OBJECTIVE This study was performed to define the incidence of acute deep venous thrombosis (DVT) after endovascular treatment of abdominal aortic aneurysms (AAAs). Because aortic endograft placement requires prolonged femoral vessel instrumentation, it may be hypothesized that these patients are at increased risk for development of an acute DVT. METHODS Fifty consecutive patients (42 men, eight women) ranging in age from 48 to 85 years (mean, 72 years) underwent endovascular treatment of an AAA from January 2000 to August 2001. Clinical examination and bilateral lower extremity duplex ultrasonography for DVT were performed on the first postoperative day and at the 1-month follow-up visit. No patient had a prior DVT or identifiable hypercoagulable state. Seven patients (14%) had concurrent malignant disease. Preoperative antiplatelet agents were administered in 26 patients (52%), and nine (18%) were on warfarin sodium therapy before surgery. No new DVT prophylaxis was initiated perioperatively. Epidural anesthesia was used in 60% of the patients, with general endotracheal anesthesia used in the remainder. Risk factors for DVT were evaluated with univariate statistical analysis. RESULTS Three patients (6%) had an acute postoperative DVT develop. Two occurred in the femoral veins, and one occurred in the popliteal vein. Of these patients, one had been continued on perioperative anticoagulation therapy, and the remaining two were started on low-molecular weight heparin and warfarin sodium therapy on recognition of the DVT. One patient had an intraoperative injury of the affected common femoral vein, and this individual was the only one to have clinical signs of a DVT. The mean follow-up period was 8 +/- 0.8 months. In this experience, factors that may have placed patients at increased risk for an acute DVT were not identified. CONCLUSIONS Six percent of patients undergoing endovascular repair of AAAs had postoperative DVT develop. These patients had a number of risk factors for the development of a DVT; however, no specific factor was identified that predisposed to DVT.