Practice patterns of ABO-matching for cryoprecipitate and patient outcomes after ABO-compatible versus incompatible cryoprecipitate.

BACKGROUND AND OBJECTIVES: This sub-study of the FIBRES trial sought to examine the patterns of ABO-compatible cryoprecipitate administration and to identify adverse consequences of ABO-incompatible cryoprecipitate. MATERIALS AND METHODS: This was a post hoc analysis of data collected from the FIBRES randomized clinical trial comparing fibrinogen concentrate with cryoprecipitate in the treatment of bleeding related to hypofibrinogenemia after cardiac surgery. The primary outcome was the percentage of administered cryoprecipitate that was ABO-compatible. Secondary outcomes were adverse events at 28 days. A follow-up survey was distributed to the FIBRES participating sites to examine the rationale behind the identified cryoprecipitate ABO-matching practice patterns. RESULTS: A total of 363 patients were included: 53 (15%) received ABO-incompatible cryoprecipitate and 310 (85%) received ABO-compatible cryoprecipitate. There was an increased incidence of post-operative anaemia in the ABO-incompatible group (15; 28.3%) in comparison to the ABO-compatible (44; 14.2%) group (p = 0.01) at 28 days, which was unrelated to haemolysis, without a significant difference in transfusion requirement. In the multivariable logistic regression models accounting for clustering by site, there was no observed statistically significant association between the administration of ABO-incompatible cryoprecipitate and any other adverse outcomes. Nine out of 11 sites did not have a policy requiring ABO-matched cryoprecipitate. CONCLUSION: This sub-study demonstrated that most cryoprecipitate administered in practice is ABO-compatible, despite the absence of guidelines or blood bank policies to support this practice. A signal towards increased risk of post-operative anaemia may be explained by higher rates of urgent surgery (vs. elective) in the ABO-incompatible group. Future studies should prospectively examine the impact of ABO-compatible versus incompatible cryoprecipitate to conclusively establish if there is a meaningful clinical impact associated with the administration of ABO-incompatible cryoprecipitate.