title: The Forgotten Variable of Shear Stress in Mitral Annular Calcification: Whole Blood Viscosity.
abstract: OBJECTIVE
  The aim of this research was to assess the relationship between mitral annular calcification (MAC) and whole blood viscosity (WBV).
  
  
  METHODS
  A total of 184 patients with MAC and 133 patients without MAC were enrolled in the study. The WBV was calculated with a confirmed formulation using the hematocrit and total plasma protein at a low shear rate (LSR) and high shear rate (HSR). Early diastolic mitral annular velocity (Ea) and late diastolic mitral annular velocity (Aa) were measured using pulse Doppler tissue echocardiography. Pearson's correlation analysis was performed to assess the relationship between WBV and mitral annular motion velocities. The effects of different variables on the occurrence of MAC were assessed in univariate and multivariate logistic regression analysis.
  
  
  RESULTS
  In patients with MAC, WBV values were significantly higher at HSR (18.04 ± 0.84 vs. 17.25 ± 0.96 208 s(-1), p < 0.001) and at LSR (78.0 ± 14.2 vs. 61.9 ± 17.1 0.5 s(-1), p < 0.001). The WBV at HSR and LSR were significantly correlated with Ea (r = -0.477, p < 0.001; r = -0.385, p < 0.001, respectively) and Aa (r = -0.544, p < 0.001; r = -0.323, p < 0.001, respectively). Multivariate analysis showed that WBV of both shear rates was an independent predictor of MAC. Using the ROC curve, a cut-off value of 70.1 for WBV at LSR had a sensitivity of 83.7% and a specificity of 73.7% (AUC 0.785, p < 0.001) and a WBV cut-off value of 17.5 at HSR had a sensitivity of 79.6% and a specificity of 71.4% (AUC 0.761, p < 0.001) for the prediction of MAC.
  
  
  CONCLUSIONS
  Patients with MAC had significantly higher WBV, which independently predicted the presence of MAC. WBV had an inverse correlation with mitral annular motion velocities, indicating that a higher WBV may lead to greater limitation in annular motion and, thus, more calcification.
authors.affiliation: Cardiology Clinic, Yuksek Ihtisas Training and Research Hospital, Ankara, Turkey.
authors.forename: Elif Hande
authors.initials: EH
authors.lastname: Ozcan Cetin
authors.forename: Mehmet Serkan
authors.initials: MS
authors.lastname: Cetin
authors.forename: Ugur
authors.initials: U
authors.lastname: Canpolat
authors.forename: Erol
authors.initials: E
authors.lastname: Kalender
authors.forename: Serkan
authors.initials: S
authors.lastname: Topaloglu
authors.forename: Dursun
authors.initials: D
authors.lastname: Aras
authors.forename: Sinan
authors.initials: S
authors.lastname: Aydogdu
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001809:Blood Viscosity / Q000502:physiology*; D002114:Calcinosis / Q000097:blood* / Q000000981:diagnostic imaging; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D006349:Heart Valve Diseases / Q000097:blood* / Q000000981:diagnostic imaging; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D012372:ROC Curve