Nomenclature of Raynaud's phenomenon: a capillary microscopic and hemorheologic study.

Hemorheologic parameters and nailfold capillaries were investigated in 72 patients with ischemic hand phenomena and 25 normal subjects. Red blood cell (RBC) aggregation and plasma viscosity were normal in all groups except in patients with secondary Raynaud's phenomenon; in this group, these parameters were significantly increased (p less than 0.001). The capillary density in the nailfold was significantly lower in patients with secondary Raynaud's phenomenon or acrocyanosis (p less than 0.001). The capillary diameters were slightly increased in patients with primary Raynaud's phenomenon, moderately increased in patients with acrocyanosis (more than twofold), and markedly increased in patients with secondary Raynaud's phenomenon (fourfold to fivefold). Nailfold velocity, before and after cold provocation, was decreased in all patients (p less than 0.001). The findings in this study support the conclusion that patients with primary and secondary Raynaud's phenomenon, acrocyanosis, or asphyxia digitorum can be distinguished by combining hemorheologic observations with morphologic and functional microscopic investigations of the nailfold capillaries. The nomenclature currently employed in our clinic can be used to define these different phenomena.