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J Am Coll Cardiol, 2006; 48:598-675, doi:10.1016/j.jacc.2006.05.030 © 2006 by the American College of Cardiology Foundation |
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Preamble |
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 Top Preamble I. IntroductionII. General principlesIII. Specific valve lesionsIV. Evaluation and Management...V. Management of Valvular...VI. Management of Congenital...VII. Surgical considerationsVIII. Intraoperative AssessmentIX. Management of Patients...X. Evaluation and Treatment...Appendix 1References |
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The American College of Cardiology (ACC) and the American Heart Association (AHA) have jointly engaged in the production of such guidelines in the area of cardiovascular disease since 1980. This effort is directed by the ACC/AHA Task Force on Practice Guidelines, whose charge is to develop, update, or revise practice guidelines for important cardiovascular diseases and procedures. Writing committees are charged with the task of performing an assessment of the evidence and acting as an independent group of authors to develop or update written recommendations for clinical practice.
Experts in the subject under consideration are selected from both organizations to examine subject-specific data and write guidelines. The process includes additional representatives from other medical practitioner and specialty groups where appropriate. Writing committees 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 where data exist. Patient-specific modifiers, comorbidities, and issues of patient preference that might influence the choice of particular tests or therapies are considered, as well as frequency of follow-up. When available, information from studies on cost will be considered; however, review of data on efficacy and clinical outcomes will be the primary basis for preparing recommendation in these guidelines.
The ACC/AHA Task Force on Practice Guidelines makes every effort to avoid any actual, potential, or perceived conflicts of interest that might arise as a result of an outside relationship or personal interest of a member of the writing committee. Specifically, all members of the writing committee and peer reviewers of the document are asked to provide disclosure statements of all such relationships that might be perceived as real or potential conflicts of interest. Writing committee members are also strongly encouraged to declare a previous relationship with industry that might be perceived as relevant to guideline development. If a writing committee member develops a new relationship with industry during his or her tenure, he or she is required to notify guideline staff in writing. The continued participation of the writing committee member will be reviewed. These statements are reviewed by the parent task force, reported orally to all members of the writing panel at each meeting, and updated and reviewed by the writing committee as changes occur. Please refer to the methodology manual for ACC/AHA guideline writing committees for further description of the relationships with industry policy, available on ACC and AHA World Wide Web sites (http://www.acc.org/clinical/manual/manual_introltr.htm and http://circ.ahajournals.org/manual/). Relationships with industry pertinent to these guidelines are listed in Appendixes 1 and 2 of the full-text Guidelines for members of the writing committee and peer reviewers, respectively.
These practice guidelines are intended to assist healthcare providers in clinical decision making by describing a range of generally acceptable approaches for the diagnosis, management, and prevention of specific diseases or conditions. These guidelines attempt to define practices that meet the needs of most patients in most circumstances. These guideline recommendations reflect a consensus of expert opinion after a thorough review of the available, current scientific evidence and are intended to improve patient care. If these guidelines are used as the basis for regulatory/payer decisions, the ultimate goal is quality of care and serving the patient’s best interests. The ultimate judgment regarding care of a particular patient must be made by the healthcare provider and patient in light of all of the circumstances presented by that patient. There are circumstances in which deviations from these guidelines are appropriate.
The "ACC/AHA 2006 Practice Guidelines for the Management of Patients With Valvular Heart Disease" was approved for publication by the ACC Foundation (ACCF) board of trustees in May 2006 and the AHA Science Advisory and Coordinating Committee in May 2006. The executive summary and recommendations are published in the August 1, 2006 issue of the Journal of the American College of Cardiology and the August 1, 2006 issue of Circulation. The full-text guideline is e-published in the same issues of each journal and is posted on the World Wide Web sites of the ACC (www.acc.org) and the AHA (www.americanheart.org). The guidelines will be reviewed annually by the ACC/AHA Task Force on Practice Guidelines and will be considered current unless they are updated, revised, or sunsetted and withdrawn from distribution. Copies of the full text and the executive summary are available from both organizations.
