Abstract
Localized ventricular septal hypertrophy, also known as idiopathic hypertrophic subaortic stenosis or idiopathic hypertrophic subaortic septal obstruction (IHSS), can create severe ventricular outflow obstruction. This often results in a high sub-aortic pressure gradient with potentially lethal symptoms. In 1960, Braunwald described the hemodynamic characteristics of IHSS, and thereafter, Morrow developed a trans-aortic approach to resect a large part of the ventricular septum, enlarging the outflow tract. The Morrow operation has remained the gold standard for surgically treating this pathology. However, in patients with a small aortic annulus, a severely hypertrophied septum, and a long anterior mitral leaflet, the trans-aortic approach may be more difficult, resulting in an inadequate resection and/or systolic anterior leaflet motion. The latter usually increases the obstruction and can cause mitral regurgitation. Herein, we describe a minimally invasive trans-left atrial robotic approach to treat IHSS. First, the anterior mitral leaflet is incised radially to reveal the aortic outflow tract and ventricular septum, which are located posteriorly. Thereafter, a deep "block" of septum is excised, beginning at the right valve cusp nadir and continued counterclockwise toward the left fibrous trigone. This excision is extended to the anterior papillary muscle base, where any septal connections must be divided. Subsequently, the anterior leaflet is re-suspended and the repair is completed with a flexible annuloplasty band. If necessary, the anterior leaflet can be augmented with a pericardial patch. The "wristed" robotic instruments and magnified 3-D vision definitely facilitate an adequate septal resection and anterior papillary muscle mobilization. Moreover, it is possible that this fine control helps to reduce complications, such as heart block or a ventricular septal defect.