Proximal Isovelocity Surface Area (PISA) in the Evaluation of Fixed Membranous Subaortic Stenosis

Abstract

The evaluation of the severity of subaortic stenosis is usually expressed by the magnitude of the subvalvular gradient. Calculation of the membrane orifice area noninvasively is difficult by the standard means. We present a patient in whom the area was calculated using the proximal isovelocity surface area (PISA) method. This method should have clinical applicability because it is not flow dependent and can be used in patients with normal, reduced, or increased stroke volume.

Geometry of the left ventricular outflow tract in fixed subaortic stenosis and intact ventricular septum: An echocardiographic study in children and adults

“…Trans-thoracic and transesophageal echocardiography are useful in identifying LVOT abnormalities in subvalvar aortic stenosis. 9,10,[19][20][21][22] The progression of both the severity of obstruction and the degree of associated aortic regurgitation can be assessed by outflow tract Doppler pressure gradient. 19 There was a significant difference between preoperative and postoperative values in aortoseptal angle (Figure 3, A, B) and LVOT width in patients up to 10 years of age.…”

Subaortic Stenosis Missed by Invasive Hemodynamic Assessment

“…However, we report on the first case of subaortic stenosis that was missed with invasive hemodynamic assessment. Doppler echocardiography is used in subaortic stenosis to noninvasively measure the transaortic velocity, and the pressure gradient, as well as estimating the orifice area using the proximal isovelocity surface area method 13 . The pressure gradient measured by Doppler has been closely correlated with the pressure gradient on invasive measurement in multiple studies, but the latter is still considered the gold standard 14 .…”

Thoughts about fixed subaortic stenosis in man and dog

“…Both transthoracic and transesophageal echocardiographic imaging ( Figs 8-10) has facilitated the appreciation of those morphologies. 51,53,[74][75][76]121,125,126 Without resorting to postoperative cardiac catheterization, intra-operative and postoperative studies permit ongoing assessment of the adequacy of relief of the obstruction, and demonstrate any inadvertant perforation of the ventricular septum, reveal any mitral annular aneurysm, or exclude iatrogenic mitral regurgitation.…”