Statins in Intracerebral Hemorrhage

Effect of statin therapy patterns on readmission and mortality in patients with intracerebral hemorrhage

There is limited and inconsistent evidence for the association of statin therapy and statin treatment patterns with the risk of recurrent intracerebral hemorrhage (ICH) in patients with prior ICH. To assess the association of statin therapy and its intensity, type, initiation time, and discontinuation with the risk of recurrent ICH and mortality in Chinese patients with ICH. Patients with newly diagnosed ICH in the Beijing Employee Medical Claims Data database from 2010 to 2017 were included. Post-ICH statin users (post-diagnosis only) and nonusers (never), statin discontinuers (pre-diagnosis only) and continuers (pre- and post-diagnosis) were matched on a 1:1 propensity score, respectively. Adjusted Cox proportional risk models were used to estimate the risk ratios for ICH readmission and mortality under various statin patterns. A total of 2668 post-ICH statin users and 2668 nonusers without a history of statin use were enrolled. Post-ICH statin users had a lower risk of ICH readmission (HR, 0.57; 95% CI 0.48, 0.69) and all-cause death (0.56: 0.49, 0.63) than nonusers. Low/moderate-intensity treatment was associated with a 63% lower risk of recurrent ICH compared with nonusers (0.37: 0.29, 0.46), whereas high-intensity treatment did not reduce the risk (0.93: 0.74, 1.16). Both low/moderate-intensity (0.42: 0.36, 0.48) and high-intensity statins (0.57: 0.48, 0.69) were associated with a lower risk of all-cause mortality. The risk of ICH readmission was 53% (0.47: 0.30, 0.74) lower with adherence to rosuvastatin than with atorvastatin. Only starting medication within 30 days of the first diagnosis of ICH reduced the risk of ICH readmission (0.49: 0.40, 0.60). Among patients with a history of statin use, 1807 discontinuing and 1,807 continuing users of statins were included. The risk of ICH readmission (4.00: 3.32, 4.80) and the risk of all-cause death (4.01: 3.57, 4.50) were substantially increased in statin discontinuation compared with continued statin use. Statin therapy after ICH was associated with lower risks for ICH readmission and all-cause mortality compared with non-statin therapy, especially at low/moderate intensity and early initiation of statins after ICH. Adherence to rosuvastatin was associated with a lower risk of recurrence of ICH than atorvastatin. Among patients with a statin history prior to ICH, discontinuation of statins after ICH was associated with increased risk of ICH recurrence and death.

Is statin therapy after ischaemic stroke associated with increased intracerebral hemorrhage? The association may be dependent on intensity of statin therapy

BACKGROUND

There has been concern that statin therapy may be associated with an increased risk of intracerebral hemorrhage (ICH). We investigated whether the intensity and type of statin therapy instituted after ischemic stroke (IS) were associated with risk of future ICH in a region of northern China with a high incidence of stroke.

METHODS

Newly diagnosed IS patients who were not treated with lipid-lowering drugs in the Beijing Employee Medical Claims Data database from 2010 to 2017 were included. The primary exposure variable was any statin prescription within 1 month of the first documented stroke diagnosis. High-intensity statin therapy was defined as atorvastatin ⩾ 80 mg, simvastatin ⩾ 80 mg, pravastatin ⩾ 40 mg, and rosuvastatin ⩾ 20 mg per day or equivalent combination. An adjusted Cox proportional hazards model was used to estimate the hazard ratio (HR) for ICH during follow-up in groups exposed and not exposed to statins.

RESULTS

Of 62,252 participants with IS and 628 ICH readmissions were recorded during a median follow-up of 3.17 years. The risk of ICH among statin users (N = 43,434) was similar to that among nonusers (N = 18,818) with an adjusted HR and 95% confidence interval (CI) of 0.86 (0.73, 1.02). Compared with non-statin therapy, patients with low/moderate-intensity therapy had a lower risk of ICH (0.62: 0.52, 0.75), while patients with high-intensity therapy had a substantially higher risk (2.12: 1.72, 2.62). For patients with different types of statin therapy, adherence to rosuvastatin had the lowest risk of ICH compared to adherence to atorvastatin (0.46: 0.34, 0.63), followed by simvastatin (0.60: 0.45, 0.81).

