INCREASED MONOCYTE TISSUE FACTOR EXPRESSION IN CORONARY-DISEASE

Objective-To investigate whether monocyte expression of tissue factor is increased in patients with acute coronary syndromes and chronic sta ble angina. Design-Cross sectional study of monocyte tissue factor exp ression in patients with ischaemic heart disease and control subjects. Background-Unstable angina and myocardial infarction are associated w ith enhanced mononuclear cell procoagulant activity. Procoagulant acti vity of blood monocytes is principally mediated by tissue factor expre ssion. Tissue factor initiates the coagulation cascade, and monocyte t issue factor expression may therefore be increased in these syndromes. Methods-Monocyte tissue factor expression was measured cytometrically in whole blood flow using a polyclonal rabbit antihuman tissue factor antibody. Patients-30 patients with acute myocardial infarction, 17 w ith unstable angina, 13 with chronic stable angina, and 11 normal cont rol subjects. Results-Increased proportions of monocytes expressing ti ssue factor (> 2.5%) were found in none of 11 (0%) normal subjects, fi ve of 13 (38%) patients with stable angina, 11 of 17 (64%) patients wi th unstable angina, and 16 of 30 (53%) patients with myocardial infarc tion (2P = 0.006). Blood from all subjects showed similar monocyte tis sue factor expression (46.1 (15.1)%) after lipopolysaccharide stimulat ion. Conclusion-Hypercoagulability associated with acute myocardial in farction, unstable angina, and chronic stable angina may be induced by tissue factor expressed on circulating monocytes.