Page 28 - Delaware Medical Journal - November 2015
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CASE REPORT
less commonly a muscular membrane 5 Subvalvar
AS is rarely encountered in newborns and infants and most consider it an It is postulated that an underlying abnormality in the LVOT architecture which in turn results in progressive 6 Many patients have associated aortic regurgitation (AR). The mechanism is thought to be
to trauma from the high velocity
jets caused by the subaortic lesion.7 Patients are typically asymptomatic and the lesion is often uncovered during auscultation of the heart and is generally performed for evaluation of a murmur. The characteristic murmur of the subaortic AS is a harsh systolic ejection
CONTRIBUTING AUTHORS
murmur heard best at the left sternal border. Unlike HCM, the intensity of
the murmur decreases with Valsalva maneuver. An early diastolic high (AR) is heard in some patients.
of the subaortic AS and helps assess
for presence of associated congenital lesions. Transoesophageal imaging
is usually needed to demonstrate the presence of the often subtle subaortic membrane, which is typically seen just proximal to the junction of the aortic
root arising from the membranous septum. The lesion, however, is often suspected on TTE when CW Doppler reveals high gradients and color Doppler indicative of turbulent and high subaortic
localization of the level of obstruction by detection of the site of maximum velocities. Absence of systolic anterior motion of the mitral valve, mitral regurgitation, and septal hypertrophy help differentiate subvalvular membrane from causes of dynamic LVOT obstruction such as HCM.
In contrast to valvar AS, subvalvar AS does not respond to balloon dilation
and treatment of choice is surgical resection of the membrane with or without myectomy. Main indications gradients of 50 mmHg or more in adults, regurgitation. The recurrence risk in the adult patient following initial surgical resection can be as high as
26 perceent.9,10
■ ARMIN BAREKATAIN, MD, MSc. is a Cardiology Fellow at Christiana Care Health System in Newark, Del.
■ ZAHER FANARI, MD is a Cardiology Fellow at Christiana Care Health System in Newark, Del.
■ SUMAYA HAMMAMI, MD, MPH is associated with the Department of Cardiology at Christiana Care Health System in Newark, Del. ■ WASIF QURESHI, MD Is a Cardiologist and practices with Delaware Cardiovascular Associates in Newark, Del.
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