Storage age of transfused platelets and outcomes after cardiac surgery

Background: The relationship between duration of platelet (PLT) storage, currently limited to 5 days, and surgical outcomes has not been established. We tested the hypothesis that PLT storage age was associated with adverse outcomes. STUDY DESIGN AND METHODS: A retrospective cohort of aortocoronary bypass (CABG) surgery patients from January 1996 to January 2005 receiving one or more PLT transfusions was selected for study. The composite primary ("short- term") outcome was 30-day mortality or prolonged hospital stay. Secondary outcomes included complications and survival to annual follow-up. Multivariable logistic regression models and Cox proportional hazards regression analysis evaluated the association between PLT storage age and outcomes, expressed as an odds ratio (OR) or hazard ratio with 95% confidence intervals (CIs), respectively. RESULTS: PLT transfusion was administered to 3272 of 10,275 CABG patients and 2578 received units of known storage age, which ranged between 2 and 5 days (median, 4 days; 25th percentile, 3 days; 75th percentile, 5 days). The mortality rate for the 1637 patients receiving a single plateletpheresis transfusion was 3.8%, while 21.6% experienced a prolonged hospital stay or death. After adjusting for the number of PLT and red blood cell (RBC) units transfused, RBC storage age, and preoperative mortality risk, there was no association between PLT storage age and short-term outcome (OR, 1.01; 95% CI, 0.90-1.14), survival (hazard ratio [HR], 1.04; 95% CI, 0.96-1.13), or postoperative infections. CONCLUSIONS: PLT storage age was not associated with adverse short-term outcomes, decreased long-term survival, or infections after cardiac surgery.