ROLE OF ADENOSINE TL-201 TOMOGRAPHY FOR DEFINING LONG-TERM RISK IN PATIENTS AFTER ACUTE MYOCARDIAL-INFARCTION

Objectives. This study prospectively evaluated whether early assessmen t with adenosine thallium-201 tomography could better refine risk stra tification on the basis of absolute extent of myocardial ischemia in p ostinfarction patients in clinically stable condition. Background. Pos tinfarction patients are at increased risk for subsequent cardiac even ts. However, identifying high risk patients among those with residual myocardial ischemia is suboptimal. Methods. All 146 patients enrolled underwent assessment of left ventricular function and had adenosine to mography performed early (mean [+/-SD] 5 +/- 3 days) after infarction. Excluded from analysis were 51 patients with revascularization after scintigraphy and 3 lost to follow-up. Statistical risk models were the refore generated from the remaining 92 patients. Results. Cardiac even ts occurred in 30 (33%) of 92 patients over 15.7 +/- 4.9 months. Univa riate predictors of all events were quantified perfusion defect size ( p < 0.0001), absolute extent of left ventricular ischemia (p < 0.00000 1) and ejection fraction (p < 0.0001), Risk was best predicted by Cox analysis on the basis of 1) absolute extent of ischemia and ejection f raction (chi square 24.6); 2) percent infarct zone ischemia and ejecti on fraction (chi square 24.4); or 3) total perfusion defect size and p ercent infarct zone ischemia (chi-square 18.9). The variables that pre dicted all cardiac events were equally powerful at predicting only dea th and nonfatal reinfarction. Death was best predicted by total perfus ion defect size. Conclusions. Risk analysis of individual patients ear ly after infarction is feasible on the basis of the quantified extent of scintigraphic ischemia and severity of left ventricular dysfunction .