Recurrence of cervical artery dissection: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Cervical artery dissection (CAD) involving the carotid or vertebral arteries is an important cause of stroke in younger patients. The purpose of this systematic review is to assess the risk of recurrent CAD.

METHODS

A systematic review and meta-analysis was conducted on studies in which patients experienced radiographically confirmed dissections involving an extracranial segment of the carotid or vertebral artery and in whom CAD recurrence rates were reported.

RESULTS

Data were extracted from 29 eligible studies (n = 5898 patients). Analysis of outcomes was performed by pooling incidence rates with random effects models weighting by inverse of variance. The incidence of recurrent CAD was 4% overall (95% confidence interval (CI) = 3-7%), 2% at 1 month (95% CI = 1-5%), and 7% at 1 year in studies with sufficient follow-up (95% CI = 4-13%). The incidence of recurrence associated with ischemic events was 2% (95% CI = 1-3%).

CONCLUSIONS

We found low rates of recurrent CAD and even lower rates of recurrence associated with ischemia. Further patient-level data and clinical subgroup analyses would improve the ability to provide patient-level risk stratification.

Network meta-analysis can inform the ethical evaluation of trials that randomise away from standard of care: The case of symptomatic carotid stenosis

OBJECTIVE

Little guidance exists on the conduct of randomised clinical trials (RCT) that seek to randomise patients away from standard of care. We sought to test the technique of network meta-analysis (NMA) to ascertain best available evidence for the purposes of informing the ethical evaluation of RCTs under these circumstances. We used the example of RCTs for patients with symptomatic, moderate to severe carotid stenosis that seek to compare surgical intervention plus medical therapy (standard of care) versus medical therapy (less than standard of care).

STUDY DESIGN AND SETTING

Network meta-analysis of RCTs of adults with symptomatic carotid artery stenosis of 50%-99% who were treated with carotid endarterectomy (CEA), carotid artery stenting (CAS), or medical therapy (MT). The primary outcome was any stroke or death until end of follow-up, and secondary outcome was 30-day risk of ipsilateral stroke/death.

RESULTS

We analysed eight studies, with 7187 subjects with symptomatic moderate/severe stenosis (50%-99%). CEA was more efficacious than MT (HR = 0.82, 95% credible intervals [95% CrI] = 0.73-0.92) and CAS (HR 0.73, 95% CrI = 0.62-0.85) for the prevention of any stroke/death. At 30 days, the odds of experiencing an ipsilateral stroke/death were significantly lower in the CEA group compared to both MT (OR = 0.58, 95% CrI = 0.47-0.72) and CAS (OR = 0.68, 95% CrI = 0.55-0.83).

CONCLUSION

Our results support the feasibility of using NMA to assess best available evidence to inform the ethical evaluation of RCTs seeking to randomise patients away from standard of care. Our results suggest that a strong argument is required to ethically justify the conduct of RCTs that seek to randomise patients away from standard of care in the setting of symptomatic moderate to severe carotid stenosis.

The prevalence of non-contrast CT imaging abnormalities in reversible cerebral vasoconstriction syndrome: A systematic review and meta-analysis

BACKGROUND

Reversible cerebral vasoconstriction syndrome (RCVS) is a syndrome of recurrent thunderclap headaches and reversible vasoconstriction of the cerebral arteries on neuroimaging within 3 months of onset. Initial non-contrast computed tomography (CT) can reveal abnormalities such as ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage (SAH) can be present in patients with RCVS and may delay diagnosis.

AIMS

We conducted a systematic review and meta-analysis in accordance with the PRISMA guidelines. We aimed to estimate the prevalence of imaging abnormalities on initial non-contrast CT head in adult patients with RCVS.

DATA SOURCES & ELIGIBILITY CRITERIA

We searched electronic databases including MEDLINE, EMBASE, and the Cochrane Register of Clinical Trials from inception to August 2, 2022. Eligible studies included articles reporting the prevalence of non-contrast CT abnormalities on initial neuroimaging in patients with RCVS, aged 18 and older. Case series, observational studies and clinical trials were included. Data was extracted directly from included papers using a standardized data charting form.

RESULTS

The search yielded 722 titles with duplicates removed. Twenty studies that included 379 patients with RCVS met inclusion criteria. We classified non-contrast CT abnormalities as either ischemic stroke, ICH, or SAH. We pooled prevalence data using a random effects model with the inverse-variance weighted method. The most common imaging finding was SAH with a pooled prevalence of 24% (95% CI:17%-33%), followed by ICH at 14% (95% CI:8%-22%), and ischemic stroke at 10% (95% CI:7%-14%). The pooled prevalence of any of these imaging abnormalities on initial non-contrast CT was 31% (95% CI:23%-40%). Risk of bias was moderate to very-high-risk for case-series and low-risk for observational studies.

CONCLUSION

Our review demonstrates that one-third of patients with RCVS will have an abnormality on initial non-contrast CT head, including either an ischemic stroke, ICH, or SAH. These findings highlight the diagnostic challenges of RCVS imaging and contribute to our understanding of this disease.

Advance Consent in Acute Stroke Trials: Survey of Canadian Research Ethics Board Chairs

Advance consent could allow individuals at high risk of stroke to provide consent before they might become eligible for enrollment in acute stroke trials. This survey explores the acceptability of this novel technique to Canadian Research Ethics Board (REB) chairs that review acute stroke trials. Responses from 15 REB chairs showed that majority of respondents expressed comfort approving studies that adopt advance consent. There was no clear preference for advance consent over deferral of consent, although respondents expressed significant concern with broad rather than trial-specific advance consent. These findings shed light on the acceptability of advance consent to Canadian ethics regulators.