Sidney C. Smith, Jr., MD, FACC, FAHA, Chair, ACC/AHA Task Force on Practice Guidelines
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I. Introduction |
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TopPreambleI. IntroductionII. General principlesIII. Specific valve lesionsIV. Evaluation and Management...V. Management of Valvular...VI. Management of Congenital...VII. Surgical considerationsVIII. Intraoperative AssessmentIX. Management of Patients...X. Evaluation and Treatment...Appendix 1References |
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The committee emphasizes the fact that many factors ultimately determine the most appropriate treatment of individual patients with valvular heart disease within a given community. These include the availability of diagnostic equipment and expert diagnosticians, the expertise of interventional cardiologists and surgeons, and notably, the wishes of well-informed patients. Therefore, deviation from these guidelines may be appropriate in some circumstances. These guidelines are written with the assumption that a diagnostic test can be performed and interpreted with skill levels consistent with previously reported ACC training and competency statements and ACC/AHA guidelines, that interventional cardiological and surgical procedures can be performed by highly trained practitioners within acceptable safety standards, and that the resources necessary to perform these diagnostic procedures and provide this care are readily available. This is not true in all geographic areas, which further underscores the committee’s position that its recommendations are guidelines and not rigid requirements.
All of the recommendations in this guideline revision were converted from the tabular format used in the 1998 guideline to a listing of recommendations that has been written in full sentences to express a complete thought, such that a recommendation, even if separated and presented apart from the rest of the document, would still convey the full intent of the recommendation. It is hoped that this will increase the readers’ comprehension of the guidelines. Also, the level of evidence, either A, B, or C, for each recommendation is now provided. See Figure 1 for further details on the classification and level of evidence schema.
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II. General principles |
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TopPreambleI. IntroductionII. General principlesIII. Specific valve lesionsIV. Evaluation and Management...V. Management of Valvular...VI. Management of Congenital...VII. Surgical considerationsVIII. Intraoperative AssessmentIX. Management of Patients...X. Evaluation and Treatment...Appendix 1References |
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A heart murmur may have no pathological significance or may be an important clue to the presence of valvular, congenital, or other structural abnormalities of the heart. Most systolic heart murmurs do not signify cardiac disease, and many are related to physiological increases in blood flow velocity. In other instances, a heart murmur may be an important clue to the diagnosis of undetected cardiac disease that may be important even when asymptomatic or that may define the reason for cardiac symptoms. In these situations, various noninvasive or invasive cardiac tests may be necessary to establish a firm diagnosis and form the basis for rational treatment of an underlying disorder. Echocardiography is particularly useful in this regard, as discussed in the "ACC/AHA/ASE 2003 Guidelines for the Clinical Application of Echocardiography" (1). Diastolic murmurs virtually always represent pathological conditions and require further cardiac evaluation, as do most continuous murmurs. Continuous "innocent" murmurs include venous hums and mammary souffles.
1. Electrocardiography and Chest Roentgenography
Although echocardiography usually provides more specific and often quantitative information about the significance of a heart murmur and may be the only test needed, the electrocardiogram (ECG) and chest X-ray are readily available and may have been obtained previously. The absence of ventricular hypertrophy, atrial enlargement, arrhythmias, conduction abnormalities, prior myocardial infarction, and evidence of active ischemia on the ECG provides useful negative information at a relatively low cost. Abnormal ECG findings in a patient with a heart murmur, such as ventricular hypertrophy or a prior infarction, should lead to a more extensive evaluation that includes echocardiography.
Chest roentgenograms often yield qualitative information on cardiac chamber size, pulmonary blood flow, pulmonary and systemic venous pressure, and cardiac calcification in patients with cardiac murmurs. When abnormal findings are present on chest X-ray, echocardiography should be performed.
2. Echocardiography
Class I
Although echocardiography can provide important information, such testing is not necessary for all patients with cardiac murmurs and usually adds little but expense in the evaluation of asymptomatic younger patients with short grade 1 to 2 midsystolic murmurs and otherwise normal physical findings. At the other end of the spectrum are patients with heart murmurs for whom transthoracic echocardiography proves inadequate. Depending on the specific clinical circumstances, transesophageal echocardiography (TEE), cardiac magnetic resonance, or cardiac catheterization may be indicated for better characterization of the valvular lesion.
It is important to note that Doppler ultrasound devices are very sensitive and may detect trace or mild valvular regurgitation through structurally normal tricuspid and pulmonic valves in a large percentage of young, healthy subjects and through normal left-sided valves (particularly the mitral valve [MV]) in a variable but lower percentage of patients (2–6).
General recommendations for performing echocardiography in patients with heart murmurs are provided. Of course, individual exceptions to these indications may exist.
3. Cardiac Catheterization
Cardiac catheterization can provide important information about the presence and severity of valvular obstruction, valvular regurgitation, and intracardiac shunting. It is not necessary in most patients with cardiac murmurs and normal or diagnostic echocardiograms, but it provides additional information for some patients in whom there is a discrepancy between the echocardiographic and clinical findings. Indications for cardiac catheterization for hemodynamic assessment of specific valve lesions are given in Section III, "Specific Valve Lesions." Specific indications for coronary angiography to screen for the presence of coronary artery disease (CAD) are given in Section X-B.
