Abstract 9778: Harmonizing Cutoff Values for Severe Aortic Valve Stenosis

Abstract

Background: Decision making in patients with aortic valve stenosis (AS) and normal left ventricular function may be complicated by inconsistencies in cutoff values for severe AS. Particularly, the constellation of severe stenosis according to aortic valve area (AVA) <1cm² and non-severe stenosis according to mean pressure gradient (MPG) ≤40mmHg is a frequent finding which may, at least in part, be due to systematic discrepancies between cutoff values.

Methods: We evaluated the effect of adjusting the cutoff value for severe AS from AVA 1.0cm² to 0.8cm² on discrepancies in classification of severity and event rates in 1525 asymptomatic patients with normal ejection fraction prospectively followed for a mean of 46 months from the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study.

Results: The diagnosis of a severe AS was made in 56 (4%) patients according to the MPG >40mmHg criterion, in 470 (31%) based on an AVA of <1.0cm² and in 185 (12%) with an AVA of <0.8cm². After dividing the population into quintiles according to AVA and MPG an aortic valve related event rate of 0.40 was observed in patients with a mean AVA of 1.0±0.1cm² which was similar to patients with a MPG of 27±2mmHg (0.40, p=ns). In turn, patients with a MPG of 37±5mm had an event rate of 0.65 and patients with an AVA of 0.74±0.1cm² had an event rate of 0.53 (figure). Cardiovascular death rates followed a similar pattern.

Conclusion: Adjusting the cutoff value for severe stenosis in patients with normal left ventricular function from AVA 1.0cm² to 0.8cm² may harmonize parameters for the assessment of aortic stenosis both with respect to stenosis severity as well as clinical outcome.