Preoperative Biomarkers and Thromboelastometry According to Caprini Venous Thromboembolism Risk Stratification in Bariatric Patients: Are Clinical Risk Assessments Enough?

Background: Obesity is associated with substantial thromboembolic risk; however, no standard laboratory method exists to stratify risk for postoperative thrombotic events. Our aim was to evaluate preoperative prothrombotic biomarkers and thromboelastometry in relationship to clinical venothromboembolism stratification in bariatric patients.

Study design: Preoperative blood samples were assessed for rotational thromboelastometry, D-dimer, C-reactive protein (CRP), plasminogen activator inhibitor-1, von Willebrand factor, and P-selectin, and compared with 50 normal control (NC) samples. Patients were stratified into Caprini Risk Score (CRS) groups: moderate (3 to 4), high (5 to 8), and very high (greater than 8) venothromboembolism risk.

Results: One hundred bariatric patients were assessed and risk stratified to CRS 3 to 4 (23), CRS 5 to 8 (67), and CRS greater than 8 (10). D-dimer, plasminogen activator inhibitor-1, and CRP were increased compared with NC, all p < 0.001, and P-selectin and von Willebrand factor demonstrated no differences compared with NC. D-dimer demonstrated significant differences between moderate, high, and very high-risk groups (all p < 0.05), and positive correlation with CRS ( r = 0.44, p < 0.001). On thromboelastometry, clot formation time (CFT) was faster than normal in 18% of patients, with maximum clot firmness higher than normal in 54% of patients. No difference was found comparing thromboelastometry between CRS groups. Significant correlations were found between CRP and CFT ( r = -0.44), α-angle ( r = 0.40), and maximum clot firmness ( r = 0.44), all p < 0.05, respectively. D-dimer negatively correlated with CFT ( r = -0.34, p < 0.05), and clotting time ( r = -0.78, p < 0.05) in very high-risk patients.

Conclusions: Preoperative D-dimer and CRP are significantly increased in bariatric patients and correlate with prothrombotic features on thromboelastometry. No significant differences were found comparing viscoelastic tests among CRS groups, which suggests patients with marked prothrombotic findings are not being differentiated into higher-risk categories by clinical assessment alone.