Current position with the MitraClip in Europe

Find out more about the session that will be held at PCR London Valves here.

An interview with Olaf Franzen, Course Director and Interventional cardiologist, University Hospital, Copenhagen

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Can you summarize the main findings of the recent EVEREST II Trial?

The multicentre randomised controlled EVEREST II trail compared percutaneous therapy versus surgical treatment in moderate or severe mitral regurgitation. Patients were randomized in a 2:1 ration either to MitraClip therapy or surgical therapy. In order to be included in the trial the mitral valve of the patients had to meet strictly predefined valve suitability criteria. Patients with a high surgical risk were excluded. Primary endpoints were composite endpoints of efficacy and safety. Secondary endpoints were defined in the field of ventricular remodelling and clinical outcome. In the trial, 186 patients have been treated with MitraClip therapy and 93 with surgery. Forty-seven centres took part in the EVEREST trials. Most of patients had degenerative mitral regurgitation. In comparison to surgery, the Mitraclip therapy was less effective (55% vs. 73%, P=0.007), but was superior in regard to safety (15% vs. 48%, p < 0,001). The difference in efficacy was mainly driven by the need of conversion to surgery in the MitraClip group. The difference in safety was mainly driven by the rate of transfusion ≥2 U in the surgical group. In both groups, ventricular seize, functional class and quality of life improved at 12 month as compared to baseline.

What was the rate of crossover to the surgical arm from the device arm?

Twenty per cent of the patients in the MitraClip group needed surgery because of mitral valve dysfunction. Two per cent in the surgical arm needed reoperation.

Where do you see the role of the MitraClip at the moment?

If we look at the EVEREST data, it can be assumed that many sites have not treated more than three patients. This is an important point as this therapy definitely has a learning curve. In experienced centres the success rate is much better than in the EVEREST trials. But even though it can be speculated that the EVEREST centres would have better results than in the trial, I think, good surgical candidates should be treated with the MitraClip therapy only in exceptional cases. It is a good option for patients with a high surgical risk.

Which patient population do you think benefits most from the MiraClip rather than surgical intervention (functional regurgitation)?

While the surgical results in degenerative mitral regurgitation are excellent, the published surgical results in functional mitral regurgitation are less convincing. Recurrence of mitral regurgitation seems to be a problem. Many heart failure specialists feel that surgery is not a good option for their patients with functional mitral regurgitation and impaired left ventricular function. The guidelines do not favour surgery for this group. If medical therapy and CRT fail, less invasive treatment options for mitral regurgitation might be a solution in this vulnerable group. The European experience with the MitraClip therapy, as well as the continuous access in US, demonstrates first promising results in functional mitral regurgitation. Therefore the group of patients with functional mitral regurgitation might benefit the most from the MitraClip therapy. Of course patients who also present with degenerative mitral regurgitation, suitable mitral valve morphology and a high surgical risk have a possible solution with this therapy.

If the MitraClip has been unsuccessful can these patients then go onto have mitral valve surgery?

We know that most of the treated patients have a high surgical risk. Naturally it remains high after an unsuccessful MitraClip. Technically, a Mitraclip can be opened again during heart surgery. Afterwards, the surgical technique should not be influenced if the leaflets are not harmed. But in some patients, pronounced fibrosis might encapsulate the clip. This fibrosis might spread towards the leaflets. In such patients or when the valve is harmed, surgical repair of the leaflets might be difficult or even impossible. Than valve replacement is left as an option. In principle, the surgical option is preserved. Looking on the EVEREST experience, it seems that even most of the patients can get the kind of surgical treatment, which would have be chosen before implantation of a MitraClip. But in the individual patient, we should take the possible risk of loosing the option for later mitral valve repair into the equation. In a younger patient with a degenerative mitral regurgitation and a low surgical risk, this seems to be unacceptable, while in another individual patient, a relative low risk can weight the possible benefit.

Is there a role for comparing the MitraClip in comparison to medical therapy alone in a randomised controlled trial?

Given the promising MitraClip results from retrospective analysis and registries, this would be the next logical step. A Danish study just published in June in the European Journal of Heart Failure demonstrated that in a 3,000 patients with heart failure, the prognostic importance of mitral regurgitation for patients with severely impaired left ventricular function. In my eyes we definitely have to conduct a randomised MitraClip heart failure trial, one arm with optimal medical treatment and CRT if indicated, the other arm with additional percutaneous treatment of their mitral regurgitation. In fact a first randomised trial including centres from Netherlands, Sweden, Germany, Denmark and possibly also UK is in preparation.

Where do we go from here? Are there newer devices currently being developed? How do they differ and do you think they will improve outcomes?

The MitraClip – with more than 3,000 patients already treated – demonstrated that percutaneous treatment of mitral regurgitation is a success story. But it seems to be logical that we need a broader armamentarium to individualize the approach. A surgeon has more than only one technique to treat mitral regurgitation. Fortunately, the technical innovation in the field of catheter-based treatment of mitral regurgitation is impressive. Devices addressing the mitral ring, the leaflets and the left ventricular walls are on its way. Many of them are promising; most of them are in an early stage. I my opinion, the next milestone will be the first series of percutaneous mitral valve replacement. Valve replacement will offer a treatment option for patients in who repair techniques are not suitable anymore. But we should not be just enthusiastic about the innovative technologies. The patient, not just the valve, must continue to be in the centre of our interest. Many principle questions, especially in the field heart failure patients with mitral regurgitation, are still open. In this field, new technologies possibly only improve the outcome if they are embedded in a program that is driven by a common team of heart failure specialists, echocardiographers, cardiac surgeons, nurses, anaesthetists, ICU specialists, and interventionalists.

Find out more about the session that will be held at PCR London Valves here.

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