ACC/SCA&I EXPERT CONSENSUS DOCUMENT
American College of Cardiology/Society for Cardiac Angiography and Interventions Clinical Expert Consensus Document on Cardiac Catheterization Laboratory Standards4,4
A report of the American College of Cardiology Task Force on Clinical Expert Consensus Documents endorsed by the American Heart Association and the Diagnostic and Interventional Catheterization Committee of the Council on Clinical Cardiology of the AHA
Thomas M. Bashore, MD, FACC, Chair, Writing Committee Member,
Eric R. Bates, MD, FACC, Writing Committee Member*,
Peter B. Berger, MD, FACC, Writing Committee Member,
David A. Clark, MD, FACC, Writing Committee Member,
Jack T. Cusma, PhD, Writing Committee Member,
Gregory J. Dehmer, MD, FACC, Writing Committee Member,
Morton J. Kern, MD, FACC, Writing Committee Member**,
Warren K. Laskey, MD, FACC, Writing Committee Member,
Martin P. O’Laughlin, MD, FACC, Writing Committee Member,
Stephen Oesterle, MD, FACC, Writing Committee Member,
Jeffrey J. Popma, MD, FACC, Writing Committee Member,
Robert A. O’Rourke, MD, FACC, Chair, Task Force Member,
Jonathan Abrams, MD, FACC, Task Force Member,
Eric R. Bates, MD, FACC, Task Force Member,
Bruce R. Brodie, MD, FACC, Task Force Member,
Pamela S. Douglas, MD, FACC, Task Force Member,
Gabriel Gregoratos, MD, FACC, Task Force Member,
Mark A. Hlatky, MD, FACC, Task Force Member,
Judith S. Hochman, MD, FACC, Task Force Member,
Sanjiv Kaul, MBBS, FACC, Task Force Member,
Cynthia M. Tracy, MD, FACC, Task Force Member,
David D. Waters, MD, FACC, Task Force Member and
William L. Winters, Jr, MD, MACC, Task Force Member
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Table of contents
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- Preamble.......2172
- Executive Summary.......2172
- The Cardiac Catheterization Laboratory Environment.......2172
- Same-Day and Outpatient Cardiac Catheterization.......2173
- QA Issues.......2173
- Procedural Issues.......2174
- Personnel Issues.......2174
- Ethical Concerns.......2174
- Imaging Equipment Issues.......2175
- Radiation Safety.......2175
- Special Concerns for the Pediatric Catheterization Laboratory.......2176
- Introduction.......2176
- Organization of Committee and Evidence Review.......2176
- Purpose of This Expert Consensus Document.......2176
- The Evolution of the Cardiac Catheterization Laboratory.......2177
- The Cardiac Catheterization Laboratory Environment.......2177
- The Cardiac Catheterization Laboratory at a Hospital With Cardiac Surgery Capability.......2178
- Patients Eligible for Invasive Cardiac Procedures.......2178
- The Cardiac Catheterization Laboratory at a Hospital Without Cardiac Surgery Capability.......2178
- Patients Eligible for Diagnostic Cardiac Catheterization at a Hospital Without Cardiac Surgery Capability.......2179
- Patients Eligible for Therapeutic Invasive Procedures at a Hospital Without Cardiac Surgery Capability.......2179
- Cardiac Catheterization and Diagnostic Procedures in the Freestanding Laboratory.......2181
- Patients Eligible for Cardiac Catheterization in a Freestanding Laboratory.......2181
- The Mobile Cardiac Catheterization Laboratory.......2181
- Candidates for Same-Day or Ambulatory Cardiac Catheterization........2181
- QA Issues in the Cardiac Catheterization Laboratory.......2183
- Clinical Proficiency.......2183
- Patient Outcomes in the Diagnostic Cardiac Catheterization Laboratory.......2183
- Rates of "Normal" Cardiac Catheterizations.......2183
- Complication Rates During Diagnostic Catheterization.......2183
- Diagnostic Accuracy and Adequacy.......2184
- The Special Case of the "Ad Hoc" PCI.......2184
- Patient Outcomes in the Interventional Cardiac Catheterization Laboratory.......2184
- Equipment Maintenance and Management.......2185
- QI Program Development.......2186
- Minimum Caseload Volumes.......2187
- Procedural Issues in the Performance of Cardiac Catheterization.......2188
- Patient Preparation.......2188
- Sedatives and Relaxants.......2188
- Prevention of Contrast "Allergy".......2188
- Patients With Renal Insufficiency.......2188
- Patients With Diabetes Mellitus.......2189
- Patients Receiving Antiplatelet or Antithrombotic Medications.......2189
- Procedural Issues.......2189
- Sterile Preparation of the Access Site and Vascular Access.......2189
- Right-Heart Catheterization During the Evaluation of Coronary Artery Disease.......2190
- The Routine Use of Temporary Pacing.......2190
- Transseptal Cardiac Catheterization and Percutaneous Balloon Mitral Valvuloplasty.......2190
- Role of Left Ventricular Puncture in the Era of Echocardiography.......2190
- Use of Provocative Agents During Diagnostic Cardiac Catheterization.......2190
- Operator Safety During Cardiac Catheterization in Patients With Communicable Diseases.......2191
- Performance Issues.......2191
- Injection of Coronary Arteries.......2191
- Angiography.......2191
- Pressure Measurement.......2192
- Measurement of Cardiac Output.......2192
- Postprocedural Issues.......2193
- Vascular Hemostasis.......2193
- Reporting of Cardiac Catheterization Results.......2193
- Personnel Issues and Laboratory Design.......2194
- Attending Physician.......2194
- Teaching Attending Physician.......2194
- Secondary Operators.......2194
- Laboratory Director.......2194
- Operating Physicians.......2195
- Cardiovascular Trainee (Fellow).......2195
- Use of Physician Extenders (Physician’s Assistants and Nurse Practitioners).......2195
- Nursing Personnel.......2196
- Non-Nursing Personnel.......2196
- Staffing Patterns.......2196
- Cardiopulmonary Resuscitation.......2197
- Suggested Space Requirements.......2197
- Ethical Concerns.......2197
- Operator Assistant’s Fees, Sharing of Fees, Fee Splitting, and Fee Fixing.......2198
- Unnecessary Services.......2198
- Self-Referral, Self-Ownership, and Self-Reporting.......2198
- Informed Consent.......2198
- Ethics of "Teaching" Diagnostic and Therapeutic Procedures.......2199
- Clinical Research Studies During Diagnostic and Interventional Cardiac Catheterization.......2199
- Imaging Issues.......2199
- Radiographic Equipment.......2200
- Generators.......2200
- X-Ray Tubes.......2200
- Image Intensifiers.......2200
- Developments in X-Ray Detectors.......2201
- Video Components.......2201
- Video Cameras.......2201
- Digital Angiography Issues.......2201
- Effects on X-Ray Requirements.......2202
- Digital Acquisition Requirements.......2202
- Digital Storage and Display.......2202
- Image Formats and Standards: The DICOM Standard.......2203
- Digital Image Resolution.......2203
- Data Compression.......2203
- Telemedicine Applications.......2204
- Quantitative Measurement Methods.......2204
- Further Developments in the DICOM Standard.......2205
- Radiation Safety Issues.......2205
- Terms for Understanding Radiation Exposure in the Cardiac Catheterization Laboratory.......2205
- Biological Risks From Radiation Exposure.......2205
- Measuring Radiation Exposure.......2206
- Minimizing Occupational Exposure.......2206
- Minimizing Radiation Exposure to the Patient.......2206
- Quality Management.......2207
- Special Concerns for the Pediatric Cardiac Catheterization Laboratory.......2207
