Transcatheter Myotomy to Reduce Left Ventricular Outflow Obstruction

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Cardiac Surgery

Background:

• Left ventricular outflow tract (LVOT) obstruction is a significant complication in hypertrophic cardiomyopathy (HCM) and following transcatheter aortic valve replacement (TAVR) and transcatheter mitral valve replacement (TMVR).
• Current treatment options are limited by high risks and complications such as heart block requiring permanent pacemakers.

Purpose of the Study:

• To evaluate the initial experience of a novel transcatheter electrosurgical technique, septal scoring along midline endocardium (SESAME), designed to mimic surgical myotomy.
• To assess the safety and efficacy of SESAME in patients with symptomatic LVOT obstruction or those requiring facilitation of TMVR/TAVR.

Main Methods:

• A single-center retrospective study of 76 patients undergoing SESAME between 2021 and 2023.
• SESAME was used to treat 11 patients with HCM and 65 patients to facilitate TMVR or TAVR.
• Myocardial laceration was performed using SESAME, and outcomes including LVOT dimensions, gradients, and procedural complications were analyzed.

Main Results:

• All SESAME procedures were technically successful, with significant improvements in LVOT dimensions for patients undergoing valve replacement.
• In HCM patients, SESAME led to a significant reduction in resting LVOT gradients.
• The procedure demonstrated a high survival rate (97.4%), with low rates of serious complications like ventricular septal defects and free wall perforations. Permanent pacemaker implantation was infrequent.

Conclusions:

• SESAME is a promising transcatheter technique for managing LVOT obstruction in both HCM and post-valve replacement scenarios.
• The procedure can effectively reduce LVOT gradients and facilitate transcatheter valve implantation.
• Further experience with SESAME may establish it as a valuable therapeutic option for specific patient populations.