SERPINE1 and myocardial infarction: tPA (Tissue-type plasminogen activator) converts plasminogen to plasmin, a primary fibrinolytic protease.1 tPA and its inhibitor, PAI-1 (plasminogen activator inhibitor-1), have been detected in thrombi from patients with MI.8 PAI-1 and protease nexin-1 have also been detected in AIS thrombi.14 Variation in fibrinolytic proteins and their inhibitors incorporated in thrombi may impact on resistance to therapeutic thrombolysis.