Restricting Transfusions After Cardiac Surgery Shows No Benefit

Patients with a postoperative hemoglobin level of less than 9 g/dL were randomly assigned to a restrictive transfusion threshold (hemoglobin level lower 7.5 g/dL or a liberal transfusion threshold (hemoglobin level lower than 9 g/dL).

Primary outcomes were a serious infection (sepsis or wound infection) or an ischemic event within three months of randomization. Health care costs, excluding the index surgery, were estimated from the day of surgery to three months after surgery. The results showed that transfusion rates were 53.4% and 92.2% in the two groups, respectively. Primary outcome occurred in 35.1% of the patients in the restrictive-threshold group and 33% of the patients in the liberal-threshold group.

There were more deaths in the restrictive-threshold group (4.2%) than in the liberal-threshold group (2.6%). 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. The researchers also found that total costs did not differ significantly between the groups. The study was published on March 13, 2015, in the New England Journal of Medicine (NEJM).

“With an aging population and possibly an increase in heart disease, obesity and diabetes, it can only become more difficult in the future to maintain the national blood supply in the UK and in other developed countries around the world,” said corresponding author Barnaby Reeves, MD, of Bristol Royal Infirmary. “Our findings emphasize the importance of interventions to reduce blood loss in the first place.”

“Existing national and international transfusion guidelines recommend that blood transfusions only be given to patients who develop very low hemoglobin concentrations. We have shown that this strategy may increase the number of deaths in cardiac surgery,” said lead author, Professor of cardiac surgery Gavin Murphy, MD, of the University of Leicester.

In the United Kingdom, about half of all patients having cardiac surgery are given a RBC transfusion after the operation, depleting up to 10% of the nation’s blood bank. Since the patients who receive blood transfusions are also believed to have more complications (such as infections, heart attacks and strokes), researchers have speculated that a restrictive transfusion policy could improve clinical outcomes and help maintain an adequate blood supply.

Related Links:
University of Leicester
Bristol Royal Infirmary