External Validation of the UK‐BCIS CHIP Score to Predict 1‐Year Outcomes in Patients Undergoing IVL‐Assisted PCI: Insights From the International BENELUX‐IVL Registry

BACKGROUND: The United Kingdom-British Cardiovascular Intervention Society complex high-risk indicated percutaneous coronary intervention (UK-BCIS CHIP) score was developed to identify patient- and procedural factors to predict short-term adverse outcomes in patients undergoing high risk percutaneous coronary intervention (PCI). The performance of the UK-BCIS CHIP score in a patient population treated with intravascular lithotripsy (IVL) for severe coronary calcification remains unknown. AIMS: To evaluate the prognostic performance of the UK-BCIS CHIP score in patients undergoing IVL-assisted PCI for severe coronary calcification, and to assess procedural and 1-year clinical outcomes across CHIP score categories. METHODS: This international, multicenter, prospective study included consecutive patients undergoing IVL-assisted PCI between May 2019 and December 2025 from the BENELUX-IVL registry. Patients were stratified according to UK-BCIS CHIP score categories (0, 1-2, 3-4, and ≥ 5). The primary endpoint was 1-year major adverse cardiac events (MACE), defined as a composite of cardiovascular death, non-fatal myocardial infarction, or clinically driven target vessel revascularization. Secondary endpoints included all-cause mortality, procedural outcomes, and periprocedural complications. Discrimination of the UK-BCIS CHIP score was assessed using the AUC for in-hospital events and the Harrell's C-index for 1-year outcomes. RESULTS: A total of 911 patients were included. Higher UK-BCIS CHIP scores were associated with increased clinical comorbidity, lesion complexity, and procedural intensity. Procedural, device, and technical success rates were comparable across UK-BCIS CHIP score categories (85.1%, 94.4%, and 85.7% overall; p = 0.850, p = 0.813, and p = 0.781, respectively). Complications requiring intervention occurred in 5.5% of patients and did not differ significantly across CHIP score categories (p = 0.347). The 1-year cumulative incidence of MACE, accounting for all-cause death as a competing risk, did not differ significantly across UK-BCIS CHIP score categories (Gray's test p = 0.53). CONCLUSION: In IVL-assisted PCI, the UK-BCIS CHIP score effectively identifies patients with increased clinical and procedural complexity but shows limited discrimination for mid-term ischemic outcomes. IVL-assisted PCI is safe and effective across the full spectrum of CHIP risk, while long-term prognosis appears primarily driven by underlying comorbidity burden.