Does the administration of systemic radiographic contrast media influence the acute changes in renal physiology following exposure to extracorporeal shock waves in dogs?

Five anesthetized dogs were studied for 4 to 5 hours after administration of extracorporeal shock waves to one kidney, the contralateral organ serving as control. Repetitive major doses of the nonionic monomeric radiographic contrast medium (CM) iohexol were injected intravascularly before and after application of the extracorporeal shock waves for further provocation of kidney function. Urinary excretion of electrolytes, N-acetyl-beta-glucosaminidase (NAG) and kallikrein, clearances of creatinine, inulin and para-amino-hippuric acid (PAH), serum aldosterone level and plasma renin activity (PRA) were determined. On the exposed side there was a significant fall in urinary osmolality. Effective renal plasma flow (ERPF) was reduced and glomerular filtration rate (GFR) was unchanged; thus filtration fraction (FF) was increased. Extraction of PAH was reduced, and true renal plasma flow was unchanged. Urinary osmolality on the control side was unchanged. There was a fall in ERPF and increased GFR; therefore, FF increased. The mean rise of PRA in the exposed kidney was significant after shock waves. Urine volume and urinary excretion of electrolytes and kallikrein were stable bilaterally. Relating the results to those obtained in identical canine experiments without CM, simultaneous administration of CM does not seem to significantly influence the changes in kidney function parameters caused by extracorporeal shock waves in the dog.