Effects of extracorporeal shockwave lithotripsy on renal vasculature and renal resistive index (RI).

OBJECTIVE It is known that ESWL can promote acute renal injuries and long-term complications of renal vasculature. Effects on renal vasculature can be evaluated by color Doppler ultrasonography measuring renal resistive index (RI). This prospective study aimed to determine the influence of number of delivered SW-s, used kV and changes in renal resistive index. PATIENTS AND METHODS Total of 60 normotensive patients, 38 males (63%) and 22 females (37%), with renal stones 6-18 mm in size were included in this study. Median age was 42.3 years (range 22-55). RI was measured at interlobar artery before, 1, 3, 5 and 30 days after treatment on treated and contra lateral non-treated kidney. Patients were divided in two groups: Group I (N=25) received 2000 SWs; 0-2 units; (0.5 unit each 500 SWs) Group II (N=35) received 4000 SWs, 0-4 units; (0.5 unit each 500 SWs). RESULTS In treated kidneys RI significantly increased first and second day after treatment from 0.62 +/- 0.05 at baseline to 0.67 +/- 0.05, p < 0.001 at first and 0.66 +/- 0.05, p < 0.007 on the second day after treatment. Increase of RI seven days after treatment is not significant (0.62 +/- 0.05). The contra lateral, non-treated kidney showed significant changes in RI only first day after treatment (0.64 +/- 0.05), p < 0.01. One month after the treatment RI is on normal values in both kidneys. CONCLUSIONS Resistive index-RI is important parameter in evaluation of renal vasculature. Patients treated by ESWL showed a temporary increase in RI two days after the treatment and only first day in contra lateral non-treated kidney--probably caused by release of substance with vasoconstriction properties (need further investigations).