The MitraClip (Abbott Laboratories) is a percutaneous device for mitral valve (MV) repair, connecting the anterior and posterior leaflets of the mitral valve to eliminate mitral regurgitation (MR). Durability of MitraClip repair is an issue, with a 44% recurrence rate of grade 3 to 4 or higher MR within 2 years of clipping.1 Uneven MitraClip application is a common occurrence, with more posterior than anterior leaflet tissue grasped by the clip.2 To determine whether uneven clipping plays a role in MR recurrence, we investigated the effect of uneven clipping on leaflet stress, which is implicated in repair failure. Leaflets excised after failed MitraClip show significant tissue damage, including large perforations3; furthermore, in vitro studies have shown that increased leaflet stress alters collagen and proteoglycan synthesis, resulting in leaflet thickening and increased compliance.4,5 Leaflet stress after uneven clip application has not been previously studied. To determine whether uneven clipping contributes to increased stress and, therefore, to repair failure, we simulated a variety of MitraClip grasps, testing the hypothesis that uneven grasp does not increase leaflet stress.
Morgan AE, Wozniak CJ, Gulati S, Ge L, Grossi EA, Weinsaft JW, Ratcliffe MB. Association of Uneven MitraClip Application and Leaflet Stress in a Finite Element Model. JAMA Surg. Published online October 05, 2016. doi:10.1001/jamasurg.2016.3360