Clinical Significance of Renal Resistive Index Measured by Doppler Sonograpy in Patients with Liver Cirrhosis

Cirrhotic patients may exhibit circulatory derangement and renal dysfunction during the clinical course. Renal dysfunction on cirrhosis can occur without specific causative factors. This functional renal failure in cirrhosis is considered as a consequence of renal vasoconstriction. These alteratons of renal hemodynamics are already present in the early phase of the disease, even in the condition that the conventional kidney function tests are normal. A new method for noninvasive evaluation of arterial tone is duplex Doppler sonography. Among the various sonographic indices proposed, the renal resistive index(RI) is the most widely used for the estimation of intrarenal arteriolar vascular resistence.

This study was performed to evaluate the role of Doppler sonography in early detection of renal dysfunction and to assess the clinical significance of RI. In 25 cirrhotic patients without overt kidney failure and ten control subjects, the RI of the acurate artery in both kidneys was measured by Doppler sonography. The mean RI of cirrhotic group was significangly higher than that of control subjects(0,68±0.08 vs -0.62±0.05,p<0). Accordiing to Child class, the RI showed increasing tendency from A to C, through witout statistical significance. In this study, the RI was significantly inversely correlated with 24hr urinary sodium amount(r=-0.39, p<0,05)and correlated with serum creatinine(r=6.60,p<0.01). This study indicates that the measurement of RI is a sensitive method to assess intarenal hemodynamics and to detect early changes of the renal dysfunction in cirrhotic patients.