Lower tissue factor inhibition in patients with ST segment elevation than in patients with non ST elevation acute myocardial infarction

IntroductionMechanisms to explain the different course of coronary thrombosis between ST elevation myocardial infarction (STEMI) and non-STEMI patients remain poorly defined. We hypothesize, however, that STEMI patients may present lower tissue factor plasma inhibition to partly account for their more persistent coronary thrombotic occlusion.Materials and MethodsTotal (t-TFPI ) and free tissue factor plasma inhibitor (f-TFPI), thrombin-antithrombin complex (TAT), plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor (vWF), and fibrinogen were measured on admission and at 3 and 6 months in patients with a first STEMI (n:69) or non-STEMI (n:60). C reactive protein (CRP) was also measured on admission and at 3 months.ResultsSTEMI patients showed lower admission levels of t-TFPI (p = 0.001), f-TFPI (p = 0.030) and fibrinogen (p = 0.022), and higher vWF levels (p = 0.005) than non-STEMI whereas TAT, PAI and CRP levels were comparable. At 3 and 6 months VWF, t-TFPI, f-TFPI, and TAT levels declined significantly in the 2 groups (p = 0.002) reaching similar values. CRP levels also declined at 3 months (p = 0.002). Moreover, the rate of cardiac mortality, non fatal MI or stroke during a 6 year follow-up were unrelated to admission coagulation parameters.ConclusionsThe lower inhibition of tissue factor and greater endothelial dysfunction in STEMI than in non-STEMI patients may enhance thrombosis at the culprit lesion and adjacent coronary plaques, and hence, account at least in part for their different pathophysiology. This condition, however, is limited to the acute phase.