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Flow pattern and structural changes at carotid bifurcation in hypertensive cynomolgus monkeys
M Hennerici1, K F Bürrig, M Daffertshofer
1Department of Neurology, University of Düsseldorf, FRG.
Hypertension (Dallas, Tex. : 1979)
|April 1, 1989
Summary
Systemic hypertension induced by aortic coarctation caused significant changes in blood flow and carotid artery morphology in M. fascicularis. These hemodynamic alterations in the carotid bulb may contribute to early atherogenesis.
Area of Science:
- Vascular biology
- Hemodynamics
- Cardiovascular research
Background:
- Systemic hypertension is a major risk factor for cardiovascular disease.
- Understanding the early vascular changes in response to hypertension is crucial for disease prevention.
- The extracranial carotid system plays a vital role in cerebral blood supply and is susceptible to hypertensive damage.
Purpose of the Study:
- To investigate the effects of surgically induced systemic hypertension on blood flow patterns and morphology in the extracranial carotid arteries of M. fascicularis.
- To elucidate the role of cerebral autoregulation in response to hypertension.
- To explore the association between hemodynamic alterations and early atherogenesis in the carotid bulb.
Main Methods:
- Surgical coarctation of the thoracic aorta was used to induce systemic hypertension in M. fascicularis.
- Intra-arterial hemodynamics were assessed using continuous-wave Doppler signal spectrum analysis and multigate pulsed-wave Doppler flow velocity profile processing.
- Morphological changes in the carotid arteries were evaluated at various time points post-surgery.
Main Results:
- Hypertension led to diminished peak frequencies throughout the carotid system.
- Enlargement of the lumen diameter was observed in the common carotid artery and carotid bulb.
- The internal carotid artery showed diminished lumen diameter, transforming the carotid bulb into a region of structural and hemodynamic transition, with increased flow irregularities.
- Endothelial disarray, leucocytic adherence, and activation were noted in the carotid bulb.
Conclusions:
- Cerebral autoregulation may contribute to the observed morphological changes under high intracranial vascular resistance.
- Hemodynamic alterations and associated endothelial changes in the carotid bulb are implicated in early atherogenesis.
- This study provides insights into the initial vascular responses to hypertension, relevant to understanding atherosclerosis development.