Role of fluorodeoxyglucose positron emission tomography scan in assessing the extent of myocardial viability in patients with left ventricular dysfunction and its impact on patient outcome

AIM: To assess the utility of fluorodeoxyglucose (FDG) PET-based myocardial viability in patients with left ventricular (LV) dysfunction, its role in guiding therapeutic decision-making, and its impact on patient outcomes. MATERIALS AND METHODS: This retro-prospective study included 70 patients of coronary artery disease, with myocardial infarction and LV dysfunction [left ventricular ejection fraction (LVEF) ≤ 35%]. All patients underwent rest single-photon emission computerized tomography myocardial perfusion imaging and FDG PET cardiac viability imaging. Viability was assessed qualitatively and quantitatively as the percentage of viable hibernating myocardium. Patients were categorized as having predominantly viable myocardium (≥7% viable hibernating LV myocardium) or predominantly scarred myocardium (<7%). Management decisions included surgical revascularization or medical therapy. Outcomes at 6-month followup included improvement in LVEF (≥5%), cardiac events, and cardiac-related death. RESULTS: During follow up, two patients died of noncardiac causes. Among 68 patients (mean LVEF 25.58%), 88.2% ( n = 60) had predominantly viable myocardium and 11.8% ( n = 8) had scarred myocardium on FDG PET cardiac scan. Of viable patients, 89.8% (44/49) undergoing revascularization showed LVEF improvement at least 5% vs. 45.5% (5/11) medically managed ( P = 0.002784). Cardiac events occurred in 4.1% vs. 27.3%, respectively ( P = 0.039). No significant association was found between treatment type and outcomes in the scarred group ( P = 0.464). CONCLUSION: FDG PET-based myocardial viability assessment can potentially play a role in guiding therapeutic decision-making in patients with LV dysfunction by identifying those with predominantly viable hibernating myocardium who are more likely to benefit from revascularization and have better outcomes in terms of improved LV function and fewer cardiac events compared to those managed medically.