New Angiographic Difficulty Score for First-Attempt Chronic Total Occlusion in the 3 Major Coronary Arteries

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is still challenging due to complex lesion morphology. Success rates may vary among the 3 major coronary arteries, influenced by clinical and angiographic characteristics. This study sought to evaluate the differences in the predictors of unsuccessful PCI in first-attempt CTO lesions of the 3 major coronary arteries compared with the J-CTO (Japanese CTO) score. This study assessed 6,408 first-attempt CTO patients from the Japanese CTO-PCI expert registry between January 2014 and December 2021, randomly assigned to derivation and validation sets. Difficulty scores for each artery were determined by assigning points to predictive unsuccessful factors. The CTO lesions were distributed as follows: left anterior descending coronary artery: 2,245 (35%), left circumflex coronary artery: 1,131 (18%), and right coronary artery (RCA): 3,032 (47%). Regarding success rates, left circumflex coronary artery CTO had the lowest procedural success rate (90%) followed by RCA CTO (92%) and left anterior descending coronary artery CTO (94%). RCA CTO was significantly longer and more severely angulated, requiring more often the retrograde approach. A multivariate logistic analysis revealed that predictors of failed PCI were different in CTO lesions among the 3 major coronary arteries, respectively. Moreover, our difficulty score for RCA CTO was superior to the J-CTO score in predicting unsuccessful PCI. Clinical and angiographic differences might explain the discrepancies of success rates in CTO lesions among the 3 major coronary arteries. Our novel difficulty score was comparable to the J-CTO score in predicting unsuccessful CTO-PCI with a superior discriminatory capacity.