Hypofibrinolysis in atrial fibrillation

Background There is a high incidence of systemic embolism in patients with chronic atrial fibrillation. A hypercoagulable state has been demonstrated, but the fibrinolytic system is rarely studied. Methods Plasma levers of modified antithrombin III (ATM), tissue plasminoge n activator (TPA), its inhibitor (PAI-1 ), TPA-PAI-1 complexes and plasmin- antiplasmin complexes (PAP), D-dimer, and fibrinogen were measured in plasm a from 36 patients with chronic atrial fibrillation. Fifteen patients had r heumatic mitral stenosis and 21 had nonrheumatic atrial fibrillation. Level s were compared with those found in the plasma of 20 healthy subjects. Tran sthoracic echocardiographic studies were done. Results Patients with atrial fibrillation had higher plasma levels of ATM, D-dimer, PAI-1, and TPA-PAI-1 complexes than controls (P < .001). The rheum atic atrial fibrillation group also showed elevated levels of fibrinogen (P < .05). No significant differences were found in TPA and PAP. There were n o differences between rheumatic and nonrheumatic atrial fibrillation. Conclusions Atrial fibrillation shows a hypofibrinolytic state caused by el evated PAI-1 levels with no increase in PAP complex concentration. Elevated plasma D-dimer levels suggest increased intravascular thrombogenesis. This may contribute to increased risk of thrombosis.