Advance Consent in Acute Stroke Trials: Survey of Canadian Stroke Physicians

Advance consent presents a potential solution to the challenge of obtaining informed consent for participation in acute stroke trials. Clinicians in stroke prevention clinics are uniquely positioned to identify and seek consent from potential stroke trial participants. To assess the acceptability of advance consent to Canadian stroke clinic physicians, we performed an online survey. We obtained 58 respondents (response rate 35%): the vast majority (82%) expressed comfort with obtaining advance consent and 92% felt that doing so would not be a significant disruption to clinic workflow. These results support further study of advance consent for acute stroke trials.

Ethical evaluation in acute stroke decision-making

RATIONALE

The evidentiary standards and epistemic models of clinical care, especially those of evidence-based medicine, are dissimilar to those used in philosophy and examination of how the two systems intersect may help clinicians make more informed treatment decisions.

AIMS AND OBJECTIVES

This paper examines the use of ethical frameworks in routine clinical decision-making, using the example of acute stroke treatment decisions to demonstrate that ethical evaluation is integral to clinical practice.

METHOD

Utilising acute stroke care as a lens through which to examine the phenomenon of ethical evaluation in medical practice, we offer a philosophical analysis of the presence of ethical evaluation in medicine.

RESULTS AND CONCLUSION

We find that the medical establishment should embrace ethical evaluation as intrinsic to medical practice and that medical training and treatment guidelines should reflect this reality. Patients deserve clarity and transparency about how physicians make determinations about their treatment, and physicians should be prepared to offer explanations for those decisions.

Resource allocation decisions under pandemic conditions: A cross-sectional survey of Ontario physicians

The COVID-19 pandemic has forced physicians to confront difficult choices regarding the allocation of scarce resources, such as ventilators and critical care beds. Developing policies to guide the allocation of such resources has proven challenging. An understanding of physicians' attitudes and beliefs surrounding resource allocation could help inform policymaking. As a replication and extension of a survey of Ottawa physicians conducted in 2020, we surveyed physicians across Ontario, Canada in April 2021. This survey examined physicians' sense of preparedness to allocate critical care resources during the pandemic, attitudes concerning resource allocation policy, and approaches to resource allocation decision-making. Of the 253 responses included for analysis, the majority (67%) of respondents indicated feeling "somewhat" or "a little prepared" to make resource allocation decisions, while 20% indicated feeling "not at all prepared." Most respondents (86%) agreed that a policy to guide resource allocation in the event of scarcity should exist. Physicians overwhelmingly agreed that important factors to consider when making resource allocation decisions included the patient likelihood of survival, frailty index, comorbidities, and cognitive status. Responses from the province-wide survey conducted in 2021 resemble the results of an analogous survey of Ottawa physicians conducted in 2020. Physicians generally felt underprepared to make resource allocation decisions and agreed that official policies should guide such decisions. Identification of factors relevant to resource allocation was remarkably consistent across this sample and that taken in 2020.

Spontaneous Recanalization of Internal Carotid Artery Occlusion: A Case Report

INTRODUCTION

Spontaneous recanalization of an occluded internal carotid artery (ICA) is thought to be unlikely. However, there has been a growing number of reports describing this phenomenon. Despite this, the frequency, time course, and mechanism of spontaneous recanalization remain unknown. In this paper, we describe a patient with a symptomatic recanalization of an occluded left ICA.

CASE REPORT

A 70-year-old woman presented with transient speech arrest and right upper extremity weakness related to an occluded ICA. After 3 days, her weakness and aphasia reappeared and worsened transiently. A repeat computed tomography angiography revealed recanalization of the occluded ICA, as well as new ischemic changes in the previously hypoperfused left insular region. This finding changed the management from medical management to revascularization with a stent, after which the patient was discharged home with acetylsalicylic acid and clopidogrel.

CONCLUSIONS

Although previously thought to be a rare occurrence, spontaneous recanalization is not uncommon. Further research into this phenomenon as proper identification and characterization of this phenomenon can influence follow-up and management.

What do we talk about when we talk about "equipoise"? Stakeholder interviews assessing the use of equipoise in clinical research ethics

INTRODUCTION

Equipoise, generally defined as uncertainty about the relative effects of the treatments being compared in a trial, is frequently referenced as an ethical standard for the conduct of randomized clinical trials. However, it seems to be defined in several different ways and may be used differently by different individuals. We explored how clinical researchers, chairs of research ethics boards, and philosophers of science define and reason with this term.

METHODS

We completed semi-structured interviews about clinical trial ethics with 15 clinical researchers, 15 research ethics board chairs, and 15 philosophers of science/bioethicists. Each participant was asked a standardized set of 10 questions, 4 of which were specifically about equipoise. All interviews were conducted telephonically and transcribed. Responses were grouped and analysed via a modified grounded theory method.

RESULTS

Forty-three respondents defined equipoise in 7 logically distinct ways, and 2 respondents could not explicitly define it. The most common definition, offered by 14 respondents (31%), defined "equipoise" as a disagreement at the level of a community of physicians. There was significant variability in definitions offered between and within groups. When asked how they would "operationalize" equipoise - i.e. check or test for its presence - respondents provided 7 alternatives, the most common being in relation to a literature review (15/45, 33%). The vast majority of respondents (35/45, 78%) felt the concept was helpful, though many acknowledged that the lack of a clear definition or operationalization was problematic.

