ACC/AHA PRACTICE GUIDELINES
ACC/AHA guidelines for percutaneous coronary intervention (revision of the 1993 PTCA guidelines)3,3,3
A report of the American College of Cardiology/ American Heart Association Task Force on practice guidelines (Committee to revise the 1993 guidelines for percutaneous transluminal coronary angioplasty) endorsed by the Society for Cardiac Angiography and Interventions
Sidney C. Smith, Jr, MD, FACC, Chair, Committee Member,
James T. Dove, MD, FACC, Committee Member,
Alice K. Jacobs, MD, FACC, Committee Member,
J. Ward Kennedy, MD, MACC, Committee Member,
Dean Kereiakes, MD, FACC, Committee Member,
Morton J. Kern, MD, FACC, Committee Member,
Richard E. Kuntz, MD, FACC, Committee Member,
Jeffery J. Popma, MD, FACC, Committee Member,
Hartzell V. Schaff, MD, FACC, Committee Member,
David O. Williams, MD, FACC, Committee Member,
Raymond J. Gibbons, MD, FACC, Chair, Task Force Member,
Joseph P. Alpert, MD, FACC, Task Force Member,
Kim A. Eagle, MD, FACC, Task Force Member,
David P. Faxon, MD, FACC, Task Force Member,
Valentin Fuster, MD, PhD, FACC, Task Force Member,
Timothy J. Gardner, MD, FACC, Task Force Member,
Gabriel Gregoratos, MD, FACC, Task Force Member,
Richard O. Russell, MD, FACC, Task Force Member and
Sidney C. Smith, Jr, MD, FACC, Task Force Member
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Table of contents
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- I.
- II.
- III.
- Outcomes......2239iv
- Definitions of PCI Success......2239v
- Angiographic Success......2239v
- Procedural Success......2239v
- Clinical Success......2239v
- Definitions of Procedural Complications......2239v
- Acute Outcome......2239vi
- Long-Term Outcome and Restenosis......2239vii
- Predictors of Success/Complications......2239viii
- Anatomic Factors......2239viii
- Clinical Factors......2239ix
- Risk of Death......2239x
- Women......2239x
- The Elderly Patient......2239xii
- Diabetes Mellitus......2239xii
- Coronary Angioplasty After Coronary Artery Bypass Surgery......2239xiii
- Specific Technical Considerations......2239xiii
- Issues of Hemodynamic Support in High-Risk Angioplasty......2239xiii
- Comparison With Bypass Surgery......2239xiv
- Comparison With Medicine......2239xvi
- Institutional and Operator Competency......2239xvii
- Quality Assurance......2239xvii
- Operator and Institutional Volume......2239xvii
- On-Site Cardiac Surgical Backup......2239xx
- Primary PCI Without On-Site Cardiac Surgery......2239xx
- Elective PCI Without On-Site Surgery......2239xxi
- Indications......2239xxii
- Asymptomatic or Mild Angina......2239xxiii
- Angina Class II to IV or Unstable Angina......2239xxiv
- Myocardial Infarction......2239xxvii
- PCI in Thrombolytic-Ineligible Patients......2239xxvii
- Post-Thrombolysis PCI......2239xxviii
- Rescue PCI......2239xxviii
- PCI for Cardiogenic Shock......2239xxix
- PCI Hours to Days After Thrombolysis......2239xxix
- PCI After Thrombolysis in Selected Patient Subgroups......2239xxx
- Young and Elderly Post-Infarct Patients......2239xxx
- Patients With Prior MI......2239xxx
- Percutaneous Intervention in Patients With Prior Coronary Bypass Surgery......2239xxxii
- Early Ischemia After CABG......2239xxxiii
- Late Ischemia After CABG......2239xxxiii
- Early and Late Outcomes of Percutaneous Intervention......2239xxxiv
- Surgery Versus Percutaneous Reintervention......2239xxxiv
- Use of Adjunctive Technology (Intracoronary Ultrasound Imaging, Flow Velocity, and Pressure)......2239xxxv
- Intravascular Ultrasound Imaging (IVUS)......2239xxxv
- Coronary Flow Velocity and Coronary Vasodilatory Reserve......2239xxxvi
- Coronary Artery Pressure and Fractional Flow Reserve......2239xxxvii
- Management of Patients Undergoing PCI......2239xxxviii
- Experience With New Technologies......2239xxxviii
- Acute Results......2239xxxviii
- Late-Term Results......2239xxxviii
- Antiplatelet and Antithrombotic Therapies and Coronary Angioplasty (Table 31)......2239xxxviii
- Aspirin, Ticlopidine, Clopidogrel......2239xxxviii
- Glycoprotein IIb/IIIa Inhibitors......2239xxxix
- Abciximab......2239xxxix
- Eptifibatide......2239xli
- Tirofiban......2239xli
- Heparin......2239xlii
- Heparin Dosing Guidelines......2239xliii
- Post-PCI Management......2239xliii
- Post-Procedure Evaluation of Ischemia......2239xliii
- Risk-Factor Modifications......2239xliv
- Exercise Testing After PCI......2239xliv
- Special Considerations......2239xlv
- Ad-Hoc Angioplasty–PCI at the Time of Initial Cardiac Catheterization......2239xlv
- PCI in Cardiac Transplant Patients......2239xlvii
- Management of Clinical Restenosis......2239xlvii
- Background......2239xlvii
- Clinical and Angiographic Factors......2239xlvii
- Management Strategies......2239xlviii
- Restenosis After Stent Implantation (In-Stent Restenosis)......2239xlviii
- Background......2239xlviii
- Radiation for Restenosis......2239xlix
- Cost-Effectiveness Analysis for PCI......2239xlix
- Future Directions......2239l
- References......2239li
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Preamble
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It is important that the medical profession play a significant role in critically evaluating the use of diagnostic procedures and therapies in the management and prevention of disease. Rigorous and expert analysis of the available data documenting relative benefits and risks of those procedures and therapies can produce helpful guidelines that improve the effectiveness of care, optimize patient outcomes, and favorably impact the overall cost of care by focusing resources on the most effective strategies.
The American College of Cardiology (ACC) and the American Heart Association (AHA) have jointly engaged in the preparation of such guidelines in the area of cardiovascular disease since 1980. This effort is directed by the ACC/AHA Task Force on Practice Guidelines, which is charged with developing and revising practice guidelines for important cardiovascular diseases and procedures. Experts in the subject under consideration are selected from involved organizations to examine subject-specific data and write guidelines. The process includes additional representatives from other medical practitioner and specialty groups where appropriate. Writing groups are specifically charged to perform a formal literature review, weigh the strength of evidence for or against a particular treatment or procedure, and include estimates of expected-health outcomes in areas where data exist. Patient-specific modifiers, comorbidities, and issues of patient preference that might influence the choice of particular tests or therapies are considered, along with frequency of follow-up and cost-effectiveness.
The ACC/AHA Task Force on Practice Guidelines makes every effort to avoid any actual or potential conflicts of interest that might arise as a result of an outside relationship or personal interest of a member of the writing panel. Specifically, all members of the writing panel are asked to provide disclosure statements of all such relationships that might be perceived as real or potential conflicts of interest. These statements are reviewed by the parent task force, reported orally to all members of the writing panel at the first meeting, and updated as changes occur.
These practice guidelines are intended to assist physicians and other healthcare providers in clinical decision making by describing a range of generally acceptable approaches for the diagnosis, management, or prevention of specific diseases or conditions. These guidelines attempt to define practices that meet the needs of most patients in most circumstances. The ultimate judgment regarding care of a particular patient must be made by the physician and patient in light of circumstances specific to that patient.
This committee includes cardiologists with and without involvement in interventional procedures, a cardiac surgeon, and an official representative from the Society for Cardiac Angiography and Interventions (SCA&I). This document was reviewed by three official reviewers nominated by ACC, three official reviewers nominated by AHA, the AHA Committee on Diagnostic and Interventional Cardiac Catheterization, the ACC Interventional Database Committee, the ACC Cath Lab Accreditation Working Group, the ACC Cardiac Catheterization Committee, the SCA&I, and 21 outside reviewers nominated by the Writing Committee. This document was approved for publication by the governing bodies of ACC and AHA and officially endorsed by the SCA&I. These guidelines will be considered current unless the Task Force revises them or withdraws them from distribution.
Raymond J. Gibbons, MD, FACC
Chair, ACC/AHA Task Force on Practice Guidelines
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I. Introduction
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The ACC/AHA Task Force on Practice Guidelines was formed to gather information and make recommendations about appropriate use of technology for the diagnosis and treatment of patients with cardiovascular disease. Percutaneous coronary interventions (PCIs) are an important group of technologies in this regard. Although initially limited to balloon angioplasty and termed percutaneous transluminal coronary angioplasty (PTCA), PCI now includes other new techniques capable of relieving coronary narrowing. Accordingly, in this document, rotational atherectomy, directional atherectomy, extraction atherectomy, laser angioplasty, implantation of intracoronary stents and other catheter devices for treating coronary atherosclerosis are considered components of PCI. In this context PTCA will be used to refer to those studies using primarily balloon angioplasty while PCI will refer to the broader group of percutaneous techniques. These new technologies have impacted the effectiveness and safety profile initially established for balloon angioplasty. Moreover, important advances have occurred in the use of adjunctive medical therapies such as glycoprotein (GP) IIb/IIIa receptor blockers. In addition, since publication of the previous Guidelines in 1993, greater experience in the performance of PCI in patients with acute coronary syndromes and in community hospital settings has been gained. In view of these developments, further review and revision of the guidelines is warranted. This document reflects the opinion of the third ACC/AHA committee charged with revising the guidelines for PTCA to include the broader group of technologies now termed PCI.
Several issues relevant to the Committee’s process and the interpretation of the Guidelines have been noted previously and are worthy of restatement. First, PCI is a technique that has been continually refined and modified; hence continued, periodic Guideline revision is anticipated. Second, these Guidelines are to be viewed as broad recommendations to aid in the appropriate application of PCI. Under unique circumstances, exceptions may exist. These Guidelines are intended to complement, not replace, sound medical judgment and knowledge. They are intended for operators who possess the cognitive and technical skills for performing PCI and assume that facilities and resources required to properly perform PCI are available. As in the past, the indications are categorized as Class I, II, or III, based on a multifactorial assessment of risk as well as expected efficacy viewed in the context of current knowledge and the relative strength of this knowledge. Initially, this document describes the background information that forms the foundation for specific indications. Topics fundamental to coronary intervention are reviewed followed by separate discussions relating to unique technical and operational issues. Formal recommendations for the use of angioplasty are included in Section V. Indications are organized according to clinical presentation. This format is designed to enhance the usefulness of this document for the assessment and care of patients with coronary artery disease (CAD).
