UK Tertiary Centre Research Articles

Understanding the patient profile and health-related quality of life in patients presenting for hand surgery.

The aim of this descriptive epidemiological study of patients, referred to and selected for surgery at a UK tertiary hand centre, was to investigate patterns of common hand disorders and their impact on those individuals. A prospective collection of patient-reported outcome scores was carried out in patients before operation using the Patient Outcomes of Surgery Hand/Arm and the Euro-Qol 5 dimension three-level measures. Patient participation was voluntary and data collected over a 4-year period are discussed. Patient-reported outcome scores were calculated using appropriate algorithms. The results show correlation between the number of comorbidities and both symptoms and activity domains of the Patient Outcomes of Surgery Hand/Arm; higher symptom scores were seen in women. There was no increase in scores for older patients or those from more deprived areas. Population-based research using recognized patient-reported outcome measurement tools could aid future health service planning. Level of evidence: IV.

P2837Day-case complex left atrial ablation is safe and cost-effective: experience from a UK tertiary centre

Abstract Background Day-case standard catheter ablation is becoming routine. However, patients having complex left atrial ablation for atrial fibrillation (AF) or left atrial tachycardia (LAT) often stay overnight. We have been performing day-case complex left atrial ablation since 2015. Purpose To evaluate the safety, efficacy and cost-effectiveness of day-case complex left atrial ablation compared with those who stayed overnight. Methods A retrospective analysis of all consecutive complex left atrial ablations performed in a UK tertiary cardiac centre between 2010–2018. Data were collected on baseline parameters, procedure details including mapping technique, ablation strategy, immediate efficacy, and acute complications. Results A total of 830 complex left atrial catheter ablations were performed; mean age±SD=60±12 years, 63% male. The majority were AF ablation (n=804, 96.9%), with the rest being LAT/left-atrial flutter. Of the AF cases, 545 were paroxysmal (≤7 days), 212 persistent (>7 days) and 47 long-standing (>1yr); 98% of cases were elective. Pulmonary vein isolation was performed in all; additional LA lines were done in 163, CTI ablation in 129 and CFAEs in 33. 3D-mapping (Carto/Precision)=44.7% (with contact sensing=38.0%), PVAC=18.7%, PVI cryo-balloon=36.6%. Of the cohort 331 (39.9%) were done as day-case. Acute success= 94.9%, acute complications=4.58% (femoral site complications, n=12; pericardial effusion, n=19 (9 needing drain); stroke/cerebral embolus, n=3; phrenic nerve palsy, n=5; first degree heart block, n=1). Comparison of day-case vs non day-case revealed no significant difference in number of complications (Table 1). An overnight stay at out hospital costs £350. During the period of study our institution saved £115.850 (∼140,000 euros). Day-case vs non day-case ablation Parameters Day-case (n=331) Non day-case (n=499) p-value Mean age ± SD (years) 61.2±11.6 59.1±11.9 0.009 Males (n, %) 205 (61.9%) 321 (64.3%) 0.484 Normal heart (n, %) 243 (73.4%) 383 (76.8%) 0.276 Paroxysmal AF (n, %) 218 (65.9%) 327 (65.5%) 0.928 Fluoroscopy time (mins) 23.8±13.9 27.0±14.5 0.001 Procedure time (mins) 150±89.6 163±68.2 0.025 % with 3D-mapping 30.8% 56.9% <0.001 Acute complications (n, %) 12 (3.63%) 26 (5.21%) 0.285 Conclusions Day-case complex left atrial cardiac ablation is safe and effective. It is associated with good clinical outcomes and leads to significant cost savings as an overnight stay is not needed.

