Relationship between platelet aggregation and plasma beta-thromboglobulin levels in arterio-vascular and renal diseases.

The incidence of second wave of platelet aggregation induced by a small dose of ADP (1 mumol/l) was compared with plasma levels of beta-thromboglobulin in 81 normal individuals, 34 patients with acute myocardial infarction, 11 patients with acute cerebrovascular disease and 26 patients with renal disease. Platelet hyperaggregability was observed in 7% of normal individuals. Plasma levels of beta-thromboglobulin were higher in normal individuals over 60 years of age (48 vs. 32 micrograms/l). In contrast, hyperaggregability was observed in 79% of patients with acute myocardial infarction and in 64% of those with acute cerebrovascular disease. Median plasma levels of beta-thromboglobulin were also significantly elevated in patients with acute myocardial infarction (82 micrograms/ml) or acute cerebrovascular disease (99 micrograms/l). Levels of beta-thromboglobulin in plasma were significantly higher in those patients who demonstrated hyperaggregability. In patients with renal disease only 12% had signs of hyperaggregability. Nevertheless their plasma levels of beta-thromboglobulin were elevated (76 micrograms/l) and correlated with the serum creatinine values. These investigations indicate that patients with acute myocardial infarction or stroke have hyperreactive platelets and evidence of increased platelet inactivation in the circulation. However, evaluation of increased levels of beta-thromboglobulin requires consideration of renal function.