Renal vascular Doppler ultrasonographic indices and carotid artery intima-media thickness in diabetic nephropathy

Introduction: Diabetes is one of the common causes of renal insufficiency and is responsible for about one third of cases requiring renal transplantation. Conventional sonography provides limited information regarding the severity and prognosis of disease. The present study was carried out to evaluate the renal vascular Doppler indices role in determining renal dysfunction and carotid artery atherosclerosis. Methods: Fifty five patients with diabetic nephropathy (albuminuria more than 300mg/24 hours) were enrolled into this cross-sectional study. Renal interlobar arterioles were studied using resistive (RI) and pulsatility (PI) indices of Doppler ultrasonography, in addition to conventional kidney length and renal parenchyma thickness. Intima-media thickness of common carotid artery (CCIMT) was also assessed just before the bifurcation. Serum creatinine (sCr), urine albumin and lipid profile were measured using standard methods. Estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease formula. Results: The renal interlobar arterioles' RI was positively and linearly correlated with the sCr and albuminuria levels (P<0.039 r= +0.320 and P=0.047, r= +0.287). There were negative linear correlations between eGFR and the renal interlobar arterioles' RI (P<0.001, r=-0.539) and PI (P<0.045, r= -0.328). The mean CCIMT was more than 0.7 mm in 90% of the studied patients. No correlation was found between CCIMT and renal ultrasonographic and Doppler findings. Conclusion: Although Doppler ultrasonographic indices of renal interlobar arteriols show the severity of renal dysfunction in patients with diabetic nephropathy, these indices do not have any advantage over the simple and cost effective biochemical parameters.