Background:Left ventricular outflow tract obstruction complicates hypertrophic cardiomyopathy and transcatheter mitral valve replacement. Septal reduction therapies including surgical myectomy and alcohol septal ablation are limited by surgical morbidity or coronary anatomy and high pacemaker rates, respectively. We developed a novel transcatheter procedure, mimicking surgical myotomy, called Septal Scoring Along the Midline Endocardium (SESAME).Methods:SESAME was performed in 5 naive pigs and 5 pigs with percutaneous aortic banding–induced left ventricular hypertrophy. Fluoroscopy and intracardiac echocardiography guided the procedures. Coronary guiding catheters and guidewires were used to mechanically enter the basal interventricular septum. Imparting a tip bend to the guidewire enabled intramyocardial navigation with multiple df. The guidewire trajectory determined the geometry of SESAME myotomy. The myocardium was lacerated using transcatheter electrosurgery. Cardiac function and tissue characteristics were assessed by cardiac magnetic resonance at baseline, postprocedure, and at 7- or 30-day follow-up.Results:SESAME myotomy along the intended trajectory was achieved in all animals. The myocardium splayed after laceration, increasing left ventricular outflow tract area (753 to 854 mm², P=0.008). Two naive pigs developed ventricular septal defects due to excessively deep lacerations in thin baseline septa. No hypertrophy model pig, with increased septal thickness and left ventricular mass compared with naive pigs, developed ventricular septal defects. One animal developed left axis deviation on ECG but no higher conduction block was seen in any animal. Coronary artery branches were intact on angiography with no infarction on cardiac magnetic resonance late gadolinium imaging. Cardiac magnetic resonance chamber volumes, function, flow, and global strain were preserved. No myocardial edema was evident on cardiac magnetic resonance T1 mapping.Conclusions:This preclinical study demonstrated feasibility of SESAME, a novel transcatheter myotomy to relieve left ventricular outflow tract obstruction. This percutaneous procedure using available devices, with a safe surgical precedent, is readily translatable into patients.

中文翻译：

---

经导管肌切开术缓解左心室流出道梗阻：动物中线心内膜手术中的隔膜评分

背景：左心室流出道梗阻使肥厚型心肌病和经导管二尖瓣置换术复杂化。包括手术肌切除术和酒精间隔消融术在内的间隔减少疗法分别受到手术发病率或冠状动脉解剖结构和高起搏器使用率的限制。我们开发了一种模仿外科肌切开术的新型经导管手术，称为心内膜中线隔膜评分 (SESAME)。方法：对 5 头幼猪和 5 头经皮主动脉环扎诱导的左心室肥厚的猪进行 SESAME。荧光检查和心内超声心动图指导手术。冠状动脉引导导管和导丝用于机械进入基底室间隔。向导丝施加尖端弯曲可以实现心肌内导航与多个DF。导丝轨迹决定了 SESAME 肌切开术的几何形状。使用经导管电外科手术撕裂心肌。在基线、术后和随访 7 天或 30 天时通过心脏磁共振评估心脏功能和组织特征。结果：所有动物均实现了沿预期轨迹的 SESAME 肌切开术。撕裂后心肌张开，左心室流出道面积增加（753 至 854 mm ²，P=0.008)。由于薄基线隔膜中的过深撕裂，两只幼稚的猪出现了室间隔缺损。与幼稚猪相比，室间隔厚度和左心室质量增加的肥大模型猪均未发生室间隔缺损。一只动物在 ECG 上出现电轴左偏，但在任何动物中都没有观察到更高的传导阻滞。冠状动脉分支在血管造影上完好无损，在心脏磁共振晚期钆成像上没有梗塞。保留了心脏磁共振腔容积、功能、流量和整体应变。心脏磁共振 T1 映射没有明显的心肌水肿。结论：这项临床前研究证明了 SESAME 的可行性，SESAME 是一种新型经导管肌切开术，可缓解左心室流出道阻塞。