Liberal or Restrictive Transfusion After Cardiac Surgery | Journal Scan

Study Questions:

What are the benefits of a restrictive transfusion policy among patients undergoing cardiac surgery?


The authors conducted a multicenter, parallel-group trial in which patients undergoing nonemergency cardiac surgery who had a postoperative hemoglobin level of <9 g/dl were randomly assigned to a restrictive transfusion threshold (hemoglobin level <7.5 g/dl) or a liberal transfusion threshold (hemoglobin level <9 g/dl). The primary outcome was a serious infection (sepsis or wound infection) or an ischemic event (permanent stroke, 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.


The study randomized 1,000 patients to the restrictive arm and 1,003 to the liberal transfusion arm. Transfusion rates after randomization were 53.4% and 92.2% in the two groups, respectively. There was no difference in the primary outcome between the two arms (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, 0.91-1.34; p = 0.30). 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% confidence interval, 1.00-2.67; 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. There was no difference in total cost between the two groups.


The authors concluded that a restrictive transfusion threshold after cardiac surgery was not superior to a liberal threshold with respect to morbidity or health care costs.


Most observational studies have demonstrated worse outcomes in patients who receive transfusion after cardiac surgery, although the causal versus casual nature of this association has been extensively debated. This is the first large randomized controlled trial to test the value of a restrictive transfusion policy among patients undergoing cardiac surgery and demonstrates slightly worse outcome with a restrictive transfusion policy. Currently, most centers favor a restrictive transfusion policy, and this study is likely to cause re-examination of these policies. Data on transfusion threshold among patients with other cardiovascular disease are limited and similar studies are needed in patients with myocardial infarction or those undergoing invasive cardiac procedures.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention

Keywords: Cardiac Surgical Procedures, Blood Transfusion, Hemoglobins, Sepsis, Stroke, Acute Kidney Injury, Myocardial Infarction, Myocardial Ischemia, Postoperative Complications, Wound Infection, Health Care Costs, Random Allocation

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