The American College of Cardiology (ACC), the American Heart Association (AHA) and the American College of Physicians–American Society of Internal Medicine (ACP–ASIM) have developed recommendations for the management of chronic stable angina. The new guidelines encourage physicians to take advantage of proven therapies that now are often underutilized. The complete guidelines are published in the June 1999 issue of the Journal of the American College of Cardiology, and the executive summary of the guidelines is published in the June 7, 1999 issue of Circulation. The document is also available on the ACC Web site (http://www.acc.org) and the AHA Web site (http://www.americanheart.org).

The recommendations are divided into four sections that cover diagnosis, risk stratification, treatment and follow-up. Each recommendation is assigned a rank for the weight of the evidence. The highest rank is A, which signifies that the data were derived from multiple randomized clinical trials of a large number of patients. An intermediate rank of B denotes data derived from a limited number of randomized trials of a small number of patients or from careful analyses of nonrandomized studies or observational registries. The lowest rank of evidence, C, was assigned when expert consensus was the primary basis for the recommendation.

As is customary with ACC/AHA recommendations, classifications of I, II and III were used to categorize the recommendations according to the weight of the evidence. The three classifications are defined as follows:

Class I—Evidence and/or general agreement that a given procedure or treatment is useful and effective.

Class II—Conflicting evidence and/or a divergence of opinion exists about the usefulness/efficacy of a procedure or treatment. Class IIa—The weight of evidence/opinion is in favor of usefulness/efficacy. Class IIb—Usefulness/efficacy is less well-established by evidence/opinion.

Class III—Evidence and/or general agreement that the procedure/treatment is not useful/effective and in some cases may be harmful.

The following excerpt is from the sections on diagnosis, treatment and follow-up:

Recommendations Related to the Diagnosis of Angina

Recommendations for history and physical examination. Class I—In patients presenting with chest pain, a detailed symptom history, focused physical examination and directed risk factor assessment should be performed. With this information, the clinician should estimate the probability (i.e., low, intermediate or high) of significant coronary artery disease (level of evidence: B).

Recommendations for initial laboratory tests for diagnosis. Class I—(1) Hemoglobin (level of evidence: C); (2) Fasting glucose (level of evidence: C); (3) Fasting lipid panel (level of evidence: C).

Recommendations for electrocardiography (ECG), chest radiograph or computed tomography for diagnosis. Class I—(1) Rest ECG in patients without an obvious noncardiac cause of chest pain (level of evidence: B); (2) Rest ECG during an episode of chest pain (level of evidence: B); (3) Chest radiograph in patients with signs or symptoms of congestive heart failure, valvular heart disease, pericardial disease or aortic dissection/aneurysm (level of evidence: B).

Class IIa—Chest radiograph in patients with signs or symptoms of pulmonary disease (level of evidence: B).

Class IIb—(1) Chest radiograph in other patients (level of evidence: C); (2) Computed tomography (level of evidence: B).

Recommendations for exercise ECG for the diagnosis of obstructive coronary artery disease. Class I—Patients with an intermediate pretest probability of coronary artery disease based on age, gender and symptoms, including those with complete right bundle-branch block or less than 1 mm of ST depression at rest (exceptions are listed in classes II and III; level of evidence: B).

Class IIa—Patients with suspected vasospastic angina (level of evidence: C).

Class IIb—(1) Patients with a high pretest probability of coronary artery disease by age, gender and symptoms (level of evidence: B); (2) Patients with a low pretest probability of coronary artery disease by age, gender and symptoms (level of evidence: B); (3) Patients taking digoxin with ECG baseline ST-segment depression of less than 1 mm (level of evidence: B); (4) Patients with ECG criteria for left ventricular hypertrophy and less than 1 mm of baseline ST-segment depression (level of evidence: B).

Class III—(1) Patients with pre-excitation (Wolff-Parkinson-White) syndrome, electronically paced ventricular rhythm, more than 1 mm of ST depression at rest or complete left bundle-branch block (level of evidence: B for each condition); (2) Patients with an established diagnosis of coronary artery disease due to prior myocardial infarction or on coronary angiography; however, testing can assess functional capacity and prognosis (level of evidence: B).

Recommendations for echocardiography for the diagnosis of the cause of chest pain in patients with suspected angina. Class I—(1) Patients with a systolic murmur suggestive of aortic stenosis and/or hypertrophic cardiomyopathy (level of evidence: C); (2) Evaluation of extent (severity) of ischemia (e.g., left ventricular segmental wall-motion abnormality) when the echocardiogram can be obtained during pain or within 30 minutes after its abatement (level of evidence: C).

Class IIb—Patients with click and/or murmur to diagnose mitral valve prolapse (level of evidence: C).

Class III—Patients with a normal ECG, no history of myocardial infarction and no signs or symptoms suggestive of heart failure, valvular heart disease or hypertrophic cardiomyopathy (level of evidence: C).

The section on diagnosis also includes recommendations for the use of cardiac stress imaging and coronary angiography.

