Using the RCS curves, we further identified thresholds where the odds ratio exceeded 1: ischemic stroke risk significantly increased when cardiopulmonary bypass time exceeded 255.1 min, intraoperative blood loss surpassed 2442.2 ml, operation time exceeded 8.3 h, intraoperative plasma transfusion volume exceeded 434.1 ml, myoglobin levels exceeded 140.3 ng/mL, and age was above 52 years. The gene discussed is MB; the disease is ischemic stroke.