The influence of gender differences of skin microhemodynamics parameters assessed in heating and occlusion tests

   Introduction. The results of studies devoted to the influence of biological sex on microhemodynamic parameters are ambiguous. Today no studies of sex-specific microhemodynamics evaluated by the new incoherent optical fluctuation flowmetry method (IOFF) have been reported.   Objective – to investigate the sex-specific differences of microhemodynamics assessed by the IOFF method in healthy volunteers.   Materials and Methods. 27 healthy volunteers (10 men and 17 women) were included in the study. The groups were comparable by sex, age, and main clinical parameters. Perfusion was measured by the IOFF method. Parameters were evaluated while performing an occlusion test on the hand and a local heating test on the dorsum of the foot and the toe. Microcirculation reactivity was calculated as a relative increase of perfusion response to the vasodilation stimulus.   Results. Women had significantly lower median baseline perfusion than men on the hand and on the dorsum of the foot (hand: 10 [6; 13] PU vs. 15 [10; 19] PU, p = 0.035; foot: 0.78 [0.68; 0.97] PU vs. 1.13 [0.99; 1.29] PU, p = 0.003). Women were demonstrated to have significantly higher reactivity response to thermal and occlusive stimuli than men (p < 0.05). Thus, at the third minute of heating, women had perfusion increased 5.39 [4.32; 6.64] times and men had 3.47 [3.13; 4.65] times (p = 0.018); after the release of the occlusion women had perfusion increased 1.93 [1.37; 3.02] times and men had 1.14 [1.01; 1.74] times (p = 0.011).   Conclusion. Healthy women had been shown to have higher reactivity of microhemodynamics than men. A lower cardiovascular risk women have compared to men could be caused by sex-specific features of endothelium function.