1611P - Specialist palliative care (SPC) in haematological malignancy: Establishing practices in a UK tertiary cancer centre (TCC)

BackgroundInternational consensus supports early integration of SPC in oncological disease. Haematological malignancies differ in nature from solid site tumours. Remitting and relapsing trajectories, late salvage treatments, and divergent outcomes make for difficult prognostication and traditional markers of ‘good’ end of life care may not translate well to this group. However, disease is often incurable and physical and psychological symptom burden high, making SPC input essential. The authors propose an integrated care model to achieve this, utilising predefined triggers to identify unmet need and to guide SPC involvement from time of diagnosis. Such a service, “Triggers”, has been successfully developed for other cancer groups at the TCC. Through improved understanding of current practices we plan to tailor this service to meet the unique needs of the haematology patient group. MethodsA retrospective audit of electronic records was completed for patients dying of haematology malignancy in the 12 months to 31/3/18. Data relating to SPC referral, DNAR documentation, active interventions, place of death and diagnosis sub-type was collected. ResultsOf 108 patients identified, 67 died in hospitals, including 43 at the TCC. Of 26 deaths within 30 days of discharge from the TCC, 100% of those with a previous SPC referral (16) died in the community while 80% of those without (10) died in a local hospital.Table1611PTableTotals / RangeMedianDeaths in year ending 31/3/19108Documented referrals to SPC72/108Time from Diagnosis to death0 – 23 years3 yearsTime from SPC referral to death0 – 10 years6 daysFor Tertiary Centre in-patient deaths only:Number of TCC in-patient deaths43Chemotherapy in last 30 days25/43Blood transfusion in last 30 days38/432 days pre deathPlatelets in last 30 days34/433 days pre deathTPN in last 30 days11/434 days pre deathTime from DNAR record to death0 – 30 days3 days pre death ConclusionsHaematological intervention remains frequent up until death but SPC involvement is relatively delayed. Later SPC input is expected to limit effective relationship building and advance care planning and the data shows differences in place of death for those with and without SPC referral. Results suggest an opportunity to support patient-centred care through the development of an integrated service with early SPC accessibility and a consultative survey is underway to ascertain how this might best be achieved. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

630P - mCRC gene profiling using the Idylla platform

BackgroundKRAS, NRAS and BRAF mutation testing for metastatic colorectal cancer (mCRC) is essential to guide treatment and prognostication. Multiple gene profiling assays are available, each with differing tumour sample size/quality requirements and turnaround time (TAT). Many UK hospitals send samples to off-site labs for profiling. A rapid TAT is desirable to plan appropriate chemotherapy +/- biologics from cycle one, as well as providing certainty and satisfaction for patients and clinicians. MethodsThis study was conducted at 2 UK tertiary cancer centres (University College London Hospital and Mount Vernon Hospital), comparing a pathway where gene profiling of mCRC was performed off-site using an NGS platform versus on-site testing using the Idylla platform (Biocartis, Mechelen, Belgium). Up to 50 patients were included in each group with 8 of the Idylla tests being used for samples that had failed with the NGS platform. ResultsMutational profiling results for the whole cohort that were successfully tested (n=84) showed 26% (22/84) were wildtype for KRAS/NRAS/BRAF, 62% (52/84) KRAS mutated, 2% (2/84) NRAS mutated, 10% (8/84) BRAF mutated. The median TAT in days (median, interquartile range (IQR)) of the on-site Idylla pathway was shorter than the off-site NGS pathway (4, 1 - 6 vs. 15, 13-17; p=<0.0001). In the off-site group median time from request to receipt of sample was 3 days (IQR 2 - 5) and median time from receipt to result was 10 days (IQR 9 - 13). Test failure rate was significantly higher with the NGS test (30%, 15/50) compared to the Idylla test (2%, 1/50) (p=0.0001). 8 samples that had failed testing with the NGS platform, due to insufficient/low quality of sample, were all successfully tested with the Idylla platform. ConclusionsFor gene profiling of mCRC, on-site testing with the Idylla platform significantly shortened the TAT, lowered failure rate and was able to test more sub-optimal samples compared to off-site NGS testing. Updated results integrating these data with tumour location, MMR status and treatment outcomes will be presented at ESMO 2019. Legal entity responsible for the studyThe authors. FundingBiocartis provided the Idylla test kits for this study without charge. DisclosureN. Bhuva: Honoraria (self), supported in attending international meetings: Amgen; Honoraria (self), supported in attending international meetings: Bristol-Myers Squibb. K. Shiu: Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Roche; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Merck Group; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Servier; Honoraria (self), Advisory / Consultancy, supported in attending lectures and conferences: Guardant Health. All other authors have declared no conflicts of interest.

