Cardiopulmonary bypass (CPB) priming may influence haemodilution, bleeding, and end-organ injury during HeartMate 3 (HM3) implantation, but evidence in contemporary left ventricular assist device (LVAD) surgery is limited.

We retrospectively analysed 92 HM3 implantations (2015-2025) by priming strategy (blood-based [FFP + RBC], n = 36; crystalloid, n = 56). The primary end-point was postoperative right heart failure (RHF; Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS]). Multivariable regression and propensity score-based inverse probability of treatment weighting (IPTW) sensitivity analyses were performed.

Baseline characteristics were balanced between groups, with comparable age (blood-based: 58 [49.5-66.0]; crystalloid: 62 [55.8-68.2]; P = .069) and female sex (blood-based: n = 3/36 [8.3%]; crystalloid: n = 8/56 [14.3%]; P = .518). Right heart failure was lower with blood-based priming (blood-based: n = 3/36 [8.3%]; crystalloid: n = 17/56 [30.4%]; P = .012; adjusted OR 0.23 [95% confidence interval (CI) 0.06-0.86]; P = .030). Dialysis was lower unadjusted (blood-based: n = 4/36 [11.1%]; crystalloid: n = 18/56 [32.1%]; P = .021), with a directionally lower adjusted estimate (OR 0.30 [95% CI, 0.09-1.01]; P = .053). Delirium was lower with blood-based priming (blood-based: n = 3/36 [8.3%]; crystalloid: n = 16/56 [28.6%]; P = .019; adjusted OR 0.22 [95% CI, 0.06-0.84]; P = .027). Survival did not differ significantly (log-rank P = .055; adjusted HR 0.59 [95% CI, 0.27-1.32]; P = .201). IPTW analyses showed lower delirium (OR 0.23 [95% CI, 0.06-0.84]) and an attenuated RHF association (OR 0.35 [95% CI, 0.10-1.23]).

Blood-based CPB priming was associated with lower RHF and delirium, and directionally lower dialysis rates, after HM3 implantation. Survival estimates were not statistically significant. Findings require prospective validation.