Our aim was to assess whether the vessel wall trauma induced by balloon inflation during successful elective PTCA results in activation of coagulation and fibrinolysis detectable in circulating blood. In the pilot group (10 patients), when blood was collected under heparinization with adequate anti-Factor Xa activity, catheter-induced thrombin generation was not detected and results obtained from local coronary arterial versus systemic samples did not differ. Locally, von Willebrand factor antigen increased from 73.5 +/- 8.8% to 77.8 +/- 13.1% (p < 0.05) at 5 min after PTCA. In the study group with its 21 patients having adequate heparinization fibrinogen decreased when blood was collected from aorta 15 min after PTCA. In 30% of the patients having the largest calculated area of vessel damage, thrombin-antithrombin III (TAT) complex and prothrombin fragments (F1+2) spiked by at least 25% during PTCA. In all patients the mean TAT values did not increase, but F1+2 (from 0.56 +/- 0.36 to 0.63 +/- 0.39 nmol/l, mean +/- SD, p < 0.05) and D-dimer (from 268 +/- 37 to 325 +/- 45 ng/ml, p < 0.05) rose between 15 to 30 min after PTCA. In conclusion, in every third patient thrombin generation occurs after successful elective PTCA, implying a need for a tighter control than heparin provides.