• Justin H Booth, Roosevelt Bryant, Susan C Powers, Shuping Ge, E Dean McKenzie, Jeffrey S Heinle, Charles D Fraser, and David L S Morales.
• The University of Texas Medical School, Houston, United States of America.
• Cardiol Young. 2010 Jun 1;20(3):284-9.

BackgroundA discrete subaortic membrane cannot only cause left ventricular outflow tract obstruction, but can grow onto the aortic valve leaflets. The late finding of this encroachment is aortic valve insufficiency or stenosis. Echocardiography is used to follow the progression of outflow tract obstruction, but its ability to show subaortic membrane encroachment onto the aortic valve is unclear. The purpose of this study is to determine the sensitivity and specificity of echocardiography for diagnosing whether a discrete subaortic membrane involves the aortic valve.MethodsA pre-operative determination of aortic valve involvement by a discrete subaortic membrane was obtained by review of the official pre-operative echocardiogram reading and a retrospective blinded review of the pre-operative echocardiogram by an independent echocardiographer. These findings were compared to the intra-operative findings.ResultsA total of 48 consecutive patients underwent primary resection for isolated discrete subaortic membrane between October, 1995 and May, 2006. The pre-operative and blinded readings both predicted a statistically lower rate of aortic valve involvement - 35% in 11 of 31 patients and 31% in 10 of 31 patients, respectively - than found at surgery - 65% in 31 of 48 patients. The sensitivity and specificity of pre-operative echocardiography to diagnose aortic valve involvement is 35% and 76%. Overall survival was 100%. There were no strokes, re-operations for bleeding or wound infections, or need for a pacemaker.ConclusionEchocardiography is not sensitive in assessing whether a discrete subaortic membrane involves the aortic valve. Since the morbidity and mortality for discrete subaortic membrane resection is negligible, resection may be indicated at the time of diagnosis to minimise aortic valve impairment.

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