Some Cardiac Surgery Patients May Do Better With Female Donor Plasma for Transfusions

Kathryn Foxhall

February 18, 2010

February 18, 2010 — Cardiac surgery patients may do better if they receive plasma for transfusions from female donors rather than from male donors, according to a new study published online February 11 in the Journal of Thoracic and Cardiovascular Surgery.

In 2006, the AABB (formerly the American Association of Blood Banks) recommended that plasma for transfusions should come predominantly from male donors to reduce the incidence of transfusion-related acute lung injury (TRALI). The condition is estimated to cause about 200 deaths per year and is responsible for about half of all confirmed transfusion-related fatalities in recent years.

Studies have shown that the largest percentage of fatal TRALI cases are seen in people who received plasma from female donors with white blood cell antibodies, presumably developed during pregnancy.

Those AABB recommendations have been widely implemented by the blood banking community, and appear to have helped. The number of confirmed TRALI deaths decreased in 2008 to 35% of all confirmed transfusion deaths, according to the US Food and Drug Administration.

However, the current study looked at records from before the recommendations were implemented and found that cardiac surgery patients actually did much better, by some important measures, if they received plasma from female donors rather than from male donors.

Lower Rates of Death and Pulmonary Dyfunction With Female Donor Plasma

Looking at 390 pairs of patients, matched according to the number of units transfused and proximity of surgery dates, the researchers found that patients who received plasma from female donors had a pulmonary dysfunction incidence rate of 5.9% compared with 10.8% of those who received male donor plasma. In addition, the rate for patients who died or were hospitalized for longer than 10 days was 9% for those with plasma from female donors vs 16.4% for those with plasma from male donors.

Both groups did have similar long-term survival rates.

The study was not designed to look at TRALI itself, and the researchers say it can neither support nor refute the policy of excluding plasma from female donors for transfusions. However, they say the findings raise concerns that the policy "may have unanticipated effects on outcome in patients undergoing cardiac surgery and highlight a need for additional studies in this and other patient groups."

Twenty percent of plasma transfusions go to cardiac surgery patients, according to the authors.

One of the authors, Nicholas Bandarenko, MD, medical director of Duke Transfusion Services and associate professor of pathology, Duke University Medical Center, Durham, North Carolina, was quoted in a university news release as saying the blood banking community has been focused on reducing the significant harm from TRALI despite the fact that TRALI is a relatively rare event, happening in 1 of 3000 transfusions.

"This study suggests more subtle but still clinically significant outcomes and morbidity may be occurring," Dr. Bandarenko told Medscape General Surgery. "There appears to be a spectrum of pulmonary injuries that may be associated with blood transfusion, and these may not all be impacted by the policies that restrict plasma collection to male donors exclusively."

Policy Change Not Recommended Yet

Even so, Mark Stafford-Smith, MD, a professor of anesthesiology at Duke University and the senior author of the study, stressed they are not suggesting the policy should be changed at this point, even for cardiac surgery patients.

Among other things, he told Medscape General Surgery, the study points to an interesting tool to evaluate what happens with patients who get transfusions. A number of institutions around the country, he says, could take the same approach of linking blood bank data to records on patient outcomes and do this type of study for different kinds of patients in different settings.

Steven Kleinman, MD, chair of the AABB working group on TRALI that suggested the transfusion recommendations, says that although the Duke study appears to be well done, he agreed it is something that should suggest more research, but not change policy right now.

He pointed out that the study was retrospective, which increases the likelihood that unknown factors could affect the results. That raises the question, he acknowledges, as to whether a prospective study could ethically be done now, after the male-only plasma recommendations have been implemented.

An unanswered question is whether this study is "disruptive enough" to current thinking that researchers could ethically give a group of patients female donor plasma, with the assumed higher risk of TRALI, to compare their outcomes to patients receiving plasma from male donors, said Dr. Kleinman, who is also a professor at the University of British Columbia in Victoria, Canada.

Complicating that question, he says, are the current indications that the number of TRALI deaths has decreased since the male donor plasma policy was implemented and the fact the Duke study did not find a difference in mortality during about 4 years, after taking into account other health differences between the 2 groups.

Another TRALI expert, Ognjen Gajic, MD, associate professor at the Mayo Clinic College of Medicine in Rochester, Minnesota, says the AABB recommendations were based on previous prospective studies and a randomized controlled study, as well as increasing reports of transfusion-related deaths attributed to the plasma and platelets from "potentially alloimunized donors" (ie, women with multiple pregnancies).

A prospective study, supported by the National Institutes of Health and being done at University of California–San Francisco and the Mayo Clinic, will shed more light on TRALI mechanisms and the effects of the AABB policy changes, which came into effect halfway through the study.

The authors have disclosed no relevant conflicts of interest.

J Thorac Cardiovasc Surg. Published online February 11, 2010.

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