Comparative Analysis of Patient Characteristics in Chronic Total Occlusion Revascularization Studies: Trials vs Real-World Registries

Background: The few randomized controlled trials (RCTs) on chronic total occlusion (CTO) percutaneous coronary intervention (PCI) are subject to selection bias. Objectives: The purpose of this study was to evaluate the differences between real-world CTO patients and those enrolled in RCTs. Methods: This study performed a meta-analysis of national and dedicated CTO PCI registries and compared patient characteristics and outcomes with those of RCTs that randomized patients to CTO PCI versus medical therapy. Given the large sample size differences between RCTs and registries, the study focused on the absolute numbers and their clinical significance. The study considered a 5% relative difference between groups to be potentially clinically relevant. Results: From 2012 to 2022, 6 RCTs compared CTO PCI versus medical therapy (n = 1,047) and were compared with 15 registries (5 national and 10 dedicated CTO PCI registries). Compared with registry patients, RCT patients had fewer comorbidities, including diabetes, hypertension, previous myocardial infarction, and prior coronary artery bypass graft surgery. RCT patients had shorter CTO length (29.6 ± 19.7 mm vs 32.6 ± 23.0 mm, a relative difference of 9.2%) and lower Japan–Chronic Total Occlusion Score scores (2.0 ± 1.1 vs 2.3 ± 1.2, a relative difference of 13%) compared with those enrolled in dedicated CTO registries. Procedural success was similar between RCTs (84.5%) and dedicated CTO registries (81.4%) but was lower in national registries (63.9%). Conclusions: There is a paucity of randomized data on CTO PCI outcomes (6 RCTs, n = 1,047). These patients have lower risk profiles and less complex CTOs than those in real-world registries. Current evidence from RCTs may not be representative of real-world patients and should be interpreted within its limitation.