[Changes in renal blood flow after treatment with ESWL in patients with renal stones. Studies using ultrasound color Doppler method].

Recently several authors have observed tissue damages in ESWL treated kidneys, such as interstitial hemorrhage and edema, cavitation of renal tubular cells and vascular spasms. Examination using renal scintigraphy suggested that these damages could cause a decrease of renal blood flow in the treated kidney. Trying to confirm and further investigate this possibility, we studied on changes of renal blood flow velocity using ultrasound color doppler method in 23 consecutive patients with renal stones who underwent ESWL. The studies were conducted before, immediately after and 1 week after an ESWL treatment. Results were as follows; renal blood flow velocity decreased significantly in the area exposed to shock were immediately after the treatment and returned to the pretreatment levels after 1 week. The changes were not significant in the non-exposed area. In parallel with this decrease of renal blood flow velocity, significant increases of resistive index, pulsatility index and significant decreases of ratio were observed. These parameters calculated by measuring of renal blood flow velocity are known to well correlate with parenchymal vascular resistance. We speculate that these changes in renal parenchymal blood flow velocity are triggered by the tissue damages caused by the exposure to shock wave. The recovery of renal blood flow velocity may depend on the recovery of the tissue damages. Ultrasound color doppler method may make it possible to monitor the recovery of tissue damages induced by shock wave and may provide us with an useful information to determine when to repeat ESWL if needed.