Eleven-Year Prognostic Value of Dobutamine Stress 99mTc-Sestamibi Myocardial Perfusion Imaging in Patients With Limited Exercise Capacity

Abstract

Myocardial perfusion single-photon emission computed tomography is a routine technique for the evaluation of coronary artery disease. However, information on the very long term prognostic value of dobutamine stress single-photon emission computed tomographic myocardial perfusion imaging (MPI) in patients with limited exercise capacity is scarce. The aim of this study was to assess the long-term prognostic value of dobutamine stress technetium-99m (99mTc)–sestamibi MPI in these patients. The study population consisted of a high-risk cohort of 531 consecutive patients with limited exercise capacity who underwent dobutamine stress 99mTc-sestamibi MPI for the assessment of known or suspected coronary artery disease. Follow-up was successful in 528 patients. Because of early revascularization, 55 patients were excluded. The present data are based on 473 patients. The end points were all-cause mortality, cardiac death, nonfatal myocardial infarction, and late (>60 days) coronary revascularization. Kaplan-Meier survival curves were performed and univariate and multivariate analyses were performed to identify predictors of very long term outcome. The mean age of the patients was 61 ± 12 years, and 58% were men. Abnormal results (defined as the presence of reversible or fixed defects) were observed in 312 patients (66%). During a mean follow-up period of 11.3 ± 6.7 years, 287 patients (61%) died (all-cause mortality), of whom 125 (26%) died due to cardiac causes. Nonfatal myocardial infarction occurred in 59 patients (12%). Late coronary revascularization was performed in 61 patients (13%). Univariate predictors of major cardiac events included age, male gender, previous infarction, diabetes mellitus, history of angina, heart failure, ST-segment changes, abnormal results on 99mTc-sestamibi scan, reversible defect, fixed defect, summed rest score, and summed stress score. Multivariate analysis identified abnormal results on MPI as a strong independent predictor of major adverse cardiac events. In conclusion, in patients with limited exercise capacity, dobutamine stress 99mTc-sestamibi single-photon emission computed tomography provides incremental prognostic information in addition to clinical and stress test parameters for the prediction of very long term outcomes.