Changes in protease inhibitors after acute myocardial infarction.

Plasma levels of fibrinogen, alpha1-antitrypsin, alpha2-macroglobulin, antithrombin III, and C1 inactivator were measured serially for 10 days in 11 patients after acute myocardial infarction. Both fibrinogen and alpha1-antitrypsin rose markedly to reach peak levels 5-7 days after infarction while C1 inactivator levels rose slowly with the highest observed mean level on the 10th postinfarction day. Neither antithrombin III nor alpha2-macroglobulin changed significantly after myocardial infarction. No relationship between C1 inactivator levels and either fibrinogen or alpha1-antitrypsin was found in a study of 30 patients with a variety of disorders while fibrinogen and alpha1-antitrypsin levels were significantly correlated.