Utility of applying a diagnostic algorithm in giant cell arteritis based on the level of clinical suspicion

INTRODUCTION

To reach the diagnosis of giant cell arteritis (GCA), signs, symptoms, laboratory tests, imaging findings, and occasionally anatomopathological results from temporal artery biopsy are evaluated. This study describes the results of an algorithm analysis based on clinical and ultrasound evaluation of patients with suspected GCA, highlighting its diagnostic utility by contrasting its use in different clinical suspicion scenarios.

METHOD

Prospective multicenter study evaluating patients referred with suspected GCA through a preferential circuit (fast track), grouping them according to low or high clinical suspicion of GCA. Each of these scenarios is evaluated by biopsy and ultrasound for all patients, resulting in positive, indeterminate, or negative outcomes, yielding six possible groups. Potential areas of improvement are explored, emphasizing that, following a negative or indeterminate ultrasound, 18-FDG-PET-CT could be recommended. We analyze the results and application of a diagnostic algorithm, confirming its efficiency and applicability based on whether there is high or low clinical suspicion.

RESULTS

Sixty-nine patients (41 in the high suspicion group and 28 in the low suspicion group). There were 41 new diagnoses of GCA: 35 in the high suspicion group and 6 in the low suspicion group. Using ultrasound alone, the initial algorithm has an overall diagnostic efficiency of 72.5%, which improves to 80.5% when including 18F-FDG-PET/CT. The negative predictive value of ultrasound in patients with low clinical suspicion is 84.6%, and the positive predictive value of ultrasound in patients with high suspicion is 100%, improving sensitivity from 57.1% to 80.8% with 18F-FDG-PET/CT in this scenario. Temporal artery biopsy was performed on all patients, with no differences in sensitivity or specificity compared to ultrasound. In cases where all three tests - ultrasound, biopsy, and 18F-FDG-PET/CT - are performed, sensitivity increases to 92.3% in patients with high clinical suspicion.

CONCLUSION

In situations of high clinical suspicion, the algorithm provides sufficient information for the diagnosis of GCA if ultrasound is positive. A negative ultrasound is sufficient to rule out the diagnosis in the context of low clinical suspicion. 18-FDG-PET-CT may be useful in patients with high suspicion and negative or indeterminate ultrasound results.

Hybrid Controller Based on Numerical Methods for Chemical Processes with a Long Time Delay

A hybrid control framework is proposed as an alternative for long time delays in chemical processes. The hybrid approach mixes the numerical methods in an internal mode control (IMC) structure, which uses the particle swarm optimization (PSO) algorithm to improve the adjustment of the controller parameters. Simulation tests are carried out on linear systems of high order and inverse response, both with dominant delay, and tests on a nonlinear process (chemical reactor). The performance of the proposed controller is stable and satisfactory despite nonlinearities in various operating conditions, set-point changes, process disturbances, and modeling errors. In addition, experimental tests were performed on a setup composed of two heaters and two temperature sensors mounted on an Arduino microcontroller-based board called the Temperature Control Laboratory (TCLab), with an additional software delay introduced. The merits and drawbacks of each scheme are analyzed using radar charts, comparing the control methods with different performance measures for set-point and disturbance changes. Furthermore, the new controller uses PSO to improve the tuning parameters.

Dual-Mode Based Sliding Mode Control Approach for Nonlinear Chemical Processes

This paper synthesizes a new sliding mode controller (SMC) approach to enhance tracking and regulation tasks by following dual-mode concepts. The new control law consists of two distinct types of operation, using the combination of higher gain to large error signals (transient) and lower gain to small error signals (the region around the set point). The design is presented from a dual-mode (PD-PID) sliding surface operating in concert, fulfilling desired control objectives to ensure stability and performance. Therefore, a new controller was established, and we called it a dual-mode based SMC. The proposed controller is tested by computer simulations applied to two nonlinear processes, a continuous stirred-tank reactor (CSTR) and a mixing tank with a variable dead time. The results are compared with two different alternatives of SMC. In addition, the merits and drawbacks of the control schemes are analyzed using radial graphs, comparing the control methods with various performance measures for set points and disturbances changes. The ITSE (integral of time multiplied by the squared error), TVu (total variation of control effort) indices, Mp (maximum overshoot), and ts (settling time) were the indices used for performance analysis and comparisons.

