Percutaneous transseptal mitral valve replacement (TMVR) with the SAPIEN M3 System significantly reduced mitral regurgitation (MR) severity, improved functional status and quality of life, and achieved low mortality and heart failure hospitalization rates at one year, according to results from the ENCIRCLE trial presented by Dr. David Daniels, Dr. Mayra Guerrero, and Dr. John Webb on behalf of the ENCIRCLE investigators at TCT 2025.
The ENCIRCLE trial is the first pivotal study to evaluate outcomes of a fully percutaneous, transseptal TMVR system in patients with symptomatic MR who are not suitable candidates for surgery or other commercially available transcatheter treatment options. The trial enrolled up to 300 patients, all of whom had moderate-to-severe (≥3+) MR, New York Heart Association (NYHA) class II or greater symptoms, and were deemed unsuitable for existing treatment approaches due to anatomic or clinical considerations.
The primary endpoint was a composite of all-cause mortality or heart failure hospitalization (HFH) at one year, compared against a prespecified performance goal of 45%. Follow-up was scheduled at 30 days, 6 months, 1 year, and annually through five years.
Among 299 treated patients (mean age 75.5 years; 51% male), comorbidities were common, including hypertension (84.3%), diabetes (34.4%), atrial fibrillation (69.9%), and chronic kidney disease (mean eGFR 58 mL/min/1.73m²). The mean Society of Thoracic Surgeons (STS) score for mitral valve replacement was 6.6, with 28.8% of patients having an STS score ≥8, indicating high surgical risk.
At one year, the primary composite endpoint occurred in 25.2% of patients (95% CI: 20.6–30.6; p<0.0001 vs performance goal), well below the 45% benchmark. Individually, all-cause mortality was 13.9%, and heart failure hospitalization occurred in 16.7% of patients. The 30-day all-cause mortality rate was only 0.7%, approximately one-tenth of the expected rate based on STS-predicted surgical risk.
Echocardiographic data demonstrated durable correction of MR. More than 95% of patients achieved mild or less MR (≤1+) at both 30 days and one year (p<0.0001 for both time points). These improvements were accompanied by sustained gains in NYHA class and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores, reflecting enhanced functional capacity and quality of life.
Investigators emphasized that the SAPIEN M3 system achieved predictable procedural outcomes with a fully percutaneous, transseptal approach, avoiding the need for open surgery. The trial’s findings also underscored the device’s safety, with observed mortality and heart failure hospitalization rates markedly below the pre-specified thresholds.
The ENCIRCLE trial demonstrated that transseptal TMVR with the SAPIEN M3 System provides a safe and effective treatment option for patients with severe symptomatic MR who are not candidates for surgical or other transcatheter interventions. The results showed durable MR reduction, improved clinical status, and lower-than-expected mortality, supporting the system’s potential as a new therapeutic alternative in advanced mitral valve disease management.
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