Angiographic Scoring System for Predicting Successful Percutaneous Coronary Intervention of In-Stent Chronic Total Occlusion

BACKGROUND No scoring models for IS-CTO have been established because of its in-stent characteristics.The purpose of this study was to develop a scoring model to predict the technical success of recanalizing in-stent chronic total occlusion (IS-CTO) by percutaneous coronary intervention (PCI).METHODS We retrospectively collected data from 474 patients who underwent an IS-CTO PCI from January 2015 to December 2018, consecutively.We selected clinical and angiographic factors and utilized a derivation and validation cohort (4:1 sampling ratio) analysis.Factors with strong correlations with technical failure, according