Abstract 11032: Impact of Obesity on Grading of Aortic Stenosis (a SEAS Substudy)
Background: We hypothesized that the disproportionate increase of body surface area (BSA) in obesity may lead to overestimation of aortic valve stenosis (AS) severity when the indexed valve area is used.
Methods: Baseline data from 1524 patients enrolled in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study were used to calculate aortic valve area (AVA) and pressure recovery adjusted AVA (energy loss [EL]) and their indexed values (AVAI and ELI). Obesity was defined as body mass index (BMI) ≥30 kg/m2.
Results: Peak aortic jet velocity, mean aortic gradient, AVA and EL did not differ between obese (n=321) and non-obese (n=1203) patient groups. A total of 225 patients had non-severe AS by AVA (>1.0 cm2), but severe AS by AVAI (<0.6 cm2/m2) (AVAI/AVA inconsistency), and 144 patients had non-severe AS by EL (>1.0 cm2), but severe by ELI (<0.6 cm2/m2) (ELI/EL inconsistency). Compared to non-obese patients, more obese patients (23% vs. 13%) had AVAI/AVA inconsistency (p<0.01) (Fig.1). Adjustment for pressure recovery reduced the prevalence of inconsistency, but also ELI/EL inconsistency was more common in the obese group (13% vs. 9%, p<0.05). In univariate analyses, AVAI/AVA and ELI/EL inconsistencies were predominantly found in men and associated with larger body size, lower stroke volume, higher pressure recovery and hypertension (all p<0.05). In multivariate regression analyses, adjusting for these covariates, 1 unit higher BMI was associated with 10 % higher prevalence of AVAI/AVA inconsistency (95% CI 1.07-1.14, p<0.001) and 8 % higher prevalence of ELI/EL inconsistency (95% CI 1.04-1.12, p<0.001), respectively.
Conclusion: In obese patients with asymptomatic, mild to moderate AS, using AVA and EL indexed for BSA in grading of stenosis may lead to overestimation of AS severity.
Figure 1:Prevalence of severe AS in obese versus non-obese patients graded by AVA and AVAI (*p<0.01)
- © 2013 by American Heart Association, Inc.