Recommendations for Drug Therapy

Recommendations for drug therapy to prevent myocardial infarction and death and to reduce symptoms in patients with angina. Class I—(1) Aspirin in the absence of contraindications (level of evidence: A); (2) Beta-adrenergic blockers as initial therapy in the absence of contraindications in patients with a prior myocardial infarction (level of evidence: A); (3) Beta blockers as initial therapy in the absence of contraindications in patients without prior myocardial infarction (level of evidence: B); (4) Calcium antagonists (except short-acting dihydropyridine calcium antagonists) and/or long-acting nitrates as initial therapy when beta blockers are contraindicated (level of evidence: B); (5) Calcium antagonists and/or long-acting nitrates in combination with beta blockers when initial therapy with beta blockers is not successful (level of evidence: B); (6) Calcium antagonists and/or long-acting nitrates as a substitute for beta blockers if initial treatment with beta blockers leads to unacceptable side effects (level of evidence: C); (7) Sublingual nitroglycerin or nitroglycerin spray for the immediate relief of angina (level of evidence: C); (8) Lipid-lowering therapy in patients with documented or suspected coronary artery disease and a low-density lipoprotein (LDL) cholesterol level of more than 130 mg per dL (3.35 mmol per L), with a target LDL of less than 100 mg per dL (2.60 mmol per L) (level of evidence: A).

Class IIa—(1) Clopidogrel when aspirin is absolutely contraindicated (level of evidence: B); (2) Long-acting nondihydropyridine calcium antagonists instead of beta blockers as initial therapy (level of evidence: B); (3) Lipid-lowering therapy in patients with documented or suspected coronary artery disease and an LDL level of 100 to 129 mg per dL (2.60 to 3.35 mmol per L), with a target LDL of 100 mg per dL (2.60 mmol per L) (level of evidence: B).

Class IIb—Low-intensity anticoagulation with warfarin in addition to aspirin (level of evidence: B).

Class III—(1) Dipyridamole (level of evidence: B); (2) Chelation therapy (level of evidence: B).

The treatment section of the ACC/AHA/ACP–ASIM guidelines for angina also include recommendations for the treatment of risk factors and for revascularization procedures.

Recommendations for Follow-up

Recommendations for echocardiography, treadmill exercise testing, stress imaging studies and coronary angiography during follow-up. Class I—(1) Chest radiograph for patients with evidence of new or worsening congestive heart failure (level of evidence: C); (2) Assessment of left ventricular ejection fraction and segmental wall motion in patients with new or worsening congestive heart failure or evidence of intervening myocardial infarction by history or ECG (level of evidence: C); (3) Echocardiography for evidence of new or worsening valvular heart disease (level of evidence: C); (4) Treadmill exercise testing for patients without prior revascularization who have a significant change in clinical status, are able to exercise and do not have any of the ECG abnormalities listed in number 5 (level of evidence: C); (5) Stress imaging procedures for patients without prior revascularization who have a significant change in clinical status and are unable to exercise or have one of the following ECG abnormalities: pre-excitation (Wolff-Parkinson-White) syndrome, electronically paced ventricular rhythm, more than 1 mm of ST depression at rest, and complete left bundle-branch block (level of evidence: C for each condition); (6) Stress imaging procedures for patients who have a significant change in clinical status and required a stress imaging procedure on their initial evaluation because of equivocal or intermediate-risk treadmill results (level of evidence: C); (7) Stress imaging procedures for patients with prior revascularization who have a significant change in clinical status (level of evidence: C); (8) Coronary angiography in patients with marked limitation of ordinary activity (Class III disease) despite maximal medical therapy (level of evidence: C).

Class IIb—Annual treadmill exercise testing in patients who have no change in clinical status, can exercise, have none of the ECG abnormalities listed in number 5 and have an estimated annual mortality of more than 1 percent (level of evidence: C).

Class III—(1) Echocardiography or radionuclide imaging for assessment of left ventricular ejection fraction and segmental wall motion in patients with a normal ECG, no history of myocardial infarction and no evidence of congestive heart failure (level of evidence: C); (2) Repeat treadmill exercise testing in less than three years in patients who have no change in clinical status and an estimated annual mortality of 1 percent or less on their initial evaluation as demonstrated by one of the following: low-risk Duke treadmill score without imaging or with negative results on imaging, normal left ventricular function and a normal coronary angiogram, and normal left ventricular function and insignificant coronary artery disease (level of evidence: C for each condition); (3) Stress imaging procedures for patients who have no change in clinical status and a normal rest ECG, are not taking digoxin, are able to exercise and did not require a stress imaging procedure on their initial evaluation because of equivocal or intermediate-risk treadmill results (level of evidence: C); (4) Repeat coronary angiography in patients with no change in clinical status, no change on repeat exercise testing or stress imaging, and insignificant coronary artery disease on initial evaluation (level of evidence: C).

In discussing follow-up of patients with stable angina, the guidelines state that five questions must be answered as follows:

1. Has the patient decreased the level of physical activity since the last visit?

2. Have the patient's anginal symptoms increased in frequency and become more severe since the last visit? (If the symptoms have worsened or the patient has decreased physical activity to avoid precipitating angina, then he or she should be evaluated and treated.)

3. How well is the patient tolerating therapy?

4. How successful has the patient been in reducing modifiable risk factors and improving his or her knowledge about ischemic heart disease?

5. Has the patient developed any new comorbid illnesses or has the severity of treatment of known comorbid illnesses worsened the patient's angina?