CONCLUSION

In patients with IS, any statin therapy was not associated with an increased risk of ICH. However there appeared to be differential risk according to the dose of statin with high-intensity statin therapy being associated with an increased risk of ICH, while low/moderate-intensity therapy was associated with a lower risk.

Genetically predicted on-statin LDL response is associated with higher intracerebral haemorrhage risk

Statins lower low-density lipoprotein cholesterol and are widely used for the prevention of atherosclerotic cardiovascular disease. Whether statin-induced low-density lipoprotein reduction increases risk of intracerebral haemorrhage has been debated for almost two decades. Here, we explored whether genetically predicted on-statin low-density lipoprotein response is associated with intracerebral haemorrhage risk using Mendelian randomization. Using genomic data from randomized trials, we derived a polygenic score from 35 single nucleotide polymorphisms of on-statin low-density lipoprotein response and tested it in the population-based UK Biobank. We extracted statin drug and dose information from primary care data on a subset of 225 195 UK Biobank participants covering a period of 29 years. We validated the effects of the genetic score on longitudinal low-density lipoprotein measurements with generalized mixed models and explored associations with incident intracerebral haemorrhage using Cox regression analysis. Statins were prescribed at least once to 75 973 (31%) of the study participants (mean 57 years, 55% females). Among statin users, mean low-density lipoprotein decreased by 3.45 mg/dl per year [95% confidence interval (CI): (-3.47, -3.42)] over follow-up. A higher genetic score of statin response [1 standard deviation (SD) increment] was associated with significant additional reductions in low-density lipoprotein levels [-0.05 mg/dl per year, (-0.07, -0.02)], showed concordant lipidomic effects on other lipid traits as statin use and was associated with a lower risk for incident myocardial infarction [hazard ratio per SD increment 0.98 95% CI (0.96, 0.99)] and peripheral artery disease [hazard ratio per SD increment 0.93 95% CI (0.87, 0.99)]. Over a 11-year follow-up period, a higher genetically predicted statin response among statin users was associated with higher intracerebral haemorrhage risk in a model adjusting for statin dose [hazard ratio per SD increment 1.16, 95% CI (1.05, 1.28)]. On the contrary, there was no association with intracerebral haemorrhage risk among statin non-users (P = 0.89). These results provide further support for the hypothesis that statin-induced low-density lipoprotein reduction may be causally associated with intracerebral haemorrhage risk. While the net benefit of statins for preventing vascular disease is well-established, these results provide insights about the personalized response to statin intake and the role of pharmacological low-density lipoprotein lowering in the pathogenesis of intracerebral haemorrhage.

Molecular mechanisms underlying some major common risk factors of stroke

Ischemic and hemorrhagic strokes are the most common known cerebrovascular disease which can be induced by modifiable and non-modifiable risk factors. Age and race are the most common non-modifiable risk factors of stroke. However, hypertension, diabetes, obesity, dyslipidemia, physical inactivity, and cardiovascular disorders are major modifiable risk factors. Understanding the molecular mechanism mediating each of these risk factors is expected to contribute significantly to reducing the risk of stroke, preventing neural damage, enhancing rehabilitation, and designing suitable treatments. Abnormalities in the structure of the blood-brain barrier and blood vessels, thrombosis, vasoconstriction, atherosclerosis, reduced cerebral blood flow, neural oxidative stress, inflammation, and apoptosis, impaired synaptic transmission, excitotoxicity, altered expression/activities of many channels and signaling proteins are the most knows mechanisms responsible for stroke induction. However, the molecular role of risk factors in each of these mechanisms is not well understood and requires a lot of search and reading. This review was designed to provide the reader with a single source of information that discusses the current update of the prevalence, pathophysiology, and all possible molecular mechanisms underlying some major risk factors of stroke namely, hypertension, diabetes mellitus, dyslipidemia, and lipid fraction, and physical inactivity. This provides a full resource for understanding the molecular effect of each of these risk factors in stroke.

[An overview of risk factors for stroke]

Stroke is a heterogeneous syndrome, and the definition of risk factors, treatment and prevention tactics depends on the specific pathogenesis of the disease. Risk factors for ischemic and hemorrhagic stroke are similar, but at the same time there are significant differences. The concept of stroke triggers is discussed separately. In addition, a deep understanding of the pathogenetic mechanisms and the development of new strategies for therapy and prevention require an understanding of the genetic mechanisms of stroke risk. Genetic factors may be more modifiable than previously thought. To reduce the burden of stroke in the population, timely identification and management of modifiable risk factors is essential.

