Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis and Large Membranous Interventricular Septal Aneurysm

A 74-year-old woman with morbid obesity and symptomatic severe aortic valve stenosis (AS) who had been deemed ineligible for surgical aortic valve replacement was evaluated for transcatheter aortic valve implantation (TAVI). A computed tomographic angiogram (CTA) of the chest revealed a defect in the membranous interventricular septum below the aortic valve consistent with aneurysm (Fig. 1A). A transthoracic echocardiogram (TTE)—of suboptimal image quality because of the patient's morbid obesity—provided no useful details about the defect. A subsequent transesophageal echocardiogram revealed a large (1.15 × 2.26-cm) noncommunicating membranous interventricular septal aneurysm (IVSA) near the left ventricular outflow tract (Fig. 1B). As calculated from multiplanar reconstructed CTAs, the IVSA below the aortic valve annulus measured 9.7 × 10.7 mm in the cross-sectional view (Fig. 2A) and 14.1 mm in the coronal view (Fig. 2B). In the cross-sectional view, the aortic annulus had a minimum diameter of 24.1 mm, a maximum diameter of 34.9 mm, a mean diameter of 29.5 mm, an area of 654.0 mm2, and a perimeter of 93.0 mm. After 5% oversizing based on an aortic annular area of 619 mm2 derived from the multiplanar reconstructed CTAs, we chose to implant a 29-mm Edwards SAPIEN 3 valve (Edwards Lifesciences Corporation) at a 50:50 aortic-to-ventricular position using a transfemoral approach (Fig. 3). A TTE obtained 1 month after TAVI revealed a normal gradient across the aortic prosthetic valve and a trace of perivalvular aortic regurgitation.Membranous IVSA is a rare, isolated congenital heart defect. It is usually discovered incidentally in adults, and it is not necessarily associated with a ventricular septal defect.1 Paravalvular leak (PVL) is a potential complication in patients with a large IVSA and severe AS if the transcatheter heart valve (THV) skirt does not provide optimal coverage at the aortic annulus and if the valve is not implanted deeply enough. Although the results in this case were suboptimal because of the persistent flow through the THV skirt to the IVSA and the potential risk of rupture or infection of the IVSA, no current TAVI devices are designed to exclude IVSAs or suitable for doing so.Other possible complications of IVSA with severe AS include thrombosis and perforation after TAVI. Banga and colleagues2 reported successful implantation of an Edwards SAPIEN XT valve at the 80% supra-annular position in an 81-year-old man with severe AS and membranous IVSA. We think, however, that implanting a replacement valve at the 50% transannular position across the native aortic valve leaflet can achieve optimal results without causing significant paravalvular leak. Our case suggests that TAVI is safe and feasible in patients with congenital membranous IVSA associated with severe AS.