1704P - Neo-adjuvant (NA) Imatinib for gastrointestinal stromal tumours (GISTs): What is the optimal length of treatment?

BackgroundGISTs are rare tumours with an incidence of around 1/100000/year. The principle treatment in localised disease remains resection. If an R0 resection is not expected, Imatinib can be used in the NA setting to shrink tumours and improve chances of a complete resection. Current guidelines suggest Imatinib should be used for 6-12 months in the NA setting. MethodsData were collected for patients treated for GISTs with Imatinib in either the NA or palliative (PA) setting in two UK tertiary centres to assess response in the primary tumour volume (PTV). This study aimed to find the time to maximum reduction of PTV in NA and PA settings. Results29 patients were treated with Imatinib over a 3 year period; 13 in the PA setting and 16 in the NA setting. In the NA setting, 10 patients proceeded to surgery, 2 patients declined surgery and 4 patients remained inoperable. All patients deemed operable at baseline underwent surgery after NA Imatinib. The median time to surgery was 7.2mths (Range (R) 1.6 – 28.9mths). Overall, 10 patients died (none in the NA setting), 5 on treatment and 5 post-treatment. At baseline, the median PTV was 199.3cm3 (R 4.0 – 10472.0cm3). The median time to best response was 7.6mths (R 1.4 – 46.2mths) for all patients, 4.7mths (R 1.4 – 21.6mths) in NA patients and 14.1mths (R 3.3 – 46.2mths) in PA patients. As the majority of NA patients did not have progressive disease (PD) prior to surgery, the maximum response may not have been reached and therefore the results in PA patients may better reflect the time to best response. 9 patients had PD, 2 in NA setting with 1 patient proceeding to surgery. The median time to PD for all patients was 19.6mths (R 1 – 51.4mts). The overall response rate to Imatinib was 85.2%. The median reduction in PTV was 65.3% (R -182.7 – 93.4%). In NA patients the median reduction in PTV was 62.7% (R -182.7 – 93.4%) and in PA patients the median reduction in PTV was 57.6% (R 20 – 82.4%). ConclusionsImatinib has high response rates in both the NA and PA settings. This study suggests the maximum reduction in PTV can be achieved after greater than 12mths of treatment. For patients responding to NA Imatinib who have ongoing concerns regarding resectability, a more prolonged course of treatment may further reduce PTV to facilitate an R0 resection. Legal entity responsible for the studySharath Gangadhara. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

P2243CTCA alone demonstrates superior diagnostic accuracy, prognostic utility and is less expensive than CTCA combined with subsequent multi-modality functional imaging in patients with ischaemic symptoms

Abstract Background The evaluation of suspected ischaemic symptoms incorporates multi-modality anatomical and functional imaging tests. The 2016 update to the UK's NICE guidelines recommends CT coronary angiogram (CTCA) first line in patients without known coronary artery disease. Additive multi-modality functional imaging may provide synergistic diagnostic and prognostic information. Purpose To investigate the diagnostic accuracy, prognostic utility and cost of CTCA combined with subsequent multi-modality functional testing versus (vs) CTCA alone. Methods 772 consecutive patients were referred to a single UK tertiary centre with symptoms suggestive of ischaemia. 657 individuals (“CTCA group”) underwent CTCA alone, and 115 individuals (“Combined group”) underwent CTCA and then either perfusion cardiac MRI (n=25), stress echocardiogram (n=16), or myocardial perfusion scintigraphy (n=74). Patients underwent invasive angiography (n=79) +/− revascularisation at the discretion of the referring clinician. All readers and operators were aware of previous imaging findings. Revascularised patients (n=52) were excluded from long term follow-up. The remaining patients were followed-up for a mean of 38.1±17.4 months and the incidence of major adverse cardiovascular events (MACE) recorded. Costs were derived from the NICE guidelines. Results Baseline characteristics were similar between groups. The Combined group underwent significantly more invasive angiograms than the CTCA group (29.6% vs 6.8%, p=0.0001) with no significant difference in the rate of revascularisation (73% vs 67%, p=0.72). Mean time from CTCA to angiogram was significantly longer in the Combined group (81.2 vs 38.1 days, p=0.0001). Both sensitivity and specificity were lower in the Combined group than in the CTCA group (sensitivity: 70% vs 93%, specificity: 75% vs 100%). The rate of long term MACE was significantly higher in the Combined group (8.7% vs 2.6%, p=0.0026). Multivariate analysis of CTCA and functional imaging findings found that CTCA-derived four vessel aggregate stenosis score (0–12) was the strongest predictor of MACE for the whole cohort (OR 4.4, p&lt;0.0001), and also for those with negative functional tests (OR 3.9, p&lt;0.0001). Per patient, a combined strategy was more expensive than CTCA alone (£1551 vs £368, p=0.0001). CTCA and functional data vs outcomes Conclusions Combining multi-modality functional testing with CTCA increased costs but did not improve diagnostic accuracy or long term outcomes. Further reductions in both MACE and unnecessary invasive angiography are desirable; CT-derived functional data such as FFRCT may be implicated.