A practical approach to the management of cerebral amyloid angiopathy

Cerebral amyloid angiopathy is a common small vessel disease in the elderly involving vascular amyloid-β deposition. Cerebral amyloid angiopathy is one of the leading causes of intracerebral hemorrhage and a significant contributor to age-related cognitive decline. The awareness of a diagnosis of cerebral amyloid angiopathy is important in clinical practice as it impacts decisions to use lifelong anticoagulation or nonpharmacological alternatives to anticoagulation such as left atrial appendage closure in patients who have concurrent atrial fibrillation, another common condition in older adults. This review summarizes the latest literature regarding the management of patients with sporadic cerebral amyloid angiopathy, including diagnostic criteria, imaging biomarkers for cerebral amyloid angiopathy severity, and management strategies to decrease intracerebral hemorrhage risk. In a minority of patients, the presence of cerebral amyloid angiopathy triggers an autoimmune inflammatory reaction, referred to as cerebral amyloid angiopathy-related inflammation, which is often responsive to immunosuppressive treatment in the acute phase. Diagnosis and management of cerebral amyloid angiopathy-related inflammation will be presented separately. While there are currently no effective therapeutics available to cure or halt the progression of cerebral amyloid angiopathy, we discuss emerging avenues for potential future interventions.

Strictly Lobar Microbleeds Reflect Amyloid Angiopathy Regardless of Cerebral and Cerebellar Compartments

BACKGROUND AND PURPOSE

We aimed to determine whether lobar cerebellar microbleeds or concomitant lobar cerebellar and deep microbleeds, in the presence of lobar cerebral microbleeds, attribute to underlying advanced cerebral amyloid angiopathy pathology or hypertensive arteriopathy.

METHODS

We categorized 71 patients with suspected cerebral amyloid angiopathy markers (regardless of the presence of deep and cerebellar microbleeds) into 4 groups according to microbleed distribution: L (strictly lobar cerebral, n=33), L/LCbll (strictly lobar cerebral and strictly lobar cerebellar microbleeds, n=13), L/Cbll/D (lobar, cerebellar, and deep microbleeds, n=17), and L/D (lobar and deep, n=8). We additionally categorized patients with cerebellar microbleeds into 2 groups according to dentate nucleus involvement: strictly lobar cerebellar (n=16) and dentate (n=14). We then compared clinical characteristics, Aβ (amyloid-β) positivity on PET (positron emission tomography), magnetic resonance imaging cerebral amyloid angiopathy markers, and cerebral small vessel disease burden among groups.

RESULTS

The frequency of Aβ positivity was higher in the L and L/LCbll groups (81.8% and 84.6%) than in the L/Cbll/D and L/D groups (37.5% and 29.4%; P<0.001), while lacune numbers were lower in the L and L/LCbll groups (1.7±3.3 and 1.7±2.6) than in the L/Cbll/D and L/D groups (8.0±10.3 and 13.4±17.7, P=0.001). The L/LCbll group had more lobar cerebral microbleeds than the L group (93.2±121.8 versus 38.0±40.8, P=0.047). The lobar cerebellar group had a higher Aβ positivity (75% versus 28.6%, P=0.011) and lower lacune number (2.3±3.7 versus 8.6±1.2, P=0.041) than the dentate group.

CONCLUSIONS

Strictly lobar cerebral and cerebellar microbleeds are related to cerebral amyloid angiopathy, whereas any combination of concurrent lobar and deep microbleeds suggest hypertensive angiopathy regardless of cerebral or cerebellar compartments.

Prediction of amyloid β PET positivity using machine learning in patients with suspected cerebral amyloid angiopathy markers

