Skin capillary blood cell velocity in patients with arterial obliterative disease and polycythaemia: a disturbed reactive hyperaemia response.

Nailfold skin capillary blood cell velocity (CBV) was studied at rest and during post-occlusive reactive hyperaemia after a 1 min arterial occlusion (PRH1) in: (i) both hands of patients with arterial obliterative disease (AOD) of one arm, (ii) patients with polycythaemia, before and after a moderate haemodilution and (iii) healthy controls. CBV was analysed by videophotometric cross-correlation utilizing the different optical densities produced by the passage of erythrocytes, leucocytes and plasma gaps through the monitored capillary. Resting CBV in the patients with unilateral AOD was similar in equivalent fingers of both hands. However, the time to peak (p)CBV during PRH was significantly prolonged in the low-pressure arm as compared to the contralateral arm. pCBV was also delayed in the patients with polycythaemia as compared to the healthy controls. This delay was not affected by the replacement of 500-750 ml of blood with the same amount of a 6% Dextran 70 solution. The mean capillary blood cell velocity during rest (rCBV) did not differ between controls and patients before or after the haemodilution. The prolonged time to pCBV in the polycythaemic patients may be attributed to increased blood viscosity that is presumably not significantly influenced by a moderate haemodilution using Dextran 70. The marked delay to pCBV observed distal to the arterial obstruction in patients with AOD probably is an effect of the lower arterial pressure, presumably involving an alteration of vascular smooth muscle function.