The study found no negative effect with having a slightly smaller mitral valve opening as long as there was good reduction of the mitral regurgitation, according to a news release.
MitraClip, while used to help the mitral valve close more completely to restore blood flow through the heart, has the potential to cause mitral stenosis in which the amount of oxygen-carrying blood coming from the lungs is reduced. The valve, when placed, becomes slightly smaller, which raises the pressure gradient, creating an issue where researchers previously were unsure if patients would lose the benefit of the treatment if the gradient got too high.
COAPT, the first randomized trial to show that MitraClip was a safe treatment for patients with secondary mitral regurgitation with improved outcomes, including nearly 40% reduction in death at two years and 50% reduction in heart failure hospitalizations. The Penn researchers went to observe the patients in the COAPT trial to compare those with high gradients to those with low gradients.
The study found that even those with high gradients (previously considered too high in primary mitral regurgitation) had the same benefit in terms of reduced death and heart failure hospitalization compared to those with lower gradients. Those approved for the COAPT trial proved that the benefits of MitraClip with secondary mitral regurgitation reduction outweigh the slight increase in gradient.
Other improvements in some quality of life measures for those with higher gradients were also observed, although further studying is needed to assess if the same would be true during exercise or other activities. The study does not necessarily prove that it is safe for physicians to add another MitraClip during a procedure, as it was retrospective and not randomized.
“This data is very reassuring for physicians who place MitraClips in patients with secondary mitral regurgitation. It demonstrates that the benefits of MR reduction in patients with heart failure were maintained even when mild-to-moderate mitral stenosis, which can be caused by a narrowing of the mitral valve, occurred after MitraClip,” said lead author Dr. Howard C. Herrmann, who serves as the John Winthrop Bryfogle Professor of Cardiovascular Diseases in the Perelman School of Medicine at the University of Pennsylvania and Health System Director for Interventional Cardiology.