Reimagining Ambulatory Care in Urology: Conversion of the Urology Clinic into a Procedure Center Improves Patient's Experience.

Introduction: The coronavirus disease 2019 (COVID-19) pandemic made it necessary to practice social distancing and limited in-person encounters in health care. These restrictions created alternative opportunities to enhance patient access to care in the ambulatory setting. We hypothesized that by transforming clinics into centers that prioritize procedures and transitioning ambulatory appointments to telehealth, we could establish a secure, streamlined, and productive method for providing patient care. Methods: Clinic templates were restructured to allow the use of the physical space to perform procedure-based clinics exclusively, while switching to virtual telemedicine for all nonprocedural encounters. Staff members were given specific roles to support one of the patient care modalities for a given day (Procedures vs. Telehealth). Performance and patient satisfaction metrics were collected between two periods of time defined as P1 (February-June 2019) and P2 Post-COVID (February-June 2020) and compared. These served as proxies of periods when the clinic workflow and templates were structured in the traditional versus the emerging way. Statistical analysis was performed using bivariate analyses. Results: The percentage of procedures performed among all in-person visits were higher in P2 compared to P1 (45% vs. 29%, p < 0.001). Although total charges and relative value units were lower in P2, the overall revenue generated was higher compared to P1 ($4,597,846 vs. $4,517,427$, respectively). This increase in revenue was mainly driven by the higher relative income generated by procedures. Patient experience, reflected through patient-reported outcomes, was more favorable in P2 where patients seemed more likely to "Recommend this provider office" (90% vs. 85.7%, p = 0.01), report improved "Access overall" (56% vs. 49%, p = 0.02), and felt they were "Moving through your visit overall" (59% vs. 51%, p = 0.007). Conclusions: Our data suggest that reorganizing urology clinics into a space that is centered around outpatient procedures can represent a model that improves the patient's access to care and clinical experience, while simultaneously improving operational financial strength. This efficient care model could be considered for many practice settings and drive high-value outpatient care.

Comparison of Minimally Invasive Procedures for Benign Prostatic Hyperplasia: A Cost-effectiveness Analysis.

Background Benign prostatic hyperplasia (BPH) is a disease that affects millions of U.S. men and is costly to treat. Purpose To compare the cost-effectiveness of four minimally invasive therapies (MITs) and medical management for the treatment of BPH. Materials and Methods A cost-effectiveness analysis from a payer's perspective with Markov modeling was performed, comparing prostatic artery embolization (PAE), prostatic urethral lift, aquablation, water vapor thermal therapy, and medical management for BPH spanning a time horizon of 5 years. The model incorporated the probability of procedural complications and recurrent symptoms necessitating retreatment, which were extracted from published studies with long-term follow-up. Costs were based on Medicare reimbursements using CPT codes for ambulatory surgery centers. Outcomes were measured using the quality-adjusted life year (QALY), incorporating both life quality and expectancy. Statistical analyses included a base case calculation (using the most probable value of each parameter) and probabilistic and deterministic sensitivity analyses. Results In the base case calculation, outcomes for the strategies were comparable, with a difference of 0.030 QALY (11 days of life in perfect health) between the most (PAE) and least (medical management) effective strategies. PAE was the most cost-effective strategy relative to medical management, with an incremental cost-effectiveness ratio of $64 842 per QALY. Probabilistic sensitivity analysis showed PAE was more cost-effective compared with prostatic urethral lift, aquablation, water vapor therapy, and medical management in pairwise comparisons. In sensitivity analysis of retreatment risk, PAE remained the most cost-effective strategy until its repeat treatment rates exceeded 2.30% per 6 months, at which point water vapor therapy became the optimal choice. PAE was the most cost-effective procedure when its procedural cost was lower than $4755. Aquablation and prostatic urethral lift became more cost-effective when their procedural costs were lower than $3015 and $1097, respectively. Conclusion This modeling-based study showed that PAE appears to be a cost-effective modality among medical management and MITs for patients with BPH, with comparable outcomes to prostatic urethral lift, water vapor therapy, and aquablation at a lower expected cost. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.

