Renal Doppler Indices in patients with Sickle Cell Disease; is it helpful for early detection of Sickle Cell Nephropathy?

Background: The major complications in Sickle Cell Disease (SCD) are microcirculation lesions and impairment of renal function. The aim of the present study is to detect changes of renovascular resistance through renal Doppler indices in young sickle cell disease patients with normal routine urine and renal laboratory tests as a tool for early detection of sickle cell nephropathy. Patients and methods: Fifty four patients with SCD, were divided into two groups: (Group 1) (25 patients with frank sickle cell nephropathy) with mean age (41.3±5.9 years), (Group2) (29 patients with SCD and normal renal function tests) with mean age of (27.9± 7.9 years ) and (Group3) 29 age and sex matched healthy subjects (mean age 28.5 ±9.9 years) were included as a control group. Group 2 were further sub divided into 19 patients with VasoOcclusive Crises (VOC) and 10 patients during the steady state. The patients and control groups recruited from the Medical Department of King Fahd Hospital- Hofuf Eastern Province-Saudi Arabia. Doppler indices in the form of Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Resistive index (RI){PSV-EDV/PSVf and Pulsatility Index (PI) were measured in the main and segmental renal arteries for all groups. Results: A total of fifty four patients with SCD were divided into Group 1 (25 patients) with sickle cell nephropathy , Group 2 ( 29 patients ) with normal renal functions They were compared to (Group3) a control group of 29 healthy subjects and showed: Significant higher value of R1 in the main renal artery was detected among group 1 and group 2 in comparison to group 3 with mean value of (0.84±0.05, 0.73± 0.06 and 0.54+0.07) respectively with p 0.01. Also there were higher values of Rl in the segmental arteries among the group 1 and group 2 in comparison to group 3 with mean values (0.84±0.04 , 0.74+0.06 and 0.53±0.07) respectively with p 0.01. As regard the PI value, it was also found to be higher in the main as well as in the segmental renal arteries in the group] and group 2 in comparison to group 3 with mean value of (2.23±0.33, 1.35+0.48 and 0.84+0.09 ) with p 0.05 and (2.1 ±0.32, 1.4+0.62 and 0.84+0.09 ) with p =0.01 respectively. On observing the RI and PI among group 2, we found significantly higher values of RI in the main renal arteries in 17 patients out of 29 patients with mean value of (0.74+0.03 vs 0.66± 0.03, p 0.01) and PI was higher in 19 patients out of 29 with mean value of (1.42+0.60 vs 0.99+0.14, p 0.05). Also the same findings were detected in the segmental renal arteries, for RI where the value was higher in 17 patients out of 29 patients with mean values of (0.72+0.02 vs0.65+0.04 , p 0.01), and for PI the value was significantly higher in 19 patients out of 29 patients, with mean value of ( 1.39+0.4 vs 1.1 ±0.11, p 0.01). By comparing the RI and PI among group 2 in patients with VOC (19 patients ) vs (10 patients ) in steady state , we found a significant changes among VOC subcategory regarding RI in both main and segmental renal arteries respectively with mean values of (0.73+0.03 vs 0.67± 0.02 , p 0.01 0.71+0.03 vs 0.66 +0.02, p 0.01 ) respectively. As regard PI, it was found to be significantly higher in the main as well as in the segmental renal arteries in the sub group of patients with VOC with mean value of (1.50+0.3 vs 1.1 ±0.15, p 0.01 and 1.38+0.33 vs 0.99±0.4, p 0.01) respectively. When comparing renal indices among group 2 in patients with high normal creatinine level (80-97umol /L) to patients with creatinine below the lower limit of normal range (below 55 umol/L), we found significantly higher values of RI and PI in both main and segmental renal arteries with p 0.01 inthe sub group of high normal creatinine values. In conclusion: Renal Doppler indices like resistivity indexand pulsatility index can be used as an early radiologic predictors predictors of renovascular changes in Sickle Cell Disease especially with high normal creatinine level.