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.

Transfusion of small amounts of leucocyte-depleted red blood cells and mortality in patients undergoing transapical transcatheter aortic valve replacement

There is an ongoing discussion about the impact of the transfusion of red blood cells (RBCs) on clinical outcomes in cardiac surgical patients. Compared with non-transfused patients, a recent retrospective analysis in patients undergoing transfemoral transcatheter aortic valve implantation (TAVI) indicates a dramatic increase in 30-day mortality in transfused patients, but no difference in 1-year mortality. We assessed the effect of the transfusion of 1-2 RBCs on early and late mortality in patients undergoing transapical (TA) TAVI. There were 430 patients who were not transfused (RBC-) and 209 patients who have received transfusions (RBC+). In the RBC- and RBC+ group, 30-day mortality rates were 2.8 and 1.4%, respectively. The propensity score-adjusted odds ratio of 30-day mortality was for the RBC+ group (reference: RBC- group) 0.44 (95% CI 0.11; 1.79; P = 0.252). One-year mortality rates were 12.1 and 17.6%, respectively. The propensity score-adjusted hazard ratio of 1-year mortality was higher in the RBC+ group than in the RBC- group (1.75 [95% CI 1.08;2.82]; P = 0.023). We conclude that in the group of very high-risk patients undergoing TA-TAVI, transfusion of 1-2 RBCs is not associated with an increased early mortality. However, adverse effects of transfusions on long-term survival cannot be definitely ruled out.