Renal disease potentiates the injury caused by SWL

Purpose: The present study tested the hypothesis that renal disease potenti ates the structural/functional changes induced by a clinical dose of shockw aves, Materials and Methods: Experimental pyelonephritis was induced in 6- to 8-w eek-old pigs before treatment with 2000 shocks at 24 kV, These pigs were di vided into two groups according to whether they were infected with a highly virulent (Group 1) or less virulent (Group 2) inoculation off. coli, All a nimals were imaged by MR prior to SWL as a means of documenting the extent of pyelonephritis and immediately after SWL to examine the lesion produced by the shockwaves. The glomerular filtration rate (GFR), renal plasma flow (RPF) and para-aminohippurate (PAH) extraction were determined bilaterally on day 30 (Group 1) or day 80 (Group 2), Results: In group 2, urine flow and sodium excretion were reduced by 50% fr om baseline in the shocked kidneys at both 1 and 4 hours post-SWL, A sustai ned reduction in RPF through 4 hours post-SWL was noted in the shocked kidn eys in Group 1, but RPF was significantly reduced only at the 1-hour determ ination in Group 2, Large, consistent reductions in GFR were evident at 1 a nd 4 hours post-SWL in shocked and unshocked kidneys of Group 2 and in the shocked kidneys of Group 1. No significant changes were noted in PAH extrac tion, Conclusion: Acute pyelonephritis exaggerated the effect of a clinical dose of shockwaves on renal hemodynamics. This effect suggests that renal diseas e may be risk factor for SWL-induced injury.