Maternal family history of urolithiasis is associated with earlier age of onset of stone disease.

PURPOSE: To evaluate the impact of detailed family history on the severity of disease and age of onset in patients with urolithiasis. METHODS: Prospectively collected data from a single institution between October 2015 and December 2020 were analyzed. Our primary endpoint was the number of patients experiencing at least one recurrent stone during the follow-up period. RESULTS: Of 1566 patients analyzed, 603 (39%) reported at least one family member with a history of stones. The percentage of patients experiencing at least one recurrent stone event was higher in patients with a family history of stones (38%) compared to those without a family history of stones (28%) over a median follow-up period of 8 months (p = 0.001). On multivariate analysis, the presence of any family history of urolithiasis increased risk of recurrent stone events (odds ratio [OR] 1.62, p < 0.001). The presence of both a first- and a second-degree relative with urolithiasis was associated with higher odds for a recurrent stone event (OR 2.17; p = 0.003) and a younger age of onset for stones, (OR 3.32; < 0.001). A maternal-side relative with stones conferred a higher odds ratio for younger age of first onset of stones (OR 2.93; p < 0.001). CONCLUSION: Any family history of kidney stone disease imparts an increased risk of recurrent stone event and an earlier age of onset for urolithiasis. The presence of both first- and second-degree relatives or a maternal-side relative with kidney stones may be a predictor for an earlier age of onset for urolithiasis.

Clinical and postoperative characteristics of stentless ureteroscopy patients: a prospective analysis from ReSKU.

INTRODUCTION: To evaluate the clinical characteristics as well as the postoperative course of urolithiasis patients undergoing a ureteroscopy (URS) without stent placement. MATERIALS AND METHODS: This was a prospective case cohort study utilizing data collected in the Registry for Stones of the Kidney and Ureter (ReSKU) from a single institution between October 2015 and December 2020. We identified all consecutive patients undergoing URS for stone disease and analyzed data encompassing demographics, medical history, intra and postoperative characteristics, including complications and postoperative symptoms. Univariate and multivariate logistic regression analyses were performed based on the presence or absence of an indwelling ureteral stent. RESULTS: A total of 470 patients were included for analysis, 92 patients in the stentless group (19.5%). Factors associated with stentless ureteroscopy were a lower stone burden (p < 0.001), the pre-existence of a ureteral stent (37.4% vs. 27.9% p = 0.011), absence of an access sheath (14.6% vs. 69.5% p < 0.001), and a shorter operative time (31 vs. 58 min p < 0.001). Postoperative gross hematuria and lower urinary tract symptoms (LUTS) were reported less frequently in stentless patients (p = 0.02, p = 0.01, respectively). There was no difference in postoperative complications between both groups (15.2% vs. 12.0%, p = 0.385). On multivariate analysis, the risk of postoperative complications was associated with obesity, stone burden ≥ 1 cm, and positive preoperative urine culture. There was no patient who required emergent stent placement in the stentless group. CONCLUSION: Our data show that, in well selected patients, omitting ureteral stent placement after URS can decrease postoperative gross hematuria and LUTS without increasing postoperative complications.

A conserved role of the insulin-like signaling pathway in diet-dependent uric acid pathologies in Drosophila melanogaster.

