A Computational Fluid Dynamics-Based Risk Score Predicting 3-Year Cardiovascular Outcomes After Complex Left Main Bifurcation PCI: The SCORE-CLM.

Complex left main (LM) bifurcation lesions are among the most challenging forms of coronary artery disease, with suboptimal long-term outcomes after percutaneous coronary intervention (PCI), partly due to post-stenting hemodynamic disturbances not detected by conventional imaging. We developed and validated a CFD-based risk score predicting 3-year adverse cardiovascular (CV) outcomes after complex LM bifurcation PCI. In this observational cohort study, 211 patients undergoing successful drug-eluting stent implantation for LM bifurcation disease were included. Patient-specific 3D models were reconstructed using coronary angiography and intravascular ultrasound to perform transient CFD simulations. Five advanced shear-related metrics were extracted: low shear stress area (LSS), oscillatory shear index (OSI), endothelial shear stress angle deviation (ESSAD), helicity index, and mean wall shear stress (WSS). A composite CFD risk score (range 0-5) was created by assigning one point for each abnormal parameter. The primary endpoint was a composite of CV death, target lesion revascularization (TLR), and target vessel revascularization (TVR) at 3 years. Over 3 years, 11.3% of patients experienced the primary outcome. All CFD parameters significantly differed between event and non-event groups (p < 0.001). A Simulation-based Coronary Outcomes Risk Evaluation in Complex Left Main (SCORE-CLM) ≥ 3 showed strong predictive performance (sensitivity 81%; specificity 85%; negative predictive value 98%) and remained an independent predictor in multivariable analysis. These findings were confirmed in an internal validation cohort. The SCORE-CLM is a novel CFD-derived risk index that accurately predicts 3-year CV outcomes in patients undergoing PCI for complex LM bifurcation lesions.