Background and method In order to evaluate whether arterial hypertension (AH) affects skin microcirculation, 46 newly diagnosed, never-treated, hypertensive patients and 20 healthy normotensive controls underwent a forearm skin postocclusive reactive hyperaemia (PORH) test, using laser-Doppler flowmetry (LDF). Their resting skin blood flow oscillations (SBFOs) were also investigated using wavelet spectral analyses of skin LDF tracings within six frequency subintervals in the 0.005-2 Hz spectral range. To evaluate whether antihypertensive treatment affects skin microcirculation, the same measurements were repeated in 22 of the recruited hypertensive patients after 8+/-2 weeks of antihypertensive treatment.

Results Significantly reduced PORH, together with significantly higher spectral amplitudes within the majority of the investigated SBFO subintervals, was found in untreated hypertensive patients compared with controls. In the 22 hypertensive patients who completed the follow-up, there was a significant increase in PORH after antihypertensive treatment compared with before (357+/-178 vs. 284+/-214%, respectively, P<0.05). Following antihypertensive treatment, the same 22 hypertensive patients did not differ significantly from controls either in PORH or in the majority of the investigated SBFO frequency subintervals.

Conclusion This study showed reduced skin vasoreactivity in the hypertensive patients, confirming that antihypertensive treatment negatively affects skin microcirculation. The short period of efficacious antihypertensive treatment resulted in normalization of skin vasoreactivity in hypertensive patients who completed the follow-up, suggesting that antihypertensive treatment affects positively skin microcirculation in AH. The SBFO increase in untreated hypertensive patients, and its almost complete normalization in treated hypertensive patients, suggests that SBFO enhancement in untreated hypertensive patients could be an adaptive reversible response to AH.