Clinical significance of amyloid ß positivity in patients with probable cerebral amyloid angiopathy markers.

PURPOSE: We investigated the frequency and clinical significance of amyloid ß (Aß) positivity on PET in patients with cerebral amyloid angiopathy (CAA). METHODS: We recruited 65 patients who met the modified Boston criteria for probable CAA. All underwent amyloid PET, MRI, APOE genotyping and neuropsychological testing, and we obtained information on MRI markers of CAA and ischemic cerebral small-vessel disease (CSVD). We investigated the CAA/ischemic CSVD burden and APOE genotypes in relation to Aß positivity and investigated the effect of Aß positivity on longitudinal cognitive decline. RESULTS: Among the 65 CAA patients, 43 (66.2%) showed Aß PET positivity (Aß+). Patients with Aß+ CAA had more lobar microbleeds (median 9, interquartile range 2-41, vs. 3, 2-8; P = 0.045) and a higher frequency of cortical superficial siderosis (34.9% vs. 9.1%; P = 0.025), while patients with Aß- CAA had more lacunes (1, 0-2, vs. 0, 0-1; P = 0.029) and a higher frequency of severe white matter hyperintensities (45.5% vs. 20.9%; P = 0.040). The frequency of ε4 carriers was higher in Aß+ patients (57.1%) than in Aß- patients (18.2%; P = 0.003), while the frequency of ε2 carriers did not differ between the two groups. Finally, Aß positivity was associated with faster decline in multiple cognitive domains including language (P < 0.001), visuospatial function (P < 0.001), and verbal memory (P < 0.001) in linear mixed effects models. CONCLUSION: Our findings suggest that a significant proportion of patients with probable CAA in a memory clinic are Aß- on PET. Aß positivity in CAA patients is associated with a distinct pattern of CSVD biomarker expression, and a worse cognitive trajectory. Aß positivity has clinical relevance in CAA and might represent either advanced CAA or additional Alzheimer's disease neuropathological changes.

Atrial fibrillation and stroke: a practical guide.

Neurologists and stroke physicians will be familiar with atrial fibrillation as a major cause of ischaemic stroke, and the role of anticoagulation in preventing cardioembolic stroke. However, making decisions about anticoagulation for individual patients remains a difficult area of clinical practice, balancing the serious risk of ischaemic stroke against that of major bleeding, particularly intracranial haemorrhage. Atrial fibrillation management requires interdisciplinary collaboration with colleagues in cardiology and haematology. Recent advances, especially the now-widespread availability of direct oral anticoagulants, have brought opportunities to improve stroke care while posing new challenges. This article gives an overview of the contemporary diagnosis and management of atrial fibrillation, and the associated evidence base. Where there is uncertainty, we describe our own approach to these areas, while highlighting ongoing research that will likely guide future practice.

Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy: international individual patient data pooled analysis.

OBJECTIVE: To investigate the frequency, time-course and predictors of intracerebral haemorrhage (ICH), recurrent convexity subarachnoid haemorrhage (cSAH), and ischemic stroke after cSAH associated with cerebral amyloid angiopathy (CAA). METHODS: We performed a systematic review and international individual patient-data pooled analysis in patients with cSAH associated with probable or possible CAA diagnosed on baseline MRI using the modified Boston criteria. We used Cox proportional hazards models with a frailty term to account for between-cohort differences. RESULTS: We included 190 patients (mean age 74.5 years; 45.3% female) from 13 centers with 385 patient-years of follow-up (median 1.4 years). The risks of each outcome (per patient-year) were: ICH 13.2% (95% CI 9.9-17.4); recurrent cSAH 11.1% (95% CI 7.9-15.2); combined ICH, cSAH, or both 21.4% (95% CI 16.7-26.9), ischemic stroke 5.1% (95% CI 3.1-8) and death 8.3% (95% CI 5.6-11.8). In multivariable models, there is evidence that patients with probable CAA (compared to possible CAA) had a higher risk of ICH (HR 8.45, 95% CI 1.13-75.5, p = 0.02) and cSAH (HR 3.66, 95% CI 0.84-15.9, p = 0.08) but not ischemic stroke (HR 0.56, 95% CI 0.17-1.82, p = 0.33) or mortality (HR 0.54, 95% CI 0.16-1.78, p = 0.31). CONCLUSIONS: Patients with cSAH associated with probable or possible CAA have high risk of future ICH and recurrent cSAH. Convexity SAH associated with probable (vs possible) CAA is associated with increased risk of ICH, and cSAH but not ischemic stroke. Our data provide precise risk estimates for key vascular events after cSAH associated with CAA which can inform management decisions.