- Differences in Goals.......2207
- Who Should Perform Catheterization in Adult Congenital Heart Disease?.......2207
- Quality Assurance Issues.......2208
- Inpatient Versus Outpatient Setting for Procedures.......2208
- Operator and Laboratory Volume.......2208
- Procedural Issues.......2209
- Premedication.......2209
- Vascular Access Issues.......2209
- Medications Used During the Procedure and Use of Anesthesia.......2209
- Procedural Performance Differences Compared With the Adult Cardiac Catheterization Laboratory.......2210
- Single-Plane Versus Biplane Angiography.......2210
- Hemodynamics.......2210
- Angiographic Acquisition Differences.......2210
- Radiation Protection and the Pregnant (or Potentially Pregnant) Patient.......2210
- Shunt Measurements.......2211
- Laboratory Personnel Issues.......2211
- Reference List.......2211
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Preamble
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This document has been developed as a Clinical Expert Consensus Document (CECD), combining the resources of the American College of Cardiology (ACC) and the Society for Cardiac Angiography and Interventions (SCA&I). It is intended to provide a perspective on the current state of cardiac catheterization and the laboratories in which these procedures are performed. Clinical Expert Consensus Documents are intended to inform practitioners, payers, and other interested parties of the opinion of the ACC concerning evolving areas of clinical practice and/or technologies that are widely available or new to the practice community. Topics chosen for coverage by expert consensus documents are so designed because the evidence base, experience with technology and/or clinical practice are not considered sufficiently well developed to be evaluated by the formal ACC/American Heart Association (AHA) Practice Guidelines process. Often the topic is the subject of considerable ongoing investigation. Thus, the reader should view the CECD as the best attempt of the ACC to inform and guide clinical practice in areas where rigorous evidence may not yet be available or the evidence to date is not widely accepted. Where feasible, CECDs include indications or contraindications. Some topics covered by CECDs will be addressed subsequently by the ACC/AHA Practice Guidelines Committee.
The Task Force on CECDs 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 to inform the writing effort. Robert A. O’Rourke, MD, FACC, Chair, ACC Task Force on Clinical Expert Consensus Documents
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Executive summary
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A. The cardiac catheterization laboratory environment.
Cardiac catheterizations are currently performed safely in hospitals with and without cardiac surgical backup. The latest information from the SCA&I lists >2,100 cardiac catheterization laboratories in the U.S. (including Puerto Rico and the Virgin Islands) (1). Of these, 72% provided on-site cardiac surgery (including 85% of those performing coronary intervention). Fifty-eight laboratories were located in nonhospital settings.
In a hospital with cardiac surgery, essentially all patients with cardiovascular disease can undergo invasive studies safely. Full support services include not only cardiovascular surgery but also vascular surgery, nephrology and dialysis, neurology, hematology, and specialized imaging services (e.g., computed tomography, magnetic resonance imaging, and ultrasound). See Table 7 for assessment of proficiency criteria for individual operators and cardiac catheterization laboratories.
In the hospital setting without cardiac surgery capability, many patients can undergo cardiac procedures safely. Exclusions for cardiac catheterization in this setting include patients with acute coronary syndromes, severe congestive heart failure, pulmonary edema due to acute ischemia, a high likelihood of severe multivessel or left main disease based on noninvasive testing, and severe left ventricular dysfunction associated with valvular disease. Certain elective therapeutic interventional procedures such as percutaneous coronary interventions (PCIs) and valvuloplasty should still be performed in facilities that provide cardiac surgical support. The ACC Competence Statement on Recommendations for the Assessment and Maintenance of Proficiency in Coronary Interventional Procedures and the ACC/AHA Guidelines for PCI Procedures (2,3) have addressed the issue of primary angioplasty for acute myocardial infarction in hospitals without cardiac surgery capability. Recent data suggest a lower mortality rate among patients undergoing primary angioplasty in higher-volume centers (4). Hospitals that perform primary angioplasty but are without on-site cardiac surgery capability must have a proven plan for rapid access (within 1 h) to a cardiac surgical operating room in a nearby facility with appropriate hemodynamic support capability for such a 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 performed/year) and only in facilities performing a minimum of 36 primary PCIs/year. In accordance with the soon-to-be-published ACC/AHA guidelines for PCI (3), this committee does not endorse the performance of elective PCI in a facility without cardiac surgery capability.
Patients are also being studied in freestanding laboratories (i.e., those that are not physically attached to the hospital). By definition a freestanding laboratory is one where quick transportation of a patient to a hospital by gurney is not possible. These patients clearly must be in stable condition and at the lowest risk for complications. It is vitally important to have mechanisms for backup and bailout in place to provide assistance should patients become unstable in this setting. Although a tertiary hospital serves as an appropriate means for providing proper oversight of a freestanding laboratory, recognized credentialing bodies approved by the local community may be able to provide appropriate oversight to ensure that all issues related to quality assurance (QA) are monitored and addressed. Interventional procedures of any kind should not be performed in a freestanding facility.
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B. Same-day and outpatient cardiac catheterization
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With the decline in risk associated with cardiac catheterization, the performance of invasive procedures in the ambulatory setting has become more popular. However, prehospitalization may still be important in patients receiving anticoagulation therapy or in those with renal failure, diabetes, or a contrast allergy. Early discharge after the procedure may also be inappropriate for certain patients, including those with a procedure-related complication or hemodynamic instability. In addition, some patients are best observed overnight if severe disease is discovered (e.g., significant left main coronary artery disease or severe aortic stenosis) or in the presence of significant comorbid diseases that increase the risk of late complications. A general scheme is presented to help determine who should be excluded from early discharge after cardiac catheterization.
