London, United Kingdom 2013 Poster Session Red Cerebrovasc Dis 2013; 35 (suppl 3)1-854 445 302 Etiology of stroke and risk factors Intracranial stenosis or occlusion in an AF patient is much more likely to be in the anterior cir-culation than the posterior circulation. G.F.A. Cowley1, R.J. Perry2 University College London, London, UNITED KINGDOM1, National Hospital for Neurology & Neurosurgery, London, UNITED KINGDOM2 Introduction: Stenosis of a large intracranial vessel is recognised as an important cause of stroke. If partial or complete occlusions of intracranial vessels seen on CT angiogram mainly represent ath-eromatous stenosis then we might reasonably expect that those in the anterior and posterior circu-lations share similar risk factors. We report a retrospective study that challenges that expectation. Methods: We performed a retrospective study of patients admitted to the Hyperacute Stroke Unit at University College Hospital, London, UK in October 2011 and November 2011 who routinely re-ceive CT angiogram (CTA). We identified 86 patients with acute ischaemic stroke whose infarcts lay within the territory of an occluded or partially occluded intracranial vessel seen on CTA. We recorded the following stroke risk factors for each patient: age, gender, hypertension, hypercholes-terolaemia, diabetes mellitus, peripheral vascular disease, smoking, atrial fibrillation (AF), carotid disease and ischaemic heart disease. Results: 39 of the 72 patients with anterior circulation abnor-malities had AF (54%) compared to none of the 15 patients with posterior circulation abnormalities, a highly significant difference (chi squared = 14.73, p = 0.0001). This was the only significant dif-ference between risk factors in the two groups. Conclusion: The most plausible explanation is that most of the relevant abnormalities seen in the intracranial circulation in stroke patients with AF rep-resent cardio-embolic thrombus rather than atheroma, a conclusion that may have consequences for their endovascular management. We also conclude that AF-related emboli of sufficient size to cause a partial or complete occlusion of a large intracranial vessel are much more likely to enter the ante-rior circulation than the posterior circulation. If so, then a prolonged search for paroxysmal AF may be much harder to justify after a stroke in the posterior circulation. 303 Etiology of stroke and risk factors Acute Ischemic Strokes Missed in a Stroke Center (“Stroke Chameleons”): Causes, Risk Fac-tors and Outcome B.R. Richoz1, M.F. Faouzi2, P.M. Michel3 Centre Hospitalier Universitaire Vaudois, Lausanne, SWITZERLAND1, Centre Hospitalier Universitaire Vaudois, Lausanne, SWITZERLAND2, Centre Hospitalier Universitaire Vaudois, Lau-sanne, SWITZERLAND3 Background: Missing the diagnosis of stroke and giving a wrong diagnosis potentially causes harm to patients. We aimed at identifying risk factors, causes and outcomes of AIS who were initially not diagnosed upon presentation. Methods: Using a prospectively constructed AIS database (Acute STroke Registry and Analysis of Lausanne, ASTRAL), the population in whom AIS was initial-ly missed (M) over a 8.5 year period was identified. An AIS was considered “missed” if either the initial evaluation by non-neurologists or the neurological consultation concluded with a non-stroke diagnosis, but later, a stroke was confirmed by imaging. Clinical and laboratory data in M were compared to patients with a correct initial diagnosis (D). Results: In 2’200 consecutive AIS, 47 were initially missed (2.1%). In multivariate analysis, M were younger (OR 0.98) which was ex-plained by a bimodal age distribution with a lower peak at age 32. M also had less cerebrovascular risk factors reflected by rarer prestroke use of hipolipemic drugs (OR 0.26) and a lower admission diastolic blood pressure (OR 0.98). They had less eye deviation (OR 0.20) and more cerebellar strokes (OR 3,67). Initial stroke severity showed a bimodal distribution in M with either mild or very severe stroke presenting as coma (NIHSS peaks at 4 and 29). The wrong diagnosis given was most frequently another neurological disease (n=20, 42,5%) such as peripheral vertigo or CNS in-flammation, and coma of non-vascular origin (n=10, 21.2%). Also, 5 AIS (10.6%) were attributed to a simultaneously present medical, neurological and psychiatric disorder. In 2 patients (4.3%), radio-logical data were misinterpreted. Analysis of functional outcome, mortality and recurrences at one year will be presented. Discussion:Strokes may be missed in patients with few vascular risk factors and a lower age who are presenting with lower stroke severity, isolated vertigo, absent eye devia-tion, or who are presenting as coma. At-risk circumstances include the presence of a second medical, neurological or psychiatric disorder, potentially masking the stroke. Knowledge of such risk factors for missing acute ischemic stroke may decrease its incidence.
Karger_ESC London_2013
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