Angina Pectoris

A clinical syndrome of CAD caused by myocardial ischemia and characterized by dyspnea, precordial discomfort, pressure, or pain, typically precipitated by exertion and relieved by rest or sublingual nitroglycerin.

Symptoms, Signs, and Diagnosis

Among the elderly, dyspnea on exertion is a more common manifestation of myocardial ischemia than is chest pain. Exertional dyspnea results from a transient increase in left ventricular end-diastolic pressure caused by ischemia superimposed on reduced ventricular compliance.

Typically, chest pain occurs as tightness, heaviness, or constricting, pressing, squeezing, strangling, or burning discomfort in the substernal or adjacent area of the chest. The discomfort may be confined to the chest, or associated aching may be felt in one or both shoulders and arms (especially the ulnar aspect of the left upper arm) and in the fingers (particularly on the left side). Aching may also be felt in the neck, jaws, teeth, or left interscapular region. A choking sensation in the throat may be felt.

Anginal pain is less likely to be retrosternal in elderly than in younger patients and thus is more likely to be misinterpreted. Anginal pain in the back and shoulders may be misinterpreted as due to degenerative joint disease, and burning postprandial epigastric pain may be misinterpreted as due to peptic ulcer disease or a hiatus hernia. Some elderly patients underreport anginal pain because of confusion or dementia.

Anginal symptoms may be precipitated by exertion, emotional stress, heavy meals, or exposure to cold weather, wind, or tobacco smoke. For the elderly, exertion is a less common precipitant because their physical activity tends to be limited. The pain, which lasts 1 to 15 minutes, can usually be relieved within 3 minutes by use of sublingual nitroglycerin, by rest, or by resolution of emotional stress.

Anginal attacks vary in frequency from several a day to occasional attacks separated by symptom-free intervals of weeks or months. Attacks may increase in frequency (a phenomenon called crescendo angina), often leading to death, or they may gradually decrease or disappear if adequate collateral circulation develops, if the ischemic area becomes infarcted, or if heart failure supervenes and limits activity.

In stable angina, the characteristics of angina are usually constant. Unstable angina refers to any worsening in the pattern of symptoms--increased frequency, intensity, or duration of episodes; reduced threshold of stimulus; or occurrence when the patient is sedentary or awakening from sleep. Such changes may be prodromal to acute MI. In the elderly, acute pulmonary edema not due to acute MI may be a manifestation of unstable angina.

Treatment

Stable angina: The physician should identify and correct reversible factors that can aggravate myocardial ischemia and angina, such as anemia, infection, obesity, hyperthyroidism, hyperlipidemia, uncontrolled hypertension, arrhythmias (eg, atrial fibrillation with a rapid ventricular rate), and severe valvular aortic stenosis. Smokers should be advised to stop smoking. An exercise program can improve exercise tolerance. Aspirin 160 to 325 mg daily reduces the incidence of MI, stroke, and cardiovascular death.

Nitrates prevent and relieve angina. Nitroglycerin as a sublingual tablet (0.3 to 0.6 mg) or as a sublingual spray (0.4 mg) is the drug most commonly used to relieve an acute anginal attack. Onset of action is 2 to 5 minutes, and duration of action is 10 to 30 minutes. Initiating nitrate therapy at a low dose and increasing the dose slowly are important.

Long-acting nitrates help prevent recurrent episodes of angina. Isosorbide dinitrate 5 to 40 mg po bid or tid is commonly used. Onset of action is 15 to 30 minutes, and duration of action is 3 to 6 hours. Other commonly used long-acting nitrates include isosorbide mononitrate 5 to 60 mg po bid and transdermal nitroglycerin 5 to 15 mg as 2% ointment applied directly to the skin or in a skin patch. When long-acting nitrates are used, a 12- to 14-hour nitrate-free interval every 24 hours is necessary to prevent tolerance.