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C. QA issues
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Quality assurance starts with an assessment of clinical proficiency among the operators in the cardiac catheterization laboratory. This is surely one of the most difficult elements to assess, but issues of cognitive knowledge, procedural skill, clinical judgment, and procedural outcomes are all important. QA extends to the performance of the laboratory as a whole. A continuous quality-improvement (QI) program should also be included in the laboratory’s overall design.
One measure of outcome is the number of "normal" diagnostic cardiac catheterizations performed. "Normal" in this regard refers to no disease or insignificant (<50% diameter narrowing) coronary stenoses in patients studied primarily for the identification of coronary artery lesions. It is recognized that there is a difference between coronary arteries that are completely normal and those that have insignificant luminal stenoses. It is further recognized that coronary disease is a dynamic process and that endothelial dysfunction may contribute to certain clinical syndromes. In some laboratories "normal" coronary arteries may be especially prevalent because the patient mix includes a variety of disease states where coronary disease is not the major concern such as cardiomyopathy and valvular disease. The rate of "normals" identified as either insignificant or no obvious luminal narrowing should be in the range of 20% to 27% if proper screening and baseline decision making is operative prior to the catheterization.
Outcomes related to complications for diagnostic catheterization should be very low–<1%. Diagnostic accuracy and adequacy are obviously important parameters as well, though they are rarely tracked. In the interventional cardiac catheterization laboratory the acceptable complication rates are more difficult to gauge, since measures of assessing high-risk patients have not been standardized. Major complications, (i.e., death, acute myocardial infarction, and emergency bypass surgery) from interventional procedures should be <3%.
The minimum number of studies needed to confirm adequate skills in cardiac diagnostic catheterization procedures has never been validated. Given the low risk of diagnostic catheterization, the QI system should be operative and should hold precedence over any arbitrary figures proposed in this setting. The Committee could find no data to support the prior recommendation for a minimum caseload of 150 catheterizations performed by an individual per year. A minimum interventional caseload is 75 cases/year per operator and ideally 400 cases/year for the laboratory. Because of the direct correlation between both laboratory and physician volume and outcomes, a low-volume operator (<75 cases/year) should only work in a high-volume laboratory (>600 cases/year), and even then with mentoring. Low-volume operators in any other setting should not perform interventional procedures. The minimum caseload for operators performing pediatric catheterizations has not been established by data, although a caseload of 50/year has been suggested for individual operators. Pediatric cardiac catheterization laboratories often share space with adult procedural facilities. The pediatric catheterization laboratory should perform at least 75 procedures/year.
Equipment maintenance and management remain an issue, and certain guidelines are provided. Each aspect of the radiographic system should be able to meet these performance expectations. The same is true for the physiological recorders and other specific devices used in the laboratories.
A QI program must be in place. The keys are to develop variables that reflect the quality of care, to collect these variables in a systematic manner, to have a means for statistical analysis of the results, and to develop an approach to problem solving that involves feedback on the effectiveness of the solutions. These programs should provide ongoing educational opportunities for staff as well. The Committee also strongly encourages all laboratories to participate in a national data registry to help benchmark their results and provide an ongoing system for tracking complications.
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D. Procedural issues
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Although no rigid protocol is applicable to all laboratories, certain procedural issues are worthy of comment. Patient preparation generally entails premedication with mild sedatives. During the procedure a conscious-sedation protocol should be followed.
Patients with contrast allergies should receive nonionic contrast and should be premedicated with steroids. Many laboratories also use antihistamines.
Patients with renal insufficiency should be adequately hydrated before and after the procedure. A minimal amount of radiographic contrast should be used along with biplane angiography when available. There is suggestive evidence that nonionic radiographic contrast may help reduce the incidence of nephrotoxicity. Initial studies using pretreatment with acetylcysteine are very promising for the prevention of nephrotoxicity.
Fasting patients with diabetes mellitus should receive a reduced dose of insulin on the morning of the procedure. Diabetic patients treated with metformin who have mild renal insufficiency rarely have been reported to develop profound lactic acidosis after receiving radiographic contrast. Therefore, the metformin dose should be withheld on the day of the procedure and not restarted until the creatinine is stable, usually 48 h after the procedure. Antiplatelet drugs need not be withheld before cardiac catheterization. Warfarin generally is discontinued until the international normalized ratio (INR) is <1.8. It can be reversed if necessary with vitamin K or fresh frozen plasma. Patients often undergo cardiac catheterization while receiving heparin therapy. In-laboratory activated clotting time (ACT) should be in the range of  300 s (200 to 250 s if glycoprotein IIb/IIIa inhibitors are used) during the procedure and <175 s when the catheters are removed.
Sterile preparation is mandatory for all vascular access sites. It is important for operators to wear masks, caps, and eye protection to prevent accidental operator contamination with blood.
Routine catheterizations of the right side of the heart should not be performed during diagnostic or interventional cardiac catheterizations unless specific information of clinical importance is being sought. Routine use of temporary pacemakers is also inappropriate. In an era of high-quality echocardiographic methods for assessing left ventricular function and valvular gradients, there is only an extremely rare indication for direct left ventricular puncture.
Certain provocative agents may be useful during adult cardiac catheterization. These include: 1) fluid loading to assess the hemodynamics associated with constrictive pericarditis or restrictive myocardial disease; 2) the use of afterload alteration or inotropic agents to assess maximal intraventricular gradients in hypertrophic cardiomyopathy or in patients with aortic stenosis and low output and low gradient; 3) the use of coronary vasoactive agents (especially in combination with coronary flow, pressure, or velocity measures); 4) the administration of pulmonary vasodilators in patients with elevated pulmonary vascular resistance; and 5) exercise during the procedure to assess cardiovascular hemodynamics during stress.
Proper procedural technique includes adequate injection of the coronary arteries and the use of multiple orthogonal views with appropriate radiographic angulation for visualization of the various cardiac structures. Pressure measurement requires attention to proper electrical filtering and patient respiration. Accurate measurement of cardiac output is difficult in the best of settings, and the vagaries inherent in all the available methods should be understood to interpret the results properly.
Postprocedural hemostasis is achievable by a variety of means, including manual methods, mechanical compression devices, and percutaneous closure devices. It is important to monitor the hematoma and pseudoaneurysm rate involving each method and each device used in any laboratory.
Catheterization reports should contain certain basic information, and the actual images should be kept for at least 7 years after the study.
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E. Personnel issues
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Attending physicians should be credentialed according to local standards. The laboratory director should have extensive experience (>500 procedures performed over his or her career). If interventional procedures are performed in the laboratory, the director should be board certified in interventional cardiology.
The patient consent form should note if any designees other than the attending physician are participating in the procedure. Cardiology trainees (fellows) may be primary operators with supervision. Physician extenders (physician’s assistants and nurse practitioners) can participate in cardiac catheterization procedures along with the attending physician, but they cannot be primary operators, and all clinical decision making must reside with credentialed physician operators.