Hybrid Approaches-Based Sliding-Mode Control for pH Process Control

This paper presents two hybrid control topologies; the topologies are designed by combining artificial intelligence approaches and sliding-mode control methodology. The first topology mixes the learning algorithm for multivariable data analysis (LAMDA) approach with sliding-mode control. The second offers a Takagi-Sugeno multimodel approach, internal model, and sliding-mode control. The process under study is a nonlinear pH neutralization process with high nonlinearities and time-varying parameters. The pH process is simulated for multiple reference changes, disturbance rejection, and noise in the transmitter. Performance indices are used to compare the proposed approaches quantitatively. The hybrid control topologies enhance the performance and robustness of the pH process under study.

AB0384 IMPACT OF TEMPORAL ARTERY ULTRASOUND ON SURVIVAL OF PATIENTS WITH GIANT CELL ARTERITIS

Background:

Giant cell arteritis (GCA) is the most common primary systemic vasculitis in adults over 50 years of age. Its incidence increases with age, with a peak between 70-80 years and predominates in women, 3:1. It is a medical emergency that, if not diagnosed, can lead to irreversible complications. The delay in time from diagnosis to start of treatment is crucial to avoid possible serious outcomes on short, medium and long term. Survival in GCA is estimated between 60-90% at 5 years and 48-81% at 10 years. Efforts have been made to implement rapid diagnostic circuits to assess patients and initiate treatment without delay with good results both in reducing permanent vision loss and in reducing the costs of these patients due to emergency visits and admissions. The morbidity and mortality of this disease is high, but the use of efficient diagnostic strategies, such as ultrasound of superficial temporal arteries, has proven to be a useful, practical, cost-effective and, above all, quick tool to make the diagnostic approach.

Objectives:

Analyze the impact of early temporal artery ultrasound on survival for patients with GCA.

Methods:

Survival study of 48 patients with GCA, in two different “stages” in terms of diagnostic approach: Group A (n = 27), patients diagnosed between 2002 - 2011 using only ACR 1990 criteria and Group E (n = 21) diagnosed between 2010-2015 using ACR criteria and TAUS. TAUS was performed by Rheumatologists with extensive experience in ultrasound and within a period of no more than 7 days for these patients. The definitive diagnosis of GCA was based on the clinical criteria of the Rheumatologist within the clinical and analytical context and with the specific complementary examinations for each case (Ultrasound, PET-CT, biopsy). Demographic data, comorbidities, signs and symptoms at debut, analytical data, complementary examinations, treatment and evolution were obtained retrospectively through the electronic medical record of the patient, based on the database of our GCA cohort. A survival analysis was performed considering death as the main outcome. The statistic used was the Kaplan-Meier test. In addition, other complications related to treatment or pathology are collected.

Results:

The mean age at diagnosis of our patients was 79 + - 6 years, with a female: male ratio of 3: 1. The follow-up was between 2 and 16 years with a mean of 5.8 + - 3 years, until the last visit collected or until the outcome of death. Group A had a survival at 5 and 10 years of 53.4% and 36.7% respectively, while group E of 79.5% at both cut-off points. (Figure 1).

There is a significant difference between the survival of both groups, p <0.01, this being better in the group in which TAUS was implemented for rapid diagnosis (group E). The main causes of death were cardiovascular events, 30%, predominantly in group E (75%), and infection, 30%, predominantly in group A. The median from diagnosis to death was 3 years (range 1 - 13).

Figure 1.

Group A (red line) according to ACG 1990 criteria and Group B (green line) according to ACG criteria and implementing TAUS for rapid diagnosis

Conclusion:

The implementation of temporal artery ultrasound (TAUS) is associated with a significant improvement in the survival rate of patients with GCA and a reduction in treatment-related complications in patients who were diagnosed with ultrasound in less than 7 days compared to those diagnosed by the conventional healthcare attention routes.

