title: Hematologic correlates of left atrial spontaneous echo contrast and thromboembolism in nonvalvular atrial fibrillation.
abstract: OBJECTIVE
  This study examined the relation between left atrial spontaneous echo contrast, hematologic variables and thrombo-embolism in patients with nonvalvular atrial fibrillation.
  
  
  BACKGROUND
  Left atrial spontaneous echo contrast is associated with left atrial stasis and thromboembolism in patients with nonvalvular atrial fibrillation. However, its hematologic determinants in patients with nonvalvular atrial fibrillation are unknown.
  
  
  METHODS
  Clinical, hematologic and echocardiographic variables were prospectively measured in 135 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography.
  
  
  RESULTS
  Patients with left atrial spontaneous echo contrast (n = 74, 55%) had an increased fibrinogen concentration (p = 0.029), platelet count (p = 0.045), hematocrit (p = NS) and left atrial dimension (p = 0.005). Multivariate analysis showed that left atrial spontaneous echo contrast was independently related to hematocrit (odds ratio = 2.24, p = 0.002), fibrinogen concentration (odds ratio = 2.08, p = 0.008) and left atrial dimension (odds ratio = 1.90, p = 0.004) but not platelet count. It was also associated with left atrial thrombus (n = 15, p = 0.001) and with recent embolism (n = 40, p < 0.001). In 40 clinically stable outpatients without previous embolism, left atrial spontaneous echo contrast was significantly related to hematocrit (p = 0.005), fibrinogen concentration (p = 0.035) and left atrial dimension (p = 0.029) but not to coagulation factor VII, D-dimer, erythrocyte sedimentation rate, platelet count, plasma beta-thromboglobulin, plasma glycocalicin or glycocalicin index.
  
  
  CONCLUSIONS
  Left atrial spontaneous echo contrast in patients with nonvalvular atrial fibrillation is independently related to hematocrit, fibrinogen concentration and left atrial dimension, indicating a relatively hypercoagulable state in addition to stasis. These findings support the hypothesis that left atrial spontaneous echo contrast is due to erythrocyte aggregation. Hematologic factors may contribute to its association with thromboembolism.
authors.affiliation: Department of Cardiovascular Medicine, Prince Henry Hospital, Sydney, Australia.
authors.forename: I W
authors.initials: IW
authors.lastname: Black
authors.forename: C N
authors.initials: CN
authors.lastname: Chesterman
authors.forename: A P
authors.initials: AP
authors.lastname: Hopkins
authors.forename: L C
authors.initials: LC
authors.lastname: Lee
authors.forename: B H
authors.initials: BH
authors.lastname: Chong
authors.forename: W F
authors.initials: WF
authors.lastname: Walsh
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging*; D016279:Atrial Function, Left / Q000502:physiology; D004452:Echocardiography / Q000379:methods; D004903:Erythrocyte Aggregation / Q000502:physiology; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006400:Hematocrit; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012307:Risk Factors; D013923:Thromboembolism / Q000097:blood / Q000453:epidemiology / Q000209:etiology*
chemical_list: D005340:Fibrinogen