Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone

Jeroen P. H. M. van den Wijngaard*, Henny Schulten, Pepijn van Horssen, Rene D. ter Wee, Maria Siebes, Mark J. Post, Jos A. E. Spaan

*Corresponding author for this work

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Abstract

van den Wijngaard JP, Schulten H, van Horssen P, ter Wee RD, Siebes M, Post MJ, Spaan JA. Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone. Am J Physiol Heart Circ Physiol 300: H1930-H1937, 2011. First published March 11, 2011; doi:10.1152/ajpheart.00403.2010. In the current paradigm on coronary collateral development, it is assumed that these vessels develop consequentially from increased fluid shear stress (FSS) through preexisting collateral arteries. The increased FSS follows from an increase in pressure gradient between the region at risk and well-perfused surroundings. The objective of this study was to test the hypothesis that, in the heart, collateral connections can form in the absence of an increased FFS and consequentially at any depth and region within the ventricular wall. In Yorkshire pigs, gradual left circumflex coronary artery occlusion was obtained over 6 wk by an ameroid constrictor, whereas the control group underwent a sham operation. Hearts were harvested and subsequently processed in an imaging cryomicrotome, resulting in 40-mu m voxel resolution three-dimensional reconstructions of the intramural vascular vessels. Dedicated software segmented the intramural vessels and all continuous vascular pathways containing a collateral connection. In the ameroid group, 192 collaterals, 22-1,049 mu m in diameter, were detected with 62% within the subendocardium. Sixty percent of collaterals bridged from the left anterior descending artery to left circumflex coronary artery. A novel result is that 25% (n = 48) of smaller-radius collaterals (P = 0.047) connected with both origin and terminus in the nontarget area where perfusion was assumed uncompromised. In the porcine heart, collateral vessels develop not only in ischemic border zones with increased FSS but also away from such border zones where increased FSS is unlikely. The majority of collaterals were located at the subendocardium, corresponding to the region with highest prevalence for ischemia.
Original languageEnglish
Pages (from-to)H1930-H1937
JournalAmerican Journal of Physiology-heart and Circulatory Physiology
Volume300
Issue number5
DOIs
Publication statusPublished - May 2011

Keywords

  • imaging cryomicrotome
  • collaterals
  • ischemia
  • remodeling
  • fluid shear stress

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