Elevated uric acid (UA) is a key risk factor for many disorders, including metabolic syndrome, gout and kidney stones. Despite frequent occurrence of these disorders, the genetic pathways influencing UA metabolism and the association with disease remain poorly understood. In humans, elevated UA levels resulted from the loss of the of the urate oxidase (Uro) gene around 15 million years ago. Therefore, we established a Drosophila melanogaster model with reduced expression of the orthologous Uro gene to study the pathogenesis arising from elevated UA. Reduced Uro expression in Drosophila resulted in elevated UA levels, accumulation of concretions in the excretory system, and shortening of lifespan when reared on diets containing high levels of yeast extract. Furthermore, high levels of dietary purines, but not protein or sugar, were sufficient to produce the same effects of shortened lifespan and concretion formation in the Drosophila model. The insulin-like signaling (ILS) pathway has been shown to respond to changes in nutrient status in several species. We observed that genetic suppression of ILS genes reduced both UA levels and concretion load in flies fed high levels of yeast extract. Further support for the role of the ILS pathway in modulating UA metabolism stems from a human candidate gene study identifying SNPs in the ILS genes AKT2 and FOXO3 being associated with serum UA levels or gout. Additionally, inhibition of the NADPH oxidase (NOX) gene rescued the reduced lifespan and concretion phenotypes in Uro knockdown flies. Thus, components of the ILS pathway and the downstream protein NOX represent potential therapeutic targets for treating UA associated pathologies, including gout and kidney stones, as well as extending human healthspan.

Long-Term Antibiotic Treatment Prior to Laparoscopic Nephrectomy for Xanthogranulomatous Pyelonephritis Improves Postoperative Outcomes: Results from a Multicenter Study.

PURPOSE: Xanthogranulomatous pyelonephritis is a destructive bacterial infection typically necessitating nephrectomy. We hypothesized that long-term preoperative antibiotics would facilitate laparoscopic nephrectomy by reducing the renal inflammation. MATERIALS AND METHODS: We reviewed the records of all patients with histologically confirmed xanthogranulomatous pyelonephritis at 3 University of California institutions between 2005 and 2018. Patients were stratified by antibiotic treatment duration and surgical approach. Patients treated with long-term preoperative antibiotics (28 days or more of continuous treatment until surgery) were compared to patients treated with short-term antibiotics (less than 28 days) and those who only received single-dose prophylactic antibiotics before surgery. Patient demographics and operative outcomes were analyzed. Complications were assigned by Clavien-Dindo classification. RESULTS: Among the 61 patients, 51 (84%) were female and mean age was 50 years. There were 21 (34%) open procedures and 40 (66%) laparoscopic procedures. Median duration of antibiotic treatment was 5 days in those who received a short-term treatment and 87 days in those who received long-term treatment. Eleven patients received only prophylactic single-dose antibiotics. Using multivariate analysis among patients undergoing laparoscopic nephrectomy, controlling for preoperative drainage, long-term antibiotics resulted in a 6.5-day shorter length of stay (p=0.023) and less overall as well as milder postoperative complications (p <0.001). CONCLUSIONS: Greater than or equal to 4 weeks of preoperative antibiotics before laparoscopic nephrectomy for xanthogranulomatous pyelonephritis was associated with shorter length of stay and fewer, less severe postoperative complications.

Estimating the health-related quality of life of kidney stone patients: initial results from the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA).

OBJECTIVE: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones. MATERIAL AND METHODS: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC). RESULTS: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age. CONCLUSIONS: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications.

Fatty acid-binding protein 4 downregulation drives calcification in the development of kidney stone disease.

Nephrolithiasis is a significant source of morbidity, and its incidence has increased significantly over the last decades. This rise has been attributed to concurrent increasing rates of obesity, associated with a 3-time risk of developing NL. To date, the mechanism by which obesity is linked to stone formation has not been elucidated. We aimed to utilize a transcriptomics approach to discover the missing link between these two epidemic diseases. We investigated gene expression profiling of nephrolithiasis patients by two RNA-sequencing approaches: comparison between renal papilla tissue with and without the presence of calcified Randall's plaques (RP), and comparison between the papilla, medulla, and cortex regions from within a single recurrent stone forming kidney. Results were overlaid between differently expressed genes found in the patient cohort and in the severely lithogenic kidney to identify common genes. Overlay of these two RNA-sequencing datasets demonstrated there is impairment of lipid metabolism in renal papilla tissue containing RP linked to downregulation of fatty acid binding protein (FABP) 4. Immunohistochemistry of human kidney specimens and microarray analysis of renal tissue from a nephrolithiasis mouse model confirmed that FABP4 downregulation is associated with renal stone formation. In a FABP4 knockout mouse model, FABP4 deficiency resulted in development of both renal and urinary crystals. Our study revealed that FABP4 plays an important, previously unrecognized role in kidney stone formation, providing a feasible mechanism to explain the link between nephrolithiasis and metabolic syndrome.