Amyloid-β(Aβ) PET positivity in patients with suspected cerebral amyloid angiopathy (CAA) MRI markers is predictive of a worse cognitive trajectory, and it provides insights into the underlying vascular pathology (CAA vs. hypertensive angiopathy) to facilitate prognostic prediction and appropriate treatment decisions. In this study, we applied two interpretable machine learning algorithms, gradient boosting machine (GBM) and random forest (RF), to predict Aβ PET positivity in patients with CAA MRI markers. In the GBM algorithm, the number of lobar cerebral microbleeds (CMBs), deep CMBs, lacunes, CMBs in dentate nuclei, and age were ranked as the most influential to predict Aβ positivity. In the RF algorithm, the absence of diabetes was additionally chosen. Cut-off values of the above variables predictive of Aβ positivity were as follows: (1) the number of lobar CMBs > 16.4(GBM)/14.3(RF), (2) no deep CMBs(GBM/RF), (3) the number of lacunes > 7.4(GBM/RF), (4) age > 74.3(GBM)/64(RF), (5) no CMBs in dentate nucleus(GBM/RF). The classification performances based on the area under the receiver operating characteristic curve were 0.83 in GBM and 0.80 in RF. Our study demonstrates the utility of interpretable machine learning in the clinical setting by quantifying the relative importance and cutoff values of predictive variables for Aβ positivity in patients with suspected CAA markers.

Statins and Risk of Intracerebral Hemorrhage in Individuals With a History of Stroke

Background and Purpose—

It has been suggested that statins increase the risk of intracerebral hemorrhage in individuals with a history of stroke, which has led to a precautionary principle of avoiding statins in patients with prior intracerebral hemorrhage. However, such prescribing reticence may be unfounded and potentially harmful when considering the well-established benefits of statins. This study is so far the largest to explore the statin-associated risk of intracerebral hemorrhage in individuals with prior stroke.

Methods—

We conducted a population-based, propensity score–matched cohort study using information from Danish national registers. We included all individuals initiating statin treatment after a first-time stroke diagnosis (intracerebral hemorrhage, N=2728 or ischemic stroke, N=52 964) during 2002 to 2016. For up to 10 years of follow-up, they were compared with a 1:5 propensity score–matched group of statin nonusers with the same type of first-time stroke. The difference between groups was measured by adjusted hazard ratios for intracerebral hemorrhage calculated by type of first-time stroke as a function of time since statin initiation.

Results—

Within the study period, 118 new intracerebral hemorrhages occurred among statin users with prior intracerebral hemorrhage and 319 new intracerebral hemorrhages in users with prior ischemic stroke. The risk of intracerebral hemorrhage was similar for statin users and nonusers when evaluated among those with prior intracerebral hemorrhage, and it was reduced by half in those with prior ischemic stroke. These findings were consistent over time since statin initiation and could not be explained by concomitant initiation of other medications, by dilution of treatment effect (due to changes in exposure status over time), or by healthy initiator bias.

Conclusions—

This large study found no evidence that statins increase the risk of intracerebral hemorrhage in individuals with prior stroke; perhaps the risk is even lower in the subgroup of individuals with prior ischemic stroke.

Statins for neuroprotection in spontaneous intracerebral hemorrhage

Statins, a common drug class for treatment of dyslipidemia, may be neuroprotective for spontaneous intracerebral hemorrhage (ICH) by targeting secondary brain injury pathways in the surrounding brain parenchyma. Statin-mediated neuroprotection may stem from downregulation of mevalonate and its derivatives, targeting key cell signaling pathways that control proliferation, adhesion, migration, cytokine production, and reactive oxygen species generation. Preclinical studies have consistently demonstrated the neuroprotective and recovery enhancement effects of statins, including improved neurologic function, reduced cerebral edema, increased angiogenesis and neurogenesis, accelerated hematoma clearance, and decreased inflammatory cell infiltration. Retrospective clinical studies have reported reduced perihematomal edema, lower mortality rates, and improved functional outcomes in patients who were taking statins before ICH. Several clinical studies have also observed lower mortality rates and improved functional outcomes in patients who were continued or initiated on statins after ICH. Subgroup analysis of a previous randomized trial has raised concerns of a potentially elevated risk of recurrent ICH in patients with previous hemorrhagic stroke who are administered statins. However, most statin trials failed to show an association between statin use and increased hemorrhagic stroke risk. Variable statin dosing, statin use in the pre-ICH setting, and selection biases have limited rigorous investigation of the effects of statins on post-ICH outcomes. Future prospective trials are needed to investigate the association between statin use and outcomes in ICH.

