Rate of Change in Aortic Valve Area During a Cardiac Cycle Can Predict the Rate of Hemodynamic Progression of Aortic Stenosis

Abstract

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 Ն0.9 cm 2 , annual echocardiographic data were obtained prospectively (mean follow-up 2.8Ϯ1.3 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 Ն0.2 cm 2 /y) or slow (Ͻ0.2 cm 2 /y). Rapid progression was significantly associated with an AVA ratio of Ն1.25 (Pϭ0.004, risk ratio 3.1, 95% CI 1.2 to 7.9). The sensitivity, specificity, and positive predictive value of AVA ratio of Ն1.25 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 Ն1.25 (Ϫ4Ϯ7% versus ϩ2Ϯ7%, PϽ0.001). 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.

Towards computational modelling of aortic stenosis

“…These time-transients are currently not considered clinically, since the assessment criteria are integrated over time (unlike the criteria used in this study). Some preliminary studies have been presented to investigate the value of time transients for AS severity assessment [28] and three-dimensional modelling would be highly suitable to complement that type of research. Finally, some issues regarding the existing assessment criteria identified in clinical studies, such as the flow dependence and pressure recovery were discussed.…”

“…Note that cross-sectional areas, A LVOT and EOA dop are considered constant through systole. Time-transients have received little attention in the literature, although a relation between AS progression and variations of EOA dop in time might exist [28]. Although Equations (1) and (2) were expected to provide the same values, this was not observed in practice [2].…”

Aortic valve replacement in elderly patients: what are the limits?

“…Referral should not be delayed until the patient is in congestive failure and has organ dysfunction [16][17][18][19][20][21]. The new minimally invasive approaches are especially attractive to the elderly age group to minimize surgical trauma and improve outcomes.…”

Valvular Aortic Stenosis

“…However, measurement of the dynamic change in AVA is challenging because it requires precise measurements at two flow rates, and the observed changes are close to the limits of measurement variability. Valve flexibility also can be estimated from the variability in valve opening during a single systolic ejection period (14). Again, although conceptually sound, clinical utility is problematic due to measurement variability.…”