This document employs the ACC/AHA style classification as Class I, II, or III. These classes summarize the indications for PCI as follows: - Class I: Conditions for which there is evidence for and/or general agreement that the procedure or treatment is useful and effective.
- Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure or treatment.
- Class IIa: Weight of evidence/opinion is in favor of usefulness/efficacy.
- Class IIb: Usefulness/efficacy is less well established by evidence/opinion.
- Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful/effective, and in some cases may be harmful.
The weight of evidence in support of the recommendation for each listed indication is presented as follows: - Level of Evidence A: Data derived from multiple randomized clinical trials.
- Level of Evidence B: Data derived from a single randomized trial or nonrandomized studies.
- Level of Evidence C: Consensus opinion of experts.
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II. General considerations and background
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Coronary angioplasty was first introduced by Andreas Gruentzig in 1977 (1) as a nonsurgical method for coronary arterial revascularization. Fundamentally, the technique involved advancing a balloon tipped catheter to an area of coronary narrowing, inflating the balloon and then removing the catheter following deflation. Early reports demonstrated that balloon angioplasty could reduce the severity of coronary stenosis and diminish or eliminate objective and subjective manifestations of ischemia (2–4). Although angioplasty was clearly feasible and effective, the scope of coronary disease to be treated was quite narrow. Also, since angioplasty could result in sudden arterial occlusion and subsequent myocardial infarction (MI), immediate access to coronary bypass surgery was essential (5). With experience and time, however, the cognitive and technical aspects as much as the equipment used to perform angioplasty became more refined. Observational reports of large numbers of patients confirmed that coronary angioplasty could be applied to broad groups of coronary patients with higher rates of success and lower rates of complications when compared to initial experiences (6,7). More than 500,000 PCI procedures are performed yearly in the U.S. (8), and it has been estimated that more than 1,000,000 procedures are performed annually worldwide.
The value of coronary angioplasty was further defined by comparing its results to those of alternative methods of treatment. Randomized clinical trials have assessed the outcomes of patients treated by a strategy of initial angioplasty to one of medical therapy alone or to coronary artery bypass surgery (9–14). The results of these trials have clarified the utility of angioplasty in terms of effectiveness, complications, and patient selection. The technique of coronary angioplasty has also been expanded by the development of devices that replace or serve as adjuncts to the balloon catheter. These "new devices" have been thoroughly evaluated and have had a critical impact in enhancing the immediate- and long-term efficacy and safety of coronary angioplasty. The following section of this report expands on this background and describes the practice of PCI as it is applied today.
New coronary devices have expanded the clinical and anatomical indications for revascularization initially limited by balloon catheter angioplasty. For example, stents reduce both the acute risk of major complications and late-term restenosis. The success of new coronary devices in meeting these goals is in part represented by the less frequent use of balloon angioplasty alone (<30%) and the high (>70%) penetration of coronary stenting in the current practice of interventional cardiology (Fig. 1). Atherectomy devices and stenting, associated with improved acute angiographic and clinical outcomes compared to balloon angioplasty, in specific subsets, continue to be applied to a wider patient domain that includes multivessel disease and complex coronary anatomy. However, strong evidence (level A data from multiple randomized clinical trials) is only available for stenting in selected patients undergoing single-vessel PCI.
The range of new, non-balloon revascularization technology approved by the Food and Drug Administration (FDA) for use in native or graft coronary arteries includes balloon expandable stents, atherectomy by the Transluminal Extraction Catheter (TEC), Directional Coronary Atherectomy (DCA), rotational atherectomy, angiojet thrombolysis catheter, and Excimer Laser Coronary Atherectomy (ELCA). A variety of devices is under investigation including new designs of balloon or self-expanding stents, mechanical thrombectomy devices, and local radiation devices intended to reduce restenosis. These guidelines will focus on the FDA-approved balloon related and non-balloon coronary revascularization devices.
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III. Outcomes
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The outcomes of coronary interventional procedures are measured in terms of success and complications and are related to the mechanisms of the employed devices, as well as the clinical and anatomic patient-related factors. Complications can be divided into two categories: 1) those common to all arterial catheterization procedures and 2) those related to the specific technology used for the coronary procedure. Specific definitions of success and complications exist, and where appropriate, the definitions used herein are consistent with the ACC-National Cardiovascular Data RegistryTM Catheterization Laboratory Module Version 2.0 (15). With increased operator experience, new technology, and adjunctive pharmacotherapy, the overall success and complication rates of angioplasty have improved.
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A. Definitions of PCI success
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The success of a PCI procedure may be defined by angiographic, procedural, and clinical criteria.
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1. Angiographic success
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A successful PCI produces substantial enlargement of the lumen at the target site. The consensus definition prior to the widespread use of stents was the achievement of a minimum stenosis diameter reduction to <50% in the presence of grade 3 TIMI flow (assessed by angiography) (16). However, with the advent of advanced adjunct technology, including coronary stents, a minimum stenosis diameter reduction to <20% has been the clinical benchmark of an optimal angiographic result. Frequently, there is a disparity between the visual assessment and computer-aided quantitative stenosis measurement (17,18), and the determination of success may be problematic when success rates are self-reported.
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2. Procedural success
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A successful PCI should achieve angiographic success without in-hospital major clinical complications (e.g., death, MI, emergency coronary artery bypass surgery) during hospitalization (2,16). Although the occurrence of emergency coronary artery bypass surgery and death are easily identified end points, the definition of procedure-related MI has been debated. The development of Q-waves in addition to a threshold value of CK elevation has been commonly used. However, the significance of enzyme elevations in the absence of Q-waves remains a subject of investigation and debate. Several reports have identified non–Q-wave MIs with CK-MB elevations 3 to 5 times the upper limit of normal as having clinical significance (19,20). Thus a significant increase in CK-MB without Q-waves is considered by most to qualify as an associated complication of PCI.
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3. Clinical success
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In the short term, a clinically successful PCI includes anatomic and procedural success with relief of signs and/or symptoms of myocardial ischemia after the patient recovers from the procedure. The long-term clinical success requires that the short-term clinical success remains durable and that the patient has persistent relief of signs and symptoms of myocardial ischemia for more than 6 months after the procedure. Restenosis is the principal cause of lack of long-term clinical success when a short-term clinical success has been achieved. Restenosis is not considered a complication but rather an associated response to vascular injury. The frequency of clinically important restenosis may be judged by the frequency with which subsequent revascularization procedures are performed on target vessels after the index procedure. A very high rate of restenosis may suggest that the operator chooses an excess of lesions which are likely to restenose, such as long lesions or those involving small vessels.
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B. Definitions of procedural complications
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As outlined in the 1998 coronary interventional document (21), procedural complications are divided into six basic categories: death, MI, emergency coronary artery bypass graft (CABG) surgery, stroke, vascular access site complications, and contrast agent nephropathy. Key data elements and definitions to measure the clinical management and outcomes of patients undergoing diagnostic catheterization and/or PCI have been defined in the Clinical Data Standards document (22) and the ACC-National Cardiovascular Data RegistryTM Catheterization Laboratory Module version 2.0 (15). These rigorous definitions for key adverse events are endorsed by this Writing Committee for inclusion in the present PCI Guidelines (Table 1).
Notably, the definition of MI has evolved over the past several years. It should be emphasized that the simple categorization of MI into two classes based on the development of new Q-waves alone is no longer sufficient as a classification scheme for measuring MI following PCI. Since the measurement of CK and CK-MB are widely available, myocardial necrosis may be measured with a high level of sensitivity and specificity, regardless of the clinical presentation and associated ECG findings. The use of CK-MB for measuring myocardial necrosis is preferable to a less sensitive and less specific CK determination. The mass determination of CK-MB is now commonly used at most hospitals, and elevations of this myocardial specific enzyme are reported in nanograms per deciliter. Cardiac troponin T and I have now been introduced as measurements of myocardial necrosis and have been proven to be more sensitive and specific than CK-MB. However, prognostic criteria after PCI based on troponin T and I have not yet been developed.
Since normal values may vary among hospitals and selected patient subsets, an index of the measured value is usually reported in terms of the value of the upper limit of normal (i.e., CK-MB index of 3 corresponds to an elevation of CK-MB to 3 times its upper limit of normal value). Thus, myocardial necrosis may be determined as an abnormally elevated CK-MB index (>1), based upon 2 or 3 serial determinations during the 18 to 24 h after coronary intervention and the abnormality may range from a low index (1 to 3 times normal) with no or non-specific ECG findings, to a high index (>10 to 15 times normal) with significant ECG findings including the development of new Q-waves.
If serial determinations are performed after PCI, an abnormally high value (CK-MB >1 times normal) can be expected in 10 to 15% of balloon angioplasty procedures, 15 to 20% of stent procedures, 25 to 35% of atherectomy procedures, and >25% for any device used in saphenous vein grafts (SVGs) or long lesions with a high atherosclerotic burden, even in the absence of other signs and symptoms of MI. There is no accepted consensus on what level of CK-MB index (with or without clinical or electrocardiographic [ECG] findings) is indicative of a clinically important MI following the interventional procedure. The Writing Committee recommends that a CK-MB determination be performed on all patients who have signs or symptoms of suggestive MI following the procedure or in patients in whom there is angiographic evidence of abrupt vessel closure, important side branch occlusion, or new and persistent slow coronary flow. In patients in whom a clinically driven CK-MB determination is made, a CK-MB of >3 times the upper limit of normal would constitute a clinically significant MI. These relationships may be confounded by other factors, such as atherosclerosis.