Clinical features distinguish cerebral amyloid angiopathy-associated convexity subarachnoid haemorrhage from suspected TIA.

OBJECTIVE: To identity clinical features that distinguish between cerebral amyloid angiopathy (CAA)-associated convexity subarachnoid haemorrhage (cSAH) and suspected TIA. METHODS: We undertook a single-centre, retrospective case-control study. We identified cases [patients with cSAH presenting with transient focal neurological episodes (TFNE)] from radiological and clinical databases of patients assessed at the National Hospital for Neurology and Neurosurgery and UCLH Comprehensive Stroke Service. We identified age- and gender-matched controls at a 1:4 ratio from a database of consecutive suspected TIA clinic attendances at UCLH. We compared presenting symptoms and vascular risk factors between cases and controls. RESULTS: We included 19 patients with cSAH-associated TFNE and 76 matched controls with suspected TIA. Migratory (spreading) symptoms (32% vs. 3%, OR 17.3; p = 0.001), sensory disturbance (47% vs. 14%, OR 5.3; p = 0.003,) and recurrent stereotyped events (47% vs. 19%, OR 3.7; p = 0.02,) occurred more frequently in patients with cSAH compared to controls. Hypercholesterolaemia was less common in patients with cSAH (16% vs 53%, OR 0.17; p = 0.008). CONCLUSION: Simple clinical features could help distinguish cSAH-associated TFNE from suspected TIA, with relevance for investigation and management, including the use of antithrombotic drugs.

Increased resting cerebral blood flow in adult Fabry disease: MRI arterial spin labeling study.

OBJECTIVE: To assess resting cerebral blood flow (CBF) in the whole-brain and cerebral white matter (WM) and gray matter (GM) of adults with Fabry disease (FD), using arterial spin labeling (ASL) MRI, and to investigate CBF correlations with WM hyperintensity (WMH) volume and the circulating biomarker lyso-Gb3. METHODS: This cross-sectional, case-control study included 25 patients with genetically confirmed FD and 18 age-matched healthy controls. We quantified resting CBF using Quantitative Signal Targeting With Alternating Radiofrequency Labeling of Arterial Regions (QUASAR) ASL MRI. We measured WMH volume using semiautomated software. We measured CBF in regions of interest in whole-brain, WM, and deep GM, and assessed correlations with WMH volume and plasma lyso-Gb3. RESULTS: The mean age (% male) for FD and healthy controls was 42.2 years (44%) and 37.1 years (50%). Mean whole-brain CBF was 27.56 mL/100 mL/min (95% confidence interval [CI] 23.78-31.34) for FD vs 22.39 mL/100 mL/min (95% CI 20.08-24.70) for healthy controls, p = 0.03. In WM, CBF was higher in FD (22.42 mL/100 mL/min [95% CI 17.72-27.12] vs 16.25 mL/100 mL/min [95% CI 14.03-18.48], p = 0.05). In deep GM, CBF was similar between groups (40.41 mL/100 mL/min [95% CI 36.85-43.97] for FD vs 37.46 mL/100 mL/min [95% CI 32.57-42.35], p = 0.38). In patients with FD with WMH (n = 20), whole-brain CBF correlated with WMH volume (r = 0.59, p = 0.006), not with plasma lyso-Gb3. CONCLUSION: In FD, resting CBF is increased in WM but not deep GM. In FD, CBF correlates with WMH, suggesting that cerebral perfusion changes might contribute to, or result from, WM injury.

Total MRI Small Vessel Disease Burden Correlates with Cognitive Performance, Cortical Atrophy, and Network Measures in a Memory Clinic Population.

BACKGROUND: Recent evidence suggests that combining individual imaging markers of cerebral small vessel disease (SVD) may more accurately reflect its overall burden and better correlate with clinical measures. OBJECTIVE: We wished to establish the clinical relevance of the total SVD score in a memory clinic population by investigating the association with SVD score and cognitive performance, cortical atrophy, and structural network measures, after adjusting for amyloid-ß burden. METHODS: We included 243 patients with amnestic mild cognitive impairment (MCI), Alzheimer's disease dementia, subcortical vascular MCI, or subcortical vascular dementia. All underwent MR and [11C] PiB-PET scanning and had standardized cognitive testing. Multiple linear regression was used to evaluate the relationships between SVD score and cognition, cortical thickness, and structural network measures. Path analyses were performed to evaluate whether network disruption mediates the effects of SVD score on cortical thickness and cognition. RESULTS: Total SVD score was associated with the performance of frontal (ß - 4.31, SE 2.09, p = 0.040) and visuospatial (ß - 0.95, SE 0.44, p = 0.032) tasks, and with reduced cortical thickness in widespread brain regions. Total SVD score was negatively correlated with nodal efficiency, as well as changes in brain network organization, with evidence of reduced integration and increasing segregation. Path analyses showed that the associations between SVD score and frontal and visuospatial scores were partially mediated by decreases in their corresponding nodal efficiency and cortical thickness. CONCLUSION: Total SVD burden has clinical relevance in a memory clinic population and correlates with cognition, and cortical atrophy, as well as structural network disruption.

