Does Cardiopulmonary Bypass Influence Outcomes in Stage 2 Palliation? A meta-analysis and systematic review

The bidirectional Glenn (BDG) procedure, a key palliative intervention for single-ventricle physiology, is conventionally performed using cardiopulmonary bypass (CPB) despite its associated complications and costs. However, the comparative impact of CPB versus off-pump techniques on perioperative safety, neurological risk and long-term outcomes remains controversial. Therefore, this meta-analysis aimed to determine whether performing the BDG procedure without CPB improves perioperative outcomes (including morbidity, mortality, and neurological events), resource utilisation, and long-term survival compared to the conventional on-pump approach.

This review systematically searched PubMed, EMBASE and Cochrane Central from inception until January 2025 for comparative randomised and observational studies reporting outcomes in patients undergoing the BDG procedure with versus without CPB. The primary outcome was perioperative mortality (≤30 days or discharge); secondary outcomes included operative duration, recovery parameters (ventilation time, vasoactive support, intensive care unit (ICU)/hospital stay) and postoperative complications (infection, bleeding, neurological events, arrhythmias).

A total of 5 studies (2 randomised controlled trials, 3 observational studies; N = 339, 55% with CPB, 45% without CPB) were included. Patients had a mean age range of 6-66 months and mean weight of 6-16 kg. Common anomalies included double-outlet right ventricle and tricuspid atresia. Perioperative mortality did not differ significantly between groups (odds ratio [OR] = 1.15, 95% confidence interval [CI] = 0.31-4.20; P = 0.83). Significant benefits favouring the off-pump approach were observed for operation duration (mean difference [MD] = 31.98 min, 95% CI = 14.97-48.99; P = 0.0002), duration of inotropic support (MD = 7.05 hours, 95% CI = 5.48-8.63; P <0.00001), duration of mechanical ventilation (MD = 4.09 hours, 95% CI = 3.26-4.92; P <0.00001) and ICU length-of-stay (MD = 0.73 days, 95% CI = 0.55-0.91; P <0.00001). No significant differences were found for hospital length-of-stay, postoperative bleeding, neurological complications, oxygen saturation, superior vena cava pressure, infection or arrhythmias. Risk of bias was assessed via the ROBINS-I and ROB2 assessment tools for non-randomised and randomised trials, respectively; a funnel plot was constructed to assess for publication bias.

The findings suggest that, although off-pump BDG procedure is associated with shorter operative and recovery AU: Please provide the accepted date. times than the on-pump approach, it does not demonstrate superior perioperative mortality or hospital discharge outcomes. Given the risk of conversion and lack of extended follow-up in reporting studies, further randomised multicentre studies with standardised outcomes are warranted before off-pump is deemed a superior option.