Rarefaction of skin capillaries in borderline essential hypertension suggests an early structural abnormality

We recently showed that rarefaction of skin capillaries in;: the dorsum of the fingers of patients with essential hypertension is due to the structura l (anatomic) absence of capillaries: rather than functional nonperfusion. I t is not known whether this rarefaction is primary (ie, antedates the onset of hypertension) or secondary (ie, as a consequence of sustained and prolo nged elevation of blood pressure [BP]). The aim of the present investigatio n was to study skin capillary density in a group of patients with mild bord erline hypertension to assess whether rarefaction antedates the onset of su stained elevation of BP. The study group included 18 patients with mild bor derline hypertension (mean supine BP, 136/83 mm Hg), 32 normotensive contro ls (mean BP, 126/77 mm Hg), and 45 patients with established essential hype rtension (mean BP, 156/98 mm HE) The skin of the dorsum of the fingers was examined by intravital capillary videomicroscopy before and after venous co ngestion at 60 mm Hg for 2 minutes. Patients with borderline essential hype rtension had the lowest resting capillary density when compared with normot ensive controls and patients with established hypertension. Maximal capilla ry density with venous congestion in the borderline group remained the lowe st. The study confirmed that patients with borderline essential hypertensio n have skin capillary densities that are equally low as or even lower than patients with established hypertension. Both groups had significantly lower capillary densities than normal controls. One explanation for the results is that capillary rarefaction may be due to an early structural abnormality in essential hypertension.