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Transcatheter Myotomy to Reduce LVOT Obstruction
Quick Takes
- SESAME (SEptal Scoring Along Midline Endocardium) mimics surgical myotomy with the aim to score the midline septal myocardium, producing septal myocardial splay and reducing the hypertrophic bulge.
- The current study reports on an early pilot experience with the SESAME technique among patients with HCM and LVOT obstruction or to enable TMVR or TAVR. Results suggest reduction in LVOT gradients with symptomatic improvement, especially among the HCM cohort.
- Procedural complications included ventricular septal defect (3.9%), free wall rupture (3.9%), and need for permanent pacemaker (5.3%).
Study Questions:
How safe and effective is the novel transcatheter electrosurgical procedure SESAME (SEptal Scoring Along Midline Endocardium) to reduce left ventricular outflow tract (LVOT) obstruction?
Methods:
SESAME was used to treat patients, on a compassionate basis, with symptomatic LVOT obstruction or to create space to facilitate transcatheter mitral valve replacement (TMVR) or transcatheter aortic valve replacement (TAVR).
Results:
In this single-center retrospective study between 2021–2023, 76 patients underwent SESAME. Eleven (14%) had classic hypertrophic cardiomyopathy (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 [7-117] to 170 [95-265] mm2, p < 0.001; skirt-neo-LVOT 169 [153-193] to 214 [180-262] mm2, p < 0.001). Among patients with HCM, SESAME significantly decreased invasive LVOT gradients (resting: 54 [40-70] to 29 [12-36] mm Hg, p = 0.023; provoked 146 [100-180] to 85 [40-120] mm Hg, p = 0.076). Seventy-four (97.4%) survived the procedure. Five suffered 3/76 (3.9%) iatrogenic ventricular septal defects that did not require repair, and 3/76 (3.9%) ventricular free wall perforations. Neither occurred in patients treated for HCM. Permanent pacemakers were required in 4/76 (5.3%), including two 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 HCM, with LVOT obstruction after heart valve replacement, and/or to prepare for transcatheter valve implantation.
Perspective:
SESAME mimics surgical myotomy with the aim to score the midline septal myocardium, producing septal myocardial splay and reducing the hypertrophic bulge. The current study reports on early experience with this novel transcatheter technique among patients with HCM and LVOT obstruction or to enable TMVR or TAVR. Results suggest reduction in LVOT gradients with symptomatic improvement, especially among the HCM cohort. Overall rates of complications were low; ventricular septal defect (3.9%), free wall rupture (3.9%), need for permanent pacemaker (5.3%). The authors appropriately caution about the technical challenges related to the procedure and continued need for further study. In its current form, the clinical applicability, safety, and long-term benefits of SESAME remain unknown.
Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention
Keywords: Hypertrophic Cardiomyopathy, Myotomy, Transcatheter Aortic Valve Replacement
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