15-Year outcome after normal exercise 99mTc-sestamibi myocardial perfusion imaging: what is the duration of low risk after a normal scan?

OBJECTIVE: The goal of this study was to evaluate the very long-term outcome after normal exercise (99m)Tc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). Exercise (99m)Tc-sestamibi SPECT is widely used for risk stratification, but data on very long-term outcome after a normal test are scarce. METHODS: A consecutive group of 233 patients (122 men, mean age 54 ± 12 years) with known or suspected coronary artery disease (CAD) underwent exercise (99m)Tc-sestamibi SPECT and had normal myocardial perfusion at exercise and at rest. Follow-up endpoints were all-cause mortality, cardiac mortality, nonfatal myocardial infarction, and coronary revascularization. Predictors of outcome were identified by Cox proportional hazard regression models using clinical and exercise testing variables. RESULTS: During a mean follow-up of 15.5 ± 4.9 years, 41 (18%) patients died, of which 13 were cardiac deaths. A total of 18 (8%) patients had a nonfatal myocardial infarction, and 47 (20%) had coronary revascularization. The annualized event rates for all-cause mortality, cardiac mortality, cardiac mortality/nonfatal infarction, and major adverse cardiac events were, respectively, 1.1%, 0.3%, 0.7%, and 1.8%. Multivariate analysis demonstrated that the variables age, male gender, diabetes, diastolic blood pressure at rest, rate pressure product at rest, peak exercise heart rate, and ST segment changes were independent predictors of major adverse cardiac events. CONCLUSION: Patients with suspected or known CAD and normal exercise (99m)Tc-sestamibi myocardial perfusion SPECT have a favorable 15-year prognosis. Follow-up should be closer in patients with known CAD, and/or having clinical and exercise parameters indicating higher risk status.

Prediction of 9-year cardiovascular outcomes by myocardial perfusion imaging in patients with normal exercise electrocardiographic testing.

AIMS: Exercise myocardial perfusion imaging (MPI) is widely used, but the long-term prognostic value of this test in patients with normal exercise electrocardiographic testing is not defined. METHODS AND RESULTS: A consecutive group of 650 patients (428 men, mean age: 56 ± 11 years) with known or suspected coronary artery disease underwent exercise electrocardiographic testing and MPI. Follow-up endpoints were mortality and major adverse cardiac events (MACE). Predictors of outcome were identified by multivariate logistic regression analysis using clinical, exercise electrocardiographic testing and single-photon emission computed tomography (SPECT) variables. A total of 324 (50%) patients had an abnormal SPECT, and 131 (20%) had completely or partially reversible perfusion defects. During a mean follow-up of 9.2 ± 2.0 years, 107 (23%) patients died, 69 (11%) had a non-fatal myocardial infarction, 90 (14%) underwent coronary artery bypass surgery, and 142 (22%) percutaneous coronary intervention. Multivariate analysis demonstrated that the summed rest score was an independent predictor of mortality [hazard ratio (HR): 1.15, 95% confidence interval (CI): (1.08-1.22], P < 0.001). The summed stress score was an independent predictor of MACE [HR: 1.09, 95% CI: (1.04-1.13), P < 0.001]. The addition of SPECT variables to clinical and exercise electrocardiographic testing data provided incremental prognostic information for the prediction of mortality and MACE (both P < 0.001). CONCLUSION: Approximately 20% of patients with known or suspected coronary artery disease and normal exercise electrocardiographic testing have completely or partially reversible myocardial perfusion defects. MPI provides additional information for the prediction of 9-year cardiovascular outcomes in these patients.

Long-term prognostic value of dobutamine stress echocardiography in diabetic patients with limited exercise capability: a 13-year follow-up study.

OBJECTIVE: To determine the incremental prognostic value of dobutamine stress echocardiography (DSE) at 13-year follow-up (SD 3.2 years) for predicting mortality and cardiac events in diabetic patients. RESEARCH DESIGN AND METHODS: A total of 396 diabetic patients (mean age 61 ± 11 years; 252 men [64%]) with limited exercise capacity who underwent DSE for evaluation of ischemia were studied. End points were all causes of mortality, cardiac death, and hard cardiac events (cardiac death and nonfatal myocardial infarction). RESULTS: During a mean follow-up of 13 years, 230 patients (58%) died (121 cardiac deaths), and 30 patients had nonfatal myocardial infarction. Cumulative survival in patients with an abnormal DSE at 5, 10, and 15 years was 68, 49, and 41%, respectively. In patients with a normal DSE, these respective numbers were 74, 57, and 44%. Multivariate analyses showed that DSE provided incremental value over clinical characteristics and stress test parameters for prediction of mortality and cardiac events. Survival analysis showed that DSE provided optimal risk stratification up to 7 years after initial testing; after that period, the risk of adverse outcome increased comparably in both normal and abnormal DSE patients. CONCLUSIONS: DSE provided restricted predictive value of adverse outcome in patients with diabetes who were unable to perform an adequate exercise stress test. DSE provided optimal risk stratification up to 7 years after initial testing. Repeated DSE at that time might add to its prognostic value.