肥大型心筋症の外科的治療

Hypertrophic cardiomyopathy (HCM) is a dynamic disease with a spectrum of clinical presentations ranging from incidental diagnosis to sudden cardiac death. Symptomatic patients are initially managed medically, and newer drugs are currently under investigation. Invasive therapy is needed for patients with intractable symptoms despite maximal medical therapy, and surgical myectomy is the gold standard treatment with better long-term survival.

Over three decades, more than 4000 patients underwent surgical myectomy at the Cleveland Clinic. We conducted a detailed analysis of patients who underwent surgery for HCM between 2005 and 2015. Within this study period, 1549 patients underwent surgical myectomy. Their mean pre-operative peak left ventricular outflow tract (LVOT) gradient was 63 ± 4.6 mmHg, and it reduced to 15 ± 8.9 mmHg after surgery. Mean aortic cross-clamp time was 28 ± 10 min for isolated septal myectomy, and the mean mass of muscle resected was 8.1 ± 3.7 g. Complications include new incidences of pacemaker insertion in 4.2% of the patients, iatrogenic ventricular septal defects in two patients, and the overall operative mortality was 0.38%. Mean hospital stay was 6 days, and the majority of the patients are in New York Heart Association (NYHA) class I in their post-operative follow-up.

Septal myectomy is a curative therapy for most patients of HCM who are symptomatic despite maximal medical management. Clear understanding of individual septal anatomy and mechanisms of LVOT obstruction are key to successful surgical outcomes. Septal myectomy can be done safely with excellent long-term results.