Safety, hemodynamic profile, and feasibility of dobutamine stress technetium myocardial perfusion single-photon emission CT imaging for evaluation ofcoronary artery disease in the elderly

Objectives: Cardiovascular disease is the leading cause of morbidity and mo rtality in the elderly, The evaluation of coronary artery disease by exerci se stress testing is frequently limited by the patient's inability to exerc ise, Although pharmacologic stress testing with dobutamine is an alternativ e, the safety of dobutamine myocardial perfusion scintigraphy in the elderl y has not been previously studied. Patients and methods: We studied the safety and feasibility of dobutamine ( up to 40 mu g/kg/min)atropine (up to 1 mg) stress myocardial perfusion scin tigraphy using technetium single-photon emission CT imaging in 227 patients greater than or equal to 70 years old (mean +/- SD age,75 +/- 4 years). A control group of 227 patients < 70 years old (mean age, 55 +/- 11 years; ma tched for gender, prevalence of previous infarction, beta-blocker therapy, and severity of resting perfusion abnormalities) was studied to assess age- related differences in the safety and the hemodynamic response, A feasible test was defined as the achievement of the target heart rate and/or an isch emic end point (angina, ST-segment depression, or reversible perfusion abno rmalities). Results: No myocardial infarction or death occurred during the test. The ta rget heart rate was achieved more frequently in the elderly patients (87% v s 79%; p < 0.05), The elderly patients had a higher prevalence of supravent ricular tachycardia (7% vs 1%; p < 0.005) and premature ventricular contrac tion (74% vs 32%; p < 0.005) during the test, as compared to the younger pa tients, There was a trend to a higher prevalence of ventricular tachycardia (5% vs 2%) and atrial fibrillation (38 vs 0.4%) in the elderly patients, A rrythmias were terminated spontaneously by termination of dobutamine infusi on or by administration of metoprolol, Independent predictors of supraventr icular tachyarrhthmias and ventricular tachycardia were older age (p < 0.00 1; chi(2), 9.8) and myocardial perfusion defect score at rest (p < 0.01; ch i(2), 6.8) respectively, by using a multivariate analysis of clinical and s tress test variables. Elderly patients had a higher prevalence of systolic BP drop > 20 mm Hg during the test (37% vs 12%; p < 0.05), The test was ter minated due to hypotension in 2% of the elderly patients and in 1% of the c ontrol group. Age was the most powerful predictor of hypotension (p < 0.005 ; chi(2), 10.3). The test was considered feasible in 216 elderly patients ( 95%) and in 209 patients of the control group (92%). Conclusion: Dobutamine-atropine stress myocardial perfusion scintigraphy is a highly feasible method for the evaluation of coronary artery disease in the elderly. Elderly patients have a higher risk for developing hypotension and supraventricular tachyarrhythmias during a dobutamine stress test. How ever, dobutamine-induced hypotension is often asymptomatic and rarely neces sitates the termination of the test.