MITRA.FR study – Percutaneous Mitral Valve Repair Offers No Benefit over Medical Treatment in Secondary Mitral Regurgitation
– Insight into the MITRA.FR study, the results of which were presented at the European Society of Cardiology Congress, Munich, Germany, 25–29 August 2018
Severe secondary (also referred to as functional) mitral regurgitation (MR) is predictive of poor clinical outcomes in patients with heart failure and reduced left ventricular ejection fraction, and is an independent risk factor for worsened survival.1,2
It is uncertain whether mitral regurgitation contributes to the poor prognosis or whether it is a consequence of left ventricular dilation and dysfunction in these patients.2
Treatment guidelines offer only low-grade evidence for the potential benefits of mitral valve repair in secondary MR, for patients who remain symptomatic despite optimized medical care. This presented a call to action for randomized clinical trials to elucidate the role of percutaneous mitral-valve repair in improving outcomes for patients with secondary MR.
The Multicentre study of percutaneous mitral valve repair MitraClip device in patients with severe secondary mitral regurgitation (MITRA-FR) is the first prospective, randomized study to assess the benefit of mitral valve repair in addition to medical treatment in patients with severe secondary MR. The primary efficacy outcome was a composite of death from any cause or unplanned hospitalisation for heart failure at 12 months.
Overall, 307 patients were randomized to treatment with either valve repair using a MitraClip or with medical treatment. Two-thirds of patients had New York Heart Association (NYHA) Class II or III heart failure, indicative of severe disease.3
Of the 152 patients randomized to the mitral valve repair arm, 14 (9.2%) had no study device implanted (implant failure or not attempted); of those that did undergo surgery, 63 (45.7%) had one device implanted, 62 (44.9%) had two devices implanted, and 13 (9.4%) had three or more devices implanted. A total of 21 of the 144 patients (14.6%) in whom implantation was attempted had periprocedural complications.3
Percutaneous mitral valve repair was performed on average 14 days after randomization, and MITRA-FR confirmed the safety and efficacy of the MitraClip device: 95.1% of patients had a reduction in MR of at least one grade. The majority of patients (91.9%) had a reduction of MR severity to mild to moderate or lower and 75.6% had a reduction to mild or none/trace.
Importantly, both mitral valve repair and medical treatment resulted in the same rate of death or unplanned hospitalization for heart failure at 12 months. No benefit with the addition of surgery to medical treatment was observed, and this finding was consistent across patient subgroups.
The conversation remains open around a potential role for mitral valve repair in patients who remain symptomatic despite optimized medical treatment. However, in the routine management of patients with secondary MR, there is no support for mitral valve repair in addition to standard of care medical treatment.
In the near future, additional evidence on the potential role of MitraClip (the Cardiovascular outcomes assessment of the MitraClip percutaneous therapy for heart failure patients with functional mitral regurgitation [COAPT] trial) in secondary MR will emerge and contribute to the discussion around optimal management strategies.
References
1. Goliasch G, Bartko PE, Pavo N, et al. Refining the prognostic impact of functional mitral regurgitation in chronic heart failure. Eur Heart J. 2018;39:39–46.
2. Trichon BH, Felker GM, Shaw LK, et al. Relation of frequency and severity of mitral regurgitation to survival among patients with left ventricular systolic dysfunction and heart failure. Am J Cardiol. 2003;91:538–43.
3. Obadia JF, Messika-Zeitoun D, Leurent G, et al. Percutaneous repair or medical treatment for secondary mitral regurgitation. N Engl J Med. 2018. doi: 10.1056/NEJMoa1805374