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Liberal or restrictive transfusion after cardiac surgery
Gavin J Murphy1, Katie Pike, Chris A Rogers
1From the British Heart Foundation, Department of Cardiovascular Sciences, University of Leicester, and Glenfield General Hospital, Leicester (G.J.M.), Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol (K.P., C.A.R., G.D.A., B.C.R.), and Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford (S.W., E.A.S.) - all in the United Kingdom.
Insights
A restrictive red-cell transfusion threshold after cardiac surgery did not reduce postoperative morbidity or costs compared to a liberal threshold. The restrictive approach was associated with a higher mortality rate.
Area of Science:
- Cardiology
- Transfusion Medicine
- Critical Care Medicine
Background:
- The optimal hemoglobin threshold for red-cell transfusions post-cardiac surgery remains debated.
- Uncertainty exists regarding the comparative effectiveness of restrictive versus liberal transfusion strategies on patient outcomes and healthcare expenses.
Purpose of the Study:
- To compare the efficacy of restrictive versus liberal hemoglobin thresholds for red-cell transfusions in reducing postoperative morbidity and healthcare costs following cardiac surgery.
Main Methods:
- A multicenter, parallel-group trial involving over 2000 adult patients undergoing non-emergency cardiac surgery in the UK.
- Patients with postoperative hemoglobin <9 g/dL were randomized to restrictive (<7.5 g/dL) or liberal (<9 g/dL) transfusion thresholds.
- Primary outcome: serious infection or ischemic event within 3 months; secondary: healthcare costs.
Main Results:
- No significant difference in the primary composite outcome of serious infection or ischemic events between restrictive (35.1%) and liberal (33.0%) groups (OR, 1.11; 95% CI, 0.91-1.34).
- Higher mortality was observed in the restrictive group (4.2%) compared to the liberal group (2.6%) (HR, 1.64; 95% CI, 1.00-2.67; P=0.045).
- Total healthcare costs did not differ significantly between the two transfusion strategies.
Conclusions:
- A restrictive red-cell transfusion threshold is not superior to a liberal threshold in mitigating morbidity or healthcare costs after cardiac surgery.
- The findings suggest potential increased mortality with restrictive transfusion strategies in this patient population.
Background:
Whether a restrictive threshold for hemoglobin level in red-cell transfusions, as compared with a liberal threshold, reduces postoperative morbidity and health care costs after cardiac surgery is uncertain.
Methods:
We conducted a multicenter, parallel-group trial in which patients older than 16 years of age who were undergoing nonemergency cardiac surgery were recruited from 17 centers in the United Kingdom. Patients with a postoperative hemoglobin level of less than 9 g per deciliter were randomly assigned to a restrictive transfusion threshold (hemoglobin level <7.5 g per deciliter) or a liberal transfusion threshold (hemoglobin level <9 g per deciliter). The primary outcome was a serious infection (sepsis or wound infection) or an ischemic event (permanent stroke [confirmation on brain imaging and deficit in motor, sensory, or coordination functions], myocardial infarction, infarction of the gut, or acute kidney injury) within 3 months after randomization. Health care costs, excluding the index surgery, were estimated from the day of surgery to 3 months after surgery.
Results:
A total of 2007 patients underwent randomization; 4 participants withdrew, leaving 1000 in the restrictive-threshold group and 1003 in the liberal-threshold group. Transfusion rates after randomization were 53.4% and 92.2% in the two groups, respectively. The primary outcome occurred in 35.1% of the patients in the restrictive-threshold group and 33.0% of the patients in the liberal-threshold group (odds ratio, 1.11; 95% confidence interval [CI], 0.91 to 1.34; P=0.30); there was no indication of heterogeneity according to subgroup. There were more deaths in the restrictive-threshold group than in the liberal-threshold group (4.2% vs. 2.6%; hazard ratio, 1.64; 95% CI, 1.00 to 2.67; P=0.045). Serious postoperative complications, excluding primary-outcome events, occurred in 35.7% of participants in the restrictive-threshold group and 34.2% of participants in the liberal-threshold group. Total costs did not differ significantly between the groups.
Conclusions:
A restrictive transfusion threshold after cardiac surgery was not superior to a liberal threshold with respect to morbidity or health care costs. (Funded by the National Institute for Health Research Health Technology Assessment program; Current Controlled Trials number, ISRCTN70923932.).
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