Arteriolar resistance and hemorheological disorders related to Raynaud's phenomenon

The functional condition of resistance arteries in human hands was monitored with a noninvasive test. Blood flow velocity changes (Doppler flow meter) were monitored in the radial artery before and after a 1-min stop flow in the hand under conditions of stable systemic arterial pressure. In addition, the most significant parameter of hemorheological disorders in microcirculation, RBC aggregability, was investigated in the same patients' blood samples. The muscular tone of the resistance arteries was found to be a mean of 35% higher during Raynaud's phenomenon than in the healthy controls tested. The raised vascular tone was not related to the patients' age and had a pronounced tendency to rise with disease duration. RBC aggregability was a mean of 4% higher in the patients than in the healthy controls, and the difference was not reliable. We concluded that, among principal pathogenic factors which might cause deficiency of the blood supply to fingers, it is the enhanced tone of resistance arteries that is primarily responsible for the development of Raynaud's phenomenon, while hemorheological disorders are not, or are considerably less, involved in the development of the principal symptom of the disease, deficient blood supply to the fingers.