Optimization of hemocompatibility metrics in ventricular assist device design using machine learning and CFD-based response surface analysis

Ventricular assist devices (VADs) are essential for end-stage heart failure patients, but their design must balance hydraulic efficiency and hemocompatibility to minimize blood damage. This study presents a multi-objective optimization framework integrating computational fluid dynamics (CFD), Random Forest Regression (RFR), and Bayesian optimization to improve VAD rotor hemocompatibility. Seven key design parameters (inlet/outlet blade angles, blade count, rotational speed, clearance gap, blade thickness, and rotor length) were optimized using a D-optimal design of experiments. The RFR surrogate model demonstrated superior performance in handling the complex parameter interactions, achieving high predictive accuracy (R-2 > 0.84 for all hemocompatibility metrics). CFD simulations employing a Carreau-Yasuda blood model and rigorous mesh independence analysis evaluated shear stress distributions, exposure times, hemolysis index (HI), and platelet activation state (PAS). The optimized design achieved 97.24% of blood flow with shear stress <50 Pa, a HI of 0.01%, and PAS of 1 x 10(-6)%, representing significant improvements over baseline configurations. While this computational study provides comprehensive parametric insights, future experimental validation is recommended to confirm these findings under physiological conditions. The proposed framework offers a systematic approach for developing high-performance VADs with enhanced hemocompatibility.