title: Discrete subaortic membranous stenosis--a case report.
abstract: Isolated subaortic stenosis is a rare type of cardiac anomaly which has been characterized as having two types: the discrete type, including membranous or fibromuscular, and the tunnel type. In the discrete type, a crescent-shaped, fibrous curtain is attached to the ventricular septum or completely encircles the left ventricular outflow tract and can be located anywhere from immediately below the aortic valve to 10 mm or more into the body of ventricle. A 22-year-old female presented at our hospital with a divided PDA, a murmur that was found by incident and progressive exertional dyspnea. Echocardiography revealed left ventricular hypertrophy, moderate aortic insufficiency, and severe aortic stenosis characterized by a thickened aortic valve and membranous type subaortic stenosis with a transmembranous high pressure gradient, 121 mmHg. An operation to replace the aortic valve and excise the membranous collar was performed with cardiopulmonary bypass support. The patient did well during the postoperative follow-up period. If the preoperative LVOT pressure gradient had been higher than 45 mmHg, the incidence of recurrent stenosis, progression of aortic regurgitation and the need for reoperation would have been higher. In order to prevent this from happening, we chose to replace the defective valve with a mechanical valve and enucleate the discrete lesion.
authors: Division of Cardiovascular Surgery, Kaohsiung Medical University Hospital, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
authors: H M
authors: HM
authors: Chen
authors: Y F
authors: YF
authors: Chen
authors: J C
authors: JC
authors: Hsieh
authors: T C
authors: TC
authors: Chen
authors: C C
authors: CC
authors: Lin
authors: Y S
authors: YS
authors: Hwang
mesh_terms: D000328:Adult; D001020:Aortic Stenosis, Subvalvular / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans