Abstract 11001: Comparing the Effects of Low-Flow Aortic Stenosis with Preserved Ejection Fraction Versus Normal-Flow Aortic Stenosis on Left Ventricular Diastolic Function and Left Atrial Volumes
Background: Paradoxical low-flow (LF) significant aortic stenosis (AS) despite preserved left ventricular ejection fraction (LVEF) is associated with reduced survival compared to normal-flow (NF) AS. We compared echo parameters including tissue Doppler indices (TDI) and left atrial volume (LAV) as diastolic dysfunction may contribute to poorer outcomes.
Methods: In 274 pts with moderate-to-severe AS (aortic valve area index (AVAI)<1 cm2/m2) and preserved LVEF (≥ 50%), conventional parameters, mitral annular TDI parameters, indexed LAVs (area-length), valvulo-arterial impedance (Zva) and systemic arterial compliance (SAC) were measured or derived. These were compared between LF (defined as stroke volume index ≤ 35 ml/m2) and NF pts (n=221). We excluded pts with mitral annular calcification, atrial fibrillation and other valvular disease (≥grade II). Between-group comparisons adjusted for AVAI and Pearson correlates were performed.
Results: LF pts had significantly smaller AVAI (0.47 ± 0.16 vs 0.58 ± 0.16 cm2/m2, P<0.001), higher Zva, lower LVEF (62±7 vs 66±5%, P=0.005), LV mass index (MI), end-diastolic volume (EDV) and SAC (table). The LF group had a trend towards higher LV E/E' ratios and lower TDI velocities (table). Indexed LAVs (LAVI) were increased in both but were lower in the LF group (table). However, LAVI correlated better with indices of diastolic dysfunction in the LF compared to NF group (E/A, rho=0.53, P<0.001 vs rho=0.15, P=0.024 and E/E' rho=0.50 vs 0.27, Ps<0.001).
Conclusions: LF pts have smaller left heart chamber sizes and mass compared to NF group. LAVI is increased in both LF and NF. Though NF pts have larger LAVI, this may not be contributed by worse LV diastolic dysfunction. Despite significantly higher LV afterload burden as reflected by Zva, diastolic function in LF pts is only mildly reduced compared to NF pts.
- © 2011 by American Heart Association, Inc.