To determine whether activation of platelets and coagulation is present in patients with coronary artery disease, plasma levels of platelet factor 4 (PF4), β-thromboglobulin (βTG), and fibrinopeptide A (FPA) were measured by radioimmunoassay in patients subjected to coronary angiography. The patients were divided into those with normal coronary angiograms (Group I, n = 14), those with coronary artery disease (> 70% narrowing) but no previous myocardial infarction (Group II, n = 32), and those with coronary artery disease and documented previous myocardial infarction (Group III, n = 36). The three groups did not differ in sex, incidence of hypertension or diabetes, serum cholesterol, HDL cholesterol, BUN or platelet count. Geometric mean values for the three groups were FPA: 0.77, 0.81 and 1.01 pmol/ml respectively, βTG: 22.7, 21.6 and 33.2 ng/ml respectively, and PF4: 5.7, 5.8 and 8.3 ng/ml respectively. When the data were tested by analysis of variance, significant elevations of βTG (p< .01) and PF4 (p< .05) were found in Group III but there were no other significant changes. When Group III was subdivided into patients with and without ventricular aneurysm, BTG and FPA levels were found to be higher in patients with aneurysm than without: βTG 45.9 vs. 30.3 ng/ml and FPA 1.64 vs. 0.88 pmol/ml (p< .05 for each). βTG levels were also higher in patients with congestive heart failure (p< .01) and showed an inverse correlation with left ventricular ejection fraction (p< .05) and a direct correlation with the extent of left ventricular asynergy (p< .01). In conclusion, elevations in βTG and PF4 were associated with previous infarction, not with coronary artery disease. These changes are thought to reflect platelet reaction with the damaged ventricular wall. Elevations in FPA were seen only in patients with ventricular aneurysm and may reflect mural thrombus within the aneurysm.
Platelet aggregation and fibrin clot structure in patients with coronary artery disease and previous myocardial infarction
