面向工业产品外型概念设计系统的研究

为了实现一个基于手绘草图且具备友好交互界面支持概念的设计系统,文章根据该系统需要完成设计不同的功能,采用分不同模块进行系统分析与设计,包括草绘设计环境的设计模块、二维笔画识别与草图规整模块、图形显示模块。本系统克服传统CAD设计工具的特点,结合现有的草图设计技术,构建二维草图技术体系。     

应用抽油机节能变速器实现稠油低冲次井的节能降耗

许多稠油井抽油机因为油稠、负荷重，必须采用低冲次采油，现场应用较多的是磁调速电机来调整冲次．虽然能够达到降低冲次的目的，但是电机损耗较高。抽油机节能变速器是一种针对低冲次高耗井的节能装置，是磁调速电机的替代产品。通过变速装置降低电机对抽油机变速箱的传递速度，改变电机扭矩，降低了电动机运行的均方根电流；既能达到到低冲次采油的目的，又有明显的节能效果。     

Evaluating the cost-effectiveness of percutaneous closure of a patent foramen ovale versus medical management in patients with a cryptogenic stroke: from the UK payer perspective

Aims: Percutaneous closure of a patent foramen ovale (PFO) is known to lower the risk of recurrent stroke in patients with a cryptogenic stroke. However, the economic implications of transcatheter PFO closure are less well known. From a UK payer perspective, a detailed economic appraisal of PFO closure was performed for prevention of recurrent ischemic stroke in patients with a PFO who had experienced a cryptogenic stroke.

Materials and methods: A Markov cohort model was constructed using a 5-year time-horizon with a patient mean age of 45.2 years, reflecting the characteristics reported in the REDUCE trial. Transition probabilities, clinical inputs, costs, and utility values were ascertained from published and national costing sources. Total costs, incremental costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated, utilizing a discount rate of 3.5%. A range of univariate and probabilistic sensitivity analyses were also performed.

Results: When applying a willingness-to-pay (WTP) threshold of £20,000/QALY in accordance with NICE guidelines, PFO closure compared with antiplatelet therapy alone showed a beneficial cost/QALY of £18,584, attained at 4 years. Applying discount rates of 0% and 6% had a negligible effect on the base-case model findings. PFO closure demonstrated a 76.9% probability of being cost-effective at a WTP threshold of £20,000/QALY at a 5-year time-horizon.

Limitations: This model focused specifically on UK stroke patients and typically enrolled young (mean age <65 years old) patients. Hence, caution should be taken when comparing data vs non-UK populations, and it remains unclear how older patients might have affected cost-effectiveness findings, as the risk of paradoxical embolism can persist as patients age.

Conclusion: Percutaneous closure of a PFO is cost-effective compared with antiplatelet therapy alone, underlining the economic benefits potentially afforded by this treatment in selected patients.     

Number needed to treat based on real-world evidence for non-vitamin K antagonist oral anticoagulants versus vitamin K antagonist oral anticoagulants in stroke prevention in patients with non-valvular atrial fibrillation

Aims: Non-vitamin K antagonist oral anticoagulants (NOACs) and vitamin K antagonists (VKAs) are used to prevent stroke in patients with atrial fibrillation (AF). This paper aimed to evaluate the clinical efficacy and safety of NOACs when compared to VKAs by calculating the number needed to treat (NNT) at 2 years using incidence rates and hazard ratios (HRs) derived from a meta-analysis of studies conducted in real-world settings.

Materials and methods: HRs were sourced from a published systematic literature review and a meta-analysis of real-world evidence on the use of NOACs vs VKAs. Rivaroxaban, dabigatran, and apixaban vs VKAs were investigated. The efficacy outcomes included: a composite of ischaemic stroke and systemic embolism (IS/SE), ischaemic stroke (IS), and all-cause mortality. The safety analysis assessed major bleeding and intracranial haemorrhage (ICH).

Results: Superiority of NOACs vs VKAs was observed in 10/15 comparisons. Treating patients with rivaroxaban and dabigatran was associated with a reduced risk of IS and all-cause mortality compared to VKAs, with one death prevented every 22 and 32 patients, respectively, and one IS prevented every 206 and 166 patients, respectively. Rivaroxaban was significantly associated with a reduced risk of IS/SE compared to VKA (NNT: 107). No significant differences were observed between apixaban and VKAs. Dabigatran and apixaban were associated with a reduced risk of major bleeding compared to VKA (NNT: 59 and 38, respectively). No significant difference was observed between rivaroxaban and VKAs regarding major bleeding. Rivaroxaban, dabigatran, and apixaban were significantly associated with a reduced risk of ICH (NNT: 205, 115, and 108, respectively).

Limitations: Heterogeneity in definitions of major bleeding across studies.