CONCLUSION

There is significant variation in definitions of equipoise offered by respondents, suggesting that parties within groups and between groups may be referring to different concepts when they reference "equipoise". This non-uniformity may impact fairness and transparency and opens the door to potential ethical problems in the evaluation of clinical trials - for instance, a patient may understand equipoise very differently than the researchers enrolling her in a trial, which could cause her agreement to participate to be based upon false premises.

Prevalence of spontaneous recanalisation of complete internal carotid occlusion: protocol for a systematic scoping review

INTRODUCTION

Although previously thought to be a rare occurrence, spontaneous recanalisation is not uncommon, with a growing number of reports describing this phenomenon. However, the frequency, time course and mechanism of spontaneous recanalisation remain unknown. A better characterisation of these events is essential to ensuring adequate identification and proper future trial design for treatment.

OBJECTIVE

To describe the current body of literature around spontaneous recanalisation following internal carotid occlusion.

METHODS AND ANALYSIS

With the assistance of an information specialist, we will search MEDLINE, Embase, Cochrane Central Register for Controlled Trials and Web of Science for studies of adults with spontaneous recanalisation or transient occlusion of the internal carotid artery. Two reviewers will independently collect data on included studies pertaining to publication data, study population information, timepoints of initial presentation, recanalisation and subsequent follow-up.

ETHICS AND DISSEMINATION

Primary data will not be collected; therefore, formal ethics is not required. The findings of this study will be disseminated through peer-reviewed publications and presentations at academic conferences.

Advance consent for participation in randomised controlled trials for emergency conditions: a scoping review

OBJECTIVE

Advance consent is a recognised method of obtaining informed consent for participation in research, whereby a potential participant provides consent for future involvement in a study contingent on qualifying for the study's inclusion criteria on a later date. The goal of this study is to map the existing literature on the use of advance consent for enrolment in randomised controlled trials (RCTs) for emergency conditions.

DESIGN

Scoping review designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews guidelines.

DATA SOURCES

We searched electronic databases including MEDLINE, Embase, Web of Science and the Cochrane Register of Clinical Trials from inception to 10 February 2020.

ELIGIBILITY CRITERIA

Eligible studies included articles that discussed or employed the use of advance consent for enrolment in RCTs related to emergency conditions. There were no restrictions on the type of eligible study. Data were extracted directly from included papers using a standardised data charting form. We produced a narrative review including article type and authors' dispositions towards advance consent.

RESULTS

Our search yielded 1039 titles with duplicates removed. Six articles met inclusion criteria. Three articles discussed the theoretical use of research advance directives in emergency conditions; one article evaluated stakeholders' perceptions of advance consent; and one article described a method for patients to document their preferences for participation in future research. Only one study employed advance consent to enrol participants into a clinical trial for an emergency condition.

CONCLUSION

Our review demonstrates that there has been minimal exploration of advance consent for enrolment in RCTs for emergency conditions. Future studies could aim to assess the acceptability of advance consent to participants, along with the feasibility of enrolling research participants using this method of consent.

PROTOCOL

The protocol for this scoping review was published a priori.

Protocol for Deferral of Consent in Acute Stroke Trials

The challenges of conducting hyperacute stroke research and obtaining informed consent have been increasingly recognized within the stroke research community in recent years. Deferral of consent, in which a patient is enrolled in a trial and then provides consent at some point thereafter, is increasingly used to enroll patients into hyperacute stroke trials in Canada and Europe, although it is not permitted in the United States. Deferral of consent offers several potential advantages-quicker door-to-randomization, increased enrolment, decreased selection bias-but these must be balanced against the risk of enrolling patients against their wishes. We seek to minimize the attendant risks of deferral of consent by offering practical guidance regarding how to conduct acute stroke trials using deferral of consent. Building on existing guidelines and recent experiences with deferral of consent in acute stroke trials, we have developed a protocol for the use of deferral of consent that aims to maximize patient involvement while minimizing ethical and scientific risks.

Use of evidence in acute stroke decision-making: Implications for evidence-based medicine

RATIONALE, AIMS AND OBJECTIVES

Evidence-Based Medicine proposes a prescriptive model of physician decision-making in which 'best evidence' is used to guide best practice. And yet, proponents of EBM acknowledge that EBM fails to offer a systematic theory of physician decision-making.

METHODS

In this paper, we explore how physicians from the neurology and emergency medicine communities have responded to an evolving body of evidence surrounding the acute treatment of patients with ischemic stroke. Through analysis of this case study, we argue that EBM's vision of evidence-based medical decision-making fails to appreciate a process that we have termed epistemic evaluation.

RESULTS AND CONCLUSIONS

Physicians are required to interpret and apply any knowledge-even what EBM would term 'best evidence'-in light of their own knowledge, background and experience. This is consequential for EBM as understanding what physicians do and why they do it would appear to be essential to achieving optimal practice in accordance with best evidence.

“Everything has been tried and his heart can’t recover…”: A Descriptive Review of “Do Everything!” in the Archive of Ontario Consent and Capacity Board

Background

In end-of-life situations, the phrase “do everything” is sometimes invoked by physicians, patients, or substitute decision-makers (SDM), though its meaning is ambiguous. We examined instances of the phrase “do everything” in the archive of the Ontario Consent and Capacity Board (CCB) in Canada, a tribunal with judicial authority to adjudicate physician–patient conflicts in order to explore its potential meanings.

Methods

We systematically searched the CCB’s online public archive from its inception to 2018 for any references to “do everything” in the context of critical care medicine and end-of-life care. Two independent assessors reviewed decisions, collected characteristics, and identified key themes.

