Mid-term analysis of randomized controlled clinical trial on different transfusion strategies for cardiac valve surgery

Objective: A study on whether restrictive transfusion strategy can reduce postoperative morbidity in cardiac valve surgery patients compared to liberal transfusion strategy.

Methods: This study employed a randomized, controlled, single-blind, parallel-group design, enrolling 439 patients undergoing non-emergency cardiac valve surgery with cardiopulmonary bypass. Patients were included if their hematocrit (Hct)≤24% or hemoglobin (Hb)≤80 g/L during cardiopulmonary bypass (CPB). Participants were randomized into a restrictive transfusion group (restrictive criteria: Hct≤18% or Hb≤60 g/L during CPB, and Hct≤21% or Hb≤70 g/L postoperatively) or a liberal transfusion group (liberal criteria: Hct≤24% or Hb≤80 g/L during CPB, and Hct≤30% or Hb≤100 g/L postoperatively). If Hb or Hct fell below the respective thresholds, 2 units of red blood cells were transfused, followed by re-evaluation. If levels remained below the threshold, an additional 2 units were transfused until the criteria were met. The primary outcome was a composite of postoperative 3-month mortality, infection, ischemic events, and new-onset renal failure requiring dialysis. Secondary outcomes included blood product utilization, hospital stay, costs and so on.

Results: The restrictive group included 221 patients and the liberal group included 218 patients. No statistically significant difference was observed in the primary outcome (restrictive group: 10.9% vs. Liberal group: 9.6%, P>0.05), 2 patints in restrictive group died and 3 patints in liberal group died. The transfusion rate was significantly lower in the restrictive group (19.0% vs. 100%, P<0.001), with no significant differences in other secondary outcomes (P>0.05). Subgroup analysis revealed an interaction between sex and transfusion strategy (P=0.023), suggesting that using liberal transfusion strategy in male patients might increase the risk of the primary outcome.

Conclusions: There's insufficient evidence to show that restrictive transfusion strategy reduces postoperative morbidity in cardiac valve surgery patients more effectively than liberal transfusion strategy.