Temporal trends in retrograde crossing of epicardial collaterals in chronic total occlusion percutaneous coronary intervention

BACKGROUND Epicardial collaterals represent a conduit for retrograde crossing in chronic total occlusion (CTO) percutaneous coronary intervention (PCI), but carry higher procedural risk compared with septal or bypass graft crossing. METHODS We analyzed 1527 CTO PCI cases attempted via epicardial collaterals between January 2012 and March 2026 from the PROGRESS-CTO multicenter registry (49 centers). Temporal trends were assessed using logistic regression. Technical success, procedural success, and in-hospital major adverse cardiac events (MACE) were evaluated. RESULTS Mean patient age was 65 ± 10 years; 86.4% were men. Lesion complexity was high (mean J-CTO score 3.16 ± 1.02). Use of the retrograde approach overall and via epicardial collaterals decreased significantly over time (both p < 0.001). Epicardial collateral crossing success increased (p < 0.001), while MACE rates did not change significantly (p = 0.085). Technical and procedural success were 77.0% and 74.4%, respectively. In-hospital MACE occurred in 3.8% of cases. Coronary perforation occurred in 13.8% of procedures and was strongly associated with MACE (15.2% vs. 2.0%, p < 0.001). CONCLUSIONS In a large contemporary multicenter registry, while use of retrograde CTO PCI via epicardial collaterals declined over time, crossing success improved without a significant increase in complications, suggesting improved case selection and procedural expertise.