For patients with severe mitral regurgitation (MR) who are unsuitable for surgery or transcatheter edge-to-edge repair (TEER), therapeutic options are limited. The prospective, single-arm ENCIRCLE trial evaluated the 1-year outcomes of a novel percutaneous transseptal transcatheter mitral valve replacement (TMVR) system in this challenging patient population.¹
The SAPIEN M3 system (Edwards Lifesciences) is a percutaneous TMVR device delivered via a transseptal approach, designed to provide a new treatment avenue for individuals with severe, symptomatic MR.²
The ENCIRCLE trial (NCT04153292) was a prospective, multicentre, single-arm pivotal study conducted at 56 centres across six countries. The trial enrolled 299 adult patients with symptomatic moderate-to-severe or severe MR who were deemed unsuitable for conventional surgery or TEER by a multidisciplinary heart team. The median age of the cohort was 77 years, and the mean Society of Thoracic Surgeons (STS) predicted risk of 30-day mortality for mitral valve replacement was 6.6%.
The primary endpoint was a non-hierarchical composite of all-cause mortality and rehospitalisation for heart failure at 1 year. This was compared against a prespecified performance goal of 45%.
At 1 year, the primary endpoint rate was 25.2% (95% CI 20.6–30.6), which was significantly lower than the performance goal of 45% (p<0.0001). The procedure demonstrated a strong safety profile, with no intraprocedural deaths, no conversions to open-heart surgery, and no instances of left ventricular outflow tract obstruction that caused haemodynamic compromise.
Median follow-up was 1.4 years, with data available for 95% of patients at 30 days and 81% at the 1-year mark.
The findings from the ENCIRCLE trial suggest that percutaneous transseptal TMVR with the SAPIEN M3 system is a safe and effective procedure that successfully reduces mitral regurgitation while demonstrating low rates of mortality and complications. The results support the use of this TMVR system as a viable therapeutic option for a high-risk patient group with limited alternatives.
The ENCIRCLE trial is ongoing, and further follow-up will provide additional data on the long-term durability and clinical outcomes associated with this novel intervention.
This study was funded by Edwards Lifesciences.
References
1. Guerrero ME, Daniels DV, Makkar RR, et al. Percutaneous transcatheter valve replacement in individuals with mitral regurgitation unsuitable for surgery or transcatheter edge-to-edge repair: a prospective, multicountry, single-arm trial. Lancet 2025. https://doi.org/10.1016/S0140-6736(25)02073-2
2. Webb JG, Murdoch DJ, Boone RH, et al. Percutaneous transcatheter mitral valve replacement: first-in-human experience with a new transseptal system. J Am Coll Cardiol. 2019;73:1239-1246. https://doi.org/10.1016/j.jacc.2018.12.083
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