Learning the Structure of Auto-Encoding Recommenders

Autoencoder recommenders have recently shown state-of-the-art performance in the recommendation task due to their ability to model non-linear item relationships effectively. However, existing autoencoder recommenders use fully-connected neural network layers and do not employ structure learning. This can lead to inefficient training, especially when the data is sparse as commonly found in collaborative filtering. The aforementioned results in lower generalization ability and reduced performance. In this paper, we introduce structure learning for autoencoder recommenders by taking advantage of the inherent item groups present in the collaborative filtering domain. Due to the nature of items in general, we know that certain items are more related to each other than to other items. Based on this, we propose a method that first learns groups of related items and then uses this information to determine the connectivity structure of an auto-encoding neural network. This results in a network that is sparsely connected. This sparse structure can be viewed as a prior that guides the network training. Empirically we demonstrate that the proposed structure learning enables the autoencoder to converge to a local optimum with a much smaller spectral norm and generalization error bound than the fully-connected network. The resultant sparse network considerably outperforms the state-of-the-art methods like \textsc{Mult-vae/Mult-dae} on multiple benchmarked datasets even when the same number of parameters and flops are used. It also has a better cold-start performance.Comment: Proceedings of The Web Conference 202

Validation of the Baveno Vi Criteria to Identify Low Risk Cirrhotic Patients not Requiring Endoscopic Surveillance for Varices

BACKGROUND: The Baveno VI guidelines propose that cirrhotic patients with a liver stiffness measurement (LSM) 150000/μL can avoid screening endoscopy as their combination is highly specific for excluding clinically significant varices. The aim of the study was to validate these criteria. METHODS: Transient elastography data was collected from two institutions from 2006-2015. Inclusion criteria were a LSM ⩾10kPa and an upper gastrointestinal endoscopy within 12 months, with a diagnosis of compensated chronic liver disease. Exclusion criteria were porto-mesenteric-splenic vein thrombosis and non-cirrhotic portal hypertension. Varices were graded as low risk (grade 150) are at low risk of having varices and do not need a screening endoscopy. Varices are a complication of cirrhosis, confer a risk of serious bleeding, and can be diagnosed and treated by endoscopy. Our study reviewed the clinical records of patients who have had liver stiffness scans and endoscopy over a 9 year period at two hospitals. The results show that only about 2% of patients who meet the Baveno VI criteria will be miss classified as not having varices

Modular component exchange and outcome of DAIR for hip and knee periprosthetic joint infection A SYSTEMATIC REVIEW AND META-REGRESSION ANALYSIS

AimsThe aim of this meta-analysis is to assess the association between exchange of modular parts in debridement, antibiotics, and implant retention (DAIR) procedure and outcomes for hip and knee periprosthetic joint infection (PJI).MethodsWe conducted a systematic search on PubMed, Embase, Web of Science, and Cochrane library from inception until May 2021. Random effects meta-analyses and meta-regression was used to estimate, on a study level, the success rate of DAIR related to component exchange. Risk of bias was appraised using the (AQUILA) checklist.ResultsWe included 65 studies comprising 6,630 patients. The pooled overall success after DAIR for PJI was 67% (95% confidence interval (CI) 63% to 70%). This was 70% (95% CI 65% to 75%) for DAIR for hip PJI and 63% (95% CI 58% to 69%) for knee PJI. In studies before 2004 (n = 27), our meta-regression analysis showed a 3.5% increase in success rates for each 10% increase in component exchange in DAIR for hip PJI and a 3.1% increase for each 10% increase in component exchange for knee PJI. When restricted to studies after 2004 (n = 37), this association changed: for DAIR for hip PJI a decrease in successful outcome by 0.5% for each 10% increase in component exchange and for DAIR for knee PJI this was a 0.01% increase in successful outcome for each 10% increase in component exchange.ConclusionThis systematic review and meta-regression found no benefit of modular component exchange on reduction of PJI failure. This limited effect should be weighed against the risks for the patient and cost on a case-by-case basis. The association between exchange of modular components and outcome changed before and after 2004. This suggests the effect seen after 2004 may reflect a more rigorous, evidence-based, approach to the infected implant compared to the years before.Immunogenetics and cellular immunology of bacterial infectious disease

Complications of the spine in ankylosing spondylitis with a focus on deformity correction