OP12.10: Pregnancy loss following chorionic villus sampling or amniocentesis in twin pregnancies: two decades in a UK tertiary fetal medicine centre

OP12.10: Pregnancy loss following chorionic villus sampling or amniocentesis in twin pregnancies: two decades in a UK tertiary fetal medicine centre

\u2018Caveat emptor\u2019: the cautionary tale of endocarditis and the potential pitfalls of clinical coding data\u2014an electronic health records study

BackgroundDiagnostic codes from electronic health records are widely used to assess patterns of disease. Infective endocarditis is an uncommon but serious infection, with objective diagnostic criteria. Electronic health records have been used to explore the impact of changing guidance on antibiotic prophylaxis for dental procedures on incidence, but limited data on the accuracy of the diagnostic codes exists. Endocarditis was used as a clinically relevant case study to investigate the relationship between clinical cases and diagnostic codes, to understand discrepancies and to improve design of future studies.MethodsElectronic health record data from two UK tertiary care centres were linked with data from a prospectively collected clinical endocarditis service database (Leeds Teaching Hospital) or retrospective clinical audit and microbiology laboratory blood culture results (Oxford University Hospitals Trust). The relationship between diagnostic codes for endocarditis and confirmed clinical cases according to the objective Duke criteria was assessed, and impact on estimations of disease incidence and trends.ResultsIn Leeds 2006–2016, 738/1681(44%) admissions containing any endocarditis code represented a definite/possible case, whilst 263/1001(24%) definite/possible endocarditis cases had no endocarditis code assigned. In Oxford 2010–2016, 307/552(56%) reviewed endocarditis-coded admissions represented a clinical case. Diagnostic codes used by most endocarditis studies had good positive predictive value (PPV) but low sensitivity (e.g. I33-primary 82% and 43% respectively); one (I38-secondary) had PPV under 6%. Estimating endocarditis incidence using raw admission data overestimated incidence trends twofold. Removing records with non-specific codes, very short stays and readmissions improved predictive ability. Estimating incidence of streptococcal endocarditis using secondary codes also overestimated increases in incidence over time. Reasons for discrepancies included changes in coding behaviour over time, and coding guidance allowing assignment of a code mentioning ‘endocarditis’ where endocarditis was never mentioned in the clinical notes.ConclusionsCommonly used diagnostic codes in studies of endocarditis had good predictive ability. Other apparently plausible codes were poorly predictive. Use of diagnostic codes without examining sensitivity and predictive ability can give inaccurate estimations of incidence and trends. Similar considerations may apply to other diseases. Health record studies require validation of diagnostic codes and careful data curation to minimise risk of serious errors.

Long-term follow-up of normal and structural heart ventricular tachycardia catheter ablation: real-world experience from a UK tertiary centre

BackgroundVentricular tachycardia (VT) is associated with increased morbidity and mortality. There is growing evidence for the effectiveness of catheter ablation in improving outcomes in patients with recurrent VT. Consequently the...

