Ximelagatran versus Warfarin To Prevent Blood Clots after Knee Replacement Surgery

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What is the problem and what is known about it so far?

Deep venous thrombosis (DVT), a condition in which blood clots form in leg veins and cause pain and swelling, is a common complication of knee replacement surgery. Pieces of these clots can break off and travel to the lungs, causing a serious and potentially deadly condition called pulmonary embolism. To prevent DVT, doctors prescribe blood thinners around the time of knee replacement surgery. Warfarin is a common blood thinner used for this purpose. Unfortunately, up to almost half of patients still develop DVT after knee replacement surgery even if they take warfarin. In addition, warfarin requires frequent blood tests and dose changes to make sure that patients are getting an appropriate amount of the drug. Ximelagatran is a newer blood thinner that has shown some promise in preventing DVT after hip and knee replacement surgery. An advantage of ximelagatran is that it does not require blood tests or dose changes.

Why did the researchers do this particular study?

To compare warfarin and ximelagatran in the prevention of DVT after knee replacement surgery.

Who was studied?

680 patients who had total knee replacement surgery at one of 74 North American hospitals.

How was the study done?

The researchers randomly assigned patients to get 1) ximelagatran twice a day beginning on the morning of the day of surgery or 2) warfarin once daily starting the evening of the day of surgery. They followed patients with tests to look for DVT, pulmonary embolism, and bleeding complications.

What did the researchers find?

Deep venous thrombosis occurred at similar rates in both groups. Bleeding complications were also similar in both groups.

What were the limitations of the study?

This study had limited ability to compare the side effects of ximelagatran and warfarin.

What are the implications of the study?

Ximelagatran seems to be a reasonable option for preventing DVT after knee replacement surgery.

Article and Author Information

  • The summary below is from the full report titled “Ximelagatran versus Warfarin for the Prevention of Venous Thromboembolism after Total Knee Arthroplasty. A Randomized, Double-Blind Trial.” It is in the 15 October 2002 issue of Annals of Internal Medicine (volume 137, pages 648-655). The authors are CW Francis, BL Davidson, SD Berkowitz, PA Lotke, JS Ginsberg, JR Lieberman, AK Webster, JP Whipple, GR Peters, and CW Colwell Jr.

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