Abstract

BACKGROUND Perioperative red blood cell transfusion is associated with adverse outcomes after cardiac operations. Although restrictive transfusion protocols have been developed, their safety and efficacy are not well demonstrated, and considerable variation in transfusion practice persists. We report our experience with a restrictive transfusion protocol. METHODS We analyzed the outcomes in 409 patients undergoing cardiac operations enrolled in a trial conducted at 30 centers worldwide. Blood products were administered on the basis of a transfusion algorithm applied across all centers, with a restrictive transfusion trigger of hemoglobin less than or equal to 6 g/dL. Transfusion was acceptable but not mandatory for hemoglobin 6 to 8 g/dL. For hemoglobin 8 to 10 g/dL, transfusion was acceptable only with evidence for end-organ ischemia. RESULTS The patient population was moderately complex, with 20.5% having combined procedures and 29.6% having nonelective operations. The mean EuroSCORE for the population was 4.3, which predicted a substantial incidence of morbidity and mortality. Actual outcomes were excellent, with observed mortality of 0.49% and rates of cerebrovascular accident, myocardial infarction, and acute renal failure 1.2%, 6.1%, and 0.98%, respectively. The frequency of red blood cell transfusion was 33.7%, which varied significantly by center. Most transfusions (71.9%) were administered for hemoglobin 6 to 8 g/dL; 21.4% were administered for hemoglobin 8 to 10 g/dL with evidence for end-organ ischemia; 65.0% of patients avoided allogeneic transfusion altogether. CONCLUSIONS A restrictive transfusion protocol can be safely applied in the care of moderate-risk patients undergoing cardiac operations. This strategy has significant potential to reduce transfusion and resource utilization in these patients, standardize transfusion practices across institutions, and increase the safety of cardiac operations. Copyright 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Abstract

OBJECTIVES Cardiac surgery with cardiopulmonary bypass frequently leads to excessive bleeding, obligating blood product transfusions. Because low factor XIII (FXIII) levels have been associated with bleeding after cardiac surgery, we investigated whether administering recombinant FXIII after cardiopulmonary bypass would reduce transfusions. METHODS In this double-blinded, placebo-controlled, multicenter trial, 409 cardiac surgical patients at moderate risk for transfusion were randomized to receive an intravenous dose of recombinant FXIII, 17.5 IU/kg (n=143), 35 IU/kg (n=138), or placebo (n=128) after cardiopulmonary bypass. Transfusion guidelines were standardized. The primary efficacy outcome was avoidance of allogeneic blood products for 7 days postsurgery. Secondary outcomes included amount of blood products transfused and reoperation rate. Serious adverse events were measured for 7 weeks. RESULTS Study groups had comparable baseline characteristics and an approximately 40% decrease in FXIII levels after cardiopulmonary bypass. Thirty minutes postdose, FXIII levels were restored to higher than the lower 2.5th percentile of preoperative activity in 49% of the placebo group, and 85% and 95% of the 17.5- and 35-IU/kg recombinant FXIII groups, respectively (P<.05 for both treatments vs placebo). Transfusion avoidance rates were 64.8%, 64.3%, and 65.9% with placebo, 17.5 IU/kg, and 35 IU/kg recombinant FXIII (respective odds ratios against placebo, 1.05 [95% confidence interval, 0.61-1.80] and 0.99 [95% confidence interval, 0.57-1.72]). Groups had comparable adverse event rates. CONCLUSIONS Replenishment of FXIII levels after cardiopulmonary bypass had no effect on transfusion avoidance, transfusion requirements, or reoperation in moderate-risk cardiac surgery patients (ClinicalTrials.gov identifier: NCT00914589). Copyright 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Abstract

Bleeding following cardiac surgery involving cardiopulmonary bypass (CPB) remains a major concern. Coagulation factor XIII (FXIII) functions as a clot-stabilising factor by cross-linking fibrin. Low post-operative levels of FXIII correlate with increased post-operative blood loss. To evaluate preliminary safety and pharmacokinetics of recombinant FXIII (rFXIII-A(2)) in cardiac surgery, patients scheduled for coronary artery bypass grafting were randomised to receive a single dose of either rFXIII-A(2) (11. 9, 25, 35 or 50 IU/kg) or placebo in a 4:1 ratio. Study drug was given post-CPB within 10 to 20 minutes after first protamine dose. Patients were evaluated until day 7 or discharge, with a follow-up visit at weeks 5-7. The primary end-point was incidence and severity of adverse events. Thirty-five patients were randomised to rFXIII-A(2) and eight to placebo. Eighteen serious adverse events were reported. These were all complications well recognised during cardiac surgery. Although one patient required an implantable defibrillator, all recovered without sequelae. One myocardial infarction in a patient receiving 35 IU/kg rFXIII-A(2) was identified by the Data Monitoring Committee after reviewing ECGs and cardiac enzymes. No other thromboembolic events were seen. Dosing with 25-50 IU/kg rFXIII-A(2) restored levels of FXIII to pre-operative levels, with a tendency towards an overshoot in receiving 50 IU/kg. rFXIII-A(2), in doses from 11. 9 IU/kg up to 50 IU/kg, was well tolerated. For post-operative FXIII replenishment, 35 IU/kg of rFXIII-A(2) may be the most appropriate dose.