Conclusions: The NNT calculation, when approached and interpreted properly, is a practical measure of the effectiveness of a treatment. The calculation based on HRs showed that NOACs are safe and effective alternatives to VKAs in real life.     

Cost-effectiveness of percutaneous patent foramen ovale closure as secondary stroke prevention

Objective: Compared to medical therapy alone, percutaneous closure of patent foramen ovale (PFO) further reduces risk of recurrent ischemic strokes in carefully selected young to middle-aged patients with a recent cryptogenic ischemic stroke. The objective of this study was to evaluate the cost-effectiveness of this therapy in the context of the United Kingdom (UK) healthcare system.

Methods: A Markov cohort model consisting of four health states (Stable after index stroke, Post-Minor Recurrent Stroke, Post-Moderate Recurrent Stroke, and Death) was developed to simulate the economic outcomes of device-based PFO closure compared to medical therapy. Recurrent stroke event rates were extracted from a randomized clinical trial (RESPECT) with a median of 5.9-year follow-up. Health utilities and costs were obtained from published sources. One-way and probabilistic sensitivity analyses (PSA) were performed to assess robustness. The model was discounted at 3.5% and reported in 2016 Pounds Sterling.

Results: Compared with medical therapy alone and using a willingness-to-pay (WTP) threshold of £20,000, PFO closure reached cost-effectiveness at 4.2 years. Cost-effectiveness ratios (ICERs) at 4, 10, and 20 years were ?20,951, ?6,887, and ?2,158, respectively. PFO closure was cost-effective for 89% of PSA iterations at year 10. Sensitivity analyses showed that the model was robust.

Conclusions: Considering the UK healthcare system perspective, percutaneous PFO closure in cryptogenic ischemic stroke patients is a cost-effective stroke prevention strategy compared to medical therapy alone. Its cost-effectiveness was driven by substantial reduction in recurrent strokes and patients’ improved health-related quality-of-life.     

Addressing shortfalls in TIA care in the UK: an economic perspective

Abstract

Objective: To estimate the clinical outcomes and costs associated with reconfiguring the management of TIA in the UK to offer patients rapid access to outpatient clinics for specialist assessment and treatment.

Methods: An economic deterministic model was run comparing two pathways – one arm representing current clinical care based on national guidelines and clinical practice and patient referral to a weekly outpatient clinic, and a revised care pathway replicating phase 2 of the EXPRESS study with patient referral to a daily outpatient clinic. The outcomes of the model were measured in terms of recurrent strokes avoided and net budget impact to secondary care.

Results: Reconfiguring TIA care pathways in the UK could result in the avoidance of 8,164 recurrent stroke events. The model predicts savings of £25,573,279 for the UK healthcare system over 12 months. Annual net savings are predicted in England (£24,916,011), Scotland (£80,554) and Northern Ireland (£1,041,817). In Wales, increased costs of £450,435 are estimated.

Limitations: Using the data published from the EXPRESS study, it is not possible to model a stepwise approach to implementing the revised TIA care pathway. It is therefore assumed that it would be possible to implement the revised TIA care pathway as detailed in the EXPRESS study across the UK and achieve the reduction in recurrent stroke risk that was reported.

Conclusions: The model suggests that the reconfiguration of TIA care pathways in the UK to offer rapid access to treatment and assessment could prevent TIA-related future stroke events and potentially result in cost savings to the healthcare system.     

Cost-effectiveness of Access to Critical Cerebral Emergency Support Services (ACCESS): a neuro-emergent telemedicine consultation program

Aims: Access to Critical Cerebral Emergency Support Services (ACCESS) was developed as a low-cost solution to providing neuro-emergent consultations to rural hospitals in New Mexico that do not offer comprehensive stroke care. ACCESS is a two-way audio-visual program linking remote emergency department physicians and their patients to stroke specialists. ACCESS also has an education component in which hospitals receive training from stroke specialists on the triage and treatment of patients. This study assessed the clinical and economic outcomes of the ACCESS program in providing services to rural New Mexico from a healthcare payer perspective.

Methods: A decision tree model was constructed using findings from the ACCESS program and existing literature, the likelihood that a patient will receive a tissue plasminogen activator (tPA), cost of care, and resulting quality adjusted life years (QALYs). Data from the ACCESS program includes emergency room patients in rural New Mexico from May 2015 to August 2016. Outcomes and costs have been estimated for patients who were taken to a hospital providing neurological telecare and patients who were not.

Results: The use of ACCESS decreased neuro-emergent stroke patient transfers from rural hospitals to urban settings from 85% to 5% (no tPA) and 90% to 23% (tPA), while stroke specialist reading of patient CT/MRI imaging within 3?h of onset of stroke symptoms increased from 2% to 22%. Results indicate that use of ACCESS has the potential to save $4,241 ($3,952–$4,438) per patient and increase QALYs by 0.20 (0.14–0.22). This increase in QALYs equates to ～73 more days of life at full health. The cost savings and QALYs are expected to increase when moving from a 90-day model to a lifetime model.