Prevalence and mechanisms of cortical superficial siderosis in cerebral amyloid angiopathy.

OBJECTIVE: We investigated the prevalence and clinical-radiologic associations of cortical superficial siderosis (cSS) in patients with probable cerebral amyloid angiopathy (CAA) compared to those with intracerebral hemorrhage (ICH) not attributed to CAA. METHODS: We conducted a retrospective multicenter cohort study of 120 patients with probable CAA and 2 comparison groups: 67 patients with either single lobar ICH or mixed (deep and lobar) hemorrhages; and 22 patients with strictly deep hemorrhages. We rated cSS, ICH, white matter changes, and cerebral microbleeds. RESULTS: cSS was detected in 48 of 120 (40%; 95% confidence interval [CI]: 31.2%-49.3%) patients with probable CAA, 10 of 67 (14.9%; 95% CI: 7.4%-25.7%) with single lobar ICH or mixed hemorrhages, and 1 of 22 (4.6%; 95% CI: 0.1%-22.8%) patients with strictly deep hemorrhages (p < 0.001 for trend). Disseminated cSS was present in 29 of 120 (24%; 95% CI: 16.8%-32.8%) patients with probable CAA, but none of the other patients with ICH (p < 0.001). In probable CAA, age (odds ratio [OR]: 1.09; 95% CI: 1.03-1.15; p = 0.002), chronic lobar ICH (OR: 3.94; 95% CI: 1.54-10.08; p = 0.004), and a history of transient focal neurologic episodes (OR: 11.08; 95% CI: 3.49-35.19; p < 0.001) were independently associated with cSS. However, cSS occurred in 17 of 48 patients with probable CAA (35.4%; 95% CI: 22.2%-50.5%) without chronic lobar ICH. CONCLUSIONS: cSS (particularly if disseminated) is a common and characteristic feature of CAA. Chronic lobar ICH is an independent risk factor for cSS, but the causal direction and mechanism of association are uncertain. Hemorrhage into the subarachnoid space, independent of previous (chronic) lobar ICH, must also contribute to cSS in CAA. Transient focal neurologic episodes are the strongest clinical marker of cSS.

Cortical superficial siderosis and intracerebral hemorrhage risk in cerebral amyloid angiopathy.

OBJECTIVE: To investigate whether cortical superficial siderosis (cSS) on MRI, especially if disseminated (involving more than 3 sulci), increases the risk of future symptomatic lobar intracerebral hemorrhage (ICH) in cerebral amyloid angiopathy (CAA). METHODS: European multicenter cohort study of 118 patients with CAA (104 with baseline symptomatic lobar ICH) diagnosed according to the Boston criteria. We obtained baseline clinical, MRI, and follow-up data on symptomatic lobar ICH. Using Kaplan-Meier and Cox regression analyses, we investigated cSS and ICH risk, adjusting for known confounders. RESULTS: During a median follow-up time of 24 months (interquartile range 9-44 months), 23 of 118 patients (19.5%, 95% confidence interval [CI]: 12.8%-27.8%) experienced symptomatic lobar ICH. Any cSS and disseminated cSS were predictors of time until first or recurrent ICH (log-rank test: p = 0.0045 and p = 0.0009, respectively). ICH risk at 4 years was 25% (95% CI: 7.6%-28.3%) for patients without siderosis; 28.9% (95% CI: 7.7%-76.7%) for patients with focal siderosis; and 74% (95% CI: 44.1%-95.7%) for patients with disseminated cSS (log-rank test: p = 0.0031). In Cox regression models, any cSS and disseminated cSS were both independently associated with increased lobar ICH risk, after adjusting for ≥ 2 microbleeds and age (hazard ratio: 2.53; 95% CI: 1.05-6.15; p = 0.040 and hazard ratio: 3.16; 95% CI: 1.35-7.43; p = 0.008, respectively). These results remained consistent in sensitivity analyses including only patients with symptomatic lobar ICH at baseline. CONCLUSIONS: Our findings indicate that cSS, particularly if disseminated, is associated with an increased risk of symptomatic lobar ICH in CAA. cSS may help stratify future bleeding risk in CAA, with implications for prognosis and treatment.