4. Exercise Testing
Exercise testing can provide valuable information in patients with valvular heart disease, especially in those whose symptoms are difficult to assess. It can be combined with echocardiography, radionuclide angiography, and cardiac catheterization. It has a proven track record of safety, even among asymptomatic patients with severe aortic stenosis (AS). Exercise testing has generally been underutilized in this patient population and should constitute an important component of the evaluation process.
5. Approach to the Patient
The evaluation of the patient with a heart murmur may vary greatly depending on the timing of the murmur in the cardiac cycle, its location and radiation, and its response to various physiological maneuvers. Also of importance is the presence or absence of cardiac and noncardiac symptoms and other findings on physical examination that suggest the murmur is clinically significant.
Echocardiography is indicated for patients with diastolic or continuous heart murmurs not due to a cervical venous hum or a mammary souffle during pregnancy, for those with holosystolic or late systolic murmurs, for those with midsystolic murmurs of grade 3 or greater intensity, and for those with softer systolic murmurs in whom dynamic cardiac auscultation suggests a definite diagnosis (e.g., hypertrophic cardiomyopathy). Echocardiography is also indicated in certain patients with grade 1 or 2 midsystolic murmurs, including patients with symptoms or signs consistent with infective endocarditis, thromboembolism, heart failure, myocardial ischemia/infarction, or syncope.
It must be re-emphasized that trivial, minimal, or physiological valvular regurgitation, especially affecting the mitral, tricuspid, or pulmonic valves, is detected by color flow imaging techniques in many otherwise normal patients, including many patients who have no heart murmur at all (2,5,6). This observation must be considered when the results of echocardiography are used to guide decisions in asymptomatic patients in whom echocardiography was used to assess the significance of an isolated murmur.
Characteristics of innocent murmurs in asymptomatic adults that have no functional significance include the following:
Throughout these guidelines, treatment recommendations will often derive from specific echocardiographic measurements of left ventricular (LV) size and systolic function. Accuracy and reproducibility are critical, particularly when applied to surgical recommendations for asymptomatic patients with mitral regurgitation (MR) or aortic regurgitation (AR). Serial measurements over time, or reassessment with a different imaging technology (radionuclide ventriculography or cardiac magnetic resonance), are often helpful for counseling individual patients. Lastly, although handheld echocardiography can be used for screening purposes, it is important to note that its accuracy is highly dependent on the experience of the user. The precise role of handheld echocardiography for the assessment of patients with valvular heart disease has not been elucidated.
As valuable as echocardiography may be, the basic cardiovascular physical examination is still the most appropriate method of screening for cardiac disease and will establish many clinical diagnoses. Echocardiography should not replace the cardiovascular examination but can be useful in determining the cause and severity of valvular lesions, particularly in older and/or symptomatic patients.
B. Valve Disease Severity Table. Classification of the severity of valve disease in adults is listed in Table 1. The classification for regurgitant lesions is adapted from the recommendations of the American Society of Echocardiography (7). For full recommendations of the American Society of Echocardiography, please refer to the original document. Subsequent sections of the current guidelines refer to the criteria in Table 1 to define severe valvular stenosis or regurgitation.
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1. Endocarditis Prophylaxis
Class I
Prophylaxis against infective endocarditis is recommended for the following patients:
Prophylaxis against infective endocarditis is not recommended for the following patients:
*Patients with MVP without regurgitation require additional clinical judgment. Indications for antibiotic prophylaxis in MVP are discussed in Section III-E-2. Patients who do not have MR but who do have echocardiographic evidence of thickening and/or redundancy of the valve leaflets, and especially men 45 years of age or older, may be at increased risk for infective endocarditis (10). Additionally, approximately one third of patients with MVP without MR at rest may have exercise-induced MR (11). Some patients may exhibit MR at rest on one occasion and not on another. There are no data available to address this latter issue, and at present, the decision must be left to clinical judgment, taking into account the nature of the invasive procedure, the previous history of endocarditis, and the presence or absence of valve thickening and/or redundancy.
2. Rheumatic Fever Prophylaxis
Class I
Patients who have had an episode of rheumatic fever are at high risk of developing recurrent episodes of acute rheumatic fever. Patients who develop carditis are especially prone to similar episodes with subsequent attacks. Secondary prevention of rheumatic fever recurrence is thus of great importance. Continuous antimicrobial prophylaxis has been shown to be effective. Anyone who has had rheumatic fever with or without carditis, including patients with mitral stenosis (MS) should receive prophylaxis for recurrent rheumatic fever (12).