Other cardiac catheterization personnel include nurse practitioners, nursing personnel, radiological or physiological technologists, and now both darkroom (if cinefilm is used) and computer specialists. All are critical professionals and should be treated as such. Continuing education should be provided for nonphysician staff.
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F. Ethical concerns
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Ethical concerns include those related both to clinical practice and to biomedical research. Rarely do interventional procedures require 2 cardiologists to be in attendance. Cardiologists should never receive an admission fee, referral fee, or other "kickback" for referring a patient to a facility; this is illegal. Collusion in fixing fees is illegal as well. Unnecessary services should never be performed or billed. Cardiologists must avoid any financial business or industry arrangements that might influence their decision to care for patients because of personal gain (5). Receipt of direct remuneration from device, catheter, or drug companies to use such products is a conflict of interest and should be avoided. Procedural information should always be presented honestly, and the collection of procedural outcome data should be systematic and standardized. Informed consent should note all participants in the procedure (physician and physician extenders) and should describe all possible procedures (including ad hoc intervention) should they become a consideration. Clinical research studies require special attention, with patient safety always overriding other aspects of any investigational protocol.
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G. Imaging equipment issues
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Radiographic equipment is now evolving after years of relatively little real change. X-ray tubes with high heat capacities have become commonplace. Image intensifiers have continued to improve, with better conversion factors, improved contrast ratios, less distortion, and better resultant spatial resolution. Image intensifiers optimized for coronary angiography may not be optimal for peripheral vascular imaging. Newer X-ray detectors, such as the flat panel devices, are being investigated as an alternative to the current image intensifier. Video cameras are slowly evolving from the standard 525 x 525 lines per video frame to 1,023 or 1,049 lines with accompanying higher resolution. The video "pickup tube" is also being replaced by charge-coupled devices (CCDs) in many systems.
Nearly all new X-ray equipment that is commercially available allows for digital angiography as cinefilm is gradually phased out. This process should be completed within the next decade. Elimination of cinefilm has many advantages, including the use of lower framing rates, freeze frames for roadmapping, immediate availability of images for final interpretation, improved image playback during the procedure, and elimination of film development, display, and storage problems. Elimination of cinefilm does not reduce the X-ray exposure per frame by much, however, as the primary source of quantum noise is in the X-ray system itself. Digital systems can reduce X-ray exposure and usage by reducing framing rates. Pulsing the fluoroscopic dose helps reduce overall X-ray exposure.
Although the DICOM (Digital Imaging and COmmunication in Medicine) standard has allowed for an acceptable format and media (the CD-ROM) for exchange of information between and among cardiac catheterization laboratories, there is still no uniform standard for short-, near-, and long-term storage. Many archival options are still being evaluated. One limitation that older laboratories face is the availability of an adequate interface that will write the DICOM standard from X-ray acquisition devices to storage and retrieval devices. Most digital cardiac systems incorporate resolutions of 512 x 512 x 8-bit deep images with the capability of acquiring 30 frames per second (fps). This results in a minimal spatial resolution in the order of 0.2 to 0.3 mm. Higher matrices such as 1,024 x 1,024 can deliver resolutions of up to 0.1 to 0.15 mm but at a marked increase in cost related to data acquisition, storage, and transmission requirements.
Data compression allows for more rapid transmission of images over lower bandwidth lines and requires less storage capacity. Although this is acceptable for many purposes, clinical errors can occur if lossy compression is used. Preliminary results from the multicenter clinical study sponsored by the ACC and the European Society of Cardiology suggests that only lossless compression (about 2:1 JPEG compression, for instance) should be used for permanent storage of data and clinical decision making. Higher compression of images may be used for nonclinical situations and certain teaching and demonstrative displays of information.
Digital imaging allows for a practical approach to telemedicine and for the widespread use of quantitative angiographic methods. Further DICOM developments will include standardized formats for physiological data such as hemodynamic and electrocardiographic (ECG) waveforms and patient record demographic and other information. Other modalities such as other radiographic procedures and intravascular ultrasound will eventually be incorporated into the standard.
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H. Radiation safety
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The use of ALARA—"as low as reasonably achievable"—doses of X-ray radiation is important. Radiation exposure may be expressed in terms of rems. Radiation injury is defined by either stochastic effects (DNA injury) or nonstochastic effects (cellular injury). The average background radiation exposure is about 0.1 rem/year. Interventional cardiologists receive another 0.004 to 0.016 rem/case. The maximum recommended exposure by the National Council on Radiation Protection and Measurement (NCRPM) is 5 rems/year for the total body. Over an individual’s lifetime, the accumulated maximum dose should be no greater than the accumulated rem exposure x age (or a maximum of 50 rems).
The risk of fatal cancer in the U.S. is about 20%. The additional risk from radiation exposure in the cardiac catheterization laboratory is about 0.04% x total cumulative rem exposure. Pregnant workers can continue to work in the cardiac catheterization laboratory if they so choose. Fetal exposure, as measured by a waist dosimeter, should be no more than 0.05 rem/month or <0.5 rem for the entire pregnancy.
Radiation exposure is measured by either X-ray film badges or transluminescent dosimeter (TLD) badges. It is recommended that these badges be worn on both the thyroid collar and under the lead apron at the waist. Ring dosimeters are rarely worn in the cardiac catheterization laboratory, even though hand exposure may be high.
X-ray scatter is reduced by minimizing the number of magnified views, using digital-only cine runs, keeping the image intensifier as close to the patient as possible, and selecting the highest kilovolt level that provides acceptable image contrast (to reduce the milliamperes generated). Most of the radiation exposure during interventional procedures comes from the extended use of fluoroscopy rather than the brief cine runs. The closer the operator is to the X-ray tube, the greater the radiation exposure (left anterior oblique [LAO] cranial views may result in up to 6 times more radiation than right anterior oblique [RAO] caudal views, for instance). Proper collimation and shielding is important to help reduce exposure. To minimize patient exposure to scatter radiation, the same rules apply, with further efforts to reduce the X-ray dose most important.
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I. Special concerns for the pediatric catheterization laboratory
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The goals in the pediatric cardiac catheterization laboratory are to define internal cardiac and vascular structures and hemodynamics. Shunts frequently require evaluation. In recent years the pediatric catheterization laboratory has become as much a therapeutic arena as a diagnostic one, with atrial septostomy, valve and vessel dilation, and stent implantation available. In some institutions, closure of intracardiac defects such as patent ductus arteriosus or atrial septal defect may be accomplished.
