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Transcatheter mitral valve repair using the MitraClip can be performed safely with a high rate of success in high-risk patients with degenerative or functional mitral regurgitation (MR), according to results from a large European registry published in the September 2, 2014, issue of the Journal of the American College of Cardiology. US physicians still question the treatment’s role among patients with functional MR, however, and are awaiting the results of clinical trials.

MitraClip Successful for Both Types of MR

The procedure had a high success rate for degenerative and functional MR. Rates of acute procedural success rate and 1-year mortality were similar between the 2 groups, although there was a trend toward higher risk of in-hospital mortality among patients with degenerative MR. Those with functional MR were more than twice as likely to require repeat hospitalization because of heart failure within a year (table 1).

Table 1. Outcomes of MitraClip Repair

The procedure reduced MR overall. At baseline, MR was severe in 86.1% and moderate in 13.2% overall. After the procedure, MR was classified as “no/mild” in 72.8% at discharge and in 58.6% at 1 year.

Good Option for High-Risk Patients

In an accompanying editorial, David R. Holmes Jr, MD, and Charanjit S. Rihal, MD, of the Mayo Clinic (Rochester, MN), make clear that the MitraClip is for high-risk patients only.

“Patients treated with this technology are elderly, highly symptomatic, and have a high logistic EuroSCORE (20.4 ± 16.7%),” they wrote. “These are not the sort of patients for whom there is a long roster of cardiovascular surgeons waiting outside the room to talk about scheduling for a surgical date.”

Robert O. Bonow, MD, of the Feinberg Cardiovascular Research Institute and Northwestern University Medical School (Chicago, IL), agreed in a telephone interview with TCTMD. But he is less convinced than the study authors of the role of the MitraClip in patients with functional MR. 

For Functional MR, ‘Still Some Equipoise’  

“With [functional MR],” Dr. Bonow said, “the primary disease is in the muscle, not the vessel, and there’s always been uncertainly as to whether treating the regurgitation leads to a better outcome because you’re still dealing with left ventricular dysfunction. The guidelines say you have to treat that first with optimal medical therapy and, in appropriate patients, with resynchronization therapy, before considering mitral valve surgery.

The current study suggests “an ongoing problem” exists after MitraClip treatment for functional MR patients, he noted. “They are still sick. They still have left ventricular dysfunction, and the rehospitalization rate is still quite high. So, there’s still some equipoise as to whether this is a good approach for treating [functional MR] from the beginning or whether we still want to reserve it for patients who fail medical therapy.”

Two clinical trials in this area are ongoing: COAPT and RESHAPE-HF.

Dr. Di Mario agreed that trials exploring the role of the MitraClip in functional MR are warranted, but he said the current lack of US approval for this indication is a mistake.

I am afraid the United States will be limited by the approval [of the MitraClip] only for degenerative valve disease,” he told TCTMD in an email. Without operators having the opportunity start out by treating functional MR—a comparatively easier procedure—they are unlikely to build sufficient expertise necessary to treat more challenging anatomies, Dr. Di Mario concluded.

1. Nickenig G, Estevez-Loureiro R, Franzen, et al. Percutaneous mitral valve edge-to-edge repair: in-hospital results and 1-year follow-up of 628 patients of the 2011-2012 pilot European sentinel registry. J Am Coll Cardiol. 2014;64:875-884.

2. Holmes DR, Rihal CS. Snake eyes [editorial]. J Am Coll Cardiol. 2014;64:885-886.

Disclosures:

• Drs. Di Mario, Bonow, Holmes, and Rihal report no relevant conflicts of interest.

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