Reducing the Inconsistency between Doppler and Invasive Measurements of the Severity of Aortic Stenosis Using Aortic Valve Coefficient: A Retrospective Study on Humans
Background. It is not uncommon to observe inconsistencies in the diagnostic parameters derived from Doppler and catheterization measurements for assessing the severity of aortic stenosis (AS) which can result in suboptimal clinical decisions. In this pilot study, we investigate the possibility of improving the concordance between Doppler and catheter assessment of AS severity using the functional diagnostic parameter called aortic valve coefficient (AVC), defined as the ratio of the transvalvular pressure drop to the proximal dynamic pressure. Method and Results. AVC was calculated using diagnostic parameters obtained from retrospective chart reviews. AVC values were calculated independently from cardiac catheterization ( ) and Doppler measurements ( ). An improved significant correlation was observed between Doppler and catheter derived AVC ( , ) when compared to the correlation between Doppler and catheter measurements of mean pressure gradient ( , ) and aortic valve area ( , ). The correlation between Doppler and catheter derived AVC exhibited a marginal improvement over the correlation between Doppler and catheter derived aortic valve resistance ( , ). Conclusion. AVC is a refined clinical parameter that can improve the concordance between the noninvasive and invasive measures of the severity of aortic stenosis. 1. Introduction Aortic stenosis (AS) is a type of valvular heart disease that results from abnormal narrowing of the aortic valve opening. A stenotic aortic valve creates an increased pressure gradient between the left ventricle and the aorta. The resulting increased ventricular workload and associated increased ventricular wall stress may contribute to left ventricular dysfunction and heart failure over time. AS is typically caused by progressive degeneration and calcification of the aortic valve; hence, the prevalence of calcific aortic valve disease increases with age [1, 2]. Calcific aortic valve disease ranges from mild valve thickening with minimal flow obstruction termed aortic sclerosis to severe calcification and flow obstruction termed AS. Generally, aortic valve replacement is indicated for symptomatic severe AS, since the outcome without valve replacement is poor with survival rates as low as 50% at two years [3–5]. Accurate assessment of the severity of stenosis is critical for clinical decision making in patients with AS. Severity of AS is currently assessed by one or more diagnostic indices obtained by Doppler echocardiography and/or cardiac catheterization [6, 7]. Severity of AS is currently assessed by Doppler
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