Role of Thrombolestagrophy in Monitoring Perioperative Coagulation Status and Effect of Thromboprophylaxis in Bariatric Surgery

Thromboelastography is a technique that surveys the properties of viscoelastic blood clot. The purpose of this paper was to evaluate the hypercoagulability state and the effect of antithrombotic prophylaxis on thromboelastogram (TEG) results in bariatric surgery.

Twenty-five patients enrolled received 0.8 ml of nodraparin starting on the day before surgery and continuing postoperatively. TEG profile was collected before induction of anesthesia, on the first and third postoperative days. Each sample was run also in a cup added with heparinase to eliminate the interference of antithrombotic prophylaxis.

TEG analysis with heparinase showed a tendency to reduce the r-time (rate of initial fibrin formation) and k-time (time to clot firmness) and increase the alpha angle (rate of clot growth), while an increase of maximal amplitude (MA, a measure of maximal stiffness of the clot; p = 0.01) and GI or shear elastic modules strength (p = 0.03)was observed from basal to postoperative day 3 (POD3). TEG without heparinase evidenced and increase of r-time (p = 0.02) and k-time (p = 0.05), a reduction of the alpha angle (p = 0.03), and an increase of MA (p = 0.01) and GI (p = 0.03) from basal to POD3. The comparison of TEG techniques showed that normal TEGs had lower values of r-time and k-time and higher values of alpha angles and MA than TEG with heparinase. No differences were evident for basal and POD1 samples and the G values comparing the two TEG technique. No correlation was observed between the variation of normal TEG parameters and dosage of anticoagulant used in each patient.

Our patients presented a tendency to hypercoagulability determined most by MA and GI. Comparison between TEGs indicates that low-molecular-weight heparin not titrated on weight is able to determine a reduction of hypercoabulable tendency in the early postoperative period with few effects on increasing MA and GI.