Comparison of Transcatheter Edge-to-Edge Mitral Valve Repair for Primary Mitral Regurgitation Outcomes to Hospital Volumes of Surgical Mitral Valve Repair

Background Transcatheter edge-to-edge mitral valve (MV) repair (TEER) is an effective treatment for patients with primary mitral regurgitation (MR) at prohibitive risk for surgical MV repair (MVr). High volume MVr centers and high volume TEER centers have better outcomes than low volume centers, respectively. However little is known about whether MVr volume, and specifically complex MVr volume, predicts TEER outcomes. We hypothesized that high volume MV surgical centers would have superior risk-adjusted outcomes for TEER than tlow volume centers. Methods We combined data from the ACC/STS TVT registry and the STS adult cardiac surgery database. Complex MVr, defined as leaflet resection or artificial chords with or without annuloplasty was evaluated as a continuous variable and as pre-defined categories (<25, 25-49 and ≥ 50 MV repairs/year). A generalized linear mixed model was used to evaluate risk-adjusted in-hospital/30-day mortality, 30 day HF readmission and TEER success (MR ≤ 2+ and gradient < 5 mmHg). Results The study comprised 41,834 patients from 500 sites. TEER mortality at 30-days was 3.5% with no significant difference across MVr volume on unadjusted (p=0.141) or adjusted (p=0.071) analysis of volume as a continuous variable. One-year mortality was 15.0% and was lower for higher MVr volume centers when adjusted for clinical and demographic variables (p=0.027). HF readmission at one year was 9.4% and was statistically significantly lower in high volume centers on both unadjusted (p=0.017) or adjusted (p-0.015) analysis. TEER success was 54.6% and was not statistically significantly different across MV surgical site volumes (p=0.4271). Conclusions TEER can be safely performed in centers with low volumes of complex MV repair. However, one-year mortality and HF readmission are superior at centers with higher MVr volume.