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C. Acute outcome
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Despite the extension of coronary intervention to higher-risk patients with comorbid disease and complex coronary anatomy, angiographic and procedural success have increased since the first National Heart Lung and Blood Institute (NHLBI) registries with an associated decrease in the major complications of Q-wave MI and emergency CABG (Table 2) (2,6,23,24). Improvements in balloon technology coupled with the increased use of non-balloon devices, particularly stents (which are effective in treating abrupt vessel closure) (25) and glycoprotein IIb/IIIa platelet receptor antagonists (26–28) have favorably influenced acute procedural outcome. This combined balloon/device/ pharmacologic approach to coronary intervention in elective procedures has resulted in angiographic success rates of 96 to 99%, with Q-wave MI rates of 1 to 3%, emergency coronary artery bypass surgery rates of 0.2 to 3%, and unadjusted in-hospital mortality rates of 0.5 to 1.4% (29–34). The integrated approach utilizing adjunct pharmacologic therapies and the enormous increase in the use of stents as a primary strategy have resulted in an improved procedural outcome of balloon angioplasty (35). Improved balloon/pharmacologic techniques may achieve results comparable to those obtained with stents with the ability to perform provisional (for suboptimal result) or bail-out (for acute or threatened vessel closure) stent deployment.
It should be noted, however, that the incidence of elevated creatine kinase has increased in the new device era (36). The significance of this finding, in the absence of a clinical event, is uncertain and the subject of ongoing debate. This issue is discussed in more detail in Section VI, C.1. Post-Procedure Evaluation of Ischemia.
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D. Long-term outcome and restenosis
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Although improvements in technology, including stents and new pharmacologic therapy, have resulted in an improved acute outcome of the procedure, the impact of these changes on long-term (5 to 10 years) outcome may be less dramatic where factors such as advanced age, reduced left ventricular (LV) function, and complex multivessel disease in patients currently undergoing PCI may have a more important influence. In addition, available data on long-term outcome are mostly limited to patients undergoing PTCA. Ten-year follow-up of the initial cohort of patients treated with PTCA revealed an 89.5% survival rate (95% in patients with single-vessel disease, 81% in patients with multivessel disease) (45). In patients undergoing within the 1985–1986 NHLBI PTCA Registry (46), 5-year survival was 92.9% for patients with single-vessel disease, 88.5% for those with 2-vessel disease, and 86.5% for those with 3-vessel disease. In patients with multivessel disease undergoing PTCA in BARI (9), 5-year survival was 86.3%, and infarct-free survival was 78.7%. Specifically, 5-year survival was 84.7% in patients with 3-vessel disease and 87.6% in patients with 2-vessel disease.
In addition to the presence of multivessel disease, other clinical factors adversely impact late mortality. In randomized patients with treated diabetes in BARI, the 5-year survival was 65.5%, and the cardiac mortality was 20.6% in comparison to 5.8% cardiac mortality in patients without treated diabetes (47), although among eligible but not randomized diabetic patients, the 5-year cardiac mortality was 7.5% (48). In the 1985–1986 NHLBI PTCA Registry, 4-year survival was significantly lower in women (89.2%) in comparison to men (93.4%) (49). In addition, although LV dysfunction was not associated with an increase in in-hospital mortality or nonfatal MI in patients undergoing PTCA in the same registry, it was an independent predictor of a higher long-term mortality (50).
A major determinant of event-free survival following coronary intervention is the incidence of restenosis which had, until the development of stents, remained fairly constant, despite multiple pharmacologic and mechanical approaches to limit this process (Table 3). Depending on the definition, (i.e., whether clinical or angiographic restenosis or target lesion revascularization is measured), the incidence of restenosis following coronary intervention had been 30 to 40%, and higher in certain clinical and angiographic subsets (51).
The pathogenesis of the response to mechanical coronary injury is thought to relate to a combination of growth factor stimulation, smooth muscle cell migration and proliferation, organization of thrombus, platelet deposition, and elastic recoil (69,70). In addition, dynamic change in vessel size (or lack of compensatory enlargement) has been implicated (71). It has been suggested that attempts to reduce restenosis have failed, in part due to lack of recognition of the importance of this factor (72). Although numerous definitions of restenosis have been proposed, >50% diameter stenosis at follow-up angiography has been most frequently used. However, it is now recognized that the response to arterial injury is a continuous rather than a dichotomous process, occurring to some degree in all patients (73). Therefore, cumulative frequency distributions of the continuous variables of minimal lumen diameter or percent diameter stenosis are now used to evaluate restenosis in large patient populations (74) (Fig. 2).
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Figure 2 Balloon stent versus balloon angioplasty in coronary artery disease. Cumulative frequency distribution curves for the two study groups, showing minimum lumen diameters measured before and after intervention and follow-up (B), the percentage of stenosis at follow-up, and the percentage of patients with clinical end points. Significant differences were apparent that consistently favored the stent group over the angioplasty group with respect to the increased minimal lumen diameter at intervention (A) and follow-up (B), the percentage of stenosis at follow-up (C), and the incidence of major clinical events (D). The vertical dashed line in D indicated the end of the study. Reproduced with permission from Serruys PW, et al. N Engl J Med 1994;331:489–95 (32).
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Although multiple clinical factors (diabetes, unstable angina, acute MI, prior restenosis) (75,76), angiographic factors (proximal left anterior descending artery, small vessel diameters, total occlusion, long lesion length, SVG) (77), and procedural factors (higher post-procedure percent diameter stenosis, smaller minimal lumen diameter, and smaller acute gain) (74) have been associated with an increased incidence of restenosis, the ability to integrate these factors and predict the risk of restenosis in individual patients following the procedure remains difficult. The most promising potential approaches to favorably impact the restenosis process relate to: 1) the ability to decrease elastic recoil and remodeling using intracoronary stents, and 2) to the ability to reduce intimal hyperplasia using catheter-based ionizing radiation. More than 6,300 patients have been studied in 12 randomized clinical trials to assess the efficacy of PTCA versus stents to reduce restenosis (Table 4).
The pivotal BENESTENT (32) and STRESS Trials (31) documented that stents significantly reduce angiographic restenosis in comparison to balloon angioplasty (BENESTENT: 22% vs. 32%; STRESS: 32% vs. 42%, respectively). These results have been corroborated in the BENESTENT II trial in which the angiographic restenosis rate was reduced by 45% (from 31 to 16% in patients treated with balloon angioplasty versus heparin-coated stents, respectively) (66).
In addition, randomized studies in patients with in-stent restenosis have shown that both intracoronary gamma and beta radiation significantly reduced the rate of subsequent angiographic and clinical restenosis by 30 to 50% (78–81). Late subacute thrombosis was observed in some of these series (82), but this syndrome has resolved with judicious use of stents and extended adjunct antiplatelet therapy with ticlopidine or clopidogrel. Also, in a preliminary study of patients undergoing successful balloon angioplasty, delivery of intracoronary beta radiation resulted in a restenosis rate of 15% (83).
When technically feasible, in patients who experience restenosis, it is standard practice to perform repeat PCI. In this setting, stents are being used with the hope of decreasing the rate of subsequent restenosis. However, in-stent restenosis, particularly when diffuse, represents a challenging problem. The efficacy of various treatment modalities for in-stent restenosis is under active investigation.
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E. Predictors of success/complications
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1. Anatomic factors.
Target lesion anatomic factors related to adverse outcomes have been widely examined. Lesion morphology and absolute stenosis severity were identified as the prominent predictors of immediate outcome during PTCA in the pre-stent era (93,94). Abrupt vessel closure, due primarily to thrombus or dissection, was reported in 3 to 8% of patients and was associated with certain lesion characteristics (95–97). The risk of PTCA in the pre-stent era relative to anatomic subsets has been identified in previous NHLBI PTCA Registry data (6) and by the ACC/AHA Task Force (16,98). The lesion classification based on severity of characteristics proposed in the past (98–100) has been principally altered using the present PCI techniques which capitalize on the ability of stents to manage initial and subsequent complications of coronary interventions (101). As a result the Committee has revised the previous ACC/AHA lesion classification system to reflect low, moderate, and high risk (Table 5) in accordance with the PCI Clinical Data Standards from the ACC-National Cardiovascular Data RegistryTM (15).
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2. Clinical factors
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Coexistent clinical conditions can increase the complication rates for any given anatomic risk factor. For example, complications occurred in 15.4% of diabetic patients versus 5.8% of nondiabetic patients undergoing balloon angioplasty in a multicenter experience (94,97). Several studies have reported specific factors associated with increased risk of adverse outcome following balloon angioplasty. These factors include advanced age, female gender, unstable angina, congestive heart failure (CHF), diabetes, and multivessel CAD (9,93,94,102,103) (Table 6). The BARI trial found that patients with diabetes and multivessel CAD had an increased periprocedural risk of ischemic complications and increased 5-year mortality in comparison to patients without diabetes or in comparison to patients with diabetes undergoing bypass surgery using internal thoracic arterial grafts (9,38). Patients with impaired renal function, especially diabetics, are at increased risk for contrast nephropathy (104) and increased 30-day and 1-year mortality.
Increased risk for severe compromise in LV function or fatal outcome may occur with a complication of a vessel that also supplies collateral flow to viable myocardium. Certain variables were used to prospectively identify patients at risk for significant cardiovascular compromise during PTCA (105,106). These resulted in a composite 4-variable scoring system, prospectively validated to be both sensitive and specific in predicting cardiovascular collapse for failed PTCA and includes: 1) percentage of myocardium at risk (e.g., >50% viable myocardium at risk and LV ejection fraction of <25%), 2) pre-angioplasty percent diameter stenosis, 3) multivessel CAD, and 4) diffuse disease in the dilated segment (107) or a high myocardial jeopardy score (108). Patients with higher pre-procedural jeopardy scores were shown to have a greater likelihood of cardiovascular collapse when abrupt vessel closure occurred during PTCA (105). The clinical risk factors associated with in-hospital adverse events have been further evaluated with additional experience during the PCI era and summarized based on odds ratio >2.0 or results of multivariate analysis (Table 6).
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3. Risk of death
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In the majority of patients undergoing elective PCI, death as a result of PCI is directly related to the occurrence of coronary artery occlusion and is most frequently associated with pronounced LV failure (105,106) (Table 6). The clinical and angiographic variables associated with increased mortality include advanced age, female gender, diabetes, prior MI, multivessel disease, left main or equivalent coronary disease, a large area of myocardium at risk, pre-existing impairment of LV or renal function, and collateral vessels supplying significant areas of myocardium that originate distal to the segment to be dilated (Table 6) (9,93,95,97,102–105,107–110).