Results

Of 598 cases in the archive, 41 referred to “do everything” in end-of-life situations. The phrase was overwhelmingly invoked by SDMs (38/41, 93%), typically to advocate for life-prolonging measures that contradicted physician advice. Physicians generally related “doing everything” to describe the interventions they had already performed (3/41, 7%), using it to recommend focusing on patients’ quality of life. SDMs were generally reluctant to accept death, whereas physicians found prolonging life at all costs to be morally distressing. The CCB did not interpret appeals to “do everything” legally but followed existing laws by deferring to patients’ prior wishes whenever known, or to concepts of “best interests” when not. The CCB generally recommended against life-prolonging measures in these cases (26/41, 63%), focusing on patients’ “well-being” and “best interests.”

Conclusions

In this unique sample of cases involving conflict surrounding resuscitation and end-of-life care, references to “do everything” highlighted conflicts over quantity versus quality of life. These appeals were associated with signs of cognitive distress on the behalf of SDMs who were facing the prospect of a patient’s death, whereas physicians identified moral distress related to the prolongation of patients’ suffering through their use of life-sustaining interventions. This divergence in perspectives on death versus suffering was consistently the locus of conflict. These findings support the importance of tools such as the Serious Illness Conversation Guide that can be used by physicians to direct conversations on the patients’ goals, wishes, trade-offs, and to recommend a treatment plan that may include palliative care.

Trial Registration

Not applicable.

Ethical Justification for Deferral of Consent in the AcT Trial for Acute Ischemic Stroke

The AcT trial (Alteplase Compared to Tenecteplase) compares alteplase or tenecteplase for patients with acute ischemic stroke. All eligible patients are enrolled by deferral of consent. Although the use of deferral of consent in the AcT trial meets the requirements of Canadian policy, we sought to provide a more explicit and rigorous approach to the justification of deferral of consent organized around 3 questions. Ultimately, the approach we outline here could become the foundation for a general justification for deferral of consent.

Goods, causes and intentions: problems with applying the doctrine of double effect to palliative sedation

BACKGROUND

Palliative sedation and analgesia are employed in patients with refractory and intractable symptoms at the end of life to reduce their suffering by lowering their level of consciousness. The doctrine of double effect, a philosophical principle that justifies doing a "good action" with a potentially "bad effect," is frequently employed to provide an ethical justification for this practice.

MAIN TEXT

We argue that palliative sedation and analgesia do not fulfill the conditions required to apply the doctrine of double effect, and therefore its use in this domain is inappropriate. Furthermore, we argue that the frequent application of the doctrine of double effect to palliative sedation and analgesia reflects physicians' discomfort with the complex moral, intentional, and causal aspects of end-of-life care.

CONCLUSIONS

We are concerned that this misapplication of the doctrine of double effect can consequently impair physicians' ethical reasoning and relationships with patients at the end of life.

How outcomes are measured after spontaneous intracerebral hemorrhage: A systematic scoping review

Background and purpose

Recovery after intracerebral haemorrhage (ICH) is often slower than ischemic stroke. Despite this, ICH research often quantifies recovery using the same outcome measures obtained at the same timepoints as ischemic stroke. The primary objective of this scoping review is to map the existing literature to determine when and how outcomes are being measured in prospective studies of recovery after ICH.

Methods

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Web of Science from inception to November 2019, for prospective studies that included patients with ICH. Two investigators independently screened the studies and extracted data around timing and type of outcome assessment.

Results

Among the 9761 manuscripts reviewed, 395 met inclusion criteria, of which 276 were observational studies and 129 were interventional studies that enrolled 66274 patients. Mortality was assessed in 93% of studies. Functional outcomes were assessed in 85% of studies. The most frequently used functional assessment tool was the modified Rankin Scale (mRS) (60%), followed by the National Institute of Health Stroke Severity Scale (22%) and Barthel Index (21%). The most frequent timepoint at which mortality was assessed was 90 days (41%), followed by 180 days (18%) and 365 days (12%), with 2% beyond 1 year. The most frequent timepoint used for assessing mRS was 90 days (62%), followed by 180 days (21%) and 365 days (17%).

Conclusion

While most prospective ICH studies report mortality and functional outcomes only at 90 days, a significant proportion do so at 1 year and beyond. Our results support the feasibility of collecting long-term outcome data to optimally assess recovery in ICH.

Deferral of Consent: Recent Lessons From Canadian Acute Stroke Trials

[Figure: see text].

Identifying sex-specific differences in the carotid revascularisation literature: findings from a scoping review

Objective

No systematic review of the literature has dedicated itself to looking at the management of symptomatic carotid stenosis in female patients. In this scoping review, we aimed to identify all randomised controlled trials (RCTs) that reported sex-specific outcomes for patients who underwent carotid revascularisation, and determine whether sufficient information is reported within these studies to assess short-term and long-term outcomes in female patients.

Design, setting and participants

We systematically searched Medline, Embase, Pubmed and Cochrane libraries for RCTs published between 1991 and 2020 that included female patients and compared either endarterectomy with stenting, or any revascularisation (endarterectomy or stenting) with medical therapy in patients with symptomatic high-grade (>50%) carotid stenosis.

Results

From 1537 references examined, 27 eligible studies were identified. Sex-specific outcomes were reported in 13 studies. Baseline patient characteristics of enrolled female patients were reported in 2 of those 13 studies. Common outcomes reported included stroke and death, however, there was significant heterogeneity in the reporting of both periprocedural and long-term outcomes. Sex-specific differences relating to the degree of stenosis and time from index event to treatment are largely limited to studies comparing endarterectomy to medical therapy. Adverse events were not reported by sex.

Conclusions

Only half of the previously published RCTs and systematic reviews report sex-specific outcomes. Detailed analyses on the results of carotid artery intervention for female patients with symptomatic stenosis are limited.

