Function of the precapillary vessels in peripheral vascular disease.

This article reviews the present knowledge of vasomotion in skin capillaries of patients with peripheral vascular disease, in particular Raynaud's disease and acrocyanosis. The data are based on measurements of red blood-cell velocity and of fluorescent-dye distribution in capillary areas obtained by videomicroscopy in combination with videodensitometric evaluation. Normally, adjacent skin capillaries exhibit similar flow patterns and are filled at the same time after i.v. Na-fluorescein injection, whereas in acrocyanosis, pathological vasomotion occurs frequently (different flow patterns in adjacent capillaries, delayed filling of single capillaries or capillary groups). Inhomogeneous perfusion is also common in microangiopathy caused by scleroderma. Hypersensitivity to a standardized cold stimulus is the main feature of primary Raynaud's disease.