Association between postoperative thromboembolism prophylaxis and complications following urological surgery

Thromboembolism represents the most significant complication and cause of non-surgical mortality in major urological surgery. The aim of the present study was to assess the association between the type of pharmacological thromboembolism prophylaxis and the postoperative complication rate in a cohort of patients undergoing major urological surgery. All consecutive patients treated with major urological surgery between December 2011 and March 2013 were evaluated. For each patient, clinical and demographic data, as well as information on the post-surgical complications and the type of pharmacological thromboembolism prophylaxis, were collected. In total, 453 patients (mean age, 63.36±12.05 years) were recruited (43.5% for prostate surgery, 33.1% for renal surgery, 12.1% for bladder surgery and 11.3% for other surgery). Postoperative blood transfusions were required in 50 cases (11.0%). A total of 32 patients (7.1%) underwent re-intervention due to the occurrence of grade ≥3 complications, with a readmission rate of 2.0%. According to the Clavien-Dindo Classification, the complications were grade 1 in 36.0% of the cases, grade 2 in 19.4%, grade 3 in 6.0%, grade 4 in 2.0% and grade 5 (mortality) in 0.7%. Only 1 case of deep venous thrombosis not associated with pulmonary thromboembolism was observed. Univariate analyses showed a significant negative association (higher risk of complications) between the use of >4,000 IU enoxaparin as the thromboembolism prophylaxis and postoperative blood transfusion rate (P=0.045), re-intervention rate (P=0.001) and the occurrence of grade ≥3 complications (P<0.001). Multivariate analysis confirmed the significant association between the use of >4,000 IU enoxaparin and both re-intervention rate (P=0.013) and occurrence of grade ≥3 complications (P=0.002). High doses of enoxaparin (>4,000 IU) may lead to an increased risk of re-intervention and severe postoperative complications following major urological surgery. Randomised, controlled trials comparing the effect of different types of pharmacological thromboembolism prophylaxis on postoperative complications following major urological surgery are required.