A pediatric cardiologist should be responsible for invasive evaluation of patients from birth to 18 years of age. Adult patients with congenital heart disease may be studied by a pediatric cardiologist, a team of adult and pediatric cardiologists working together, or an adult cardiologist with specialized training and interest in adult congenital heart disease. Complication rates in the pediatric cardiac catheterization laboratory tend to be higher than those in adult laboratories. Overall complications are about 8.8%, with major complications about 2%. Neonatal patients and those undergoing interventional procedures are at greatest risk. Informed consent is usually obtained from parents or guardians. Many diagnostic procedures can be done on an outpatient basis, although this may not be practical for a variety of reasons. Eligibility for early discharge after cardiac catheterization must consider the child’s age and size, patient or parent reliability, travel time and distance, duration of procedure, time of completion, cardiac physiology, and loss of blood. Overnight observation is often required to ensure safety.
Procedural issues in the pediatric laboratory include the use of deep sedation and even general anesthesia. Vascular access may be decidedly more challenging, although venous-only catheterization may be performed when there is an interatrial communication or by use of transseptal techniques. Biplane angiography is also more important to help visualize the cardiac structures adequately, to recognize catheter positions, and to help reduce the total radiographic contrast dosage. Heart rates in children are generally much higher than in adults, requiring higher framing rates for image acquisition (often 30 to 60 fps). Higher injection rates (up to 40 mL/s) are also useful to help define abnormal intracardiac anatomy.
The laboratory should perform a minimum of 75 pediatric cases/year. Generally, an individual cardiologist should perform at least 50 cases/year to maintain skills and reduce risk of complications. A detailed QA plan should be operative. The number of "normal" cardiac catheterizations should be zero.
Oximetry rather than indocyanine green dye methods is now used in shunt measurements. In pediatric cardiac catheterization laboratories, specialized staff should be available to ensure familiarity with the procedures performed.
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I. Introduction
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A. Organization of Committee and evidence review.
The Writing Committee consisted of acknowledged experts in cardiac catheterization representing the ACC (9 members) and the SCA&I (2 members). Both the academic and private practice sectors were represented. The document was reviewed by 3 official reviewers nominated by the ACC, the ACC Cardiac Catheterization and Intervention Committee, the Diagnostic and Interventional Catheterization Committee of the Council on Clinical Cardiology of the AHA, the SCA&I, and 12 content reviewers nominated by the Writing Committee. The document was approved for publication by the ACC Board of Trustees and the SCA&I Board of Trustees in April 2001 and endorsed by the AHA and the Diagnostic and Interventional Catheterization Committee of the Council on Clinical Cardiology of the AHA. This document will be considered current until the Task Force on CECDs revises or withdraws it from distribution.
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B. Purpose of this expert consensus document
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Cardiac catheterization settings and procedures have evolved since publication of the ACC/AHA Guidelines for Cardiac Catheterization and Cardiac Catheterization Laboratories in 1991 (5). Whereas outpatient cardiac catheterizations were infrequent then, now almost all elective diagnostic cardiac catheterizations are performed on an outpatient basis. The setting for performance of cardiac catheterizations has expanded to include not only traditional medical centers with a cardiovascular surgical program, but also community hospitals without cardiovascular surgical backup and now some freestanding laboratories. The risks associated with both diagnostic and interventional cardiac catheterization have declined so markedly that older restrictions regarding the study of even higher-risk patients deserve reassessment. Now it is rare to perform interventional procedures with an empty operating room on standby and a surgical team on full alert. Indeed, the safety of such interventional procedures is even being examined in hospital settings without cardiovascular surgical facilities. The driving forces behind some of these changes have raised concerns among the cardiology community, however, so the time seems appropriate to evaluate these potential ethical issues. Equipment is also rapidly evolving, especially in the imaging arena. With the impetus provided by the universal acceptance of the DICOM standards for cardiac angiography, cinefilm is rapidly being replaced by compact discs and computerized archiving systems. More changes, such as the expanded use of the Internet, are imminent. Furthermore, "ad-hoc" catheter revascularization is increasingly being performed immediately following the diagnostic angiographic procedure. The pediatric cardiac catheterization suite is also evolving from a purely diagnostic laboratory to an interventional laboratory.
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II. The evolution of the cardiac catheterization laboratory
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Over the last half century, cardiac catheterization laboratories have evolved from highly specialized research laboratories into heavily used procedure rooms in which an extensive array of diagnostic tests and therapeutic interventional procedures are performed on millions of patients yearly. Catheterization laboratories were first used to define the hemodynamic features of complex congenital and acquired valvular heart disease. The development of cardiopulmonary bypass expanded the potential for surgical correction in many of these patients. As surgical programs grew, catheterization laboratories likewise proliferated.
With the advent of selective coronary angiography in the late 1950s, physicians began to explore the possibility of identifying and quantifying the extent of coronary artery disease. Catheterization laboratories were few and largely limited to major academic medical centers. By the late 1960s the use of aorto-coronary bypass surgery was quickly expanding throughout the country, and the acceptance of surgical revascularization promoted the proliferation of cardiac catheterization laboratories. The decade of the 1970s was characterized by substantial improvements in imaging systems and catheterization supplies and methods. Preformed catheters, introduced by Drs. Judkins and Amplatz, facilitated safe and expeditious catheterization from the femoral route and rapidly became more popular than the brachial approach pioneered by Dr. Mason Sones. Although laboratories were disproportionately located in major medical centers with cardiac surgical programs, the improved safety and simplicity of diagnostic procedures fostered the proliferation of diagnostic laboratories in community hospitals in which cardiac surgery programs did not exist. These hospitals retained close ties to tertiary centers where patients could be easily referred or transferred for surgical procedures. During this period the National Institutes of Health funded several Myocardial Infarction Research Units (MIRUs) at select academic medical centers. It was in the context of MIRU research that the safety of cardiac catheterization in the setting of an acute myocardial infarction (MI) was first demonstrated.
The late 1970s heralded a major change in the practice of invasive cardiology. The introduction of intracoronary thrombolysis and subsequently percutaneous transluminal coronary angioplasty (PTCA) forever changed the character of the catheterization laboratory. What was previously only the setting for diagnostic testing became a therapeutic laboratory where patients with both stable and unstable coronary syndromes and valvular and congenital heart disease could be treated. The introduction of percutaneous balloon valvuloplasty procedures in the mid and late 1980s and advances in interventional procedures in the pediatric catheterization laboratory further expanded the range of therapeutic options. Because of the potential for catastrophic complications, especially with interventional procedures, these methods were appropriately confined to laboratories with immediate surgical backup.
The last time the ACC/AHA Task Force on Practice Guidelines developed a general document for cardiac catheterization laboratories (5), the majority of the workload in most laboratories consisted of diagnostic cardiac catheterization procedures. Computerized recording methods and digital angiography were considered research ventures, and most cardiac catheterization procedures were performed on inpatients. However, the use of balloon angioplasty was rapidly increasing, and the 1990s heralded the evolution of second-generation coronary therapeutic devices, including several coronary atherectomy and laser catheters, followed by the widespread use of coronary artery stents. Improvements in the quality of imaging equipment, new potent antiplatelet agents, and further improvements in coronary stent technology resulted in a high degree of safety for most interventional procedures. Furthermore, the majority of routine diagnostic cardiac catheterizations performed shifted to the outpatient setting.
