Annals of Biomedical Engineering

, Volume 45, Issue 5, pp 1305–1314 | Cite as

Aortic Regurgitation Generates a Kinematic Obstruction Which Hinders Left Ventricular Filling

  • Ikechukwu Okafor
  • Vrishank Raghav
  • Jose F. Condado
  • Prem A. Midha
  • Gautam Kumar
  • Ajit P. YoganathanEmail author


An incompetent aortic valve (AV) results in aortic regurgitation (AR), where retrograde flow of blood into the left ventricle (LV) is observed. In this work, we parametrically characterized the detailed changes in intra-ventricular flow during diastole as a result of AR in a physiological in vitro left-heart simulator (LHS). The loss of energy within the LV as the level of AR increased was also assessed. The validated LHS consisted of an optically-clear, flexible wall LV and a modular AV holder. Two-component, planar, digital particle image velocimetry was used to visualize and quantify intra-ventricular flow. A large coherent vortical structure which engulfed the whole LV was observed under control conditions. In the cases with AR, the regurgitant jet was observed to generate a “kinematic obstruction” between the mitral valve and the LV apex, preventing the trans-mitral jet from generating a coherent vortical structure. The regurgitant jet was also observed to impinge on the inferolateral wall of the LV. Energy dissipation rate (EDR) for no, trace, mild, and moderate AR were found to be 1.15, 2.26, 3.56, and 5.99 W/m3, respectively. This study has, for the first time, performed an in vitro characterization of intra-ventricular flow in the presence of AR. Mechanistically, the formation of a “kinematic obstruction” appears to be the cause of the increased EDR (a metric quantifiable in vivo) during AR. EDR increases non-linearly with AR fraction and could potentially be used as a metric to grade severity of AR and develop clinical interventional timing strategies for patients.


Left ventricle filling Vortex flow Aortic regurgitation Energy dissipation Aortic valve 



We would like to thank VenAir (Terrassa-Barcelona, Spain) for casting the silicone LV, the machine shop personnel at the School of Chemical and Biomolecular Engineering at Georgia Tech for machining the LHS, and finally Procter & Gamble for providing the glycerin used in this work. Funding was provided by American Heart Association (Grant No. 16POST27520030).

Conflict of Interests

The authors have no conflicts of interests to disclose.

Supplementary material

Supplementary material 1 (MP4 5375 kb)

Supplementary material 2 (MP4 6207 kb)

10439_2017_1790_MOESM3_ESM.mp4 (3.2 mb)
Supplementary material 3 (MP4 3253 kb)

Supplementary material 4 (MP4 6196 kb)

10439_2017_1790_MOESM5_ESM.tif (1.2 mb)
Supplementary material 5 (TIFF 1230 kb) Supplementary Figure 1: Out of plane vorticity color map overlaid with streamlines for the plane 5 mm offset from the central LVOT plane of the mild AR case at T = (a) 0.05 s, start E-wave, (b) 0.15 s, peak E-wave, (c) 0.275 s, end E-wave, and (d) 0.5 s, peak A-wave


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Copyright information

© Biomedical Engineering Society 2017

Authors and Affiliations

  • Ikechukwu Okafor
    • 1
    • 2
  • Vrishank Raghav
    • 3
    • 4
  • Jose F. Condado
    • 5
  • Prem A. Midha
    • 6
  • Gautam Kumar
    • 5
    • 7
  • Ajit P. Yoganathan
    • 1
    • 3
    Email author
  1. 1.School of Chemical and Biomolecular EngineeringGeorgia Institute of TechnologyAtlantaUSA
  2. 2.Exponent Failure Analysis AssociatesPhiladelphiaUSA
  3. 3.Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory UniversityAtlantaUSA
  4. 4.Department of Aerospace EngineeringAuburn UniversityAuburnUSA
  5. 5.Division of CardiologyEmory University HospitalAtlantaUSA
  6. 6.Woodruff School of Mechanical Engineering, Georgia Institute of TechnologyAtlantaUSA
  7. 7.Atlanta Veterans Affairs Medical CenterDecaturUSA

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