Cerebral Amyloid Angiopathy-Related Inflammation and Biopsy-Positive Primary Angiitis of the CNS: A Comparative Study.

BACKGROUND AND OBJECTIVES: Cerebral amyloid angiopathy-related inflammation (CAA-RI) and biopsy-positive primary angiitis of the CNS (BP-PACNS) have overlapping clinicoradiologic presentations. It is unknown whether clinical and radiologic features can differentiate CAA-RI from BP-PACNS and whether both diseases have different relapse rates. The objectives of this study were to compare clinicoradiologic presentations and relapse rates in patients with CAA-RI vs BP-PACNS. METHODS: Patients with CAA-RI and BP-PACNS were enrolled from 2 retrospective multicenter cohorts. Patients with CAA-RI were biopsy-positive or met probable clinicoradiologic criteria. Patients with BP-PACNS had histopathologic confirmation of CNS angiitis, with no secondary etiology. A neuroradiologist read brain MRIs, blinded to the diagnosis of CAA-RI or BP-PACNS. Clinicoradiologic features were compared using univariable logistic regression models. Relapse rates were compared using a univariable Fine-Gray subdistribution hazard model, with death as a competing risk. RESULTS: This study enrolled 104 patients with CAA-RI (mean age 73 years, 48% female sex) and 52 patients with BP-PACNS (mean age 45 years, 48% female sex). Patients with CAA-RI more often had white matter hyperintense lesions meeting the probable CAA-RI criteria (93% vs 51%, p < 0.001), acute subarachnoid hemorrhage (15% vs 2%, p = 0.02), cortical superficial siderosis (27% vs 4%, p < 0.001), ≥1 lobar microbleed (94% vs 26%, p < 0.001), past intracerebral hemorrhage (17% vs 4%, p = 0.04), ≥21 visible centrum semiovale perivascular spaces (34% vs 4%, p < 0.01), and leptomeningeal enhancement (70% vs 27%, p < 0.001). Patients with BP-PACNS more often had headaches (56% vs 31%, p < 0.01), motor deficits (56% vs 36%, p = 0.02), and nonischemic parenchymal gadolinium enhancement (82% vs 16%, p < 0.001). The prevalence of acute ischemic lesions was 18% in CAA-RI and 22% in BP-PACNS (p = 0.57). The features with the highest specificity for CAA-RI were acute subarachnoid hemorrhage (98%), cortical superficial siderosis (96%), past intracerebral hemorrhage (96%), and ≥21 visible centrum semiovale perivascular spaces (96%). The probable CAA-RI criteria had a 71% sensitivity (95% CI 44%-90%) and 91% specificity (95% CI 79%-98%) in differentiating biopsy-positive CAA-RI from BP-PACNS. The rate of relapse in the first 2 years after remission was lower in CAA-RI than in BP-PACNS (hazard ratio 0.46, 95% CI 0.22-0.96, p = 0.04). CONCLUSION: Clinicoradiologic features differed between patients with CAA-RI and those with BP-PACNS. Specific markers for CAA-RI were hemorrhagic signs of subarachnoid involvement, past intracerebral hemorrhage, ≥21 visible centrum semiovale perivascular spaces, and the probable CAA-RI criteria. A biopsy remains necessary for diagnosis in some cases of CAA-RI. The rate of relapse in the first 2 years after disease remission was lower in CAA-RI than in BP-PACNS.

Comparison of patients with biopsy positive and negative primary angiitis of the central nervous system.

