PROGNOSIS OF PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION, WITH AND WITHOUT VIABLE MYOCARDIUM AFTER MYOCARDIAL-INFARCTION - RELATIVE EFFICACYOF MEDICAL THERAPY AND REVASCULARIZATION

Background The uptake of F-18 deoxyglucose into dysfunctional segments after myocardial infarction identifies metabolically active (FDG+) or inactive (FDG-) myocardium. Although patients with FDG+ segments have been found to be at risk for adverse events, the prognostic significa nce of viable myocardium in relation to other influences on postinfarc tion prognosis, including revascularization, remain ill defined. The p urpose of this study was to investigate the relative prognostic signif icance of FDG+ tissue and to establish whether myocardial revasculariz ation in patients with viable tissue attenuates the risk of adverse ou tcome. Methods and Results One hundred thirty-seven patients with left ventricular dysfunction and resting perfusion defects after myocardia l infarction underwent positron emission tomography with both dipyrida mole stress Rb-82 perfusion imaging and FDG imaging. After the exclusi on of 4 patients proceeding to transplantation, 2 with uninterpretable scans and 2 lost to follow-up, 129 patients were followed clinically for 17+/-9 months. Four groups were defined: patients with FDG+ dysfun ctional myocardium who were revascularized (n=49) or treated medically (n=21) and those with FDG-segments who were revascularized (n=19) or treated medically (n=40). The groups of patients with FDG+ or FDG- fin dings, with and without revascularization, did not differ with respect to known determinants of postinfarction prognosis: age, left ventricu lar ejection fraction, or the prevalence of multivessel disease. Nonfa tal ischemic events occurred in 48% of medically treated FDG+ patients compared with 8% of revascularized patients with FDG+ tissue (P<.001) and 5% of patients with FDG- myocardium (P<.001). Thirteen patients d ied from cardiac causes; 11 (85%) had a left ventricular ejection frac tion of <30%, and these patients were evenly distributed between FDGand FDG- groups. Using Cox's proportional hazards model, only the pres ence of FDG+ myocardium (odds ratio, 12.9; P<.001) and the absence of revascularization (odds ratio, 5.8; P=.002) independently predicted is chemic events, while only age (P=.02) and ejection fraction (P<.001) b ut not the presence of viable myocardium were predictive of death. Con clusions Residual viable myocardium after myocardial infarction may ac t as an unstable substrate for further events unless it is revasculari zed. Despite this association, age and left ventricular dysfunction re mained the strongest predictors of cardiac death after myocardial infa rction in these patients with a spectrum of left ventricular dysfuncti on.