Background Transcatheter mitral valve repair is performed in a patient population at risk for thrombotic and bleeding events. The effects on platelet function and reactivity and their association with bleeding events after mitral transcatheter edge-to-edge therapy (M-TEER) have not been systematically examined.

Objectives We sought to investigate the association of different parameters of platelet function and thrombogenicity with bleeding events post M-TEER.

Methods In this single-center study, 100 consecutive patients with mitral regurgitation receiving TEER were analyzed. Blood was taken directly from the guide-catheter in the left atrium before and after placing the device. Blood samples were analyzed using impedance aggregometry (Multiplate) and TEG6s. The results were compared pre- and postprocedural. The primary outcome was any bleeding complication according to the Bleeding Academic Research Consortium classification within 6 months.

Results A total of 41 patients experienced bleeding events. TEG analysis showed a significant decrease in ADP aggregation and increase in ADP inhibition. In ROC-analysis, TEG ADP aggregation and inhibition and Multiplate ADP aggregation showed moderate predictive values for bleeding events. The delta-ADP-Test (Multiplate) showed the strongest prediction of bleeding (area under the curve: 0.69). Adding platelet function and TEG markers to a model of clinical bleeding risk factors improved the prediction for bleeding events.

Conclusion This study indicates that thrombogenicity might be affected immediately after M-TEER probably due to changes in flow conditions. In particular, platelet aggregation involving the ADP receptor pathway significantly correlated with postprocedural bleeding events. Whether these results could guide peri-interventional antithrombotic therapy and improve peri- and postprocedural outcome requires further investigation.