title: The role of wall shear stress in the assessment of right ventricle hydraulic workload.
abstract: Pulmonary hypertension (PH) is a devastating disease affecting approximately 15-50 people per million, with a higher incidence in women. PH mortality is mostly attributed to right ventricle (RV) failure, which results from RV hypotrophy due to an overburdened hydraulic workload. The objective of this study is to correlate wall shear stress (WSS) with hemodynamic metrics that are generally accepted as clinical indicators of RV workload and are well correlated with disease outcome. Retrospective right heart catheterization data for 20 PH patients were analyzed to derive pulmonary vascular resistance (PVR), arterial compliance (C), and an index of wave reflections (Γ). Patient-specific contrast-enhanced computed tomography chest images were used to reconstruct the individual pulmonary arterial trees up to the seventh generation. Computational fluid dynamics analyses simulating blood flow at peak systole were conducted for each vascular model to calculate WSS distributions on the endothelial surface of the pulmonary arteries. WSS was found to be decreased proportionally with elevated PVR and reduced C. Spatially averaged WSS (SAWSS) was positively correlated with PVR (R (2) = 0.66), C (R (2) = 0.73), and Γ (R (2) = 0.5) and also showed promising preliminary correlations with RV geometric characteristics. Evaluating WSS at random cross sections in the proximal vasculature (main, right, and left pulmonary arteries), the type of data that can be acquired from phase-contrast magnetic resonance imaging, did not reveal the same correlations. In conclusion, we found that WSS has the potential to be a viable and clinically useful noninvasive metric of PH disease progression and RV health. Future work should be focused on evaluating whether SAWSS has prognostic value in the management of PH and whether it can be used as a rapid reactivity assessment tool, which would aid in selection of appropriate therapies.
authors.affiliation: Department of Biomedical Engineering, University of Texas, San Antonio, Texas, USA.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Kheyfets
authors.affiliation: Department of Biomedical Engineering, University of Texas, San Antonio, Texas, USA.
authors.forename: Mirunalini
authors.initials: M
authors.lastname: Thirugnanasambandam
authors.affiliation: Department of Biological Sciences, University of Texas, San Antonio, Texas, USA.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Rios
authors.affiliation: Department of Mechanical Engineering, University of Texas, San Antonio, Texas, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Evans
authors.affiliation: Department of Cardiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: Triston
authors.initials: T
authors.lastname: Smith
authors.affiliation: Department of Radiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: Theodore
authors.initials: T
authors.lastname: Schroeder
authors.affiliation: Department of Radiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Mueller
authors.affiliation: Department of Cardiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Murali
authors.affiliation: Department of Cardiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: David
authors.initials: D
authors.lastname: Lasorda
authors.affiliation: Department of Cardiology, McGinnis Cardiovascular Institute, Allegheny General Hospital, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Spotti
authors.affiliation: Department of Biomedical Engineering, University of Texas, San Antonio, Texas, USA.
authors.forename: Ender
authors.initials: E
authors.lastname: Finol
keywords: computational fluid dynamics; pulmonary hypertension; pulmonary vascular resistance; right ventricle; wall shear stress