Invited Symposium: Hypertension I: Structure of Small Arteries in Hypertension
Essential hypertension is haemodynamically characterised by increases in peripheral vascular resistance and normal cardiac output. Blood flow is modified by small blood vessels and in order to investigate morphological alterations in hypertension, techniques have been established which allow structure to be mathematically predicted or precisely measured. Such methods deliver remarkable concordance with a reduction in lumen diameter of 7-8% and an increase in media thickness:lumen diameter ratio is associated with the level of pressure, and morphology correlates with left ventricular mass. Pressure is the major determinant of structure. The change itself is due to a re-arrangement of tissue around a narrower lumen, with an increase in medial layers (eutrophic inward remodelling). Also there is a small contribution from hypertrophy. Such changes are found in vascular beds including subcutaneous fat, intestinal and intramyocardial arteries. In the heart this fixed structural change may be pathologically important by reducing vascular reserve. In the Ren II transgenic rat, remodelling is associated with over expression of an integrin. Trials have suggested ACE inhibitors may be superior in reversing remodelling which may be clinically important: if vascular reserve were improved in the coronary circulation, the cardiovascular event rate in treated hypertension might be reduced further.
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|Heagerty, AM; (1998). The Structure of Small Arteries in Essential Hypertension. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium. Available at URL http://www.mcmaster.ca/inabis98/mulvany/heagerty0861/index.html|
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