Impact of blood product transfusion on short and long-term survival after cardiac surgery: more evidence.

BACKGROUND

Despite the proven benefits in hemorrhagic shock, blood transfusions have been linked to increased morbidity and mortality. The short-term adverse effects of blood transfusion in cardiac surgical patients are well documented but there are very few studies that adequately assess the long-term survival. This study was undertaken to evaluate the effects of transfusion on both short-term and long-term survival after cardiac surgery.

METHODS

Data from 5,342 patients who underwent a cardiac surgical procedure from January 2002 to December 2005 at our institution were reviewed. The effect of transfusion of packed red blood cells (PRBC) and other blood products was tested in a 2-level approach of transfusion (any) versus no transfusion, and also a 4-level approach of transfusion (PRBC, other blood products, and both blood and blood products) versus no transfusion. Long-term survival data of these patients were obtained. Cox proportional hazard models, Kaplan-Meier survival plots, and hazard functions were used to compare the groups.

RESULTS

A total of 3,013 of the 5,342 study patients (56.4%) received transfusion during or within 72 hours of their cardiac surgery. Median time to death was significantly lower for patients who received transfusions; 1.15 years for PRC and 0.83 years for any transfusion, compared with 4.68 years in the non-transfused group. The overall 30-day mortality was 1.7%, but in patients who received transfusions (3.6%) was significantly higher than the non-transfused group (0.3%, p<0.001). The 1-year mortality (overall 3.9%) in the transfused group (7.3%, p<0.001) was also significantly higher than that in the non-transfused group (1.3%). The 5-year mortality rate in the transfused group was more than double that in the non-transfused group (16% vs 7%). After correction for comorbidities and other factors, transfusion was still associated with a 66% increase in mortality.

CONCLUSIONS

This study suggests that blood or blood product transfusion during or after cardiac surgery is associated with increased short-term and long-term mortality. It reinforces the need for prospective randomized controlled studies for evaluation of restrictive transfusion triggers and objective clinical indicators for transfusion in the cardiac surgical patient population.