Incremental prognostic value of dobutamine–atropine stress 99mTc-tetrofosmin myocardial perfusion imaging for predicting outcome in diabetic patients with limited exercise capacity

Abstract

This study assessed the incremental value of dobutamine stress ( 99m)Tc-tetrofosmin single-photon emission computed tomography (SPECT) for the prediction of cardiac events in diabetic patients with limited exercise capacity. The study population comprised 125 consecutive diabetic patients (mean age 61+/-9 years, 61% men) who were unable to perform an exercise test and underwent dobutamine ( 99m)Tc-tetrofosmin SPECT. Follow-up was successful in 124 (99%) patients. Three patients who underwent early revascularisation (within 60 days) were excluded. End-points during follow-up were cardiac death and non-fatal myocardial infarction. An abnormal scan (with the presence of reversible or fixed perfusion defects) was observed in 76 (63%) patients. During the follow-up (3.4+/-1.5 years), 36 patients died (19 cardiac deaths) and four patients had non-fatal myocardial infarction. Cardiac death occurred in one of 49 (2%) patients with a normal myocardial perfusion study and in 18 of 75 (24%) patients with an abnormal study (p<0.001). Abnormal scan was incremental to the clinical parameters in predicting cardiac death (chi(2)=48 vs 39, p<0.05) and hard cardiac events (chi(2)=50 vs 43, p<0.05). Dobutamine stress ( 99m)Tc-tetrofosmin SPECT provides prognostic information additional to clinical data for the prediction of cardiac death and hard cardiac events in diabetic patients unable to perform an exercise test.