Conclusion: The analysis demonstrates potential savings and improved quality-of-life associated with the use of ACCESS for patients presenting to rural hospitals with acute ischemic stroke (AIS).     

关于汉语字典按笔顺编排条目的建议

批评了现有的字典检字法,提出按笔顺编排字典条目的建议,认为按笔顺编排不仅有利于条目排序,还能被用来快速检字,且能避免方言读音的障碍,有利于字典事业的健康发展。     

Clinical and economic impact of rivaroxaban on the burden of atrial fibrillation: The case study of Japan

Objectives: Atrial fibrillation (AF) affects an estimated 1.5 million individuals in Japan, increasing their stroke risk and imposing considerable costs on the Japanese healthcare system. To reduce stroke incidence, guidelines recommend using anticoagulants in moderate-to-high risk non-valvular AF (NVAF) patients; however, many patients receive no treatment, aspirin only, or remain poorly-controlled on vitamin K antagonists (VKAs) due to high VKA discontinuation rates and non-adherence to guidelines. A prevalence-based Markov model was developed to estimate the clinical and budgetary impact of treating these patients with Xarelto^TM (rivaroxaban, Bayer AG) in Japan.

Methods: Population, baseline risk of events, and associated management costs were estimated using data from Japanese publications where available. Treatment efficacy and safety were derived from published data and the J-ROCKET AF trial. Drug and physician visit costs were based on data from the Ministry of Health, Labor, and Welfare, the J-ROCKET AF trial, and Japanese clinical guidelines.

Results: This model demonstrates that increased use of rivaroxaban in inadequately-managed NVAF patients could avoid 456 081 non-fatal ischemic strokes (IS) and 76 975 cardiovascular deaths over 10 years in Japan. This clinical benefit offsets the increased incidence of myocardial infarctions and anticoagulant-related bleeding. Decreased event costs could lead to a ¥188.4 billion decrease in net spending over the analysis time horizon.

Conclusions: Introducing rivaroxaban may decrease the burden of NVAF in Japanese society. From a clinical perspective, the reduction in IS and embolic events outweighs the increased risk of anticoagulant-related bleeding; from an economic perspective, reduced event costs offset drug and physician visit costs, resulting in cost savings.     

One-year follow-up healthcare costs of patients hospitalized for transient ischemic attack or ischemic stroke and discharged with aspirin plus extended-release dipyridamole or clopidogrel

Abstract

Objective:

To examine healthcare costs among patients hospitalized for transient ischemic attack or ischemic stroke (TIA/stroke) and prescribed aspirin plus extended-release dipyridamole (ASA-ERDP) or clopidogrel (CLOPID) within 30 days post-discharge using a retrospective claims database from a large US managed care organization.

Methods:

Adult patients with ≥1 hospitalizations for TIA/stroke between January 2007–July 2009 and ≥1 claims for an oral anti-platelet (OAP) were observed for 1 year before and after the first TIA/stroke hospitalization or until death, whichever came first. Cohorts were defined by the first claim for ASA-ERDP or CLOPID within 30 days post-discharge. A generalized linear model, adjusting for demographics, baseline comorbidities and costs, compared total follow-up costs (medical?+?pharmacy) between ASA-ERDP and CLOPID patients.

Results:

Of 6377 patients (2085 ASA-ERDP; 4292 CLOPID) who met the selection criteria, mean (SD) age was 69 (13) years and 50% were male. Unadjusted mean total follow-up costs were lower for ASA-ERDP than CLOPID ($26,201 vs $30,349; p?=?0.002), of which average unadjusted medical and pharmacy costs were $22,094 vs $26,062 (p?=?0.003) and $4107 vs $4288 (p?=?0.119), respectively. Multivariate modeling indicated that the following were associated with higher total costs (all p?<?0.05): higher baseline Quan-Charlson comorbidity score, history of atrial fibrillation and myocardial infarction, index stroke hospitalization, death post-discharge, and index CLOPID use. Adjusted mean total follow-up costs for CLOPID were 9% higher than ASA-ERDP (cost ratio: 1.09; p?=?0.038).

Conclusion:

In this study, compared to CLOPID patients, ASA-ERDP patients were observed to have lower total costs 1 year post-discharge TIA/stroke hospitalization, driven primarily by lower medical costs. Further research into the real-world impact of OAP therapies on clinical and economic outcomes of patients with stroke/TIA is warranted. The findings of this study should be considered within the limitations of an administrative claims analysis, as claims data are collected for the purpose of payment.