A recent study suggests blood transfusions may help explain women’s higher death rates following heart bypass surgery.
In this operation – known as coronary artery bypass grafting or CABG – surgeons improve blood flow to the heart by creating a detour around blocked arteries.
Mary Rogers and her coworkers at the University of Michigan Health System in Ann Arbor found that patients who received blood transfusions during CABG were 5.6 times more likely to die within 100 days following surgery than those who did not receive a transfusion, after accounting for other risk factors such as age and overall health. And women were more likely to receive blood transfusions than men: 88 per cent versus 67 per cent, respectively.
Further analysis showed that patients who received a blood transfusion were nearly three times more likely to get an infection than those who did not receive a transfusion. The findings are based on data from more than 9,200 patients who had CABG in Michigan during the late 1990s.
Dr. Keyvan Karkouti, an assistant professor at the University of Toronto and an anesthesiologist at the Toronto General Hospital, says the study addresses an important issue, but does not provide any final answers. “Whether or not it’s the blood transfusion itself that increases the risk, or … if it’s a marker for complications or sicker patients or harder surgery, I don’t think has been clarified yet.”
The Michigan researchers offer one theory to explain the association between transfusion and infection: White blood cells from donors may be infecting recipients with bacteria or viruses. However, both Canadian Blood Services and HÃ©ma-QuÃ©bec routinely filter out white blood cells from donated blood.