Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

BackgroundIn patients with stroke, current guidelines recommend non-invasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols.MethodsFrom April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT, CTA and CTP and were treated accordingly. Hypoperfusion areas defined by time-to-maximum of the tissue residue function (Tmax) >6 s, congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated non-contrast CT and CTA to identify intracranial VO (CTA-VO).ResultsOf the 338 patients included in the analysis, 157 (46.5%) presented with CTP-VO (median Tmax >6s: 73 (29–127) mL). CTA-VO was identified in 83 (24.5%) of the cases. Overall CTA-VO sensitivity for the detection of CTP-VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with increased CTA-VO detection (OR 1.03; 95% CI 1.02 to 1.04). EVT was performed in 103 patients (30.5%; Tmax >6s: 102 (63–160) mL), representing 65.6% of all CTP-VO. Overall CTA-VO sensitivity for the detection of EVT-VO was 69.9% and specificity was 95.3%. Among patients who received EVT, the rate of false negative CTA-VO was 30.1% (Tmax >6s: 69 (46–99.5) mL).ConclusionSystematically including CTP in acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

Abstract 1122‐000037: LVO in the Setting of TTP

Introduction : Thrombotic Thrombocytopenic Purpura (TTP) is a disorder of coagulation caused by a deficiency of ADAMTS13 due to either hereditary mutations or acquired autoimmune inhibitors. Low levels of ADAMTS13 metalloprotease leads to Von Willebrand Factor (VWF)‐platelet aggregation and microvascular thrombosis when patients with TTP are exposed to high shear stress in the microcirculation. [1] Hematologic disorder or coagulopathies are the major cause of 1–4% of all ischemic strokes. [2] TTP patients usually present with small vessel strokes or sometimes very distal branches of large arteries. The gold standard treatment for acute stroke in these patients is plasma exchange, however in patients presenting with LVO strokes, recanalization therapies should be considered. [3] Here we present a case of large vessel occlusion stroke in the setting of TTP. Methods : 31‐year‐old African American female with TTP and Strokes admitted to with right sided hemiparesis, and expressive aphasia within 2h of symptom onset. National Institute of Health Stroke Scale (NIHSS) of 16. Laboratory work up significant for Platelets 114k, Hemoglobin 12, PTT 24 seconds, Serum glucose 107, ADAMTS‐13 <1 IU/dL and negative COVID‐19 PCR. CTH showing ASPECTS of 9 (Picture A), CTA head and neck revealing a left MCA occlusion and intracranial vessel irregularities in the left Anterior Cerebral Artery (ACA) and bilateral Posterior Cerebral Arteries (PCA) (Picture B). CTP with 24cc core and 132 cc mismatch (Picture C). Patient was taken to the Angiogram Suite for urgent thrombectomy with a final TICI score of 3 achieved after one pass (Picture D/E). Results : Post procedure NIHSS was 1 for mild expressive aphasia. Brain MRI revealed Left MCA and right parietal territories infarct (Picture F). Transesophageal Echocardiogram was unremarkable. She underwent urgent Plasma Exchange (PLEX) for TTP flair in light of undetectable ADAMTS‐13, significant drop in platelet count and thrombotic event. After 5 PLEX sessions platelets remained stable with counts greater than 150.000. Immunotherapy with Prednisone, Caplacizumab, Atovaquone and Mycophenolate Mofetil was continued and she was discharged home on day 7 from admission. Conclusions : Our patient had severe and refractory disease presenting with LVO and underwent an unusual therapeutic approach considering the etiology of her disease. IV thrombolysis and arterial thrombectomy are well established therapies for acute strokes in the general population, but are rarely performed in patients affected by Thrombotic Microangiopathy (TMA) such as TTP. Safety and efficacy of these procedures have not been studied in this population and it is usually selected by extrapolating data from studies that used individuals without TMA. We aim to illustrate this uncommon case of LVO stroke in the setting of TTP and potentially stimulate the elaboration of studies that include these patients.

Intracranial Involvement in Takayasu’s Arteritis

Takayasu’s arteritis (TAK) is a large-vessel vasculitis that targets the aorta and its major branches. Although extracranial vascular involvement is uniformly present in this disease, the frequency of intracranial involvement in TAK has not been well studied. We retrospectively reviewed the clinical and imaging records of patients diagnosed with TAK at a single Canadian university medical centre to determine the prevalence of intracranial vascular involvement. Intracranial vascular and non-vascular findings were described, and a review of the literature was performed. Of 20 patients with TAK, 12 had vascular neuroimaging completed. Intracranial vascular lesions were identified in 4 patients (33.3% of those with imaging available, 20% of all patients). The frequency of intracranial vessel involvement in TAK may be more common than appreciated. Imaging of both the intra- and extra-cranial vessels should be considered in these young patients.

Progressive Stroke Caused by Neurosyphilis With Concentric Enhancement in the Internal Cerebral Artery on High-Resolution Magnetic Resonance Imaging: A Case Report

Background: Neurosyphilis can initially present as a stroke. However, the general management strategy for stroke may not be effective for this condition. Intracranial vessel wall imaging indicating arteritis can help differentiate neurosyphilis from other causes of stroke.Case presentation: A 59-year-old Chinese woman presented with an acute infarct in the left basal ganglia and multiple stenoses in the bilateral middle cerebral arteries, anterior cerebral artery, and basilar artery, which aggravated twice, despite antiplatelet treatment. High-resolution magnetic resonance imaging (HR-MRI) suggested concentric enhancement in the left middle cerebral artery. Treponema pallidum test results were positive, suggesting neurosyphilis.Conclusions: HR-MRI provides valuable information regarding arteritis, which is helpful in differentiating neurosyphilis from other causes of stroke. Antiplatelet medication should be used judiciously for neurosyphilis-related stroke.

Reasons for Not Performing Mechanical Thrombectomy: A Population-Based Study of Stroke Codes

Background and Purpose: Mechanical thrombectomy (MT) is effective for acute ischemic stroke (AIS) in selected patients with large intracranial vessel occlusion. A minority of patients with AIS receive MT. We aimed to describe the reasons for excluding patients with AIS for MT. Methods: We evaluated patients with AIS in a prospective population-based multicenter registry (Codi Ictus Catalunya registry) that includes all stroke code activations from January to June 2018 in Catalonia, Spain. We analyzed the major reasons for not treating with MT. Results: Stroke code was activated in 3060 patients. Excluding 355 intracranial hemorrhages and 502 stroke mimics, resulted in 2203 patients with AIS (mean age 72.8±13.8 years; 44.6% were women). Of the patients with AIS, 405 (18.4%) were treated with MT. We analyzed the reasons for not treating with MT. The following reasons were considered not modifiable: absence of large intracranial vessel occlusion (922, 41.9%), transient ischemic attack (206, 9.4%), and more than one cause (124, 5.6%). The potentially modifiable reasons for not performing MT by changing selection criteria were as follows: an intracranial artery occlusion that was considered inaccessible or not indicated (48, 2.2%); clinical presentation that was considered too mild to be treated (222, 10.1%); neuroimaging criteria (129, 5.9%), age/prior modified Rankin Scale score/medical comorbidities (129, 5.9%), and therapeutic time window >8 hours (16, 0.7%). Conclusions: In our area, considering all potentially modifiable causes for not performing MT, the percentage of patients with AIS eligible for MT could increase from 18.4% to a maximum of 43.1%. The clinical benefit of this increase is still uncertain and should be confirmed in future trials. Criteria for stroke code activation must be considered for the generalizability of these results.