Coronary remodeling and biomechanics: Are we going with the flow in 2020?

Abstract

Under normal conditions, coronary blood flow (CBF) provides critical blood supply to the myocardium so that it can appropriately meet the metabolic demands of the body. Dogmatically, there exist several known regulators and modulators of CBF that include local metabolites and neurohormonal factors that can influence the function of the coronary circulation. In disease states such as diabetes and myocardial ischemia, these regulators are impaired or shifted such that CBF is reduced. Although functional considerations have been and continued to be well studied, more recent evidence builds upon established studies that collectively suggest that the relative roles of coronary structure, biomechanics, and the influence of cardiac biomechanics via extravascular compression may also play a significant role in dictating CBF. In this mini review, we discuss these regulators of CBF under normal and pathophysiological conditions and their potential influence on the control of CBF.

Keywords: biomechanics; coronary blood flow; function; stiffness; structure.

Figure 1.

Coronary blood flow (CBF) is regulated by a myriad of physiological parameters. Conventionally, studies have focused on one of these parameters, however, under pathological conditions, typically more than one of these parameters goes awry. In this figure we depict how structural (A), biomechanical (B), and extravascular (C) parameters may change during normal and pathological conditions. Typically, functional changes are due to vasodilation or vasoconstriction to maintain CBF. Structural modifications may include changes in radius, wall thickness, and vessel length. Biomechanical factors include vessel material properties (i.e., stiffness), and forces acting on the vessels (e.g., shear, longitudinal, radial, and circumferential stresses). Extravascular alterations may include changes in myocardial stiffness and changes in viscosity. The figure was created using www.BioRender.com with permission.