Perioperative changes in coagulation and platelet contribution to clot strength after transcatheter aortic valve implantation: A study using thromboelastography and conventional markers

Introduction: Thrombotic and haemorrhagic complications have been reported following transcatheter aortic valve implantation (TAVI). However, few reports have studied perioperative changes in coagulation and platelet function after TAVI. Furthermore, there are no clear guidelines for antithrombotic therapy. This study aimed to examine the perioperative changes in coagulation and platelet contribution to clot strength after TAVI using thromboelastography (TEG 6s; Hemonetics). Methods: This prospective observational study included 15 patients scheduled to undergo TAVI for severe aortic stenosis. TEG 6s global haemostasis was used to record three measurements: on the day of surgery (immediately before the operation) and postoperative days 1 and 3. The reaction time R to thrombosis; K and alpha, which represent the rate of thrombosis; and the maximum amplitude (MA) were measured from the kaolin thromboelastography (TEG) curves. The coagulation index (CI) was calculated from the measurement results to assess thrombotic tendency. In addition, MA was converted to elastic clot strength, and platelet function was assessed by the difference, G(p), in elastic strength depending on platelet activation. Results: R and K decreased, and alpha tended to increase in kaolin TEG on days 1 and 3 after TAVI, indicating elevated coagulation function compared with the preoperative period, but MA and CI did not show significant changes. G(p) decreased significantly on days 1 and 3, suggesting a decrease in the platelet contribution to clot strength. Conclusions: Compared with the preoperative period, coagulation tended to increase, and platelet contribution to clot strength decreased from days 1 to 3 after TAVI.