Evaluation of the dilator capacity of skin blood vessels of hypertensive patients by laser Doppler flowmetry.

Knowledge of regional circulation in the skin of hypertensive patients is largely incomplete. We examined the vasodilator capacity of skin blood vessels in the foot in 20 hypertensives and in 20 age- and sex-matched normal control subjects. Vasodilator capacity was assessed by measuring skin blood flow (laser doppler flowmetry) and cutaneous vascular resistance at rest and at the peak of the postocclusive reactive hyperemia response. Skin blood flow was higher in hypertensive patients than in controls at rest (69.4 +/- 23.6 vs. 44.2 +/- 17.5 mV; P less than 0.003), but did not differ significantly after reactive hyperemia (89.2 +/- 23.5 vs 88.2 +/- 25.4 mV; N.S.). Calculated cutaneous vascular resistance was higher in controls at rest (2.99 +/- 1.06 vs 2.22 +/- 0.81 a.u.; P less than 0.3), but lower after reactive hyperemia (1.43 +/- 0.44 vs 1.64 +/- 0.43 a.u.; N.S.). Laser Doppler flowmetry is a technique suitable for studying the alterations in cutaneous microcirculation induced by hypertension. These data are compatible with structural changes in the vascular wall of hypertensive patients.