Results of rotational thromboelastometry confirm venous thromboembolic risk prediction in urologic patients

Venous thromboembolic (VTE) complications contribute substantially to perioperative morbidity and mortality. The decision for mechanical and/or chemo-prophylaxis is currently based on VTE risk assessment models since conventional laboratory assays of coagulation usually fail to detect changes indicating hypercoagulability. Rotational thromboelastometry is a novel assay of coagulation, that it could potentially be used in objectively selecting patients at risk for VTE, who should indisputably undergo prophylaxis. We evaluated the association of conventional and novel assays of coagulation and VTE risk.

VTE risk was preoperatively assessed in 45 patients scheduled for endoscopic, open and laparoscopic urologic surgery, including transurethral resection of prostate, transurethral resection of bladder tumor, endoscopic vesical or ureteral stone lithotripsy, open prostatectomy, open cystectomy and urinary diversion, open or laparoscopic radical or partial nephrectomy, between March 2021 and October 2022, using three different risk assessment models (RAMs): the European Association of Urology (EAU) RAM, the American Urological Association (AUA) RAM, and the Caprini model. Patients under antiplatelet or anticoagulation agents were excluded. Patients' coagulation profile was determined by measuring PT, fibrinogen, aPTT, and rotational thromboelastometry analysis. For rotational thromboelastometry analysis, extrinsic rotational thromboelastometry and fibrinogen rotational thromboelastometry were examined in every patient. Statistical analysis was performed with ANOVA test and χ2 test.

Mean values of all rotational thromboelastometry variables did not vary significantly among different EAU VTE categories. In extrinsic rotational thromboelastometry assessment, a significant difference was observed in the mean values of the Clotting time (CT) between the different risk groups based on AUA RAM. In the comparison between the risk groups defined based on the Caprini score, statistically significant differences were observed in the extrinsic rotational thromboelastometry clot formation time (CFT). In fibrinogen rotational thromboelastometry analysis, significant differences were identified in the clot amplitude after five minutes (A5) and maximum clot firmness (MCF) indices between the AUA risk groups, along with a significant difference in the mean clot formation rate (CFR) value between the risk groups defined based on the Caprini score.

Rotational thromboelastometry can provide a detailed evaluation of the hemostatic status in patients undergoing urologic surgery that can be used as an adjunct to the VTE risk assessment models and thus, help to offer prophylaxis on a rather personalized basis. Future studies should assess the utility of thromboelastometry in identifying patients at high risk for VTE after major urological procedures.