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PD32-07 HIGH INCIDENCE OF KIDNEY STONES AFTER BARIATRIC SURGERY
THE JOURNAL OF UROLOGYâ
e838
surgeries. Compliance with medications persists as a major hurdle. Frequent LURS may have a role in preventing progression of stone disease, especially given non-compliance rates; however, this method of treatment was associated with more ER visits for renal colic. The cystinuric patient remains a challenge for the urologist and an opportunity for quality improvement. Source of Funding: None
PD32-06 ASSESSMENT OF PHARMACOLOGIC INTERVENTION ON CYSTINE STONE GROWTH USING IN VIVO IMAGING IN A MOUSE MODEL OF CYSTINURIA Jaspreet Parihar*, Kathleen Capaccione, New Brunswick, NJ; Min Yang, Derek Adler, Derek Gordon, Piscataway, NJ; Joseph Barone, New Brunswick, NJ; David Goldfarb, New York, NY; Jay Tischfield, Amrik Sahota, Piscataway, NJ INTRODUCTION AND OBJECTIVES: Slc3a1 knockout mice (KO) are a model for human cystinuria and male mice beginning at age 3 months develop urinary tract stones. Computed tomography (CT) and magnetic resonance imaging (MRI) may allow us to follow stone growth and the effects of drug treatment in live animals. We evaluated the utility of these modalities for identifying cystine stone growth in Slc3a1 KO mice and for assessing the efficacy of cystine dimethyl ester (CDME), a cystine crystal growth inhibitor. METHODS: Male mice were screened for bladder stones using the Albira CT scanner and the Aspect 2 MRI scanner. Initial bladder volume (an indicator of stone volume) was calculated using InviCRO VivoQuant software. Mice with stones were randomly assigned to treatment (200 ml of 10 mg/ml CDME, n¼11) or control (200 ml water, n¼7) groups, each given daily by gavage for 10 weeks. Volume measurements were repeated at 1-2 week intervals. Mice were then sacrificed and stone size and number analyzed using chi-square. RESULTS: 60% of mice had bladder stones. Using CT, initial bladder volumes (mm3) in both groups were similar (12-96 for control and 11-86 for CDME). In both cases, there was a linear increase in stone volume that followed the equation y¼mx+c. The equations for the CDME and the control groups were similar (range y¼0.39x+11.0 to y¼2.67x+73.3). Final MRI scans demonstrated a 15.5% and a 12.4% increase in kidney volume for the two groups, respectively, (p¼.17). Thus, the two groups could not be distinguished by CT or MRI analysis. Upon histologic evaluation there was a significant difference in the percentage of stone sizes in the two groups (p¼0.05). The treatment group had 9.4% more stones and the control group had 19.6% fewer stones in the 1.1-2.0 mm range. The treatment group had 26.1% fewer stones and the control group had 54.6% more stones in the 3.1-4.0 mm range. CONCLUSIONS: CT can determine the rate of stone growth in vivo, but longitudinal measurement of stone volume is not suitable for evaluating CDME efficacy since total stone volumes in both groups were comparable. MRI was also unable to differentiate the two groups. These imaging modalities are useful for differentiating stone formers form non-stone formers, but cannot be used for the assessment of pharmacological intervention. Source of Funding: none
PD32-07 HIGH INCIDENCE OF KIDNEY STONES AFTER BARIATRIC SURGERY John Lieske*, Ramila Mehta, Michael Sarr, Eric Bergstralh, Rochester, MN INTRODUCTION AND OBJECTIVES: Calcium oxalate kidney stones and even kidney failure secondary to oxalate nephropathy
Vol. 191, No. 4S, Supplement, Tuesday, May 20, 2014
have been described after bariatric surgery for obesity. Obesity is also a known risk factor for kidney stones. However, the relative risk of stones after bariatric surgery for obesity has not been assessed. METHODS: Patients undergoing bariatric surgery for obesity in Olmsted County, MN between 2000-2012 were identified (n¼762). All cases were matched 1:1 with non-operated Olmsted County obese controls based upon last preoperative BMI, sex, age, and year of index clinic visit or surgery. Comorbidities were assessed by electronic diagnostic codes, and laboratories for kidney stone risk factors pulled when available. RESULTS: The majority of patients had Roux en Y gastric bypass (RYGB, 93%), with the remainder having laparoscopic banding or sleeve procedures. Mean(SD) age was 44.7(11.2) for both cases and controls, with 6.0(3.2) years of follow-up available. The majority (80%) were female. BMI was 46.8(8.4) kg/m2 preoperatively for cases and 46.1(7.0) for controls. Hypertension (52.4% vs 45.8%, p¼0.01) and diabetes (27.2% vs 22.6%, p¼0.03) were slightly more common in cases. Kidney stones were prevalent in a similar number of cases (4.3%) and controls (4.2%). However, during follow-up new (incident) stones occurred in 11.0% of cases versus 4.3% of controls (P<0.001). Among cases, mean urine oxalate (when measured) was normal at <6 months (29.2(22.6) mg/24hr; n¼45) and 6-18 months (35.5(22.6) mg/24 hrs; n¼176), but elevated at >18 months from surgery (50.6(25.5) mg/ 24 hrs; n¼74). Mean CaOx SS was similarly high at all 3 time points (2.0(0.8), 1.9(0.9) and 1.8(0.9) D.G, respectively) compared to a normal value reference mean of 1.77 D.G. CONCLUSIONS: The risk of new kidney stone disease after RYGB for obesity is substantial, with approximately 10% developing a new stone by 5 years postoperatively. This risk is about double that of non-operated obese controls. Further efforts are needed to develop strategies to reduce stone events in this high risk group. Source of Funding: Mayo Clinic O’Brien Urology Research Center (U54 DK100227); the Rare Kidney Stone Consortium (U54KD083908), a member of the NIH Rare Diseases Clinical Research Network (RDCRN), funded by the NIDDK and the National Center For Advancing Translational Sciences (NCATS); and the Mayo Foundation.
