Platelet Transfusion in Cardiac Surgery: A Systematic Review and Meta-Analysis
Yanagawa B, Ribeiro R, Lee J, Mazer CD, Cheng D, Martin J, Verma S, Friedrich JO
Ann Thorac Surg. 2020
BACKGROUND Blood transfusion is a well-established independent risk factor for mortality in patients undergoing cardiac surgery but the impact of platelet transfusion is less clear. We performed a systematic review and meta-analysis of observational studies comparing outcomes of patients who received platelet transfusion following cardiac surgery. METHODS We searched MEDLINE and EMBASE databases to January 2019 for studies comparing peri-operative outcomes in patients undergoing cardiac surgery with and without platelet transfusion. RESULTS There were 9 observational studies reporting on 101,511 patients: 12% with and 88% without platelet transfusion. In unmatched/unadjusted studies, patients who received platelet transfusion were older with greater incidence of renal, peripheral and cerebrovascular disease, myocardial infarction, left ventricular dysfunction, and anemia. They were more likely to have non-elective, combined surgery; pre-operative hemodynamic instability and endocarditis; and more likely to be on clopidogrel preoperatively. Perioperative complications were significantly increased without adjusting for these baseline differences. After pooling only matched/adjusted data, differences were not found in patients who did vs did not receive platelets for operative mortality (risk ratio [RR] 1.26, 95%CI:0.69-2.32, p=0.46, 5 studies), stroke (RR 0.94, 95%CI:0.62-1.45, p=0.79, 5 studies), myocardial infarction (RR1.29, 95%CI:0.95-1.77, p=0.11, 3 studies), reoperation for bleeding (RR1.20, 95%CI:0.46-3.18, p=0.71, 3 studies), infection (RR1.02, 95%CI:0.86-1.20, p=0.85, 6 studies), and peri-operative dialysis (RR0.91, 95%CI:0.63-1.32, p=0.62, 3 studies). CONCLUSIONS After accounting for baseline differences, platelet transfusion was not linked with perioperative complications in cardiac surgery patients. Given the small number of observational studies, these findings should be considered hypothesis generating.
Transfusion triggers for guiding RBC transfusion for cardiovascular surgery: a systematic review and meta-analysis
Curley GF, Shehata N, Mazer CD, Hare GM, Friedrich JO
Critical Care Medicine. 2014;42((12):):2611–2624.
OBJECTIVE Restrictive red cell transfusion is recommended to minimize risk associated with exposure to allogeneic blood. However, perioperative anemia is an independent risk factor for adverse outcomes after cardiovascular surgery. The purpose of this systematic review and meta-analysis is to determine whether perioperative restrictive transfusion thresholds are associated with inferior clinical outcomes in randomized trials of cardiovascular surgery patients. DATA SOURCES The Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from inception to October 2013; reference lists of published guidelines, reviews, and associated articles, as well as conference proceedings. No language restrictions were applied. STUDY SELECTION We included controlled trials in which adult patients undergoing cardiac or vascular surgery were randomized to different transfusion thresholds, described as a hemoglobin or hematocrit level below which RBCs were transfused. DATA EXTRACTION Two authors independently extracted data from included trials. We pooled risk ratios of dichotomous outcomes and mean differences of continuous outcomes across trials using random-effects models. DATA SYNTHESIS Seven studies (enrolling 1,262 participants) met inclusion criteria with restrictive and liberal transfusion thresholds most commonly differing by a hemoglobin of 1 g/dL or hematocrit of 6-7%, resulting in decreased transfusions by 0.71 units of RBCs (95% CI, 0.31-1.09, p = 0.0002) without an associated change in adverse events: mortality (risk ratio, 1.12; 95% CI, 0.65-1.95; p = 0.60), myocardial infarction (risk ratio, 0.94; 95% CI, 0.30-2.99; p = 0.92), stroke (risk ratio, 1.15; 95% CI, 0.57-2.32; p = 0.70), acute renal failure (risk ratio, 0.98; 95% CI, 0.64-1.49; p = 0.91), infections (risk ratio, 1.23; 95% CI, 0.85-1.78; p = 0.27), or length of stay. There was no between-trial heterogeneity for any pooled analysis. Including four pediatric trials (456 participants) and 10 trials utilizing only intraoperative acute normovolemic hemodilution (872 participants) did not substantially change the results except that unlike the transfusion threshold trials, the hemodilution trials did not reduce the proportion of patients transfused (interaction p = 0.01). CONCLUSIONS Further randomized controlled trials are necessary to determine the optimal transfusion strategy for patients undergoing cardiovascular surgery.