Abstract 16547: Preserved Ejection Fraction With Low Gradient and Low Flow Aortic Stenosis: A True Entity or Misclassification? Can Left Ventricular Remodeling Differences Improve Characterization of This Group?
Background: There is uncertainty in defining patients (pts) with preserved ejection fraction (EF) and low gradient, low flow severe aortic stenosis (PLGF AS). Studies propose that PLGF AS pts have maladaptive hypertrophy to pressure load resulting in low forward stroke volume. Others suggest that most PLGF AS pts are misclassified and should be in the moderate AS spectrum. We hypothesized that PLGF AS pts have differential LV remodeling compared to pts with normal flow AS which may help to distinguish this group.
Methods: We searched our echo database for pts with severe AS (aortic valve area (AVA) <1.0 cm2) and EF >55% over a 1 year period. PLGF AS pts (AVA <1.0 cm2, mean gradient (MG) <40 mmHg, stroke volume index (SVi) <35 mL/m2) were compared to pts (Group 2; n=56) with AVA <1.0 cm2, MG <40 mmHg but normal flow (SVI >35 mL/m2) and to pts (Group 3; n=51) with moderate AS (AVA 1.0 - 1.3 cm2). AVA (continuity), end-diastolic (EDVi) and end-systolic (ESVi) indexed volumes, SVi (LVOT area x velocity), and relative wall thickness (RWT = 2 x posterior wall thickness)/end-diastolic dimension) which is an index of LV hypertrophy relative to LV size were measured by 2D echo. Mortality was assessed by the Social Security death index.
Results: Among 183 pts, 23 (13%) were PLGF AS pts. They had the lowest AVA (0.77 vs. 0.88 vs. 1.17 cm2, p<0.001) with an intermediate MG (23 vs. 31 vs. 19 mmHg, p<0.001) compared to groups 2 and 3, respectively (Fig). PLGF AS pts had lower EDVi (44 vs. 55 vs. 54 mL/m2, p<0.001), ESVi (13 vs. 16 vs. 16 mL/m2, p=0.03), and highest RWT (53 vs. 48 vs. 47%, p=0.008; c-statistic = 0.73). There was no difference in EDVi, ESVi, and RWT between groups 2 and 3. Survival was similar (follow up 2.7 yrs) among the groups (p=0.4).
Conclusion: PLGF AS represents a minority of pts with severe AS. PLGF AS pts have LV remodeling features consistent with a maladaptive hypertrophy response to pressure load. In contrast, pts with similar degree of AS but normal SVi have LV remodeling features similar to moderate AS.
- © 2011 by American Heart Association, Inc.