Determinants of Intrarenal Vascular Resistance in Congolese Sickle Cell Patients in Kinshasa: A Hospital-Based Study

Objective: The aim of our study was to detect early changes in renovascular resistance through renal Doppler indexes in sickle cell disease (SCD) patients. Methods: By a cross-sectional study, two groups were consecutively examined with duplex ultrasound from 1 January to 30 September 2011. One group consisted of patients with SCD attending the sickle cell outpatient clinic, 61 homozygous (SS pattern, mean age 16 years) and 21 heterozygous (AS pattern, mean age 15 years). The other group was a control group consisting of randomly selected patients who were routinely attending the sonography division for non renal abdominal sonography. All control patients were age matched with patient group (within 1 year) to remove the confounding effect of age. The resistive (RIs) and pulsatility (PIs) indices of the main as well as intrarenal arteries were compared among groups. Results: Homozygous SCD patients had significantly higher RIs and PIs in the intrarenal arteries (P = 0.001) compared to controls while there was no significant differences in RIs and PIs between heterozygous SCD patients and controls. Among SCD patients RIs in the intrarenal arteries positively correlated with eGFR (r = 0.36; p = 0.001), pulse pressure (r = 0.25; p = 0.001), white blood cell (r = 0.36; p = 0.001) and negatively correlated with hemoglobin (r = 0.83; p = 0.001). In multivariate linear regression analysis, the relation persisted only for hemoglobin which explained 61% of the variation of RIs. Conclusion: The present study documents that there are early intrarenal hemodynamic alterations among SCD patients. This implies that the duplex evaluation of the intrarenal arteries, could be a useful non invasive procedure for monitoring SCD patients and could help detect persons at risk of developing SCD nephropathy.