# The MATTERHORN trial: Percutaneous MitraClip vs surgical repair in heart-failure-related secondary mitral regurgitation

## TL;DR

The MATTERHORN trial compared MitraClip and surgical repair for heart failure-related mitral regurgitation, finding similar effectiveness but fewer short-term risks with MitraClip.

## Contribution

This trial provides the first direct comparison of transcatheter and surgical repair for secondary mitral regurgitation in high-risk patients.

## Key findings

- M-TEER showed noninferiority to surgery for key outcomes at 1 year.
- M-TEER had fewer major adverse events within 30 days but higher MR recurrence.
- Surgical repair had lower MR recurrence but higher short-term risks.

## Abstract

Introduction: Functional mitral regurgitation (FMR) is a common complication of heart failure and is associated with poor prognosis and increased morbidity and mortality. Surgical mitral valve repair (MVRe) and MitraClip transcatheter edge-to-edge repair (M-TEER) are used to improve FMR, however, there has not been sufficient comparison between the benefits of both approaches. The MATTERHORN trial aimed to compare the efficacy and safety outcomes of percutaneous versus surgical repair in high-risk patients with heart failure and FMR, to determine the noninferiority of transcatheter edge-to-edge therapy in this population.

Study and results: 208 patients were randomized in a 1:1 ratio to either M-TEER with MitraClip device or surgical mitral valve repair or replacement. The average age was 70.5 ±  7.9 years, 39.9% were female, mean LVEF was 43.0 ±  11.7%, 85.7% of patients had NYHA class III or IV, 96.0% had Mitral regurgitation grade ≥3, 38.2% had grade 4+, median effective regurgitant orifice area was 0.22cm2 and the mean regurgitant fraction was 57.0 ±  21.0%. Successful repair was seen in 96.1% in the M-TEER group and 98.6% in the surgery group. At 1 year, at least one primary endpoint event (death, hospitalization for heart failure, mitral valve re-intervention, implantation of an assist device, or stroke) occurred in 16.7% of the M-TEER group and 22.5% of the surgery group. All-cause death occurred in 8.3% and 10.3% of patients, respectively. Recurrence of MR grade ≥3 at 1 year and mitral valve reintervention was 8.9% and 5% in the M-TEER group and 1.5% and 2% in the surgical group, respectively. Overall, 41.0% of the patients in the intervention group and 77.3% in the surgery group had at least one adverse event, of which 35% and 66%, respectively, were serious.

Lessons learned: Transcatheter edge-to-edge repair demonstrated noninferiority to surgery for a composite of death, rehospitalization for heart failure, stroke, reintervention, or assist device implantation at 1-year. M-TEER exhibited significantly fewer major adverse events within 30 days post-procedure, albeit with a slightly higher MR recurrence rate at one year. This study underscores the potential of M-TEER as a less-invasive, yet effective, alternative to surgery for FMR, mitigating surgical risks and offering a faster recovery path, especially for patients deemed unsuitable for surgery. However, long-term data is crucial for guiding policies.