Thiel-embalmed cadavers as a novel training model for ultrasound-guided supine endoscopic combined intrarenal surgery.

OBJECTIVE: To evaluate Thiel-embalmed cadavers (TEC) as a training model for percutaneous nephrolithotomy (PCNL), more specifically for ultrasound (US)-guided supine endoscopic combined intrarenal surgery (ECIRS). SUBJECTS AND METHODS: Thirteen urologists (nine experienced endourologists, four fellows/residents) performed an US-guided supine ECIRS procedure on a TEC. The model was evaluated by way of a questionnaire (5-point Likert scale). Descriptive statistical analysis was performed and results were graphically presented using divergent bar graphs. RESULTS: US images were appreciated as lifelike in all aspects. Although distention of the collecting system was not ideal in one out of three TEC, US visualisation of the distended calyces during puncture was good. Skin penetration was more difficult and less realistic in TEC, while kidney puncture and dilatation were deemed very realistic. Ureteric and collecting system anatomy and consistency were similar to real life, although the mucosa appeared paler. US needle guidance was perceived as excellent. Overall, needle puncture assessment was realistic and useful as a training tool. Overall quality and satisfaction of TEC in US-guided supine ECIRS was good to excellent and comparable to a real-life procedure. Overall appropriateness of the TEC model was considered excellent for both initial and advanced supine PCNL training. CONCLUSION: Despite the minor drawbacks of tough skin and non-ideal collecting system dilatation during ureteroscopy, the TEC model was considered good to excellent as a training model for US-guided PCNL, in particular, US-guided needle puncture of the kidney during supine ECIRS.

Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy.

OBJECTIVES: To compare clinical outcomes in patients who underwent percutaneous nephrolithotomy (PCNL) with renal tract dilatation performed under fluoroscopic guidance vs renal tract dilatation with ultrasound guidance. PATIENTS AND METHODS: We conducted a prospective observational cohort study, enrolling successive patients undergoing PCNL between July 2015 and March 2018. Included in this retrospective analysis were cases where the renal puncture was successfully obtained with ultrasound guidance. Cases were then grouped according to whether fluoroscopy was used to guide renal tract dilatation or not. All statistical analyses were performed using Stata version 15.1 including univariate (Fisher's exact test, Welch's t-test) and multivariate analyses (binomial logistic regression, ordinal logistic regression, and linear regression). RESULTS: A total of 176 patients underwent PCNL with successful ultrasonography-guided renal puncture, of whom 38 and 138 underwent renal tract dilatation with fluoroscopic vs ultrasound guidance, respectively. There were no statistically significant differences in patient age, gender, body mass index (BMI), preoperative hydronephrosis, stone burden, procedure laterality, number of dilated tracts, and calyceal puncture location between the two groups. Among ultrasound tract dilatations, a higher proportion of patients were placed in the modified dorsal lithotomy position as opposed to prone, and a significantly shorter operating time was observed. Only modified dorsal lithotomy position remained statistically significant after multivariate regression. There were no statistically significant differences in postoperative stone clearance, complication rate, or intra-operative estimated blood loss. A 5-unit increase in a patient's BMI was associated with 30% greater odds of increasingly severe Clavien-Dindo complications. A 5-mm decrease in the preoperative stone burden was associated with 20% greater odds of stone-free status. No variables predicted estimated blood loss with statistical significance. CONCLUSIONS: Renal tract dilatation can be safely performed in the absence of fluoroscopic guidance. Compared to using fluoroscopy, the present study demonstrated that ultrasonography-guided dilatations can be safely performed without higher complication or bleeding rates. This can be done using a variety of surgical positions, and future studies centred on improving dilatation techniques could be of impactful clinical value.

