Local heat stress and skin blood flowmotion in subjects with familial predisposition or newly diagnosed hypertension

Abstract

Objective. The aim of the study was to investigate the skin microcirculation blood flow and flowmotion response to heat stress in normotensive subjects with familial predisposition to hypertension and in hypertensive patients. Methods. Normotensives without [NT(-)] or with [NT(+)] familial predisposition and subjects with newly diagnosed hypertension (HT) were studied. Clinic blood pressure (BP) measurements and ambulatory BP monitoring as well as laboratory assessments were performed. Resting (RF), heat (HF) and maximal heat (MHF) blood flows were measured using PeriFlux laser Doppler flowmetry (LDF) and expressed as absolute units (AU) and as index of cutaneous vascular conductance (CVC). Spectral analysis of the skin LDF signal was performed by means of the Perisoft dedicated software. KruskallWallis analysis of variance, χ2 statistic and multivariate reverse regression analysis were used for calculation. Results. The studied population consisted of 70 persons (mean age 36.1±10.3 years, 44.3% women): 17 NT(-), 22 NT() and 31 HT, age and gender matched. Higher values of body mass index (BMI), and insulin, glucose and triglyceride levels were observed in HT than in NT groups. RF, HF and MHF were similar in all study groups, but CVC of maximal heat flow differed (p0.02); in particular, lower values were observed in the HT than in NT(-) group (p0.01). The study groups differed with regard to total power (p0.01) and myogenic (p0.03) origin flowmotion with the lowest values in the NT(+) group. BMI and night BP characteristics were strong predictors of reduction of CVC, MHF and myogenic origin flowmotion. Conclusion. Skin microcirculation response to local heat stress is altered in hypertensive patients with decrease in maximal heat CVC values. Moreover, normotensive subjects with familial predisposition to hypertension are characterized by diminished myogenic origin of skin blood flowmotion. © 2010 Scandinavian Foundation for Cardiovascular Research.