P1360MitraClip implantation as effective symptomatic therapy of dynamic mitral regurgitation unraveled by handgrip echocardiography

Abstract

Background: The dynamic nature of mitral regurgitation (MR) has become a recognized entity. Handgrip exercise may be an alternative approach to bicycle exercise especially in patients who are unfit to cycle. Percutaneous mitral valve repair using the MitraClip® (Abbott Vascular, Santa Clara, California) is a promising technique to treat symptomatic severe mitral regurgitation in patients at high or prohibitive surgical risk. There are currently no data which evaluated the benefit of MitraClip® in patients with exercise­induced increase in MR severity. Purpose: To investigate whether patients with symptomatic heart failure and exercise­induced changes in MR severity benefit from MitraClip®. Methods: We retrospectively included 306 patients who underwent MitraClip® implantation between 2011 and 2016 at our institution in an all­comers observational study. Our final patient group consisted of 92 patients who initially presented with moderate to severe MR thus receiving exercise echocardiography on top of comprehensive echocardiography examination at rest prior MitraClip® implantation. One­year outcome was monitored by follow­up examination or by telephone. The combined endpoint of the study was a composite of all­cause mortality and hospitalization for heart failure. Median follow­up period was 11 months. Results: Thirty­five patients (38%) had degenerative MR and 57 patients (62%) presented with functional MR. During handgrip exercise, regurgitation volume and effective regurgitation orifice area calculated by the PISA method increased from 34±14 ml at rest to 45±14 ml during exercise and from 21±10 mm2 to 25±9 2 mm , respectively (all p<0.01). According to current recommendations, 15 patients (43%) with moderate degenerative MR at rest and 25 patients (44%) with moderate functional MR at rest showed progression of MR severity during handgrip. There was no difference in post procedural MR severity between patients with marked exercise­induced changes in echocardiographic parameters and those without. During follow­up 36 patients (39%) experienced at least one event. By univariate and multivariate analysis, clinical outcome of patients with marked exercise­induced changes of MR severity was similar to those without (combined endpoint: no exercise induced increase in MR severity n=20 (35%) vs. exercise­induced increase in MR severity n=16 (46%), p=0.32). Conclusion: Handgrip exercise echocardiography serves as a valuable tool to unmask dynamic MR. Furthermore, these data provide first clinical evidence of the benefit of MitraClip® in patients with marked­ exercise induced increases in MR severity. These patients equally benefit from MitraClip® as patients without exercise­induced changes in MR severity do. The current data are relevant in the anticipation of large prospective trials investigating the clinical potential of percutaneous mitral valve repair therapy in intermediate MR at rest.