Non-radiological assessment of kidney stones using the kidney injury test (KIT), a spot urine assay.

OBJECTIVES: To evaluate the utility of kidney injury test (KIT) assay urinary biomarkers to detect kidney stones and quantify stone burden. PATIENTS AND METHODS: A total of 136 spot urine samples from 98 individuals, with and without kidney stone disease, were processed in a predefined assay to measure six DNA and protein markers in order to generate a risk score for the non-invasive detection of nephrolithiasis. From this cohort, 56 individuals had spot, non-timed urine samples collected at the time of radiographically confirmed kidney stones, and 54 demographically matched, healthy controls without kidney stone disease also provided spot, non-timed urine samples. Sixteen individuals with persistent stone disease had more than one urine sample. Using a proprietary microwell-based KIT assay, we measured cell-free DNA (cfDNA), methylated cfDNA, clusterin, creatinine, protein and CXCL10. A KIT stone score was computed across all markers using the prior locked KIT algorithm. The KIT stone score, with a scale of 0 to 100, was then correlated with demographic variables, kidney stone burden, obstructive kidney stone disease, and urine solutes in 24-h urine collections. RESULTS: The scaled KIT stone score, a composite of all six biomarkers, readily discriminated individuals with current or prior radiographically confirmed kidney stones from healthy controls without kidney stone disease (P < 0.001). In individuals with nephrolithiasis, KIT stone score also correlated with radiologically measured stone size (P = 0.017) and differentiated patients with a clinical radiological diagnosis of obstructive nephrolithiasis associated with upper renal tract dilatation (P = 0.001). Stone burden as assessed by KIT stone score, however, did not correlate with the any of the traditional measures of 24-h urine solutes or the 24-h urine supersaturation levels. In patients with persistent stone disease, where multiple urine samples were collected over time and after different interventions, the use of KIT stone score could non-invasively track stone burden over time through a spot urine, non-timed urine sample. CONCLUSIONS: A random, spot urine-based assay, KIT stone score, can non-invasively detect, quantify and monitor current stone burden, and may thus minimize radiographic exposure for kidney stone detection. The KIT stone score assay may also help monitor stone recurrence risk for patients with nephrolithiasis, without the requirement for 24-h urine collections.

Association of Patient Age and Gender with Kidney Stone Related Quality of Life.

PURPOSE: Kidney stone formers have lower health related quality of life than nonstone formers. The North American Stone Quality of Life Consortium is a multicenter, longitudinal, prospective study of health related quality of life in patients with kidney stones using the WISQOL (Wisconsin Stone Quality of Life Questionnaire) with data on 2,052 patients from a total of 11 centers. This study is a subanalysis of cross-sectional data looking at the association of age, gender and race on health related quality of life of stone formers. MATERIALS AND METHODS: We performed multivariable analyses of ordinal logistic regression analyses to determine the impact of age, gender and race on health related quality of life, adjusting for other baseline covariates. The proportional odds assumption of ordinal logistic regression was checked. Total score and scores on 4 subdomains (social functioning, emotional functioning, stone related impact and vitality) were included. RESULTS: Median total score for all patients was 80.4. On multivariable analysis older patients had a significantly higher total health related quality of life score than younger patients (per 10-year increase OR 1.25, p <0.0001). Male patients had higher scores than females (OR 1.56, p = 0.0003) and nonCaucasian patients had lower health related quality of life than nonLatino Caucasian patients (OR 0.63, p = 0.0045). CONCLUSIONS: Younger and female patients with kidney stones have lower health related quality of life than older and male patients, respectively. NonCaucasian patients with stones also have lower health related quality of life. The clinical impact of these findings might include future implications for patient counseling, including dietary and medical management of stone disease, and potential changes to the paradigm of the surgical management of stones.

Low Income and Nonwhite Race are Strongly Associated with Worse Quality of Life in Patients with Nephrolithiasis.

