Is red blood cell distribution width being a marker of red blood cell dysfunction in the microcirculation in patients with heart failure

Background

An increase in red blood cell distribution width (RDW) is associated with a negative prognosis for most cardiovascular diseases (CVD). The role of RDW and red blood cell (R) dysfunction as a factor potentially worsening the course of chronic heart failure (CHF) through impaired microcirculation is poorly studied.

Objective

To study the relationship between RDW indicators and RBC deformability and aggregation parameters in patients with chronic heart failure (CHF).

Materials and methods

The study included 48 patients with CHF with low and moderately reduced left ventricular ejection fraction (LVEF) and 11 volunteers without CVD. All participants underwent routine clinical blood tests, and the deformability and aggregation parameters of RBC were measured using the laser diffractometry and aggregometry techniques accordingly.

Results

Patients with CHF demonstrated significantly higher values of RDW-CV (14.4 (13.2; 16.2) vs the control values 12.8 (12.2; 13.4) %, p=0.005) and RDW-SD (48.2 (45.2; 53.7) vs 42.7 (41.6; 44.0) fl, p=0.001). In the CHF group with RDW-CV ≥16%, the increased indices of spontaneous RBC aggregation were revealed: M-index (10.8 ± 2.0 vs 8.9 ± 2.0, p=0.007), A1 (0.040 ± 0.005 vs 0.034 ± 0.007, p<0.001) and parameter A1+A2 (0.062 ± 0.009 vs 0.052 ± 0.012, p=0.004). We did not find any statistically significant differences in the parameters characterizing the deformability of RBC between groups of CHF patients with RDW-CV ≥16% and RDW-CV <16%: DI(3 Pa) (0.32 ± 0.03 vs 0.32 ± 0.02, p=0,608), DI(20 Pa) (0.50 ± 0.03 vs 0.50 ± 0.02, p=0,905), shear yield (0.17 ± 0.07 Pa vs 0.18 ± 0.12 Pa, p=0,968), viscosity of internal content of RBC (4.15 ± 0.35 vs 4.05 ± 0.47, p=0,199).

Regression analysis showed that RDW-CV is significantly associated with the parameters characterizing spontaneous erythrocyte aggregation and its degree (M-index, β=0.49 95CI[0.08;0.90], p=0.021; y0, β=34.31 95CI[8.30;60.32], p=0.012) and the parameter characterizing the degree of expression of the formation of linear (A1 β=154.43 95CI[28.06;280.79], p=0.019) erythrocyte aggregates in whole blood.

Also, regression analysis showed that RDW-CV is not associated with the deformability parameters of RBC: DI(3 Pa) (β=0.292 95CI[-1.39;1.98], p=0.731) and DI(20 Pa) (β=-0.58 95CI[-2.08;0.93], p=0.443) deformability index of RBC at shear stress 3 and 20 Pa, shear yield (β=0.242 95CI[-0.74;1.23], p=0.622) and viscosity of internal content of RBC (β=0.036 95CI[-1.23;1.31], p=0.955).

Conclusion

Our analysis showed that higher RDW values are not associated with impaired RBC deformability in patients with CHF, but are likely associated with increased red blood cell aggregation in the microcirculatory bed; however, given the limited sample size, especially in subgroup analyses, small differences in deformability cannot be excluded.