Plasma viscosity, fibrinogen and haematocrit in the course of unstable angina.

Plasma viscosity, fibrinogen and haematocrit were measured in 80 patients with unstable angina on the 1st, 2nd and 5th day of hospitalization. In the group of patients who developed acute myocardial infarction (AMI) during hospitalization (20 patients), plasma viscosity was elevated during the entire observation period (1.69 +/- 0.05 cp, normal range 1.38-1.48 cp), while in patients who did not develop AMI, plasma viscosity was only mildly elevated (1.59 +/- 0.05 cp, P less than 0.001 vs the group who developed AMI) and tended to normalize towards the 5th day of hospitalization. Fibrinogen and haematocrit showed similar variations between the two groups. In a group of 20 patients who received heparin, the studied parameters were similar to the group who did not develop AMI. The importance of haemorheological factors in the clinical course of unstable angina is thus emphasized.