EFFECTS OF DRUG TREATMENT ON HUMAN RESISTANCE ARTERIOLE MORPHOLOGY IN ESSENTIAL HYPERTENSION: DIRECT EVIDENCE FOR STRUCTURAL REMODELLING OF RESISTANCE VESSELS

To examine whether effective drug treatment would revese the morphological changes in resistance arterioles which characterise untreated essential hypertension, the vessels' media thickness and contractility were measured before and after long-term treatment. Nine patients underwent skin biopsy before and after a mean 13 months of antihypertensive treatment (range 4-24 months). Subcutaneous resistance arterioles were dissected and mounted in a myograph. Treatment did not affect the shift in sensitivity to noradrenaline in the presence of cocaine, sensitivity to exogenously administered calcium, and the rate of relaxation after withdrawal of vasoconstrictor stimuli. The media/lumen ratio fell significantly (p = 0·011) owing to a significant regression in media thickness (p=0·0195), but this was not complete. Thus, effective antihypertensive treatment can reverse some of the structural change observed in the untreated state, although it apparently does not affect calcium sensitivity or relaxation rate; these features are thought to be consequences of the disease after it has become established.