Radiation burden in chronic total occlusion percutaneous coronary intervention is driven more by lesion complexity and planned strategy than by the target vessel

BACKGROUND: Radiation exposure is an important safety issue in chronic total occlusion percutaneous coronary intervention (CTO PCI). Right coronary artery (RCA) CTO PCI is often associated with a higher radiation burden, but it remains unclear whether this reflects the target-vessel location itself or differences in lesion complexity and strategy selection. METHODS AND RESULTS: We analyzed 1800 consecutive CTO PCI procedures performed between January 2020 and June 2025 at three participating CTO PCI centers (RCA n = 1013; left anterior descending coronary artery n = 540; left circumflex coronary artery n = 247). High radiation exposure was defined as a dose-area product (DAP) greater than the 90th percentile among available DAP values (>35 400 cGy·cm2). DAP was available in 1321 procedures (73.4%). RCA cases had longer fluoroscopy time and higher median DAP in unadjusted analyses. In the center-adjusted primary model, planned retrograde/hybrid strategy (adjusted odds ratio: 2.23, 95% confidence interval: 1.42-3.51) and higher J-CTO score (adjusted odds ratio: 1.70, 95% confidence interval: 1.39-2.09) were the strongest predictors of high DAP, whereas target vessel was not independently associated with excess radiation after adjustment. A Firth penalized center-adjusted sensitivity analysis yielded the same interpretation. Secondary analyses using continuous DAP and clinically relevant air kerma thresholds supported the same overall pattern. CONCLUSION: In CTO PCI, the higher radiation observed in RCA cases was mainly associated with lesion complexity and anticipated retrograde/hybrid strategy rather than with target-vessel location alone. These findings support strategy-based radiation risk assessment and careful donor-vessel protection when retrograde or hybrid crossing is expected.