The association between the transfusion of small volumes of leucocyte-depleted red blood cells and outcomes in patients undergoing open-heart valve surgery.

Objectives: The relationship between the transfusion of red blood cell (RBC) units and outcomes in patients undergoing cardiac surgery is the subject of intense debates. In this study, we investigated the relationship between the transfusion of 1-2 leucocyte-depleted (LD) RBC units and outcomes in patients undergoing open-heart valve surgery.

Methods: The investigation encompassed consecutive patients undergoing open-heart valve surgery at our institution between July 2009 and March 2015 who received no (RBC- group) or 1-2 units of LD RBC (RBC+ group). End-points were 30-day mortality (primary), the incidence of in-hospital major organ dysfunctions and 1-year mortality (secondary). Propensity score (PS)-adjusted statistical analysis was used to assess the effect of RBC transfusion on end-points.

Results: Thirty-day mortality rate was 0.2% (3/1485) in the RBC- group and 0.4% (6/1672) in the RBC+ group, with a PS-adjusted odds ratio (OR) for 30-day mortality of 1.00 (95% CI: 0.21-4.83;P = 0.99). The two groups showed no significant differences in PS-adjusted ORs for major complications, such as stroke, low cardiac output syndrome, thoracic wound infection and prolonged mechanical ventilation (>24 h). The PS-adjusted ORs for prolonged intensive care unit stay (>48 h) were, however, significantly higher in the RBC+ group (OR = 1.34 [95%CI: 1.04-1.72; P = 0.02]) than in the RBC- group. One-year mortality was comparable between groups (PS-adjusted hazard ratio for the RBC+ group: 0.85 [95% CI: 0.42-1.72; P = 0.65]).

Conclusions: Our data do not provide evidence that in patients undergoing valve surgery with cardiopulmonary bypass, transfusion of 1-2 units of LD RBC increases operative mortality, the incidence of postoperative complications or 1-year mortality.