Myocardial Ischemia in the Asymptomatic Older Patient

Although clinically manifest CAD is present in about one-fourth of individuals older than 65 years, a like proportion of additional persons have asymptomatic coronary artery stenoses, manifest only by inducible myocardial ischemia. A major challenge to contemporary cardiology is to detect the subset of such asymptomatic subjects at highest risk for future coronary events, especially myocardial infarction and sudden death. In the BLSA, we have employed various strategies toward this goal. In apparently healthy BLSA men and women, conversion from a normal to an ischemic ST segment response to treadmill exercise testing on serial biennial visits did not improve the prediction of subsequent coronary events. However, the combination of ischemic ST segment depression and a segmental thallium-201 perfusion defect induced by treadmill exercise identified a small subset of asymptomatic older subjects, 48% of whom developed a coronary event over a 4.6 year mean follow up period. The pathophysiology, risk factors, and treatment of silent myocardial ischemia are also briefly reviewed.