Page 2 - CUA2018 Abstracts - Endourology

Podium session 2: Pediatrics/Endourology

our cohort of infants with HN, no protective effect was seen for fUTI. for at least three months and had computed tomography scans or ultra-
CAP and etiology of the HN were the driving factors. sound imaging both prior to and post–initiation of HD. Patients with stones
antedating HD were excluded. De novo stones were defined as either
POD–2.4 symptomatic or asymptomatic calculi found on imaging. Epidemiological
data, serum analyses, and comorbidities were collected and compared
Effect of a bacterial urinary infection isolate on a calcium between stone–formers and non–stone–formers using univariate, multi-
urolithiasis model variate logistic regression analysis, and adjusted odds ratio (OR).
Jennifer Bjazevic , Kaitlin Al , Hassan Razvi , Jeremy Burton 2 Results: A total of 164 patients were included in the analysis, 42.9%
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1 Urology, Western University, London, ON, Canada; Microbiology & (n=70) of whom were females. The mean age was 67.2±15.2 years old,
Immunology, Western University, London, ON, Canada mean body mass index (BMI) was 26.5±5.8kg/m , and median dialysis
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Introduction: Urinary bacteria may contribute to the development of cal- duration was 57.1 months (range 7–201). After HD, 18 (10.9%) patients
cium stone disease. Previous epidemiological studies have demonstrated developed de novo stones and their median dialysis–to–stone duration
a correlation between culture proven urinary tract infections and stone was 23.5 month (range 7–99). The stone–former group had significantly
disease. It has also been reported in preliminary studies that bacteria have lower serum magnesium levels (0.97 vs. 0.84 mmol/L; p=0.025), higher
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been directly isolated from non–struvite stones. We aimed to examine serum uric acid levels (292.6 vs. 359.0 mmol/L; p=0.002) and lower
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the effect of non–urease producing bacteria isolated from a urinary tract 25(OH)VD levels (96.3 vs. 57.6 nmol/L; p=0.01). Additionally, 50% (n=5;
infection on the formation of calcium oxalate stones in a Drosophila p<0.001) of patients with a history of bowel resection developed stones,
melanogaster fly model. whereas only 4.1% (n=4; p=0.001) of patients with hypertension devel-
Methods: A non–urease producing strain of Escherichia coli (UTI89) was oped stones. Binary logistic regression analysis demonstrated that serum
administered to flies overnight in a 5% sucrose solution. The flies were uric acid levels (adjusted OR 1.15; 95% confidence interval [CI] 1.03–
then fed 1% sodium oxalate food for the remainder of the seven–day 1.18 for each 10 units of uric acid) and serum magnesium levels (adjusted
assay. Flies were pulverized and cultured on lysogeny broth agar plates OR 0.78; 95% CI 0.67–0.95 for each unit of magnesium) were signifi-
on Days 1–5 to determine if UTI89 persisted in the flies. Stone burden cantly associated with stone formation.
was assessed with a fecal crystal assay and survival curve analysis. Conclusions: The results of the study indicate that increased serum uric
Results: UTI89 was cultured from the exposed flies for up to three days acid levels, decreased serum magnesium levels, decreased 25(OH)VD
post–exposure with at least 3x10 colony forming units/fly. Dosing with levels and a history of bowel resection were associated with a higher
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UTI89 did not affect the survival of healthy flies fed normal food. There incidence of stone formation in ESRD HD patients. Less de novo stones
was a trend towards decreased survival in flies exposed to the combination were noted in hypertensive patients, in whom hypertension may represent
of UTI89 and oxalate food. In addition, preliminary results suggest that a surrogate for absent urine production.
exposure to UTI89 altered fecal oxalate crystal production. References:
Conclusions: These findings suggest that the presence of a non–urease 1. Daudon M, Lacour B, Jungers P, et al. Urolithiasis in patients
producing E. coli impacts calcium oxalate stone formation in a urolithiasis with end stage renal failure. J Urol 1992;147:977–80. https://doi.
model, which could have implications in human stone disease. Further org/10.1016/S0022–5347(17)37438–4
confirmation of these results is required, as well as investigation to delin- 2. Ozasa H, Ota K. Mechanism of kidney stone formation in chronic
eate the potential mechanisms by which this may occur. hemodialysis patients. Nephron 1991;58:242–3. https://doi.
