Valvuloarterial impedance (Zva): Global left ventricular afterload in aortic stenosis

Valvuloarterial impedance (Zva): Global left ventricular afterload in aortic stenosis Valvuloarterial impedance (Zva) is an echocardiographic measure of global left ventricular afterload in aortic stenosis [1]. It accounts for the effect of both aortic stenosis and systemic arterial compliance. Zva (mmHg/ml/m2) = (systolic blood pressure + mean transvalvular pressure gradient)/stroke volume index Here the systemic arterial pressure and mean transvalvar gradient are taken beyond the region of pressure recovery in aortic stenosis. This mean transvalvar gradient has been called the net mean gradient. In a study of 208 patients with at least moderate aortic stenosis, Briand M and colleagues found that Zva was the only hemodynamic variable independently associated with left ventricular dysfunction [1]. Ito H et al showed that post operative Zva was significantly associated with regression of left ventricular mass after aortic valve replacement [2]. Left ventricular global afterload has to be maintained low for enhancing reverse remodelling of the left ventricle. This would include optimal control of blood pressure in a hypertensive. It has been documented earlier that in patients with mild – moderate aortic stenosis, hypertension was associated with more abnormal left ventricular structure and increased adverse cardiovascular events [3]. Patients with moderate aortic stenosis and concomitant hypertension may have a global hemodynamic load equivalent to or more than ...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: Echocardiography Aortic stenosis aortic stenosis with hypertension Global left ventricular afterload Global left ventricular afterload in aortic stenosis mean transvalvar gradient net mean gradient pressure recovery in aortic stenosis Valv Source Type: blogs