Postoperative red blood cell transfusion and morbid outcome in uncomplicated cardiac surgery patients.

OBJECTIVE: To evaluate postoperative red blood cell (RBC) transfusion and its association with postoperative cardiac events and multiorgan morbidity in uncomplicated cardiac surgery patients. METHODS: A cohort of 945 patients from the 5,436 coronary artery bypass grafting patients enrolled in the international Multicenter Study of Perioperative Ischemia (McSPI) Epidemiology II (EPI II) study was investigated. Inclusion criteria were low to moderate risk profile, postoperative hemoglobin level ≥ 10 g/dl, minimal postoperative blood loss, and no evidence of any morbid event on the day of surgery. RBC transfusion was assessed during the first 24 postoperative hours and cardiac as well as multiorgan outcomes from postoperative day 2 to hospital discharge. Multivariate analysis was applied to assess the effect of RBC transfusion on multiorgan outcomes. A secondary propensity score analysis was performed in 4,465 patients without early postoperative morbid outcomes. RESULTS: Transfused patients (193/945, 20.4%) were more likely to suffer cardiac events (P = 0.03), harvest-site infection (P = 0.002), and composite morbidity outcome (P = 0.04). RBC transfusion was associated with cardiac events on multivariate as well as on propensity score analysis (adjusted odds ratio, 1.39; 95% confidence interval, 1.01-1.92; P = 0.04), and with harvest-site infection on multivariate analysis. Additionally, propensity score analysis suggested possible associations of RBC transfusion with increased risks for composite morbidity outcome and in-hospital mortality, renal morbidity, pneumonia, and mediastinitis. CONCLUSIONS: The data suggest a potential association between postoperative RBC transfusion and increased morbidity for cardiac surgery patients with low to moderate mortality risk profiles, adequate hemoglobin levels, and low bleeding rates.

The ongoing variability in blood transfusion practices in cardiac surgery.

BACKGROUND: Although blood utilization has been under considerable scrutiny for the past two decades, particularly for surgery, studies comparing perioperative blood transfusion practices between countries are rare, and the evolution of international standards remains unknown. Therefore, the objective of this evaluation was to compare the perioperative transfusion of blood components in cardiac surgery in multiple centers in different countries. STUDY DESIGN AND METHODS: Transfusion practice was investigated prospectively in 70 centers among 16 countries. A total of 5065 randomly selected cardiac surgery patients of the Multicenter Study of Perioperative Ischemia Epidemiology II (EPI II) Study were evaluated. Utilization of red blood cells (RBCs), fresh-frozen plasma (FFP), and platelets (PLTs) was assessed daily, before, during, and after surgery until hospital discharge. RESULTS: Intraoperative RBC transfusion varied from 9 to 100 percent among the 16 countries, and 25 to 87 percent postoperatively (percentage of transfused patients). Similarly, frequency of transfusion of FFP varied from 0 to 98 percent intraoperatively and 3 to 95 percent postoperatively, and PLT transfusion from 0 to 51 and 0 to 39 percent, respectively. Moreover, there were not only marked differences in transfusion rates between centers in different countries but also in interinstitutional comparison of multiple centers within countries. CONCLUSION: In cardiac surgical patients, marked variability in transfusion practice exists between centers in various countries and suggests differences in perioperative practice patterns as well as possible inappropriate use. International standardization of perioperative practice patterns as well as transfusion regimes appears necessary.

Impact of preoperative anemia on outcome in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: The risk of preoperative anemia in patients undergoing heart surgery has not been described precisely. Specifically, the impact of low hemoglobin per se or combined with other risk factors on postoperative outcome is unknown. Thus, we determined the effects of low preoperative hemoglobin and comorbidities on postoperative adverse outcomes in patients with coronary artery bypass graft in a large comprehensive multicenter study. METHODS AND RESULTS: The Multicenter Study of Perioperative Ischemia investigated 5065 patients with coronary artery bypass graft at 70 institutions worldwide, collecting approximately 7500 data points per patient. In 4804 patients who received no preoperative transfusions, we determined the association between lowest preoperative hemoglobin levels and in-hospital cardiac and noncardiac morbidity and mortality and the impact of concomitant risk factors, assessed by EuroSCORE, on this effect. In patients with EuroSCORE < 4 (n=2054), only noncardiac outcomes were increased, whereas patients with EuroSCORE > or = 4 (n=2750) showed an increased incidence of all postoperative events, starting at hemoglobin < 11 g/dL. Low preoperative hemoglobin was an independent predictor for noncardiac (renal > cerebral; P<0.001) outcomes, whereas the increase in cardiac events was due to other factors associated with preoperative anemia. CONCLUSIONS: Anemic patients undergoing cardiac surgery have an increased risk of postoperative adverse events. Importantly, the extent of preexisting comorbidities substantially affects perioperative anemia tolerance. Therefore, preoperative risk assessment and subsequent therapeutic strategies, such as blood transfusion, should take into account both the individual level of preoperative hemoglobin and the extent of concomitant risk factors.

Anemia and morbidity and mortality in coronary bypass surgery.

PURPOSE OF REVIEW: Anemia is associated with increased morbidity and mortality, in community-dwelling persons, in critically ill patients and perioperatively. The exact reasons and extent of the risks induced by anemia are not known, however, nor the optimal therapeutic approach. Based on the assumption that transfusion invariably counteracts the risks associated with perioperative anemia, most studies do not exclude the confounding effects of transfusion, and anemia is inconsistently defined. Cardiovascular disease was identified as a major additional risk for anemic patients, but the combined effects of decreasing hemoglobin and comorbidities in patients with coronary stenoses have not been determined exactly. This review integrates recent data to present a more differentiated understanding of mechanisms and risks of anemia in coronary artery bypass grafting surgery. RECENT FINDINGS: Patients with many comorbidities are more susceptible to the effects of anemia. Some outcomes may primarily be caused by concomitant risk factors associated with anemia rather than by low hemoglobin per se. The precise interactions of anemia and comorbidities to produce worse outcomes are still unclear, as is the optimal therapeutic approach. SUMMARY: The review highlights recent developments on anemia in heart surgery, and advocates new studies to institute individually adapted therapies.