In this multicenter, collaborative, prospective study, patients hospitalized with a myocardial infarction were enrolled from ten geographically dispersed centers. Five thrombogenic- related blood factors were quantitated, and formed the centerpiece of this study: 1) lipoprotein(a) [Lp(a)] - a quantitative genetic factor that contains apolipoprotein B, has a structural homology to plasminogen, interferes with intrinsic thrombolytic activity, and represents a crossover link in the thrombogenesis/atherogenesis hypothesis; 2) soluble fibrin - a system indicator of coagulation activity in the ongoing conversion of fibrinogen to insoluble fibrin strands; 3) plasminogen activator inhibitor-1 (PAI-1) - an important regulator of the fibrinolytic system, it interferes with intrinsic t-PA activity; 4) coagulation Factor VII -high levels lead to increased thrombogenesis and have been associated with an increased risk of ischemic heart disease; and- 5) von Willebrand factor - it binds to platelet glycoproteins, contributes to local thrombus formation, and it is elevated in patients at increased risk of coronary thrombosis.