Proportion of intracerebral haemorrhage due to cerebral amyloid angiopathy in the East and West: Comparison between single hospital centres in Japan and the United Kingdom

Cerebral small vessel disease markers and long-term prognosis in spontaneous intracerebral hemorrhage: the HAGAKURE-ICH study

We investigated the effects of individual and cumulative cerebral small vessel disease (SVD) markers on long-term clinical outcomes in spontaneous intracerebral hemorrhage (sICH) patients. This prospective, single-center cohort study was conducted from 2012 to 2019. SVD markers, including lacunae, cerebral microbleeds, white matter hyperintensity (WMH), and perivascular spaces in the basal ganglia, were assessed to calculate a summary SVD score. Patients were categorized into severe (score ≥3) and non-severe (score 0-2) SVD burden groups. Functional prognosis was defined as recovery, no change, or decline based on modified Rankin Scale changes at 2 years after discharge, excluding death. Associations of SVD burden and individual SVD markers with outcomes were evaluated using Cox proportional hazards modeling for recurrent stroke and all-cause mortality, and using ordinal logistic regression for functional prognosis. Among 155 sICH patients who underwent MRI, 98 showed severe SVD burden. Recurrent stroke and all-cause mortality rates were 2.2 and 8.3 per 100 patient-years, respectively, over a median 2.1-year follow-up. In terms of functional prognosis, 57 patients (51.8%) recovered, 32 (29.1%) showed no change, and 21 (19.1%) declined. A significant association was apparent between severe SVD burden and poorer functional prognosis (odds ratio [OR] 2.48, 95% confidence interval [CI] 1.04-6.04; p = 0.042), particularly with moderate-to-severe WMH (OR 2.54, 95%CI 1.02-6.54; p = 0.048). The cumulative effects of SVD markers inhibited long-term functional recovery in sICH patients. Severe SVD burden, as well as moderate-to-severe WMH, can be indicators of long-term prognosis after sICH.

Prevalence of Cerebral Amyloid Angiopathy Pathology and Strictly Lobar Microbleeds in East-Asian Versus Western Populations: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Possible differences in the prevalence of cerebral amyloid angiopathy (CAA) in East-Asian compared to Western populations have received little attention, and results so far have been ambiguous. Our aim is to compare the prevalence of CAA neuropathology and magnetic resonance imaging markers of CAA in East-Asian and Western cohorts reflecting the general population, cognitively normal elderly, patients with Alzheimer's disease (AD), and patients with (lobar) intracerebral hemorrhage (ICH).

METHODS

We performed a systematic literature search in PubMed and Embase for original research papers on the prevalence of CAA and imaging markers of CAA published up until February 17th 2022. Records were screened by two independent reviewers. Pooled estimates were determined using random-effects models. We compared studies from Japan, China, Taiwan, South Korea (East-Asian cohorts) to studies from Europe or North America (Western cohorts) by meta-regression models.

RESULTS

We identified 12,257 unique records, and we included 143 studies on Western study populations and 53 studies on East-Asian study populations. Prevalence of CAA neuropathology did not differ between East-Asian and Western cohorts in any of the investigated patient domains. The prevalence of strictly lobar microbleeds was lower in East-Asian cohorts of population-based individuals (5.6% vs. 11.4%, P=0.020), cognitively normal elderly (2.6% vs. 11.4%, P=0.001), and patients with ICH (10.2% vs. 24.6%, P<0.0001). However, age was in general lower in the East-Asian cohorts.

CONCLUSION

The prevalence of CAA neuropathology in the general population, cognitively normal elderly, patients with AD, and patients with (lobar) ICH is similar in East-Asian and Western countries. In East-Asian cohorts reflecting the general population, cognitively normal elderly, and patients with ICH, strictly lobar microbleeds were less prevalent, likely due to their younger age. Consideration of potential presence of CAA is warranted in decisions regarding antithrombotic treatment and potential new anti-amyloid-β immunotherapy as treatment for AD in East-Asian and Western countries alike.

