Appeals to evidence for the resolution of wicked problems: the origins and mechanisms of evidentiary bias

Wicked policy problems are often said to be characterized by their ‘intractability’, whereby appeals to evidence are unable to provide policy resolution. Advocates for ‘Evidence Based Policy’ (EBP) often lament these situations as representing the misuse of evidence for strategic ends, while critical policy studies authors counter that policy decisions are fundamentally about competing values, with the (blind) embrace of technical evidence depoliticizing political decisions. This paper aims to help resolve these conflicts and, in doing so, consider how to address this particular feature of problem wickedness. Specifically the paper delineates two forms of evidentiary bias that drive intractability, each of which is reflected by contrasting positions in the EBP debates: ‘technical bias’ - referring to invalid uses of evidence; and ‘issue bias’ - referring to how pieces of evidence direct policy agendas to particular concerns. Drawing on the fields of policy studies and cognitive psychology, the paper explores the ways in which competing interests and values manifest in these forms of bias, and shape evidence utilization through different mechanisms. The paper presents a conceptual framework reflecting on how the nature of policy problems in terms of their complexity, contestation, and polarization can help identify the potential origins and mechanisms of evidentiary bias leading to intractability in some wicked policy debates. The discussion reflects on whether being better informed about such mechanisms permit future work that may lead to strategies to mitigate or overcome such intractability in the future

Case Report – Successful Thrombectomy After Critical Resuscitation Following a Cardiac Arrest

Sparse evidence exists to support a delayed attempt at thrombectomy after a periprocedural cardiac arrest or acute medical decompensation. This case highlights the presentation of a 23‐year‐old woman with dilated cardiomyopathy, who initially presented with a left middle cerebral artery stroke syndrome, but who had a cardiac arrest in the angiogram suite prior to the procedure starting. After aggressive resuscitation in the critical care unit, repeat imaging showed a persistent perfusion deficit in the left middle cerebral artery territory and she successfully underwent a thrombectomy. The case highlights that critical care efforts, even after a severe initial presentation, and significant resuscitative efforts in the intensive care unit setting, can still lead to a successful thrombectomy, and that eligibility for thrombectomy can be reassessed as the patient stabilizes

Transradial cerebral angiography: techniques and outcomes

BackgroundDespite several retrospective studies analyzing the safety and efficacy of transradial access (TRA) versus transfemoral access (TFA) for cerebral angiography, this transition for neurointerventional procedures has been gradual. Nonetheless, based on our positive initial institutional experience with TRA for mechanical thrombectomy in acute ischemic stroke patients, we have started transitioning more of our cerebral angiography cases to TRA. Here we present our single institution experience.MethodsWe performed a retrospective review of patients receiving TRA cerebral angiography at our institution between January 2016 and February 2017. We present our experience transitioning from TFA to TRA, including our criteria for patient selection, technical nuances, patient experience, complications, and operator learning curve.ResultsWe included 148 angiograms performed in 141 people by one of four operators. No major complications were observed, and the technical success of the procedures was consistent with those of TFA. Marked improvement in operator efficiency was achieved in a short number of cases during this transition when looking at operator proficiency as a function of angiograms performed and days of exposure to TRA (4.3 vs 3.6 min/vessel, P<0.05).ConclusionsSafety and efficiency can be preserved while transitioning to TRA. While further investigation is necessary to support transition to TRA, these findings should call for a re-evaluation of the role of TRA in catheter cerebral angiography

Abstract 109: Endonasal Endoscopic Approach Associated Cerebral Vasospasm and Management: A Case Report

