Impact of proportionate versus disproportionate mitral regurgitation on acute procedural changes and clinical outcomes following transcatheter mitral valve repair

Abstract

Abstract Background Transcatheter mitral edge-to-edge repair (TEER) with MitraClip offers a less invasive alternative for patients with severe, symptomatic mitral regurgitation (MR) who are considered high risk for surgery. However, patient selection for TEER remains challenging given the variability in underlying MR pathology and current discordance among studies regarding predictors of procedural efficacy and clinical outcomes. Purpose This study aimed to assess acute procedural changes and long-term outcomes in patients who underwent TEER according to the proportionality of MR, defined as the ratio of the effective regurgitant orifice area (EROA) and left ventricular end-diastolic volume (LVEDV). Methods We analyzed patients who underwent TEER at our institution between 2014 and 2020 with available biplane left ventricular volume measurement. Relevant clinical comorbidities, demographics, and anthropometrics, along with pertinent pre- and post-procedural echocardiogram measurements, were obtained by review of the electronic medical record. The EROA to LVEDV index was calculated for all patients who were then stratified by quartiles. Patients with an EROA/LVEDV index in the lowest quartile were defined as having the most proportionate MR and those with an index in the highest quartile were defined as the most disproportionate MR. Baseline and post-TEER parameters were used to assess acute procedural and longitudinal outcomes. Results Baseline clinical and echocardiographic parameters of the 230 subjects according to quartile are shown in the table. Following TEER, there was a larger reduction in the left ventricular end-diastolic diameter and increased MR reduction with increasingly disproportionate MR (p=0.03 and p=0.05, respectively). The change in ejection fraction pre- versus post-TEER did not significantly differ across groups (p=0.64). Median follow up time was 1.7 (0.7–3.5) years; mortality occurred in 77 patients (33.5%) and heart failure hospitalizations occurred in 20 patients (8.7%) during follow up. No significant difference in all-cause mortality or post-procedural heart failure hospitalizations was identified across groups. Conclusions In our series, patients with proportionate MR were similarly symptomatic to those with disproportionate MR but had less severe MR with increased comorbidities. Post-TEER MR grade was similar between groups. Longer-term follow up in larger groups of patients is needed to determine the clinical implications. Funding Acknowledgement Type of funding sources: None.