Absolute Resting13N-Ammonia PET Myocardial Blood Flow for Predicting Myocardial Viability and Recovery of Ventricular Function after Coronary Artery Bypass Grafting

Objective We aimed to evaluate the feasibility of resting myocardial blood flow (rMBF), quantified with dynamic 13 N-Ammonia (NH3) PET, for identifying myocardial viability and predicting improvement of left ventricular ejection fraction (LVEF) after coronary artery bypass grafting (CABG). Methods Ninety-three patients with coronary artery disease (CAD) and chronic LVEF < 45%, scheduled for CABG, had dynamic(13)NH(3)PET and(18)F-FDG PET imaging. The perfusion/metabolism polar maps were categorized in four patterns: normal (N), mismatch (M1), match (M2) and reverse mismatch (RM). The value of rMBF for identifying viable myocardium (M1, RM) and post CABG improvement of LVEF >= 8% was analyzed by receiver operating characteristic (ROC) curves. Correlations of rMBF in segments to Delta LVEF post CABG were verified. Results Mean rMBFs were significantly different (N=0.60 +/- 0.14; M1=0.44 +/- 0.07, M2=0.34 +/- 0.08, RM=0.53 +/- 0.09 ml/min/g,P<0.001). The optimal rMBF cutoff to identify viable myocardium was 0.42 ml/min/g (sensitivity=88.3%, specificity=82.0%) and 0.43 ml/min/g for predicting improvement of LVEF >= 8% (74.6%, 80.0%). The extent and rMBF of combined M1/RM demonstrated a moderate to high correlation to improved LVEF (r=0.78, 0.71,P<0.001). Conclusion Resting MBF, derived by dynamic(13)NH(3)PET, may be positioned as a supplement to(18)F-FDG PET imaging for assessing the presence of viable myocardium and predicting potential improvement of LVEF after CABG.

Automated summary

The study aimed to evaluate the feasibility of using dynamic 13N-Ammonia PET to quantify resting myocardial blood flow (rMBF) for identifying myocardial viability and predicting improvement of left ventricular ejection fraction (LVEF) after coronary artery bypass grafting (CABG). The results showed that rMBF can be used as a supplement to assess the presence of viable myocardium and predict potential improvement of LVEF after CABG.