EVIDENCE AGAINST HYPERCOAGULABILITY IN CORONARY-ARTERY DISEASE

The strong epidemiological association between elevated plasma clottin g factors and coronary artery disease is generally interpreted as evid ence that patients with coronary atherosclerosis are in procoagulant ( hypercoagulable) state. A dynamic global test was used to assess the o verall coagulation status of 761 patients with coronary artery disease scheduled for coronary artery bypass grafting and compared to healthy matched controls (n = 100). Platelet reactivity to shear-stress was s imultaneously measured from identical, non-anticoagulated blood sample s. Contrary to expectation, the overall coagulation in cardiac patient s did not differ significantly from that of controls. Furthermore, the coagulation status of patients bore no relationships to the severity of coronary atherosclerosis. The latter is in contrast with platelet r eactivities, which were significantly increased in patients with great er than or equal to 2 vessel disease as compared with single vessel di sease. The present results do not necessarily conflict with the findin g of elevated plasma clotting factors in cardiac patients. However, th ey do not support the claim that these markers are a reflection of a h ypercoagulable state. Indeed, this study confirms that such patients a re in a prothrombotic state, which is related to enhanced platelet rea ctivities, and not to a prothrombotic imbalance of the coagulation mec hanism.