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4. Women
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In comparison to men, women undergoing PCI are older and have a higher incidence of hypertension, diabetes mellitus, hypercholesterolemia, and comorbid disease (49,111–114). Women also have more unstable angina and a higher functional class of stable angina (Canadian Cardiovascular Society Class III and IV) for a given extent of disease (115). Yet, despite the higher-risk profile in women, the extent of epicardial coronary disease is similar (or less) in comparison to men. In addition, although women presenting for revascularization have less multivessel disease and better LV systolic function, the incidence of CHF is higher in women than in men. The reason for this gender paradox is unclear, but it has been postulated that women have more diastolic dysfunction, perhaps based on older age and hypertension, in comparison to men (116).
Early reports of patients undergoing PTCA revealed a lower procedural success rate in women (112); however, more recent studies have noted similar angiographic outcome and incidence of MI and emergency coronary artery bypass surgery in women and men (49). Although reports have been inconsistent, in several large-scale registries, in-hospital mortality is significantly higher in women, and an independent effect of gender on acute mortality following PTCA persists after adjustments for the baseline higher-risk profile in women (49,117). The reason for the increase in mortality is unknown, but small vessel size and hypertensive heart disease in women have been thought to play a role. Although a few studies have noted that gender is not an independent predictor of mortality when body surface area (a surrogate for vessel size) is accounted for (111), the impact of body size on outcome has not been thoroughly evaluated. The higher incidence of vascular complications, coronary dissection, and perforation in women undergoing coronary intervention has been attributed to the smaller vasculature in women in comparison to men. In addition, diagnostic intravascular ultrasound (IVUS) studies have not detected any gender-specific differences in plaque morphology or luminal dimensions once differences in body surface area were corrected, suggesting that differences in vessel size account for some of the apparent early and late outcome differences previously noted in women (118). It has also been postulated that the volume shifts and periods of transient ischemia during coronary angioplasty are less well tolerated by the hypertrophied ventricle in women, and CHF has shown to be an independent predictor of mortality in both women and men undergoing coronary angioplasty (119).
An improved outcome has been reported in women undergoing both coronary balloon and new device angioplasty, despite the fact that the women (similar to men) are older and with more complex disease than women treated previously. In fact, in the 1993–1994 NHLBI PTCA Registry (open to women only), procedural success was higher and major complications lower in comparison to women treated in the 1985–1986 registry (24). Additionally, patients undergoing balloon angioplasty in BARI, in-hospital mortality, MI, emergency coronary artery bypass surgery rates, and 5-year mortality were similar in women and men, although women had a higher incidence of periprocedural CHF and pulmonary edema (120).
In a registry of 373 consecutive patients undergoing directional coronary atherectomy (DCA), although early and late outcomes were similar, the lower procedural success observed in women (73% vs. 83%, p = 0.011) was again attributed to their smaller vessel caliber (121). Therefore, although women presenting for coronary revascularization have a higher-risk profile, currently the acute and long-term outcomes are similar to those in men. Much of the increase in adverse outcome seen in women can be accounted for by comorbidities, although gender imparts a small independent effect. Finally, it is important to note that in women undergoing coronary intervention, the acute outcome has improved and the long-term outcome remains excellent. Therefore, coronary intervention should be considered for women in need of revascularization with the anticipation of a favorable outcome (Table 7).
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5. The elderly patient
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Age >75 years is one of the major clinical variables associated with increased risk of complications (125). In the elderly population, the morphologic and clinical variables are compounded by advanced years with the very elderly having the highest risk of adverse outcomes (126). In octogenarians, although feasibility has been established for most interventional procedures, the risk of both percutaneous and nonpercutaneous revascularization is increased (127,128). Octogenarians undergoing percutaneous intervention have a higher incidence of prior MI, lower LV ejection fraction, and more frequent CHF (129). In the stent era, procedural success rates and short-term outcomes are comparable to those for nonoctogenarians (130). Thus, with rare exception (primary PCI for cardiogenic shock for patients >75 years), a separate category has not been created in these Guidelines for the elderly. However, their higher incidence of comorbidities should be taken into account when considering the need for PCI.
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6. Diabetes mellitus
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In the TIMI-IIB study of MI, patients with diabetes mellitus had significantly higher 6-week (11.6% vs. 4.7%), 1-year (18.0% vs. 6.7%), and 3-year (21.6% vs. 9.6%) mortality rates compared to nondiabetic patients (131). Patients with diabetes with a first MI who were randomly assigned to the early invasive strategy faired worse than those managed conservatively (42-day mortality: death or MI, or death alone 14.8% vs. 4.2%; p < 0.001) (132). Early catheterization and intervention strategy after thrombolysis was of little benefit in these patients with diabetes. Routine catheterization and angioplasty in this patient subgroup should be based on clinical need and ischemic risk stratification.
Stenting decreases the need for target revascularization procedures in diabetic patients compared with balloon angioplasty. The efficacy of stenting with glycoprotein IIb/IIIa inhibitors was assessed in the diabetic population compared to those without diabetes in a substudy of the EPISTENT trial (133). One hundred seventy-three diabetic patients were randomized to stent/placebo combination, 162 patients to stent/abciximab combination, and 156 patients to balloon angioplasty/abciximab combination. For the composite end point of death, MI, or target-vessel revascularization, the rates were as follows: 25%, 23%, and 13% for the stent/placebo, balloon/abciximab, and stent/abciximab groups (p = 0.005). Irrespective of revascularization strategy abciximab significantly reduced 6-month death and MI rate in patients with diabetes for all strategies. Likewise, 6-month target-vessel revascularization was reduced in the stent/abciximab group approach. One-year mortality for diabetics was 4.1% for the stent/placebo group and 1.2% for the stent/abciximab group. Although this difference was not significant, the combination of stenting and abciximab among diabetics resulted in a significant reduction in 6-month rates of death and target-vessel revascularization compared to stent/placebo or balloon angioplasty/abciximab therapy (133). The BARI trial, in which stents and abciximab were not used, showed that survival was better for patients with treated diabetes undergoing CABG surgery with an arterial conduit than for those undergoing angioplasty. A discussion about the selection of diabetic patients for surgical revascularization or PCI may be found in Section III. Outcomes, F. Comparison With Bypass Surgery.
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7. Coronary angioplasty after CABG surgery
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Although speculated to be at higher risk, patients having PCI of native vessels after prior coronary bypass surgery have, in recent years, nearly equivalent interventional outcomes and complication rates compared to patients having similar interventions without prior surgery. For PCI of SVG, studies indicate that the rate of successful angioplasty exceeds 90%, death <1.2%, and Q-wave MI <2.5% (Table 8). The incidence of non–Q-wave MI may be higher than that associated with native coronary arteries (134–136).
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Table 8 Probability of Success, Complications, and Restenosis After Balloon Angioplasty or Stenting in Patients Following Coronary Bypass Surgery
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In consideration of PCI for SVG, the age of the SVG and duration and severity of myocardial ischemia should be taken into consideration. Use of GP IIb/IIIa blockers has not been shown to improve results of angioplasty in vein grafts. The native vessels should be treated with PCI if feasible. Patients with older and/or severely diseased SVGs may benefit from elective repeat CABG surgery rather than PCI (137,138).
In some circumstances, PCI of a protected left main coronary artery stenosis with a patent and functional left anterior descending or left circumflex coronary conduit can be considered. Percutaneous coronary interventions should be recognized as a palliative procedure with the potential to delay the ultimate application of repeat CABG surgery.
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8. Specific technical considerations
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Certain outcomes of PCI may be specifically related to the technology utilized for coronary recanalization. The occurrence of periprocedural CPK-MB elevation 3 times the upper limit of normal appears to occur more frequently following use of ablative technology such as rotational or directional atherectomy (20,34,58,140,146). Antecedent unstable angina appears to be a clinical predictor of slow flow and periprocedural infarction following ablative technologies (147), and direct platelet activation has been demonstrated to occur with both directional and rotational atherectomy (148). In support of the premise that platelets play a pathophysiologic role in periprocedural MI are observations that the presence and magnitude of CK-MB elevation following ablative technologies can be reduced to levels observed following balloon angioplasty by the administration of prophylactic platelet GP IIb/IIIa receptor blockade (149,150).
Coronary perforation may occur more commonly following the use of ablative technologies, including rotational, directional or extraction atherectomy, and excimer laser coronary angioplasty. However, the incidence of perforation has been reported variably to be 0.10 to 1.14% with balloon angioplasty; 0.25 to 0.70% with directional coronary atherectomy; 0.0 to 1.3% with rotational atherectomy; 1.3 to 2.1% with extraction atherectomy; and, 1.9 to 2.0% following excimer laser coronary angioplasty (151,152). Coronary perforation complicates PCI more frequently in the elderly and in women. While 20% of perforations may be secondary to the coronary guidewire, most are related to the specific technology used. Perforation is usually (80 to 90%) evident at the time of the interventional procedure and should be a primary consideration in the differential diagnosis for cardiac tamponade manifest within 24 h of the procedure. Perforations may be classified based on angiographic appearance as Type I—extraluminal crater without extravasation; Type II—pericardial and myocardial blush without contrast jet extravasation; and Type III—extravasation through a frank ( 1 mm) perforation (151). In the absence of extravasation (Type III), the majority of perforations may be effectively managed without urgent surgical intervention. Type III perforations have been successfully managed nonoperatively with pericardiocentesis, reversal of anticoagulation, and either prolonged perfusion balloon inflation at the site of perforation or deployment of a covered stent. If these approaches are not successful, perforations caused by directional atherectomy catheters usually require surgical repair (Table 9).
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9. Issues of hemodynamic support in high-risk angioplasty
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Controversy exists about the ability to predict hemodynamic compromise during coronary angioplasty. Hemodynamic compromise, defined as a decrease in systolic blood pressure to an absolute level <90 mm Hg during balloon inflation, was often associated with LV ejection fraction <35%, >50% of myocardium at risk, and PTCA performed on the last remaining vessel (95,107).
Early feasibility studies of high-risk PTCA using percutaneous cardiopulmonary support (CPS) indicated that although initial likelihood of success was high, vascular morbidity was also high with an incidence of 43% (153,154). However, no study has published data to validate commonly employed high-risk categorization.
