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Control of the Coronary Flow

Mechanics and Function of Organs, Tissues and Cells

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Control of the Coronary Flow 

Coronary flow is controlled to closely match myocardial metabolic demand. The coronary system has the capacity to increase flow up to six times its level under rest.  This capacity is severely compromised in vascular pathologies such as hypertension and atherosclerosis. Flow regulation is achieved by adjustment of vascular resistance via local diameter changes induced by the arterial smooth muscle cells (SMC), partially through endothelial mechano-transduction. Three mechanisms of SMC tone-regulation exist: 1) metabolic regulation, believed to affect small arterioles, 2) myogenic control by which vessel constrict/dilate in direct response to trans-luminal pressure, and 3) shear induced mechanism - tone is regulated in response to shear stress. There are major questions regarding the mutual interaction of these flow regulation mechanisms and the significance of their dependence on the vessel size and the effects of the network structure. These questions cannot be experimentally studied.

Our research addresses these issues by developing and validating a regulated coronary network dynamic flow analysis incorporating experimentally-derived single vessel control features and anatomically accurate 3-D network reconstruction. Preliminary model predictions of the effects of autoregulation (myogenic-induced maintenance of constant flow under varying perfusion pressure) exhibit similarity to observations.

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Network Reconstruction: Image of reconstructed arterial (red) and venous (blue ) coronary vessels

 

 Autoregulation: Model predicted coronary flow under variations of perfusion pressure without (broken line) and with (solid line) myogenic regulation.