Impact of pressure recovery on echocardiographic assessment of asymptomatic aortic stenosis: a SEAS substudy

Abstract

Objectives: The aim of this analysis was to assess the diagnostic importance of pressure recovery in evaluation of aortic stenosis (AS) severity.

Background: Although pressure recovery has previously been demonstrated to be particularly important in assessment of AS severity in groups of patients with moderate AS or small aortic roots, it has never been evaluated in a large clinical patient cohort.

Methods: Data from 1,563 patients in the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study was used. Inner aortic diameter was measured at annulus, sinus, sinotubular junction, and supracoronary level. Aortic valve area index (AVAI) was calculated by continuity equation and pressure recovery and pressure recovery adjusted AVAI (energy loss index [ELI]), by validated equations. Primarily, sinotubular junction diameter was used to calculate pressure recovery and ELI, but pressure recovery and ELI calculated at different aortic root levels were compared. Severe AS was identified as AVAI and ELI < or =0.6 cm(2)/m(2). Patients were grouped into tertiles of peak transaortic velocity.

Results: Pressure recovery increased with increasing peak transaortic velocity. Overestimation of AS severity by unadjusted AVAI was largest in the lowest tertile and if pressure recovery was assessed at the sinotubular junction. In multivariate analysis, a larger difference between AVAI and ELI was associated with lower peak transaortic velocity (beta = 0.35) independent of higher left ventricular ejection fraction (beta = -0.049), male sex (beta = -0.075), younger age (beta = 0.093), and smaller aortic sinus diameter (beta = 0.233) (multiple R(2) = 0.18, p < 0.001). Overall, 47.5% of patients classified as having severe AS by AVAI were reclassified to nonsevere AS when pressure recovery was taken into account.

Conclusions: For accurate assessment of AS severity, pressure recovery adjustment of AVA must be routinely performed. Estimation of pressure recovery at the sinotubular junction is suggested.