PURPOSE: Kidney stones are a source of significant morbidity which have been shown to negatively impact health related quality of life. We sought to understand the association between health related quality of life, socioeconomic status and race among patients with kidney stones. MATERIALS AND METHODS: Patients with stones at a total of 11 stone centers across the United States completed the WISQOL (Wisconsin Stone Quality of Life questionnaire). The patient ZIP Code™ was used to estimate household income. A mixed effects regression model was constructed for analysis with ZIP Code as the random intercept. RESULTS: A total of 2,057 stone formers completed the WISQOL. Lower income was independently associated with significantly lower health related quality of life (ß = 0.372, p = 0.014), as were nonwhite race (ß = -0.299, p = 0.001), unemployed work status (ß = -0.291, p = 0.008), female gender (ß = -0.204, p <0.001), body mass index greater than 40 kg/m2 (ß = -0.380, p <0.001), 5 or more medical comorbidities (ß = -0.354, p = 0.001), severe recurrent stone formation (ß = -0.146, p = 0.045), enrollment at an acute care visit, or a preoperative or postoperative appointment (ß = -0.548, p <0.001) and recent stone symptoms (ß = -0.892, p <0.001). CONCLUSIONS: Lower income, nonwhite race and unemployed work status were independently associated with lower health related quality of life among patients with kidney stones. While clinical characteristics such as body mass and stone disease severity were also associated with health related quality of life, this study shows that socioeconomic factors are similarly important. Further research to understand the specific mechanisms by which socioeconomic status and race impact health may lend insight into methods to optimize clinical treatment of stone formers and patients with other chronic diseases.

Feasibility of Antegrade Contrast-enhanced US Nephrostograms to Evaluate Ureteral Patency.

Purpose To demonstrate the feasibility of contrast material-enhanced ulrasonographic (US) nephrostograms to assess ureteral patency after percutaneous nephrolithotomy (PCNL) in this proof-of-concept study. Materials and Methods For this HIPAA-compliant, institutional review board-approved prospective blinded pilot study, patients undergoing PCNL provided consent to undergo contrast-enhanced US and fluoroscopic nephrostograms on postoperative day 1. For contrast-enhanced US, 1.5 mL of Optison (GE Healthcare, Oslo, Norway) microbubble contrast agent solution (perflutren protein-type A microspheres) was injected via the nephrostomy tube. Unobstructed antegrade ureteral flow was defined by the presence of contrast material in the bladder. Contrast-enhanced US results were compared against those of fluoroscopic nephrostograms for concordance. Results Ten studies were performed in nine patients (four women, five men). Contrast-enhanced US demonstrated ureteral patency in eight studies and obstruction in two. One patient underwent two studies, one showing obstruction and the second showing patency. Concordance between US and fluoroscopic assessments of ureteral patency was evaluated by using a Clopper-Pearson exact binomial test. These results were perfectly concordant with fluoroscopic nephrostogram results, with a 95% confidence interval of 69.2% and 100%. No complications or adverse events related to contrast-enhanced US occurred. Conclusion Contrast-enhanced US nephrostograms are simple to perform and are capable of demonstrating both patency and obstruction of the ureter. The perfect concordance with fluoroscopic results across 10 studies demonstrated here is not sufficient to establish diagnostic accuracy of this technique, but motivates further, larger scale investigation. If subsequent larger studies confirm these preliminary results, contrast-enhanced US may provide a safer, more convenient way to evaluate ureteral patency than fluoroscopy. © RSNA, 2016 Online supplemental material is available for this article.

Emergency Department Imaging Modality Effect on Surgical Management of Nephrolithiasis: A Multicenter, Randomized Clinical Trial.

