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Mitral Valve Clip: From Anecdote to Explosive Development

— COAPT trialist Michael Rinaldi, MD, on why "we've only scratched the surface"

MedpageToday

The highly-anticipated COAPT trial has provided decisive evidence of the effectiveness of transcatheter mitral valve repair in patients with secondary mitral regurgitation.

I, along with many of my peers, expected that the COAPT trial would affirm the effectiveness of the MitraClip device in that patient population. In my own practice, I've seen cases like one 67-year-old man with heart failure who was on a ventilator when I met him, too sick for open-heart surgery, no longer responding to medications, and near death. Transcatheter mitral valve repair with the clip device presented a minimally-invasive, less-risky treatment alternative. Just 2 days after his procedure was complete, he returned home. At his 2-year check-up, he no longer struggled to breathe and hadn't visited the hospital since.

But I was truly surprised by the magnitude of our results: the procedure cut heart failure hospitalizations in half and reduced mortality by nearly 40% over the course of 2 years. Patients experienced major improvements in their quality of life and ability to perform day-to-day tasks, with many of these benefits emerging within the first 30 days of treatment.

The COAPT results differ from other, recent research into transcatheter mitral valve repair, such as the Mitra-FR study, which also studied patients with secondary mitral regurgitation. The key difference: COAPT studied patients who had truly exhausted other treatment options. The first line of therapy for secondary mitral insufficiency is to maximally treat the underlying heart failure and ventricular dysfunction with standard medications that are known to improve heart function and save lives.

In the Mitra-FR study, it is not clear that patients were on optimal medical therapy first. COAPT mandated maximal medical therapy and only patients who failed medical therapy were entered into the study. It is this group who will see the greatest benefit from transcatheter mitral valve repair. Additionally, it's worth noting that COAPT engaged more than double the number of trial patients, when compared with Mitra-FR.

The strength of these results should settle the scientific question surrounding the value of this therapy in patients with this condition who have exhausted other treatment options.

As a co-author on the New England Journal of Medicine paper, I hope that its results will persuade more hospitals to train their physicians to conduct this important, minimally invasive therapy. Just as importantly, I believe that the evidence in this trial should spark further research into new catheter-based technologies to treat a greater range of heart valve conditions.

My institution has been working on minimally invasive heart valve treatments for more than a decade and is one of the nation's highest-volume centers for catheter-based heart valve therapies. But across the country, there are a limited number of operators skilled in this procedure. I hope that the COAPT trial will inspire other hospitals to explore transcatheter mitral valve repair as an alternative therapy and train more physicians to perform this procedure.

But training is not enough -- we also need more research into catheter-based heart valve treatments. While COAPT fills a crucial gap in clinical data to describe how patients with secondary mitral regurgitation respond to mitral valve repair, I believe we've only scratched the surface. I challenge my colleagues, along with device developers, to pursue more research into catheter-based treatments and realize their potential for a greater range of heart valve conditions.

Efforts are underway to advance the field. We are investigating a variety of new approaches to treat mitral insufficiency through clinical trials. These include a registry of the next generation MitraClip device, with longer arms for better tissue apposition, and a clip-like alternative called PASCAL, which has longer and wider arms for better tissue apposition and independent arm function for individual leaflet grasping. Beyond edge-to-edge technologies, a study I am involved with is investigating a transcatheter-delivered annular band, Cardioband, which simulates a surgeon's annular ring for the treatment of secondary mitral regurgitation. Finally, the SUMMIT clinical trial of the Tendyne transcatheter mitral valve replacement technology is underway.

The field of transcatheter mitral therapies is exploding. The extremely-positive COAPT trial results are an important signal that we are headed in the right direction.

Michael Rinaldi, MD, is an interventional cardiologist at Atrium Health's Sanger Heart & Vascular Institute in Charlotte, North Carolina.