Abstract

Threshold for Prevention of SWL-Induced Renal Injury and Hemorrhage by Pre-Treatment of Kidneys with Low-Energy Shock Waves

L.R.Willis (Department of Pharmacology/Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA); A.P.Evan, B.A.Connors, Y.Shao, P.M.Blomgren (Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA); J.E.Lingeman (Methodist Hospital Institute for Kidney Stone Disease, Indianapolis, IN, USA)

e-mail: willisl@iupui.edu

Pre-treatment of one renal pole with 2000 low-energy shock waves (SWs; 12 kV) protects the opposite pole from hemorrhagic injury normally caused by 2000 SWs at 24 kV. These studies sought the minimum number of low-energy SWs needed for this protection. Anesthetized, 6-week old pigs received either 100 or 500 SWs at 12 kV to one renal pole, then 2000 SWs at 24 kV to the opposite pole (Dornier HM3, 2 Hz). Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured 1 hr before and 1 and 4 hrs after SWL. The kidneys were then removed, perfusion-fixed, sectioned sequentially and digitized for quantification of lesion size. Reductions of RPF and GFR occurred after SWL in both groups. Two thousand SWs at 24 kV typically cause subcapsular hematoma, ablation of one or more papillae, and hemorrhagic lesions in cortex and papilla. We saw only small lesions in 1 or 2 papillae, but no subcapsular hematomas or cortical lesions. Administration of as few as 100 SWs at 12 kV protected kidneys from damaging effects of 2000 SWs at 24 kV. The protective threshold appears to be below 100 SWs. The appearance of small papillary lesions as the only injury supports the hypothesis that papillary tissue is most susceptible to SW-induced damage.

Section : 5