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III. Specific valve lesions |
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TopPreambleI. IntroductionII. General principlesIII. Specific valve lesionsIV. Evaluation and Management...V. Management of Valvular...VI. Management of Congenital...VII. Surgical considerationsVIII. Intraoperative AssessmentIX. Management of Patients...X. Evaluation and Treatment...Appendix 1References |
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1. Grading the Degree of Stenosis
For these guidelines, we graded AS severity on the basis of a variety of hemodynamic and natural history data (Table 1) (7,20), using definitions of aortic jet velocity, mean pressure gradient, and valve area as follows:
2. Natural History
The natural history of AS in the adult consists of a prolonged latent period during which morbidity and mortality are very low. The rate of progression of the stenotic lesion has been estimated in a variety of invasive and noninvasive studies (21). Once even moderate stenosis is present (jet velocity greater than 3.0 m per second; Table 1), the average rate of progression is an increase in jet velocity of 0.3 m per second per year, an increase in mean pressure gradient of 7 mm Hg per year, and a decrease in valve area of 0.1 cm2 per year (22–27); however, there is marked individual variability in the rate of hemodynamic progression. Although it appears that the progression of AS can be more rapid in patients with degenerative calcific disease than in those with congenital or rheumatic disease (27–29), it is not possible to predict the rate of progression in an individual patient. For this reason, regular clinical follow-up is mandatory in all patients with asymptomatic mild to moderate AS. In addition, progression to AS may occur in patients with aortic sclerosis, defined as valve thickening without obstruction to LV outflow (30).
Aortic sclerosis is present in approximately 25% of adults over 65 years of age and is associated with clinical factors such as age, sex, hypertension, smoking, serum low-density lipoprotein and lipoprotein(a) levels, and diabetes mellitus (31). Aortic sclerosis on echocardiography in subjects without known coronary disease is also associated with adverse clinical outcome, with an approximately 50% increased risk of myocardial infarction and cardiovascular death compared with subjects with a normal aortic valve (32–34). The mechanism of this association is unclear and is likely related to subclinical atherosclerosis, endothelial dysfunction, or systemic inflammation rather than valve hemodynamics.
Eventually, symptoms of angina, syncope, or heart failure develop after a long latent period, and the outlook changes dramatically. After the onset of symptoms, average survival is 2 to 3 years (35–39), with a high risk of sudden death. Thus, the development of symptoms identifies a critical point in the natural history of AS. It is important to emphasize that symptoms may be subtle and often are not elicited by the physician in taking a routine clinical history.
Sudden death is known to occur in patients with severe AS and, in older retrospective studies, has been reported to occur without prior symptoms (35,40–42). However, in prospective echocardiographic studies, sudden death in previously asymptomatic patients is rare (20,27,38,43–45), estimated at less than 1% per year when patients with known AS are followed up prospectively.
3. Management of the Asymptomatic Patient
Asymptomatic patients with AS have outcomes similar to age-matched normal adults; however, disease progression with symptom onset is common (20,27,38,43–47). Patients with asymptomatic AS require frequent monitoring for development of symptoms and progressive disease.
a. Echocardiography (Imaging, Spectral, and Color Doppler) in Aortic Stenosis
Class I
b. Exercise Testing
Class IIb
Exercise testing should not be performed in symptomatic patients because of the high risk of complications; however, in asymptomatic patients, exercise testing is relatively safe and may provide information that is not uncovered during the initial clinical evaluation (20,46–52). When the medical history is unclear, exercise testing can identify a limited exercise capacity, abnormal blood pressure responses, or even exercise-induced symptoms (46,47,52). An abnormal hemodynamic response (e.g., hypotension or failure to increase blood pressure with exercise) in a patient with severe AS is considered a poor prognostic finding (46,53). Finally, in selected patients, the observations made during exercise may provide a basis for advice about physical activity. Exercise testing in asymptomatic patients should be performed only under the supervision of an experienced physician, with close monitoring of blood pressure and the ECG.
c. Serial Evaluations
The frequency of follow-up visits to the physician depends on the severity of AS and on the presence of comorbid conditions. An essential component of each visit is patient education about the expected disease course and symptoms of AS. Patients should be advised to promptly report the development of any change in exercise tolerance, exertional chest discomfort, dyspnea, lightheadedness, or syncope.
