Anti-Bleeding Drug Not Risky During Heart Surgery

A new study published in the June issue of The Journal of Thoracic and Cardiovascular surgery suggests that use of aprotinin – a drug for reducing bleeding during heart surgery does not increase the risk of heart attack or stroke. The study findings contradict other recent studies that found the drug to be risky.

Led by Dr. C. Michael White, researchers at Hartford Hospital conducted the study in the wake of recent reports that suggesting patients who received aprotinin to reduce bleeding during heart bypass or valve replacement surgery had an increased risk of complications such as heart attacks, strokes, and kidney problems. The studies had prompted the FDA to issue an alert limiting the use of aprotinin during heart surgery.

While using a similar study method as the previous ones, the researchers limited their study to patients treated at Hartford Hospital. The reason for this was the different manner in which aprotinin is used at the hospital as compared to other hospitals.

“We thought our results might be different than what most hospitals had seen, because at Hartford Hospital, we reserved drug therapy to patients who would most benefit and we avoided a drug/laboratory test interaction that could have resulted in an increased risk of blood clots,” Dr. White said.

A total of 3,348 patients who underwent bypass or valve replacement surgery at Hartford Hospital between 2000 and 2005 were covered under the study. Analysis of the results revealed there was no increase in heart attack risk among patients receiving aprotinin. The risk of stroke was also found to be 35% lower, starkly in contrast with previous studies.

At the same time an increase was observed in the risk of kidney dysfunction after surgery, which was in support of earlier studies. There was however no indication of whether the kidney problems were permanent or temporary.

“Our study is important because it shows that if aprotinin is used selectively and a drug/lab test interaction is avoided, the drug does not hurt patients’ hearts or brains while reducing their need for blood transfusions and reoperations for bleeding,” said Dr. White.

The researchers believe one of the reasons behind their arriving at different findings is the limited use of aprotinin at Hartford Hospital; only patients undergoing particularly complex operations or those who refuse blood transfusions are administered the drug. Another major reason for conflicting results is that the doctors avoided a particular lab/drug test interaction that might cause inadequate anti-clotting treatment.

“During bypass or heart valve surgery, patients receive a drug called heparin to prevent blood clot formation,” Dr. White explained. “Surgery teams know how much to give because they measure the activated clotting time (ACT).”

“Previous studies have found that aprotinin makes the ACT rise erroneously if celite-ACTs are used. If you are using celite-ACTs to guide heparin dosing in a patient treated with aprotinin, you will think you gave enough heparin when in fact you didn’t,” he added. According to the researchers, this interaction might explain why previous studies found increased risks with aprotinin.

Despite the positive results of their study, Dr. White did not discount the importance of previous studies highlighting the risk from aprotinin. “Those studies were important, because they clearly showed that the way aprotinin was used around the world, by and large, was hurting patients more than helping them,” he said. “By using aprotinin selectively and avoiding the celite-ACT test, surgical teams can reduce the risk of bleeding problems during surgery without increasing the risks of heart attack or stroke.”

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