Evaluation of Renal Arterial Resistivity Index and Some Biochemical Parameters in Sickle Cell Disease: A Preliminary Study for Early Detection of Renal Impairment

Abstract

Background: The Doppler Resistive Index (RI) measures intrarenal arterial resistance. It is increased  in  a  number  of  kidney diseases and considered a marker of renal function, which could serve as an early radiologic predictor of renovascular changes in sickle cell disease (SCD).

Aims and Objective: This study evaluated selected biochemical markers of renal functionand renal Doppler RI in a cohort of Nigerian adults with SCD and Hb AA controls.

Materials and Methods: Forty-four  Hb  SS  patients  in  steady  state  (M:F  = 1.2:1; median age is 24.5) and 22 Hb AA age and sex-matched controls were recruited consecutively into  the  study.  All  had  serum  biochemical  tests including  serum  cystatin-C,  serum  kidney  injury molecule-1 and serum creatinine while urinary albumin-creatinine  ratio  was  also  evaluated.  The right renal artery Doppler RI was also evaluated in the segmental/interlobar arteries while relevant nonparametric tests were used to compare the biochemical and Doppler parameters between the subjects and the controls.

Results: Serum creatinine ranged from subnormal to mildly elevated levels in patients with Hb SS (33245µmol/l)  and  the  median  (range)  renal  arterial Doppler RI was 0.70 (0.49-0.81). The other parameters  evaluated  were significantly  higher  in patients relative to the controls. Of the biochemical parameters, urinary albumin- creatinine ratio showed a weak but statistically significant positive correlation with renal arterial Doppler RI (r=0.329; p= 0.029),  while  serum  cystatin-C  and  kidney  injury molecule-1 had no correlation (r = 0.152 and 0.188 respectively; p = 0.324 and 0.22).

Conclusion: Renal arterial Doppler Resistivity Index has a linear relationship with urinary albumin-creatinine ratio and could therefore be a potential marker of early renal impairment in patients with SCD.