Perfusion territories subtended by penetrating coronary arteries increase in size and decrease in number toward the...

Area of Science:

• Cardiovascular Physiology
• Biomedical Imaging
• Computational Biology

Background:

• Myocardial blood flow and risk areas in coronary artery disease depend on intramural vascular structure.
• Intramural vasculature knowledge is vital for advanced multiscale and multiphysics cardiac modeling.

Purpose of the Study:

• To quantitatively analyze the three-dimensional structure of intramural vascular crowns.
• To characterize perfusion territories and vascular volume density across myocardial layers.

Main Methods:

• Analysis of eight canine hearts using a high-resolution imaging cryomicrotome.
• Skeletonization of vasculature and definition of vascular crowns for each penetrating artery.
• Three-dimensional Voronoi tessellation for classifying perfusion territories (subendocardial, midmyocardial, subepicardial).

Main Results:

• Subendocardial regions have fewer, larger perfusion territories (~0.5 ml) compared to the subepicardium's numerous small territories (~0.01 ml).
• Vascular volume density of small arteries (<400 μm) is significantly higher in subendocardial (3.2%) than subepicardial (0.8%) territories.
• Differences in vascular density correlate with cardiac contraction forces and result in distinct scaling laws for vascular volume and tissue mass.

Conclusions:

• Novel 3D quantitative analysis provides insights into intramural vascular architecture and perfusion heterogeneity.
• Findings can inform patient-specific computational models for coronary perfusion.
• This data may improve interpretation of clinical imaging methods for assessing transmural perfusion distribution.