Low-flow aortic stenosis and preserved left ventricular ejection fraction.
Previously, aortic valve stenosis (AS) etiology was usually congenital or due to rheumatic disease. However, the most frequent cause is now degenerative AS, which is often part of a continuum including increased rigidity of the aorta due to atherosclerosis and left ventricular dysfunction due to coronary artery disease. This article highlights newer approaches to quantify AS taking into account the inter-relation between the different components (valvular, vascular, and ventricular) affecting clinical outcome in these patients. Emphasis is given to a more comprehensive evaluation of AS severity going beyond classical measurements and including indices such as 1) the energy loss index to quantify the valvular obstruction net of pressure recovery; 2) systemic arterial compliance to quantify vascular load; and 3) valvular-arterial impedance to assess the global (valvular + vascular) increase in afterload. Routine use of these indices, easily measured by Doppler echocardiography, should improve clinical management of AS patients.