Low-molecular-weight heparin (dalteparin) in women with gynecologic malignancy.

OBJECTIVE: To compare the efficacy of dalteparin, a low-molecular-weight heparin, to unfractionated heparin (UFH) in the prevention of deep venous thrombosis (DVT) and pulmonary embolism in patients after surgery for gynecologic malignancy.

METHODS: The medical records of all patients undergoing major surgery on the Gynecologic Oncology Service at the Massachusetts General Hospital from July 2002 through April 2003 were reviewed. Patients with confirmed malignancy were included. Between July 1, 2002, and November 15, 2002, dalteparin (5,000 U subcutaneously each day) was used for postoperative prophylaxis for DVT and pulmonary embolus. After November 15, 2002, the method of prophylaxis was changed to UFH (5,000 U subcutaneously every 8 hours) exclusively. Patients were evaluated for DVT or pulmonary embolus based on clinical suspicion using computed tomographic angiography, ventilation and perfusion scan, or lower extremity doppler.

RESULTS: A total of 214 patients were identified who met study criteria. Dalteparin was administered to 103 patients, and UFH was administered to 111. The rates of clinically significant DVT or pulmonary embolus in patients receiving dalteparin and UFH were 8.9% and 1.2%, respectively (P = .009). Major risk factors for DVT or pulmonary embolus, including age, obesity, duration of surgery, and type of malignancy, did not differ between groups. There were no significant differences in bleeding complications or transfusion requirements between groups.

CONCLUSION: The low-molecular-weight heparin dalteparin dosed 5,000 U daily is inadequate postoperative prophylaxis in women undergoing surgery for gynecologic cancer. In addition, heparin administered every 8 hours was not associated with increased bleeding complications. The use of dalteparin at the doses used in this study should be questioned until a large randomized trial shows efficacy in these high-risk patients.