Effects of Multiple Sequential Extracorporeal Shock Wave Treatments on Renal Function: A Primate Model

As extracorporeal shock wave lithotripsy (SWL) has been used for stones of increasing size, there has emerged a need for multiple treatments to fragment the stone adequately, and there has been some concern about the effect of these sequential treatments on renal function. No long-term studies are available as to the timing of a second or third treatment, nor of the effects on the individual kidney. We used six adult Rhesus monkeys (Macaca mulatta). The first group (N = 3) was treated with 2500 shocks at 28 kV to one kidney and the next group (N = 3) was treated with 2000 shocks at 18 kV at weekly intervals for 3 weeks. The animals were followed with quantitative renal camera studies prior to treatment, 48 hours after treatment, then weekly for 3 weeks, at 3 months, and at 6 months. The animals in the single-treatment group had a change in effective renal plasma flow (ERPF) of 2 ml/min per m², which was equal to baseline (P > 0.1). In the multiple treatment group, there was a slight rise of ERPF (1 ml/min per m²) which was likewise equal to baseline (P > 0.1). Comparing the two groups, the ERPF data were equivalent. Urinary lactic dehydrogenase was elevated immediately after treatment, indicating some degree of tissue trauma, and returned to baseline by 3 weeks. One animal in the single-treatment group died from renal hemorrhage the day after treatment. Multiple SWL treatments spaced approximately 1 week apart have no apparent untoward effect on renal function compared with single high-dose treatment.