Women are more susceptible to blood loss and death during bypass surgery than men, researchers say

A team of researchers from Weill Cornell Medicine in New York City has come to the conclusion that women tend to be more vulnerable to blood loss during surgery—red blood cells, specifically—than men are.

They published their respective findings recently in the Journal of the American College of Cardiology.

Knowing that surgery-linked anemia raises risks for female patients should spur safeguards that can boost their survival during coronary artery bypass grafting (CABG) surgeries, the research team said.

The new study is based on data from over a million bypass patients, compiled by the Society of Thoracic Surgeons.

Those numbers confirmed the "sex gap": While 1.7% of men died during their bypass procedures, 2.8% of women did—a nearly 50% difference, the researchers noted.

They next looked at a wide range of possible factors that could drive this disparity. They included age, ethnicity, heart disease severity, history of prior heart attack, and the presence of other illnesses.

Only one factor stood out: Crunching the numbers, the aforementioned team of researchers found that 38% of the excess risk seen among female patients could be blamed on the impact of red blood cell loss during the surgery. It's a condition known as intraoperative anemia.

As the research team explained, some anemia is inevitable, because the heart-lung bypass machine that keeps patients alive during these surgeries relies on blood-diluting fluids.

However, women's average smaller body size, and the fact that they tend to arrive for bypass surgery with a lower red blood cell count than men, makes them more vulnerable to intraoperative anemia, the aforesaid team of researchers believes.

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