References:

[1]Gonzalez-Gay MA, et al. Giant cell arteritis: epidemiology, diagnosis, and management. DOI: 10.1007/s11926-010-0135-9

[2]Patil P, et al. Fast track pathway reduces sight loss in giant cell arteritis: results of a longitudinal observational cohort study. PMID: 26016758

[3]Breuer GS, et al. Survival of patients with giant cell arteritis: a controversial issue. PMID: 31969222

[4]Diamantopoulos AP, et al. The fast-track ultrasound clinic for early diagnosis of giant cell arteritis significantly reduces permanent visual impairment: towards a more effective strategy to improve clinical outcome in giant cell arteritis? 10.1093/rheumatology/kev289

Disclosure of Interests:

None declared

Estimating the Population Health Impact of Recently Introduced Modified Risk Tobacco Products: A Comparison of Different Approaches

Introduction

Various approaches have been used to estimate the population health impact of introducing a Modified Risk Tobacco Product (MRTP).

Aims and Methods

We aimed to compare and contrast aspects of models considering effects on mortality that were known to experts attending a meeting on models in 2018.

Results

Thirteen models are described, some focussing on e-cigarettes, others more general. Most models are cohort-based, comparing results with or without MRTP introduction. They typically start with a population with known smoking habits and then use transition probabilities either to update smoking habits in the “null scenario” or joint smoking and MRTP habits in an “alternative scenario”. The models vary in the tobacco groups and transition probabilities considered. Based on aspects of the tobacco history developed, the models compare mortality risks, and sometimes life-years lost and health costs, between scenarios. Estimating effects on population health depends on frequency of use of the MRTP and smoking, and the extent to which the products expose users to harmful constituents. Strengths and weaknesses of the approaches are summarized.

Conclusions

Despite methodological differences, most modellers have assumed the increase in risk of mortality from MRTP use, relative to that from cigarette smoking, to be very low and have concluded that MRTP introduction is likely to have a beneficial impact. Further model development, supplemented by preliminary results from well-designed epidemiological studies, should enable more precise prediction of the anticipated effects of MRTP introduction.

Implications

There is a need to estimate the population health impact of introducing modified risk nicotine-containing products for smokers unwilling or unable to quit. This paper reviews a variety of modeling methodologies proposed to do this, and discusses the implications of the different approaches. It should assist modelers in refining and improving their models, and help toward providing authorities with more reliable estimates.

Descripción morfométrica y faneroptica de la cabra “Chusca lojana” del bosque seco del Sur del Ecuador

En la Región Sur del Ecuador se encuentra la zona del bosque seco que abarca desde los 100 metros sobre el nivel del mar (m.s.n.m) hasta los 1200 m.s.n.m, lugar donde se ha adaptado la cabra criolla llamada “Chusca lojana”. El presente trabajo tuvo como objetivo la caracterización fenotípica de este recurso zoogenético, permitiendo disponer de un patrón o estándar racial con fines de identificación, estudio, selección y mejoramiento de esta población. La investigación comprendió una muestra de 163 cabras adultas manejadas en ambiente extensivo, considerando 21 medidas morfométricas y 10 características fanerópticas; para el análisis morfométrico se aplicó una estadística no paramétrica con el Test de Kruskal-Wallis considerando como variables el sexo y los biotipos. Los resultados permitieron identificar 4 biotipos, que de acuerdo a ciertas características peculiares que presentan a nivel de cabeza y orejas se las ha identificado como: Chusca “oreja corta y doblada”, Chusca “oreja de león”, Chusca oreja “torneada” y Chusca “muca”; en el aspecto faneróptico presentan cuernos opistoceros (58%) y ortoceros (37%), siendo un 22% acornes (biotipo Chusca muca), poseen barba y mamelas el 26 y 29%, respectivamente, presentando estas dos características un dimorfismo en favor de los machos; la mayoría de esta población presenta un perfil de rostro recto (67%) y subcóncavo (28%); la forma de la ubre es globosa (64%), el color de pezones (93%) y cascos (87%) es pigmentado; los machos presentan testículos pendulosos (70%) y una característica peculiar es que poseen un escroto dividido en dos sacos (40%). En conclusión, la cabra Chusca es un animal con una tendencia productiva más a leche que a carne, destacando su capacidad torácica que le permite recorrer con facilidad por la topografía irregular de la zona en busca de alimento.

