Coronary Blood Flow Is Increased in RV Hypertrophy, but the Shape of Normalized Waves Is Preserved Throughout the Arterial Tree.

Yunlong Huo,Ghassan S Kassab

doi:10.3389/fphys.2018.00675

Abstract

A pulsatile hemodynamic analysis was carried out in the right coronary arterial (RCA) tree of control and RV hypertrophy (RVH) hearts. The shape of flow and wall shear stress (WSS) waves was hypothesized to be maintained throughout the RCA tree in RVH (i.e., similar patterns of normalized flow and WSS waves in vessels of various sizes). Consequently, we reconstructed the entire RCA tree down to the first capillary bifurcation of control and RVH hearts based on measured morphometric data. A Womersley-type model was used to compute the flow and WSS waves in the tree. The hemodynamic parameters obtained from experimental measurements were incorporated into the numerical model. Given an increased number of arterioles, the mean and amplitude of flow waves at the inlet of RCA tree in RVH was found to be two times larger than that in control, but no significant differences (p > 0.05) were found in precapillary arterioles. The increase of stiffness in RCA of RVH preserved the shape of normalized flow and WSS waves, but increased the PWV in coronary arteries and reduced the phase angle difference for the waves between the most proximal RCA and the most distal precapillary arteriole. The study is important for understanding pulsatile coronary blood flow in ventricular hypertrophy.

Highlights

There is compensatory vascular remodeling that accompanies RV hypertrophy (RVH) (Cooper et al, 1981; Manohar et al, 1981; Botham et al, 1984; Manohar, 1985; White et al, 1992; Kassab et al, 1993)
The steady-state flows were measured under loading and unloading of pressures as the right coronary artery (RCA) tree was perfused by cardioplegic solution, which were consistent with the computed pulsatile flows with the frequency approaching to zero since a steady-state flow can be mimicked by a pulsatile flow as ω → 0
Based on morphometric measurements and steady-state hemodynamic analysis, the remodeling of structure and function of the entire RCA tree was determined in RVH after 5 weeks of pulmonary banding (Kassab et al, 1993; Huo et al, 2007)

Summary

Introduction

There is compensatory vascular remodeling that accompanies RV hypertrophy (RVH) (Cooper et al, 1981; Manohar et al, 1981; Botham et al, 1984; Manohar, 1985; White et al, 1992; Kassab et al, 1993). The increase of blood flow was found to be caused by the compensatory growth of small vessels, which resulted in restoration of blood flow and wall shear stress (WSS) to normal level in the perfusion arterioles (diameter

Methods

Results

Conclusion