Objectives. To determine if quantification of the myocardial mass supplied by a side branch (SB) could be predictive of bifurcation percutaneous coronary intervention (PCI) outcomes. Methods. The authors examined the characteristics and outcomes of 73 patients (81 lesions) who underwent bifurcation PCI and had coronary computed tomography angiography (CCTA)-based computed flow-based calculation of myocardial mass at risk within 6 months prior. Results. The lesions analyzed were complex with high V-RESOLVE scores (12.0, 95%, interquartile range [IQR]: 9.0, 13.5). Provisional stenting was used in 67.9%, 2-stent techniques in 32.1%, and conversion from provisional to 2-stent stenting was performed in 11.1% of the lesions. The main vessel (MV) supplied 30.0% (IQR: 24.0%, 36.0%) and the SB supplied 10.0% (IQR: 7.0%, 13.0%) of the myocardium. Technical success was 94.9%. Major adverse cardiovascular events (MACE) occurred in 5.5% of the patients and SB occlusion (SBO) in 12.3% of the lesions. The ratio of SB to MV myocardial mass supply (SB/MV) was not associated with technical success (odds ratio [OR], 11.00; 95% confidence interval [CI], 0.01, 18.79; P = .500) or MACE (OR, 0.02; 95% CI, 0.00, 18.20; P = .300), but was associated with SBO (OR, 6.02*10-6; 95% CI, 2.42*10-10, 0.15; P = .020). SB/MV was normally distributed (W = 0.99, P = .467) with a mean of 0.35 (95% CI, 0.31, 0.38). In lesions where SBO occurred, V-RESOLVE scores were higher (16.0 vs 12.0, P = .017) and the SB/MV ratio was lower (0.22 vs 0.35, P = .007). Conclusions. Myocardial mass derived from CT analysis can help assess the risk of SBO after bifurcation PCI.