Elective high-risk PCI can be performed safely without intra-aortic balloon pump (IABP) or CPS in most circumstances. Emergency high-risk PCI such as direct PCI for acute MI can usually be performed without IABP or CPS. CPS for high-risk PCI should be reserved only for patients at the extreme end of the spectrum of hemodynamic compromise, such as those patients with extremely depressed LV function and patients in cardiogenic shock. However, it should be noted that in patients with borderline hemodynamics, ongoing ischemia, or cardiogenic shock, insertion of an intra-aortic balloon just prior to coronary instrumentation has been associated with improved outcomes (155,156). Furthermore, it is reasonable to obtain vascular access in the contralateral femoral artery prior to the procedure in patients in whom the risk of hemodynamic compromise is high, thereby facilitating intra-aortic balloon insertion, if necessary.
For high-risk patients, clinical and anatomic variables influencing complications and outcome should be assessed before the performance of PCI to determine procedural risk, the risk of abrupt vessel closure, and potential for cardiovascular collapse. In patients having a higher-risk profile, consideration of alternative therapies, particularly coronary bypass surgery, formalized surgical standby, or periprocedural hemodynamic support should be addressed before proceeding with PCI.
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F. Comparison with bypass surgery
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The major advantage of PCI is its relative ease of use, avoiding general anesthesia, thoracotomy, extracorporeal circulation, CNS complications, and prolonged convalescence. Repeat PCI can be performed more easily than repeat bypass surgery, and revascularization can be achieved more quickly in emergency situations. The disadvantages of PCI are early restenosis and the inability to relieve many totally occluded arteries and/or those vessels with extensive atherosclerotic disease.
Coronary artery bypass surgery has the advantages of greater durability (graft patency rates exceeding 90% at 10 years with arterial conduits) (157) and more complete revascularization irrespective of the morphology of the obstructing atherosclerotic lesion. Generally speaking, the greater the extent of coronary atherosclerosis and its diffuseness, the more compelling the choice of coronary artery bypass surgery, particularly if LV function is depressed. Patients with lesser extent of disease and localized lesions are good candidates for endovascular approaches.
PTCA and coronary artery bypass surgery have been compared in many nonrandomized and randomized studies. The most accurate comparisons of outcomes are best made from prospective randomized trials of patients suitable for either treatment. Although results of these trials provide useful information for selection of therapy in several patient subgroups, prior studies of PTCA may not reflect outcome of current PCI practice, which includes frequent use of stents and antiplatelet drugs. Similarly, many previous studies of CABG may not reflect outcome of current surgical practice in which arterial conduits are used whenever practicable. Beating heart bypass operations are also employed for selected patients with single-vessel disease with reduced morbidity (158). In addition, patients are selected for PCI (with or without stenting) because of certain lesion characteristics, and these anatomical criteria are not required for CABG.
Randomized trials also must be interpreted carefully. It is unethical to withhold subsequent PCI or CABG from patients solely because they fail an earlier treatment; thus, comparative prospective studies can only compare initial strategies of revascularization. This critically important point is frequently overlooked by those who claim that a randomized study proves equally good outcome of one method of revascularization over the other. Indeed, it would seem highly unlikely that any randomized trial of PCI and CABG could demonstrate a survival advantage of an initial revascularization method as long as frequent crossover to alternate and/or new therapies is allowed.
Despite these limitations, some generalizations can be made from comparative trials of PTCA and CABG. First, for most patients with single-vessel disease, late survival is similar with either revascularization strategy, and this might be expected given the generally good prognosis of most patients with single-vessel disease managed medically (159–161).
Two prospective clinical trials have evaluated PTCA and CABG for revascularization of isolated disease of the left anterior descending coronary artery. Investigators in the Medicine, Angioplasty or Surgery Study (MASS) used a combined end point of cardiac death, MI, or refractory angina requiring repeat revascularization by surgery; at 3 years of follow-up, this combined end point occurred in 24% of PTCA patients, in 17% of medical patients, and in 3% of surgical patients (162). Importantly, there was no difference in overall survival in the three groups. In the Lausanne trial of 134 patients with isolated left anterior descending artery disease treated by either PTCA (68 patients) or bypass with an internal mammary artery, survival was similar in the two groups, and 94% of PTCA patients and 95% of CABG patients were free of limiting symptoms (163). However, patients in the PTCA group took more antianginal drugs than surgical patients, and at median follow-up of 2.5 years, 86% of CABG-treated versus 43% of PTCA-treated patients were free from late events (p < 0.01); this difference was primarily due to restenosis (32%) requiring subsequent CABG (16%) or PTCA (15%). It should be emphasized that neither of the two aforementioned trials included stenting, a technique which would be expected to reduce rates of early restenosis by as much as 50% in appropriately selected lesions (86,164,165).
In a similar manner, the 3-year follow-up of the Argentine randomized trial of PTCA versus CABG multivessel disease (ERACI study) (164) demonstrated that in patients randomized to angioplasty or bypass surgery, the 1-, 3-, and 5-year follow-up results indicated that freedom from combined cardiac events was significantly greater for bypass surgery than for angioplasty group (77% vs. 47%; p < 0.001). However, there were no differences in overall and cardiac mortality or in the frequency of MI between the two groups. Patients who had bypass surgery were more frequently free of angina (79% vs. 57%) and had fewer additional reinterventions (6.3% vs. 37%) than in patients who had angioplasty. This study indicated that freedom from combined cardiac events at 3-year follow-up was greater in bypass patients than those who had angioplasty and that the angioplasty group had a higher incidence of recurrence of angina and need for repeat procedures. Cumulative cost at 3 years was greater for surgery than for the angioplasty group.
In the ARTS trial, the first trial to compare stenting with surgery, there was no significant difference in mortality between PCI and surgical groups at one year. The main difference compared to previous PTCA and CABG trials was an approximate 50% reduction in the need for repeat revascularization in a group randomized to PCI with stent placement (166).
Direct comparison of initial strategies of PCI or CABG in patients with multivessel coronary disease is possible only by randomized trials because of selection criteria of patients for PCI. There have been 5 large (>300 patients) randomized trials of PTCA versus CABG and 2 smaller studies; characteristics of the studies are summarized in Table 10 (9–12,164,167,168). These trials demonstrate that in appropriately selected patients with multivessel coronary disease, an initial strategy of standard PTCA yields similar overall outcomes (e.g., death, MI) compared to initial revascularization with coronary artery bypass. In BARI, the only trial with the largest patient enrollment to look at survival alone, 5-year survival was 86.3% for those assigned to PTCA versus 89.3% for those assigned to CABG (p = 0.19), and 5-year survivals free from Q-wave MI were 78.7% and 80.4%, respectively. However, after 5 years of follow-up, 54% of those assigned to PTCA had undergone additional revascularization procedures compared to 8% of the patients assigned to CABG (9). Indications for PCI for various patient subsets are presented in Section V. Indications.
An important exception to the conclusion of the relative safety of PCI in multivessel disease is the subgroup of patients with treated diabetes mellitus. Among treated diabetic patients in BARI assigned to PTCA, 5-year survival was 65.5% compared to 80.6% for patients having CABG (p = 0.003); the improved outcome with CABG was due to reduced cardiac mortality (5.8% vs. 20.6%, p = 0.0003), which was confined to those receiving at least 1 internal mammary artery graft (9). Better survival of diabetic patients with multivessel disease treated initially with CABG has been observed in a large retrospective study from Emory (169) and may be due to the apparent additive effects of diabetes mellitus and instrumentation of an artery on development of new stenotic lesions (170). As compelling as these reports may be, it is of interest that treated diabetic patients enrolled in the BARI Registry did not show a similar advantage for CABG over PCI, suggesting that physician judgment in the selection of diabetic patients for PCI may be an important factor (38,48).
Moreover, direct comparison between outcomes of PCI and CABG among the diabetic population has not been made using platelet receptor antagonists with PCI. In this setting, PCI may be more competitive with CABG. The EPISTENT trial demonstrated significant reductions of major cardiac events at 30 days and at 6 months in the abciximab groups undergoing stenting compared to those with stenting and placebo (133).
Randomized trials of PTCA and CABG provide additional information on symptom relief, quality of life, and costs of the two revascularization methods. Both revascularization techniques relieve angina. However, to achieve similar clinical outcomes, patients treated with PTCA are more likely to require further interventions than patients having surgery. Analysis of quality-of-life data from BARI suggests that functional status including activities of daily living improved less in patients assigned to PTCA than in those assigned to CABG (p < 0.05), although patients with initial PTCA returned to work five weeks sooner than did patients undergoing operation (p < 0.001) (171).
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G. Comparison with medicine
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There has been a considerable effort made to evaluate the relative effectiveness of bypass surgery as compared to PCI for coronary artery revascularization. In contrast to this, very little effort has been directed toward comparing medical therapy with PCI for the management of stable and unstable angina. 3 Randomized trials are currently available comparing PCI with the medical management of angina (172–174). The ACME investigators randomized 212 patients with single-vessel disease, stable angina pectoris, and ischemia on treadmill testing to PTCA or medical therapy. This trial demonstrated superior control of symptoms and better exercise capacity in patients managed with PTCA as compared to medical therapy. Death and MI were infrequent and similar in both groups. The Veterans Administration ACME trial investigators long-term results in an additional 101 randomized patients with double-vessel disease not previously reported (175) indicated that patients randomized to medical therapy or PTCA had similar improvement in exercise duration, freedom from angina, and improvement in quality of life at the time of 6-month follow-up. Thus, these patients with double-vessel angioplasty did not demonstrate superior control of their symptoms as compared to medical therapy as was experienced by the ACME patients with single-vessel disease. This small study suggests that PTCA is less effective in controlling symptoms in patients with double-vessel and stable angina as compared to single-vessel disease.
The RITA-2 investigators randomized 1,018 stable patients with stable angina to PTCA or conservative (medical) therapy (173). Patients who had inadequate control of their symptoms with optimal medical therapy were allowed to cross-over to myocardial revascularization. The combined end point of the trial was all cause mortality and nonfatal MI. The 504 PTCA and 514 medical patients were followed for a mean of 2.7 years. Death and definite MI occurred in 32 of the PTCA patients (6.3%) and in 17 of the medical patients (3.3%), p = 0.02. Of the 18 deaths (11 PTCA and 7 medical) only 8 were due to heart disease. Twenty-three percent of the medical patients required a revascularization procedure during follow-up. Angina improved in both groups, but there was a 16.5% absolute excess of grade 2 or worse angina in the medical group at 3 months following randomization (p < 0.001). The PTCA patients also had greater improvement in their exercise duration as compared to the medical patients (p < 0.001). During follow-up 40 patients randomized to PTCA required CABG surgery (7.9%) as compared to 30 of the medical patients (5.8%). Thus, RITA-2 demonstrated that PTCA results in better control of symptoms of ischemia and improves exercise capacity as compared to medical therapy, but is associated with a higher combined end point of death and periprocedural MI. It is important to remember that although the patients in this trial were asymptomatic or had only mild angina, 62% of them had multivessel CAD and 34% had significant disease in the proximal segment of the left anterior descending coronary artery (176). Thus, most of these patients had severe anatomic CAD.
