Percutaneous mitral valve plication may be effective as a primary therapy for symptom relief in patients with severely symptomatic, obstructive hypertrophic cardiomyopathy (HCM) through the reduction of systolic anterior motion (SAM) and mitral regurgitation, according to recent data published in the Journal of the American College of Cardiology.
There are currently very few therapeutic options for patients with severe heart failure due to HCM. However, the study researchers hypothesized that percutaneous mitral valve plication could reduce SAM and mitral regurgitation to provide an alternate strategy for heart failure patients.
“Plication of the mitral valve directly addresses the pathophysiology of dynamic LVOT [left ventricular outflow tract] obstruction by specifically targeting the mitral valve and SAM, as well as MR [mitral regurgitation],” the authors wrote.
“By directly plicating the valve leaflets and preventing SAM, the implanted mitral clip thereby prevents mitral-septal contact, increases LVOT area, normalizes LV pressure, relieves MR, and consequently alleviates heart failure symptoms.”
The study included 6 patients (average age 83 ± 8 years; 5 women) who were referred for management of severe, drug-refractory heart failure symptoms with obstructive HCM. The patients were not optimal candidates for septal myectomy, and were New York Heart Association (NYHA) functional class III.
Each patient underwent percutaneous mitral valve leaflet plication to reduce SAM and mitral regurgitation using the transcatheter mitral clip system. A single clip was placed at the A2-P2 segments of the mitral valve. The procedure was completed in 5 patients while 1 patient experienced cardiac tamponade, which led to termination of the procedure.
SAM of the mitral valve was eliminated in the 5 successfully treated patients. In addition, the clip implantation led to a reduction in the LVOT gradient from 91 ± 44 mm Hg to 12 ± 6 mm Hg (P=.007). There was also a reduction in left atrial pressure, from 29 ± 11 mm Hg to 20 ± 8 mm Hg (P=.06) and in mitral regurgitation grade (3 ± 0 vs 0.8 ± 0.4; P=.0002).
Researchers measured cardiac output in 4 patients, which increased from 3.0 ± 0.61 l/min to 4.3 ± 1.2 l/min (P=.03).
After a follow-up period of 15 ± 4 months, all patients demonstrated symptom improvement to NYHA functional class I or II. A follow-up echocardiography at the same time points demonstrated continued absence of SAM and reduction in mitral regurgitation.
There were high systolic LVOT velocities >4 m/s in 3 of the 5 treated patients, and the significance of these high velocities warrants further study. Researchers also note that further study should focus on outcomes of this therapy in a larger patient population.
“If deemed efficacious with further study, percutaneous mitral valve plication could represent a viable option for some patients with severely symptomatic, drug-refractory obstructive HCM, including those who are elderly or with unacceptable risk for surgical myectomy,” the authors concluded.
Sorajja P, Pedersen WA, Bae R, et al. First experience with percutaneous mitral valve plication as primary therapy for symptomatic obstructive hypertrophic cardiomyopathy. J Am Coll Cardiol. 2016;67(24):2811-2818. doi: 10.1016/j.jacc.2016.03.587.