Determinants of Radiation Exposure and Radiation Overexposure During Percutaneous Coronary Intervention. A Real-World Study of 10,634 Procedures With Development of a Pragmatic Radiation-Alert Risk Score

Background: Ionizing radiation is inherent to percutaneous coronary intervention (PCI) and may reach radiation-alert thresholds during complex procedures. Real-world data translating dose determinants into a usable planning-stage alert tool remain scarce. Aims: To determine the prevalence and predictors of radiation overexposure (RO) during PCI and to develop a pragmatic radiation-alert risk score usable before substantial dose accumulates. Methods: We analysed 10,634 consecutive PCI procedures performed between January 2008 and May 2018. Complex PCI was defined as unprotected left main, rotational atherectomy, chronic total occlusion (CTO), or bifurcation/trifurcation PCI. The composite RO endpoint was a dose-area product >500 Gy{middle dot}cm2, cumulative reference-point air kerma (AK) >5 Gy, or fluoroscopy time >60 minutes. A pragmatic score was built from early procedural variables. Results: Overall, 3,457 procedures (32.5%) were complex, and RO occurred in 99 (0.93%). Complex PCI showed higher RO rates than standard PCI (2.1% vs 0.4%; p<0.001). In multivariable analysis, body mass index (BMI), male sex, CTO, rotational atherectomy, bifurcation, and treatment of [&ge;]2 vessels independently predicted higher AK. A pragmatic score derived from early clinical and procedural variables showed good discrimination (area under the curve 0.772; 95% bootstrap CI 0.725-0.818) and was well calibrated (Brier score 0.0091; observed-to-expected ratio 0.994) for the composite RO endpoint. Conclusions: Radiation-alert thresholds were exceeded in approximately 1% of PCI procedures, but fivefold more often during complex PCI. A pragmatic, internally assessed score based on early procedural variables identified high-risk cases with good discrimination, supporting planning-stage risk stratification to activate dose-sparing strategies before substantial radiation has accumulated.