The Asymptomatic Cardiac Ischemia Pilot (ACIP) study provides additional information comparing medical therapy with PTCA or CABG revascularization in patients with documented CAD and asymptomatic ischemia by both stress testing and ambulatory ECG monitoring (176). This trial randomized 558 patients suitable for revascularization by PTCA or CABG to 3 treatment strategies: angina-guided drug therapy (n = 183), angina plus ischemia-guided drug therapy (n = 183), and revascularization by PTCA or CABG surgery (n = 192). Of the 192 patients that were randomized to revascularization, 102 were selected for PTCA and 90 for CABG. At 2 years of follow-up, death or MI had occurred in 4.7% of the revascularization patients as compared to 8.8% of the ischemia-guided group and 12.1% of the angina-guided group (p < 0.01). Because a large portion of the patients underwent CABG surgery instead of PTCA in order to achieve complete revascularization, it is not appropriate to directly compare these results with RITA-2. Nonetheless, the ACIP study suggests that outcomes of revascularization with CABG surgery and PTCA are very favorable compared to medical therapy in patients with asymptomatic ischemia with or without mild angina. It should be emphasized that aggressive lipid-lowering therapy was not widely employed in the medical treatment arm of ACIP.
AVERT (174) randomly assigned 341 patients with stable CAD, normal LV function, and Class I and/or II angina to PTCA or medical therapy with 80 mg daily atorvastatin (mean LDL = 77 mg/dl). At 18 months follow-up, 13% of the medically treated group had ischemic events as compared to 21% of the PTCA group (p = 0.048). Angina relief was greater in those treated with PTCA. Although not statistically different when adjusted for interim analysis, these data suggest that in low-risk patients with stable CAD, aggressive lipid-lowering therapy can be as effective as PTCA in reducing ischemic events.
Based on the limited data available from randomized trials comparing medical therapy with PTCA, it seems prudent to consider medical therapy for the initial management of most patients with Canadian Cardiovascular Society Classification Class I and II and reserve PTCA and CABG for those patients with more severe symptoms and ischemia. The symptomatic individual patient who wishes to remain physically active, regardless of age, will more often require PCI although one trial (RITA-2) (94,173) suggests that this option may be associated with an increased initial risk. The results of the ACIP trial indicate that higher-risk patients with asymptomatic ischemia and significant CAD who undergo complete revascularization with CABG or PTCA may have a better outcome as compared to those with medical management. This finding had not been previously demonstrated by trials comparing medical management with surgical revascularization (16,98) (Table 11). In contrast, the results of AVERT indicate revascularization provides no benefit when compared to aggressive lipid-lowering therapy in low-risk patients. Clinical Outcomes Utilization Revascularization and Aggressive Drug Evaluation (COURAGE) trial, a 3,250 patient-based trial, will compare intensive medical therapy with revascularization over 5 to 7 years. It is anticipated that this trial will answer many questions, in addition to quality-of-life assessment and economic cost analysis (177–179) Patients with unstable angina and non–ST-segment elevation MI have been randomized to medical therapy or PCI in the FRISC II and TACTICS TIMI 18 trials. These trials utilizing stenting as the primary therapy have favored the invasive approach. They are discussed under Section V. B.
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IV. Institutional and operator competency
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A. Quality assurance.
A mechanism for valid peer review must be established and ongoing at each institution performing PCI. Interventional cardiology procedures are associated with complications that in general are inversely related to operator and institutional volume (43,180–183). The mechanism for institutional review should provide an opportunity for interventionalists as well as physicians who do not perform angioplasty, but are knowledgeable about it, to review overall results of the program on a regular basis. The responsible supervising authority should monitor the following issues as outlined in Table 12.
The institutional credentialing committee should document that an interventionalist wishing to start practice meets the established training criteria, including those of the ACC Task Force on Training in Cardiac Catheterization and Interventional Cardiology (21,185,186). The ACC Training Statement (186) for coronary invasive training requires a 3-year comprehensive cardiac program with 12 months of training in diagnostic catheterization during which the trainee performs 300 diagnostic catheterizations with 200 of those being the primary operator. The interventional training requires a fourth year of fellowship during which the trainee should perform more than 250 interventional procedures, but not more than 600/year (186). To be eligible for the American Board of Internal Medicine (ABIM) certifying examination in interventional cardiology, a trainee must be actively involved in at least 250 interventional procedures during a 4th year of interventional cardiology fellowship. Only one trainee may receive credit for the intervention on a given patient. Until 2003, the practicing interventionalist can qualify for the examination by active involvement in interventional cardiology, including the performance of at least 150 interventions over the prior 2 year period (187). Credentials committees should evaluate the physicians’ outcomes to be certain that volume and results meet the current standards or benchmarks for successful management (21). These benchmarks refer to procedural rates of unadjusted mortality (0.9%) and emergency coronary artery bypass surgery ( 3.0%). It should be noted that these benchmarks are derived from PTCA performed in New York State on all procedures including those for complicated acute MI and that they were gathered before the use of stents and platelet GP IIb/IIIa inhibitors. Thus, the standard for benchmark complication rates will be subject to future revision as newer data emerge. It is important that institutions assist with these efforts by participating in active database efforts to track clinical and procedural information for individual operators and their institutions. In the future, certification by the ABIM in Interventional Cardiology should be required.
This Writing Committee agrees with the ACC Task Force recommendations for the Assessment and Maintenance of Proficiency in Coronary Interventional Procedures (21). Institutions performing PCI should meet the following standards as outlined in Tables 13 and 14 (21,184,186).
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B. Operator and institutional volume
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The proliferation of small angioplasty or small surgical programs to support such angioplasty programs is strongly discouraged. Several studies have identified procedural volume as a determining factor for frequency of complications with PCI (43,182,183,188–191). Kimmel, using data from the Society of Cardiac Angiography and Interventions (SCA&I), found that an inverse relationship existed between the number of angioplasty procedures performed at a hospital and the rate of major complications (181). These results were risk-stratified and independent of the patient-risk profile. Significantly fewer complications occurred in laboratories performing 400 angioplasty procedures per year. Conversely, low-volume hospitals were associated with higher rates of emergency coronary artery bypass surgery and death (182). Improved outcomes were identified with a threshold volume of 75 Medicare angioplasties per physician and 200 Medicare angioplasty procedures per hospital. Using a 35 to 50% ratio of Medicare patients, the threshold value was 150 to 200 angioplasty procedures/cardiologist and 400 to 600 angioplasty procedures/institution (40). Other studies have also supported the relationship of complications to procedural volume (43,180,183). Although some investigators have suggested that low procedure volume does not contribute to poor outcomes (188,192), these studies are small in number and underpowered for analysis (189). Development of small cardiovascular surgical programs to support angioplasty is a poor use of resources that will likely lead to suboptimal results (190).
Given the concerns regarding operator volume and surgical standby, it is recommended that PCI be performed by higher volume operators (75 cases/year) with advanced technical skills (e.g., subspecialty certification) at institutions with fully equipped interventional laboratories and experienced support staff. This setting will most often be in a high-volume center (>400 cases/year) associated with an on-site cardiovascular surgical program (193). Similar concerns have been identified and supported by the Task Force for Practice Guidelines for Coronary Angiography (194).
Intuitively, it is clear that it would be best for the rare patient requiring surgery after elective PCI to remain in the same hospital rather than have the patient and family undergo the confusion, stress, and anxiety of emergency transfer. Given the widespread availability of sophisticated interventional/surgical programs in the U.S., it is difficult to demonstrate a need for additional low-volume programs to do elective angioplasty except in underserved areas that are geographically far removed from major centers. This Committee acknowledges that not every cardiologist desiring to do PCI should perform these procedures and not every hospital anxious to have an interventional program should start one (191). This caveat is particularly true where there are high-volume programs and operators nearby. In these situations, operators should be subspecialty board certified.
The Committee, therefore, recommends that angioplasty is best done by high-volume operators in high-volume institutions. Any change in this recommendation awaits further data confirming the comparable safety and outcomes for patients treated in an alternative manner. The Committee cannot recommend angioplasty by low-volume operators (<75 cases/year) working in low-volume institutions (<200 cases/year) with or without on-site surgical coverage. As noted earlier, ongoing investigational experience and clinical data are mandatory if these recommendations are to be modified.
Recommendations for PCI Institutional and Operator Volumes at Centers With Onsite Cardiac Surgery (21,186) (Table 14)
Class I - PCI done by operators with acceptable volume (75) at high-volume centers (>400). (Level of Evidence: B)
Class IIa - PCI done by operators with acceptable volume (75) at low-volume centers (200 to 400). (Level of Evidence: C)
- PCI done by low-volume operators (<75) at high-volume centers (>400). Note: Ideally operators with an annual procedure volume <75 should only work at institutions with an activity level of >600 procedures/year.* (Level of Evidence: C)
Class III - PCI done by low-volume operators (<75) at low-volume centers (200 to 400). Note: An institution with a volume <200 procedures/year, unless in a region that is underserved because of geography, should carefully consider whether it should continue to offer service.* (Level of Evidence: C)
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C. On-site cardiac surgical backup
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Cardiac surgical backup for PCI has evolved from the formal surgical standby in the 1980s to an informal arrangement of first available operating room and, in some cases, off-site surgical backup (40,195–199). With the advent of intracoronary stenting, there has been a decrease in the need for emergency coronary artery bypass, ranging between 0.4 and 2% (200–202). Not surprisingly, emergency coronary artery bypass for a patient with an occluded or dissected coronary artery is associated with a higher mortality than elective surgery (203–208). Emergency procedures are also associated with high rates of perioperative infarction and less frequent use of arterial conduits. Complex CAD intervention, hemodynamic instability, and prolonged time to reperfusion are contributing factors to the increased risk of emergency bypass surgery.
