Additive value of thallium single-photon emission computed tomography myocardial imaging for prediction of perioperative events in clinically selected high cardiac risk patients having abdominal aortic surgery.

The present study was designed to prospectively evaluate whether reinjection thallium-201 single-photon emission computed tomography (SPECT) has a significant additive predictive value for occurrence of perioperative cardiac events in clinically selected patients at high cardiac risk undergoing abdominal aortic surgery. Of a group of 517 consecutive patients referred, 134 had > or = 2 of the following clinical or electrocardiographic cardiac risk variables: age > 70 years; history of myocardial infarction, angina, or congestive heart failure; diabetes mellitus; hypertension with severe left ventricular hypertrophy; and Q waves or ischemic ST-segment abnormalities on electrocardiogram at rest. Operation was performed after thallium SPECT study. Twelve patients (9%) had major perioperative events (cardiac death or nonfatal myocardial infarction) and 18 patients had other cardiac events (unstable angina, congestive heart failure, or severe ventricular tachyarrhythmia). Variables correlated with the occurrence of major events were history of myocardial infarction (p < 0.05) and the presence (p < 0.001) and number of segments with thallium reversible defects (p < 0.001). In multivariate analysis, history of myocardial infarction (p < 0.05) and the number of segments with reversible thallium defects (p < 0.001) were independent predictors. When all the cardiac events were taken into consideration, all the previous variables, as well as Q waves and ischemic ST abnormalities on the electrocardiogram, showed significant predictive value in both univariate and multivariate analyses. Furthermore, thallium SPECT imaging has an additive predictive value for major cardiac events over clinical and electrocardiographic risk factors. When performed on clinically selected patients at high cardiac risk undergoing abdominal aortic surgery, thallium SPECT demonstrates significant prognostic value for cardiac events over that provided by clinical variables alone.