Yoo DE et al, 2012: Removal of kidney stones by extracorporeal shock wave lithotripsy is associated with delayed progression of chronic kidney disease
Yoo DE, Han SH, Oh HJ, Kim SJ, Shin DH, Lee MJ, Yoo TH, Kang SW, Choi KH.
Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
PURPOSE: This study aimed to elucidate whether stone removal by extracorporeal shock wave lithotripsy (ESWL) is associated with delayed chronic kidney disease (CKD) progression.
MATERIALS AND METHODS: We conducted a retrospective analysis of 131 nephrolithiasis patients with stage 3 and 4 CKD. We collected baseline clinical and laboratory data, kidney stone characteristics, and history of receiving ESWL. We classified study patients into two groups according to whether they underwent ESWL or not (Non-ESWL group vs. ESWL group). We initially compared annual estimated glomerular filtration rate (eGFR) changes of Non-ESWL group with those of ESWL group before undergoing ESWL. In the next step, we sought to compare annual eGFR changes in the same patients before and after ESWL. Finally, we compared annual eGFR changes between success and failure groups among patients undergoing ESWL.
RESULTS: The mean age of the patients was 62 years and 72.5% were male. The mean observation period was 3.2 years. Non-ESWL group and ESWL group before undergoing ESWL showed similar annual eGFR changes (-1.75±6.5 vs. -1.63±7.2 mL/min/1.73 m2/year, p=0.425). However, eGFR declined slower after undergoing ESWL than before ESWL (annual eGFR changes, -0.29±6.1 vs. -1.63±7.2 mL/min/1.73 m2/year, p<0.05). In addition, among patients in ESWL group, eGFR declined faster in the failure group than in the success group (annual eGFR change, -1.01±4.7 vs. -0.05±5.2 mL/min/1.73 m2/year, p<0.05).
CONCLUSION: Our results suggest that stone removal by ESWL is associated with delayed deterioration of renal function in CKD patients with nephrolithiasis.
Yonsei Med J. 2012 Jul 1;53(4):708-14. doi: 10.3349/ymj.2012.53.4.708.
PMID: 22665335 [PubMed - indexed for MEDLINE] PMCID: PMC3381494
SWL-treatment of patients with reduced renal function is a matter of concern and it has been generally considered that shock wave trauma to the renal tissue might further deteriorate the already poor kidney function (a problem that is illustrated also in the animal studies reported in the article by Gecit at al). It is difficult to see what we can learn from this report of in total 131 patients with chronic kidney disease (low estimated GFR), 34 of who were treated with SWL because of stones in one or both kidneys. The reasons for treating these patients are, however, not obvious, but it can be assumed that the essential purpose was to eliminate an obstructive element of the disease. Whether some degree of obstruction or risk of intermittent obstruction was present in the non-SWL patients is not known. Details of the stone situation apart from size and number of stones are not given in the article. In the light of these findings it might be concluded that SWL of stones in the kidney is not associated with an increased risk of further deterioration. In contrast to what can be expected the treatment can result in more favourable course of the kidney disease. This finding is interesting since the patients were treated with in average 2 sessions and 3000 shock waves per stone.
Despite these reassuring results there was a 3% occurrence of renal hematoma and 6% of the patients had ureteral obstruction requiring additional measures. It might have been an even better outcome if an internal stent had been inserted before the SWL treatment of these risk patients.