Persistent Functional Mitral Regurgitation 1 Year after Left Ventricular Assist Device Implantation: Prognostic Impact and Preoperative Echocardiographic Features

Purpose Despite mechanical unloading after left ventricular assist device (LVAD) implantation, uncorrected FMR persists in up to 30% of LVAD recipients. Nevertheless, pre-operative echocardiographic features resulting in persistent MR after LVAD implantation and its prognostic impact remain unkown. Methods 94 consecutive patients underwent LVAD implantation at our institution between 2015 and 2019, whereof 47 patients showed moderate to severe MR prior to LVAD implantation. One year after LVAD implantation 10 patients showed persistent MR (MR-group), in contrast to 23 patients with less than moderate MR (Control-group). Apart from clinical baseline and follow-up parameters, preoperative echocardiographic features, functional exercise capacity 1 year after LVAD implantation and overall survival rates were retrospectively analyzed. Results Predominantly male patients (80.9%) with a mean age of 53 years were mainly treated with the Medtronic HVAD device (76%). Baseline characteristics including the severity of LV and RV dysfunction (LVEF 19%, TAPSE 14mm MR-group vs. LVEF 19%, TAPSE 16mm Control-group) were comparable between both study-groups. There was no difference regarding preoperative LV dilatation (LVEDD 78mm MR-group vs. LVEDD 75mm Control-group; p=0.67). We found significantly increased parameters of mitral leaflet-tethering prior to LVAD implantation within the MR-group (Tenting-height: 11.5mm vs. 7.5mm; p=0.03; Tenting-area: 244mm² vs. 178mm²; p=0.04). Tethering of the anterior mitral leaflet (AML) was particularly increased in the MR-group (p=0.02). 12 months after LVAD implantation patients within the MR-group showed a significantly reduced exercise capacity (6-minute walk test: 293m vs. 439m; p=0.04). Overall survival was significantly impaired in the MR-group in comparison to the Control-group (40% vs. 91%; p=0.002). Conclusion LVAD recipients with persistent MR despite mechanical unloading showed significant echocardiographic signs of mitral leaflet tethering prior to LVAD implantation. Furthermore, persistent MR 12 months after LVAD implantation was associated with a reduced exercise capacity and an impaired overall survival. If correction of preoperative MR improves post implant survival needs to be shown in future studies.