Complications of exercise and pharmacologic stress tests: Differences in younger and elderly patients

Background. Age characteristics of patients undergoing various types of str ess tests are important because of differences in clinical background and e xercise performance between the young and elderly. Adverse effects of pharm acologic agents are known to be more common in the elderly, who are less ab le to perform vigorous exercise stress testing. We investigated the clinica l background, performance characteristics, and complication rate of various stress tests in younger (less than or equal to 75 years old) and elderly ( >75 years old) patient populations. Methods. A total of 3412 patients (2796 younger, 616 elderly) underwent 5 t ypes of stress tests with (1) technetium-99m sestamibi (MIBI) single photon emission computed tomography: symptom-limited exercise (Ex, 1598 younger, 173 elderly), (2) dipyridamole infusion (0.14 mg/kg/min, 4 minutes) without exercise (D, 260 younger, 114 elderly), (3) with exercise (DEx, 339 younge r, 112 elderly), (4) adenosine infusion (0.14 mg/kg/min, 5 minutes) without exercise (A, 253 younger, 101 elderly), and (5) with exercise (AEx, 346 yo unger, 116 elderly). Results. Sixty-seven percent of patients in the younger population were abl e to achieve 85% of the maximum predicted heart rate, whereas 54% of the el derly reached this level of exercise. No patient had life-threatening compl ications. In both the younger and elderly groups, chest discomfort, feeling s of impending syncope, flushing, and fall in blood pressure occurred less frequently in DEx than D and in AEx than A. Sinus bradycardia occurred less frequently in AEx than A in the younger (1.2% vs 4.3%, P < .05) and elderl y groups (0.9% vs 6.9%, P < .05). Atrioventricular block was less frequent in AEx than A in the younger group (3.2% vs 7.9%, P < .05) but not so in th e elderly group (13.0% vs 17.8%, not significant). The frequency of ischemi c electrocardiographic changes in DEx and AEx was very similar to that of E x in both the younger and elderly groups, although ischemic electrocardiogr aphic changes in D and A are known to be less frequent. Conclusion. Of the elderly group who were judged to be fit to exercise to 8 5% of maximum predicted heart rate, nearly half failed to reach this level. In contrast, the younger patients were able to achieve this level in 67% o f tests. Supplementation with modest exercise reduced most of the pharmacol ogically related adverse effects. The elderly group was not protected from atrioventricular block as effectively as the younger group by additional ex ercise in the adenosine stress test. Ischemic electrocardiographic changes in the pharmacologic stress test were as frequent as in the exercise stress test when modest supplementary exercise was added to the pharmacologic pro tocol. There mere no deaths, myocardial infarction, or other major complica tions. These observations suggest that exercise and pharmacologic stress te sts are safe in the elderly, including those patients more than 75 pears ol d.