title: High-shear- and-thrombin-inducible platelet adhesion and aggregation in patients undergoing percutaneous coronary intervention. Effects of unfractionated heparin versus bivalirudin.
abstract: Thrombin-generation and activation of platelets during percutaneous coronary intervention (PCI) play a key role for early thrombotic events. Heparin and bivalirudin are approved anticoagulants for PCI. We examined the specific effects of these anticoagulants on platelet adhesion and aggregation under high shear conditions, and the presence of excess thrombin. To simulate in vivo conditions that may precipitate a bleeding/thrombotic event, we added thrombin in vitro to blood samples from 89 stable patients who had been randomly assigned to receive heparin or bivalirudin for elective PCI and examined thrombin-inducible platelet adhesion and aggregation under high shear conditions. Platelet adhesion increased by 10% of baseline with heparin, but decreased by 20% with bivalirudin (p=0.0047). Thrombin-inducible platelet adhesion and size of aggregates was equally inhibited by heparin and bivalirudin. Thus, under high shear conditions and excessive thrombin generation as they occur in atherosclerotic vascular compartments and acute vascular syndromes, heparin and bivalirudin inhibit thrombin-induced platelet adhesion and aggregation to a similar extent, while they have opposite effects on platelet adhesion in the absence of thrombin.
authors.affiliation: Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Roza Badr
authors.initials: RB
authors.lastname: Eslam
authors.forename: Nina
authors.initials: N
authors.lastname: Reiter
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kaider
authors.forename: Irene M
authors.initials: IM
authors.lastname: Lang
authors.forename: Simon
authors.initials: S
authors.lastname: Panzer
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D000925:Anticoagulants / Q000494:pharmacology; D005260:Female; D006470:Hemorrhage; D006493:Heparin / Q000737:chemistry; D006629:Hirudins / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000737:chemistry; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D011994:Recombinant Proteins / Q000737:chemistry; D033081:Shear Strength; D013917:Thrombin / Q000737:chemistry / Q000378:metabolism; D013927:Thrombosis / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D006629:Hirudins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D006493:Heparin; D013917:Thrombin; C074619:bivalirudin