Renal Vascular Doppler Resistance after Extracorporeal Shock Wave Lithotripsy

Abstract

Objectives: Extracorporeal shock wave lithotripsy (ESWL) is mainly an alternative for other therapeutic methods such as surgery and endourology to treat urinary tract calculus. Although it is safe and effective, it has undesirable effects on renal function. Diagnostic techniques such as color Doppler ultrasonography create a new attitude toward renal function. The aim of this study was to evaluate renal vascular resistance change before and after extracorporeal shock wave lithotripsy. Methods: During the present study, vascular resistive index (RI) of renal intralobar artery was measured before, 30 min, and 1 week after ESWL using Doppler ultrasonography. Results: Thirty minutes after ESWL, RI was significantly increased from primary value of 0.62 +/- 0.05 to 0.66 +/- 0.06 (p = 0.0001). There was no correlation between increase of RI and patients' age. Following up the patients revealed that mean RI did not return to pretreatment level after 1 week (p < 0.05). The RI level in the old patients (3 patients who were 60 years or older) was higher than that of the younger ones (19 patients who were younger than 60 years) after 1 week (0.76 +/- 0.05 vs. 0.64 +/- 0.06). There was no meaningful relationship between ESWL voltage or number of shocks and RI variation before and after ESWL. Conclusion: Following ESWL, patients are at risk of renal tissue damage due to increase of primary RI level. Measuring RI variations using ultrasound techniques after ESWL may provide helpful information to clinical detection of renal tissue damage.