Introduction Endoscopic endonasal approach(EEA) techniques have been increasingly utilized and have been associated with development of cerebrospinal fluid(CSF) leak, meningitis, diabetes insipidus post‐operatively. Cerebral vasospasm following EEA has rarely been described. Here, we describe the clinical course and management of a patient who underwent EEA for encephalocele repair whose course was complicated by postoperative subarachnoid hemorrhage(SAH) and cerebral vasospasm. Methods n/a Results Case Presentation: 40 year old female with past medical history significant for cerebral venous sinus stent on aspirin, CSF rhinorrhea secondary to right nasal encephalocele s/p endoscopic transnasal transethmoidal repair with nasoseptal flap reconstruction and lumbar drain placement eleven days prior presented with speech difficulties and right sided weakness. On exam, patient was noted to have mild right hemiparesis and expressive aphasia. MRI brain showed subacute infarcts in left greater than right frontal lobes, corpus collosum and right anterior perforated substance. MRA head demonstrated multifocal arterial stenosis. In light of postoperative CT head showing SAH in the basilar, perimesencephalic, prepontine cisterns, interhemispheric fissure and right frontal sulci as well as intraventricular hemorrhage in fourth ventricle, her presentation was thought to be secondary to cerebral vasospasm in the setting of postoperative SAH. She was treated with intravenous hydration, permissive hypertension with head of bed in flat position and transferred for further evaluation. On arrival, she continued have mild right hemiparesis and aphasia. Repeat CTA head/neck and CT perfusion showed severe stenosis of bilateral M1 segments and left greater than right A1 segments as well as ischemic penumbra in left ACA/MCA watershed territory. Diagnostic cerebral angiogram showed bilateral severe A1 stenosis and mild to moderate bilateral M1 and supraclinoid ICA stenosis which improved with intra‐arterial verapamil. She was started on nimodipine. Systolic blood pressure was augmented with vasopressors for goal of 150‐180mmHg. Daily TCDs were followed. She developed worsening right leg weakness following day, thus she was taken for repeat diagnostic cerebral angiogram during which time she was re‐administered intra‐arterial verapamil with improvement in vasospasm. After the second treatment, she had improvement in speech and motor strength. Systolic blood pressure goal was gradually normalized. She was noted to have incidental left internal jugular (IJ) vein thrombosis for which anticoagulation was held in the setting of recent neurosurgical procedure and SAH. Workup for vasculitis and hypercoagulability was unrevealing. Lumbar puncture demonstrated 13 WBC/cu mm with lymphocytic predominance(90%), 23 RBC/cu mm, glucose 89mg/dl, protein 30mg/dl. CSF cultures were negative. Pleocytosis in CSF was attributed to recent neurosurgical procedure. Her neurological exam improved to baseline on hospital day(HD) 9.On HD12, she was found to have left common femoral deep venous thrombus in addition to the left IJ thrombus. Anticoagulation with low dose heparin infusion was started which was transitioned to apixaban on discharge. She was discharged home on HD20. Conclusion We report a case of EEA associated with severe multifocal cerebral vasospasm secondary to postoperative SAH that was successfully treated with induced hypertension, oral nimodipine and intra‐arterial verapamil as an adjunct therapy with an excellent outcome

Utility of intraoperative diagnostic C-arm angiography for management of high grade subarachnoid hemorrhage

The accurate and efficient localization of underlying vascular lesions is crucial for prompt and definitive treatment of subarachnoid hemorrhage (SAH). To demonstrate the utility and feasibility of intraoperative C-arm angiography in cerebrovascular emergencies, we report five cases of high grade SAH and/or intracerebral hemorrhage (ICH) where intraoperative diagnostic C-arm angiography was safely and effectively utilized. Initial evaluations of all patients included a non-contrast head CT scan, which was followed by urgent decompressive hemicraniectomy as a life-saving measure in the presence of markedly elevated intracranial pressure. Further diagnostic evaluations were performed intraoperatively using a multi-purpose C-arm angiography system. The C-arm angiography findings greatly aided the intraoperative planning and led to definitive treatments in four cases of SAH by elucidating the underlying neurovascular lesions. With this treatment strategy, two of the patients made moderately good recoveries from their SAH and/or ICH with a Glasgow outcome score (GOS) of 4. Three of the patients expired despite maximal therapy mostly due to unfavorable presenting grade. These results suggest that C-arm angiography is a reasonable diagnostic and surgical planning tool for selected patients with high grade diffuse SAH who require immediate decompression