Importance of hypertrophy of resistance vessels in humans in different stages of hypertension.

One of the causes of fixation of elevated blood pressure are structural changes in the arterial wall manifested at first by hypertrophy of the smooth muscle and later by proliferation of connective tissue. These changes can be evaluated in humans from the degree of vasodilatation during reactive hyperaemia. We found that the inability of adequate vasodilatation is typical for all types of hypertension, i.e. essential hypertension in young and elderly subjects stage I and II, and vasorenal hypertension. On the other hand, in patients with borderline hypertension structural changes do not develop. The inability of adequate vasodilatation in patients with hypertension persists also during a short-term reduction of the blood pressure to normal values as a result of therapy. In patients operated successfully on account of vasorenal hypertension the normal vasodilatation capacity is regained after one year of normalization of blood pressure.