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1. Primary PCI without on-site cardiac surgery
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Although thrombolytic trials demonstrated that early reperfusion saves myocardium and reduces mortality (209–212), the superiority and greater applicability of primary PCI for the treatment of acute MI has raised the question of whether primary PCI should be performed at institutions with diagnostic cardiac catheterization laboratories that do not perform elective PCI or have on-site cardiac surgery. For this reason, the establishment of PCI programs at institutions without on-site cardiovascular surgery has been promoted as necessary to maintain quality of care (195–197,213–220). In those patients where there is a contraindication to thrombolytic therapy, or when there are complications such as cardiogenic shock, catheter-based therapy may limit infarct size (221,222). It must be realized that PCI in the early phase of an acute MI can be difficult and requires even more skill and experience than routine PCI in the stable patient. The need for an experienced operator and experienced laboratory technical support (223) with availability of a broad range of catheters, guidewires, stents, and other devices (e.g., IABP) that are required for optimum results in an acutely ill patient is of major importance (Table 15). If these complex patients are treated by interventionalists with limited experience at institutions with low volume, then the gains of early intervention may be lost because of increased complications. In such circumstances, transfer to a center that routinely performs complex PCI will often be a more effective and efficient course of action (16). Thrombolysis is still an acceptable form of therapy (224) and is preferable to acute PCI by an inexperienced team (224,225).
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Table 16 Patient Selection for Angioplasty and Emergency Aortocoronary Bypass at Hospitals Without On-Site Cardiac Surgery
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Reports of emergency primary angioplasty programs from hospitals without established open-heart surgery or elective angioplasty, similar to those of most tertiary centers, have demonstrated generally favorable results. Such acceptable clinical results have been reported with intensive training, continuous oversight, and the combination of nearby, readily available bypass surgery support, a team of highly experienced interventionalists and support staff, and careful patient selection (214). However, poor results of similar endeavors are rarely reported. Before the use of stenting and glycoprotein receptor blockers, primary angioplasty in certain hospitals has been associated with acute mortality rates greater than those reported from centers with established primary angioplasty programs. Overall, in-hospital mortality rates have ranged from 1.4 to 13% (196,197,216).
Criteria have been suggested for the performance of primary PCI at hospitals without on-site cardiac surgery (Tables 15 and 16). Of note, large-scale registries have shown an inverse relationship between the number of primary angioplasty procedures performed and in-hospital mortality (226–228). The data suggest that both door-to-balloon time and in-hospital mortality are significantly lower in institutions performing a minimum of 36 primary angioplasty procedures per year (229). Communities may identify a unique qualified and experienced center wherein the on-site intervention for acute MI could be performed. Suboptimal results may relate to operator/staff inexperience and capabilities and delays in performing angioplasty for logistical reasons (230). From clinical data and expert consensus, the Committee recommends that primary PCI for acute MI performed at hospitals without established elective PCI programs should be restricted to those institutions capable of performing a requisite minimum number of primary angioplasty procedures (36/year) with a proven plan for rapid and effective PCI as well as rapid access to cardiac surgery in a nearby facility (193) (Table 17).
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2. Elective PCI without on-site surgery
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Technical improvements in interventional cardiology have led to the development of elective angioplasty programs without on-site surgical coverage. Several centers have reported satisfactory results based on careful case selection with well-defined arrangements for immediate transfer to a surgical program (195–199,231–235). The studies of angioplasty without on-site surgical coverage have not identified significant differences in the outcomes, recalling the infrequent rate of complications (236). Despite many reported successful angioplasty series without on-site surgical backup and a very low percentage need for off-site surgery in failed angioplasty, some clinicians have expressed concern (237,238) about the appropriateness of elective angioplasty in centers without on-site surgical coverage. Caution is warranted before endorsing an unrestricted policy for PCI in hospitals without appropriate facilities. Several outstanding and critically important clinical issues, such as timely management of ischemic complications, adequacy of specialized post-interventional care, logistics for managing cardiac surgical or vascular complications and operator/laboratory volumes, and accreditation must be addressed. Mere convenience should not replace safety and efficacy in establishing an elective PCI program without on-site surgery.
At this time, the Committee, therefore, continues to support the recommendation that elective PCI should not be performed in facilities without on-site cardiac surgery (Table 17). As with many dynamic areas in interventional cardiology, these recommendations may be subject to revision as clinical data and experience increase.
Recommendations for PCI With and Without On-Site Cardiac Surgery (Table 17)
Class I - Patients undergoing elective PCI in facilities with on-site cardiac surgery. (Level of Evidence: B)
- Patients undergoing primary PCI in facilities with on-site cardiac surgery. (Level of Evidence: B)
Class IIb - Patients undergoing primary PCI in facilities without on-site cardiac surgery, but with a proven plan for rapid access (within 1 h) to a cardiac surgery operating room in a nearby facility with appropriate hemodynamic support capability for transfer. The procedure should be limited to patients with ST-segment elevation MI or new LBBB on ECG, and done in a timely fashion (balloon inflation within 90 ± 30 min of admission) by persons skilled in the procedure (75 PCIs/year) (193) and only at facilities performing a minimum of 36 primary PCI procedures per year (229). (Level of Evidence: B)
Class III - Patients undergoing elective PCI in facilities without on-site cardiac surgery. (Level of Evidence: C)
- Patients undergoing primary PCI in facilities without on-site cardiac surgery and without a proven plan for rapid access (within 1 h) to a cardiac surgery operating room in a nearby facility with appropriate hemodynamic support capability for transfer or when performed by lower skilled operators (<75 PCIs/year) in a facility performing <36 primary PCI procedures/year. (Level of Evidence: C)
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V. Indications
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A broad spectrum of clinical presentations exists wherein patients may be considered candidates for PCI, ranging from asymptomatic to severely symptomatic or unstable, with variable degrees of jeopardized myocardium. Selection of appropriate candidates for PCI in a variety of clinical presentations is reviewed in this section.
Each time that a patient is considered for revascularization, the potential risk and benefits of the particular procedure under consideration must be weighed against alternative therapies (Table 18).
When PCI is considered, the benefits and risks of surgical revascularization and medical therapy always deserve thoughtful discussion with the patient and family. The initial simplicity and associated low morbidity of PCI as compared to surgical therapy is always attractive, but the patient and family must understand the limitations inherent in current PCI procedures, including a realistic presentation of the likelihood of restenosis and the potential for incomplete revascularization as compared with CABG surgery. In patients with CAD who are asymptomatic or have only mild symptoms, the potential benefit of antianginal drug therapy along with an aggressive program of risk reduction must also be understood by the patient before a revascularization procedure is performed.
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A. Asymptomatic or mild angina
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In the previous ACC/AHA Guidelines for PTCA, specific recommendations were made separately for patients with single- or multivessel disease (16,98). The current techniques of PCI have matured to the point where, in patients with favorable anatomy, the competent practitioner can perform either single- or multivessel PCI at low risk and with a high likelihood of initial success. For this reason, in this revision of the Guidelines, recommendations will be made largely based upon the patients’ clinical condition, specific coronary lesion morphology and anatomy, LV function, and associated medical conditions, and less emphasis will be placed on the number of lesions or vessels requiring PCI. The CCS Class of angina (I to IV) is used to define the severity of symptoms. The categories described in this section refer to an initial PCI procedure in a patient without prior CABG surgery. The randomized trials comparing PTCA and medical therapy have been discussed (Table 11).
The Committee recognizes that the majority of patients with asymptomatic ischemia or mild angina should be treated medically. The published ACIP study (176) casts some doubt on the wisdom of medical management for those higher-risk patients who are asymptomatic or have mild angina, but have objective evidence by both treadmill testing and ambulatory monitoring of significant myocardial ischemia and CAD. In addition, there is a substantial portion of the middle and older age populations in this country that remains physically active, participating in sports, such as tennis and skiing, or performing regular and vigorous physical exercise, such as jogging, who have CAD. For such individuals with moderate or severe ischemia and few symptoms, revascularization with PCI or CABG surgery may reduce their risk of serious or fatal cardiac events. For this reason, patients in this category of higher-risk asymptomatic ischemia or mild symptoms and severe anatomic CAD are placed in Class I or II. Percutaneous coronary intervention may be considered if there is a high likelihood of success and a low risk of morbidity or mortality. The judgment of the experienced physician is deemed valuable in assessing the extent of ischemia.
Recommendations for PCI in Asymptomatic or Class I Angina Patients (Table 19)
Class I - Patients who do not have treated diabetes with asymptomatic ischemia or mild angina with 1 or more significant lesions in 1 or 2 coronary arteries suitable for PCI with a high likelihood of success and a low risk of morbidity and mortality. The vessels to be dilated must subtend a large area of viable myocardium (108) (Table 20). (Level of Evidence: B)
Class IIa - The same clinical and anatomic requirements for Class I, except the myocardial area at risk is of moderate size or the patient has treated diabetes. (Level of Evidence: B)
Class IIb - Patients with asymptomatic ischemia or mild angina with 3 coronary arteries suitable for PCI with a high likelihood of success and a low risk of morbidity and mortality. The vessels to be dilated must subtend at least a moderate area of viable myocardium. In the physician’s judgment, there should be evidence of myocardial ischemia by ECG exercise testing, stress nuclear imaging, stress echocardiography or ambulatory ECG monitoring, or intracoronary physiologic measurements. (Level of Evidence: B)
Class III - Patients with asymptomatic ischemia or mild angina who do not meet the criteria as listed under Class I or Class II and who have:
- Only a small area of viable myocardium at risk.
- No objective evidence of ischemia.
- Lesions that have a low likelihood of successful dilation.
- Mild symptoms that are unlikely to be due to myocardial ischemia.
- Factors associated with increased risk of morbidity or mortality.
- Left main disease.
- Insignificant disease <50%. (Level of Evidence: C)
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B. Angina Class II to IV or unstable angina
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Many patients with moderate or severe stable angina or unstable angina do not respond adequately to medical therapy and often have significant coronary artery stenoses that are suitable for revascularization with CABG surgery or PCI. In addition, a proportion of these patients have reduced LV systolic function, which places them in a group that is known to have improved survival with CABG surgery and possibly with revascularization by PCI (178,179,240,241). In nondiabetic patients with 1- or 2-vessel disease in whom angioplasty of 1 or more lesions has a high likelihood of initial success, PCI is the preferred approach. In a minority of such patients, CABG surgery may be preferred, particularly for those in whom the left anterior descending coronary artery can be revascularized with the internal mammary artery or in those with left main coronary disease. In patients with unstable angina or non–Q-wave MI, intensive medical therapy should be initiated prior to revascularization with PCI or CABG surgery (242–244).
