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Characteristics of the limb circulation in hypertension
1Semmelweis Medical University, Cardiovascular Surgical Clinic, Budapest, Hungary.
Insights
Hypertension elevates limb vascular resistance, impacting limb blood flow regulation. This study reveals that while hypertension alone increases resistance, combined with peripheral obliterative arterial disease, it severely reduces blood flow.
Area of Science:
- Cardiovascular Physiology
- Vascular Medicine
- Hypertension Research
Background:
- Hypertension is a significant risk factor for cardiovascular diseases.
- Understanding its impact on peripheral circulation is crucial for patient management.
- Peripheral obliterative arterial disease (POAD) further complicates limb blood flow.
Purpose of the Study:
- To investigate the effects of hypertension on limb circulation regulation.
- To compare limb blood flow and vascular resistance in hypertensive and normotensive individuals.
- To assess the impact of co-existing POAD on limb circulation in hypertensive patients.
Main Methods:
- Study included 50 hypertensive patients and 67 normotensive controls.
- Patients were categorized based on intact peripheral circulation or presence of POAD.
- Limb blood flow (LBF) measured using venous isotope dilution technique.
Main Results:
- Hypertensive patients showed markedly elevated limb vascular resistance (LVR) with normal LBF.
- Patients with both hypertension and POAD exhibited pathologically elevated LVR and diminished LBF.
- Vasodilator therapy increased LBF by decreasing LVR, despite a drop in blood pressure.
Conclusions:
- Elevated LVR is the most characteristic change in limb circulation due to hypertension.
- Increased arterial blood pressure does not favorably affect limb circulation in hypertensive individuals.
- Limb blood flow is relatively low compared to blood pressure in hypertensive patients.
Abstract:
The aim of this study was to investigate the effect of hypertension on the regulation of limb circulation. The study group consisted of 50 patients suffering from hypertension; in 21 cases the peripheral circulation was intact, while 29 patients had peripheral obliterative arterial disease (POAD) (clinical symptoms: intermittent claudication or rest pain). The control group consisted of 67 normotensive patients. In 33 subjects of the control group the peripheral circulation was intact, while 34 patients suffered from POAD (clinical symptoms: intermittent claudication or rest pain). The total limb blood flow (LBF) was measured by using venous isotope dilution technique. In hypertensive patients the limb vascular resistance (LVR) was markedly elevated, but the LBF remained in the normal range. In patients suffering from both hypertension and POAD the LVR was pathologically elevated and the LBF markedly diminished. After acute vasodilator therapy the LBF significantly increased, despite the drop in blood pressure owing to the extensive decrease of the LVR. It appears that in hypertension the elevation of the LVR is the most characteristic change of the limb circulation. The elevation of the arterial blood pressure has no favorable effect on the limb circulation, and the LBF compared with the blood pressure is relatively low.