Effectiveness of heparin in preventing thrombin generation and thrombin activity in patients undergoing coronary intervention

Background Thrombus is important in the pathophysiology of several complica tions of angioplasty, including abrupt closure and restenosis. Levels of pr othrombin fragment F1.2 and fibrinopeptide A reflect thrombin generation an d activity. The effect of angioplasty on levels of these markers is unclear . Methods Patients undergoing either balloon angioplasty (n = 30) or directio nal atherectomy (n = 9) were treated with heparin to maintain an activated clotting time of >300 seconds. Levels of F1.2, fibrinopeptide A, and thromb in-antithrombin complex were measured in the coronary sinus and coronary ar tery before and after intervention. Angiograms were reviewed for lesion mor phologic characteristics and dissection. Results There was no evidence for thrombin generation or increased thrombin activity after angioplasty regardless of lesion morphologic characteristic s, dissection, type of intervention, or blood sampling site. In fact, coron ary sinus concentrations of F1.2 decreased after intervention (median 0.31 nmol/L; 25th percentile 0.26 nmol/L, 75th percentile 0.37 nmol/L) before in tervention to 0.23 nmol/L (25th percentile 0.19 nmol/L, 75th percentile 0.3 4 nmol/L) after intervention (P =.002). Conclusions Angioplasty performed in the presence of adequate heparin inhib ited thrombin even when there was complex lesion morphology or dissection. These data suggest that heparin provides satisfactory thrombin inhibition d uring routine angioplasty.