心室中部および心尖部肥大型心筋症の外科的治療

The diverse phenotypes of hypertrophic cardiomyopathy (HCM) - including subaortic, midventricular, and apical hypertrophy - present distinct surgical challenges. While transaortic septal myectomy remains the standard approach for relieving subaortic obstruction, it may not offer adequate exposure to the midventricle and apex, limiting its effectiveness in patients with midventricular obstruction (MVO), apical HCM, or complex long-segment septal hypertrophy. To address these potential limitations, surgeons at the Mayo Clinic have utilized a transapical incision for myectomy at the mid and distal portions of the left ventricle. Over the past three decades, transapical myectomy has proved to be a safe and effective adjunct or alternative surgical strategy. This approach offers direct visualization of the hypertrophied midventricular septum and papillary muscles, allowing for complete resection and relief of intracavitary gradients in MVO. In patients with apical HCM and diastolic heart failure, apical myectomy increases left ventricular end-diastolic volume and stroke volume, improving symptoms and exercise capacity. The transapical route also facilitates repair of apical aneurysms when present. Procedural morbidity and mortality are low, and we have observed durable symptomatic relief and favorable long-term survival. In select patients with advanced heart failure symptoms who are not candidates for, or wish to defer, heart transplantation, apical myectomy represents a viable and effective surgical alternative. This review outlines the clinical indications, surgical technique, and outcomes of transapical myectomy, underscoring its role in the contemporary surgical management of complex HCM phenotypes.