Терапевтический архив (Nov 2003)
Comparative evaluation of cardiac hemodynamics and endothelium-dependent reactive hyperemia in arterial hypertension in those living in high-altitudeand plain areas
Abstract
Aim. To reveal the specific features of cardiac hemodynamics and endothelial function in high-altitude native dwellers with arterial hypertension (AH). Materials and methods. 90 native dwellers from high-altitude and plain areas, who had Stages I and II AH, were examined. To assess cardiac contractility, central and peripheral hemodynamics, the authors used electrocardiography, echocardiography, tetrapolar impedance rheoplethysmography. The functional status of the endothelium was evaluated by the reproduction of endothelium-dependent reactive hypermia in the antebrachial vessels. Results. The patients with Stages I and II AH who live in high-altitude area have been found to have less pronounced peripheral vasocontriction due to the less suppression of pump and contractile functions of the heart. Total peripheral resistance in high-altitude dwellers with Stage II AH is practically similar to that in plain inhabitants with Stage I AH. The extended vasodilator reserve in high-altitude inhabitants with AH is also shown by the data obtained in the reproduction of reactive hyperemia in the antebrachial vessels. A less marked decrease in this vascular reaction in patients with AH who live in high-altitude areas may be due to additional production and/or release of nitric oxide in order to increase the vasodilator reserve in moderate hypoxia. Conclusion. The course of AH in high-altitude dwellers is marked by less suppression of cardiac pump and contractile functions and less peripheral vasoconstriction. This may be accounted for by compensatory activation of endothelial vasodilator mechanisms aimed at preserving adequate tissue perfusion and at optimally providing the body with oxygen in moderate hypoxia.
