Impact of Adherence to the Global Algorithm for Initial Crossing Strategy Selection in Chronic Total Occlusion Percutaneous Coronary Intervention

The global chronic total occlusion (CTO) crossing algorithm was developed by experts to improve CTO percutaneous coronary intervention (PCI) outcomes but has yet to be validated using real-world data. To evaluate the association between adherence to the global CTO crossing algorithm and outcomes in CTO PCI. We examined the clinical and angiographic characteristics and procedural outcomes of 13,852 CTO PCIs at 43 US and non-US centers between 2012 and 2025. Adherence to the global CTO crossing algorithm was defined using 3 characteristics: proximal cap ambiguity, poor distal vessel quality, and use of primary antegrade dissection/re-entry (ADR). Among 13,852 CTO PCIs, 70% (n = 9,693) followed the global CTO crossing algorithm. Discordant cases more frequently involved the right coronary artery (61.5% vs 49.4%, p < 0.001) and exhibited greater complexity: longer occlusions, proximal cap ambiguity, blunt/no stump, poor distal vessel quality, and calcification (all p < 0.001). Discordant lesions also had a higher J-CTO score (2.55 ± 1.18 vs 2.23 ± 1.27; p < 0.001). Algorithm adherence was associated with higher crossing success with the initially selected technique (72.5% vs 49.4%), technical (87.9% vs 85.6%), and procedural success (86.7% vs 84.2%) (all p < 0.001). The incidence of perforation was lower in concordant cases (4.1% vs 6.1%; p < 0.001), although major adverse cardiovascular events (MACE) were comparable. On multivariable analysis, algorithm adherence was independently associated with technical success (odds ratio 1.22; 95% confidence interval 1.04-1.42; p = 0.014). Adherence to the global CTO crossing algorithm is associated with greater crossing success using the initially selected strategy, higher technical success, and similar in-hospital MACE.