Structural Damage of Coronary Microcatheters During Chronic Total Occlusion Percutaneous Coronary Interventions: The Prospective Multicenter Cross Registry

BACKGROUND: Coronary microcatheters are essential in chronic total occlusion (CTO) percutaneous coronary intervention (PCI), but their structural failure has mainly been described through passive surveillance. AIMS: We aimed to determine the incidence, predictors, and procedural impact of microcatheter structural damage during contemporary CTO PCI. METHODS: The prospective multicentre CROSS registry included 2137 CTO PCI procedures performed at high-volume centers between 2024 and 2025. Suspected damaged microcatheters underwent centralized assessment and were classified as grade 1 (superficial deformation), grade 2 (significant deformation without complete fracture), or grade 3 (complete fracture). RESULTS: Structural damage occurred in 109 procedures (5.1%); 58.7%, 5.5%, and 35.8% were grade 1, 2, and 3, respectively. Independent predictors of structural microcatheter damage were moderate-to-severe calcification (adjusted OR, 1.93; 95% CI, 1.27-2.94), retrograde approach (adjusted OR, 1.71; 95% CI, 1.10-2.67), moderate-to-severe tortuosity (adjusted OR, 1.61; 95% CI, 1.04-2.50), and longer procedure duration (adjusted OR per 30-min increase, 1.17; 95% CI, 1.06-1.30). Structural damage was associated with increased periprocedural complications (25.7% vs. 7.7%; OR: 4.12, 95% CI: 2.60-6.52; p < 0.0001) and failed CTO PCI (11.0% vs. 3.1%; OR: 3.86, 95% CI: 2.01-7.39; p < 0.0001). CONCLUSIONS: Structural microcatheter damage occurred in approximately 1 in 20 CTO PCIs and was associated with anatomical complexity, demanding procedural circumstances, and substantially worse procedural outcomes.