Clinical investigations evaluating the use of routine catheterization and PCI for patients with unstable angina and NSTEMI (non–ST-segment elevation MI) have yielded inconsistent results. TIMI-IIIB was the first to compare strategies of routine catheterization and revascularization in addition to medical therapy and selective use of aggressive treatment. In TIMI-IIIB, there was no difference in the incidence of death or recurrent MI at 1 year between the 2 strategies, but patients treated by the aggressive strategy experienced less angina and repeat hospitalizations for ischemia and required fewer medications (245). In the VANQWISH trial performed by the Veterans Administration, no difference in death or death and MI was observed between the two strategies at late follow-up, but the minority of patients in the aggressive strategy received revascularization, and the mortality rate for those having CABG was high (246). The FRISC II trial compared medical and revascularization approaches among patients after 6 days of low molecular weight heparin therapy before a decision regarding PCI (247). Those randomized to the conservative therapy only underwent PCI if they had 3 mm ST depression on stress testing. Compared with prior studies, patients assigned to the aggressive strategy in FRISC II experienced a 22% reduction (p = 0.031) in the incidence of death or MI at 6 months (9.4%) compared to conservatively treated patients (12.1%). In addition, there was a significant decrease in MI rate alone and a non-significantly lower mortality rate in the treated group (1.9% vs. 2.9%; p = 0.10). Symptoms of angina and hospital readmission were decreased 50% by the invasive strategy. These findings were supported by long-term follow-up from the FRISC II study indicating that low-molecular-weight heparin and early intervention lowered the risk of death, MI, and revascularization in unstable coronary syndromes, at least during the first 1 month of therapy. Early protective therapy could be used to lower the risk of late events in patients waiting for definitive PCI (248). This treatment benefit was most pronounced for high-risk patients. The FRISC II trial (247) results support the use of catheterization and revascularization for selected patients with an acute coronary syndrome. The Treat Angina with Aggrastat and determine the Cost of Therapy with an Invasive or Conservative Strategy (TACTICS) Trial randomized 2,220 patients to an early invasive strategy in which cardiac catheterization and revascularization were performed 4 to 48 h after randomization or to a conservative strategy in which revascularization was reserved for those patients who developed recurrent ischemia after medical stabilization. All patients were treated with aspirin, heparin, beta-blockers, cholesterol-lowering therapy, and tirofiban. The primary end point, a composite of death, MI, and rehospitalization for worsening chest pain by 6 months, was lower in patients assigned to the invasive strategy (15.9% vs. 19.4% in patients assigned to conservative therapy; p = 0.0025). The rate of death or MI was also significantly reduced at 6 months in the invasive strategy arm (7.3% vs. 9.5% in patients assigned to conservative therapy; p < 0.05) (249). These promising results have not yet undergone peer review and have not been published.
The indications for coronary angiography are summarized in the ACC/AHA Coronary Angiography Guidelines (194), and recommendations for PCI are summarized in the ACC/AHA Unstable Angina Guidelines (250). Indications for PCI for patients with angina Class II to IV, unstable angina, or non–Q-wave infarction follow.
Recommendations for Patients with Moderate or Severe Symptoms (Angina Class II to IV, Unstable Angina or Non–ST-Elevation MI) With Single- or Multivessel Coronary Disease on Medical Therapy (Table 21)
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Table 21 Recommendations for PCI in Moderate or Severe Symptomatic, Class II–IV Angina, Unstable Angina, or Non–ST-Elevation MI Patients
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Class I - Patients with 1 or more significant lesions in 1 or more coronary arteries suitable for PCI with a high likelihood of success and low risk of morbidity or mortality (Tables 6 and 8). The vessel(s) to be dilated must subtend a moderate or large area of viable myocardium and have high risk (Table 20). (Level of Evidence: B)
Class IIa - Patients with focal saphenous vein graft lesions or multiple stenoses who are poor candidates for reoperative surgery. (Level of Evidence: C)
Class IIb - Patient has 1 or more lesions to be dilated with reduced likelihood of success (Table 6) or the vessel(s) subtend a less than moderate area of viable myocardium. Patients with 2- or 3-vessel disease, with significant proximal LAD CAD and treated diabetes or abnormal LV function. (Level of Evidence: B)
Class III - Patient has no evidence of myocardial injury or ischemia on objective testing and has not had a trial of medical therapy, or has
- Only a small area of myocardium at risk.
- All lesions or the culprit lesion to be dilated with morphology with a low likelihood of success.
- A high risk of procedure-related morbidity or mortality. (Level of Evidence: C)
- Patients with insignificant coronary stenosis (e.g., <50% diameter). (Level of Evidence: C)
- Patients with significant left main CAD who are candidates for CABG. (Level of Evidence: B)
It is recognized by the Committee that the assessment of risk of unsuccessful PCI or serious morbidity or mortality must always be made with consideration of the alternative therapies available for the patient, including more intensive or prolonged medical therapy or surgical revascularization (Table 22) , especially in patients with unstable angina pectoris.
When CABG surgery is a poor option because of high risk due to special considerations or other organ system disease, patients otherwise in Class IIb may be appropriately managed with PCI. Under these special circumstances formal surgical consultation is recommended.
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C. Myocardial infarction
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The results of randomized clinical trials of intravenous thrombolysis and subsequent management strategies of immediate, delayed, and deferred PCI have established the benefits of early pharmacologic and mechanical reperfusion therapies for patients with acute MI (209,210,251–256).
Acute MI results from a severe and sudden cessation of myocardial blood flow, most commonly due to atherosclerotic-thrombotic occlusion of a major epicardial coronary artery. Percutaneous coronary intervention is a very effective method for re-establishing coronary perfusion and is suitable for 90% of patients. Considerable data support the use of PCI for patients with acute MI (257,258). Reported rates of achieving TIMI 3 flow, the goal of reperfusion therapy, range from 70 to 90% (259). Late follow-up angiography demonstrates that 87% of infarct arteries remain patent (260). Although most evaluations of PCI have been in patients who are eligible to receive thrombolytic therapy, considerable experience supports the value of PCI for patients who may not be suitable for thrombolytic therapy due to an increased risk of bleeding (261).
Intracoronary stents appear to augment the results of PCI for MI (Table 23). Preliminary results suggest that stenting achieves a better immediate angiographic result with a larger arterial lumen, less reclosure of the infarct-related artery, and fewer subsequent ischemic events than PTCA alone (262–264). Results from a randomized clinical trial suggest that stenting enhances late clinical outcomes (reduction in composite end point attributable to a decrease in target-vessel revascularization) when compared to PTCA alone (264). However, an increase in mortality at 1 year among the stent group has been reported in the Stent-PAMI trial (265).
Primary PTCA performed without routine stenting has been compared to thrombolytic therapy in several randomized clinical trials. These investigations consistently demonstrate that PTCA-treated patients experience less recurrent ischemia or infarction than those treated by thrombolysis (266–269). Trends favoring a survival benefit with PTCA are noted. The most recent and largest single trial (1,138 patients) demonstrated significant benefit in the composite end point death, recurrent MI, or disabling stroke at 30 days favoring angioplasty, although this benefit was not sustained at 6 months (260,270). Two meta-analyses showed superiority of PCI over thrombolysis for mortality with risk reductions of 0.34 and 0.56 (271,272). It is important to note that these results of PCI have been achieved in medical centers with experienced providers and under circumstances where angioplasty can be performed immediately following patient presentation (Fig. 3).
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Figure 3 Mortality at the end of study in all the trials comparing primary percutaneous transluminal coronary angioplasty (PTCA) with thrombolytic drug treatment. The rates for each study are grouped by thrombolytic drug regimen. The odds ratio with 95% confidence intervals (CIs) are plotted on the right. Tests for homogenity: streptokinase trials, p = 0.08; tissue-type plasminogen activator (t-PA) trials, p = 0.33; accelerated t-PA trials, p = 0.21; thrombolytic regiment, p = 0.96; and overall; p = 0.24. Percentages are pooled results and odds ratios calculated by exact method using all trials. CI = confidence interval; PTCA = percutaneous transluminal coronary angioplasty. Reproduced with permission from Weaver WD, et al. JAMA 1997;278:2093–8 (272). Reference numbers within the figure correspond to the original article.
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1. PCI in thrombolytic-ineligible patients
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Randomized, controlled clinical trials evaluating the outcome of PCI for patients who present with ST-segment elevation but who are ineligible for thrombolytic therapy and for patients who experience infarction without ST-segment elevation have not been performed. Nevertheless, there is a general consensus that PCI is an appropriate means for achieving reperfusion in patients who cannot receive thrombolytics because of increased risk of hemorrhage. Other reasons also exclude acute MI patients from thrombolytic therapy, and the outcome of PCI in these patients may differ from those eligible for lytic therapy. For example, patients who present without ST-elevation are more often older and female and have higher in-hospital mortality than those with ST-segment elevation. Little data are available to characterize the value of primary PCI for this subset of acute MI patients (261) (Table 24).
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2. Post-thrombolysis PCI
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In asymptomatic patients, the strategies of routine PCI of the stenotic infarct-related artery immediately after successful thrombolysis show no benefit with regard to salvage of jeopardized myocardium or prevention of reinfarction or death. In some studies this approach was associated with increased incidence of adverse events, which include bleeding, recurrent ischemia, emergency coronary artery surgery, and death (279–282). Routine PCI immediately after thrombolysis may increase the chance for vascular complications at the catheterization access site and hemorrhage into the infarct-related vessel wall (282).
Spontaneous recurrent ischemia and reinfarction have been observed to occur in approximately 15 to 25% of thrombolytic-treated patients (131,254,283). The majority of spontaneous cardiac ischemic events occur within the first 24 to 48 h following treatment with thrombolytic therapy and are associated with an increase in-hospital morbidity and mortality (284–286). Patients at risk for recurrent ischemia tend to be older and have more anterior infarcts. Some thrombolytic-treated patients |
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