Treatment Approaches to Lacunar Stroke

Lacunar strokes are appropriately named for their ability to cavitate and form ponds or "little lakes" (Latin: lacune -ae meaning pond or pit is a diminutive form of lacus meaning lake). They account for a substantial proportion of both symptomatic and asymptomatic ischemic strokes. In recent years, there have been several advances in the management of large vessel occlusions. New therapies such as non-vitamin K antagonist oral anticoagulants and left atrial appendage closure have recently been developed to improve stroke prevention in atrial fibrillation; however, the treatment of small vessel disease-related strokes lags frustratingly behind. Since Fisher characterized the lacunar syndromes and associated infarcts in the late 1960s, there have been no therapies specifically targeting lacunar stroke. Unfortunately, many therapeutic agents used for the treatment of ischemic stroke in general offer only a modest benefit in reducing recurrent stroke while adding to the risk of intracerebral hemorrhage and systemic bleeding. Escalation of antithrombotic treatments beyond standard single antiplatelet agents has not been effective in long-term lacunar stroke prevention efforts, unequivocally increasing intracerebral hemorrhage risk without providing a significant benefit. In this review, we critically review the available treatments for lacunar stroke based on evidence from clinical trials. For several of the major drugs, we summarize the adverse effects in the context of this unique patient population. We also discuss the role of neuroprotective therapies and neural repair strategies as they may relate to recovery from lacunar stroke.

Statins and Risk of Intracerebral Haemorrhage in a Stroke-Free Population: A Nationwide Danish Propensity Score Matched Cohort Study

BACKGROUND

Statins may increase the risk of intracerebral haemorrhage (ICH) in individuals with previous stroke. It remains unclear whether this applies to individuals with no history of stroke. This study is the first to explore the statin-associated risk of ICH in stroke-free individuals while considering the timing of statin initiation.

METHODS

We conducted a population-based, propensity score matched cohort study using information from five Danish national registers. We included all stroke-free individuals initiating statins in 2004-2013 and a propensity score matched group of non-users. Adjusted hazard ratios (aHRs) for ICH risk among statin users compared to non-users were calculated as a function of time since statin initiation.

FINDINGS

519,894 stroke-free individuals initiating statins and their 1:5 matched stroke-free reference subjects were included and followed for up to ten years. During this period, 1409 ICHs occurred in statin users. Statin users had an overall aHR of 0.85 (95% confidence interval: 0.80-0.90) compared to non-users, but this risk was modified by time since statin initiation. Statin users and non-users had similar ICH risk during the first six months after statin initiation. Hereafter, statin users had a 22-35% lower risk throughout the study period.

INTERPRETATION

Statin users had lower ICH risk than non-users from six months after statin initiation. This finding could not be explained by healthy initiator bias or differences between users and non-users in terms of sociodemographic characteristics, comorbidity, or parallel treatment regimens. Our study suggests that statin use in stroke-free populations is associated with reduced ICH risk.

FUNDING

The Novo Nordisk Foundation.

Association of statin use with spontaneous intracerebral hemorrhage: A cohort study

OBJECTIVE

To examine the association between statin exposure in a dose-dependent manner and intracerebral hemorrhage (ICH) in a large nationwide study.

METHODS

The computerized database of the largest health care provider in Israel was used to identify diagnosed ICH among new users of statins, who started statin treatment between 2005 and 2010. We assessed a dose-response relationship between ICH and statins, using the average atorvastatin equivalent daily dose (AAEDD). Multivariable Cox proportional hazard regression models, adjusted for baseline disease risk score, were applied to estimate the hazard ratio of ICH.

RESULTS

Of the 345,531 included patients, 1,304 were diagnosed with ICH during a median follow-up of 9.5 years (interquartile range 7.6-11.0). Overall, 75.3% of patients had AAEDD <10 mg/d, 19.0% had AAEDD 0-19.9 mg/d, and 5.7% had AAEDD ≥20 mg/d. The corresponding proportions were 81.0%, 15.0%, 4.0% among ICH cases, and 75.3%, 19.0%, 5.7% among non-ICH cases. Compared to those with AAEDD <10 mg/d (reference), the adjusted hazard ratio (HR) for ICH was 0.68 (95% confidence interval [CI] 0.58-0.79) in those with AAEDD 10-19.9 mg/d, and 0.62 (0.47-0.81) in those with AAEDD ≥20 mg/d. Compared to the lowest baseline total cholesterol quartile, the adjusted HR for ICH was 0.71 (95% CI 0.62-0.82), 0.55 (0.47-0.64), and 0.57 (0.49-0.67) in those in the second, third, and highest quartiles, respectively. The results were similar and robust among highly persistent statin users and after controlling for the change in cholesterol level.