Intussusception: A 14-year experience at a UK tertiary referral centre

AimsIntussusception is the most common cause of acute intestinal obstruction in infants. First line management in uncomplicated cases at our centre is fluoroscopy guided air enema reduction. This study reports a 14 year UK single centre experience highlighting management and outcomes of intussusception in children. MethodsAll cases of intussusception (ICD 10-code K56.1) at a single tertiary referral centre from 2004 to 2017 were analyzed. Data evaluated included patient demographics, clinical presentation, treatment modality(s), complications and outcome(s). ResultsTwo hundred ninety confirmed cases (69% male) of intussusception were identified during the study period. The median age at presentation was 9.5 months (range 4 days–15 years). One hundred eighty-six (64%) cases occurred in children who were transferred to Alder Hey from peripheral district hospitals. One hundred ninety-six cases (68%) proceeded directly to air enema reduction and successful reduction was achieved in 129 cases (66%). A single case (0.5%) of attempted air enema reduction was complicated by perforation. Early recurrence rate following air enema reduction was 9%. Operative management was indicated in 140 (48%) cases of which 66 required bowel resection (47%). There were no deaths. ConclusionsWe highlight one of the largest single centre UK studies defining practice outcomes for intussusception across the British Isles. Our centre has achieved a 66% success rate of non-operative reduction over 14 years in line with the British Society Pediatric Radiology (BSPR) recommendations and within 5% of the national median metric (71%). Moreover these outcomes were achieved with a very low complication rate (0.5%) from air enema reduction and no mortality in the series. Type of studyRetrospective study. Level of evidenceIII

Early Experience of Trans-arterial Chemo-Embolisation for Hepatocellular Carcinoma with a Novel Radiopaque Bead

AimsTo evaluate early outcomes of patients with hepatocellular carcinoma (HCC) treated with a novel radiopaque bead, the 75–150 μm DC Bead LUMI™ (Biocompatibles UK Ltd).Materials and MethodsThis was a retrospective review of the first 40 consecutive patients at a UK tertiary hepato-biliary centre, treated for HCC with TACE using radiopaque beads, between May 2017 and March 2019. Information regarding complications, mortality, lesion response and subsequent ablation procedures was collected from electronic records and case notes. Intra- and post-operative imaging was reviewed for visibility of the embolised territory.ResultsFifty-five TACE procedures were performed in 40 patients, with a median age of 70 years (range 28–88) and median lesion size of 3.8 cm (range 1.5–7.8). The median follow-up period was 30 weeks (range 6–101). Mean post-procedure hospital stay was 1.2 days. Complications of CIRSE Grade II or above occurred after 4/55 procedures (7.3%). Mortality at 30 days was zero. Objective response rates (mRECIST) at 1, 3 and 6 months were 32/35 (91.4%), 21/24 (87.5%) and 12/15 (80%), respectively. Complete response rates at 1, 3 and 6 months were 16/35 (45.7%), 12/24 (50%) and 9/15 (60%). The embolised territory was visible on intra-operative and follow-up CT imaging in all patients. The radiopaque beads were used as a fiducial marker to guide ablation in 5/40 patients (12.5%).ConclusionTACE with radiopaque beads shows promising tolerability and efficacy. The radiopaque beads ensure visualisation of the embolised lesion on intra- and post-operative imaging and, in selected cases, can act as a marker for CT-guided ablation.

Prognostic Value of Subcarinal Lymph Nodes in Minimally Invasive Esophagectomy for Cancer.

Surgical resection for esophageal cancer has remained the gold-standard therapy provided worldwide. Subcarinal lymph-nodes are classified as peri-esophageal nodes and their dissection may be performed during a 2- or 3-stage esophagectomy. The necessity and prognostic value of subcarinal lymphadenectomy is still debatable. The purpose of this study was to investigate the rate of invaded subcarinal lymph-nodes out of the total lymph-nodes resected. Detection of invaded nodes was correlated with clinical staging and tumor differentiation. This is a retrospective analysis of consecutive esophagectomies for cancer, performed in a UK tertiary center. The study was conducted over a 3-year period. The rate of subcarinal lymph-node invasion was extremely low according to the results of our analysis. Lymphadenectomy is not devoid of clinical impact on patients and therefore, the decision should actually be the outcome of a dynamic balance between complications and survival benefit.