Hyperbaric oxygen for radiation-induced cystitis: A long-term follow-up

INTRODUCTION AND OBJECTIVES

Bladder complications may be seen in up to 12% of patients treated with pelvic irradiation. Hyperbaric oxygen therapy (HBOT) is an option for the management of radiation-induced hemorrhagic cystitis (RIHC). The aim of this study was to evaluate the efficacy of HBOT in radiation cystitis and to identify the predictive factors for a successful outcome.

MATERIAL AND METHODS

We retrospectively reviewed 105 patients diagnosed with RIHC which were treated with HBOT between 2007 and 2016 in our institution. Patients received 100% oxygen in a multiplace hyperbaric chamber at 2.4atm for 80minutes. All patients fulfilled a questionnaire documenting symptom severity pre-HBOT and at the end of the follow-up period.

RESULTS

After a median of 40 HBOT sessions, there was success rate of 92,4% in the control of hematuria. During our follow-up period (median of 63 months) 24,7% patients presented with recurrence of hematuria. The mean score of the questionnaire-assessed variables: dysuria, urinary frequency and hematuria, was significantly lower after the follow-up period (P<.05). Our data shows that the sooner HBOT is delivered after the first episode of hematuria, better response rates are achieved and lower recurrences concerning hematuria were registered (P<.05). No serious complications were observed.

CONCLUSIONS

Our results support the safety and long-term benefits of HBOT on RIHC and other distressful bladder symptoms, which represents an expected improvement of quality of life in our patients.

Rheumatoid Arthritis Initiating as Palindromic Rheumatism: A Distinct Clinical Phenotype?

Objective.

To analyze the prevalence of preexisting palindromic rheumatism (PR) in patients with established rheumatoid arthritis (RA) and to evaluate whether these patients have a distinctive clinical and serological phenotype.

Methods.

Cross-sectional study in patients with established RA. Preexisting PR was determined using a structured protocol and confirmed by retrospective review of medical records. Demographic, clinical, radiological, immunological, and therapeutic features were compared in patients with and without PR.

Results.

Included were 158 patients with established RA (78% female) with a mean disease duration since RA onset of 5.1 ± 2.7 years. Preexisting PR was recorded in 29 patients (18%). The median time from the onset of PR to progression to RA was 1.2 years. No between-group differences in demographic features, current disease activity, radiographic erosive disease, or disability were observed. Patients with PR had a higher prevalence of smoking (72% vs 40%). Positive rheumatoid factor, anticitrullinated peptide antibodies, and anticarbamylated protein antibodies were numerically higher in patients with PR. No differences in treatment were observed except for greater hydroxychloroquine (HCQ) use in patients with PR (38% vs 6%). Palindromic flares persisted in a significant proportion of patients during the RA course, including patients in clinical remission or receiving biological disease-modifying antirheumatic drugs.

Conclusion.

Eighteen percent of patients with RA had a history compatible with PR previous to RA onset. No specific clinical or serological phenotype was identified in these patients, although higher HCQ use and smoking prevalence were identified. Palindromic flares may persist during the RA disease course despite treatment.

The influence of hyperbaric environment on the skeletal muscle mitochondrial energetic of rats after induced muscle contusion

OBJECTIVE

Analyze the influence of the hyperbaric environment on skeletal muscle mitochondrial bioenergetic end-points of rats submitted to muscle contusion.

METHODS

Twelve female Wistar rats were randomly assigned to three groups. All rats were submitted to muscle contusion in the right gastrocnemius through a standard protocol. The control group (C) remained under normobaric conditions without any treatment. The hyperbaric air (HB) and the hyperbaric oxygen (HBO2) groups had four sessions of HBO2 therapy 60 minutes, six, 12, 24 and 48 hours after the injury at 253.25 kPa (2.5 atmospheres absolute/ATA) with air or 100% oxygen, respectively. The animals were sacrificed 48 hours after muscle injury, and both muscles (injured and non-injured) were analyzed. Muscle mitochondrial bioenergetics and mitochondrial permeability transition pore (MPTP) susceptibility were evaluated.

