Increased fibrinolytic activity in the intima of atheromatous coronary arteries: protection at a price

Abstract

Objective: The aim was to quantify and compare the fibrinolytic activity of normal blood vessels (saphenous vein, internal mammary artery, and aorta) and atheromatous arteries (coronary endarterectomy specimens). Methods: Fibrinolytic activity was measured by fibrin plate and colorimetric assays on fresh samples of coronary endarterectomy core, internal mammary artery, human aorta, and saphenous vein from patients undergoing coronary artery bypass surgery. Results: Fibrinolytic activity on fibrin plates ranked in the order endarterectomy cores > internal mammary artery > saphenous vein. The increased activity of endarterectomy cores was associated with an increased content of extractable tissue plasminogen activator and was suppressed by monoclonal antibody to tissue plasmogen activator. Paired comparisons of tissues from the same patients confirmed this increased activity in endarterectomy specimens relative to normal artery or vein. Urokinase activity was also increased in some endarterectomy specimens, but was more variable than tissue plasmogen activator. Conclusions: The increased fibrinolytic activity of endarterectomy cores may help preserve patency in atheromatous vessels, but at the possible price of increased intimal instability and fibrous proliferation. Cardiovascular Research 1993;27:882-885