Risk Stratification and Assessment of Renal Function Post Shock Wave Lithotripsy (ESWL): Role of Complementary Radionuclides and Color Doppler (Pilot Study)

Background: Shock wave lithotripsy (ESWL) is the prefered initial treatment for approximately 80-85% of renal stones. However, there is controversy regarding which of available techniques is the most efficacious. Aim of the Study: Assess the effect of ESWL on renal function and the role of risk factors on its effect on renal function. Patients and Methods: One hundred patients with unilateral non-obstructing renal stones had been subjected to the current study. They all have been subjected to: 1- Clinical assessment looking for the risk factors, 2- Laboratory investigation for renal function, serum renin pre and post ESWL, 2- Duplex sonography for resistive index, and 3- Radionuclide for perfusion index (PI), GFR, and ERPF total and split function, with follow-up till 12 months post ESWL. The one hundred patients had been divided according to the PI of the obstructed kidneys into three groups: Group I: Included 48 patients with normal PI and defined as acute obstruction group, Group II: Included 30 patients with reduced PI and defined as chronic obstruction, Group III: Included 22 patients with reduced PI but normal or supernormal function and defined as acute on top of chronic obstruction. Results: Most of the cases that showed normalization of renal function were seen in group I (37/57 i.e. 64.9%) and III (15/57, i.e. 26.3%). Meanwhile, 15/22 of group III i.e. 68.2% showed improvement in renal function. Concerning risk stratification, most of the old aged patients were found in group II (chronic obstruction) (23/29 i.e. 79.3%) and then group III 6/29 i.e. 20.7%, mean while group I showed non in old age. Diabetic patients were found all in group II except one in group I. Systemic diseases were found in 5 of group I, 1 of group II and 3 of group III. Six cases in group II were old age, hypertensive and diabetic, 2 cases were hypertenive and diabetic. On the other hand, 3 cases in group III were old age and hypertensive. Six cases having hypertension and diabetes mellitus were found in group I, 2 cases in group II and 2 cases were found in group III. There is significantly higher prevalence of the risk factors (more than one) in the cases with same or deteriorated function in the three groups. versus 1/37 (2.7%) in improving group I, non in five cases with improved function in group II showed risk factors, and only 5/15 (33.3%). Conclusion: Complementary radionuclide and Duplex can be used to assess impact of ESWL on renal function and risk stratification for selecting cases for ESWL.