Erythrocyte Aggregation and Blood Viscosity is Similar in Homozygous Sickle Cell Disease Patients with and without Leg Ulcers

Background There is no consensus regarding the role of red blood cell (RBC) aggregation in the pathogenesis of leg ulcers (LUs) in sickle cell disease (SCD). Objectives We sought to evaluate whether the cross-sectional determination of RBC aggregation and hematological indices were associated with the presence of LU in homozygous SCD. Methods Twenty-seven patients with LU and 23 with no history of ulceration were recruited into the study. A laser-assisted rotational red cell analyzer (LoRRca) was used in the determination of the aggregation index (AI), aggregation half-time (t(1/2)), and the RBC aggregate strength (AMP). Hematological indices were determined using a CELL-DYN Ruby analyzer. Whole blood viscosity (WBV) and plasma viscosity (PV) were measured using a Vilastic bioprofiler. The data were presented as means +/- standard deviation or median, interquartile range. Two-sample t-test was used to test for associations between the AIs, WBV, and PV in patients with and without LU. Statistical significance was taken as p < 0.05. All analyses were conducted using Stata/SE v. 12.1 (StataCorp, College Station, TX). Results The AI was comparable in the group with and without ulcers (68.6, 16.7 versus 67.7, 16.9; p = 0.74); t(1/2) (1.7, 1.3 versus 1.8, 1.3; p = 0.71); AMP (18.8, 14.5 versus 19.1, 13.3; p = 0.84), WBV (3.8, 1.2 versus 3.8, 0.7; p = 0.77); and the PV (1.3, 0.08 versus 1.4, 0.1; p = 0.31) and were also not statistically different between the groups of participants. Conclusion RBC aggregation and aggregate strength are not associated with leg ulceration in SCD.