PD32-08 ASSESSMENT OF REPRODUCIBILITY AND OUTOMES OF PERCUTANEOUS NEPHROSTOLITHOTOMY USING S.T.O.N.E. AND GUY’S SCORING SYSTEMS Weil Lai*, Arash Akhavein, Vincent Bird, Gainesville, FL INTRODUCTION AND OBJECTIVES: Percutaneous nephrostolithotomy (PCNL) is performed for treatment of large, complex urinary stones. Several scoring systems for predicting surgical outcome have been proposed. It is uncertain which system or individual variables are the most reproducible and can accurately predict stone clearance. We evaluate the S.T.O.N.E. nephrolithometry and Guy’s scoring systems (GSS) using pre and post operative computerized tomography CT imaging with strict criteria for stone clearance. METHODS: We analyzed a patient cohort undergoing PCNL. Inclusion criteria were primary PCNL and availability of pre- and post-operative CT imaging. Residual stone was recorded as 0-2, 34, and >4 mm. S.T.O.N.E. and GSS parameters were scored according to Okhunov et al. and Thomas et al. by two independent readers. Differences were resolved by a third reviewer. Weighted kappa values were calculated for inter-reader variability. KruskalWallis testing was used to assess significance of mean stone scores by residual stone size. Odds ratios were calculated from logistic regression. RESULTS: Analysis included 104 patients. Mean scores (interquartile range) were 9.07 (3) and 2.53 (1) for S.T.O.N.E. and GSS, respectively. Weighted kappa values for S.T.O.N.E. and GSS were 0.65
e838
surgeries. Compliance with medications persists as a major hurdle. Frequent LURS may have a role in preventing progression of stone disease, especially given non-compliance rates; however, this method of treatment was associated with more ER visits for renal colic. The cystinuric patient remains a challenge for the urologist and an opportunity for quality improvement. Source of Funding: None
PD32-06 ASSESSMENT OF PHARMACOLOGIC INTERVENTION ON CYSTINE STONE GROWTH USING IN VIVO IMAGING IN A MOUSE MODEL OF CYSTINURIA Jaspreet Parihar*, Kathleen Capaccione, New Brunswick, NJ; Min Yang, Derek Adler, Derek Gordon, Piscataway, NJ; Joseph Barone, New Brunswick, NJ; David Goldfarb, New York, NY; Jay Tischfield, Amrik Sahota, Piscataway, NJ INTRODUCTION AND OBJECTIVES: Slc3a1 knockout mice (KO) are a model for human cystinuria and male mice beginning at age 3 months develop urinary tract stones. Computed tomography (CT) and magnetic resonance imaging (MRI) may allow us to follow stone growth and the effects of drug treatment in live animals. We evaluated the utility of these modalities for identifying cystine stone growth in Slc3a1 KO mice and for assessing the efficacy of cystine dimethyl ester (CDME), a cystine crystal growth inhibitor. METHODS: Male mice were screened for bladder stones using the Albira CT scanner and the Aspect 2 MRI scanner. Initial bladder volume (an indicator of stone volume) was calculated using InviCRO VivoQuant software. Mice with stones were randomly assigned to treatment (200 ml of 10 mg/ml CDME, n¼11) or control (200 ml water, n¼7) groups, each given daily by gavage for 10 weeks. Volume measurements were repeated at 1-2 week intervals. Mice were then sacrificed and stone size and number analyzed using chi-square. RESULTS: 60% of mice had bladder stones. Using CT, initial bladder volumes (mm3) in both groups were similar (12-96 for control and 11-86 for CDME). In both cases, there was a linear increase in stone volume that followed the equation y¼mx+c. The equations for the CDME and the control groups were similar (range y¼0.39x+11.0 to y¼2.67x+73.3). Final MRI scans demonstrated a 15.5% and a 12.4% increase in kidney volume for the two groups, respectively, (p¼.17). Thus, the two groups could not be distinguished by CT or MRI analysis. Upon histologic evaluation there was a significant difference in the percentage of stone sizes in the two groups (p¼0.05). The treatment group had 9.4% more stones and the control group had 19.6% fewer stones in the 1.1-2.0 mm range. The treatment group had 26.1% fewer stones and the control group had 54.6% more stones in the 3.1-4.0 mm range. CONCLUSIONS: CT can determine the rate of stone growth in vivo, but longitudinal measurement of stone volume is not suitable for evaluating CDME efficacy since total stone volumes in both groups were comparable. MRI was also unable to differentiate the two groups. These imaging modalities are useful for differentiating stone formers form non-stone formers, but cannot be used for the assessment of pharmacological intervention. Source of Funding: none
