PROGNOSTIC VALUE OF EXERCISE TL-201 IMAGING PERFORMED WITHIN 2 YEARS OF CORONARY-ARTERY BYPASS GRAFT-SURGERY

Objectives. We sought to determine the prognostic capabilities of exer cise thallium (TI)-201 tomographic imaging performed relatively early (within 2 years) after coronary artery bypass graft surgery (CABG). Ba ckground. Exercise testing is commonly performed after CABG, but few d ata exist demonstrating its prognostic value in this setting. Methods. Four hundred eleven patients were followed up for a median duration o f 5.8 years. Eleven prospectively chosen clinical, exercise and TI-201 variables were tested for their associations with outcome end points by means of proportional hazards regression models. Results. During fo llow-up there were 60 deaths from any cause, 53 initial cardiac deaths or nonfatal myocardial infarctions (MIs) and 22 late (>3 months after the TI-201 study) revascularization procedures. The number of abnorma l TI-201 segments on the postexercise image was the only variable in t he multivariate analyses to show a significant association with all th ree outcome end points: chi square 7.3, p = 0.007 for overall mortalit y; chi-square 8.1, p = 0.004 for cardiac death or MI; chi square 7.8, p = 0.005 for any cardiac event. Other independent predictors of outco me were exercise duration (chi-square 10.7, p = 0.001) and age (chi sq uare 3.9, p = 0.049) for overall mortality and exercise angina score ( chi-square 8.7, p = 0.003) for cardiac death or MI. The 5-year surviva l rate free of cardiac death or MI was 93% for patients without angina and a normal image or small postexercise perfusion defect versus 71% for patients with angina and a medium or large defect. Conclusions. Ex ercise TI-201 imaging performed within 2 years of CABG can stratify pa tients into low and high risk subgroups. (C) 1998 by the American Coll ege of Cardiology.