Structural determinants of vascular resistance properties in hypertension. Haemodynamic and model analysis

Abstract

The average internal radius (r(i)) of the resistance vessels of the hindquarter (HQ) bed was narrower in renovascular and genetic hypertension than in normotensive controls. The narrowing was approximately uniform over the full range of vasomotor tone, which accounted for the bed's property as an 'amplifier' of vascular resistance (R) (increased slope (S) of the dose-R response curve) and for the elevated R at maximum dilatation (R(min)). In the model we examined the effects on the dose-R curve parameters of altering wall/internal radius (w/r(i)) ratio, r(i) and wall 'stiffness' one at a time, whilst the others were held constant: only narrowing of r(i) led to increases in both S and R(min);..