Risk factors for intracerebral hemorrhage in small-vessel disease and non-small-vessel disease etiologies-an observational proof-of-concept study

Background

Sporadic cerebral small-vessel disease (CSVD), i.e., hypertensive arteriopathy (HA) and cerebral amyloid angiopathy (CAA), is the main cause of spontaneous intracerebral hemorrhage (ICH). Nevertheless, a substantial portion of ICH cases arises from non-CSVD etiologies, such as trauma, vascular malformations, and brain tumors. While studies compared HA- and CAA-related ICH, non-CSVD etiologies were excluded from these comparisons and are consequently underexamined with regard to additional factors contributing to increased bleeding risk beyond their main pathology.

Methods

As a proof of concept, we conducted a retrospective observational study in 922 patients to compare HA, CAA, and non-CSVD-related ICH with regard to factors that are known to contribute to spontaneous ICH onset. Medical records (available for n = 861) were screened for demographics, antithrombotic medication, and vascular risk profile, and CSVD pathology was rated on magnetic resonance imaging (MRI) in a subgroup of 185 patients. The severity of CSVD was assessed with a sum score ranging from 0 to 6, where a score of ≥2 was defined as advanced pathology.

Results

In 922 patients with ICH (median age of 71 years), HA and CAA caused the majority of cases (n = 670, 73%); non-CSVD etiologies made up the remaining quarter (n = 252, 27%). Individuals with HA- and CAA-related ICH exhibited a higher prevalence of predisposing factors than those with non-CSVD etiologies. This includes advanced age (median age: 71 vs. 75 vs. 63 years, p < 0.001), antithrombotic medication usage (33 vs. 37 vs. 19%, p < 0.001), prevalence of vascular risk factors (70 vs. 67 vs. 50%, p < 0.001), and advanced CSVD pathology on MRI (80 vs. 89 vs. 51%, p > 0.001). However, in particular, half of non-CSVD ICH patients were either aged over 60 years, presented with vascular risk factors, or had advanced CSVD on MRI.

Conclusion

Risk factors for spontaneous ICH are less common in non-CSVD ICH etiologies than in HA- and CAA-related ICH, but are still frequent. Future studies should incorporate these factors, in addition to the main pathology, to stratify an individual's risk of bleeding.

Associations for progression of cerebral small vessel disease burden in healthy adults: the Kashima scan study

To investigate the association between vascular risk factors and progression of cerebral small vessel disease (SVD), we conducted a longitudinal study with neurologically healthy cohort composed mostly of middle-aged adults (n = 665, mean age, 57.7 years). Subjects, who had both baseline data of brain health examinations including MRI and follow-up MRI at least 1 year after the baseline MRI, were included this study. The presence of features of SVD, including lacunes, cerebral microbleeds, white matter hyperintensity, and basal ganglia perivascular spaces were summed to obtain "total SVD score" (range, 0-4). Progression of SVD was evaluated among subjects with a total SVD score of ≤ 3 and was defined as a ≥ 1 point increase in that score at follow-up relative to baseline. As the primary analysis, multivariate logistic regression analyses were performed to determine the associations of progression of SVD at baseline. The median follow-up period was 7.3 years and progression of SVD was observed in 154 subjects (23.2%). Even after adjustment with confounders multivariate logistic regression analyses showed that progression of SVD was associated with age (per 10-year increase, odds ratio [OR]: 2.08, 95% confidence interval [CI] 1.62-2.67), hypertension (OR 1.55, 95%CI 1.05-2.29), systolic blood pressure (BP) (per standard deviation [SD] increase, OR 1.27, 95%CI 1.04-1.54), diastolic BP (per SD increase, OR 1.23, 95%CI 1.01-1.50), and mean arterial pressure (per SD increase, OR 1.27, 95%CI 1.04-1.55). Age and high blood pressure appear to play key roles in the progression of cerebral small vessel burden after mid-life.

