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

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

Pipeline Embolization for Salvage Treatment of Previously Stented Residual and Recurrent Cerebral Aneurysms

IntroductionThis study assessed the safety and effectiveness of the Pipeline embolization device (PED) for persistent and recurrent aneurysms previously treated with either a vascular reconstruction device (VRD) or a flow diverter (FD).MethodsA prospective, IRB-approved database was analyzed for patients treated with PED for aneurysms previously treated with a stent.ResultsTwenty procedures were performed on 18 patients, 11 with prior FD, 7 with VRD, and 2 previously treated with both. Overall, 15 aneurysms were saccular (75%), and size was 13.5 ± 7.6 mm. Location was internal carotid artery (ICA) in 14 cases (70%) and posterior circulation in 6 cases (30%). Average prior treatments were 1.7. Previously FD cases were re-treated at an average of 18.1 months from most recent treatment. Each case used 1 device, 82% with distal coverage and 82% with proximal coverage of prior stent. Balloon remodeling was performed in 3 cases (27%) and no in-stent thrombosis was observed. Previously VRD stent-coiled cases were re-treated at an average of 87.5 months. These cases used on average 1.9 devices, 89% with distal and 100% proximal coverage. Adjunctive coiling was performed in 1 case (11%), balloon remodeling in 5 cases (56%), and 2 cases (28%) developed thrombosis that resolved with abciximab. Re-VRD cases were longer (59.1 vs. 33.7 min, p = 0.02) than re-FD. Angiographic follow-up was available for 16 cases (80%). In re-FD, occlusion was complete in 56% and partial progressive in 33% at 17.1 months digital subtraction angiography. In re-VRD, occlusion was complete in 57% and partial progressive in 27% at 8.1 months. Two complications occurred (10%), including one asymptomatic cervical ICA occlusion and one stent occlusion with associated mortality (5%). Clinical follow-up was 17.8 months on average (range 0.5-51.9).ConclusionsSalvage flow diversion for previously stented aneurysms is technically challenging but offers good prospects of aneurysm obliteration with acceptable complication rates