#822 Effect of renal Doppler ultrasound on the detection of nutcracker syndrome in children presenting orthostatic proteinuria

Abstract Background and Aims To assess the Doppler sonographic findings of the left renal vein (LRV) in children with orthostatic proteinuria compared to normal urine children. Method Renal Doppler ultrasound examinations were routinely performed on 50 consecutive children with orthostatic proteinuria and 53 normal urine children who have visited to the pediatric nephrology clinic at Severance hospital. The peak velocity (PV) was measured at the hilar portion of the left renal vein (LRV) and at the LRV between the aorta and the superior mesenteric artery. Results Age and sex did not differ between the two groups. The peak velocity ratios between aortomesenteric and hilar portions were 7.79+/−2.65 in children with orthostatic proteinuria and 6.32+/−3.01 in healthy normal children (p=0.01). The protein/creatinine ratio in the first morning urine did not differ between the two groups (0.09+/−0.03 in children with orthostatic proteinuria and 0.08+/−0.02 in healthy normal children (p = 0.144). However, the protein/creatinine ratio in the afternoon urine in children with orthostatic proteinuria (0.49+/−0.46) was significantly higher than that in healthy normal children (0.10+/−0.04) (p < 0.001). The peak velocity ratios between aortomesenteric and hilar portions positively correlated with the protein/creatinine ratio between the afternoon urine and the first morning urine (R = 0.21, P = 0.034). Conclusion Nutcracker syndrome may be an important cause of orthostatic proteinuria in children. Renal Doppler ultrasound of the LRV may be a useful screening tool in patients with suspected orthostatic proteinuria to evaluate whether the cause is nutcracker syndrome.