A Multi-Year Study of the Safety and Training Impacts of Introducing the Live, Virtual, Constructive Training Strategy into Navy Air Combat

In the Navy’s proposed Live, Virtual, Constructive (LVC) training system, virtual entities that represent pilots in flight simulators and computer-generated constructive entities will be injected into the cockpits of F/A-18 aircraft during live-flight training. The Navy expects LVC to ameliorate many of the economic and environmental impacts of live-flight training and to support future training requirements. However, the potential impact of LVC on training effectiveness and safety is not completely understood. While the naval air combat training system is notably robust, its inherent complexity precludes a straightforward analysis of potential hazards and mitigations. Two years ago, researchers began to identify and assess the numerous human-technology interactions that will characterize the future LVC training system, most notably those that could lead to hazardous LVC training situations. They employed cognitive task analysis methods to interview fighter pilots, F/A-18 weapons systems officers, range training officers, and modeling and simulation subject-matter experts (SMEs). The present paper is a follow-up to their 2013 ISAP presentation on potential LVC training hazards and mitigations identified during Cycle I of their iterative research. An additional two-year cycle of data collection, analysis, and SME review has led to an enriched understanding of the potential training hazards and benefits that could arise from interactions among training system elements. The long-term goal of this research is to develop requirements for the Navy’s LVC training system that will enable its safe implementation and eventual optimization. With that goal in mind, the findings from Cycle II are presented here

Management of atherothrombosis with clopidogrel in high-risk patients with recent transient ischaemic attack or ischaemic stroke (MATCH): study design and baseline data.

BACKGROUND: The CAPRIE study showed the superiority of clopidogrel over acetylsalicylic acid (ASA) for reducing the combined risk of major atherothrombotic events in patients with recent myocardial infarction (MI), recent ischaemic stroke (IS) or established peripheral arterial disease. The benefit of clopidogrel over ASA is amplified in high-risk patients. Proof of concept for the benefit of clopidogrel in addition to ASA in patients with coronary manifestations of atherothrombosis was provided by the CURE trial. METHODS: MATCH is a randomized, double-blind, placebo-controlled trial that compares clopidogrel and ASA versus clopidogrel alone in high-risk patients with recently symptomatic cerebrovascular disease. Eligible patients have experienced a transient ischaemic attack (TIA) or IS within the last 3 months and have evidence of at least 1 additional risk factor within the last 3 years (prior IS, MI, stable or unstable angina pectoris, diabetes or symptomatic peripheral arterial disease). Patients were randomized to receive ASA 75 mg once daily or placebo, with both groups receiving clopidogrel 75 mg once daily as part of standard therapy. The primary end point is the composite of IS, MI, vascular death and rehospitalization for an acute ischaemic event. The duration of treatment and follow-up is 18 months for each patient. RESULTS: Enrollment was completed in April 2002, with 7,599 patients randomized to receive the study medication. The mean age at randomization was 66 years, and the qualifying event was IS in 78.9% of patients and TIA in 21.1%. The baseline features of the study cohort indicate a population that is at a high risk for atherothrombotic recurrence. CONCLUSION: MATCH is a major ongoing trial that will provide important data on the benefit of clopidogrel and ASA compared with clopidogrel alone for reduction of vascular ischaemic events in patients with recent TIA or IS who are at high risk of atherothrombotic event recurrence

Extending thrombolysis to 4·5–9 h and wake-up stroke using perfusion imaging: a systematic review and meta-analysis of individual patient data

Background: Stroke thrombolysis with alteplase is currently recommended 0–4·5 h after stroke onset. We aimed to determine whether perfusion imaging can identify patients with salvageable brain tissue with symptoms 4·5 h or more from stroke onset or with symptoms on waking who might benefit from thrombolysis. Methods: In this systematic review and meta-analysis of individual patient data, we searched PubMed for randomised trials published in English between Jan 1, 2006, and March 1, 2019. We also reviewed the reference list of a previous systematic review of thrombolysis and searched ClinicalTrials.gov for interventional studies of ischaemic stroke. Studies of alteplase versus placebo in patients (aged ≥18 years) with ischaemic stroke treated more than 4·5 h after onset, or with wake-up stroke, who were imaged with perfusion-diffusion MRI or CT perfusion were eligible for inclusion. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] score 0–1) at 3 months, adjusted for baseline age and clinical severity. Safety outcomes were death and symptomatic intracerebral haemorrhage. We calculated odds ratios, adjusted for baseline age and National Institutes of Health Stroke Scale score, using mixed-effects logistic regression models. This study is registered with PROSPERO, number CRD42019128036. Findings: We identified three trials that met eligibility criteria: EXTEND, ECASS4-EXTEND, and EPITHET. Of the 414 patients included in the three trials, 213 (51%) were assigned to receive alteplase and 201 (49%) were assigned to receive placebo. Overall, 211 patients in the alteplase group and 199 patients in the placebo group had mRS assessment data at 3 months and thus were included in the analysis of the primary outcome. 76 (36%) of 211 patients in the alteplase group and 58 (29%) of 199 patients in the placebo group had achieved excellent functional outcome at 3 months (adjusted odds ratio [OR] 1·86, 95% CI 1·15–2·99, p=0·011). Symptomatic intracerebral haemorrhage was more common in the alteplase group than the placebo group (ten [5%] of 213 patients vs one [<1%] of 201 patients in the placebo group; adjusted OR 9·7, 95% CI 1·23–76·55, p=0·031). 29 (14%) of 213 patients in the alteplase group and 18 (9%) of 201 patients in the placebo group died (adjusted OR 1·55, 0·81–2·96, p=0·66). Interpretation: Patients with ischaemic stroke 4·5–9 h from stroke onset or wake-up stroke with salvageable brain tissue who were treated with alteplase achieved better functional outcomes than did patients given placebo. The rate of symptomatic intracerebral haemorrhage was higher with alteplase, but this increase did not negate the overall net benefit of thrombolysis