Changes of renal blood flow in nephroptosis: assessment by color Doppler imaging, isotope renography and correlation with clinical outcome after laparoscopic nephropexy.

OBJECTIVE: Previously, we have detected changes in renal blood flow secondary to nephroptosis by assessing the renal resistive index (RI) using color Doppler imaging (CDI). The aim of the current study was to compare two diagnostic methods, CDI and isotope renography (IRG), for detection of renal blood flow impairment in patients with nephroptosis.
METHODS: 26 patients with nephroptosis and flank pain underwent CDI and isotope renography (IRG) before and after laparoscopic nephropexy. The RI was assessed in segmental arteries with the patient in both the supine and erect position. Pre- and postoperative patient symptoms, results of Doppler measurements and IRG findings were assessed.
RESULTS: Preoperatively, 23 of 26 symptomatic patients showed a mean reduction in RI of more than 0.10 on the affected side, while only 7 of 26 patients had abnormal findings on preoperative IRGs. Postoperatively, none of the patients with preoperative changes in Doppler parameters showed any posture-related changes in RI. On postoperative IRG, obtained in 4 of 7 patients, normalization of renal perfusion was documented. Twenty out of 26 patients were asymptomatic postoperatively; in the remaining 6 patients symptoms were markedly improved.
CONCLUSION: Impairment of renal blood flow due to nephroptosis was detected with both CDI and IRG. RI measurement by CDI appears to be significantly more sensitive in detecting renal blood flow impairment. RI should be assessed in patients with nephroptosis and may impact on the decision for laparoscopic nephropexy.