Fibrinolytic Factors and the Risk of Myocardial Infarction or Sudden Death in Patients With Angina Pectoris

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Abstract
Background Disturbances of the fibrinolytic system that lead to decreased removal of fibrin deposits may be important risk factors for coronary thrombosis. There is as yet no consensus on the prognostic value of fibrinolytic parameters, which may be attributed in part to the choice of confounding variables controlled for. Methods and Results The ECAT study is a prospective multicenter study of 3043 patients with angina pectoris followed for 2 years. Baseline measurements included 10 fibrinolytic variables. The results were analyzed in relation to the subsequent incidence of myocardial infarction or sudden coronary death. They are presented before and after adjustment for clusters of confounding variables that are markers of different mechanisms: insulin resistance (body mass index, triglyceride, and HDL cholesterol), inflammation (fibrinogen and C-reactive protein), and endothelial cell damage (von Willebrand factor). An increased incidence of events was associated with higher baseline concentrations of tissue plasminogen activator (TPA) antigen (P=.0002), plasminogen activator inhibitor-1 (PAI-1) activity (P=.02), and PAI-1 antigen (P=.001). The associations of PAI-1 activity and PAI-1 antigen with risk of events disappeared after adjustment for parameters reflecting insulin resistance but were not affected by other adjustments. TPA antigen was affected to a similar extent by adjustment for parameters reflecting insulin resistance, inflammation, or endothelial cell damage, but the risk association disappeared only after combined adjustments. Conclusions The prognostic role of PAI-1 in predicting coronary events is related principally to insulin resistance, whereas that of TPA antigen could be explained only by its relationship with different mechanisms, including insulin resistance, inflammation, and endothelial cell damage.