Relationships between blood rheology and transcutaneous oxygen pressure in peripheral occlusive arterial disease

Abstract

Increased blood viscosity has been shown to experimentally reduce blood flow. In lower limb ischaemia, haemorheologic abnormalities have been repeatedly described but their pathophysiologic importance remains unclear. In this study, we investigated the possible influence of blood rheology on oxygen transfer (as measured by transcutaneous oxygen pressure: TcPO₂) in 121 nondiabetic patients suffering from P.O.A.D. (age: 46–91 year-old, 88 men and 33 women) with Leriche and Fontaine stage: II (n=61); III (n=35); IV (n=25), compared to 39 controls. Blood viscosity was higher (p<0.001) in patients, due to increased plasma viscosity (p<0.01) and red cell rigidity which was significantly (p<0.01) higher. Red blood cell aggregation (Myrenne aggregometer) was significantly higher (p<0.05) in P.O.A.D. and was negatively correlated with TcPO₂ after one minute standing and after three minutes standing (p<0.001). In stage III, patients TcPO₂ is negatively correlated with haematocrit/viscosity ratio (a proposed index of the influence of blood rheology on oxygen transfer; p<0.01). The correlation between TcPO₂ and red blood cell rigidity (Tk index; p<0.01) suggest that blood rheology may influence oxygen transfer to tissues in patients with P.O.A.D.. The factors of blood viscosity which may be involved in worsening the ischaemic process may be (a) red cell rigidity (in stage III); (b) red cell aggregation (in the whole sample of patients).