Presentation Authors: Chi-Fai Ng*, Chi Hang Yee, Jeremy Teoh, Steven Leung, Becky Lau, Wong Ka Tak, Winnie Chu, Hong Kong, Hong Kong
Introduction: To assess the effects of voltage escalation in patients receiving SWL for renal stones, particularly on treatment success and degree of renal injury, in term of post-SWL haematoma and also change in urinary level of acute renal injury markers.
Methods: During Februray 2016 and June 2018, 300 patients with renal stones were prospectively randomised to receive shockwave delivered at either voltage escalation (Group-1) or constant voltage (Group-2) in a single institute using Modulith SLX-F2 for maximum 3000 shocks at 1.5Hz. Primary outcome was successful treatment at 12-weeks after one session of lithotripsy, as defined as stone free or stone fragment < 4mm on computerized tomography. Secondary outcome measures included stone free rate, incidence of perinephric haematoma, as access by post-treatment imaging, and also changes in urinary level of acute renal injury markers.
Results: There were 300 patients, with 150 patients in each group, were recruited for the study. The mean stone size for Group-1 and -2 were 8.9 mm and 9.1 mm respectively (p=0.201). There was no difference between the other baseline parameters of the two groups. Group-1 has received lower energy shockwaves (p < 0.001) than Group-2. The overall treatment success rate and stone free rate was 70.7% and 39.4% respectively, and there was no difference observed between the two groups. The number of patients develop perinephric haematoma, as detected by cross-sectional imaging on Day-2 after SWL, for Group-1 & Group-2 were 23.8% and 43.8% respectively (p < 0.001). Both groups had similar unplanned hospital admission rate. There was a statistically significant rise in urinary N-acetyl-beta-D-glucosaminidase, interleukin-18, KIM-1 and albumin level in both groups after SWL. However, there was no between-group difference in the urinary markers level. All markers level returned to baseline level at 6 weeks after SWL.
Conclusions: When compared to constant voltage SWL, voltage escalation could provide similar stone free and treatment successful rate for renal stone less than 15mm. However, it could significantly decrease the incidence of post-SWL perinephric haematoma.
Source of Funding: Hong Kong General Research Fund Project number 14113515