Impact of Subtended Myocardial Mass Assessed by Coronary Computed Tomographic Angiography-Based Myocardial Segmentation.

Although decision-making for revascularization is based on the extent of ischemic myocardium, the prognostic implication of supplying myocardial territories has not yet been studied. To evaluate the clinical impact of the coronary artery-based myocardial segmentation (CAMS)-derived myocardial volume subtended to the poststenotic segment, and to determine clinically relevant coronary lesions, coronary computed tomography angiography, invasive coronary angiography, and preprocedure fractional flow reserve (FFR) data were analyzed in 664 deferred lesions (in 577 patients) and 401 treated lesions (in 369 patients) with drug-eluting stent implantation, respectively. Using CAMS method, the myocardial volume subtended to a stenotic coronary segment (V) was assessed. The primary composites included target vessel-related major adverse cardiac event (MACE) including cardiac death, myocardial infarction, and target vessel revascularization over 3 years. Independent predictors of 3-year MACE in deferred lesions were V (adjusted hazard ratio [HR] 1.02), FFR (adjusted HR per 0.1 = 0.60), and distal reference luminal diameter (adjusted HR 2.04, all p < 0.05). A V ≥ 36.2cc was predictive of MACE in deferred lesions with a sensitivity 72% and a specificity 67% (area under curve 0.71, 95% confidence interval 0.67 to 0.74, p < 0.001). V was not associated with target vessel-related MACE. For the prediction of FFR < 0.80, the area under curve of V/MLD > 6.3 was greater than those of angiographic diameter stenosis (0.78 vs 0.69) and minimal luminal diameter (0.78 vs 0.71), (all p < 0.05). CAMS-derived V predicted 3-year clinical outcomes in untreated coronary lesions, and improved the diagnostic performance of angiography-derived parameters to identify ischemia-producing lesions.