title: Whole blood viscosity: Effect of hemodialysis treatment and implications for access patency and vascular disease.
abstract: BACKGROUND
  Hemodialysis patients have increased mortality from cardiovascular complications. Whole blood viscosity (WBV) and red cell aggregation (RCA) may influence the pathogenesis of vascular complications in this population. The objective of this study was to determine whether the hemodialysis treatment or vascular complications were associated with impaired WBV or RCA.
  
  
  METHODS
  This prospective, cross sectional investigation included 38 patients receiving chronic hemodialysis. Blood samples for WBV, RCA and hematocrit were drawn before and after dialysis. WBV was determined between 10 and 780 s-1 and RCA was measured by calculating aggregate shape parameter. WBV and RCA were subsequently assessed for correlation with a history of vascular disease.
  
  
  RESULTS
  The mean WBV, aggregate shape parameter, and hematocrit post-dialysis were significantly higher than pre-dialysis values (p < 0.05). Using a linear model with WBV as the dependent variable, the covariates of aggregate shape parameter, hematocrit, weight, and history of diabetes were not significant. However, pre/post timing of the sample was a significant covariate. WBV correlated with prior access thrombosis or stenosis, especially if the patient had a history of peripheral vascular disease.
  
  
  CONCLUSIONS
  Higher WBV correlated with an increased incidence of access failure and vascular disease. Repetitive increases in WBV and RCA with each dialysis treatment could contribute to vascular dysfunction in this patient population.
authors.affiliation: Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL 60637, USA.
authors.forename: Promila
authors.initials: P
authors.lastname: Dhar
authors.forename: Michael
authors.initials: M
authors.lastname: Eadon
authors.forename: Patrick
authors.initials: P
authors.lastname: Hallak
authors.forename: Ramon Augustine
authors.initials: RA
authors.lastname: Munoz
authors.forename: Mary
authors.initials: M
authors.lastname: Hammes
mesh_terms: D001809:Blood Viscosity; D003430:Cross-Sectional Studies; D004903:Erythrocyte Aggregation; D006400:Hematocrit; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D016491:Peripheral Vascular Diseases / Q000209:etiology*; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D014654:Vascular Patency