Association between insulin resistance and post-ischaemic stroke outcome in patients without diabetes: protocol for a systematic review and meta-analysis

INTRODUCTION

Insulin resistance is an independent risk factor for atherosclerosis, coronary artery disease and ischaemic stroke. Currently, insulin resistance is not usually included in post-stroke risk stratification. This systematic review and meta-analysis intends to determine if available scientific knowledge supports an association between insulin resistance and post-stroke outcomes in patients without diabetes.

METHODS AND ANALYSIS

The authors will conduct a literature search in Medline, Embase, Web of Science and Cochrane Central. The review will include studies that assess the association between elevated insulin homeostasis model of insulin resistance (HOMA-IR) and post-stroke outcome (functional outcome and recurrent stroke). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines will be used. The primary outcome will be post-stroke functional outcome (Modified Rankin Scale), and the secondary outcome will be recurrent ischaemic stroke. Comparison of outcome will be made between highest and lowest HOMA-IR range (as defined in each article included in this systematic review). Risk of bias will be assessed qualitatively. Meta-analysis will be performed if sufficient homogeneity exists between studies. Heterogeneity of outcomes will be assessed by I².

ETHICS AND DISSEMINATION

No human or animal subjects or samples were/will be used. The results will be published in a peer-reviewed journal, and will be disseminated at local and international neurology conferences.

PROSPERO REGISTRATION NUMBER

CRD42020173608.

Abstract P566: Identifying Sex-Specific Differences in the Carotid Revascularization Literature: Findings From a Scoping Review

Background and Purpose: No systematic review of the literature has dedicated itself to looking at the management of symptomatic carotid stenosis in women. In this scoping review, we aimed to identify all randomized controlled trials (RCTs) that reported sex-specific outcomes for patients who underwent carotid revascularization, and determine whether sufficient information is reported within these studies to assess women’s short and long-term outcomes.

Methods: We systematically searched Medline, Embase, Pubmed, and Cochrane libraries for RCTs published between 1991 and 2020 that included women and compared either endarterectomy with stenting, or any revascularization (endarterectomy or stenting) with medical therapy in patients with symptomatic high grade (greater than 50%) carotid stenosis.

Results: From 1,537 references examined, 27 eligible studies were identified. Sex-specific outcomes were reported in 13 studies. Baseline patient characteristics of enrolled women were reported in 2 of those 13 studies. Common outcomes reported included stroke and death, however there was significant heterogeneity in the reporting of both periprocedural and long-term outcomes. Sex-specific differences relating to the degree of stenosis and time from index event to treatment were limited to studies comparing endarterectomy to medical therapy. Adverse events were not reported by sex.

Conclusions: Half of the previously published RCTs and systematic reviews report sex-specific outcomes. Detailed analysis on the benefits of carotid artery intervention for women with symptomatic stenosis is limited . Further analysis with individual patient data and a network meta-analysis is the necessary next step to better assess the treatment effects of carotid management in women.

Rationalisations for women-only randomised controlled trials in conditions that affect both sexes: a scoping review protocol

INTRODUCTION

Women have historically been under-represented in randomised controlled trials (RCTs), including many landmark RCTs that established standards of care. In light of this fact, some modern researchers are calling for replication of earlier landmark trials with women only. This approach is ethically concerning, in that it would require some enrolled women to be deprived of treatments that are currently considered standard of care.

OBJECTIVE

In an attempt to better understand the justification of a women-only approach to designing clinical trials, this study looks to systematically categorise the number of women-only RCTs for conditions that affect both men and women and the reasons given within the medical and philosophical literatures to perform them.

METHODOLOGY

This scoping review of the literature will search, screen and select articles based on predetermined inclusion/exclusion criteria, after which a grounded theory approach will be used to synthesise the data. It is expected that there will be a variety of reasons given for why a women-only trial may be justified. Electronic databases that will be searched include MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Clinical Trials Register, Web of Science Proceedings, ClinicalTrials.gov, Philosopher's Index, Phil Papers, JSTOR, Periodicals Archive Online, Project MUSE and the National Reference Centre for Bioethics.

SIGNIFICANCE

The scope of this study is to determine published rationales used to justify women-only randomised trials, both in the case of new trials and in the repetition of landmark trials.

ETHICS AND DISSEMINATION

Research ethics board approval is not required for this study as there is no participant involvement. Results will be published as a stand-alone manuscript and will inform a larger project related to the ethics of a women-only RCT of carotid intervention for women with symptomatic high-grade carotid stenosis.

Physician preparedness for resource allocation decisions under pandemic conditions: A cross-sectional survey of Canadian physicians, April 2020

BACKGROUND

Under the pandemic conditions created by the novel coronavirus of 2019 (COVID-19), physicians have faced difficult choices allocating scarce resources, including but not limited to critical care beds and ventilators. Past experiences with severe acute respiratory syndrome (SARS) and current reports suggest that making these decisions carries a heavy emotional toll for physicians around the world. We sought to explore Canadian physicians' preparedness and attitudes regarding resource allocation decisions.

METHODS

From April 3 to April 13, 2020, we conducted an 8-question online survey of physicians practicing in the region of Ottawa, Ontario, Canada, organized around 4 themes: physician preparedness for resource rationing, physician preparedness to offer palliative care, attitudes towards resource allocation policy, and approaches to resource allocation decision-making.

