Abstract-A reduction in the density of capillaries (rarefaction) is known to occur in many tissues in patients with essential hypertension. This rarefaction may play a role in increasing peripheral resistance. However, the mechanism underlying this capillary rarefaction is not understood. The aim of this study was to assess the extent of structural versus functional capillary rarefaction in the skin of dorsum of fingers in essential hypertension. The capillary microcirculation was examined with video microscopy before and after maximizing the number of perfused capillaries by venous congestion. The study group comprised 17 patients with essential hypertension (mean supine blood pressure, 155/96 mm Hg) and 17 closely matched normotensive controls (mean blood pressure, 127/77 mm Hg). We used intravital video microscopy with an epi-illuminated microscope to examine the skin of the dorsum of left middle phalanx before and after venous congestion at 60 mm Hg for 2 minutes. A significantly lower mean capillary density occurred at baseline in hypertensive subjects versus normotensive subjects. With venous occlusion, capillary density increased significantly in both groups; however, maximal capillary density remained significantly lower in the hypertensive subjects than in the normotensive subjects. The study strongly suggests that much of the reduction in capillary density in the hypertensive subjects is caused by structural (anatomic) absence of capillaries rather than functional nonperfusion. (Hypertension. 1999;33:998-1001.)

Abstract-We recently showed that rarefaction of skin capillaries in the dorsum of the fingers of patients with essential hypertension is due to the structural (anatomic) absence of capillaries rather than functional nonperfusion. It is not known whether this rarefaction is primary (ie, antedates the onset of hypertension) or secondary (ie, as a consequence of sustained and prolonged elevation of blood pressure [BP]). The aim of the present investigation was to study skin capillary density in a group of patients with mild borderline hypertension to assess whether rarefaction antedates the onset of sustained elevation of BP. The study group included 18 patients with mild borderline hypertension (mean supine BP, 136/83 mm Hg), 32 normotensive controls (mean BP, 126/77 mm Hg), and 45 patients with established essential hypertension (mean BP, 156/98 mm Hg). The skin of the dorsum of the fingers was examined by intravital capillary videomicroscopy before and after venous congestion at 60 mm Hg for 2 minutes. Patients with borderline essential hypertension had the lowest resting capillary density when compared with normotensive controls and patients with established hypertension. Maximal capillary density with venous congestion in the borderline group remained the lowest. The study confirmed that patients with borderline essential hypertension 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. (Hypertension. 1999;34:655-658.)

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AIMSTo undertake a systematic review and meta-analysis of randomized controlled trials concerned with the impact of community pharmacist-led interventions on blood pressure control in patients with hypertension.