Prognostic stratification of obese patients by stress ^99mTc- tetrofosmin myocardial perfusion imaging

Obesity is a major heath problem associated with increased cardiovascular mortality. There are currently no data to support a role for stress imaging techniques in the risk stratification of obese patients. The aim of this study was to assess the independent value of stress ^99mTc-tetrofosmin SPECT in predicting mortality and hard cardiac events in obese patients. Methods: We studied 265 patients with a body mass index greater than 30 kg/m² by exercise or dobutamine stress ^99mTc-tetrofosmin myocardial perfusion tomography. Endpoints during follow-up were cardiac death and death of any cause. Results: The mean patient age (±SD) was 59 ± 10 y, and 110 of the patients were men (42%). The mean body mass index was 37 ± 7 kg/m². Scan findings were normal in 113 patients (43%). Myocardial perfusion abnormalities were fixed in 62 patients (23%) and reversible in 90 patients (34%). During a mean follow-up period of 5.5 ± 2 y, 41 patients (15%) died. Death was considered cardiac in 22 patients (8%). Nonfatal myocardial infarction occurred in 20 patients (7.5%). The annual cardiac death rate was 0.6% in patients with normal perfusion and 3.3% in patients with abnormal perfusion. Patients with a multiple-vessel distribution of abnormalities had a higher cardiac death rate than did patients with a single-vessel distribution (4.1%vs. 2.5%, P < 0.05). The annual mortality rate was 1.3% in patients with normal perfusion and 4.2% in patients with abnormal perfusion. In a multivariate analysis, perfusion abnormalities were independently predictive of cardiac mortality (risk ratio, 3.2; 95% confidence interval, 1.5-6.7) and overall mortality (risk ratio, 2.7; 95% confidence interval, 1.4-4.3). Conclusion: Stress ^99mTc-tetrofosmin myocardial perfusion imaging is a useful tool for predicting cardiac and overall mortality in obese patients.