Venous thromboembolism after nephrectomy: incidence, timing and associated risk factors from a national multi-institutional database.

PURPOSE: To evaluate the rate of venous thromboembolism (VTE) after nephrectomy with specific focus on event timing and location (before or after hospital discharge) in order to identify modifiable risk factors and establish benchmarks for preventive interventions.
METHODS: Using the ACS-NSQIP database, we identified patients undergoing nephrectomy from 2006 to 2012. Patients were analyzed in two cohorts: collectively and by surgical approach [open vs. lap/robotic (MIS)]. Rates of deep vein thrombosis (DVT) and pulmonary embolus (PE) were assessed and time to each event was established in relation to discharge status. Logistic regression analysis was performed to assess association between preoperative risk factors, surgical variables, and VTE.
RESULTS: In total, 13,208 patients met inclusion criteria. The overall rate of VTE was 1.2% (PE = 0.5% and DVT = 0.8, 0.1% DVT and PE). Using regression analysis, diabetes, dependent functional status, and longer operative time were associated with higher odds of DVT. For PE, dyspnea, disseminated cancer, and longer operative time were significant associations. The rate of VTE was higher in open surgery compared to MIS (2 vs. 0.8%, p < 0.001). Median times to DVT and PE were 8.5 and 6 days, respectively, with 53.3% of DVTs and 63.1% of PEs occurring prior to discharge.
CONCLUSIONS: The overall rate of VTE after nephrectomy is low, occurs roughly one week after surgery, and is associated with longer hospital stays. Certain patient factors, open surgical approach, and longer operative times were associated with higher odds of post-operative VTE; these patients may benefit from more aggressive prophylaxis.