RESULTS

We collected 219 responses, of which 165 were used for analysis. The majority (78%) of respondents felt "somewhat" or "a little prepared" to make resource allocation decisions, and 13% felt "not at all prepared." A majority of respondents (63%) expected the provision of palliative care to be "very" or "somewhat difficult." Most respondents (83%) either strongly or somewhat agreed that there should be policy to guide resource allocation. Physicians overwhelmingly agreed on certain factors that would be important in resource allocation, including whether patients were likely to survive, and whether they had dementia and other significant comorbidities. Respondents generally did not feel confident that they would have the social support they needed at the time of making resource allocation decisions.

INTERPRETATION

This rapidly implemented survey suggests that a sample of Canadian physicians feel underprepared to make resource allocation decisions, and desire both more emotional support and clear, transparent, evidence-based policy.

Advanced consent for participation in acute care randomised control trials: protocol for a scoping review

INTRODUCTION

Informed consent is essential to clinical research, though obtaining informed consent for participation in research for emergency conditions is challenging. Adapted consent methods include consent from a substitute-decision maker, deferral of consent and waiver of consent. A novel approach is to use advanced consent, where a potential participant provides consent in the present in the event that they become eligible for enrolment into a future study. This scoping review will map and synthesise the literature on the use of advanced consent for participation and enrolment in randomised control trials for emergency conditions.

METHODS AND ANALYSIS

Guided by Arksey and O'Malley's scoping review methodology framework, we will search electronic databases (Medline, Embase, Web of Science and the Cochrane Register of Clinical Trials), the grey literature sources and reference lists of relevant studies. Eligible studies will include English language articles that discuss, examine or employ the use of advanced consent for enrolment in randomised control trials, specifically related to emergency conditions or emergency treatment. Diverse types of articles will be eligible for inclusion, including peer-reviewed qualitative and quantitative studies such as randomised control trials, observational studies, surveys, systematic reviews, as well as narrative reviews and ethics papers. Studies will be screened by two independent reviewers to determine eligibility for inclusion. Data on bibliographic information, study characteristics and methodology, and reported results, specifically author disposition, will be extracted and described using qualitative analysis.

ETHICS AND DISSEMINATION

Formal ethics review is not required as primary data will not be collected. The findings of this study will be disseminated through a peer-reviewed publication. The findings of this study will help identify knowledge gaps that may guide areas for future research and may aid in the design of future clinical trials using advanced consent.

Prevalence of non-contrast CT abnormalities in adults with reversible cerebral vasoconstriction syndrome: protocol for a systematic review and meta-analysis

INTRODUCTION

Reversible cerebral vasoconstriction syndrome (RCVS) is characterised by severe, recurrent thunderclap headaches (TCHs) and vasoconstriction of cerebral arteries that resolve within 3 months. Abnormalities on non-contrast CT (NCCT) such as ischaemic strokes, intracerebral haemorrhage and subarachnoid haemorrhages are frequently observed on brain imaging of patients with RCVS though their prevalence varies considerably between studies. The aim of this systematic review and meta-analysis is to estimate the prevalence of NCCT abnormalities seen on neuroimaging of adult patients with RCVS.

METHODS AND ANALYSIS

We will search the Medline, Embase and the Cochrane Library databases for studies on the prevalence of NCCT abnormalities on neuroimaging of patients with RCVS. Search results will be screened for eligibility by title and abstract. Suitable studies will be fully reviewed and relevant data extracted using a data abstraction form. The studies will be assessed for methodological quality, risk of bias and heterogeneity. Prevalence estimates across studies will be pooled using a random-effects model and subgroup analysis will be performed to assess the impact of age, sex, publication year and study design on prevalence of vascular lesions. Sensitivity analysis will be used to investigate the robustness of the findings. This protocol has been devised using the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 checklist.

ETHICS AND DISSEMINATION

Formal ethics is not required as primary data will not be collected. The findings of this study will be disseminated through a peer-reviewed publication and conference presentations.

TRIAL REGISTRATION NUMBER

CRD42020190637.

Recurrence of cervical artery dissection: protocol for a systematic review

INTRODUCTION

Cervical artery dissection, including carotid and vertebral artery dissection, is an important cause of stroke in the young. Risk of developing cervical artery dissection has been associated with physical activity in various forms and has been presumed to be related to minor trauma and mechanical stretching of the cervical arteries. This systematic review will aim to synthesise data on the risk of recurrent cervical artery dissection after an initial dissection. This information may be applied to further understand the natural history of this disease, and potentially to help direct evidence-based discussions on safe return to activity after dissection.

METHODS AND ANALYSIS

A broad search of multiple electronic databases (Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science) will be conducted to identify studies published as of 13 November 2019, examining all-comers with cervical artery dissection observed over time. Studies will be screened by two independent reviewers in a two-level process to determine eligibility for inclusion. Data will be pooled from eligible articles and the main outcome of recurrent cervical artery dissection at 5 years will be determined using quantitative analysis.

ETHICS AND DISSEMINATION

Ethics approval is not necessary as no primary data are being collected. The information will be disseminated in the form of a systematic review article which will be submitted to a peer-reviewed medical journal.

PROSPERO REGISTRATION NUMBER

CRD42020166105.

Natural history of recovery after intracerebral haemorrhage: a scoping review protocol

INTRODUCTION

Clinical trials for intracerebral haemorrhage typically measure outcomes in the same way and at the same time points as trials for ischaemic stroke. However, there is growing evidence that the trajectory of recovery following intracerebral haemorrhage may differ significantly from that following ischaemic stroke. A better understanding of current approaches to outcome assessment is essential to ensure that future trials examining treatments for intracerebral haemorrhage are designed appropriately.

OBJECTIVE

To determine when and how outcomes are measured in patients with intracerebral haemorrhage.

