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Transcatheter Myotomy to Reduce Left Ventricular Outflow Obstruction
Adam B Greenbaum1, Hiroki A Ueyama2, Patrick T Gleason2
1Structural Heart and Valve Center, Emory University Hospital, Atlanta, Georgia, USA. Electronic address: https://twitter.com/AdamGreenbaumMD.
Insights
A novel transcatheter electrosurgical procedure, septal scoring along midline endocardium (SESAME), effectively treated left ventricular outflow tract (LVOT) obstruction in hypertrophic cardiomyopathy and facilitated valve replacement procedures with high survival rates.
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.
Background:
Left ventricular outflow tract (LVOT) obstruction is a source of morbidity in hypertrophic cardiomyopathy (HCM) and a life-threatening complication of transcatheter mitral valve replacement (TMVR) and transcatheter aortic valve replacement (TAVR). Available surgical and transcatheter approaches are limited by high surgical risk, unsuitable septal perforators, and heart block requiring permanent pacemakers.
Objectives:
The authors report the initial experience of a novel transcatheter electrosurgical procedure developed to mimic surgical myotomy.
Methods:
We used septal scoring along midline endocardium (SESAME) to treat patients, on a compassionate basis, with symptomatic LVOT obstruction or to create space to facilitate TMVR or TAVR.
Results:
In this single-center retrospective study between 2021 and 2023, 76 patients underwent SESAME. In total, 11 (14%) had classic HCM, and the remainder underwent SESAME to facilitate TMVR or TAVR. All had technically successful SESAME myocardial laceration. Measures to predict post-TMVR LVOT significantly improved (neo-LVOT 42 mm2 [Q1-Q3: 7-117 mm2] to 170 mm2 [Q1-Q3: 95-265 mm2]; P < 0.001; skirt-neo-LVOT 169 mm2 [Q1-Q3: 153-193 mm2] to 214 mm2 [Q1-Q3: 180-262 mm2]; P < 0.001). Among patients with HCM, SESAME significantly decreased invasive LVOT gradients (resting: 54 mm Hg [Q1-Q3: 40-70 mm Hg] to 29 mm Hg [Q1-Q3: 12-36 mm Hg]; P = 0.023; provoked 146 mm Hg [Q1-Q3: 100-180 mm Hg] to 85 mm Hg [Q1-Q3: 40-120 mm Hg]; P = 0.076). A total of 74 (97.4%) survived the procedure. Five experienced 3 of 76 (3.9%) iatrogenic ventricular septal defects that did not require repair and 3 of 76 (3.9%) ventricular free wall perforations. Neither occurred in patients treated for HCM. Permanent pacemakers were required in 4 of 76 (5.3%), including 2 after concomitant TAVR. Lacerations were stable and did not propagate after SESAME (remaining septum: 5.9 ± 3.3 mm to 6.1 ± 3.2 mm; P = 0.8).
Conclusions:
With further experience, SESAME may benefit patients requiring septal reduction therapy for obstructive hypertrophic cardiomyopathy as well as those with LVOT obstruction after heart valve replacement, and/or can help facilitate transcatheter valve implantation.
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