Hypovolemia, use of concomitant vasodilator therapy, impaired venous valves, and an impaired baroreceptor reflex make the elderly more susceptible to the hypotensive effects of nitrates. Episodes of hypotension may cause symptoms ranging from light-headedness to syncope and are commonly precipitated by standing. Patients should be instructed to sit or lie down when they take the drug sublingually.

-Blockers are effective in preventing myocardial ischemia. Propranolol 10 to 40 mg qid, extended-release propranolol 40 to 240 mg once daily, timolol 10 to 20 mg bid, metoprolol 25 to 100 mg bid, extended-release metoprolol 50 to 200 mg once daily, atenolol 25 to 100 mg once daily, and labetalol 100 to 600 mg bid are commonly used. Because metoprolol and atenolol are relatively more cardioselective than propranolol, they are less likely to induce bronchospasm and peripheral arterial vasoconstriction when given in low doses. These two drugs also cause less sedation. When sedation or depression is a concern, nadolol may be preferable because it has the least central nervous system penetration. Patients with both heart failure and angina may be treated with carvedilol 3.125 to 25 mg bid.

A nondihydropyridine calcium channel blocker (eg, verapamil 40 to 120 mg tid, extended-release verapamil 120 to 240 mg daily, diltiazem 30 to 90 mg tid, extended-release diltiazem 120 to 300 mg daily) should be used if nitrates and -blockers are contraindicated in, are poorly tolerated by, or do not control anginal symptoms in patients who have a normal left ventricular ejection fraction. If patients with persistent angina have heart failure or an abnormal left ventricular ejection fraction, amlodipine 2.5 to 10 mg daily or felodipine 2.5 to 20 mg daily should be used.

Revascularization is recommended if angina persists and interferes with quality of life or if noninvasive studies or the clinical picture indicates that the patient is at high risk (despite optimal therapy with nitrates, -blockers, and calcium channel blockers). Cardiac catheterization, which has greater risks for the elderly, is used to evaluate the need for coronary revascularization by percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG).

Unstable angina: About 90% of elderly patients can be stabilized with medical management. Care of elderly patients does not differ substantially from that of younger patients. After initiation of treatment in the emergency department, patients should be admitted to a coronary care unit. Reversible factors causing unstable angina (eg, anemia, hyperthyroidism) should be identified and corrected. When hospitalized, the elderly are prone to certain problems (eg, intensive care unit psychosis), and care should be taken to prevent these problems. Oxygen therapy should be guided by arterial saturation; it is unlikely to help if oxygen saturation exceeds 94%.

Unless contraindicated, aspirin 160 to 325 mg should be given at admission and a daily dose continued indefinitely to reduce the risk of MI and death. The first dose should be chewed to facilitate the rapid antiplatelet effect of aspirin. Ticlopidine 250 mg bid or clopidogrel 75 mg daily may be used if aspirin is contraindicated. Use of tirofiban or abciximab (given with aspirin and heparin) may also reduce the incidence of coronary events.

For patients with pain at rest, ST-T wave changes of myocardial ischemia, and no contraindications for anticoagulation, continuous IV heparin should be started and maintained for at least 48 hours.

Patients whose symptoms are not fully relieved with three sublingual nitroglycerin tablets should be given continuous IV nitroglycerin for at least 24 hours. After patients have been angina-free for 24 hours, they can be switched to oral or transdermal long-acting nitrates.

-Blockers, unless contraindicated, should be started in the emergency department. They are given IV initially, then orally.

Revascularization should be considered for patients who continue to have angina 30 minutes after initiation of therapy, who have angina that recurs during hospitalization, or who have unstable angina plus major ischemic complications (eg, pulmonary edema, complex ventricular arrhythmias, cardiogenic shock). Such patients are at increased risk of MI or cardiac death, and emergency coronary angiography should be performed to determine if PTCA or CABG is needed. Insertion of an intra-aortic balloon pump is necessary for some patients.