OBJECTIVE: There is limited evidence on when to obtain a central nervous system (CNS) biopsy in suspected primary angiitis of the central nervous system (PACNS). Our objective was to identify which clinical and radiological characteristics were associated with a positive biopsy in PACNS. METHODS: From the multicenter retrospective Cohort of Patients with Primary Vasculitis of the CNS (COVAC), we included adults with PACNS based on a positive CNS biopsy or otherwise unexplained intracranial stenoses with additional findings supportive of vasculitis. Baseline findings were compared between patients with a positive and negative biopsy using logistic regression models. RESULTS: 200 patients with PACNS were included, among which a biopsy was obtained in 100 (50%) and was positive in 61 (31%). Patients with a positive biopsy were more frequently female (OR 2.90, 95% CI 1.25-7.10, p = 0.01) and more often presented with seizures (OR 8.31, 95% CI 2.77-33.04, p < 0.001) or cognitive impairment (OR 2.58, 95% CI 1.11-6.10, p = 0.03). On imaging, biopsy positive patients more often had non-ischemic parenchymal or leptomeningeal gadolinium enhancement (OR 52.80, 95% CI 15.72-233.06, p < 0.001) or ≥ 1 cerebral microbleed (OR 8.08, 95% CI 3.03-25.13, p < 0.001), and less often had ≥ 1 acute brain infarct (OR 0.02, 95% CI 0.004-0.08, p < 0.001). In the multivariable model, non-ischemic parenchymal or leptomeningeal gadolinium enhancement (aOR 8.27, 95% CI 1.78-38.46), p < 0.01) and absence of ≥ 1 acute brain infarct (aOR 0.13, 95% CI 0.03-0.65, p = 0.01) were significantly associated with a positive biopsy. CONCLUSIONS: Baseline clinical and radiological characteristics differed between biopsy positive and negative PACNS. These results may help physicians individualize the decision to obtain a CNS biopsy in suspected PACNS.

Mapping the dynamics of brain perfusion using functional ultrasound in a rat model of transient middle cerebral artery occlusion.

Following middle cerebral artery occlusion, tissue outcome ranges from normal to infarcted depending on depth and duration of hypoperfusion as well as occurrence and efficiency of reperfusion. However, the precise time course of these changes in relation to tissue and behavioral outcome remains unsettled. To address these issues, a three-dimensional wide field-of-view and real-time quantitative functional imaging technique able to map perfusion in the rodent brain would be desirable. Here, we applied functional ultrasound imaging, a novel approach to map relative cerebral blood volume without contrast agent, in a rat model of brief proximal transient middle cerebral artery occlusion to assess perfusion in penetrating arterioles and venules acutely and over six days thanks to a thinned-skull preparation. Functional ultrasound imaging efficiently mapped the acute changes in relative cerebral blood volume during occlusion and following reperfusion with high spatial resolution (100 µm), notably documenting marked focal decreases during occlusion, and was able to chart the fine dynamics of tissue reperfusion (rate: one frame/5 s) in the individual rat. No behavioral and only mild post-mortem immunofluorescence changes were observed. Our study suggests functional ultrasound is a particularly well-adapted imaging technique to study cerebral perfusion in acute experimental stroke longitudinally from the hyper-acute up to the chronic stage in the same subject.

Stroke prevention.

Patients who have had a stroke are at high risk for recurrent stroke, myocardial infarction, and vascular death. Prevention of these events should be initiated promptly after stroke, because many recurrent events occur early, and should be tailored to the precise cause of stroke, which may require specific treatment. Lifestyle advice including abstinence from smoking, regular exercise, Mediterranean-style diet, and reduction of salt intake and alcohol consumption are recommended for all patients with stroke. For most patients with ischemic stroke or TIA, control of risk factors, including lowering blood pressure under 140/90mmHg and LDL cholesterol under 1g/L, together with antiplatelet or oral anticoagulant therapy, depending on the cause of stroke, have been shown to decrease the risk of recurrent stroke and cardiovascular events. Aspirin, clopidogrel, or the combination of aspirin and dipyridamole, are all acceptable options for secondary prevention in patients with ischemic stroke or TIA of arterial origin. Dual therapy with aspirin and clopidogrel might be considered for 3 weeks after a minor ischemic stroke or TIA and for 3 months in patients with stroke due to severe intracranial stenosis. Oral anticoagulants are very effective to prevent cardioembolic stroke. Non-VKA oral anticoagulants have a favorable risk-benefit profile compared with VKAs, with significant reductions in stroke, intracranial hemorrhage, mortality, with similar major bleeding, but increased gastrointestinal bleeding. Carotid endarterectomy reduces the risk of ipsilateral stroke in patients with recent (<6 months) non disabling ischemic stroke or TIA in the territory and severe carotid artery stenosis. Carotid stenting is a potential alternative to surgery in patients younger than ≈70 years or patients with greater risk of surgery due to anatomic or medical conditions or specific circumstances such as radiation-induced stenosis or restenosis after surgery. For patients with hemorrhagic stroke due to hypertension-associated small vessel disease or cerebral amyloid angiopathy, strict control of blood pressure is essential. Restarting oral anticoagulants in patients after intracranial hemorrhage is a difficult decision that should weigh the risks of recurrent ischemic and hemorrhage stroke with and without oral anticoagulants. Several areas of uncertainty persist including the optimal target of blood pressure in patients with cerebrovascular disease, the benefit of PFO closure in patients with PFO-associated stroke, of stenting procedures in patients with atherosclerotic intracranial artery or extracranial vertebral artery stenosis, and of interventional procedures in patients with brain arteriovenous or cavernous malformations.

