Remodelling of the left anterior descending artery in a porcine model of supravalvular aortic stenosis.
BACKGROUND
Knowledge of the adaptive mechanisms of structure and function of coronary arteries in response to physical stress is important in human health and disease.


OBJECTIVE
To gain a better understanding of the adaptive mechanisms of morphology in the zero-stress state of the coronary arteries in a porcine model of hypertension and flow overload.


METHODS
The effects of simultaneous increases in pressure and flow were examined by studying the left anterior decending (LAD) artery in supravalvular aortic stenosis (SVAS). In this model, the pressure is uniformly increased along the length of the LAD artery trunk, whereas the increase in flow is significantly greater in the proximal than in the distal artery. The longitudinal variation of vessel dimension, medial and adventitial area, opening angle and residual strains were examined in the LAD arteries of aortic-banded (n = 5) and control (n = 5) pigs.


RESULTS
Our results show that the wall shear stress was normalized, whereas the circumferential stress was increased, in the proximal portion of the LAD artery after 5 weeks of SVAS. In the distal artery, both shear and circumferential stresses were normalized. The vessel wall area was also increased in the remodelled vessels as the result of an increase in the medial and adventitial area.


CONCLUSIONS
The major conclusion of this study is that, in the SVAS model, the remodelling process of the coronary artery is consistent with normalization of shear stress despite an increase in the circumferential stress. Furthermore, the remodelling of the zero-stress state is also dominated by flow overload.
Kassab
Ghassan S
GS
Department of Biomedical Engineering, University of California, Irvine 92697, USA. gkassab@uci.edu
Gregersen
Hans
H
Nielsen
Sten L
SL
Lu
Xiao
X
Tanko
Laszlo B
LB
Falk
Erling
E
D000222:Adaptation, Physiological; D000818:Animals; D021921:Aortic Stenosis, Supravalvular / Q000503:physiopathology*; D001158:Arteries / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology*; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D012039:Regional Blood Flow; D013314:Stress, Mechanical; D013552:Swine; D013997:Time Factors