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Transmural variation and anisotropy of microvascular flow conductivity in the rat left ventricular myocardium (675.4)
Author(s) -
Smith Amy,
Shipley Rebecca,
Lee Jack,
Sands Gregory,
LeGrice Ian,
Smith Nicolas
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.675.4
Subject(s) - endocardium , anisotropy , perfusion , diastole , capillary action , materials science , biomedical engineering , permeability (electromagnetism) , anatomy , chemistry , cardiology , physics , medicine , membrane , composite material , optics , biochemistry , blood pressure
Three‐dimensional (3D) ex vivo data on microvascular anatomy in the myocardium is used to determine the transmural gradient in fluid transport properties via mathematical averaging methods. The 3D capillary network is modeled as a porous medium, whose conductivity is quantified in terms of a permeability tensor. This metric is directly computed by volume‐averaging blood flow solutions in model networks with geometrical and topological properties derived from an anatomically‐detailed data set recently extracted from the rat left ventricular myocardium using confocal microscopy, high‐precision sectioning and image processing techniques. Results showed that the permeability was strongly anisotropic: the network was approximately ten times more permeable in the principal direction of capillary alignment (the ‘longitudinal’ direction) than perpendicular to this direction. Structural properties of the network varied smoothly from subepicardium to subendocardium, with a 30% transmural increase in capillary diameter translating to a 130% rise in permeability in the longitudinal direction. This supports the hypothesis that perfusion is preferentially facilitated during ventricular diastole in the subendocardial microvasculature to compensate for severely‐reduced systolic perfusion in the subendocardium. Grant Funding Source : Supported by NIH GM094503‐1, EPSRC EP/F043929/1 and EP/G007527/2, and Award KUK‐C1‐013‐0 from KAUST.