First-in-human data for a novel transcatheter electrosurgical procedure developed to mimic surgical myotomy suggest it may provide benefit to patients requiring septal reduction therapy for obstructive hypertrophic cardiomyopathy (HCM). Findings from the early experience of SESAME – a catheter-based non-surgical myotomy that can relieve left ventricular outflow tract (LVOT) obstruction in HCM and create space to allow transcatheter mitral valve replacement (TMVR) – were presented Sunday at Cardiovascular Revascularization Technologies (CRT) 2024 in Washington, D.C., published simultaneously online in the Journal of the American College of Cardiology. Led by Vasilis Babaliaros, MD, from Emory University Hospital, Atlanta, the research team noted that LVOT obstruction is a source of morbidity in HCM and a life-threatening complication of TMVR and transcatheter aortic valve replacement (TAVR). Speaking at CRT 2024, Babaliaros noted currently available surgical and transcatheter approaches are limited by high surgical risk, unsuitable septal perforators, and heart block requiring permanent pacemakers. “We developed a new transcatheter electrosurgical technique (SESAME) to fill an unmet clinical need in patients that required LVOT modification peri-transcatheter heart valve replacement and for treatment of symptomatic obstructive HCM on a compassionate basis,” he said. “Transcatheter myotomy using the SESAME technique was envisioned to mimic the benefits of surgical resection (geographic accuracy) combined with the minimal invasiveness of transcoronary alcohol septal ablation, but with a lower risk of iatrogenic complete heart block and tissue injury confined only to the intended anatomic target.” Study details The findings come from the very first human experiences with SESAME, applied immediately after completion of animal studies that showed the feasibility of intramyocardial navigation and electrosurgical myocardial laceration. The team used Septal Scoring Along the Midline Endocardium (SESAME) to treat patients, on a compassionate basis, with symptomatic LVOT obstruction or to create space to facilitate TMVR or TAVR. “In this single-center retrospective study between 2021-2023, 76 patients underwent SESAME,” said Babaliaros. “Eleven (14%) had classic HCM, and the remainder underwent SESAME to facilitate TMVR or TAVR.” All patients had technically successful SESAME myocardial laceration, he said, noting that measures to predict post-TMVR LVOT significantly improved (neo-LVOT 51±53 to 205±168mm2,p<0.001; skirt-neo-LVOT 169 to 236 mm2, p=0.009). Furthermore, among patients with HCM, SESAME significantly decreased invasive LVOT gradients (resting: 54 to 29 mmHg, p=0.023; provoked 146 to 85mmHg, p=0.076). Babaliaros added that 74 patients (97.4%) survived the procedure – noting that five suffered three (3.9%) iatrogenic ventricular septal defects that did not require repair and three (3.9%) ventricular free wall perforations. “Neither occurred in patients treated for HCM,” he said, noting that permanent pacemakers was required in four (5.3%), including two after concomitant TAVR, while lacerations were stable and did not propagate after SESAME (remaining septum: 5.9±3.3 mm to 6.3±3.4 mm, p=0.6). “With further experience, SESAME may benefit patients requiring septal reduction therapy for obstructive hypertrophic cardiomyopathy, with LVOT obstruction after heart valve replacement, and/or to prepare for transcatheter valve implantation,” concluded Babaliaros. Source: Greenbaum AB, Ueyama HA, Gleason PT, et al. Transcatheter Myotomy to Reduce Left Ventricular Outflow Obstruction. J Am Coll Cardiol. 2024 Mar 10 (Article in press) Photo Credit: Bailey Salimes/CRTonline.org Photo Caption: Vasilis Babaliaros, MD, presents early results of the SESAME procedure Sunday at CRT 2024 in Washington, D.C.