Invasive Management of Hypertrophic Cardiomyopathy With Clinically Important Obstruction: Surgical Myectomy Is Superior, but Only When Accessible

Abstract

For patients with hypertrophic cardiomyopathy (HCM), a thickened intraventricular septum and systolic anterior motion of the mitral valve (SAM) can contribute to significant left ventricular outflow tract obstruction (LVOTO), mitral regurgitation, and debilitating symptoms. Current guidelines recommend septal reduction therapy through alcohol septal ablation or surgical septal myectomy for patients whose symptoms persist despite medical therapy. Although alcohol septal ablation is a less invasive treatment option, it is not suitable for patients with septal perforator branch anatomy that is not compatible with the procedure, those with midcavitary obstruction, and patients in whom the mechanism of LVOTO is primarily related to SAM. Septal ablation also has a notably higher rate of atrioventricular block requiring permanent pacemaker insertion, and the need for reintervention has been reported to be 15% or more. In contrast, septal myectomy offers direct visualisation and can address thickened septum and mitral valve (MV) anomalies. It can be used to treat a wider variety of anatomies, with lower rates of reoperation. Aside from the more invasive nature of the procedure, a major limitation of septal myectomy, however, is access, because relatively few surgeons specialise in the procedure. This is important because there is a significant correlation between procedural volumes and outcomes. Patients should be evaluated by a multidisciplinary heart team to ensure that they are aware of all treatment options. In this review, we explore the 2 methods of septal reduction therapy and highlight the need for further training of septal myectomy surgeons to ensure access to optimal septal reduction therapies for Canadian patients with HCM.