Venous Thromboembolism (VTE) Rates Following the Implementation of Extended Duration Prophylaxis for Patients Undergoing Surgery for Gynecologic Malignancies

Abstract

The most common preventable cause of hospital death in the United States is venous thromboembolism (VTE). The risk of VTE among women undergoing major surgery for gynecologic cancer can be substantially reduced by use of postoperative VTE prophylaxis consisting of subcutaneous unfractionated heparin or low-molecular-weight heparin (LMWH) and mechanical prophylaxis. Evidence-based guidelines from several national organizations recommend that patients undergoing abdominal or pelvic surgery for malignancy receive this VTE prophylaxis regimen for up to 28 days postoperatively. Despite these recommendations, VTE prophylaxis is widely underused in this patient population. Poor compliance with the VTE prevention guidelines at the MD Anderson Cancer Center in Houston resulted in a higher than expected postoperative VTE rate among gynecologic-oncology patients. In 2009, standardized extended VTE prophylaxis practice guidelines were initiated at this institution for all patients undergoing laparotomy for gynecologic cancer to improve guideline compliance and reduce postoperative VTE rates. The aim of this study was to compare the incidence of VTE before and after the implementation of the standardized prophylaxis guidelines in women undergoing laparotomy for gynecologic cancer. Patients were started on LMWH within 24 hours of surgery, and it was continued for a total of 28 days postoperatively. The incidence of VTE diagnosed within 30 and 90 days of surgery in a postimplementation guideline group (extended-duration LMWH, n = 334) was compared with a preguideline historical group (no extended-duration LMWH, n = 300). The incidence of VTE diagnosed within 30 days of surgery was reduced by 78% in the postguideline group compared with the preguideline group (2.7% vs 0.6%, respectively; P = 0.040). However, the effect was not sustained when the preguideline and postguideline implementation groups were compared for VTE diagnosed within 90 days of surgery (3.7% vs 3.0%, respectively; P = 0.619). The median time between surgery and VTE diagnosis was significantly longer following implementation of the guidelines (57 vs 12 days, respectively; P = 0.012). These data show significant reduction of VTE rates in a cohort of women undergoing laparotomy for gynecologic malignancy who received extended-duration LMWH compared with similar patients who did not receive extended-duration LMWH. This effect was not sustained, however, when the groups were compared for VTE diagnosis within 90 days of surgery.