Dynamic Left Ventricular Outflow Obstruction Following Aortic Valve Replacement

A 74-year-old male underwent aortic valve replacement (AVR) with a 21-mm Carpentier-Edwards Perimount aortic bioprosthesis (Ed-wards LifeSciences, Irvine, CA, USA) for symp-tomatic aortic valve stenosis (AS). Preopera-tively, transthoracic echocardiography (TTE) revealed left ventricular hypertrophy (LVH) with a sigmoid shaped ventricular septum.1,2 By transesophageal echocardiography (TEE) the planimetered aortic valve area was 0.85 cm2 (Fig. 1). Mitral chords appeared to be some-what elongated or “redundant, ” with noted sys-tolic anterior motion of the mitral valve (SAM), but leaflets did not “touch ” the interventricu-lar septum nor cause a subaortic gradient (Fig. 2). However, because of the sigmoid septum and “redundant ” chords, a myectomy was performed at the time of AVR. Histological evaluation of the myectomy specimen revealed myocardial hypertrophy, but myocyte disarray that is usu-ally noted with hypertrophic cardiomyopathy (HCM), was not present. Within 36 hours after surgery, the patient was noted to have a Grade III systolic mur-mur along the left sternal border as well as th