Surgical Operative Time Increases the Risk of Deep Venous Thrombosis and Pulmonary Embolism in Robotic Prostatectomy

BACKGROUND AND OBJECTIVES: To evaluate the effect of operative time on the risk of symptomatic venous thromboembolic events (VTEs) in patients undergoing robot-assisted radical prostatectomy (RARP). METHODS: We reviewed the records of all patients at our institution who underwent RARP by a single surgeon from January 2007 until April 2011. Clinical and pathologic information and VTE incidence were recorded for each patient and analyzed by use of logistic regression to evaluate for association with VTE risk. All patients had mechanical prophylaxis, and beginning in February 2008, a single dose of unfractionated heparin, 5000 U, was administered before surgery. RESULTS: A total of 549 consecutive patients were identified, with a median follow-up period of 8 months. During the initial 30 days postoperatively, 10 patients (1.8%) had a VTE (deep venous thrombosis in 7 and pulmonary embolism in 3). The median operative time was 177 minutes (range, 121–360 minutes). An increase in operative time of 30 or 60 minutes was associated with 1.6 and 2.8 times increased VTE risks. A 5-point increase in body mass index and need for blood transfusion were also associated with increased risk of VTEs (odds ratios of 2.0 and 11.8, respectively). Heparin prophylaxis was not associated with a significant VTE risk reduction but also was not associated with a significant increase in estimated blood loss (P = .23) or transfusion rate (P = .37). CONCLUSION: A prolonged operative time increases the risk of symptomatic VTEs after RARP. Future studies are needed to evaluate the best VTE prophylactic approach in patients at risk.