CONCLUSIONS

This study confirms that the risk of ICH decreases with increasing cholesterol levels, but suggests that statin use might be associated with decreased risk of ICH.

Updates on Prevention of Hemorrhagic and Lacunar Strokes

Intracerebral hemorrhage (ICH) and lacunar infarction (LI) are the major acute clinical manifestations of cerebral small vessel diseases (cSVDs). Hypertensive small vessel disease, cerebral amyloid angiopathy, and hereditary causes, such as Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), constitute the three common cSVD categories. Diagnosing the underlying vascular pathology in these patients is important because the risk and types of recurrent strokes show significant differences. Recent advances in our understanding of the cSVD-related radiological markers have improved our ability to stratify ICH risk in individual patients, which helps guide antithrombotic decisions. There are general good-practice measures for stroke prevention in patients with cSVD, such as optimal blood pressure and glycemic control, while individualized measures tailored for particular patients are often needed. Antithrombotic combinations and anticoagulants should be avoided in cSVD treatment, as they increase the risk of potentially fatal ICH without necessarily lowering LI risk in these patients. Even when indicated for a concurrent pathology, such as nonvalvular atrial fibrillation, nonpharmacological approaches should be considered in the presence of cSVD. More data are emerging regarding the presentation, clinical course, and diagnostic markers of hereditary cSVD, allowing accurate diagnosis, and therefore, guiding management of symptomatic patients. When suspicion for asymptomatic hereditary cSVD exists, the pros and cons of prescribing genetic testing should be discussed in detail in the absence of any curative treatment. Recent data regarding diagnosis, risk stratification, and specific preventive approaches for both sporadic and hereditary cSVDs are discussed in this review article.

Statins do not increase Markers of Cerebral Angiopathies in patients with Cardioembolic Stroke

We investigated whether pre-treatment with statins is associated with surrogate markers of amyloid and hypertensive angiopathies in patients who need to start long-term oral anticoagulation therapy. A prospective multicenter study of patients naive for oral anticoagulants, who had an acute cardioembolic stroke. MRI was performed at admission to evaluate microbleeds, leukoaraiosis and superficial siderosis. We collected data on the specific statin compound, the dose and the statin intensity. We performed bivariate analyses and a logistic regression to investigate variables associated with microbleeds. We studied 470 patients (age 77.5 ± 6.4 years, 43.7% were men), and 193 (41.1%) of them received prior treatment with a statin. Microbleeds were detected in 140 (29.8%), leukoaraiosis in 388 (82.5%) and superficial siderosis in 20 (4.3%) patients. The presence of microbleeds, leukoaraiosis or superficial siderosis was not related to pre-treatment with statins. Microbleeds were more frequent in patients with prior intracerebral hemorrhage (OR 9.7, 95% CI 1.06–90.9) and in those pre-treated antiplatelets (OR 1.66, 95% CI 1.09–2.53). Prior treatment with statins was not associated with markers of bleeding-prone cerebral angiopathies in patients with cardioembolic stroke. Therefore, previous statin treatment should not influence the decision to initiate or withhold oral anticoagulation if these neuroimaging markers are detected.

Mixed-location cerebral hemorrhage/microbleeds: Underlying microangiopathy and recurrence risk

OBJECTIVE

To assess the predominant type of cerebral small vessel disease (SVD) and recurrence risk in patients who present with a combination of lobar and deep intracerebral hemorrhage (ICH)/microbleed locations (mixed ICH).

METHODS

Of 391 consecutive patients with primary ICH enrolled in a prospective registry, 75 (19%) had mixed ICH. Their demographics, clinical/laboratory features, and SVD neuroimaging markers were compared to those of 191 patients with probable cerebral amyloid angiopathy (CAA-ICH) and 125 with hypertensive strictly deep microbleeds and ICH (HTN-ICH). ICH recurrence and case fatality were also analyzed.

