SESAME technique: septal scoring along the midline endocardium.

Background: The management of interventricular septal hypertrophy is an area of rapidly increasing interest, spurred by continued challenges with transcatheter mitral valve replacement (TMVR) and the management of obstructive hypertrophic cardiomyopathy (oHCM).

Aims: We sought to evaluate the reproducibility of septal scoring along the midline endocardium (SESAME), a novel transcatheter intervention designed to replicate surgical myotomy.

Methods: This single-centre, retrospective review included all patients who underwent the SESAME procedure at the University of Washington from January 2022 to September 2024.

Results: A total of 54 consecutive patients underwent SESAME at our institution: 47 prior to TMVR, 6 for oHCM, and 1 for a subaortic membrane. Technical success was achieved in 100% of patients. In pre-TMVR patients, the median neo-left ventricular outflow tract (LVOT) and the median skirt neo-LVOT areas gained were 146 (first quartile [Q1]: 76.5, third quartile [Q3]: 286.3) mm² and 54 (Q1: 32.8, Q3: 100.2) mm², respectively. In the oHCM population, invasive resting and provocable LVOT gradients immediately decreased from 59 (Q1: 32, Q3: 99) mmHg to 10 (Q1: 5, Q3: 19) mmHg and from 121 (Q1: 53, Q3: 205) mmHg to 34 (Q1: 16, Q3: 56) mmHg, respectively. The median echo gradients decreased from 62 (Q1: 53, Q3: 64) mmHg at baseline to 6 (Q1: 6, Q3: 8) mmHg at 30 days. Among the pre-TMVR population, there were 2 procedural deaths from free-wall rupture early in the experience and 3 restrictive ventricular septal defects that did not require intervention. Three patients (5.5%) required a pacemaker. Procedural complications significantly decreased after the first 10 cases in 2022 (p<0.01).

Conclusions: Our study corroborates the feasibility and efficacy of SESAME for prohibitive surgical risk patients needing septal reduction therapy prior to TMVR or for treatment of oHCM or a subaortic membrane.