Prediction of side branch occlusions in percutaneous coronary interventions by coronary computed tomography: the CT bifurcation score as a novel tool for predicting intraprocedural side branch occlusion

Aims: Side branch (SB) occlusion is one of the major technical hurdles in the percutaneous coronary intervention (PCI) of bifurcation lesions. Our aim was to investigate whether preprocedural coronary computed tomography angiography (CCTA) could predict intraprocedural SB occlusion. Methods and results: A total of 260 bifurcation lesions were enrolled from 246 patients who underwent CCTA before elective bifurcation PCI. Quantitative plaque analysis was performed in the main vessel (MV) and SB. Intraprocedural SB occlusion occurred in 42 lesions (16%). These lesions were characterised by SB plaque, calcified plaque in the MV, low attenuation plaque in the main proximal segment or SB, and a ratio of MV to SB ostium area >4.3, which constituted a point-based CT bifurcation score. The CT bifurcation score was cross-validated, outperforming any angiographic Medina classification or RESOLVE score (c-statistics=0.749 versus 0.631 to 0.551; p<0.05 for all). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the CT bifurcation score ≥1 were 90%, 42%, 23%, 96%, and 50%, respectively. Conclusions: Comprehensive CCTA assessment was able to predict intraprocedural SB occlusion better than the current angiographic classification or scoring system. The CT bifurcation score may thus be a helpful guide for selecting the optimal bifurcation PCI strategy.