Von Willebrand Factor Activity Association With Outcomes After Transcatheter Edge-to-Edge Mitral Valve Repair

Background: Residual mitral regurgitation (MR) is associated with worse outcomes after transcatheter edge-to-edge mitral valve repair (TEER). Shear stress induced by MR leads to altered von Willebrand factor activity (vWF:Act) and increased closure time with adenosine diphosphate (CT-ADP).

Objectives: The purpose of this study was to investigate the use of CT-ADP to monitor MR during TEER and the association between the vWF, residual MR, and clinical events post-TEER.

Methods: Sixty-five patients undergoing TEER were enrolled. CT-ADP was measured at baseline, after each clip deployment, 1 hour and 24 hours post-TEER. CT-ADP values were related to vWF:Act/vWF antigen (vWF:Ag) ratio at the same time points, and MR severity was assessed by echocardiography at 1 month. Combined events of all-cause mortality and heart failure hospitalizations were evaluated at 1 year.

Results: At 1 month, 32 (49%) patients had residual MR > mild (of those, 14% had MR > moderate). There was no significant change in CT-ADP values during the procedure. However, CT-ADP significantly decreased 1-hour post-TEER (P < 0.001). Patients with corrected MR demonstrated an increase in vWF:Act/vWF:Ag ratio 1-hour post-TEER. Elevated baseline vWF:Act/vWF:Ag ratio and the periprocedural percentage changes of the vWF:Act/vWF:Ag ratio (1 hour post-TEER - baseline values) were associated with the combined clinical outcome.

Conclusions: CT-ADP evolution in time was not quick enough to provide real-time monitoring of MR severity during TEER. However, vWF:Act/vWF:Ag ratio at baseline and its variations following the procedure were associated with clinical outcomes. Those findings will need external validation.