Abnormal blood rheology in Raynaud’s phenomenon

Abstract

Blood rheology measurements (blood viscosity, plasma viscosity, and erythrocyte deformability) were made at 15°C and 37°C in 16 patients with Raynaud’s phenomenon (11 secondary) compared with 16 healthy matched controls. At both temperatures the patients showed a significant reduction in filterability of washed erythrocytes through pores of 3 µm and 5 µm diameter and an increase in plasma viscosity. The rheological abnormality was greater at 15°C than 37°C in both patients and controls. A cold provocation test (immersion of the hand for 5 min in water at 4°C) had no effect on the deformability of erythrocytes taken from the cubital fossa. The temperature dependency of erythrocyte and plasma rheology, although not specific for Raynaud’s phenomenon, will contribute to impaired microvascular perfusion in cold extremities.