The Relationship of Blood Viscosity to Coronary Artery Disease

Increases in blood viscosity and its determinants (haematocrit and plasma fibrinogen) have been described in groups of subjects with clinical manifestations of arterial disease (myocardial infarction, angina, claudication). Viscosity factors may also be risk associations in prospective studies. We have studied the relationship of blood viscosity (shear rate 100s^-0), haematocrit and fibrinogen to the extent of coronary artery occlusion in 50 males, aged 30-55, prior to coronary arteriography for chest pain. 26 subjects had significant occlusion (>50 per cent stenosis) of 2 or 3 major coronary arteries: 24 had single vessel disease or normal coronary arteries. 25 healthy controls were also studied. There were no significant differences in age or smoking habits between the three groups: use of beta-adrenergic blockers and plasma lipid levels were comparable in the two arteriography groups. Patients with extensive coronary artery disease had increased levels of viscosity and haematocrit (p<0.005), fibrinogen (p<0. 02) and viscosity corrected for haematocrit (p<0. 05), compared to angiographic or asymptomatic controls.