METHODS AND ANALYSIS

With the assistance of an information specialist, we will conduct a scoping review by searching MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Web of Science for prospective studies of adults with primary intracerebral haemorrhage and documented outcomes with specified times. Two reviewers will independently collect data on included studies pertaining to publication data, study population information, timing of outcome and details of the outcome measurement tools used. The extracted data will be used to demonstrate the type and timing of outcome measures.

ETHICS AND DISSEMINATION

Primary data will not be collected therefore formal ethics is not required. The findings of this study will be disseminated through peer-reviewed publications and through presentation at academic conferences.

Benefit of carotid revascularisation for women with symptomatic carotid stenosis: protocol for a systematic review

INTRODUCTION

Carotid intervention in the form of endarterectomy or stenting is the current standard of care for the majority of patients with symptomatic high-grade carotid stenosis. However, some randomised controlled trials (RCT) have demonstrated that women benefited significantly less from intervention than men. It is unclear if this is a true phenomenon or a study sampling artefact, as women were severely under-represented in all RCTs of carotid revascularisation. A systematic review is needed to summarise the existing data and to answer the question of whether a women-only trial for symptomatic patients with ipsilateral carotid stenosis is scientifically necessary and ethically permissible.

METHODS AND ANALYSIS

We will systematically search Medline, Embase, PubMed and the Cochrane libraries for all studies with data from RCTs that included women and compared either endarterectomy with stenting or revascularisation (by means of endarterectomy or stenting) with medical therapy in patients with symptomatic carotid stenosis. Search dates will be restricted to 1991-2018. Two reviewers will conduct screening search results, study selection, data extraction and quality assessment. We will include all studies reporting outcomes of interest. Planned subgroup analysis based on revascularisation technique, degree of stenosis and timing of intervention from the index event will be conducted with enough data.

ETHICS AND DISSEMINATION

This research is exempt of ethics approval as no primary data will be collected. The results will be published in peer-reviewed journals and disseminated through national and international-level conferences and scientific meetings. The result of this comprehensive review will provide useful information on whether further RCTs are required to study a women-only population with symptomatic carotid disease.

PROSPERO REGISTRATION NUMBER

CRD42019134967.

Protocol for a systematic scoping review of reasons given to justify the performance of randomised controlled trials

INTRODUCTION

Randomised controlled trials (RCTs) are widely viewed to generate the most reliable medical knowledge. However, RCTs are not always scientifically necessary and therefore not always ethical. Unfortunately, it is not clear when an RCT is not necessary or how this should be established. This study seeks to systematically catalogue justifications offered throughout the medical and ethics literature for performing randomisation within clinical trials.

METHODS AND ANALYSIS

We will systematically search electronic databases of the medical literature including MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Clinical Trials Register, Web of Science Proceedings, ClinicalTrials.gov; databases of philosophical literature including Philosopher's Index, Phil Papers, JSTOR, Periodicals Archive Online, Project MUSE, National Reference Centre for Bioethics; the library catalogue at the University of Ottawa; bibliographies of retrieved papers; and the grey literature. We will also pursue suggestions from experts in the fields of medical ethics, philosophy and clinical trial methodology. Article screening, selection and data extraction will be performed by two independent reviewers based on prespecified inclusion/exclusion criteria. A third reviewer will be consulted to resolve any discrepancies. We will then extract the reasons given to justify randomisation using methodology established to extract data in a defensible, systematic manner. We will track the reasons given, their frequency of use and changes over time. Finally, using grounded theory, we will combine the reasons into broader themes. These themes will form the foundation of our subsequent analysis from qualitative and quantitative perspectives. This review will map existing arguments that clinicians, ethicists and philosophers use to ethically justify randomisation in clinical trials.

ETHICS AND DISSEMINATION

No research ethics board approval is necessary because we are not examining patient-level data. This protocol complies with the reported guidance for conducting systematic scoping reviews. The findings of this paper will be disseminated via presentations and academic publication. In a subsequent phase of this research, we hope to engage with stakeholders and translate any recommendations derived from our findings into operational guidelines.

tPA for Acute Ischemic Stroke and Its Controversies: A Review

Background and Purpose

Although neurologists consider intravenous tissue plasminogen activator (tPA) to be standard of care in the treatment of patients with acute ischemic stroke, its use remains contentious within the broader medical community, and particularly among emergency physicians. Why might this be? We provide a historical context to this ongoing controversy by reviewing how neurologists have conceptualized the acute stroke and its treatment, with the aim of bridging this gap.

Methods

Based on historical sources in the Mackie Family History of Neuroscience Collection at the University of Calgary, as well as online resources, we trace the evolution of the concept of the "acute stroke," which has come to mean a stroke that is potentially treatable with tPA. We frame this conceptualization in relation to historical "building blocks" in anatomy, pathology, and physiology. We then use these building blocks to explain why neurologists understand tPA to be effective and why emergency physicians often do not.

Results and Conclusions

Arguments against the use of tPA reiterate 20-year-old concerns about its efficacy and safety. We believe these persistent concerns can be framed as a lack of understanding of the "building blocks" upon which neurologists' conception of tPA is built. Our view suggests that the way forward to bridge the gap between neurology and other disciplines is not to conduct more trials but to offer a shared conceptualization of the trials already completed and of the intellectual tradition from which they emerged.

Deferral of Consent in Acute Stroke Trials

Background and Purpose—

The ESCAPE trial (The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) was a multicentre, randomized controlled trial of endovascular thrombectomy versus standard care for patients with acute ischemic stroke that allowed patients to be enrolled with deferred consent. We investigated the knowledge and opinions of these patients or their authorized third parties about the consent process.