RESULTS

Significant differences were found in all parameters between the injured and the non-injured gastrocnemius in the C group. In the HB group, significantly better results concerning bioenergetics-related end points with complex I and II substrates where found in the right gastrocnemius, whereas in the HBO2 group the time to Vmax (time that elapsed until the faster swelling kinetics starts) was significantly higher and the swelling amplitude was significantly smaller than in other groups, which suggest a lower susceptibility to MPTP opening.

CONCLUSION

The present data suggest that hyperbaric exposure, particularly with oxygen, positively modulates the efficiency of skeletal muscle mitochondria after muscle contusion.

Assessing modified risk tobacco and nicotine products: Description of the scientific framework and assessment of a closed modular electronic cigarette

Cigarette smoking causes many human diseases including cardiovascular disease, lung disease and cancer. Novel tobacco products with reduced yields of toxicants compared to cigarettes, such as tobacco-heating products, snus and electronic cigarettes, hold great potential for reducing the harms associated with tobacco use. In the UK several public health agencies have advocated a potential role for novel products in tobacco harm reduction. Public Health England has stated that "The current best estimate is that e-cigarettes are around 95% less harmful than smoking" and the Royal College of Physicians has urged public health to "Promote e-cigarettes widely as substitute for smoking". Health related claims on novel products such as 'reduced exposure' and 'reduced risk' should be substantiated using a weight of evidence approach based on a comprehensive scientific assessment. The US FDA, has provided draft guidance outlining a framework to assess novel products as Modified Risk Tobacco Products (MRTP). Based on this, we now propose a framework comprising pre-clinical, clinical, and population studies to assess the risk profile of novel tobacco products. Additionally, the utility of this framework is assessed through the pre-clinical and part of the clinical comparison of a commercial e-cigarette (Vype ePen) with a scientific reference cigarette (3R4F) and the results of these studies suggest that ePen has the potential to be a reduced risk product.

Super-twisting sliding mode differentiation for improving PD controllers performance of second order systems

Designing a proportional derivative (PD) controller has as main problem, to obtain the derivative of the output error signal when it is contaminated with high frequency noises. To overcome this disadvantage, the supertwisting algorithm (STA) is applied in closed-loop with a PD structure for multi-input multi-output (MIMO) second order nonlinear systems. The stability conditions were analyzed in terms of a strict non-smooth Lyapunov function and the solution of Riccati equations. A set of numerical test was designed to show the advantages of implementing PD controllers that used STA as a robust exact differentiator. The first numerical example showed the stabilization of an inverted pendulum. The second example was designed to solve the tracking problem of a two-link robot manipulator.

Hyperbaric oxygen effects on sports injuries

In the last decade, competitive sports have taken on a whole new meaning, where intensity has increased together with the incidence of injuries to the athletes. Therefore, there is a strong need to develop better and faster treatments that allow the injured athlete to return to competition faster than with the normal course of rehabilitation, with a low risk of re-injury. Hyperbaric therapies are methods used to treat diseases or injuries using pressures higher than local atmospheric pressure inside a hyperbaric chamber. Within hyperbaric therapies, hyperbaric oxygen therapy (HBO) is the administration of pure oxygen (100%) at pressures greater than atmospheric pressure, i.e. more than 1 atmosphere absolute (ATA), for therapeutic reasons. The application of HBO for the treatment of sports injuries has recently been suggested in the scientific literature as a modality of therapy either as a primary or an adjunct treatment. Although results have proven to be promising in terms of using HBO as a treatment modality in sports-related injuries, these studies have been limited due to the small sample size, lack of blinding and randomization problems. HBO seems to be promising in the recovery of injuries for high-performance athletes; however, there is a need for larger samples, randomized, controlled, double-blinded clinical trials combined with studies using animal models so that its effects and mechanisms can be identified to confirm that it is a safe and effective therapy for the treatment of sports injuries.