NKYLOSING spondylitis is a systemic inflammatory disease of unknown origin. Affected patients are predominantly but not exclusively male. Chronic inflammatory back pain is the most common presenting symptom and typically develops between the ages of 20 and 40 years. 65 Patients with AS can also have extra-articular manifestations such as ocular, cardiac, pulmonary, gastrointestinal, and renal involvement. A patient's susceptibility to the disease is largely genetically determined. 60 Because there is no single suitable laboratory test, clinicians must know as many of the characteristic signs and symptoms as possible to make a diagnosis. Even though AS is a systemic disease, the presenting symptoms, treatment, and morbidity are largely dependent on how the disease affects the spine. Thus, we believe that a review on spinal disease in AS will be of great value. In this review, we first describe the latest published algorithm to diagnose early disease and the classic inflammatory lesions. We then explore the diseased spine's susceptibility to noninflammatory lesions such as microfractures and deformity. We also describe other sequelae of AS, such as early osteoporosis and CES. Both the medical and surgical approaches to treatment are summarized. There is a special focus on osteotomy techniques. By the conclusion of the article, the clinician should have a better understanding of the diagnostic and treatment possibilities in AS spinal disease. Diagnosis of Inflammatory Back Pain and AS Because AS can markedly respond to the newer biological agents (discussed later), effective treatment of the disease requires early diagnosis. However, the high prevalence of back pain in the general population and the lack of radiographically demonstrated characteristic lesions in early AS often delay recognition of the disease. To make an early diagnosis, it is important to distinguish inflammatory from mechanical back pain on presentation. Factors consistent with inflammatory back pain include morning stiffness lasting longer than 30 minutes, onset of chronic back pain at an early age (before 35 years of age), improvement in pain with physical activity rather than with rest, awakening with back pain during the 2nd half of the night, alternating buttock pain, and a prolonged period of back pain. 48 One factor by itself does not have sufficient sensitivity or specificity to determine if the back pain is inflammatory. Note, however, that in a study of European patients with AS in which only 4 factors were considered, if 2 symptoms Abbreviations used in this paper: AS = ankylosing spondylitis; CES = cauda equina syndrome; DEXA = dual energy x-ray absorptiometry; HLA = human leukocyte antigen; MR = magnetic resonance; NSAID = nonsteroidal antiinflammatory drug; PSO = pedicle subtraction osteotomy; SPO = Smith-Peterson osteotomy; TNF = tumor necrosis factor

Survival of patients treated with intra-aortic balloon counterpulsation at a tertiary care center in Pakistan – patient characteristics and predictors of in-hospital mortality

BACKGROUND: Intra-aortic balloon counterpulsation (IABC) has an established role in the treatment of patients presenting with critical cardiac illnesses, including cardiogenic shock, refractory ischemia and for prophylaxis and treatment of complications of percutaneous coronary interventions (PCI). Patients requiring IABC represent a high-risk subset with an expected high mortality. There are virtually no data on usage patterns as well as outcomes of patients in the Indo-Pakistan subcontinent who require IABC. This is the first report on a sizeable experience with IABC from Pakistan. METHODS: Hospital charts of 95 patients (mean age 58.8 (± 10.4) years; 78.9% male) undergoing IABC between 2000–2002 were reviewed. Logistic regression was used to determine univariate and multivariate predictors of in-hospital mortality. RESULTS: The most frequent indications for IABC were cardiogenic shock (48.4%) and refractory ischemia (24.2%). Revascularization (surgical or PCI) was performed in 74 patients (77.9%). The overall in-hospital mortality rate was 34.7%. Univariate predictors of in-hospital mortality included (odds ratio [95% CI]) age (OR 1.06 [1.01–1.11] for every year increase in age); diabetes (OR 3.68 [1.51–8.92]) and cardiogenic shock at presentation (OR 4.85 [1.92–12.2]). Furthermore, prior CABG (OR 0.12 [0.04–0.34]), and in-hospital revascularization (OR 0.05 [0.01–0.189]) was protective against mortality. In the multivariate analysis, independent predictors of in-hospital mortality were age (OR 1.13 [1.05–1.22] for every year increase in age); diabetes (OR 6.35 [1.61–24.97]) and cardiogenic shock at presentation (OR 10.0 [2.33–42.95]). Again, revascularization during hospitalization (OR 0.02 [0.003–0.12]) conferred a protective effect. The overall complication rate was low (8.5%). CONCLUSIONS: Patients requiring IABC represent a high-risk group with substantial in-hospital mortality. Despite this high mortality, over two-thirds of patients do leave the hospital alive, suggesting that IABC is a feasible therapeutic device, even in a developing country

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Spontaneous coronary artery dissection: a rare cause of acute coronary syndrome

Spontaneous coronary artery dissection (SCAD) is an uncommon and rare cause of acute coronary syndrome (ACS) and sudden cardiac death. A number of conditions and diseases are associated with SCAD. Various risk factors for SCAD include pregnancy, intensive exercise, cocaine abuse and connective tissue disorders like Ehlers-Danlos disease, and Marfan\u27s Syndrome. We present here a case of SCAD which presented with atrial fibrillation and acute coronary syndrome in an unusual presentation. A 71 year man, who was a known case of hypertension and dyslipidemia, presented to the emergency department with typical cardiac chest pain and palpitations of 2 hours duration. The examination revealed a pulse of 138 bpm irregularly irregular, BP 115/75 mmHg, variable first and normal second heart sounds. The lungs were clear on auscultation. The electrocardiogram revealed atrial fibrillation with rapid ventricular rate. His heart rate was controlled with beta blockers and treatment commenced for acute coronary syndrome including anticoagulation. His base line blood reports were within normal limits and two serial Troponin I tests were negative. Coronary angiogram was done which showed dissection of the left coronary system including the left anterior descending artery from ostium to mid portion and extending to the diagonal branch. The left circumflex artery also showed dissection going into the obtuse marginal branch. The right coronary artery showed plaque formation with 30 to 40% stenosis without any dissection. The patient underwent CABG on the same day on an emergent basis. Post procedure he suffered a limited stroke from which he recovered uneventfully. He was discharged home after recovery and is being followed in the clinic where he is doing well. Keywords: spontaneous, dissection, CAD, atrial fibrillation, myocardial infarctio