Extracorporeal shock wave lithotripsy at 60 shock waves/min reduces renal injury in a porcine model

OBJECTIVE To determine if extracorporeal shock wave lithotripsy (ESWL) at 60 shock waves (SWs)/min reduces renal damage and haemodynamic impairment compared to treatment at 120 SWs/min. MATERIALS AND METHODS One kidney in each of 19 juvenile pigs (7–8 weeks old) was treated at 120 or at 60 SWs/min (2000 SWs, 24 kV) with an unmodified HM-3 lithotripter (Dornier Medical Systems, Kennesaw, GA, USA). Renal function was determined before and after ESWL treatment by inulin clearance, extraction and clearance of para-aminohippuric acid. Both kidneys were then removed to measure parenchymal lesion size by sectioning the entire kidney and quantifying the size of the haemorrhagic lesion in each slice. RESULTS ESWL at 60 SWs/min significantly reduced the size of the acute morphological lesion compared to 120 SWs/min (0.42% vs 3.93% of functional renal volume, P = 0.011) and blunted the decrease in glomerular filtration rate and renal plasma flow normally seen after treatment at 120 SWs/min. CONCLUSIONS Treatment at a firing rate of 60 SWs/min produces less morphological injury and causes less alteration in renal haemodynamics than treatment at 120 SWs/min in the pig model of ESWL-induced renal injury.