P5571MitraClip implantation impairs functional echocardiographic parameters of the left atrium in patients with moderate to severe mitral regurgitation

Abstract

Abstract Background MitraClip implantation induces hemodynamic unloading and reverse remodeling of the left atrium (LA) and the left ventricle (LV). However little data exist concerning the effects of MitraClip implantation on LA and LV strain reflecting LA and LV function. Methods and results From August 2017 to September 2018 62 patients with moderate to severe mitral regurgitation were prospectively enrolled in our single-center RETORT-MR trial (Regensburg Trial on TMVR Techniques in Mitral Regurgitation). All included patients were treated using the MitraClip procedure. Two dimensional speckle tracking echocardiography (2DSTE) of the LA as well as of the LV could be performed in 35 patients with follow-up 2DSTE at four weeks and/or three months after MitraClip implantation. In 25.7% of patients primary mitral regurgitation was present (n=9) and in 74.3% of subjects a secondary entity of mitral regurgitation had been diagnosed (n=26). 57.1% of patients (n=20) suffered from heart failure with preserved ejection fraction (HFpEF) and 42.9% of patients (n=15) had heart failure with reduced ejection fraction (HFrEF). Global longitudinal strain (GLS) was reduced at baseline (−15.3%), at four-week (−14.5%, n=27) and at three-month follow-up (−13.9%, n=28) with no statistically significant differences indicating a sustained mechanical impairment of LV. In contrast significant deterioration was observed in the peak atrial longitudinal strain (PALS) representing LA reservoir function (15.3% at baseline vs. 11.8% at four-week follow-up, n=25, p=0.015 and 16.0% at baseline vs. 13.2% at three-month follow-up, n=25, p=0.03). Similarly to LA reservoir function LA booster function indicating left atrial active contraction was significantly reduced after MitraClip implantation (12.5% at baseline vs. 8.0% at four-week follow-up, n=10, p=0.028). Contrary to LA functional parameters LA size did not change significantly after MitraClip implantation (LA volume index at baseline 74.5 ml/m2 vs. 70.1 ml/m2 at four-week follow-up, n=27, p=0.489). Conclusion The present study revealed a deterioration of LA functional parameters (LA reservoir and LA booster function) after MitraClip insertion. It is known that severe mitral regurgitation can cause structural changes of the LA such as fibrosis. MitraClip insertion leads to a significant reduction of regurgitant volumes but structural changes of the LA may not be reversible. In addition MitraClip implantation increases afterload in the LA potentially explaining the observed deterioration of LA functional parameters. Acknowledgement/Funding None