Serial echocardiography is an important part of an integrated approach that includes a detailed history, physical examination, and, in some patients, a carefully monitored exercise test. Because the rate of progression varies considerably, clinicians often perform an annual echocardiogram on patients known to have moderate to severe AS. Serial echocardiograms are helpful to assess changes in stenosis severity, LV hypertrophy, and LV function. Therefore, in patients with severe AS, an echocardiogram every year may be appropriate. In patients with moderate AS, serial studies performed every 1 to 2 years are satisfactory, and in patients with mild AS, serial studies can be performed every 3 to 5 years. Echocardiograms should be performed more frequently if there is a change in signs or symptoms.
d. Medical Therapy
Antibiotic prophylaxis is indicated in all patients with AS for prevention of infective endocarditis and, in those with rheumatic AS, for prevention of recurrent rheumatic fever. Patients with associated systemic arterial hypertension should be treated cautiously with appropriate antihypertensive agents. With these exceptions, there is no specific medical therapy for patients who have not yet developed symptoms. Patients who develop symptoms require surgery, not medical therapy.
There are no medical treatments proven to prevent or delay the disease process in the aortic valve leaflets; however, the association of AS with clinical factors similar to those associated with atherosclerosis and the mechanisms of disease at the tissue level (15–19,30–34,54–58) and small retrospective studies of the effect of lipid-lowering therapy (59–64) have led to the hypothesis that intervention may be possible to slow or prevent disease progression in the valve leaflet (56,65). Yet, a prospective, randomized, placebo-controlled trial in patients with calcific aortic valve disease failed to demonstrate a benefit of atorvastatin in reducing the progression of aortic valve stenosis over a 3-year period (66). It is noteworthy that the patients in this study had high levels of aortic valve calcification by computed tomography and evidence of moderate to severe AS at baseline. Thus, further trials in patients with less severe aortic valve calcification, with longer follow-up periods, are needed. In the meanwhile, evaluation and modification of cardiac risk factors is important in patients with aortic valve disease to prevent concurrent CAD.
e. Physical Activity and Exercise
Recommendations for physical activity are based on the clinical examination, with special emphasis on the hemodynamic severity of the stenotic lesion. Recommendations on participation in competitive sports have been published by the Task Force on Acquired Valvular Heart Disease of the 36th Bethesda Conference (67). Physical activity is not restricted in asymptomatic patients with mild AS; these patients can participate in competitive sports. Patients with moderate to severe AS should avoid competitive sports that involve high dynamic and static muscular demands. Other forms of exercise can be performed safely, but it is advisable to evaluate such patients with an exercise test before they begin an exercise or athletic program.
4. Indications for Cardiac Catheterization
Class I
The pressure gradient across a stenotic valve is related to the valve orifice area and the transvalvular flow (68). Thus, in the presence of depressed cardiac output, relatively low pressure gradients may be obtained in patients with severe AS. On the other hand, during exercise or other high-flow states, significant pressure gradients can be measured in minimally stenotic valves. For these reasons, complete assessment of AS requires measurement of transvalvular flow, determination of the mean transvalvular pressure gradient, and calculation of the effective valve area. Attention to detail with accurate measurements of pressure and flow is important, especially in patients with low cardiac output or a low transvalvular pressure gradient.
5. Low-Flow/Low-Gradient Aortic Stenosis
Class IIa
In selected patients with low-flow/low-gradient AS and LV dysfunction, it may be useful to determine the transvalvular pressure gradient and to calculate valve area during a baseline state and again during exercise or low-dose pharmacological (i.e., dobutamine infusion) stress, with the goal of determining whether stenosis is severe or only moderate in severity (51,70–76). Such studies can be performed in either the echocardiography or the cardiac catheterization laboratory. If a dobutamine infusion produces an increment in stroke volume and an increase in valve area greater than 0.2 cm2 and little change in gradient, it is likely that the baseline evaluation overestimated the severity of stenosis. In contrast, patients with severe AS will have a fixed valve area with an increase in stroke volume and an increase in gradient. These patients are likely to respond favorably to surgery. Patients in whom stroke volume fails to increase with dobutamine (less than 20% increase) appear to have a very poor prognosis with either medical or surgical therapy (1,77).
Dobutamine stress testing in patients with AS should be performed only in centers with experience in pharmacological stress testing and with a cardiologist in attendance.
6. Indications for Aortic Valve Replacement
Class I
In adults with severe, symptomatic, calcific AS, AVR is the only effective treatment. Younger patients with congenital or rheumatic AS may be candidates for valvotomy (see Section VI-A-2). Although there is some lack of agreement about the optimal timing of surgery in asymptomatic patients, it is possible to develop rational guidelines for most patients. A proposed management strategy for patients with severe AS is shown in Figure 2 (78). Particular consideration should be given to the natural history of asymptomatic patients and to operative risks and outcomes after surgery. See also Section VII-A.
