ABSTRACT
CLINICAL PRESENTATION Because of the physiology described above, symptoms and physical exam findings may appear with seemingly moderate individual valve lesions. The hemodynamic assessment is also modified by the presence of mixed valve disease. Pressure gradients across a stenotic aortic valve will be augmented by
the increased flow accompanying regurgitation. Thus, estimates of severity of stenosis based solely on pressure gradients must be avoided. In addition, calculation of valve area based on invasive hemodynamic data is unreliable and will likely overestimate AS, because Fick and thermodilution estimates of cardiac output measure net forward flow only (not total transvalvular flow). In cases of mixed AR and AS, quantitative echocardiographic estimates of valve area (AVA) and effective regurgitant orifice (ERO) are most accurate provided there is not accompanying mitral regurgitation (MR). If both the aortic and mitral valves are regurgitant, planimetry of the aortic valve during transesophageal echocardiography (TEE) is the preferred method of determining valve area. As an indirect measure of the primary hemodynamic burden, the size and thickness of the LV generally reflect the dominant valve lesion. A dilated LV suggests AR; a normal sized LV with concentric hypertrophy implies AS (149-154, Table 22).
