Prediction of cardiovascular events in clinically selected high-risk NIDDM patients. Prognostic value of exercise stress test and thallium-201 single-photon emission computed tomography.

Abstract

We evaluated the prognostic value of an exercise stress test and thallium-201 scintigraphy for the prediction of cardiac events in selected high-risk NIDDM patients. NIDDM patients (n = 158, 105 men, aged 63 +/- 9 years) with two or more of the following criteria were prospectively included: age > or = 65 years, active smoking, hypertension > 160/95 mmHg, hypercholesterolemia (cholesterol > 5.70 mmol/l or LDL > 3.10 mmol/l), peripheral artery disease, abnormal rest electrocardiogram, or microalbuminuria (20-200 micrograms/min). An exercise-stress scintigraphy was performed in 77 patients able to exercise, while a dipyridamole scintigraphy was performed in 80 patients unable to exercise. Follow-up was 23 +/- 17 months. Major end points were cardiac deaths or nonfatal myocardial infarction. The annual event rate was 7.31% (deaths: 8, myocardial infarction: 14). Independent predictors of events were as follows: an age > 60 (P = 0.02), an abnormal rest electrocardiogram (P = 0.02), microalbuminuria (P = 0.001), the inability to exercise (P = 0.009), and the presence of more than two defects on scintigraphy (P = 0.001). A cardiac death occurred in 1.3% of patients able to exercise versus 8.8% of patients unable to exercise (odds ratio = 6.8, P = 0.001). Among patients unable to exercise, large perfusion defects corresponded to an annual mortality rate of 22.3%. Conversely, the negative predictive value of a normal scintigraphy for the occurrence of death was 97%. Inability to exercise and large perfusion defects on thallium-201 scan are major predictors of future death and myocardial infarction in high-risk NIDDM patients.