Percutaneous mitral-valve repair appears futile
Percutaneous mitral-valve repair with MitraClip failed to improve clinical outcomes in chronic heart failure (HF) patients with severe secondary mitral regurgitation, according to the MITRA-FR study presented at the European Society of Cardiology (ESC) Congress 2018.
“Our study showed that reduction in mitral regurgitation achieved with percutaneous mitral-valve repair did not translate into a clinical benefit in HF patients,” said principal investigator Professor Jean-Francois Obadia of the Civil Hospices of Lyon, France. “There is no reason to perform this procedure in all HF patients with secondary mitral regurgitation. Further randomized trials are needed to identify subgroups of patients who may benefit from percutaneous mitral-valve repair.”
The study included 304 patients who had symptomatic CHF despite optimal medical therapy, severe secondary mitral regurgitation, left ventricular ejection fraction (LVEF) between 15 percent and 40 percent, and at least one episode of hospitalization for HF within 12 months. They were randomized to undergo percutaneous mitral-valve repair with the MitraClip device plus medical therapy, or medical therapy alone. [N Engl J Med 2018, doi: 10.1056/NEJMoa1805374]
Among patients who were randomized to undergo percutaneous mitral-valve repair with MitraClip, 95.8 percent had the device successfully implanted. At the time of discharge from hospital, 95.1 percent of patients had a reduction in mitral regurgitation severity of at least one grade, 91.9 percent had reduction of mitral regurgitation severity to grade 2+ or lower, and 75.6 percent had reduction to grade 0+ to 1+. The procedure was generally safe.
In the intent-to-treat population, the composite primary endpoint of all-cause mortality or unplanned rehospitalization for HF at 12 months failed to demonstrate a significant difference favouring percutaneous mitral-valve repair plus medical therapy vs medical therapy alone (54.6 percent vs 51.3 percent; odds ratio, 1.16; 95 percent confidence interval [CI], 0.73 to 1.84; p=0.53). The rate of all-cause death was 24.3 percent in patients receiving percutaneous mitral-valve repair plus medical therapy vs 22.4 percent in those receiving medical therapy alone (p=0.66), while the rate of HF rehospitalization was 48.7 percent vs 47.4 percent (p=0.47). Similar findings were noted in the per-protocol analysis.
“The results were also similar across all prespecified subgroups, including patients with LVEF <30 percent vs ≥30 percent, as well as those with mitral regurgitant orifice <30 mm2 vs 30-40 mm2 vs >40 mm2,” added Obadia.
Prospective registry studies suggest that percutaneous mitral-valve repair can reduce symptoms and improve functional capacity and quality of life in patients with secondary mitral regurgitation. However, it has remained uncertain whether adding percutaneous mitral-valve repair to medical treatment has a beneficial effect on hard clinical outcomes.
“The MITRA-FR study showed that percutaneous correction of secondary mitral regurgitation was safe and effective, but failed to translate into improved outcomes,” concluded Obadia. “This suggests that the poor clinical outcomes in this patient population is more due to the underlying cardiomyopathy than mitral regurgitation. Mitral regurgitation is probably just a marker of severity.”