Intravenous nicardipine for Japanese patients with acute intracerebral hemorrhage: an individual participant data analysis

The effects of acute systolic blood pressure levels achieved with continuous intravenous administration of nicardipine for Japanese patients with acute intracerebral hemorrhage on clinical outcomes were determined. A systematic review and individual participant data analysis of articles were performed based on prospective studies involving adults developing hyperacute intracerebral hemorrhage who were treated with intravenous nicardipine. Outcomes included death or disability at 90 days, defined as the modified Rankin Scale score of 4-6, and hematoma expansion, defined as an increase 6 mL or more from baseline to 24 h computed tomography. Of the total 499 Japanese patients (age 64.9 ± 11.8 years, 183 women, initial BP 203.5 ± 18.3/109.1 ± 17.2 mmHg) studied, death or disability occurred in 35.6%, and hematoma expansion occurred in 15.6%. Mean hourly systolic blood pressure during the initial 24 h was positively associated with death or disability (adjusted odds ratio 1.25, 95% confidence interval 1.03-1.52 per 10 mmHg) and hematoma expansion (1.49, 1.18-1.87). These odds ratios were relatively high as compared to the reported ones for overall global patients of this individual participant data analysis [1.12 (95% confidence interval 1.00-1.26) and 1.16 (1.02-1.32), respectively]. In conclusion, lower levels of systolic blood pressure by continuous intravenous nicardipine were associated with lower risks of hematoma expansion and 90-day death or disability in Japanese patients with hyperacute intracerebral hemorrhage. The impact of systolic blood pressure lowering on better outcome seemed to be stronger in Japanese patients than the global ones.

Long-term outcome of cerebral amyloid angiopathy-related hemorrhage

OBJECT

The long-term functional outcome of cerebral amyloid angiopathy-related hemorrhage (CAAH) patients is unclear. We sought to assess the long-term functional outcome of CAAH and determine the prognostic factors associated with unfavorable outcomes.

METHODS

We enrolled consecutive CAAH patients from 2014 to 2020 in this observational study. Baseline characteristics and clinical outcomes were presented. Multivariable logistic regression analysis was performed to identify the prognostic factors associated with long-term outcome.

RESULTS

Among the 141 CAAH patients, 76 (53.9%) achieved favorable outcomes and 28 (19.9%) of them died at 1-year follow-up. For the longer-term follow-up with a median observation time of 19.0 (interquartile range, 12.0-26.5) months, 71 (50.4%) patients obtained favorable outcomes while 33 (23.4%) died. GCS on admission (OR, 0.109; 95% CI, 0.021-0.556; p = 0.008), recurrence of ICH (OR, 2923.687; 95% CI, 6.282-1360730.14; p = 0.011), WML grade 3-4 (OR, 31.007; 95% CI, 1.041-923.573; p = 0.047), severe central atrophy (OR, 4220.303; 95% CI, 9.135-1949674.84; p = 0.008) assessed by CT was identified as independent predictors for long-term outcome.

INTERPRETATION

Nearly 50% of CAAH patients achieved favorable outcomes at long-term follow-up. GCS, recurrence of ICH, WML grade and cerebral atrophy were identified as independent prognostic factors of long-term outcome.

Clinical neuroimaging in intracerebral haemorrhage related to cerebral small vessel disease: contemporary practice and emerging concepts

INTRODUCTION

About 80% of all non-traumatic intracerebral haemorrhage (ICH) are caused by the sporadic cerebral small vessel diseases deep perforator arteriopathy (DPA, also termed hypertensive arteriopathy or arteriolosclerosis) and cerebral amyloid angiopathy (CAA), though these frequently co-exist in older people. Contemporary neuroimaging (MRI and CT) detects an increasing spectrum of haemorrhagic and non-haemorrhagic imaging biomarkers of small vessel disease which may identify the underlying arteriopathies.

AREAS COVERED

We discuss biomarkers for cerebral small vessel disease subtypes in ICH, and explore their implications for clinical practice and research.

EXPERT OPINION

ICH is not a single disease, but results from a defined range of vascular pathologies with important implications for prognosis and treatment. The terms "primary" and "hypertensive" ICH are poorly defined and should be avoided, as they encourage incomplete investigation and classification. Imaging-based criteria for CAA will show improved diagnostic accuracy, but specific imaging biomarkers of DPA are needed. Ultra-high-field 7T-MRI using structural and quantitative MRI may provide further insights into mechanisms and pathophysiology of small vessel disease. We expect neuroimaging biomarkers and classifications to allow personalized treatments (e.g. antithrombotic drugs) in clinical practice and to improve patient selection and monitoring in trials of targeted therapies directed at the underlying arteriopathies.

