Key result
Among patients without valvular obstruction, an aortic valve area ≤1.0 cm2 was found in 1.8% of those with aortic sclerosis and 0.5% of those with normal valves, risking overestimation of AS.
Why the study?
To establish reference values for aortic valve area (AVA) in a large population and evaluate the risk of overestimating aortic stenosis when relying on flow-corrected severity indices.
Observational (n=16,156)
No
Absolute Event Rate: 1.8% vs 0.5%
Normal values of continuity-equation derived AVA are smaller than previously considered, suggesting that flow-corrected indices may overestimate aortic stenosis severity in patients without true obstruction.
May urge caution grading AS severity by AVA in aortic sclerosis; leaves open whether continuity-equation thresholds need revision.
Objective To obtain reference values of aortic valve area (AVA) in a large population and to infer the risk of overestimating aortic stenosis (AS) when focusing on flow-corrected indices of severity. Methods We prospectively measured indices of AS in all consecutive echocardiograms performed in a large referral cardiac imaging laboratory for 1 year. We specifically analysed the distribution of AVA, indexed AVA and velocity ratio (Vratio) in patients with and without AS, the latter defined as the coexistence of valvular outflow obstruction (Vmax ≥2.5 m/s) and morphological findings of valve degeneration. Results 16 156 echocardiograms were analysed, 14 669 of which did not show valvular obstruction (peak jet velocity <2.5 m/s). In the latter group, AVA was 2.6±0.7 cm 2 in 8190 studies with normal valves and 2.3±0.7 cm 2 in 6479 studies with aortic sclerosis (AScl). There was a relatively wide overlap between values of AVA, indexed AVA and velocity ratio between studies of patients with AScl and AS. Values of AVA ≤1.0 cm 2 were found in 0.5% of studies with normal valves and 1.8% of studies with AScl. These proportions were 3.1% and 9.3% for AVA ≤1.5 cm 2 , respectively. Vratio ≤0.25 were found in 0.1% of patients without obstruction. Risk factors for a small AVA in patients without obstruction were AScl, female sex, small body surface area, low ejection fraction and mitral regurgitation. Conclusions Normal values of continuity-equation derived AVA are smaller than previously considered. AVA values below cutoffs of moderate or severe AS can be found in patients without the disease. Flow-corrected indices may overestimate AS in patients with low gradients, particularly in the presence of well-identified risk factors.
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González‐Mansilla et al. (2019) conducted an observational in Aortic stenosis (n=16,156). Aortic sclerosis vs. Normal valves was evaluated on Aortic valve area ≤1.0 cm2. Among patients without valvular obstruction, an aortic valve area ≤1.0 cm2 was found in 1.8% of those with aortic sclerosis and 0.5% of those with normal valves, risking overestimation of AS.
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