Reducing Heart Surgery Risks Using Less Blood

Aortic valve replacement patients may decrease complications with blood conservation strategies

(RxWiki News) One fifth of the US blood supply goes to heart operations. Because blood transfusions are costly and can lead to health complications, a blood conservation strategy may help.

As the US population ages, aortic valve disease is likely to grow. With this condition, the valve between the heart’s main pumping chamber (left ventricle) and the main artery (aorta) doesn't work properly. Even for the elderly, aortic valve replacement (AVR) is a standard treatment.

While surgeons use blood transfusions during AVR operations, a new study found that patients receiving two or more units of red blood cells were more likely to face major health problems compared to those who received less blood.

"Ask a doctor about blood conservation strategies during surgery."

David W. Yaffee, MD, and Eugene A. Grossi, MD, from the New York University Langone Medical Center in New York City, led research to evaluate the effect of a blood conservation strategy on patients undergoing AVR.

The strategy included minimizing the increase of fluid in the blood during surgery and not initiating transfusion until hemoglobin levels reached 8 grams per deciliter (g/dL) or less rather than 10 g/dL or less. Hemoglobin is the oxygen-carrying protein in red blood cells.

AVR patients are often given a blood transfusion to treat anemia — a lower than normal number of red blood cells. A transfusion is the process of intravenously introducing blood into a person’s circulation system.

Investigators reviewed data on 778 individuals who underwent AVR between 2007 and 2011. The mean age of patients was 72 with about a third aged 80 or older. The authors identified 391 patient who had AVR before blood conservation strategy was introduced and 387 who had AVR after such as strategy was implemented.

While there were no major differences between the two groups in terms of death rates or health complications, the researchers discovered that patients who received two or more units of red blood cells were more likely to experience kidney failure requiring dialysis, respiratory failure, sepsis (a toxic response to infection), gastrointestinal problems, and death. These patients were also more likely to have longer hospital stays.

Overall, the 387 patients who had AVR surgery after blood conservation strategy was started were 2.7 times less likely to receive red blood cell transfusions and 1.7 times less likely to have a major complications.

“While some patients do require transfusion for a safe operation, this study shows that we can limit transfusions without causing harm to the patient,” said Dr. Grossi in a press release.

The Society of Thoracic Surgeons (STS) and the Society of Cardiovascular Anesthesiologists (SCA) have already established clinical practice guidelines on blood conservation for coronary artery bypass grafting surgery.

Dr. Grossi said that these Blood Conservation Clinical Practice Guidelines could be “safely extended to patients undergoing aortic valve surgery.”

"For the past decade, researchers have been carefully examining the effects of blood transfusions. One might imagine that more blood is better, but this study and others show us that limiting exposure to blood transfusion is often in the patient's best interests," said Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas.

"While we certainly don't want the blood count to become dangerously low, most of us can safely recovery from mild or even moderate blood loss without the need for transfusion. It's also worth noting that blood transfusions require blood donors. In a matter of life-and-death, a little bit of blood can make all the difference," Dr. Samaan said.

The American Red Cross says that every two seconds someone in the US needs blood. Although an estimated 38 percent of the US population is eligible to donate, less than 10 percent do so each year. To find out more about donating blood, check the American Red Cross web site.

The study was published in the January 2014 issue of The Annals of Thoracic Surgery.

Review Date: 
January 4, 2014