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b. Asymptomatic Patients
Although AVR is associated with low perioperative morbidity and mortality in many centers, the average perioperative mortality in the Society of Thoracic Surgeons (STS) database is 3.0% to 4.0% for isolated AVR and 5.5% to 6.8% for AVR plus CABG (92,93). These rates are 33% higher in centers with low volume than in centers with the highest surgical volume (94). A review of Medicare data (95), involving 684 US hospitals and more than 142 000 patients, indicates that the average in-hospital mortality for AVR in patients over the age of 65 years is 8.8% (13.0% in low-volume centers and 6.0% in high-volume centers). In addition, despite improved longevity of current-generation bioprosthetic valves (96,97), AVR in young patients subjects them to the risks of structural valve deterioration of bioprostheses (96,98–102) and the appreciable morbidity and mortality of mechanical valves (100,102–106). Thus, the combined risk of surgery in older patients and the late complications of a prosthesis in younger patients needs to be balanced against the possibility of preventing sudden death, which, as noted above, occurs at a rate of less than 1.0% per year.
Despite these considerations, some difference of opinion persists among clinicians regarding the indications for AVR in asymptomatic patients with severe AS, because the probability of remaining free of cardiac symptoms without surgery is less than 50% at 5 years (20,27,45). Studies suggest that patients at risk of rapid disease progression and impending symptom onset can be identified on the basis of clinical and echocardiographic parameters. The rate of hemodynamic progression is faster in patients with asymptomatic severe (27) or mild to moderate (29) AS when patient age is over 50 years and severe valve calcification or concurrent CAD is present. Adverse clinical outcomes are more likely in patients with a more rapid rate of hemodynamic progression, defined as an annual increase in aortic jet velocity greater than 0.3 m per second per year or a decrease in valve area greater than 0.1 cm2 per year (20,27). The presence of LV hypertrophy by ECG and smaller aortic valve area by Doppler echocardiography predict the development of symptoms (20,45). In addition, serum levels of B-type natriuretic peptide may provide important prognostic information (107). In situations in which there is delay between symptom onset and surgical intervention, patients are at high risk of adverse outcomes during the waiting period. These higher-risk patients might warrant more frequent echocardiography or earlier consideration of valve replacement.
c. Patients Undergoing Coronary Artery Bypass or Other Cardiac Surgery
Patients with severe AS, with or without symptoms, who are undergoing CABG should undergo AVR at the time of the revascularization procedure. Similarly, patients with severe AS undergoing surgery on other valves (such as MV repair) or the aortic root should also undergo AVR as part of the surgical procedure. In patients with moderate AS, it is generally accepted practice to perform AVR at the time of CABG (108–112). However, there are no data to support a policy of AVR for mild AS at the time of CABG, with the exception of those patients with moderate to severe valvular calcification (29,108,109,112–114). Recommendations for AVR at the time of CABG are discussed in Section X-D.
7. Aortic Balloon Valvotomy
Class IIb
The indications for palliative valvotomy in patients in whom AVR cannot be recommended because of serious comorbid conditions are even less well established. Most asymptomatic patients with severe AS who require urgent noncardiac surgery can undergo surgery at a reasonably low risk with monitoring of anesthesia and attention to fluid balance (126–130). Balloon aortic valvotomy is not recommended for these patients. If preoperative correction of AS is needed, they should be considered for AVR.
8. Medical Therapy for the Inoperable Patient
Comorbid conditions (e.g., malignancy) or, on occasion, patient preferences might preclude AVR for severe AS. Under such circumstances, there is no therapy that prolongs life, and only limited medical therapies are available to alleviate symptoms. Patients with evidence of pulmonary congestion can benefit from cautious treatment with digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors. In patients with acute pulmonary edema due to AS, nitroprusside infusion may be used to reduce congestion and improve LV performance. Such therapy should be performed in an intensive care unit under the guidance of invasive hemodynamic monitoring (131). Atrial fibrillation has an adverse effect on atrial pump function and ventricular rate; if prompt cardioversion is unsuccessful, pharmacological control of the ventricular rate is essential.
9. Special Considerations in the Elderly
Because there is no effective medical therapy and balloon valvotomy is not an acceptable alternative to surgery, AVR must be considered in all elderly patients who have symptoms caused by AS. AVR is technically possible at any age (132), but the decision to proceed with such surgery depends on many factors, including the patient’s wishes and expectations. Older patients with symptoms due to severe AS, normal coronary arteries, and preserved LV function can expect a better outcome than those with CAD or LV dysfunction (133). Deconditioned and debilitated patients often do not return to an active existence, and the presence of the other comorbid disorders could have a major impact on outcome.