PURPOSE: In the emergency department ultrasonography is emerging as an alternative to computerized tomography for diagnosing patients with nephrolithiasis. In this multicenter randomized clinical trial we examined rates of urological referral and intervention to elucidate whether the initial diagnostic imaging modality affected the management of nephrolithiasis. MATERIALS AND METHODS: Patients 18 to 76 years old who presented to the emergency department with renal colic across 15 diverse treatment centers were randomized to receive abdominal ultrasonography by an emergency department physician or a radiologist, or abdominal computerized tomography. We analyzed the 90-day followup for patients diagnosed with nephrolithiasis to assess subsequent urological evaluation, procedure type and time to intervention. RESULTS: Of 1,666 patients diagnosed with nephrolithiasis in the emergency department 241 (14.5%) had a consultation with urology at initial presentation, 503 (30%) saw a urologist in followup and 192 (12%) underwent at least 1 urological procedure. Median time to outpatient procedure and type of procedure performed did not vary significantly among imaging groups. Most patients (78%) had computerized tomography performed before elective intervention. Patients with ultrasonography performed by an emergency department physician were 2.6 times more likely to undergo computerized tomography before intervention than those who had ultrasonography performed by a radiologist. CONCLUSIONS: Patients undergoing a urological intervention who had ultrasonography as initial imaging do not experience a significant delay to intervention or different procedure types, but the majority ultimately undergoes computerized tomography before surgery. Formal ultrasonography by a radiologist may encourage less computerized tomography preoperatively.

Contrast Enhanced Ultrasound as a Radiation-Free Alternative to Fluoroscopic Nephrostogram for Evaluating Ureteral Patency.

PURPOSE: We compared contrast enhanced ultrasound and fluoroscopic nephrostography in the evaluation of ureteral patency following percutaneous nephrolithotomy. MATERIALS AND METHODS: This prospective cohort, noninferiority study was performed after obtaining institutional review board approval. We enrolled eligible patients with kidney and proximal ureteral stones who underwent percutaneous nephrolithotomy at our center. On postoperative day 1 patients received contrast enhanced ultrasound and fluoroscopic nephrostogram within 2 hours of each other to evaluate ureteral patency, which was the primary outcome of this study. RESULTS: A total of 92 pairs of imaging studies were performed in 82 patients during the study period. Five study pairs were excluded due to technical errors that prevented imaging interpretation. Females slightly predominated over males with a mean ± SD age of 50.5 ± 15.9 years and a mean body mass index of 29.6 ± 8.6 kg/m2. Of the remaining 87 sets of studies 69 (79.3%) demonstrated concordant findings regarding ureteral patency for the 2 imaging techniques and 18 (20.7%) were discordant. The nephrostomy tube was removed on the same day in 15 of the 17 patients who demonstrated antegrade urine flow only on contrast enhanced ultrasound and they had no subsequent adverse events. No adverse events were noted related to ultrasound contrast injection. While contrast enhanced ultrasound used no ionizing radiation, fluoroscopic nephrostograms provided a mean radiation exposure dose of 2.8 ± 3.7 mGy. CONCLUSIONS: A contrast enhanced ultrasound nephrostogram can be safely performed to evaluate for ureteral patency following percutaneous nephrolithotomy. This imaging technique was mostly concordant with fluoroscopic findings. Most discordance was likely attributable to the higher sensitivity for patency of contrast enhanced ultrasound compared to fluoroscopy.

Dietary Zinc and Incident Calcium Kidney Stones in Adolescence.

PURPOSE: We determined the association between dietary zinc intake and incident calcium kidney stones in adolescents. We also examined the relationship between dietary zinc intake and urinary zinc excretion between cases and controls. MATERIALS AND METHODS: We conducted a nested case-control study within a large pediatric health care system. Three 24-hour dietary recalls and spot urine chemistry analyses were obtained for 30 participants 12 to 18 years old with a first idiopathic calcium based kidney stone and 30 healthy controls matched for age, sex, race and month of enrollment. Conditional logistic regression models were used to estimate the association between daily zinc intake and incident calcium kidney stones, adjusting for dietary phytate, protein, calcium, sodium and oxalate. Multivariable linear regression was used to estimate the association between dietary and urine zinc, adjusting for urine creatinine and dietary phytate and calcium. RESULTS: Cases had lower daily zinc intake (8.1 mg) than controls (10 mg, p = 0.029). Daily zinc intake of boys and girls with calcium stones was 2 mg and 1.2 mg less, respectively, than the daily intake recommended by the Institute of Medicine. Odds of incident stones were reduced by 13% for every 1 mg increase in daily zinc intake (OR 0.87, 95% CI 0.75-0.99). There was an estimated 4.5 µg/dl increase in urine zinc for every 1 mg increase in dietary zinc (p = 0.009), with weak evidence of a smaller increase in urine zinc in cases than in controls (interaction p = 0.08). CONCLUSIONS: Decreased dietary zinc intake was independently associated with incident calcium nephrolithiasis in this population of adolescents.

