The prognostic impact of intra-procedural mitral valve gradient following transcatheter edge-to-edge repair for primary mitral regurgitation

Abstract Background/Introduction The impact of intra-procedural mitral valve gradient following transcatheter edge-to-edge repair (TEER) in primary mitral regurgitation (MR) is a matter of controversial debates. Purpose The aim of this study was to investigate the prognostic impact of intra-procedural mean mitral valve gradient (MPG) in patients with primary MR undergoing TEER. Methods The PRIME-MR registry included consecutive patients with primary MR undergoing TEER from 2008-2022 at 27 international sites. Clinical outcomes were assessed according to intra-procedural mean MPG measured at the end of the procedure by transesophageal echocardiography. The evolution of mean MPG from intra-procedural to discharge and follow-up was documented. Baseline characteristics and clinical outcomes of patients were investigated according to intra-procedural mean MPG using a cut-off of 5mmHg (low MPG: ≤5mmHg, high MPG: >5mmHg). The prognostic impact of intra-procedural mean MPG was evaluated in multivariable Cox regression analysis. The primary endpoint was 2-year all-cause mortality or heart failure (HF) hospitalization. Results Intra-procedural MPG was available in 1,516 patients (median age 82 years [IQR 76.0, 86.0], 55.1% male). Patients with high intra-procedural MPG presented with less atrial fibrillation and less severe MR but were more symptomatic at baseline than patients with low MPG. Moreover, patients with high intra-procedural MPG had higher baseline MPG and smaller LV dimensions (LVEDV and LVESV). The rate of patients with mean MPG >5mmHg increased from intra-procedural (18.3%) to discharge (31.3%), while remaining stable thereafter (1-year follow-up: 30.9%; last follow-up: 29.6%). At 1-year follow-up the rate of patients presenting with New York Heart Association (NYHA) functional class I or II did not differ between patients with low (82.3%) and high MPG (83.6%, p=0.93). Kaplan-Meier analysis according to mean MPG showed no difference between patients with low and high MPG for the primary endpoint (32.4% vs. 42.1%, p=0.12), as well as for the single endpoints of all-cause mortality (22.3% vs. 27.7%, p=0.47) and HF hospitalization (17.6% vs. 27.5%, p=0.087) through 2 years (Figure 1). Unadjusted spline analyses were provided to depict the prognostic impact of continuous intra-procedural MPG (Figure 2). Following multivariable Cox regression neither MPG >5mmHg (HR 0.91, 95%-CI 0.56-1.49, p=0.72), nor continuous MPG (HR 1.05, 95% CI 0.96-1.15, p=0.28) were independently associated with adverse clinical outcomes. Conclusions Based on a large international cohort of patients with primary MR undergoing TEER, intra-procedural mean MPG did not significantly affect clinical and functional outcomes at 2 years. The long-term impact of elevated post-procedural MPG warrants further investigation.Figure 1Figure 2