title: Effects of non-vitamin K antagonist oral anticoagulants on fibrin clot and whole blood clot formation, integrity and thrombolysis in patients with atrial fibrillation.
abstract: Non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin and heparins in several clinical situations. With varying modes of action, the effects of NOACs on thrombus formation, integrity, and lysis is unknown. To determine whether two techniques of thrombelastography (TEG) and a micro-plate assay (MPA) provide novel data on thrombus formation, integrity and lysis in those taking a NOACs compared to warfarin and a control group taking aspirin. We assessed thrombogenesis, clot integrity and fibrinolysis in blood (TEG) and plasma (MPA) from 182 atrial fibrillation patients-50 on aspirin, 50 on warfarin, and 82 on a NOAC (17 apixaban, 19 dabigatran and 46 rivaroxaban). Eleven of 16 TEG indices and 4 of 5 MPA indices differed (p ≤ 0.01) between those on aspirin, warfarin or a NOAC. Three TEG indices and 4 MPA indices differed (p < 0.01) between the NOACs. Time to initiation of clot formation was most rapid on apixaban, then rivaroxaban and slowest on dabigatran. The rate of clot formation was most rapid on dabigatran, then apixaban, and slowest on rivaroxaban. Clot density was greatest on rivaroxaban, then apixaban, but weakest on dabigatran. The rate of clot dissolution was most rapid in apixaban, then dabigatran, and slowest on rivaroxaban. The TEG and MPA identify major differences in thrombogenesis and fibrinolysis in different NOACs. These techniques may have value in investigating the effects of these drugs on haemostasis in a clinical setting, and in identifying those in need of targeted therapy.
authors.affiliation: Institute for Cardiovascular Sciences, City Hospital, University of Birmingham, Dudley Road, Birmingham, B18 7QH, UK.
authors.forename: Yee Cheng
authors.initials: YC
authors.lastname: Lau
authors.affiliation: Institute for Cardiovascular Sciences, City Hospital, University of Birmingham, Dudley Road, Birmingham, B18 7QH, UK.|Cardiovascular Department, The Second Affiliated Hospital of Nanchang University, Nanchang, China.
authors.forename: Qinmei
authors.initials: Q
authors.lastname: Xiong
authors.affiliation: Institute for Cardiovascular Sciences, City Hospital, University of Birmingham, Dudley Road, Birmingham, B18 7QH, UK.
authors.forename: Eduard
authors.initials: E
authors.lastname: Shantsila
authors.affiliation: Institute for Cardiovascular Sciences, City Hospital, University of Birmingham, Dudley Road, Birmingham, B18 7QH, UK.
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
authors.affiliation: Institute for Cardiovascular Sciences, City Hospital, University of Birmingham, Dudley Road, Birmingham, B18 7QH, UK. andrew.blann@hotmail.com.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Blann
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D001281:Atrial Fibrillation / Q000097:blood / Q000188:drug therapy; D001777:Blood Coagulation / Q000187:drug effects*; D005337:Fibrin / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D015912:Thrombolytic Therapy; D014812:Vitamin K
chemical_list: D000925:Anticoagulants; D014812:Vitamin K; D005337:Fibrin
keywords: Atrial fibrillation; Fibrinolysis; NOAC; Thrombelastograph; Thrombosis