Rate of change in aortic valve area during a cardiac cycle can predict the rate of hemodynamic progression of aortic stenosis

Background - The ability to predict the rate of hemodynamic progression in an individual patient with valvular aortic stenosis has been elusive. The purpose of the present study was to evaluate whether the rate of change in aortic valve area (AVA) measured during the ejection phase of a cardiac cycle predicts the rate of hemodynamic progression in patients with asymptomatic aortic stenosis. Methods and Results - In 84 adults with initially asymptomatic aortic stenosis and a baseline AVA of ≥0.9 cm², annual echocardiographic data were obtained prospectively (mean follow-up 2.8 ± 1.3 years). With the initial echocardiogram, the ratio of AVA measured at mid- acceleration and mid-deceleration to the AVA at peak velocity was calculated. The primary outcome variable was the annual rate of change in AVA (rate of progression), with rate of progression classified as rapid (a reduction in AVA of ≥0.2 cm²/y) or slow (<0.2 cm²/y). Rapid progression was significantly associated with an AVA ratio of ≥1.25 (P=0.004, risk ratio 3.1, 95% CI 1.2 to 7.9). The sensitivity, specificity, and positive predictive value of AVA ratio of ≥ 1.25 for the prediction of rapid progression of valvar aortic stenosis was 64%, 72%, and 80% respectively. The decrease in ejection fraction measured from the initial to final echocardiogram was small but greater for patients with an AVA ratio of ≥1.25 (-4±7% versus +2±7%, P<0.001). Conclusions - A flow-dependent change in AVA can be measured during a routine transthoracic echocardiographic study. The rate of change in AVA is an additional measure of disease severity and may be used to predict an individual's risk for subsequent rapid disease progression.