Impact of Intraprocedural Mitral Regurgitation and Gradient Following Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

BACKGROUND The impact of intraprocedural results following transcatheter edge-to-edge repair (TEER) in primary mitral regurgitation (MR) is controversial. OBJECTIVES This study sought to investigate the prognostic impact of intraprocedural residual mitral regurgitation (rMR) and mean mitral valve gradient (MPG) in patients with primary MR undergoing TEER. METHODS The PRIME-MR (Outcomes of Patients Treated With Mitral Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation) registry included consecutive patients with primary MR undergoing TEER from 2008 to 2022 at 27 international sites. Clinical outcomes were assessed according to intraprocedural rMR and mean MPG. Patients were categorized according to rMR (optimal result: <= 1+, suboptimal result: >= 2+) and MPG (low gradient: <= 5 mm Hg, high gradient: > 5 mm Hg). The prognostic impact of rMR and MPG was evaluated in a Cox regression analysis. The primary endpoint was 2-year all-cause mortality or heart failure hospitalization. RESULTS Intraprocedural rMR and mean MPG were available in 1,509 patients (median age = 82 years [Q1-Q3: 76.086.0 years], 55.1% male). Kaplan-Meier analysis according to rMR severity showed signi ficant differences for the primary endpoint between rMR <= 1+ (29.1%), 2+ (41.7%), and >= 3+ (58.0%; P < 0.001), whereas there was no difference between patients with a low (32.4%) and high gradient (42.1%; P = 0.12). An optimal result/low gradient was achieved in most patients (n = 1,039). The worst outcomes were observed in patients with a suboptimal result/high gradient. After adjustment, rMR >= 2+ was independently linked to the primary endpoint (HR: 1.87; 95% CI: 1.32-2.65; P < 0.001), whereas MPG >5 mm Hg was not (HR: 0.78; 95% CI: 0.47-1.31; P = 0.35). CONCLUSIONS Intraprocedural rMR but not MPG independently predicted clinical outcomes following TEER for primary MR. When performing TEER in primary MR, optimal MR reduction seems to outweigh the impact of high transvalvular gradients. (JACC Cardiovasc Interv 2024;17:1559 -1573) (c) 2024 by the American College of Cardiology Foundation.