title: Mean platelet volume is associated with the presence of left atrial stasis in patients with non-valvular atrial fibrillation.
abstract: BACKGROUND
  Mean platelet volume has been associated with stroke in patients with atrial fibrillation. However, its role as a predictor of left atrial stasis, assessed by transesophageal echocardiography, in patients with non-valvular atrial fibrillation has not yet been clarified.
  
  
  METHODS
  Single center cross-sectional study comprising 427 patients admitted to the emergency department due to symptomatic atrial fibrillation and undergoing transesophageal echocardiogram evaluation for exclusion of left atrial appendage thrombus before cardioversion. All patients had a complete blood count performed in the 12 hours prior to transesophageal echocardiogram. Markers of left atrial stasis were sought: left atrial appendage thrombus, dense spontaneous echocardiographic contrast and low flow velocities in the left atrial appendage. The presence of at least one of the former markers of left atrial stasis was designated left atrial abnormality. Binary logistic multivariate analysis was used for obtaining models for the prediction of transesophageal echocardiogram endpoints.
  
  
  RESULTS
  Left atrial appendage thrombus was found in 12.2%, dense spontaneous echocardiographic contrast in 29.7%, low flow velocities in 15.3% and left atrial abnormality in 34.2%. Mean platelet volume (exp β = 3.41 p = 0.048) alongside with previous stroke or transient ischemic attack (exp β = 5.35 p = 0.005) and troponin I (exp β = 5.07 p = 0.041) were independent predictors of left atrial appendage thrombus. Mean platelet volume was also incorporated in the predictive models of dense spontaneous echocardiographic contrast, low flow velocities and left atrial abnormality, adding predictive value to clinical, echocardiographic and laboratory variables.
  
  
  CONCLUSIONS
  These findings suggest that mean platelet volume may be associated with the presence of markers of left atrial stasis, reinforcing a likely cardioembolic mechanism for its association with stroke in patients with non-valvular atrial fibrillation.
authors.forename: Rui
authors.initials: R
authors.lastname: Providência
authors.forename: Ana
authors.initials: A
authors.lastname: Faustino
authors.forename: Luís
authors.initials: L
authors.lastname: Paiva
authors.forename: Andreia
authors.initials: A
authors.lastname: Fernandes
authors.forename: Sérgio
authors.initials: S
authors.lastname: Barra
authors.forename: Joana
authors.initials: J
authors.lastname: Pimenta
authors.forename: Joana
authors.initials: J
authors.lastname: Trigo
authors.forename: Ana
authors.initials: A
authors.lastname: Botelho
authors.forename: António M
authors.initials: AM
authors.lastname: Leitão-Marques
mesh_terms: D000368:Aged; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D004452:Echocardiography; D017548:Echocardiography, Transesophageal; D005260:Female; D006331:Heart Diseases / Q000209:etiology*; D006801:Humans; D008297:Male; D063847:Mean Platelet Volume; D008875:Middle Aged; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology*