Percutaneous Mitral Valve Plication for Obstructive HCM
What is the potential effectiveness of percutaneous mitral valve plication as a therapy for patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM)?
Six patients (age 83 ± 8 years; five women), judged as not optimal candidates for septal myectomy, were referred for management of severe drug-refractory heart failure symptoms due to obstructive HCM (New York Heart Association [NYHA] class III). Each underwent percutaneous mitral valve leaflet plication to reduce systolic anterior motion (SAM) and mitral regurgitation (MR) using the transcatheter mitral clip system. Major adverse clinical events were defined as the occurrence of either stroke, myocardial infarction, major bleeding, or death, using Valve Academic Research Consortium 2 (VARC-2) criteria.
The procedure was completed in five patients with placement of a single clip at the A2-P2 segments of the mitral valve. One other patient experienced cardiac tamponade, leading to termination of the procedure. Among the five treated patients, percutaneous plication with the clip eliminated SAM and consequently decreased the intraoperative left ventricular outflow tract (LVOT) gradient (91 ± 44 mm Hg to 12 ± 6 mm Hg; p = 0.007), left atrial pressure (29 ± 11 mm Hg to 20 ± 8 mm Hg; p = 0.06), and MR grade (3.0 ± 0 vs. 0.8 ± 0.4; p = 0.0002) associated with improved cardiac output (in n = 4; 3.0 ± 0.6 L/min to 4.3 ± 1.2 L/min; p = 0.03). Over follow-up of 15 ± 4 months, symptom improvement to NYHA class I or II occurred in all patients. Follow-up echocardiography after 15 ± 4 months demonstrated continued absence of SAM and significant reduction in MR, although high systolic LVOT velocities (i.e., >4 m/s) were evident in three of the five treated patients.
The authors concluded that percutaneous mitral valve plication may be effective for symptom relief in obstructive HCM patients via reduction of SAM and MR.
This pilot study reports that percutaneous mitral valve plication with the mitral clip may possibly be effective for symptom relief in patients with obstructive HCM via reduction of SAM and MR. The experience with percutaneous mitral valve plication in obstructive HCM reported here is early and in only a small number of patients, with the appropriate selection of those who are likely to benefit from this treatment currently incompletely understood. While it is possible that 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, additional studies on the outcomes of this therapy in a larger population of patients with HCM are needed, including better understanding of the significance of persistent elevations of LVOT velocities in some patients.
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