Cardiac catheterization laboratories have further evolved into multipurpose facilities. Improvements in X-ray systems and the development of digital processing capabilities have facilitated "noncardiac" vascular investigations and interventions in other areas of the vascular system. At select centers, in addition to cardiac disease, cardiologists are now involved in the diagnosis and therapy of disease involving the peripheral, renal, and carotid vasculature.
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III. The cardiac catheterization laboratory environment
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Although low, the risks from invasive cardiac procedures are not zero. In addition to procedural-related complications, occasional patients will become unstable during or after the procedure. For this reason, other ancillary services (Table 1) may be necessary to support the laboratory. At present, there are three basic environments in which invasive cardiac procedures are performed: the in-hospital cardiac catheterization laboratory with cardiac surgery capability, the in-hospital laboratory without cardiac surgery capability in the same hospital, and the freestanding laboratory. Certain patient subgroups may be inappropriate for study in some of these environments. The following outlines the current laboratory environments and suggests patient populations appropriate for study in each of these settings.
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A. The cardiac catheterization laboratory at a hospital with cardiac surgery capability
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The cardiac catheterization laboratory at a hospital with cardiac surgery capability is the classical or traditional type of cardiac catheterization laboratory facility. It is located at a hospital that offers a broad range of cardiovascular services, including cardiopulmonary bypass and coronary, cardiothoracic, and vascular surgery (i.e., full support services). The presence of on-site cardiac surgery capability is the defining service because it is unlikely that a cardiac surgical program would exist in the absence of the other support services listed in Table 1. If pediatric cardiac catheterization services are provided, additional ancillary services are necessary, and the availability of on-site pediatric cardiac surgery is essential if complex congenital heart diseases in infants and children are to be studied and treated.
Fully trained personnel dedicated to the facility should staff such a laboratory. This is the only setting in which patients with poorly compensated heart failure, severe left ventricular dysfunction (ejection fraction <20%), acute coronary syndromes, or other conditions that contribute to clinical instability can be studied safely. Elective coronary interventions are best performed in this setting. Physicians should have appropriate credentials for performing both diagnostic and interventional procedures or have ready access to interventional cardiologists should an emergency arise.
Although the majority of cardiac catheterization laboratories in this category are located within the main hospital building, there may be special situations in which a mobile laboratory is used temporarily at such a hospital or where a laboratory may be in a different, but adjacent building dedicated to outpatient services. Generally, these latter situations may be considered similar to a laboratory with full support services.
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1. Patients eligible for invasive cardiac procedures at a hospital with cardiac surgery capability
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A hospital with cardiac surgery capability provides an environment in which all diagnostic and therapeutic procedures can be performed on both stable and unstable patients, provided the operators are physicians with appropriate experience, adequate cumulative procedure volumes, and satisfactory outcomes. Even though a hospital may have cardiac surgery capability and is therefore technically eligible to provide every type of invasive procedure, patients requiring less commonly performed procedures (e.g., transseptal catheterization and balloon valvuloplasty) or patients with more complex conditions (e.g., adults and children with complex congenital heart disease) may be better served by referral to a more highly specialized center.
Performance of invasive cardiac procedures in the pediatric and especially neonatal age groups requires knowledge and skills that go beyond catheter manipulations and include the management of conscious sedation, administration of intravenous (IV) fluids, regulation of body temperature, and the postprocedural care of infants and children. These issues are important to understand, not only for the physician, but also for nurses and other paramedical personnel who assist in the procedure. For these reasons, pediatric procedures should only be performed if they are within the competence of the operator and the experience of the team supporting the physician in the invasive procedure. Pediatric issues are summarized later in this document.
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B. The cardiac catheterization laboratory at a hospital without cardiac surgery capability
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The performance of diagnostic cardiac catheterization in facilities without the capability for on-site cardiac surgery is now common in the U.S. About half of the 2,014 laboratories identified in 1996 had on-site cardiac surgery capability (6). The number of surgical programs has now increased, and 72% of the 2,142 laboratories reported in 2001 have cardiac surgical programs on-site (1). Many hospitals without cardiac surgery have permanent, in-house cardiac catheterization laboratories and provide the majority of supporting services except for cardiac surgery. Although cardiac surgery is the defining service, the importance of the other services listed in Table 1 cannot be overemphasized. This is especially true in situations in which a mobile cardiac catheterization laboratory operates at a smaller rural hospital. In this setting, support services such as vascular surgery and comprehensive imaging techniques may not be available should important complications develop. It is mandatory that catheterization laboratories operating in this setting have well-defined selection and exclusion criteria and provision for identification of emergency situations requiring immediate transfer to a tertiary facility and insertion of an intra-aortic balloon pump. Written agreements should be signed with a tertiary center for the timely (<60 min) transfer and acceptance of patients in the event of a crisis. In some settings, a physician using a mobile laboratory may live in the local community and is available after the laboratory leaves to assess complications or assist in patient management. In other situations, however, the physician performing the procedure may live in a distant area and may leave the hospital after the procedure. In this latter circumstance, it is essential that local physicians and support staff have an understanding of the potential complications of cardiac catheterization and be an integral part of the management process.
It is possible for catheterization laboratories to function with high quality and safety in hospitals without a cardiac surgical program; however, services are necessarily limited.
To further ensure safety, a formal arrangement between the laboratory and a nearby institution with cardiac surgical services must be made. Regulatory authorities and third-party reimbursement agencies should demand formal documentation and periodic review of such arrangements.
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1. Patients eligible for diagnostic cardiac catheterization at a hospital without cardiac surgery capability
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Patients undergoing invasive procedures in this type of facility require a higher level of screening to avoid situations that might require urgent cardiac surgery or result in a complication that could not be managed effectively with the inherent delays encountered during transfer to another facility. Clinically, adults at the greatest risk include the very elderly (>75 years of age), those with New York Heart Association (NYHA) functional class III or IV congestive heart failure, those with acute coronary syndromes or recent MI, and those in whom noninvasive testing demonstrates severe ischemia. Patients with suspected or known left main disease, markedly reduced left ventricular function (ejection fraction <20%), or severe valvular dysfunction, especially in association with poor left ventricular performance, are also at increased risk. Patients at increased risk for vascular complications should not be studied in facilities without the capability to diagnose and surgically treat such complications should they arise. Such patients include those with known severe peripheral vascular disease, severe systolic hypertension, a bleeding diathesis, the need for continuous anticoagulant therapy, or severe obesity. Pediatric patients should not be studied. Patients receiving dialysis who may decompensate after the procedure are generally best studied at a facility with rapid access to a dialysis center.
