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Updated: May 7, 2026

Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots
Published on: May 21, 2017
A novel functional index, aortic-valve-coefficient, for assessing aortic-stenosis in patients undergoing TAVR: A
Shreyash M Manegaonkar1, Rishi Sukhija2, Mohamed A Effat2
1Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA.
Background:
Evaluating the severity of aortic stenosis (AS) can be challenging, particularly in patients with low-gradient (LG, Δp < 40 mmHg) AS.
Objective:
This study aims to improve the accuracy of assessing severity of AS using a novel functional index- Aortic Valve Coefficient (AVC). The AVC is defined as ratio of mean transvalvular pressure-drop (Δp) to the proximal dynamic pressure (1/2 × blood density × VLVOT2; VLVOT: left ventricular outflow tract peak velocity).
Hypothesis:
AVC, developed from fundamental fluid dynamic principles, is a better index for accessing AS severity as it incorporates square of VLVOT and downstream pressure recovery.
Methods:
This pilot prospective study enrolled 47 patients undergoing TAVR for AS. Using cardiac-catheterization-measured Δp and echocardiography-Doppler-derived VLVOT, AVC was evaluated. Pre- and post-TAVR pressure-velocity measurements were obtained, resulting in a dataset with 78 data points, including 32 data points specifically linked to LG AS. Linear regression analysis was performed to correlate AVC with Δp, VLVOT and aortic-valve-area. Welch 2-sample t-test was carried out to compare the means of AVC against aortic-valve-area.
Results:
Moderate correlation (r = 0.85) was observed between AVC and aortic-valve-area indicating AVC could be a prospective index. However, correlation decreased (r = 0.75) in LG AS patients, indicating increased discordancy. Comparing AVC and aortic-valve-area in LG AS patients with left ventricular ejection fraction (LVEF) < 50 % and LVEF ≥50 %, t-test showed that AVC values are significantly different (p < 0.05) as compared to aortic-valve-area (p = 0.48).
Conclusion:
AVC, a novel index, has the potential to improve assessment of AS severity and clinical decision making for treating patients with AS.
Condensed Abstract:
Complex hemodynamics, such as paradoxical "low-flow low-gradient (LG)" Aortic stenosis (AS) can be difficult to diagnose. Currently, mean transvalvular pressure-drop and flow-derived aortic-valve-area assess AS severity. Aortic valve coefficient (AVC) is a novel index which combines both pressure-drop and flow measurements to assess the severity of AS. A total of 47 patients (72 data points) were studied undergoing TAVR. In LG AS patients, t-test comparing left ventricular ejection fraction (LVEF) < 50 % and LVEF ≥50 % showed that AVC are significantly different (p < 0.05) as compared to aortic-valve-area (p = 0.48). Therefore, AVC could be a better index.
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