Abstracts from the New England Section of the AUA 2020: A Virtual Experience

NE AUA 2020 Abstracts Outcomes of Active Surveillance for Asymptomatic Renal Stones Shuo-chieh Wu, MD 1 , Amanda R. Swanton, MD 1 , Kevin J. Krughoff, MD 1 , Benjamin M. Dropkin, MD 2 , Vernon M. Pais, Jr., MD 1 1 Dartmouth-Hitchcock Medical Center, Lebanon, NH; 2 Vanderbilt University Medical Center, Nashville, TN Introduction: Asignificant proportion of patients with asymptomatic nephrolithiasis pur- sue active surveillance with periodic imaging reassessment. While on surveillance, some patients will become symptomatic, but it is difficult to predict which patients will develop symptoms and over what time course symptoms will arise. We report the extended follow upoutcomesofacohortofpatientswithplannedsurveillanceofasymptomaticrenalstones. Material & Methods: Medical records of patients with asymptomatic non-obstructing renal calculi who had declined initial surgical intervention and opted for active surveil- lance between 2008-2018 were retrospectively reviewed. Baseline demographics, stone size, number and location were collected. Cox proportional-hazards model was used to identify predictors of renal colic and to analyze clinical outcomes based on initial stone burden. Kaplan-Meier curve and log-rank test were used to examine event-free survival. Results: A total of 110 patients (Male = 60, Female = 50) with 160 stones were followed for 71 ± 35 months (median = 85). Stone size of the cohort was 7.0 ± 4.2 mm (median = 6). Symptoms developed in 41.8% of patients, comprising 35.6% of stones in the entire cohort by 31 ± 24 months (median = 26). BMI ≥ 30 was associated with higher likelihood of symptom development (HR 1.91, CI 1.02-3.57, Table 1) and lower 5-year symptom free survival (50% vs. 71%, Figure 1). Age, gender, stone size, location, prior history of stones, and multiple renal stones were not associated with likelihood of symptom development. Clinical outcomes of the 160 stones are as follows: 12.5% triggered ER visit, 16.9% devel- oped hydronephrosis, 1.9%developed silent hydronephrosis, 9.4%passed spontaneously, 20.6% underwent surgery for symptoms, and 18.8% underwent elective surgery without symptoms (Table 2). On univariate Cox analysis of the association between stone character- istics and clinical outcomes, non-lower pole stones had higher likelihood for spontaneous passage compared to lower pole stones (HR 4.63, CI 1.15-20.35). Stone size greater than or equal to 10 mm was associated with more surgical intervention (HR 2.11, CI 1.21-3.55) and lower 5-year surgery free survival (40% vs. 66%, Figure 2). Conclusions: Over the course of 7-year median follow up for asymptomatic renal stones, most patients remain asymptomatic; a minority will spontaneously pass or require surgical intervention for symptoms. Those with higher BMI are more likely to develop symptoms, andstones≥10mmareassociatedwithan increasedoddsofultimatelyundergoingsurgical intervention.Activesurveillance isaviableoptionforasymptomaticrenalstones,and these data may aid in patient counseling. Readmission After Ureteroscopy for Patients Stented Due to Febrile UTI with Obstructing Stone Alexander J. Bandin, MD , Benjamin Press, MD, Jeremy E. Green, BA,AdamE. Ludvigson, MD, Thomas V. Martin, MD, Piruz Motamedinia, MD Yale New Haven Hospital, New Haven, CT Introduction: Patients presenting with an obstructing ureteral stone and signs of infection represent a surgical emergency, requiring urgent decompression. Patients who have a ureteral stent placed in this setting often undergo ureteroscopy (URS) for definitive stone management following recovery. For these patients we postulated an increased risk for postoperative infectious complications and higher rates of readmission than those published in the literature for all-comers undergoing URS (2-7%). Materials & Methods : A retrospective chart review was conducted at two hospitals associatedwith an academic medical center.After IRB approval, electronic medical records were reviewed from February 2012-June 2019.All patients who had a documented fever > 100.4º F and underwent a ureteral stent (CPT 52332) for obstructing stone were reviewed. Exclusion criteria included age < 18 years, lack of subsequent URS, time to URS > 6 months from stent placement, pregnancy, and non-stone indication for stent (UPJ obstruction, malignant obstruction, etc). Variables collected included Charlson Comorbidity Index (CCI), medical comorbidities, laboratory values, vital signs, and illness severity during initial presentation (QSOFA, ICU admission rates), as well as the use of access sheath, laser, and postoperative antibiotics at the time of definitive URS. Results : 135 patients were included in the study, of whom 18 patients (13.3%) required unplanned admission within 30 days after URS. 13 of those patients (9.6%) were admitted for symptomatic UTI. Of these 13 patients, 23% became septic in the PACU, 23% required ICU admission, and 15% required postoperative vasopressors. Average time to readmission was 5.4 days for patients who were discharged home after URS. Average length of readmission was 3.7 days. A documented history of UTIs aside from the event prompting initial stent placement was a significant predictor of readmission following URS (p = 0.009). Female gender (p = 0.055), systolic hypotension <100 mmHg during initial presentation (p = 0.085), and a return visit for symptomatic UTI (p = 0.085) did not achieve significance.Age, CCI, diabetes, stone size, initial illness severity (ICU admission, pressor requirement, QSOFA score, bacteremia), stent dwell time, postoperative antibiotics, and stone composition did not impact readmission rates. Conclusions : Patients who exhibit signs of infection coincident with an obstructing ureteral stone are at high risk of unplanned admission following URS for stone clearance. This risk is significantly increased for patients who have a prior history of recurrent UTIs. Patients who are readmitted have a high rate of severe illness requiring ICU-level care. Consideration should be given to closer post-operative follow-up or overnight monitoring for these patients, and they should be counseled appropriately about their elevated risk. 15 14 7 Scientific Session II: Stones I