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[Vascular damage in arterial hypertension: its noninvasive assessment]
Insights
Arterial hypertension damages blood vessels, impacting cardiovascular health. Non-invasive ultrasound and plethysmography assess vascular damage, revealing increased resistance and reduced perfusion proportional to blood pressure severity.
Area of Science:
- Cardiovascular Medicine
- Vascular Biology
- Diagnostic Imaging
Background:
- Arterial hypertension is a primary risk factor for atherosclerotic and cardiovascular diseases.
- Hypertension directly causes structural damage to arteries and arterioles.
- Advanced non-invasive methods are crucial for evaluating vascular damage.
Purpose of the Study:
- To review current non-invasive diagnostic tools for assessing vascular damage in arterial hypertension.
- To highlight the role of ultrasonography and plethysmography in evaluating arterial and arteriolar function.
- To discuss the clinical utility of these methods in hypertension management and treatment evaluation.
Main Methods:
- High-resolution echotomography and Doppler ultrasonography for evaluating large and small arteries, including plaque characterization and hemodynamic assessment.
- Pulsed wave velocity and aortic distensibility measurements for assessing arterial compliance of great vessels.
- Strain-gauge plethysmography, laser Doppler, and capillaroscopy for studying small vessel function and cutaneous microcirculation.
Main Results:
- Ultrasonographic methods provide detailed morphological and hemodynamic data comparable to invasive techniques.
- Decreased arterial compliance is proportional to the severity of blood pressure.
- Minimal vascular resistances increase with rising blood pressure across all hypertension stages, and cutaneous microcirculation is reduced.
Conclusions:
- Non-invasive ultrasonographic and plethysmographic techniques are valuable for assessing vascular damage in hypertension.
- These methods demonstrate a direct correlation between hypertension severity and vascular structural/functional alterations.
- Diagnostic tools aid in monitoring antihypertensive treatment efficacy on vascular health.
Abstract:
Arterial hypertension is a definite risk factor for the atherosclerotic disease and thus has a primary role in the genesis of cardiovascular diseases, but it acts also though a direct structural damage of great and small arteries and arterioles. Up to date, clinical research and technological advancements have made possible the development of instruments and methods for the evaluation of the vascular damage. Ultrasonographic methods are now the better non invasive tools for the study of arterial diseases, allowing a definition power comparable to angiography, and giving useful data on characters and composition of plaques, also minimal, at the level of the arterial district of lower limbs, epiaortic, renal, and abdominal vessels. These methods allow the study of the vascular lesion under the hemodynamic (CW or pulsed Doppler with spectral signal analysis) and the morphological profile (high resolution echotomography) or both echo-Doppler duplex scanning or color flow imaging). Arterial compliance of great vessels can be studied through the Doppler evaluation of pulsed wave velocity along the arterial tree. Other useful parameters are the aortic distensibility (ratio between % change in arterial volume and blood pressure), the elastic module, the index of arterial rigidity and the aortic index (ratio between pulse pressure and stroke volume). By using this latter parameter we demonstrated a significant decrease of arterial compliance that is proportional to the severity of blood pressure values. Small vessels may be studied through strain-gauge plethysmography, that allows to obtain the regional blood flows at the hand and forearm (skin circulation) and the calf (muscular circulation) both in basal conditions and after ischaemic stimulus. From the ratio between mean arterial pressure and post-ischemic blood flow it is possible to obtain minimal vascular resistances, expression of the maximal vasodilatation capacity in the arteriolar bed. With this method we showed that minimal vascular resistances increase proportionally with the increase of blood pressure in borderline hypertensives, in mild, moderate and severe stable arterial hypertension and in hypertension of the aged. The cutaneous microcirculation may be studied also by laser Doppler and capillaroscopy, that show a reduced capillary perfusion in hypertension. Clinically, these diagnostic tools are also extremely useful for studying the effects of antihypertensive treatment on structure and function of arterial vessels, as it seems that some drugs are able to counteract the structural alterations related to hypertension.