Characteristics of functional state of arteriolar and venular skin microvessels in patients with essential arterial hypertension

Abstract

The aim of the study was to evaluate the vasomotor activity of skin precapillary arterioles, depending on the condition of blood outflow from the capillary bed in patients with essential arterial hypertension (AH). The study included 30 normotensive subjects (NT) and 63 patients with AH, who were tested with a laser Doppler flowmetry with wavelet analysis of blood flow oscillations on the right forearm and ambulatory blood pressure monitoring (ABPM) on the left shoulder. Antihypertensive therapy was stopped for all patients 14 days prior to the experiment or AH was diagnosed for the first time. The hypertensive patients were divided into 2 groups, depending on the amplitude of the respiratory blood flow oscillations in skin microvessels. The first group included 30 patients without blood outflow violations of the capillary bed (AHVN), the second group consisted of 33 patients with various intensity of functional disorders in venular sector of microvasculature (AHVS). If the value of the amplitude of blood flow oscillations can be related to the tone" definition, then AHVN patients have a significant increase in neurogenic component of vascular tone (p<0.002) and violation of microvessel vasomotor endothelial function (p=0.065) in regard to NT, and AHVS patients to NT have a significant reduction of myogenic component tone of precapillary arterioles (p<0.05). AHVN patients compared to AHVS patients have a higher precapillary arteriolar tone due to endothelial (p<0.01), neurogenic (p<0.01) and myogenic (p<0.01) components of the vascular tone. Despite the lower values of the precapillary arteriolar tone, AHVS patients have higher BP values both at daytime (p<0.0005), and in nocturnal hours (p<0.05), and the functional state of venular sector is connected with nocturnal BP reduction. Obtained results indicate that hypertensive patients can have significant differences in the functional state of microvessels. The assessment of the initial skin microvasculatory regulatory mechanism status could potentially be useful for individual choice of antihypertensive therapy.