title: Left atrial blood stasis and Von Willebrand factor-ADAMTS13 homeostasis in atrial fibrillation.
abstract: OBJECTIVE
  Left atrial blood stasis is associated with increased risk for left atrial appendage thrombus (LAAT) and stroke in atrial fibrillation (AF). Von Willebrand factor (VWF) is associated with thromboembolism in AF. VWF thrombogenic activity is proportional to multimer size, which is regulated by VWF-cleaving protease (ADAMTS13).
  
  
  RESULTS
  To assess the association between left atrial blood stasis and VWF-ADAMTS13 system, plasma VWF antigen (VWF:Ag), VWF activity (VWF:Act), and ADAMTS13 activity were measured in 414 consecutive patients with nonvalvular AF (age 63±13 years; 25% women) and in 100 patients (age 64±14 years; 39% women) with normal sinus rhythm. Spontaneous echocardiographic contrast (SEC), left atrial appendage emptying velocity, and LAAT were assessed by transesophageal echocardiography. Presence and intensity of SEC varied directly with VWF:Ag and VWF:Act but not with ADAMTS13 activity. AF patients with LAAT had higher VWF:Ag (200±61 versus 155±52, P=0.0006) and VWF:Act (179±57 versus 141±51 P=0.0026) compared with those without LAAT. VWF:Ag and VWF:Act were independent predictors of LAAT after adjustment for CHADS2 score (P=0.0179 and P=0.0497, respectively).
  
  
  CONCLUSIONS
  The association between VWF and SEC may explain the thrombotic propensity in AF. Elevated VWF:Ag may help identify AF patients at risk for LAAT.
authors.affiliation: Department of Internal Medicine, Mayo Clinic and Foundation for Education and Research, Rochester, MN 55905, USA.
authors.forename: Naser
authors.initials: N
authors.lastname: Ammash
authors.forename: Ewa A
authors.initials: EA
authors.lastname: Konik
authors.forename: Robert D
authors.initials: RD
authors.lastname: McBane
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.forename: Julie I
authors.initials: JI
authors.lastname: Tange
authors.forename: Diane E
authors.initials: DE
authors.lastname: Grill
authors.forename: Regina M
authors.initials: RM
authors.lastname: Herges
authors.forename: Thomas G
authors.initials: TG
authors.lastname: McLeod
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: Waldemar E
authors.initials: WE
authors.lastname: Wysokinski
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000071120:ADAMTS13 Protein; D000368:Aged; D020517:Atrial Appendage / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000097:blood* / Q000150:complications / Q000503:physiopathology*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D017548:Echocardiography, Transesophageal; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology; D012307:Risk Factors; D013923:Thromboembolism / Q000000981:diagnostic imaging / Q000453:epidemiology; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human