Clinical effectiveness of hyperbaric oxygen therapy for BK-virus-associated hemorrhagic cystitis after allogeneic bone marrow transplantation

Late-onset hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (HSCT) has been associated with BK virus (BKV). Antiviral drugs are of limited efficacy and the optimal treatment for HC has not yet been established. Hyperbaric oxygen (HBO) may benefit these patients. We, therefore, retrospectively evaluated the effectiveness of HBO therapy in 16 patients with HC after allogeneic HSCT. All 16 patients had macroscopic hematuria and BKV infection. Patients received 100% oxygen in a hyperbaric chamber at 2.1 atmospheres for 90 min, 5 days per week, with a median 13 treatments (range, 4-84). Fifteen patients (94%) showed complete resolution of hematuria. Median urinary DNA BKV titers declined after HBO (P<0.05). Patients started on HBO earlier after diagnosis of HC responded sooner (P<0.05). HBO was generally well tolerated and proved to be a reliable option for this difficult to manage condition.

Some long time delay sliding mode control approaches

This paper presents a combined approach of predictive structures with sliding mode control (SMC). Control schemes have been proposed looking for performance and robustness improvement. These structures were designed for processes that can be approximated either by a first order plus time delay or an integral first order plus time delay model broadly used on chemical processes. The proposed schemes were tested for performance and robustness against set point changes and disturbances as compared with classical approaches.

Fuzzy surface-based sliding mode control

A new controller based on a combination of Sliding Mode Control and Fuzzy Logic is proposed. The conventional sliding surface is modified using a set of fuzzy rules. This combination confers controller robustness and flexibility. A neutralization process and a mixing process are used to compare the performance of the new controller to that of a conventional sliding mode controller and a PID controller.

Smith predictor based-sliding mode controller for integrating processes with elevated deadtime

An approach to control integrating processes with elevated deadtime using a Smith predictor sliding mode controller is presented. A PID sliding surface and an integrating first-order plus deadtime model have been used to synthesize the controller. Since the performance of existing controllers with a Smith predictor decrease in the presence of modeling errors, this paper presents a simple approach to combining the Smith predictor with the sliding mode concept, which is a proven, simple, and robust procedure. The proposed scheme has a set of tuning equations as a function of the characteristic parameters of the model. For implementation of our proposed approach, computer based industrial controllers that execute PID algorithms can be used. The performance and robustness of the proposed controller are compared with the Matausek-Micić scheme for linear systems using simulations.

A sliding mode control proposal for open-loop unstable processes

This papers presents a sliding mode controller based on a first-order-plus-dead-time model of the process for controlling open-loop unstable systems. The proposed controller has a simple and fixed structure with a set of tuning equations as a function of the desired performance. Both linear and nonlinear models were used to study the controller performance by computer simulations.

Development of a GPC-based sliding mode controller

This article presents a sliding mode controller that uses a generalized predictive controller in the reaching mode. The proposed predictive sliding mode controller is developed from a first-order-plus-deadtime model that represents a good approximation to many chemical processes. The predictive sliding mode controller has six tuning parameters and the tuning rules are given in the paper. Four simulation examples show the features of the proposed controller, which overcomes some of the disadvantages of sliding mode control and generalized predictive control strategies.

[Implantation of an intra-hospital resuscitation program]

The authors present their own experience on the installation of an in-hospital resuscitation programme, in a new tertiary hospital with 400 beds, an ICU with 8 beds and an emergency room 24 hours per day. The most important features presented are: the support by the Board of the Hospital, the engagement of all the health professionals, the distribution standardization and maintenance of the resuscitation equipment, the training in basic life-support techniques the doctors and nurses in the hospital, the performance of the cardiac arrest teams, all of which are fundamental to the maintenance of the chain of survival of cardiopulmonary resuscitation.

Sliding mode control: an approach to regulate nonlinear chemical processes

A new approach for the design of sliding mode controllers based on a first-order-plus-deadtime model of the process, is developed. This approach results in a fixed structure controller with a set of tuning equations as a function of the characteristic parameters of the model. The controller performance is judged by simulations on two nonlinear chemical processes.