Controlling blood pressure soon after intracerebral hemorrhage: The SAMURAI-ICH Study and its successors

The impact of acute therapy for intracerebral hemorrhage (ICH) lags far behind that for acute ischemic stroke. Intensive blood pressure lowering is a promising therapeutic strategy for acute ICH, especially for East Asian patients whose etiological mechanism is more commonly hypertension than that of patients in the Western population. A multicenter, prospective, observational study named the Stroke Acute Management with Urgent Risk-factor Assessment and Improvement-IntraCerebral Hemorrhage (SAMURAI-ICH) study, involving 211 patients from ten Japanese stroke centers, was performed to elucidate the safety and feasibility of blood pressure lowering to 160 mmHg or less in acute ICH patients using intravenous nicardipine. When we started the study, intravenous nicardipine was not officially approved for hyperacute ICH patients in Japan. The SAMURAI-ICH study was also a pilot study to judge the feasibility of participation by many Japanese investigators in an international, randomized, controlled trial named the Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH)−2 trial. The SAMURAI-ICH study, ATACH-2 trial, and their combined individual participant data meta-analysis produced several new interesting findings on how to control blood pressure levels in acute ICH patients. Some of the findings are introduced in the present review article.

Disparities in diagnosis of cerebral amyloid angiopathy based on hospital characteristics

Cerebral amyloid angiopathy (CAA) categorized as a cerebral small vessel disease can cause lobar intracerebral hemorrhage (ICH), convexity subarachnoid hemorrhage (SAH) and ischemic stroke (IS). The purpose of this study was to evaluate the differences in the diagnosis of CAA based on hospital characteristics and to assess the discharge outcomes of patients with CAA admitted for IS, ICH and SAH. Adult patients admitted with secondary diagnosis of CAA were identified in National Inpatient Sample in 2016 and 2017. Multivariable logistic regression analysis was performed to evaluate outcomes. A total of 16,040 patients had a secondary diagnosis of CAA. Among CAA patients, 1810 (11.3%) patients were admitted for IS, 4765 (29.7%) for ICH and 490 (3.1%) for SAH. Diagnosis of CAA was five-fold higher among patients admitted to urban teaching hospitals (aOR = 5.4;95% CI = 4.1-7.2) compared to rural hospitals and two-fold higher in large bed size hospitals (aOR = 2.3;95% CI = 2.0-2.7) compared to small bed size hospitals. Compared to non-CAA group, patients with history of CAA had lower odds of in-hospital mortality among patients admitted for ICH (10% vs 23%, aOR = 0.35; 95%CI = 0.27-0.44) and SAH (6% vs 19%, aOR = 0.24; 95%CI = 0.10-0.55); and higher odds of discharge to home among patients admitted for ICH (17% vs 18%, aOR = 1.27; 95%CI = 1.05-1.53). CAA diagnosis is less common in rural and small bed size hospitals compared to urban and large bedside hospitals, respectively. Patients with CAA admitted for ICH have better discharge outcomes compared to non-CAA patients admitted for ICH.

Taxifolin: A Potential Therapeutic Agent for Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of β-amyloid (Aβ) in the walls of cerebral vessels, leading to complications such as intracerebral hemorrhage, convexity subarachnoid hemorrhage and cerebral microinfarcts. Patients with CAA-related intracerebral hemorrhage are more likely to develop dementia and strokes. Several pathological investigations have demonstrated that more than 90% of Alzheimer's disease patients have concomitant CAA, suggesting common pathogenic mechanisms. Potential causes of CAA include impaired Aβ clearance from the brain through the intramural periarterial drainage (IPAD) system. Conversely, CAA causes restriction of IPAD, limiting clearance. Early intervention in CAA could thus prevent Alzheimer's disease progression. Growing evidence has suggested Taxifolin (dihydroquercetin) could be used as an effective therapy for CAA. Taxifolin is a plant flavonoid, widely available as a health supplement product, which has been demonstrated to exhibit anti-oxidative and anti-inflammatory effects, and provide protection against advanced glycation end products and mitochondrial damage. It has also been shown to facilitate disassembly, prevent oligomer formation and increase clearance of Aβ in a mouse model of CAA. Disturbed cerebrovascular reactivity and spatial reference memory impairment in CAA are completely prevented by Taxifolin treatment. These results highlight the need for clinical trials on the efficacy and safety of Taxifolin in patients with CAA.