It is not feasible to list every possible situation that could develop, but general exclusions for the performance of invasive cardiac procedures at hospitals without cardiac surgery are summarized in Table 2. It is important to emphasize that these recommendations are based on the literature and the judgment and experience of Committee members rather than extensive clinical evidence developed from outcome measures.
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2. Patients eligible for therapeutic invasive procedures at a hospital without cardiac surgery capability
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Therapeutic invasive procedures primarily consist of valvuloplasty, pericardiocentesis for tamponade, and PCIs, as well as certain procedures specific for the pediatric and adult congenital heart disease populations. In evaluating the use of these procedures at hospitals without cardiac surgery capability, it is important to consider the clinical situation for which the procedure is needed, and specifically whether it is an emergency or elective procedure. Valvuloplasty is not required on an emergency basis, and therefore it should not be performed at hospitals without full support services, including cardiac surgery. Moreover, because it requires a unique knowledge base, special equipment, and technical expertise, it is advisable to refer the patient to a regional center with experience in this technique.
In the setting of pericardial tamponade, pericardiocentesis can be a lifesaving therapeutic procedure, and the potential benefits of the procedure far outweigh the risks. Although commonly performed in catheterization laboratories as a matter of convenience, ECG- or echocardiographic-guided pericardiocentesis can be performed in other areas of the hospital. In the setting of tamponade, therefore, pericardiocentesis should be immediately available, irrespective of the hospital status. In the absence of tamponade, diagnostic pericardiocentesis only rarely provides critical clinical information but can be performed with minimal risk of ventricular puncture or coronary laceration if the pericardial effusion is sizeable. Therefore, assuming that the operator is skilled and experienced, elective pericardiocentesis for large effusions is acceptable in hospitals without immediate cardiac surgery capability. Elective procedures in patients with moderate or small pericardial effusions are better performed at hospitals in which immediate cardiac surgery is available should ventricular perforation or coronary laceration occur.
The performance of coronary angioplasty and other PCIs at hospitals without immediate surgical backup is controversial. In simple terms, patients can be divided into two groups: 1) those having the procedure as an alternative to thrombolytic therapy within 12 h from the onset of acute MI and 2) all others who are assumed to be undergoing elective or semielective procedures. In the setting of an acute MI, several small studies (7–9) have suggested that patients presenting to hospitals without cardiac surgery capability can be treated with primary angioplasty without a measurable difference in complications or outcomes when compared with hospitals with on-site cardiac surgery capability. However, these are not randomized trials, and none of these studies are of sufficient size to detect a small difference between groups. Recently reported data from the National Registry of Myocardial Infarction Investigators have revealed 28% less mortality among patients undergoing primary angioplasty in high-volume hospitals than in those undergoing the procedure in low-volume settings (4). Most hospitals without cardiac surgery capability perform a relatively low volume of cardiac interventions.
Although some studies support the use of primary angioplasty at hospitals without on-site cardiac surgery capability, important operator, laboratory, and institutional requirements must exist (9). If it is accepted that it is possible to develop a program of primary angioplasty for MI at a hospital without on-site cardiac surgery capability, the important question still remains whether this is an appropriate decision based on a desire to provide the best possible care for the local community. For example, is it really necessary to offer primary angioplasty at a hospital without cardiac surgery capability if a hospital with a cardiac surgical program is <10 min away? Although it can be argued that should an interventional complication occur, transport time and delay to a surgical center would be inconsequential, it is also appropriate to make certain that the motives for offering this service at a hospital without on-site cardiac surgery capability are not based purely on financial considerations or physician convenience. Moreover, it is unlikely that smaller hospitals performing only emergency procedures on patients with acute MI can satisfy the procedure volume requirements that now are associated with better outcomes (3,4).
In the final analysis, this Committee endorses the opinions and recommendations of the current ACC/AHA Committee revising the 1993 PTCA guidelines (3). In brief, primary angioplasty for reperfusion therapy in the setting of acute myocardial infarction in hospitals without onsite cardiac surgery capability must only be performed in a setting where there is 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 manner (balloon inflation within 90 ± 30 min of admission) by persons skilled in the procedure (those performing 75 PCIs/year) and only at facilities performing a minimum of 36 primary PCIs/ year (3). Newer thrombolytic regimens, especially those combining thrombolytic agents with glycoprotein (GP) IIb/IIIa inhibitors, have higher reperfusion rates approaching those achieved by mechanical means and could reduce this as an issue (10,11).
Although the need for swift intervention drives the argument for primary coronary intervention at hospitals without on-site cardiac surgery capability, this does not apply to elective coronary intervention. The risks of coronary intervention have diminished with the increased use of coronary artery stents and GP IIb/IIIa inhibitors. Nevertheless, complications that require urgent bypass surgery still occur, and there will always be some risk related to the transfer between hospitals of patients for whom an interventional procedure has failed. These risks, however small, must be balanced against the proven safety of performing the procedure at a hospital with on-site cardiac surgery capability. The performance of elective angioplasty in hospitals without such capability has been reported from several centers outside the U.S. (12,13) where cardiac surgery is generally less available. However, given the availability of cardiac surgery in the U.S., it seems quite unlikely that patients or their families are significantly inconvenienced by referral to a hospital with on-site cardiac surgery available. Therefore, in agreement with the upcoming ACC/AHA PCI guidelines (3), it is the opinion of this Committee that the performance of elective coronary interventions in hospitals without on-site cardiac surgery capability cannot be endorsed at this time. The Committee is aware that certain programs that do perform interventions in this setting are affiliated with a high-volume PCI/coronary artery bypass graft (CABG) center and have a well-organized plan for emergency transfer of patients, a sophisticated communication system between the primary site and the tertiary center, and a means for measuring and reporting patient complications and outcomes. Such a strictly monitored and controlled setting may allow for elective interventional procedures without cardiac surgical backup on-site, but outcomes from such programs have yet to be reported. This is obviously a dynamic area that awaits further data regarding the safety and outcomes of patients treated.
In addition, the desire for an interventional cardiac catheterization program should not be used to justify the development of a low-volume cardiac surgery program. There is concern among Committee members that low-volume cardiac surgery programs may be developed for the sole purpose of allowing an interventional cardiac catheterization program to be operative. The development of a cardiac surgery program should reflect the need based on a high volume of cardiac catheterization procedures.
