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Abstract: TH-PO322

Evaluating Microcirculation Changes in Patients with ESKD during Hemodialysis Using Conjunctival Capillaroscopy

Session Information

Category: Dialysis

  • 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Barnes IV, Sylvester, Loyola University Medical Center, Chicago, Illinois, United States
  • Gaynes, Bruce Ira, Loyola University Medical Center, Chicago, Illinois, United States
  • Murrar, Abedelkarim M., University of Illinois Chicago, Chicago, Illinois, United States
Background

During hemodialysis, there appears to be an internal viscosity change in RBCs, leading to a decrease in their deformability. This change results in a rouleau formation with concurrent changes in microcirculation viscosity.

Methods

Microcirculation impairment is an independent predictor of organ dysfunction and death. Sublingual capillaroscopy has been utilized to visualize capillary flow; however, microcirculation flow in the eye is more representative of the cerebral circulation. We have adapted a commercial sublingual capillaroscopy for use in the conjunctival tissue bed to obtain vessel diameter and blood flow velocity. From Pries et al. discharge hematocrit (Hd) v_b / v = H_D + (1 - H_D) * (1 + 1.7e^(-0.415D) - 0.6e^(-0.011D)) was obtained, then in-vivo viscosity using η_vivo = [1 + (η - 1) * ((1 - H_D)^C - 1) / ((1 - 0.45)^C - 1) * (D / (D - 1.1))^2] * (D / (D - 1.1))^2 where
η = 6e^(-0.085D) + 3.2 - 2.44e^(-0.06D^0.445) was calculated. Previously non-physiologic viscosity was reported.

Results

Our previosuly reported findings in ESRD patients appear to demonstrate profound abnormalities in RBC aggregation and RBC density in the microvasculature post-HD ( Figure 1). We postulated that this would cause a significant change in in-vivo viscosity. However, there was no statistical difference between calculated hematocrit levels or viscosity levels, although with a p-value of 0.06, the decrease in viscosity is close.

Conclusion

Our sample size limits the power of the study. These results show promise in that measured velocity values using capillaroscopy, with calculated in vivo vessel hematocrit and in-vivo viscosity, are within physiological range and provide a valuable way to measure real-time in-vivo blood flow characteristics pre and post HD. With more patient recruitment the power of sour study should increase.