In addition to the confounding effects of CAD and the potential for stroke, other considerations are peculiar to older patients. For example, a narrow LV outflow tract and a small aortic annulus sometimes present in elderly women could require enlargement of the annulus. Heavy calcification of the valve, annulus, and aortic root may require debridement. Likewise, excessive or inappropriate hypertrophy associated with AS can increase the risk of perioperative morbidity and mortality, and preoperative recognition of elderly patients with marked LV hypertrophy followed by appropriate perioperative management can reduce this risk substantially. There is no perfect method for weighing all of the relevant factors and identifying specifically high- and low-risk elderly patients, but this risk can be estimated well in individual patients (88–91,134).
B. Aortic Regurgitation.
1. Acute Aortic Regurgitation
In acute severe AR, the sudden large regurgitant volume is imposed on a left ventricle of normal size that has not had time to accommodate to the volume overload. With an abrupt increase in end-diastolic volume, the ventricle operates on the steep portion of a normal diastolic pressure-volume relationship, and LV end-diastolic and left atrial pressures may increase rapidly and dramatically. The Frank-Starling mechanism is used, but the inability of the ventricle to develop compensatory chamber dilatation acutely results in a decrease in forward stroke volume. Although tachycardia develops as a compensatory mechanism to maintain cardiac output, this is often insufficient. Hence, patients frequently present with pulmonary edema and/or cardiogenic shock. Patients may also present with signs and symptoms of myocardial ischemia.
a. Diagnosis
Many of the characteristic physical findings of chronic AR are modified or absent when valvular regurgitation is acute, which can lead to underestimation of its severity. Echocardiography is indispensable in confirming the presence and severity of the valvular regurgitation, determining its cause, and determining whether there is rapid equilibration of aortic and LV diastolic pressure. Evidence for rapid pressure equilibration includes a short AR diastolic half-time (less than 300 ms), a short mitral deceleration time (less than 150 ms), or premature closure of the MV.
Acute AR caused by aortic root dissection is a surgical emergency that requires particularly prompt identification and management. TEE is indicated when aortic dissection is suspected (135–137). In some settings, computed tomographic imaging or magnetic resonance imaging should be performed if this will lead to a more rapid diagnosis than can be achieved by TEE (135,136,138). Cardiac catheterization, aortography, and coronary angiography are rarely required, are associated with increased risk, and might delay urgent surgery unnecessarily (136,139–142). Angiography should be considered only when the diagnosis cannot be determined by noninvasive imaging and when patients have known CAD, especially those with previous CABG (see Section X-B).
b. Treatment
Death due to pulmonary edema, ventricular arrhythmias, electromechanical dissociation, or circulatory collapse is common in acute severe AR, even with intensive medical management. Urgent surgical intervention is recommended. Nitroprusside, and possibly inotropic agents such as dopamine or dobutamine to augment forward flow and reduce LV end-diastolic pressure, may be helpful to manage the patient temporarily before operation. Intra-aortic balloon counterpulsation is contraindicated. Although beta blockers are often used in treating aortic dissection, these agents should be used very cautiously, if at all, in the setting of acute AR because they will block the compensatory tachycardia. In patients with acute severe AR resulting from infective endocarditis, surgery should not be delayed, especially if there is hypotension, pulmonary edema, or evidence of low output.
2. Chronic Aortic Regurgitation
AR represents a condition of combined volume overload and pressure overload (143). As the disease progresses, recruitment of preload reserve and compensatory hypertrophy permit the ventricle to maintain normal ejection performance despite the elevated afterload. The majority of patients remain asymptomatic throughout this compensated phase, which may last for decades. In many patients, however, the balance between afterload excess, preload reserve, and hypertrophy cannot be maintained indefinitely, and afterload mismatch (144) or depressed contractility ultimately results in a reduction in ejection fraction, first into the low-normal range and then below normal. Patients often develop dyspnea at this point in the natural history, and diminished coronary flow reserve may result in exertional angina. However, this transition may be much more insidious, and it is possible for patients to remain asymptomatic until severe LV dysfunction has developed.
For purposes of the subsequent discussion, patients with normal LV systolic function will be defined as those with normal LV ejection fraction at rest. It is recognized that other indices of LV function may not be "normal" in chronic severe AR and that the hemodynamic abnormalities noted above may be considerable. It is also recognized that the transition to LV systolic dysfunction represents a continuum and that there is no single hemodynamic measurement that represents the absolute boundary between normal LV systolic function and LV systolic dysfunction.
