MATTERHORN - Transcatheter versus surgical mitral valve repair in patients with heart failure and secondary mitral regurgitation
Reported from ESC Congress 2024
Yohei Ohno provides his takeaways from the results of the MATTERHORN trial presented by Volker Rudolph at the ESC Congress 2024 in London.
Summary of the MATTERHORN trial. Courtesy of Yohei Ohno. Source: PCRonline.com
Why this study? The rationale/objective
Current guidelines (both European and American) recommend either transcatheter edge-to-edge repair (TEER) or mitral valve surgery for intervening patients with heart failure and secondary mitral regurgitation (MR). However, there was no direct comparison among these therapies with these populations.
The objective of MATTERHORN trial was to compare TEER vs. surgery on efficacy and safety outcomes in patients with secondary MR. It was presented in a Hot Line Session at ESC Congress 2024 with simultaneous publication in the NEJM.
How was it executed? The methodology
210 patients were randomized in a 1:1 fashion to either TEER with MitraClip or mitral valve surgery (repair or replacement). Inclusion criteria were patients with secondary MR with symptomatic heart failure (NYHA > 2) despite guideline-directed medical therapy and LVEF > 20% who were deemed high surgical risk by the heart team. This study was conducted in 16 centers in Germany.
The primary efficacy endpoint was a composite of death, hospitalization for heart failure, mitral-valve reintervention, implantation of an assist device, or stroke within 1 year after the procedure. The primary safety endpoint was a composite of major adverse events within 30 days after the procedure. The mean age of patients was 70.5 years; 39.9% were women, mean LVEF was 43%, and median effective regurgitant orifice area was 0.22cm2.
What is the main result?
- Within 1 year, the primary efficacy endpoint was noted in 16/96 (16.7%) patients in the TEER group and 20/89 (22.5%) patients in the surgery group (odds ratio 0.69 [95% CI 0.33-1.44], p=0.32) which met the non-inferiority criteria (p<0.001). The breakdowns of the primary efficacy endpoint were comparable between the two groups.
- Primary safety endpoint event occurred in 15/101 patients (14.9%) in the TEER group and in 51/93 patients (54.8%) in the surgery group (estimated mean difference, −40 percentage points; 95% CI, −51 to −27; p<0.001).
- Recurrence of MR grade 3+ (moderate-to-severe) or 4+ (severe) at 1 year which was a key secondary endpoint, was observed in 7/79 patients (8.9%) in the TEER group and in 1/65 patients (1.5%) in the surgery group (estimated mean difference, 7 percentage points; 95% CI, 0 to 14; p = 0.02 for noninferiority).
Critical reading and relevance for clinical practice
The MATTERHORN trial is the first RCT to directly compare mitral TEER vs. surgery in patients with heart failure and secondary mitral regurgitation who are suitable for mitral valve surgery. It is an important study to demonstrate that mitral TEER could be considered as a therapeutic option in high-surgical risk patients. However, this trial result should be interpreted with caution, as it also has several limitations.
- Relatively small trial which took a long period (2015-2022) to enrol the patients and fewer events than anticipated (16.7% for TEER group, 22.5% for surgery group, but expected incidence was 35% in both arms).
- Non-inferiority margin was 17.5% which was wide.
- Additional procedure was possible for surgical group (18.5% concomitant MAZE, 10% concomitant tricuspid annuloplasty) which could have impacted the result.
- 1 year is considered to be short to assess the late treatment effect of surgery.
- Treatment variation in both arms: All generation MitraClip devices (G1 to G4) were used, mainly G2 and G3. 28% replacement and 8% reoperation in index admission for surgical group.
Nevertheless, the MATTERHORN trial is the very first important RCT to demonstrate that mitral TEER was non-inferior to surgery with respect to a composite of death, heart failure hospitalization, reintervention, implantation of an assist device, or stroke at 1 year with a favourable safety profile among patients with heart failure and secondary mitral regurgitation.
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