Importance of Renal Resistive Index as a Prognostic Marker in Unilateral Hydronephrosis Due to Ureteropelvic Junction Obstruction.

BACKGROUND

Hydronephrosis is the most common congenital anomalies of the urinary tract. There are various diagnostic modalities which are currently used for diagnosis and follow-up such as ultrasound, renal scintigraphy, intravenous urography, and magnetic resonance urography. Renal arterial Doppler resistance index can be used as a complimentary tool.

MATERIALS AND

METHODS

A prospective observational study of 30 infants and children with unilateral hydronephrosis were selected using consecutive sampling. Ultrasonography with renal biometry for diagnosis and Technetium 99m-diethylene triamine penta-acetic acid (99mTc-DTPA) Renogram was used for functional assessment. Doppler ultrasonography was done in all on to determine mean resistive index in each subject.

RESULTS

Altogether 30 patients have been studied in this series, out of which 7 are females and 23 males. Fourteen patients had left-sided ureteropelvic junction (UPJ) obstruction and 16 had right-sided UPJ obstruction. Operative procedure (Anderson-Hyne's pyeloplasty) was done in all 30 patients. Preoperatively differential renal function was assessed by renal scintigraphy using 99 mTc-DTPA and Doppler ultrasonography done to measure renal resistive index (RRI). In this study, in preoperative group mean peak systolic velocity (PSV) - 52.663 cm/s, mean end diastolic velocity (EDV) - 10.305 cm/s, mean RRI - 0.797, mean DTPA - 43.630. In the postoperative period after 3 months, mean PSV - 41.223, mean EDV - 14.640, mean DTPA - 47.449, and mean RRI - 0.638.

CONCLUSION

This study has shown that the mean renal arterial resistive index was higher (mean RRI - 0.797) in preoperative period and decreased after intervention (mean RRI - 0.638). These values correlate well with DTPA result. Hence, this is a reliable tool for diagnosis and follow-up after intervention.