Adventitial vasa vasorum in balloon-injured coronary arteries - Visualization and quantitation by a microscopic three-dimensional computed tomographytechnique
Hm. Kwon et al., Adventitial vasa vasorum in balloon-injured coronary arteries - Visualization and quantitation by a microscopic three-dimensional computed tomographytechnique, J AM COL C, 32(7), 1998, pp. 2072-2079
Citations number
36
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Objectives. The objective of this study was to examine the quantitative res
ponse of the adventitial vasa vasorum to balloon-induced coronary injury.
Background. Recent attention has focused on the role of vasa vasorum in ath
erosclerotic and restenotic coronary artery disease. However, the three-dim
ensional anatomy of these complex vessels is largely unknown, especially af
ter angioplasty injury. The purpose of this study was to visualize and quan
titate three-dimensional spatial patterns of vasa vasorum in normal and bal
loon injured porcine coronary arteries. We also studied the spatial growth
of vasa vasorum in regions of neointimal formation. A novel imaging techniq
ue, microscopic computed tomography, was used for these studies. Methods. F
our pigs were killed 28 d after coronary balloon injury, and four pigs with
uninjured coronary arteries served as normal controls. The coronary arteri
es were injected with a low viscosity, radiopaque liquid polymer compound.
Normal and injured coronary segments were scanned using a microscopic compu
ted tomography technique. Three-dimensional reconstructed maximum intensity
projection and voxel gradient shading images were displayed at different a
ngles and voxel threshold values, using image analysis software. For quanti
tation, seven to 10 cross-sectional images (40 normal and 32 balloon injure
d cross-sections) were captured from each specimen at a voxel size of 21 mu
m.
Results. Normal vasa vasorum originated from the coronary artery lumen, pri
ncipally at large branch points. Two different types of vasa were found and
classified as first-order or second-order according to location and direct
ion. In balloon-injured coronary arteries, adventitial vasa vasorum density
was increased (3.16 +/- 0.17/mm(2) vs. 1.90 +/- 0.06/mm(2), p = 0.0001; re
spectively), suggesting neovascularization by 28 d after vessel injury. Als
o, in these injured arteries, the vasa spatial distribution was disrupted c
ompared with normal vessels, with proportionally more second-order vasa vas
orum. The diameters of first order and second order vasa were smaller in no
rmal compared with balloon-treated coronary arteries (p = 0.012 first-order
; p < 0.001, second order; respectively). The density of newly formed vasa
vasorum was proportional to vessel stenosis (r = 0.81, p = 0.0001). Althoug
h the total number of vasa was increased after injury, the total vascular a
rea comprised of vasa was significantly reduced in injured vessels compared
with normals (3.83 +/- 0.20% to 5.42 +/- 0.56%, p = 0.0185).
Conclusions. Adventitial neovascularization occurs after balloon injury. Th
e number of new vessels is proportional to vessel stenosis. These findings
may hold substantial implications for the therapy of vascular disease and r
estenosis. (J Am Coil Cardiol 1998;32:2072-9) (C) 1998 by the American Coll
ege of Cardiology.