RESULTS

Patients with mixed ICH showed a higher burden of vascular risk factors reflected by a higher rate of left ventricular hypertrophy, higher creatinine values, and more lacunes and severe basal ganglia (BG) enlarged perivascular spaces (EPVS) than patients with CAA-ICH (all p < 0.05). In multivariable models mixed ICH diagnosis was associated with higher creatinine levels (odds ratio [OR] 2.5, 95% confidence interval [CI] 1.2-5.0, p = 0.010), more lacunes (OR 3.4, 95% CI 1.7-6.8), and more severe BG EPVS (OR 5.8, 95% CI 1.7-19.7) than patients with CAA-ICH. Conversely, when patients with mixed ICH were compared to patients with HTN-ICH, they were independently associated with older age (OR 1.03, 95% CI 1.02-1.1), more lacunes (OR 2.4, 95% CI 1.1-5.3), and higher microbleed count (OR 1.6, 95% CI 1.3-2.0). Among 90-day survivors, adjusted case fatality rates were similar for all 3 categories. Annual risk of ICH recurrence was 5.1% for mixed ICH, higher than for HTN-ICH but lower than for CAA-ICH (1.6% and 10.4%, respectively).

CONCLUSIONS

Mixed ICH, commonly seen on MRI obtained during etiologic workup, appears to be driven mostly by vascular risk factors similar to HTN-ICH but demonstrates more severe parenchymal damage and higher ICH recurrence risk.

The increasing impact of cerebral amyloid angiopathy: essential new insights for clinical practice

Cerebral amyloid angiopathy (CAA) has never been more relevant. The last 5 years have seen a rapid increase in publications and research in the field, with the development of new biomarkers for the disease, thanks to advances in MRI, amyloid positron emission tomography and cerebrospinal fluid biomarker analysis. The inadvertent development of CAA-like pathology in patients treated with amyloid-beta immunotherapy for Alzheimer's disease has highlighted the importance of establishing how and why CAA develops; without this information, the use of these treatments may be unnecessarily restricted. Our understanding of the clinical and radiological spectrum of CAA has continued to evolve, and there are new insights into the independent impact that CAA has on cognition in the context of ageing and intracerebral haemorrhage, as well as in Alzheimer's and other dementias. While the association between CAA and lobar intracerebral haemorrhage (with its high recurrence risk) is now well recognised, a number of management dilemmas remain, particularly when considering the use of antithrombotics, anticoagulants and statins. The Boston criteria for CAA, in use in one form or another for the last 20 years, are now being reviewed to reflect these new wide-ranging clinical and radiological findings. This review aims to provide a 5-year update on these recent advances, as well as a look towards future directions for CAA research and clinical practice.

Stroke Risk Factors, Genetics, and Prevention

Stroke is a heterogeneous syndrome, and determining risk factors and treatment depends on the specific pathogenesis of stroke. Risk factors for stroke can be categorized as modifiable and nonmodifiable. Age, sex, and race/ethnicity are nonmodifiable risk factors for both ischemic and hemorrhagic stroke, while hypertension, smoking, diet, and physical inactivity are among some of the more commonly reported modifiable risk factors. More recently described risk factors and triggers of stroke include inflammatory disorders, infection, pollution, and cardiac atrial disorders independent of atrial fibrillation. Single-gene disorders may cause rare, hereditary disorders for which stroke is a primary manifestation. Recent research also suggests that common and rare genetic polymorphisms can influence risk of more common causes of stroke, due to both other risk factors and specific stroke mechanisms, such as atrial fibrillation. Genetic factors, particularly those with environmental interactions, may be more modifiable than previously recognized. Stroke prevention has generally focused on modifiable risk factors. Lifestyle and behavioral modification, such as dietary changes or smoking cessation, not only reduces stroke risk, but also reduces the risk of other cardiovascular diseases. Other prevention strategies include identifying and treating medical conditions, such as hypertension and diabetes, that increase stroke risk. Recent research into risk factors and genetics of stroke has not only identified those at risk for stroke but also identified ways to target at-risk populations for stroke prevention.

Florbetapir-PET to diagnose cerebral amyloid angiopathy: A prospective study

OBJECTIVE

We hypothesized that florbetapir, a Food and Drug Administration-approved PET tracer, could distinguish cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) from hypertensive ICH (HTN-ICH).

METHODS

We prospectively enrolled survivors of primary ICH related to probable CAA (per Boston Criteria, n = 10) and HTN-ICH (n = 9) without dementia. All patients underwent florbetapir-PET and multimodal MRI, and patients with CAA had additional Pittsburgh compound B (PiB) PET. Amyloid burden was assessed quantitatively (standard uptake value ratio [SUVR]) and visually classified as positive or negative.