References: org/10.1159/000186426
1. Holmgren K, Dalielson BG, Felsltrom B, et al. The relation
between urinary tract infections and stone composition in renal
stone formers. Scand J Urol Nephrol 1989;23:131–6. https://doi. POD–2.6
org/10.3109/00365598909180827 Double–blind, prospective, randomized clinical trial comparing
2. Tavichakorntrakool R, Prasongwattana V, Sungkeeree S, et al. regular and Moses modes of holmium laser lithotripsy:
Extensive characterizations of bacteria isolated from catheterized Preliminary results
urine and stone matrices in patients with nephrolithiasis. Nephrol Ahmed Ibrahim , Nader Fahmy , Serge Carrier , Mostafa Elhilali , Sero
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Dial Transplant 2012;27:4125–30. https://doi.org/10.1093/ndt/ Andonian 1
gfs057 1 Department of Urology, McGill University Health Centre, Montreal, QC,
3. Barr–Beare E, Saxena V, Hilt E, et al. The interaction between Canada
enterobacteriaceae and calcium oxalate deposits. PLoS One Introduction: Moses technology has been shown to improve the fragmen-
2015;10:e0139575. https://doi.org/10.1371/journal.pone.0139575 tation efficiency and reduced stone retropulsion both in in vivo and in
vitro studies. However, there are no randomized trials evaluating effec-
POD–2.5 tiveness of this new technology during laser lithotripsy. Therefore, the
objective was to compare regular and Moses modes of holmium laser
Identifying the risk factors for the development of nephrolithiasis lithotripsy in terms of stone fragmentation efficiency and perioperative
in end–stage renal disease dialysis patients complications.
Charles Hesswani , Sameena Iqbal , Kashayar Rafat Zand , Bernard Methods: After obtaining ethics approval, a prospective, double–blind,
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Unikowsky , Simon Sun , Sero Andonian 1 randomized trial was conducted for patients undergoing holmium laser
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1 Urology, McGill University Health Centre, Montreal, QC, Canada;
2 Nephrology, McGill University Health Centre, Montreal, QC, Canada; lithotripsy. Patients were randomly assigned to have holmium laser litho-
3 Radiology, McGill University Health Centre, Montreal, QC, Canada tripsy with either regular or Moses modes. Both patients and surgeons
were blinded to the laser mode. All procedures were performed by four
Introduction: There is a common assumption that patients with end–stage experienced urologists. Lumenis 120W generator with 200 Moses D/F/L
renal disease (ESRD) do not form renal stones due to their oliguric or fibers were used for all cases. Demographic data, stone parameters, peri-
anuric state. The incidence and risk factors for stone development in this operative complications, and success rates were compared. The degree of
population remain unknown. It is thought that stone formation in ESRD stone retropulsion was graded on a Likert scale from 0 (no retropulsion)
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hemodialysis (HD) patients develops via different mechanisms, therefore, to 3 (maximum retropulsion).
different risk factors may be involved in stone formation in this particular Results: A total of 66 patients were included in the study (33 per arm).
population. The aim of the present study is to assess the incidence and Both groups were comparable in terms of age, and preoperative stone
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risk factors for kidney stone development in this population. size (1.7 vs. 1.6 cm; p>0.05). When compared with the regular mode,
Methods: After obtaining ethics approval, we retrospectively reviewed Moses technology was associated with significantly lower fragmentation
the data of patients who underwent HD between 2007 and 2017 at two time (23.4 vs. 17.5 minutes; p<0.05) and total procedural time (53 vs.
tertiary care centres. We included patients who have been initiated on HD
CUAJ • June 2018 • Volume 12(6Suppl2) S55