In Reply

Abstract

Dr. RuDusky raises some interesting and important issues regarding the general utility of stress-testing, particularly stress-scintigraphy, for older patients. He feels that stress testing in older people is usually unnecessary for proper diagnosis and treatment and that cardiac stress-scintigraphy is highly overutilized and abused. As support for his statements, Dr. RuDusky cites studies that demonstrate limited utility of stress testing for predicting severe coronary artery disease (CAD)1 and for risk stratification of patients after an acute coronary event2, 4 or before noncardiovascular surgery.5 He concludes that rather than unnecessary and excessive care (i.e., stress testing), what “the (typical older) patient needs is a doctor.” I certainly agree with Dr. RuDusky that unnecessary or indiscriminate use of anydiagnostic or therapeutic procedure cannot be justified in our present economic climate. Indeed, the physician's critical role is to utilize astute clinical judgment to determine which patient needs which procedure. My review was meant to summarize the existing literature on stress testing of older patients and not to encourage inappropriate application of this technology. I do believe there are several situations that warrant stress testing in older patients, three of which are listed below. In general these situations involve patients who have an intermediate pretest risk of the endpoint in question; it is in such patients that Bayes’ theorem predicts the test result will have the greatest impact in moving into either a low risk or a high risk category.6 . The diagnosis of CAD in an older patient with atypical chest pain. In such a setting, the high (84%) sensitivity and reasonable (70%) specificity of the standard exercise ECG (per Table 1 of my review) can be used to facilitate appropriate patient management. A negative exercise ECG with normal exercise tolerance would argue against severe CAD and thus against any further workup. A positive test, on the other hand, suggests the need for further cardiac workup or medical therapy for presumed CAD, depending on the clinical situation. . The screening of an older asymptomatic individual before entering a vigorous exercise training program. In this setting, the pretest risk of CAD is relatively low; thus, a negative exercise ECG effectively rules out significant CAD, providing reassurance to the patient and physician regarding the safety of exercise training. In addition, the test allows the accurate prescription of the appropriate starting exercise intensity for the training program. An ischemic ST segment response, especially if 2mm or greater or occurring at a low workload, warrants further diagnostic testing and modification or abandonment of the original exercise program. . For risk stratification of patients with known CAD after an acute ischemic event, i.e., myocardial infarction, unstable angina pectoris, or acute pulmonary edema. Several studies have shown the value of a predischarge exercise ECG in identifying a subset of postinfarction patients at high risk for subsequent CAD morbidity and mortality over the next year.7-10 A 24-hour ambulatory ECG or pharmacological stress test might be substituted for exercise testing in patients unable to exercise due to pulmonary, peripheral vascular or neuromuscular disorders. Note that in each of these three settings mentioned, the standard exercise ECG is the initial test of choice, with radionuclide or echocardiographic imaging substituted only if the exercise ECG is uninterpretable because of major resting ST-T wave changes, left bundle branch block, or digitalis therapy and in patients who are unable to exercise. Thus, I believe that stress testing, coupled with sound clinical judgment, can aid significantly in the diagnosis and risk stratification of older patients with suspected or known CAD.