RESULTS

The CAA and HTN-ICH groups had similar age (66.9 vs 67.1), sex, and leukoaraiosis volumes (31 vs 30 mL, all p > 0.8). Florbetapir uptake and PiB retention strongly correlated in patients with CAA both globally within cerebral cortex (r = 0.96, p < 0.001) and regionally in lobar cortices (all r > 0.8, all p ≤ 0.01). Mean global cortical florbetapir uptake was substantially higher in CAA than HTN-ICH (SUVR: 1.41 ± 0.17 vs 1.15 ± 0.08, p = 0.001), as was mean occipital SUVR (1.44 ± 0.12 vs 1.17 ± 0.08, p < 0.001), even after correcting for global SUVR (p = 0.03). Visual rating for positive/negative florbetapir demonstrated perfect interrater agreement (k = 1) and was positive for all 10 patients with CAA vs 1 of 9 HTN-ICH patients (sensitivity 100%, specificity 89%).

CONCLUSIONS

Florbetapir appears to label vascular amyloid in patients with CAA-related ICH. The approved florbetapir binary visual reading method can have diagnostic value in appropriate clinical settings.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that florbetapir-PET provides a sensitivity of 100% (95% confidence interval [CI] 66%-100%) and specificity of 89% (95% CI 51%-99%) for determination of probable CAA among cognitively normal patients.

Diagnosis and Management of Acute Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the deadliest type of stroke and up to half of patients die in hospital. Blood pressure management, coagulopathy reversal, and intracranial pressure control are the mainstays of acute ICH treatment. Prevention of hematoma expansion and minimally invasive hematoma evacuation are promising therapeutic strategies under investigation. This article provides an updated review on ICH diagnosis and management in the emergency department.

Risk Profile of Symptomatic Lacunar Stroke Versus Nonlobar Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Although lacunar stroke (LS) and deep intracerebral hemorrhage (dICH) represent acute manifestations of the same pathological process involving cerebral small vessels (small vessel disease), it remains unclear what factors predispose to one phenotype rather than the other at individual level.

METHODS

Consecutive patients with either acute symptomatic LS or dICH were prospectively enrolled as part of a multicenter Italian study. We compared the risk factor profile of the 2 subgroups using multivariable logistic regression.

RESULTS

During a time course of 9.5 years, 1931 subjects (1434 LS and 497 dICH; mean age, 71.3±13.3 years; males, 55.5%) qualified for the analysis. Current smoking was associated with LS (odds ratio [OR], 2.17; P<0.001). Conversely, dICH cases were more likely to be hypertensive (OR, 1.87; P<0.001), excessive alcohol consumers (OR, 1.70; P=0.001), and more frequently under treatment with warfarin (OR, 2.05; P=0.010) and statins (OR, 3.10; P<0.001). Hypercholesterolemia, diabetes mellitus, and antiplatelet treatment were not associated with a specific small vessel disease manifestation.

CONCLUSIONS

The risk factor profile of dICH differs from that associated with LS. This might be used for disease risk stratification at individual level.

Animal models of spontaneous intracerebral hemorrhage

OBJECTIVES

Intracerebral hemorrhage (ICH) is a type of stroke that results in significant mortality and morbidity. Currently there is no definitive treatment for this disease. The paucity of animal models that reflect the heterogeneity of this spontaneous human disease could be the reason.

METHODS

In this review, we searched the literature for animal models of spontaneous ICH and found eight relevant papers.

RESULTS

Two were related to hypertension and six were related to cerebral amyloid angiopathy (CAA). One model used double transgenic mice overexpressing human renin and angiotensinogen which caused the mice to be hypertensive. Induction of ICH, however required addition of a high salt diet and nitric oxide synthase inhibition. Another mouse model of hypertension employed subcutaneous angiotensin II infusion and nitric oxide synthase inhibition plus acute injections of angiotensin to further elevate blood pressure. Five CAA models were in transgenic mice overexpressing amyloid precursor protein. One relied on the natural development of CAA in squirrel monkeys.

CONCLUSIONS

While all of the spontaneous ICH models have some advantages, the disadvantages include the sporadic time of onset of ICH and variability in size and location of ICH. Since there are no known efficacious treatments for ICH, it is not known if findings in the animal models will find treatments that are effective in humans.