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Vascular changes in different stages of hypertension. Local peripheral resistance at reactive hyperaemia
Insights
Young individuals with borderline hypertension show functional autoregulation, while older hypertensive patients exhibit structural vascular changes. This impacts blood flow and resistance differently across hypertension stages.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Vascular Biology
Background:
- Hypertension is a complex condition affecting blood flow regulation.
- Understanding vascular adaptations in different hypertensive populations is crucial.
Purpose of the Study:
- To investigate calf blood flow and vascular resistance in young and older hypertensive individuals.
- To differentiate between functional and structural vascular changes in various hypertension types.
Main Methods:
- Measured resting and maximal calf blood flow during reactive hyperemia.
- Assessed blood pressure and calculated vascular resistance.
- Compared findings in borderline, juvenile, essential, and vasorenal hypertension with healthy controls.
Main Results:
- Resting blood flow was similar in young borderline/stage I hypertension and controls, but lower in older hypertensives.
- Maximal blood flow during reactive hyperemia was higher in borderline hypertension, similar in young stage I, and lower in all older hypertensive groups.
- Vascular resistance was elevated in most hypertensive groups, except borderline hypertension.
Conclusions:
- Borderline hypertension in young individuals may involve only functional autoregulation.
- Advanced hypertension stages (I and II) and vasorenal hypertension show structural vascular adaptations (hypertrophy).
- Age and hypertension severity significantly influence vascular responses and resistance.
Abstract:
The resting and the maximal calf blood flows at reactive hyperaemia and blood pressure were determined in a group of young persons with borderline and juvenile hypertension (stage I) and in older patients with essential (stage I and II according to WHO) and vasorenal hypertension. The findings were compared with those found in healthy controls of the same age span. The resting blood flow was the same in borderline hypertension and in HPT stage I in young persons as in the control group; in older hypertensives it was significantly lower. The maximal blood flow at reactive hyperaemia was significantly higher in the group of borderline HPT, did not differ in HPT stage I in young subjects, and was significantly lower in older subjects in all stages of HPT. A significantly higher vascular resistance was found in all groups of hypertensives except the borderline HPT both at rest and at reactive hyperaemia. The results suggest that in persons with borderline HPT only functional autoregulation takes place, whereas in HPT stage I and II and in vasorenal HPT the high vascular resistance is already an expression of structural adaption of the vascular wall in the form of its hypertrophy.