LV systolic dysfunction (defined as an ejection fraction below normal at rest) is initially a reversible phenomenon related predominantly to afterload excess, and full recovery of LV size and function is possible with AVR (145–152). With time, depressed myocardial contractility predominates over excessive loading as the cause of progressive systolic dysfunction. This can progress to the extent that the full benefit of surgical correction of AR, in terms of recovery of LV function and improved survival, can no longer be achieved (150,153–159).
a. Natural History
Asymptomatic Patients With Normal Left Ventricular Function
The current recommendations are derived from 9 published series (160–169) involving a total of 593 asymptomatic patients with initially normal LV systolic function with a mean follow-up period of 6.6 years. The rate of progression to symptoms or LV systolic dysfunction averaged 4.3% per year. Sudden death occurred in 7 of the 593 patients, an average mortality rate of less than 0.2% per year. Seven of the 9 studies reported the rate of development of asymptomatic LV dysfunction, defined as an ejection fraction at rest below normal (161–165,167,168); 37 of a total of 535 patients developed depressed systolic function at rest without symptoms during a mean 5.9-year follow-up period, a rate of 1.2% per year.
Despite the low likelihood of patients developing asymptomatic LV dysfunction, it should also be emphasized that more than one fourth of patients who die or develop systolic dysfunction do so before the onset of warning symptoms (161–163,167). Thus, thorough questioning of patients regarding symptomatic status is not sufficient in the serial evaluation of asymptomatic patients, and quantitative evaluation of LV function is also indispensable.
Asymptomatic Patients With Depressed Systolic Function
The limited data in asymptomatic patients with depressed LV ejection fraction indicate that the majority develop symptoms that warrant AVR within 2 to 3 years (170–172). The average rate of symptom onset in such patients is greater than 25% per year.
Symptomatic Patients
There are no contemporary large-scale studies of the natural history of symptomatic patients with chronic AR because the onset of angina or significant dyspnea is usually an indication for valve replacement. Data emanating from the presurgical era indicate that patients with dyspnea, angina, or overt heart failure have a poor outcome with mortality rates of greater than 10% per year in patients with angina pectoris and greater than 20% per year in those with heart failure (173–175). Similar poor outcomes have been reported in the current era in symptomatic patients who do not undergo AVR, even among those with preserved LV systolic function (166,176,177).
b. Diagnosis and Initial Evaluation
Class I
For purposes of the subsequent discussion of management of patients with AR, severe AR is defined as clinical and Doppler evidence of severe regurgitation (Table 1) in addition to LV cavity dilatation. If the patient is asymptomatic and leads an active lifestyle, and the echocardiogram is of good quality, no other testing is necessary. If the patient has severe AR and is sedentary or has equivocal symptoms, exercise testing is helpful to assess functional capacity, symptomatic responses, and hemodynamic effects of exercise (Fig. 3). If the echocardiogram is of insufficient quality to assess LV function, radionuclide angiography or cardiac magnetic resonance should be used in asymptomatic patients to measure LV ejection fraction at rest and to estimate LV volumes. In patients who are symptomatic on initial evaluation, it is reasonable to proceed directly to TEE or cardiac catheterization and angiography if the echocardiogram is of insufficient quality to assess LV function or severity of AR.
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c. Medical Therapy
Class I
Whether vasodilator therapy can prolong the compensated phase of asymptomatic patients who have volume-loaded left ventricles but normal systolic function has been investigated in only 2 studies. The first compared long-acting nifedipine versus digoxin in a prospective randomized trial (164). Over a 6-year period, fewer patients randomized to nifedipine required AVR because of symptoms or development of LV dysfunction (ejection fraction less than 0.50). This study enrolled a relatively small number of patients (143 patients); there were relatively few end points (20 patients in the digoxin group and 6 in the nifedipine group underwent AVR); and there was no placebo control group. A second study compared placebo, long-acting nifedipine, and enalapril in 95 consecutive patients, who were followed for 7 years (169). Neither nifedipine nor enalapril reduced the development of symptoms or LV dysfunction warranting AVR compared with placebo. Moreover, neither drug significantly altered LV dimension, ejection fraction, or mass over the course of time compared with placebo. Thus, definitive recommendations regarding the indications for
In 2003 the ACC/AHA Task Force on Practice Guidelines provided a list of suggested phrases to use when writing recommendations. All recommendations in this guideline have been written in full sentences that express a complete thought, such that a recommendation, even if separated and presented apart from the rest of the document (including headings above sets of recommendations), would still convey the full intent of the recommendation. It is hoped that this will increase readers’ comprehension of the guidelines and will allow queries at the individual recommendation level.
