Impact of hibernating and viable myocardium on improvement in perfusion and left ventricular ejection fraction after coronary artery bypass graft

OBJECTIVES The association between the extent and degree of perfusion-metabolism mismatch and improvement in perfusion and left ventricular ejection fraction (LVEF) after revascularization was assessed. The secondary aim was to identify the best precoronary artery bypass graft surgery (pre-CABG) PET parameter, if any, to predict the improvement in the perfusion and LVEF after CABG. METHODS AND RESULTS Overal, 31 patients (mean age: 58+8.3 years) with ischemic left ventricle dysfunction underwent NH3 and F-FDG PET for the assessment of myocardial viability. CABG was performed in these patients and after a mean interval of 3 months, NH3 PET was repeated. The percentages of viable myocardium (VM), hibernating myocardium, degree of mismatch, and LVEF in pre-CABG PET were calculated. These were compared, the median [INCREMENT]LVEF and percent increase in perfusion being 5 (interquartile range: 3-9) and 78.7 (interquartile range: 51.3-100), respectively. No significant association was observed between the severity or extent of perfusion defect/mismatch and improvement in perfusion or LVEF after CABG. Patients with at least 65% VM predicted a 5-unit increase in LVEF at 88.9% sensitivity (P=0.1). CONCLUSION There was no significant relation between the severity and extent of perfusion-metabolism mismatch with improvement in perfusion and LVEF after CABG. After CABG for ischemic left ventricle dysfunction, VM shows a tendency toward better improvement in LVEF.