Low-dose nicardipine during cardiopulmonary bypass improves carotid hemodynamics in CABG patients: a randomized controlled trial

Background Postoperative cognitive dysfunction (POCD) is a common complication of coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB), largely associated with cerebral hemodynamic disturbances. Carotid duplex ultrasonography–derived parameters, including peak systolic velocity (PSV-ICA) and end-diastolic velocity (EDV-ICA), provide reliable, noninvasive indicators of cerebral blood flow. This study evaluated whether intraoperative nicardipine infusion improves carotid blood flow and mitigates postoperative cognitive decline. Methods In this randomized, double-blind trial, 64 elderly patients undergoing CABG were assigned to receive either continuous low-dose nicardipine (0.2–0.5 µg/kg·min) during CPB (nicardipine group, n = 32) or saline (control group, n = 32). The co-primary endpoints were intraoperative PSV-ICA and EDV-ICA at four predefined time points (T1: pre-anesthesia; T2: surgery initiation; T3: during CPB; T4: post-CPB). Secondary endpoints included regional cerebral oxygen saturation (rScO₂), plasma neuron-specific enolase (NSE), Mini-Mental State Examination (MMSE) scores, vasopressor use, ventilation time, ICU stay, and hospitalization length. Results Baseline and intraoperative characteristics were comparable. Both groups showed reduced carotid flow velocities during CPB, but recovery of PSV-ICA at the end of CPB was significantly greater with nicardipine (63.7 ± 15.2 vs. 54.3 ± 13.9 cm/s; P = 0.025). EDV-ICA exhibited a similar trend without significant between-group differences. Secondary outcomes (MMSE, NSE) did not differ, and no adverse events occurred. Conclusion Continuous low-dose nicardipine during CPB significantly improved the recovery of PSV-ICA without affecting systemic hemodynamics or increasing adverse events. These findings suggest a potential intraoperative neuroprotective role of nicardipine, warranting confirmation in larger trials with long-term cognitive outcomes.