Methods—

All patients (or their authorized third parties) enrolled with deferral of consent in ESCAPE were invited to complete a 12-question survey within the first 4 days of enrollment and again at 90 days. Questions investigated knowledge of the ESCAPE trial and opinions on deferral of consent.

Results—

Of 56 patients enrolled with deferred consent, 33 (59%) completed the initial survey, and of these, 27 (81%) completed the 90-day follow-up. Enrollment with deferred consent was not associated with a significant difference in door-to-randomization times (50.5 versus 57 minutes; P =0.29) but allowed these 56 patients to participate in the trial. Only 52% of respondents understood that patients could be randomized to thrombectomy or standard care, although most understood the other basic principles of the trial. At baseline and at 90 days, respondents disagreed or strongly disagreed with deferred consent in acute stroke trials generally (82% and 78%) and in the ESCAPE trial specifically (93% and 91%).

Conclusions—

Respondents generally disagreed with the use of deferred consent for enrollment in the ESCAPE trial and in stroke trials more generally.

Abstract WP108: What is Equipoise? Stroke Researchers and IRB Chairs Respond

Background: The concept of “equipoise” is often cited as a prerequisite to the conduct of ethical randomized clinical trials (RCTs). However, significant difficulties persist in determining when it exists around a specific clinical question. This issue has arisen around recent stroke RCTs such as ESCAPE and SWIFT DIRECT. We sought to capture how stroke research principal investigators (PIs) and institutional review board (IRB) chairs understand the concept of equipoise.

Methods: We invited stroke PIs and IRB chairs to complete a telephone interview consisting of 9 semi-structured questions surrounding equipoise and the ethics of RCTs. Interviewees provided written informed consent and results remained anonymous. The study was approved by our local IRB. Interviews were recorded and transcribed. Each interview was then analyzed for relevance to the concept of equipoise, with relevant sections coded and organized into themes.

Results: We invited 59 PIs and 84 IRB chairs, with 13 PIs and 15 IRB chairs completing the standardized interview. Respondents defined equipoise in 5 different ways, with the most common definition being uncertainty based on any of individual opinion, group opinion, evidence, lack of evidence, regional variation, or trial design. PIs sought to determine equipoise through appeals to the literature, preliminary clinical data, surveys of expert opinion, and known disagreement. IRB chairs were more dependent upon expert opinion, including that of trial PIs themselves, and were more concerned with patient protections and specifics of study design. All (100%) PIs and 77% of IRB chairs felt that the concept was helpful, though 80% of both groups also found it to be problematic.

Conclusion: Stroke PIs and IRB chairs differ in their understanding of how equipoise is defined and operationalized, which may directly impact the design and approval of current and future stroke trials.

A critical analysis of Compassion in Practice

Compassion in Practice is a policy introduced in England to develop a culture of compassionate practice among healthcare staff. There is widespread recognition and agreement of the importance of compassionate practice, and the policy offers a vision underpinned by a desirable set of values. In this article, the significance of a coherent vision is explored and is followed by discussion of the need to anchor the policy vision in values that are important to healthcare staff. The policy's approach to vision and values may generate tensions, which are also examined and discussed.

Can anonymous posters on medical forums be reidentified?

BACKGROUND

Participants in medical forums often reveal personal health information about themselves in their online postings. To feel comfortable revealing sensitive personal health information, some participants may hide their identity by posting anonymously. They can do this by using fake identities, nicknames, or pseudonyms that cannot readily be traced back to them. However, individual writing styles have unique features and it may be possible to determine the true identity of an anonymous user through author attribution analysis. Although there has been previous work on the authorship attribution problem, there has been a dearth of research on automated authorship attribution on medical forums. The focus of the paper is to demonstrate that character-based author attribution works better than word-based methods in medical forums.

OBJECTIVE

The goal was to build a system that accurately attributes authorship of messages posted on medical forums. The Authorship Attributor system uses text analysis techniques to crawl medical forums and automatically correlate messages written by the same authors. Authorship Attributor processes unstructured texts regardless of the document type, context, and content.

METHODS

The messages were labeled by nicknames of the forum participants. We evaluated the system's performance through its accuracy on 6000 messages gathered from 2 medical forums on an in vitro fertilization (IVF) support website.

RESULTS

Given 2 lists of candidate authors (30 and 50 candidates, respectively), we obtained an F score accuracy in detecting authors of 75% to 80% on messages containing 100 to 150 words on average, and 97.9% on longer messages containing at least 300 words.

CONCLUSIONS

Authorship can be successfully detected in short free-form messages posted on medical forums. This raises a concern about the meaningfulness of anonymous posting on such medical forums. Authorship attribution tools can be used to warn consumers wishing to post anonymously about the likelihood of their identity being determined.

A biosensor generated via high-throughput screening quantifies cell edge Src dynamics

Fluorescent biosensors for living cells currently require laborious optimization and a unique design for each target. They are limited by the availability of naturally occurring ligands with appropriate target specificity. Here we describe a biosensor based on an engineered fibronectin monobody scaffold that can be tailored to bind different targets via high-throughput screening. We made this Src-family kinase (SFK) biosensor by derivatizing a monobody specific for activated SFKs with a bright dye whose fluorescence increases upon target binding. We identified sites for dye attachment and changes to eliminate vesiculation in living cells, providing a generalizable scaffold for biosensor production. This approach minimizes cell perturbation because it senses endogenous, unmodified target, and because sensitivity is enhanced by direct dye excitation. Automated correlation of cell velocities and SFK activity revealed that SFKs are activated specifically during protrusion. Activity correlates with velocity, and peaks 1-2 μm from the leading edge.