Renal and hypertensive complications of extracorporeal shock wave lithotripsy: Who is at risk?

Extracorporeal shock wave lithotripsy (ESWL.) is now used in the treatment of about 90% of renal and ureteral stones. Because of the nonpunctual deliv ery of energy to the stone, a small volume of renal parenchyma is injured g iving place to a fibrous scar which can be shown by highly resolutive imagi ng techniques like magnetic nuclear resonance. Isotopic clearances point to a reduction of 15% in the renal plasma flow on the side of the lithotripsy , but this alteration appears to be transient in nature. In a few cases an abrupt onset of transient hypertension has been reported in clear relation to a compressive perirenal hematoma. The responsibility of ESWL in the late occurrence of permanent hypertension is, however, still uncertain, probabl y because of the difficulty in showing that this occurrence is not only rel ated to the older age of the patient. The American Food and Drug Administra tion-sponsored multicentric study begun in 1992 should solve this issue in the future. Recent articles suggest that altered renal function prior to ES WL would predict the late occurrence of hypertension and worsening of renal failure. Furthermore, age and the resistance index of arcuate or interloba r renal arteries (measured by Doppler) could help to screen patients at ris k of developing hypertension. In practice in patients over 60 years of age and/or with a plasma creatinine of >to 300 mu mol/l, ESWL should be perform ed with caution, and renal function and blood pressure should be carefully monitored. Copyright (C) 1999 S. Karger AG, Basel.