Fluorine 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Cardiac Viability Risk Stratification in Comparison with EuroSCORE II for Revascularization in Patients with Left Ventricular Dysfunction.

BACKGROUND: Diagnostic value of fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT) in the assessment of myocardial viable segments is well known; hence, it can identify patients with left ventricular (LV) systolic dysfunction who may benefit from revascularization. The presence of significant myocardial viable segments before revascularization will offer better prognosis with reduced mortality and morbidity. However, the usage of F18-FDG PET/CT myocardial viability study in the presurgical risk stratification is limited.

OBJECTIVE: The objective of the study is to predict perioperative mortality with hibernating viable myocardial (HVM) segments established by F18-FDG PET/CT in comparison with EuroSCORE II in patients with LV dysfunction undergoing coronary artery bypass grafting surgery.

MATERIALS AND METHODS: A prospective, observational study included 75 patients of chronic ischemic coronary artery disease with ejection fraction ≤40%. Tc-99m sesta-methoxyisobutylisonitrile myocardial perfusion single photon emission CT/CT and myocardial viability with F18-FDG PET/CT at rest were performed. Mortality risk stratification was done according to the EuroSCORE II. Patients were followed for post-coronary artery bypass graft surgery (CABG) 30-day mortality. Mortality observed by HVM segment groups were compared with EuroSCORE II predicted mortality.

RESULTS: Receiver operating curve for 30-day mortality prediction with HVM segments and EuroSCORE II was constructed. It showed that a cutoff of <4 HVM segments (area under the curve [AUC] = 0.7) had a sensitivity of 85%, whereas EuroSCORE II (AUC = 0.4) had only 28.6% sensitivity. EuroSCORE II underestimated perioperative risk in patients with <4 viable segments, that is 5 times higher risk was observed in patients with <4 viable segments.

CONCLUSIONS: HVM segments established by F18-FDG PET/CT had independently predicted mortality postoperatively. Hence, including F18-FDG PET/CT for viability assessment along with EuroSCORE II in preoperative risk assessment for revascularization by CABG in patients with LV dysfunction provided better risk stratification.