title: Effect of renal function on whole blood and fibrin clot formation in atrial fibrillation patients on warfarin.
abstract: OBJECTIVE
  Atrial fibrillation (AF) brings a risk of thrombosis, requiring oral coagulation, and is associated with renal impairment. The two processes may be linked, as altered fibrin clot structure is present in end-stage renal failure. We hypothesised that progressively deteriorating renal function is linked to altered whole blood and fibrin clot properties and fibrinolysis.
  
  
  METHODS
  Thrombogenesis and fibrinolysis in 200 warfarinised AF patients was assessed by thromboelastography (TEG), a micro-plate assay (MPA) and the international normalized ratio (INR). Renal function was determined by creatinine clearance and two versions of the estimated glomerular filtration rate (eGFR).
  
  
  RESULTS
  Two TEG indices independently reflecting thrombogenesis were linked to creatinine clearance (p < 0.01), whilst a third, reflecting clot strength, was linked to the eGFR (p < 0.001). MPA indices of thrombogenesis and clot density (p < 0.001), and an index of fibrinolysis (p < 0.001) were linked to the eGFR. The time for 50% of the fibrin clot to lyse was linked to creatinine clearance (p = 0.001). The INR was unrelated to any renal function index, and the CHA2DS2VASc score was unrelated to any index.
  
  
  CONCLUSIONS
  In warfarinised AF patients, renal function is linked to whole blood clot and fibrin clot formation, structure and dissolution, but has no effect on the INR. Key messages Despite oral anticoagulation, patients with atrial fibrillation (AF) still suffer from stroke and venous thromboembolism. The effect of renal function in warfarinised patients with AF is unknown and may account for excess thrombosis and/or haemorrhage. Using two different laboratory methods, our data point to an effect of renal function on clot structure and function that is independent of an effect of warfarin.
authors.affiliation: a University of Birmingham Institute of Cardiovascular Sciences, City Hospital , Birmingham , UK ;
authors.forename: Yee Cheng
authors.initials: YC
authors.lastname: Lau
authors.affiliation: b Cardiovascular Department , The Second Affiliated Hospital of Nanchang University , Nanchang , Jiangxi , PR China.
authors.forename: Qinmei
authors.initials: Q
authors.lastname: Xiong
authors.affiliation: a University of Birmingham Institute of Cardiovascular Sciences, City Hospital , Birmingham , UK ;
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
authors.affiliation: a University of Birmingham Institute of Cardiovascular Sciences, City Hospital , Birmingham , UK ;
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Blann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000494:pharmacology / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests; D005260:Female; D005337:Fibrin / Q000378:metabolism; D005342:Fibrinolysis / Q000187:drug effects; D006801:Humans; D019934:International Normalized Ratio; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000209:etiology / Q000517:prevention & control; D013916:Thrombelastography; D013927:Thrombosis / Q000517:prevention & control; D014859:Warfarin / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D005337:Fibrin
keywords: Atrial fibrillation; chronic renal disease; fibrinolysis; thrombelastograph; thrombosis