Medical expulsive therapy use in emergency department patients diagnosed with ureteral stones.

OBJECTIVE: Recent studies have clarified the role of alpha-blockers, such as tamsulosin, for patients diagnosed with ureteral stones <10mm not requiring an urgent intervention. Prior studies have reported low rates of use of MET by emergency physicians. We sought to describe patterns of alpha-blocker use and to determine factors associated with utilization in patients diagnosed with ureterolithiasis in the ED. METHODS: We used data from a randomized trial of CT scan vs. ultrasound in participants with suspected urolithiasis enrolled at 15 EDs between October 2011 and February 2013. The use of medical expulsive therapy was identified by the prescription of an alpha-blocker, calcium channel blocker, or steroid at the ED visit. The prevalence of alpha-blocker use in participants with ureteral stones on imaging was calculated, and multivariable models were used to examine risk factors for utilization. RESULTS: Of the 524 participants who were identified with a ureteral stone on CT scan and discharged from the ED, 375 (71.4%) received an alpha-blocker, and 2 (<1%) received a steroid. There was no significant difference in alpha-blocker use for participants based on stone size or location. However, there was a 3.6-fold difference in alpha-blocker use between the lowest and highest use ED sites. In the multivariable analysis, ED site was independently associated with utilization of alpha-blockers. CONCLUSIONS: Alpha-blockers were prescribed in more than two-thirds of patients with a distal ureteral stone on imaging, a much higher prevalence than previously reported. There was substantial variability in alpha-blocker use based on ED site.

Coronary Artery Calcium Score and Association with Recurrent Nephrolithiasis: The Multi-Ethnic Study of Atherosclerosis.

PURPOSE: Subclinical coronary artery calcification is an established predictor of cardiovascular events. While a history of kidney stones has been linked to subclinical carotid atherosclerosis, to our knowledge no study has examined its relationship with coronary artery calcification. We studied the association between kidney stone history and prevalent coronary artery calcification in MESA (Multi-Ethnic Study of Atherosclerosis). MATERIALS AND METHODS: MESA is a multisite cohort study of participants 45 to 84 years old without known cardiovascular disease at baseline from 2000 to 2002. Computerized tomography was done in 3,282 participants at followup in 2010 to 2012 to determine coronary artery calcification and kidney stone history was assessed by self-report. Coronary artery calcification scores were categorized as none-0, mild-1 to 99, moderate-100 to 399 or severe-400 or greater. Cross-sectional analysis was performed adjusting for demographic and dietary factors related to kidney stones. RESULTS: The prevalence of kidney stone disease history was approximately 9%, mean ± SD participant age was 69.5 ± 9.3 years, 39% of participants were Caucasian, 47% were men and 69% had detectable coronary artery calcification (score greater than 0). No difference in the score was seen between single stone formers and nonstone formers. Recurrent kidney stone formation was associated with moderate or severe calcification on multivariable logistic regression vs none or mild calcification (OR 1.80, 95% CI 1.22-2.67). When coronary artery calcification scores were separated into none, mild, moderate and severe calcification, recurrent stone formation was associated with a higher score category on multivariable ordinal logistic regression (OR 1.44 per category, 95% CI 1.04-2.01). CONCLUSIONS: Recurrent kidney stone formation is associated with subclinical coronary atherosclerosis. This association appeared stronger with coronary artery calcification severity than with coronary artery calcification presence.