Postoperative D-dimer predicts venous thromboembolism in patients undergoing urologic tumor surgery

We examined the incidence of pulmonary thromboembolism (PE) and deep venous thromboembolism (DVT) in patients who underwent urologic tumor surgery. The aim of this study was to investigate the postoperative D-dimer for prediction of venous thromboembolism events (VTE), as well as to identify other risk factors associated with the occurrence of thromboembolisms.

This was a prospective observational cohort study, which included 1,269 patients who underwent major urologic tumor surgery, from August 2015 to February 2017, at our center. Data comprising age, sex, body mass index, Charlson comorbidity index, type of surgery, Caprini score, postoperative D-dimer levels, and other laboratory tests were collected for analyses. Lower limb venous ultrasound was performed before surgery and the day before hospital discharge to measure DVT. Computerized tomography or ventilation/perfusion lung scan was applied to detect PE.

The overall incidence of VTE was 2.4% (31 cases) in 1,269 patients, consisting of 23 PE events and 9 DVT events. Patients undergoing radical cystectomy were most likely to suffer VTE (4.3%). The optimal cutoff value for postoperative D-dimer was 0.98μg/ml, according to the receiver operating characteristic curve analysis, with a sensitivity of 83.9%, and a specificity of 80.0%. On multivariate analysis, hypertension (odds ratio, OR = 2.5, 95% CI: 1.1-5.7; P = 0.026), Charlson comorbidity index ≥ 2 (OR = 5.6, 95% CI: 2.2-14.6; P<0.001), and D-dimer lever ≥ 1μg/ml on postoperative day 1 (OR = 12.52, 95% CI: 4.6-35.2; P<0.001) were independently associated with VTE after urologic tumor surgery.

The overall incidence of urologic-tumor-surgery-associated VTE in an Asian population is similar to those reported in European and North American series. Elevated D-dimer early after operation is an independent predictor of VTE in patients undergoing urologic tumor surgery. In addition, hypertension and the Charlson comorbidity index are both important clinical risk factors. The Caprini score recommended by the guideline is inadequate in this study population. The postoperative D-dimer plasma level is a more reliable marker for identifying patients at high-risk of developing venous thromboembolisms.