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Updated: May 12, 2026
In Vitro Model of Physiological and Pathological Blood Flow with Application to Investigations of Vascular Cell Remodeling
Published on: November 3, 2015
Benchtop Flow Stasis Quantification: In Vitro Methods and In Vivo Possibilities.
Vahid Sadri1,2, Prem A Midha1,3, Immanuel David Madukauwa-David1
1Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Technology Enterprise Park, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
This study introduces a new fluoroscopic method to measure flow stasis around heart valves, crucial for predicting thrombosis. The contrast attenuation ratio (CAR) accurately assesses flow and can be used in clinical practice for risk stratification.
Area of Science:
- Cardiovascular Imaging
- Biomedical Engineering
- Fluid Dynamics
Background:
- Neo-sinus flow stasis is linked to transcatheter heart valve (THV) thrombosis.
- Traditional flow quantification methods lack optical access or require modified devices.
- En face and fluoroscopic videodensitometry offer alternative visualization of washout.
Purpose of the Study:
- To compare two in vitro methods for assessing flow stasis in regions with limited optical access.
- To introduce and validate the contrast attenuation ratio (CAR) as a novel metric for flow stasis.
- To assess the clinical feasibility and utility of CAR in routine fluoroscopy.
Main Methods:
- Paired in vitro experiments using laser-enhanced video densitometry (LEVD) and fluoroscopic video densitometry (FVD).
- Calculation of washout time as a measure of flow stasis.
- Development and retrospective analysis of the contrast attenuation ratio (CAR) from 72 clinical fluoroscopic datasets.
Main Results:
- In vitro fluoroscopic assessment of neo-sinus flow stasis correlated well with LEVD (r²=0.77).
- The CAR metric showed strong agreement with washout time (r²=0.91) and allowed analysis of incomplete data.
- CAR averaged 10.6±4.6% in 72 retrospective patient datasets, demonstrating clinical obtainability.
Conclusions:
- Two in vitro methods effectively assess flow stasis in optically inaccessible areas around implants.
- Fluoroscopic benchtop techniques validated CAR for routine clinical use.
- CAR is an accurate, clinically obtainable metric for potential valve thrombosis risk stratification.
