Investigators of a trial comparing transcatheter edge-to-edge repair (TEER) with surgery in patients with heart failure and secondary mitral regurgitation (MR) say that the results of their study—MATTERHORN—should prompt a reappraisal over guideline recommendations on the use of the transcatheter therapy in these patients.
Current European guidelines “somehow infer that surgery would be the procedure of choice”, said Volker Rudolph (Heart and Diabetes Center NRW, Bad Oeynhausen, Germany), presenting the MATTERHORN results at the 2024 European Society of Cardiology (ESC) congress (30 August–2 September, London, UK) where he acknowledged that, at present, TEER is only recommended for those deemed ineligible for surgery.
MATTERHORN, an investigator-initiated trial conducted at 16 centres in Germany, randomised 210 patients to undergo either TEER using the MitraClip (Abbott) device, compared to surgical mitral valve repair or replacement.
Rudolph reported that there was no significant difference in the primary composite endpoint—death, heart failure hospitalisation, mitral reintervention, assist device implantation and stroke—at one year, which occurred in 16.7% of patients in the TEER group and 22.5% in the surgical group (p<0.01 for non-inferiority).
The secondary endpoint, recurrence of MR grade ≥3 at one year also demonstrated non-inferiority of the transcatheter treatment, occurring in 8.9% of patients in the TEER group compared to 1.5% in the surgical group (p=0.091), whilst 73.2% of patients in the TEER group and 87.3% of patients in the surgical group had MR grade ≤1 after one year.
Finally, Rudolph reported that the primary safety endpoint occurred in significantly more patients in the surgical group (54.8%) than in the TEER group (14.9%; p<0.001), which was largely driven by more major bleeding (29% vs. 3%, respectively), all reinterventions (19% vs. 8%) and new-onset atrial fibrillation (AF, 33% vs. 9%).
“We know that this condition is associated with adverse outcomes in patients with heart failure—it more or less doubles the mortality of these patients. We have also seen now more data from other trials that treatment of this condition with transcatheter edge-to-edge repair can improve the prognosis of these patients,” said Rudolph.
“In patients with heart failure and secondary mitral regurgitation, intervention with edge-to-edge repair is non-inferior to surgery regarding clinical efficacy and has a much better safety profile,” he added of the overarching message of the trial. “We think that these results may extend the indication for interventional mitral repair to patients with secondary mitral regurgitation who are actually eligible for surgery.”
Despite the trialists’ enthusiasm over the results, critics of MATTERHORN have urged caution when interpreting the findings. Cardiac surgeon Joanna Chikwe (Smidt Heart Institute at Cedars-Sinai, Los Angeles, USA) acted as the discussant for the study at ESC 2024, and raised a number of points that she felt could limit the applicability of the research.
“The questions I would want to ask myself if I had a patient sitting in front of me in the office [are]: is this trial unbiased? Are the patients representative of my practice? Was the control treatment—surgery—standard of care? And, what can we decide based on 12-month data?” Chikwe said.
Of the short-term nature of the trial’s endpoints, Chikwe commented that surgery has a “hazard phase” and that the treatment’s effects are often seen late, potentially altering the perception of the trial at 12 months. Rudolph responded that longer term follow-up from the trial is being conducted.
Chikwe also argued that the trial included a wide margin for non-inferiority, which was explained by the trialists as being necessary due to the study’s sample size. “I would say that the study design is unfortunately not unbiased, it is a non-inferiority design with short follow-up, variation in the control arm, crossover and endpoints that favour TEER,” Chikwe commented, adding: “We need to do more to treat this disease of the ventricle, but the secret is not treating the leaflets.”
Findings of the study have been published in the New England Journal of Medicine.
