January 17, 2012
COLUMBUS, Ohio – People who need cardiac surgery, but are taking medications to prevent blood clots, may benefit from a new treatment that has proven to reduce risk for bleeding or other complications before, during and after surgery.
Researchers at Ohio State University Medical Center and other scientists examined the use of an investigative intravenous antiplatelet drug, cangrelor, and found it to be an effective bridge between long-lasting oral antiplatelet medications and cardiac surgery. The drug’s platelet inhibition rapidly loses effect within a few hours, so it can be discontinued just prior to surgery.
Results of the study are available online and in the January 18 edition of the Journal of the American Medical Association.
Dr. Michael Firstenberg, a co-author of the study and a cardiothoracic surgeon at Ohio State’s Medical Center, says antiplatelet medication is a cornerstone therapy for preventing clots in people with cardiovascular and peripheral vascular diseases or a history of previous stroke.
However, he says problems can arise when those people need surgery. Antiplatelet medications like aspirin, clopidogrel and prasugrel prevent the body’s platelets from working properly and limit the ability to form clots, which can cause strokes and heart attacks. Following current guidelines, most surgeons ask patients to stop taking antiplatelet drugs approximately five days before surgery, to allow platelet function to return to normal and to minimize concerns for excessive bleeding.
“Stopping antiplatelet therapy several days prior to surgery increases a patient’s short-term risk for complications like a blood clot, heart attack or stroke to about 12 percent. The exact risks are unknown and vary considerably from patient to patient, says Firstenberg. “Conversely, operating on a patient who is on antiplatelet medication increases the risk for transfusions and bleeding complications. This is a substantial medical management issue for surgeons.”
In the study, 210 patients at 34 international medical centers including Ohio State were randomized to stop oral antiplatelet therapy and receive either intravenous cangrelor or placebo for up to five days prior to coronary artery bypass surgery. Treatment stopped approximately three hours before incision. Researchers found patients treated with cangrelor maintained a low risk of clotting complications from platelet deactivation without a significant excess in bleeding or bleeding complications, compared to those on placebo.
“We are pleased with the findings. We think this is a safe and effective method and it has potential for changing the model of how we handle patients in the preoperative and postoperative periods,” says Firstenberg. “This not only has implications for cardiac surgeries, but many other surgeries as well. Anyone taking an antiplatelet agent because of a coronary stent or previous heart attack or stroke and who needs surgery might benefit from this drug.”
Additional results from this study will be presented at the American Association for Thoracic Surgery annual meeting in May 2012.
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