Incisional hernia and enterocutaneous fistula in patients with chronic intestinal failure: prevalence and risk factors in a cohort of patients referred to a tertiary centre.

This study aims to determine the prevalence of incisional hernia (IH) and enterocutaneous fistula (ECF) in patients with intestinal failure (IF) referred to a tertiary centre and to identify factors associated with their development. A retrospective case note review was undertaken of a prospectively maintained database of all patients on home parenteral nutrition between 2011 and 2016 at a UK tertiary referral centre for IF. Risk factors were identified using binary logistic regression. The database search identified 447 patients, of whom 349 (78.1%) had surgery prior to developing IF. Eighty-one (23.2%) patients had an IH and 123 (35.2%) had an ECF at the time of referral. Of these, 51 (14.6%) had both IH and ECF. IH was associated with a high body mass index (P=0.05), a history of a major surgical complication resulting in IF (P=0.01), previous emergency surgery (P=0.04), increasing number of operations (P=0.02) and surgical site infection (SSI; P=0.01). ECF was associated with complications relating to earlier surgery. (P≤.001), previous treatment with an open abdomen (P=0.03), SSI (P=0.001), intra-abdominal collection (P≤0.001) and anastomotic leak (P=0.02). In this series, patients with IF had a prevalence of IH which was more than double that expected following elective laparotomy (about 10%) and one in three had an ECF. Risk factors for IH and ECF are discussed.

Total body skin examination increases squamous cell carcinoma detection: a retrospective cohort study.

Squamous cell carcinomas (SCCs) have the potential for local tissue destruction and metastasis. The risk of complications increases if the lesion is not diagnosed and excised in a timely manner. Total body skin examination (TBSE) has been reported to increase melanoma detection; the objective of this study was to determine if it also increases SCC detection. Analysis of 469 SCCs diagnosed at a UK tertiary centre showed that 6.8% of these were detected incidentally and not from the index lesion that prompted referral. These incidentally detected SCCs tended to represent early disease, and therefore carried lower risk of complications. Our findings suggest that full skin checks may increase the number of SCCs detected, and at an earlier stage of disease. Therefore, we encourage the use of TBSE in all dermatology outpatient appointments, and make suggestions as to how to incorporate it into the limited time available in dermatology clinics.

Motion-corrected free-breathing LGE delivers high quality imaging and reduces scan time by half: an independent validation study

Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) sequences have evolved. Free-breathing motion-corrected (MOCO) LGE has potential advantages over breath-held (bh) LGE including minimal user input for the short axis (SAX) stack without breath-holds. It has previously been shown that MOCO-LGE delivers high image quality compared to bh-LGE. We sought to conduct an independent validation study to investigate real-world performance of bh-LGE versus MOCO-LGE in a high-throughput CMR center immediately after the introduction of the MOCO-LGE sequence and with elementary staff induction in its use. Four-hundred consecutive patients, referred for CMR and graded by clinical complexity, underwent CMR on either of two scanners (1.5 T, both Siemens) in a UK tertiary cardiac center. Scar imaging was by bh-LGE or MOCO-LGE (both with phase sensitive inversion recovery). Image quality, scan time, reader confidence and report reproducibility were compared between those scanned by bh-LGE versus MOCO-LGE. Readers had > 3 years CMR experience. Categorical variables were compared by χ2 or Fisher’s exact tests and continuous variables by unpaired Student’s t-test. Inter-rater agreement of LGE reports was by Cohen’s kappa. Image quality (low score = better) was better for MOCO-LGE (median, interquartile range [Q1–Q3]: 0 [0–0] vs. 2 [0–3], P < 0.0001). This persisted when just clinically complex patients were assessed (0 [0–1] vs. 2 [1–4] P < 0.0001). Readers were more confident in their MOCO-LGE rulings (P < 0.001) and reports more reproducible [bh-LGE vs. MOCO-LGE: kappa 0.76, confidence interval (CI) 0.7–0.9 vs. 0.82, CI 0.7–0.9]. MOCO-LGE significantly shortened LGE acquisition times compared to bh-LGE (for left ventricle SAX stack: 03:22 ± 01:14 vs 06:09 ± 01:47 min respectively, P < 0.0001). In a busy clinical service, immediately after its introduction and with elementary staff training, MOCO-LGE is demonstrably faster to bh-LGE, providing better images that are easier to interpret, even in the sickest of patients.

