Introduction

A disorder in which one or more coronary arteries are narrowed by atherosclerotic plaque or vascular spasm.

Of persons >= 65, 30% have clinical manifestations of coronary artery disease (CAD). In autopsy studies, 70% of persons > 70 have CAD with >= 50% atherosclerotic obstruction of one or more coronary arteries. The prevalence of CAD and the incidence of new coronary events are higher among men than among women < 75 but are similar among men and women >= 75. CAD is the most common cause of death in persons >= 65, and 80% of deaths due to CAD occur in persons >= 65. The incidence of sudden cardiac death as the initial manifestation of CAD increases with age.

During the last 30 years in the USA, the CAD mortality rate has decreased for all geographic regions, most major sex-race groups, and all age groups > 35. Between 1968 and 1978, the CAD mortality rate decreased by 28% for persons aged 65 to 74 and by 19% for those aged 75 to 84. Between 1987 and 1994, the CAD mortality rate decreased by 5.1% per year, the incidence of recurrent myocardial infarction (MI) decreased, and post-MI survival rates increased. Furthermore, persons appear to be reaching old age with less severe atherosclerotic disease, according to recent autopsy studies. Factors contributing to the decreased severity of atherosclerosis and CAD mortality rate include reductions in cholesterol levels and in smoking prevalence as well as improved medical care for persons with acute CAD and better control of hypertension.

Risk Factors

Risk factors for CAD in elderly men and women include cigarette smoking, systolic and/or diastolic hypertension, increased pulse pressure, increased serum total and low-density lipoprotein (LDL) cholesterol levels, decreased serum high-density lipoprotein (HDL) cholesterol levels, diabetes mellitus, obesity, physical inactivity, advancing age, increased carotid intimal-medial thickness, and hyperhomocysteinemia. Hypertriglyceridemia is a risk factor for women.

Diagnosis

The diagnosis of CAD is usually based on symptoms and signs and is confirmed by angiographic evidence of significant coronary artery obstruction or by a previously documented MI. Coronary angiography is the gold standard for detecting the presence of CAD and determining its severity; noninvasive procedures (ECG, exercise testing, and echocardiography) can be used to detect myocardial ischemia.

Results of diagnostic procedures may help predict which patients are more likely to have new coronary events. Such patients include those with evidence of left ventricular hypertrophy on an ECG or an ischemic ST-segment depression of >= 0.5 mm on a resting ECG; those with electronic pacemaker rhythm, atrial fibrillation, left bundle branch block, intraventricular conduction defect, type II second-degree atrioventricular block, or complex ventricular arrhythmias; and those who, in response to exercise testing, have exercise-induced hypotension, an inadequate blood pressure response to exercise, a marked ST-segment depression (>= 2.0 mm) or an ST-segment depression in both anterior and inferior leads during exercise testing, short exercise duration (< 6 minutes using a standard Bruce treadmill protocol), an ST-segment depression that begins within 6 minutes of starting exercise, or persistence of ST-segment depression for > 8 minutes during recovery after exercise. The incidence of new coronary events is higher in elderly patients with CAD and complex ventricular arrhythmias or silent myocardial ischemia detected by 24-hour ambulatory ECG monitoring. Patients with left ventricular hypertrophy or with an abnormal left ventricular ejection fraction detected by echocardiography are at particular risk of new coronary events.

Primary Prevention

Modifiable risk factors for CAD should be controlled. Cessation of cigarette smoking, treatment of hypertension and hyperlipidemia, maintenance of a normal body weight, and regular physical activity lower the risk of CAD and new coronary events. A diet low in saturated fat and cholesterol is recommended. For obese persons, regular aerobic exercise and a healthy diet are recommended. Moderate exercise programs suitable for the elderly include walking, climbing stairs, swimming, and bicycling.

Because the incidence of coronary events is higher in the elderly than in younger persons, risk factor modification causes a greater reduction in the absolute number of coronary events in the elderly.