PD32-07 HIGH INCIDENCE OF KIDNEY STONES AFTER BARIATRIC SURGERY John Lieske*, Ramila Mehta, Michael Sarr, Eric Bergstralh, Rochester, MN INTRODUCTION AND OBJECTIVES: Calcium oxalate kidney stones and even kidney failure secondary to oxalate nephropathy
Vol. 191, No. 4S, Supplement, Tuesday, May 20, 2014
have been described after bariatric surgery for obesity. Obesity is also a known risk factor for kidney stones. However, the relative risk of stones after bariatric surgery for obesity has not been assessed. METHODS: Patients undergoing bariatric surgery for obesity in Olmsted County, MN between 2000-2012 were identified (n¼762). All cases were matched 1:1 with non-operated Olmsted County obese controls based upon last preoperative BMI, sex, age, and year of index clinic visit or surgery. Comorbidities were assessed by electronic diagnostic codes, and laboratories for kidney stone risk factors pulled when available. RESULTS: The majority of patients had Roux en Y gastric bypass (RYGB, 93%), with the remainder having laparoscopic banding or sleeve procedures. Mean(SD) age was 44.7(11.2) for both cases and controls, with 6.0(3.2) years of follow-up available. The majority (80%) were female. BMI was 46.8(8.4) kg/m2 preoperatively for cases and 46.1(7.0) for controls. Hypertension (52.4% vs 45.8%, p¼0.01) and diabetes (27.2% vs 22.6%, p¼0.03) were slightly more common in cases. Kidney stones were prevalent in a similar number of cases (4.3%) and controls (4.2%). However, during follow-up new (incident) stones occurred in 11.0% of cases versus 4.3% of controls (P<0.001). Among cases, mean urine oxalate (when measured) was normal at <6 months (29.2(22.6) mg/24hr; n¼45) and 6-18 months (35.5(22.6) mg/24 hrs; n¼176), but elevated at >18 months from surgery (50.6(25.5) mg/ 24 hrs; n¼74). Mean CaOx SS was similarly high at all 3 time points (2.0(0.8), 1.9(0.9) and 1.8(0.9) D.G, respectively) compared to a normal value reference mean of 1.77 D.G. CONCLUSIONS: The risk of new kidney stone disease after RYGB for obesity is substantial, with approximately 10% developing a new stone by 5 years postoperatively. This risk is about double that of non-operated obese controls. Further efforts are needed to develop strategies to reduce stone events in this high risk group. Source of Funding: Mayo Clinic O’Brien Urology Research Center (U54 DK100227); the Rare Kidney Stone Consortium (U54KD083908), a member of the NIH Rare Diseases Clinical Research Network (RDCRN), funded by the NIDDK and the National Center For Advancing Translational Sciences (NCATS); and the Mayo Foundation.
PD32-08 ASSESSMENT OF REPRODUCIBILITY AND OUTOMES OF PERCUTANEOUS NEPHROSTOLITHOTOMY USING S.T.O.N.E. AND GUY’S SCORING SYSTEMS Weil Lai*, Arash Akhavein, Vincent Bird, Gainesville, FL INTRODUCTION AND OBJECTIVES: Percutaneous nephrostolithotomy (PCNL) is performed for treatment of large, complex urinary stones. Several scoring systems for predicting surgical outcome have been proposed. It is uncertain which system or individual variables are the most reproducible and can accurately predict stone clearance. We evaluate the S.T.O.N.E. nephrolithometry and Guy’s scoring systems (GSS) using pre and post operative computerized tomography CT imaging with strict criteria for stone clearance. METHODS: We analyzed a patient cohort undergoing PCNL. Inclusion criteria were primary PCNL and availability of pre- and post-operative CT imaging. Residual stone was recorded as 0-2, 34, and >4 mm. S.T.O.N.E. and GSS parameters were scored according to Okhunov et al. and Thomas et al. by two independent readers. Differences were resolved by a third reviewer. Weighted kappa values were calculated for inter-reader variability. KruskalWallis testing was used to assess significance of mean stone scores by residual stone size. Odds ratios were calculated from logistic regression. RESULTS: Analysis included 104 patients. Mean scores (interquartile range) were 9.07 (3) and 2.53 (1) for S.T.O.N.E. and GSS, respectively. Weighted kappa values for S.T.O.N.E. and GSS were 0.65