Outcomes of ureteroscopy (URS) for stone disease in the paediatric population: results of over 100 URS procedures from a UK tertiary centre

PurposeTo report the outcomes of paediatric ureteroscopy (URS) for stone disease from a specialist endourology centre in the UK. Ureteroscopy for management of stone disease has increased worldwide and is now being done more commonly in the paediatric age group.MethodsData were analysed retrospectively from a database maintained between April 2010 and May 2018. Consecutive patients ≤ 16 years of age undergoing semi-rigid or flexible URS for stone disease were included. Stone size and stone-free rate (SFR) were routinely assessed using an ultrasound (USS) and/or plain KUB XR. Complications were graded according to the Clavien–Dindo classification and recorded within 30 days post-procedure and readmissions within 90 days after the procedure were also captured.ResultsOver the 8-year period between April 2010 and April 2018, 81 patients with a mean age of 8.8 years (range 18 months–16 years) and a male to female ratio 1:1.1 underwent 102 procedures (1.28 procedure/patient to be stone free). Of the 81 patients, 29 (35.8%) had comorbidities, with 26 (32%) having multiple comorbidities. The mean (± SEM) single and overall stone size was 9.2 mm (± 0.48, range 3–30 mm) and 11.5 mm (± 0.74, range 4–46 mm) respectively, with 22 (27.1%) having multiple stones. Thirty-five (34.7%) had stent in situ pre-operatively. The stone location was in the ureter (26.6%), lower pole (35.4%), and renal pelvis (16.5%), with 22/81(27%) having multiple stones and 21/102 (20.5%) where a ureteral access sheath (UAS) was used.With a mean hospital stay of 1.2 days, the initial and final SFR was 73% and 99%, respectively, and 61/102 (60%) had ureteric stent placed at the end of the procedure. While there were no intra-operative complications, the readmission rate was less than 1% and there were only three early complications recorded. This included a case each of prolonged admission for pain control (grade I), urinary retention (grade II) and post-operative sepsis requiring a brief ITU admission (grade IV).ConclusionOur study demonstrates that in appropriate setting a high stone-free rate can be achieved with minimal morbidity for paediatric patients. There is potentially a need to factor the increasing role of URS in future paediatric urolithiasis guidelines.

Identifying Low-Risk Beta-Lactam Allergy Patients in a UK Tertiary Centre

There are marked geographical as well as temporal differences in patient sensitization profiles to β-lactams (BL). To determine the utility of skin test reagents and identify a cohort of patients where skin testing can be safely omitted in a cohort of patients referred to a UK tertiary referral center. A retrospective study of the clinical characteristics of 1092 patients referred for BL allergy testing was analyzed using multivariate regression analysis. The effectiveness of skin test reagents was also evaluated. Multivariate logistic regression identified that a history of anaphylaxis (odds ratio [OR] 10.98, P= .001) and the patients' recall of the index drug (apart from ampicillin and meropenem, OR 3.51-12.43, P < .05) were independent predictors of type I BL allergic status and a time of less than 1 year elapsed since index reaction significantly increasing the odds of a patient with a history of anaphylaxis, having a type I BL allergy (OR 38.66, P= .003). An absence of anaphylactic severity, unknown name of the index drug and a reaction occurring more than 1 year before testing, has a negative predictive value (NPV) of 98.4%, which was similar to the NPV of skin testing of 98.9% for type I BL allergy. The NPV of skin testing with benzylpenicillin+ amoxicillin ± index BL was similar with (98.9%) or without (98.1%) the use of benzylpenicillin polylysine and minor determinant for type I BL allergy. We identified a "low risk" cohort of patients where the history is of similar reliability to skin testing in predicting nonallergic status for BL allergy.