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C. Cardiac catheterization and diagnostic procedures in the freestanding laboratory
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A freestanding laboratory is not physically attached to a hospital. By definition, it is a laboratory in which quick transportation of a patient to a hospital by gurney is not possible. Although some hospitals build such laboratories adjacent to their primary facility, many are privately owned, and the physicians who use the facility may also own it. In the 2001 Directory of Cardiac Catheterization Laboratories assembled by the SCA&I, 58 such laboratories submitted data (1), but this number is clearly increasing. It is the responsibility of each freestanding laboratory to have a formal relationship with at least 1 tertiary referral hospital so that a written established plan for the emergency transfer of patients is in place. Furthermore, freestanding facilities must have the necessary equipment for intubation and ventilatory support. Physicians using these facilities must be capable of performing endotracheal intubation and inserting an intra-aortic balloon pump. Appropriate QA and ongoing QI programs must be established in writing and documented. Oversight has traditionally been provided by a tertiary referral hospital, but alternatives that comply with the maintenance of the highest concern for patient care may be used if acceptable by local standards and if a well-defined QA program is operative.
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1. Patients eligible for cardiac catheterization in a freestanding laboratory
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Patients undergoing cardiac catheterization procedures in a freestanding facility require the highest level of screening to avoid situations that might require urgent cardiac surgery or result in a complication for which time spent transferring the patient to a hospital could be detrimental. All of the exclusions that apply to cardiac catheterization laboratories at hospitals without full-support services also apply to freestanding laboratories. Other patients who should not be studied in a freestanding facility include those with cardiac or comorbid conditions of such severity that the patient’s condition could potentially become unstable during or after the procedure (Table 2).
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2. The mobile cardiac catheterization laboratory
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The mobile cardiac catheterization laboratory may be located at a hospital with cardiac surgical backup, at a hospital without cardiac surgery capability, or even in a freestanding environment. These laboratories are subject to the same concerns and quality controls as those of any laboratory in the respective setting. Mobile laboratories are occasionally used as temporary facilities before completion of a fixed (permanent) laboratory. To be eligible for study in the mobile laboratory, patients must meet the same criteria as those for more traditional environments.
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D. Candidates for same-day or ambulatory cardiac catheterization
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Improvements in the safety and ease of performing invasive cardiac procedures plus the constant pressure to minimize costs have made it quite uncommon to hospitalize patients for only an invasive cardiac procedure. Indeed, for the vast majority of adult patients, a diagnostic procedure can be safely completed in an ambulatory setting. Patients should be hospitalized if their clinical condition warrants it, after which an invasive cardiac procedure may then become part of their overall management. In some isolated situations, preprocedure hospitalization is still appropriate. For example, patients who require continuous anticoagulation therapy may require hospitalization to switch safely from warfarin to heparin anticoagulation. Patients with renal insufficiency benefit from preprocedural hydration or drugs to help reduce contrast nephropathy. Patients with brittle diabetes who also require steroids to reduce the risk of contrast-allergic reactions may require prehospitalization. Preprocedural admission may also be appropriate for other situations, and the decision of the individual practitioner should be respected when it is in the best interest of the patient.
Noninvasive testing can often identify patients with high-risk coronary or valvular disease before catheterization and is helpful for identifying patients who should not be studied in settings without cardiac surgery capability. However, diagnostic studies of high-risk patients may still be initiated in the outpatient setting before referral to the appropriate settings. If, as suspected from noninvasive testing, the catheterization study confirms a high-risk anatomic situation, admission to the hospital may become necessary after the procedure.
Because of the overall safety of diagnostic procedures, patients are often discharged within 2 to 6 h of completion of the study. This applies not only to outpatients, but also to inpatients for whom a disposition is made rapidly after completion of the procedure. A general scheme for the disposition of patients after diagnostic catheterization is shown in Figure 1. Rarely, a patient will develop a procedure-related complication that requires hospitalization. More patients will require admission because of the findings from the procedure. A patient who develops a large hematoma may require a more prolonged period of bed rest and observation to ensure that the puncture site has stabilized. Patients who are found to have important left main disease should be considered for admission pending early surgical therapy or at least until it is clear that the diagnostic procedure has not caused clinical instability. Finally, some patients may require observation overnight simply because they do not have a supervised home setting. Table 3 lists possible situations for which early (<2 to 6 h) discharge after diagnostic catheterization may be unwise. These are not meant as absolute exclusion criteria prohibiting early discharge, but the practitioner should consider hospitalization when treating such patients. Based on the judgment of the physician, it would be appropriate to observe patients with 1 or more of these clinical risks for a longer period of time.
Because of the improving safety of coronary interventions and newer access techniques, such as the radial approach as well as the availability of vascular closure devices, outpatient coronary intervention may become a reality. This concept is currently being investigated. At this time it is not approved by the Committee.
Because of the simplicity and safety of diagnostic catheterization, the vast majority of patients can be discharged home within 2 to 6 h. This applies to inpatients as well as outpatients. For example, a patient may be admitted for evaluation of a prolonged episode of chest pain, but subsequent testing shows no evidence of MI. In some patients, it may be appropriate to consider coronary angiography as the first diagnostic test. If coronary angiography shows no evidence of coronary disease, the patient may be discharged 2 to 6 h after the procedure to complete evaluation as an outpatient. Patients undergoing radial artery cardiac catheterization may be discharged as early as 90 min after the procedure.
There are three basic steps in determining the appropriateness of early discharge for patients. First, a patient may require a prolonged stay if an important complication has occurred. Second, the procedure may reveal new findings for which hospitalization is indicated. Finally, appropriate care of the patient for noncardiac issues may be necessary for safety.
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IV. QA issues in the cardiac catheterization laboratory
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The modern cardiac catheterization laboratory is an amalgamation of complex, highly sophisticated medical and radiological instrumentation used in the diagnosis and management of patients with not only chronic stable disease, but also acute life-threatening illnesses. In any complex, procedure-oriented area, it is necessary to have a well-organized program of QA that focuses on individual and laboratory outcomes. In addition, a continuous program of quality improvement (QI) should be implemented to provide ongoing feedback and structure for change. The following discussion summarizes the key components of a QA program for both diagnostic and interventional cardiac catheterization laboratories. These components are: 1) clinical proficiency, 2) equipment maintenance and management, and 3) a QI process. A fourth component, radiation safety, is discussed separately later in this document.
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A. Clinical proficiency
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The assessment of clinical proficiency in the catheterization laboratory is based on a composite of cognitive skills, procedural conduct, and clinical judgment. A deficiency in any one element is enough to worsen clinical outcomes; thus, all elements must be considered. Unfortunately, there is no unique source that details "how to do things correctly." Although clinical experience is the sine qua non of proficiency, the myriad of techniques and technology preclude rigid delineation of a singular "right way." There is, however, one incontrovertible bottom line—patient outcomes.
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1. Patient outcomes in the diagnostic cardiac catheterization laboratory
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Preamble