Treatment of blood clots in the deep veins of the legs or the lungs with an older, less expensive form of the anticoagulant medication heparin can be just as safe and effective as similar treatment with a newer and more expensive heparin, according to a study led by Clive Kearon, professor of medicine at McMaster University, published in the August 23 issue of JAMA (The Journal of the American Medical Association).
When injected subcutaneously (beneath the skin), unfractionated (regular) heparin was shown in a randomized trial to work just as well as subcutaneous injection of the more expensive, low-molecular weight heparin in the treatment of venous thromboembolism. Traditionally, when unfractionated heparin is used in treatment, it is administered intravenously and accompanied by coagulation monitoring, which requires hospitalization. This standard approach includes ongoing dose adjustment in response to measurement of the APTT, a test that measures how fast the blood clots in a test tube under certain conditions.
The newer low-molecular weight heparins, which are administered by injection in fixed-weight doses, have gradually been replacing unfractionated heparin.
Kearon and colleagues conducted a randomized trial to study how fixed-dose, subcutaneous injection of unfractionated heparin compared to injection with the newer heparin in the treatment of blood clots in the legs or lungs.
The study was conducted from September 1998 through February 2004 at six university-affiliated clinical centres in Canada and New Zealand. Patients in the trial received either unfractionated or low-molecular-weight heparin administered subcutaneously every 12 hours. About 70 per cent of both groups were treated as outpatients. All patients received three months of warfarin (an anticoagulant drug) therapy.
Recurrent thromboembolism occurred in 3.8 per cent of the 345 patients in the unfractionated heparin group, and in 3.4 perce
Contact: Veronica McGuire