442 - Outcomes of ureteroscopy (URS) for stone disease in the paediatric population: Results of over 100 URS procedures from a UK tertiary centre

To report the outcomes of paediatric ureteroscopy (URS) for stone disease from a specialist endourology centre in the UK. Ureteroscopy for management of stone disease has increased worldwide and is now being done more commonly in the paediatric age group. Data were analysed retrospectively from a database maintained between April 2010 and May 2018. Consecutive patients ≤ 16 years of age undergoing semi-rigid or flexible URS for stone disease were included. Stone size and stone-free rate (SFR) were routinely assessed using an ultrasound (USS) and/or plain KUB XR. Complications were graded according to the Clavien–Dindo classification and recorded within 30 days post-procedure and readmissions within 90 days after the procedure were also captured. Over the 8-year period between April 2010 and April 2018, 81 patients with a mean age of 8.8 years (range 18 months–16 years) and a male to female ratio 1:1.1 underwent 102 procedures (1.28 procedure/patient to be stone free). Of the 81 patients, 29 (35.8%) had comorbidities, with 26 (32%) having multiple comorbidities. The mean (± SEM) single and overall stone size was 9.2 mm (± 0.48, range 3–30 mm) and 11.5 mm (± 0.74, range 4–46 mm) respectively, with 22 (27.1%) having multiple stones. Thirty-five (34.7%) had stent in situ pre-operatively. The stone location was in the ureter (26.6%), lower pole (35.4%), and renal pelvis (16.5%), with 22/81(27%) having multiple stones and 21/102 (20.5%) where a ureteral access sheath (UAS) was used. With a mean hospital stay of 1.2 days, the initial and final SFR was 73% and 99%, respectively, and 61/102 (60%) had ureteric stent placed at the end of the procedure. While there were no intra-operative complications, the readmission rate was less than 1% and there were only three early complications recorded. This included a case each of prolonged admission for pain control (grade I), urinary retention (grade II) and post-operative sepsis requiring a brief ITU admission (grade IV). Our study demonstrates that in appropriate setting a high stone-free rate can be achieved with minimal morbidity for paediatric patients. There is potentially a need to factor the increasing role of URS in future paediatric urolithiasis guidelines.

120 - Tumour seeding the tract of percutaneous renal tumour biopsy: A report of seven cases from a UK tertiary referral centre

120 - Tumour seeding the tract of percutaneous renal tumour biopsy: A report of seven cases from a UK tertiary referral centre

Differing presenting features of idiopathic intracranial hypertension in the UK and US.

Demographic factors potentially influencing the presentation and severity of idiopathic intracranial hypertension (IIH) in the US vs. UK populations include obesity and ethnicity. We aimed to compare the presenting features of IIH between populations in the UK and US tertiary referral centres, to assess what population differences exist and whether these cause different presentations and impact on visual function. Clinical data were collected on 243 consecutive UK IIH patients and 469 consecutive US IIH patients seen after 2012 in two tertiary centres. Visual function was defined as severe visual loss when Humphrey visual field mean deviation was <-15 dB, when Goldmann visual fields showed constriction or when visual acuity was <20/200. US patients were more commonly of self-reported black race (58.9% vs. 7.1%) than UK patients, but had a similar mean body mass index (38.3 ± 0.63kg/m2 UK vs. 37.7 ± 0.42kg/m2 US; p = 0.626). The UK cohort had lower presenting Frisén grade (median 1 vs. 2; p < 0.001) and severe visual loss less frequently (15.4% vs. 5%; p = 0.014), but there was no difference in mean cerebrospinal fluid-opening pressure (CSF-OP) (35.8 ± 0.88cmH2O UK vs. 36.3 ± 0.52cmH2O US; p = 0.582). African Americans had poorer visual outcomes compared with US whites (19.4% vs. 10% severe visual loss; p = 0.011). Visual function was weakly associated with CSF-OP (R2 = 0.059; p = 0.001), which was similar between UK and US patients. The UK and the US cohorts had a similar average presenting BMI. However, the worse presenting visual function in the US IIH cohort was partially attributable to differences in the black populations in the two countries.