Clinical Scales Do Not Reliably Identify Acute Ischemic Stroke Patients With Large-Artery Occlusion.

BACKGROUND AND PURPOSE: It remains debated whether clinical scores can help identify acute ischemic stroke patients with large-artery occlusion and hence improve triage in the era of thrombectomy. We aimed to determine the accuracy of published clinical scores to predict large-artery occlusion. METHODS: We assessed the performance of 13 clinical scores to predict large-artery occlusion in consecutive patients with acute ischemic stroke undergoing clinical examination and magnetic resonance or computed tomographic angiography ≤6 hours of symptom onset. When no cutoff was published, we used the cutoff maximizing the sum of sensitivity and specificity in our cohort. We also determined, for each score, the cutoff associated with a false-negative rate ≤10%. RESULTS: Of 1004 patients (median National Institute of Health Stroke Scale score, 7; range, 0-40), 328 (32.7%) had an occlusion of the internal carotid artery, M1 segment of the middle cerebral artery, or basilar artery. The highest accuracy (79%; 95% confidence interval, 77-82) was observed for National Institute of Health Stroke Scale score ≥11 and Rapid Arterial Occlusion Evaluation Scale score ≥5. However, these cutoffs were associated with false-negative rates >25%. Cutoffs associated with an false-negative rate ≤10% were 5, 1, and 0 for National Institute of Health Stroke Scale, Rapid Arterial Occlusion Evaluation Scale, and Cincinnati Prehospital Stroke Severity Scale, respectively. CONCLUSIONS: Using published cutoffs for triage would result in a loss of opportunity for ≥20% of patients with large-artery occlusion who would be inappropriately sent to a center lacking neurointerventional facilities. Conversely, using cutoffs reducing the false-negative rate to 10% would result in sending almost every patient to a comprehensive stroke center. Our findings, therefore, suggest that intracranial arterial imaging should be performed in all patients with acute ischemic stroke presenting within 6 hours of symptom onset.

Relationship between watershed infarcts and recent intra plaque haemorrhage in carotid atherosclerotic plaque.

OBJECTIVE: Watershed infarcts (WSI) are thought to result from hemodynamic mechanism, but studies have suggested that microemboli from unstable carotid plaques may distribute preferentially in watershed areas, i.e., between two cerebral arterial territories. Intraplaque haemorrhage (IPH) is an emerging marker of plaque instability and microembolic activity. We assessed the association between WSI and IPH in patients with recently symptomatic moderate carotid stenosis. METHODS AND RESULTS: We selected 65 patients with symptomatic moderate (median NASCET degree of stenosis = 31%) carotid stenosis and brain infarct on Diffusion-Weighted Imaging (DWI) on Magnetic Resonance Imaging (MRI) from a multicentre prospective study. Fourteen (22%) had WSI (cortical, n = 8; internal, n = 4; cortical and internal, n = 2). Patients with WSI were more likely to have IPH than those without WSI although the difference was not significant (50% vs. 31%, OR = 2.19; 95% CI, 0.66-7.29; P = 0.20). After adjustment for degree of stenosis, age and gender, the results remained unchanged. CONCLUSION: About one in fifth of brain infarcts occurring in patients with moderate carotid stenosis were distributed in watershed areas. Albeit not significant, an association between IPH--more generally plaque component--and WSI, still remains possible.