a 73-year - old woman developed acute - onset anuria and renal failure the day after elective extracorporeal shock wave lithotripsy ( eswl ) for a pancreatic stone . her past medical history included chronic alcohol intake , complicated by pancreatitis and polyneuropathy , hypercholesterolaemia , hypertension , peripheral arterial disease , carotid endarterectomy and psoriasis . she had stopped alcohol intake 12 years earlier but was an active smoker ( total of 50 pack - years ) . three months before the current admission , she presented with an acute - on - chronic pancreatitis secondary to a 15-mm stone in the pancreatic duct ; at that time , ct scan incidentally showed a severe atrophy of the right kidney , whereas the left kidney long axis was 11.4 cm ( figure  1a )  . she was admitted to the gastroenterology ward for elective eswl ) followed by endoscopic retrograde sphincterotomy . on admission , she was taking olmesartan 40 mg od , amlodipine 10 mg od , pantoprazole 40 mg od and rosuvastatin 10 mg od ; acetylsalicylic acid had been stopped 1 week before the procedure . serum creatinine level at admission was 1.02 mg / dl [ estimated glomerular filtration rate ( egfr ) 53 ml / min/1.73 m by mdrd ] ; other lab tests are shown in table  1 . the eswl consisted of the administration of 3000 shock waves with a 120/min frequency and with a total energy of 125 j , followed by sphincterotomy , complete extraction of the stone with a balloon catheter and insertion of a pancreatic prosthesis the next day , the pain worsened and anuria was observed . on clinical examination , the temperature was 36.1c , heat rate 88 bpm and blood pressure 180/90 mmhg ; palpation of the epigastric area was tender , with no sign of peritoneal irritation . lab tests showed an acute renal failure ( serum creatinine level 7.32 mg / dl ) ; other results showed a c - reactive protein level at 28.8 mg / dl , white blood cell count of 17750/l , neutrophilic ( 88% ) , increased levels of lactate dehydrogenase ( 742 iu / l ; n < 248 ) , aspartate aminotransferase ( 55 iu / l ; n < 50 ) and alanine aminotranferase ( 80 iu / l ; n < 50 ) ; the levels of alkaline phosphatase , gt and pancreatic lipase were normal . ct scan without iodine contrast media ruled out acute pancreatitis , bowel perforation and ureterohydronephrosis but showed severe and diffuse aortic calcifications involving the ostium of the left renal artery ( figure  1b and c ) . haemodialysis had to be initiated because of fluid overload in the face of anuria . 2day 10day 20month 1month 12eswlptaserum creatinine ( mg / dl)0.61.31.027.325.674.833.383serum urea ( mg / dl)15503712710315813096alt ( iu / l)<50195547162417ast ( iu / l)<507803810118ldh ( iu / l)<248159742320256238188total bilirubin ( mg / dl)0.31.20.30.40.30.50.50.1lipase ( iu / l)<6724432614nd18eswl , extracorporeal shock wave lithotripsy ; pta , percutaneous transluminal angioplasty ; alt , alanine aminotransferase ; ast , aspartate aminotransferase ; ldh , lactate dehydrogenase . 
 fig .  1.ct-scan findings . ( a ) severe atrophy of the right kidney ( arrow ) incidentally found on the ct scan ( coronal sections ; with iodine contrast media ) performed 3 months before current admission . ( b and c ) extensive calcifications of the aorta and the ostium of the left renal artery ( arrowhead ) on the ct scan performed after eswl ( transversal sections ) . the pancreatic prosthesis ( asterisk ) is located in front of the ostium of the left renal artery . eswl , extracorporeal shock wave lithotripsy ; pta , percutaneous transluminal angioplasty ; alt , alanine aminotransferase ; ast , aspartate aminotransferase ; ldh , lactate dehydrogenase . ( a ) severe atrophy of the right kidney ( arrow ) incidentally found on the ct scan ( coronal sections ; with iodine contrast media ) performed 3 months before current admission . ( b and c ) extensive calcifications of the aorta and the ostium of the left renal artery ( arrowhead ) on the ct scan performed after eswl ( transversal sections ) . the pancreatic prosthesis ( asterisk ) is located in front of the ostium of the left renal artery . anuric acute renal failure in the absence of urinary tract obstruction , in a patient with extended vascular calcifications and a solitary functioning kidney , was highly suggestive of renovascular acute renal failure . potential renal viability was suggested by retrospective analysis of the ct scan performed 1 month earlier , with a normal perfusion of the left kidney thanks to collateral vascularization , despite chronic , calcified , ostial stenosis of the left renal artery . left renal artery revascularization was therefore attempted , but femoral catheterization was unsuccessful because of complete iliac artery occlusion . angio - magnetic resonance imaging confirmed this occlusion and demonstrated a 10-mm - ostial subocclusion of the left renal artery with severe renal hypoperfusion ( figure  2a ) ; upper limb arteries were suitable for catheterization . a second attempt through brachial catheterization ( delayed because of pulmonary oedema requiring daily haemodialysis ) allowed successful blood flow restoration after percutaneous angioplasty and stenting of the left renal artery ( figure  2b ) . the day after angioplasty , the patient resumed diuresis after prolonged total anuria , and haemodialysis was withdrawn a few days later . serum creatinine level fell to around 3 mg / dl ( egfr of 15 ml / min/1.73 m ) and stabilized ( figure  3 ) . ( a ) angio - mri showing the absence of vascularization of the left kidney secondary to an ostial occlusion of the left renal artery ( arrowhead ) . haemodialysis was performed immediately after the procedure and on the day after to limit the risk of nephrogenic systemic fibrosis . ( b ) arteriography after percutaneous angioplasty of the left renal artery with successful blood flow restoration . hd , haemodialysis ; pta , percutaneous transluminal angioplasty ; lra , left renal artery ; uo , urinary output . ( a ) angio - mri showing the absence of vascularization of the left kidney secondary to an ostial occlusion of the left renal artery ( arrowhead ) . collateral vascularization suggests chronic blood flow limitation due to atherosclerotic disease . the distal aorta is completely occluded . haemodialysis was performed immediately after the procedure and on the day after to limit the risk of nephrogenic systemic fibrosis . ( b ) arteriography after percutaneous angioplasty of the left renal artery with successful blood flow restoration . hd , haemodialysis ; pta , percutaneous transluminal angioplasty ; lra , left renal artery ; uo , urinary output . we report an unusual case of partly reversible renovascular acute renal failure triggered by eswl performed for chronic pancreatitis . eswl has been recommended to facilitate fragmentation and stone removal , in combination with sphincterotomy of the pancreatic duct and insertion of a stent . this technique was shown to be safe and particularly successful in patients with a single stone , as in our patient . the technique follows physical laws of acoustics and is based on the principle that an abrupt change in acoustical impedance  normally at its focus point , the stone  liberates short - term high - energy mechanical stresses and tear - and - shear forces which eventually lead to disintegration of the stone . eswl for pancreatic stones is usually safe , with a low ( 5% ) overall complication rate . eswl for renal stones has been occasionally associated with vascular damage , both in experimental models and in patients [ 49 ] . localized dissection of the aorta or abdominal aortic rupture has been reported , especially in patients with calcified vessels [ 10 , 11 ] . it has been suggested that the calcified wall might act as an acoustic interface leading to plaque fragmentation and rupture . in our patient with a solitary functioning kidney , eswl for pancreatic stone clearly precipitated acute renal failure , and its renovascular nature was definitively confirmed by successful renal revascularization   and spectacular resolution of anuria . we speculate that the presence of extensive vascular calcifications in the area targeted by shock waves offered an unexpected change in acoustic bioimpedance , thereby contributing to plaque rupture and renal artery obstruction . however , alcohol and tobacco consumption represents the main aetiology of chronic pancreatitis , and aortic calcifications surrounding the targeted pancreatic area are therefore not infrequent in patients requiring eswl . importantly , even in patients with aortic calcifications , eswl remains the standard of care and should not be contraindicated . very few other treatment options can be proposed to patients with a large obstructive stone in the main pancreatic duct . surgery may be an alternative but is usually reserved for failures of endotherapy , since it is associated with a higher morbidity . endotherapy without eswl is not considered a valid option anymore in most recent guidelines on the management of chronic pancreatitis with obvious obstruction . mechanical lithotripsy of pancreatic stones usually fails due to the hardness of the calcified stones and is associated with a high risk of breakage of the dormia baskets used for mechanical lithotripsy . in chronic pancreatitis with radiopaque stones of 5 mm obstructing the main pancreatic duct , eswl alone is even recommended as the first - line procedure in expert centres . during pancreatic eswl in patients with extensive vascular calcifications , we would recommend limiting the shocks number ( maximum 5000 ) , the intensity of shock waves or the shock wave frequency ( < 100/min ) , to prevent vessel damage . in addition , we can not formally rule out any contributive role of aspirin withdrawal  a practice that is routinely recommended before eswl . indeed , in patients with a history of cardiovascular or cerebrovascular disease , pre - operative withdrawal of low - dose acetylsalicylic acid has been associated with an increased risk of peri - operative myocardial infarction . in patients at high vascular risk , our recommendation would be to avoid withdrawal of antiplatelet agents such as aspirin , as now recommended for other minimally invasive procedures , since eswl for pancreatic stones carries a low risk of bleeding . altogether , the renovascular nature of acute renal failure was clearly demonstrated in this case , and we speculate that eswl triggered renal artery obstruction because of surrounding extensive vascular calcifications . future epidemiological studies are required to assess the actual risk of renal failure after eswl . in the meantime , caution is warranted in patients with severe vascular calcifications that are potentially eligible for eswl .
extracorporeal shock wave lithotripsy ( eswl ) for pancreatic stones is considered a safe and efficient method to facilitate fragmentation and stone removal . 
 we describe the case of a 73-year - old woman with a solitary functioning kidney who presented an acute - onset anuria and renovascular renal failure the day after eswl . 
 we speculate that vascular calcifications in the area targeted by shock waves played a critical role in renal artery obstruction in the present case .