Changes in platelet function and coagulation after transcatheter aortic valve implantation evaluated with thromboelastography

Abstract

IntroductionThe possibility of hypercoagulability during the perioperative period of transcatheter aortic valve implantation (TAVI) has been noted; however, there is still a controversy regarding the appropriate perioperative antithrombotic therapy. The study investigated coagulation and platelet functions during the TAVI perioperative period using thromboelastography (TEG) 6s platelet mapping.MethodsA prospective observational study was conducted on 25 patients undergoing TAVI. TEG platelet mapping was performed at three time points: on admission to the operating room (before heparinisation), on postoperative day (POD) 1 and on POD 3. Perioperative changes observed included: maximum clot strength (MAHKH), clot strength without platelet function (MAActF), time to initiation of clots formation by coagulation factors (RHKH) and platelet function (Gp). Gpis activated by thrombin, and not affected by antiplatelet agents. It is calculated as [(5000×MAHKH)/(100 – MAHKH)] − [(5000×MAActF)/(100 – MAActF)]. Finally, MAADP/AAand GADP/AA, which reflect clot strength and platelet aggregation mediated by ADP/thromboxane A2receptors, respectively, were also examined using the same method as for Gp.ResultsMAHKHcontinued to decrease until POD 3, indicating antithrombotic change after TAVI. Gpcontinuously decreased for 3 days after TAVI, while MAActFincreased significantly on POD 3. Furthermore, RHKHshortened on POD 1 and POD 3, suggesting increased coagulation capacity after TAVI. Finally, GADPin clopidogrel-naive patients was reduced for 3 days after TAVI, while GAAin aspirin-naive patients showed no significant change perioperatively.ConclusionsIn this study involving TEG platelet mapping, coagulation capacity increased while platelet function decreased, resulting in antithrombotic change for 3 days after TAVI. The ADP receptor system may be implicated in the decreased platelet function. These results may be useful for considering optimal perioperative antithrombotic therapy in TAVI.