Objective: To asses endothelial function and variables of fibrinolysis and coagulation in smokers compared to healthy controls. Methods: Flow-associated dilation as a marker for peripheral endothelial function and intima media thickness as a marker for early morphologic vascular changes were measured in otherwise healthy smokers (n = 30, 16 males and 14 females, age: 40.6 ± 11.3 years, body mass index 24.9 ± 3.7 kg/m²) and non-smoking controls matched for age and sex using high-resolution ultrasound. Variables of the coagulation system (thrombin-antithrombin III complex, fibrinogen) and fibrinolysis (tissue-plasminogen activator, plasmin-α₂-antiplasmin complex) were determined by ELISA and plasminogen activator inhibitor activity by means of a chromogenic substrate test. Results: Compared to the non-smoking controls, flow-associated vasodilatation was significantly reduced (6.9 ± 4.4 vs. 10.5 ± 6.2%, p = 0.01) and intima media thickness tended to be increased (0.58 ± 0.12 vs. 0.52 ± 0.14 mm, p = 0.08) in smokers. The thrombin-antithrombin III complex, fibrinogen, plasmin-α₂-antiplasmin complex, tissue-plasminogen activator and plasminogen activator inhibitor activity did not differ between smokers and controls. Conclusion: Our data indicate that peripheral endothelial dysfunction is common in smokers even without major alterations in molecular markers of the coagulation and fibrinolysis system.

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