Blood rheology and platelet function were studied serially in 23 patients with unstable angina compared to 70 healthy controls. On admission, the angina patients had raised blood viscosity at, any shear rate (m ± SEM) at = 0.94 sec−1: 17.3 ± 0.5 vs 14.7 ± 0.2 mPas; p<.001), plasma viscosity (1.32 ± 0.02 vs 1.22 ± 0.01 cSt; p<.001), and erythrocyte aggregation index (16.2 ± 0.7 vs 14.6 ± 0.4; p<.01). Plasma fibrinogen, plasma protein concentration, hematocrit and erythrocyte filterability were not different from those of the control group. ADP platelet aggregation in vitro was normal, but plasma levels of β-thromboglobulin (65.3 ± 9.5 vs 31.1 ± 1.3 ng/ml; p<.001), of platelet factor 4 (24.7 ± 4.5 vs 6.6 ± 0.6 ng/ml; p<.001) and of platelet malonyldialdehyde (5.6 ± 0.5 vs 5.0 ± 0.2 nmol/109 platelets; p<.05) were significantly higher. The hemorheological and platelet abnormalities observed on admission in the patients who later developed complications (that is, who had infarctions or a recurrence of angina, or who died) were similar to those observed in the patients whose progress was good. There was no relation between the degree of hemorheological disturbances, and platelet dysfunction and the number of attacks of angina. Thesure results demonstrate the existence of a syndrome of blood hyperviscosity and platelet dysfunction in unstable angina. These disturbances did not seem to be related to the clinical outcome of patients or to the severity of angina.
