Number of Cerebral Microbleeds and Risk of Intracerebral Hemorrhage After Intravenous Thrombolysis

Management of intracerebral hemorrhage--use of statins

Intracerebral hemorrhage (ICH) is a neurologic injury resulting in significant morbidity and mortality. Statins play a significant role in primary and secondary prevention of cardiovascular and cerebrovascular ischemic events. Despite clear benefits of statins in ischemic stroke, post hoc analyses of some studies suggest there may be a link between statin therapy and development of ICH. Direct pharmacologic effects of decreased serum levels of total cholesterol and low-density lipoproteins in conjunction with pleiotropic effects are thought to be linked to this possible increase in ICH risk. In the face of the potential of statins to increase the risk of ICH, recent evidence suggests that statins may also have beneficial effects on patient outcomes when continued or initiated following an ICH. This discordance in findings and the overall lack of well-designed prospective clinical trials increase the complexity of clinical decision making when utilizing statin therapy in patients with, or at risk for, ICH. This review evaluates the pharmacologic effects of statin therapy and describes how these effects translate to both risks and benefits in ICH. The current literature regarding the effects of statin therapy on clinical outcomes in ICH is evaluated to help guide clinicians with decisions regarding initiation, continuation, or discontinuation of statin therapy in patients with ICH.

An Up-to-Date Review on Cerebral Microbleeds

BACKGROUND

Cerebral microbleeds (CMBs) are small cerebrovascular lesions. More and more CMBs have been found in patients with ischemic stroke, dementia, and cerebral amyloid angiopathy, as well as some normal elderly populations. The objective of this study is to summarize the main risk factor, impairment, and therapy of CMBs.

METHODS

We searched and scanned all the literature with the keyword "cerebral microbleeds" or "CMBs" in the database of PubMed and Elsevier.

RESULTS

The risks factors for CMBs are complicated, including those that cause large-vessel disease, such as hypertension and old age, and those that cause small-vessel disease, such as amyloid deposits, endothelial lesions, and atrial fibrillation. Moreover, drugs and therapies used to treat cerebrovascular diseases such as statin, intravenous thrombolysis, and coumarin may also increase risk of CMBs. The relationship between antiplatelet treatment and CMBs is now unclear. Gene polymorphisms have been considered to be associated with CMBs. Gene mutations involving collagen type IV alpha 1 and collagen type IV alpha 2, sortilin-related receptor gene, forkhead box C1, and paired-like homeodomain 2 were reported to affect CMBs with the modification of corresponding proteins and functions. The cognition impairment caused by CMBs draws great attention. White matter deterioration is the possible answer. However, different studies could not reach the same conclusion on the damage of cognition of CMBs.

CONCLUSIONS

Further research is needed to provide effectual therapeutic proposals for CMBs, which differ from the treatment for large-artery disease and dementia.

Lower Serum Caveolin-1 Is Associated with Cerebral Microbleeds in Patients with Acute Ischemic Stroke

Caveolin-1 (Cav-1) plays pivotal roles in the endothelial damage following stroke. The present study aimed to investigate whether serum Cav-1 level is associated with the presence of cerebral small vessel disease (cSVD) in patients with acute ischemic stroke. To this end, 156 patients were consecutively enrolled. Cranial magnetic resonance imaging was analyzed to determine the surrogates of cSVD, including cerebral microbleeds (CMBs), silent lacunar infarcts (SLIs), and white matter hyperintensities (WMHs). After adjusting for potential confounders, patients with low Cav-1 level had a higher risk of CMBs than patients with high Cav-1 level (OR: 4.05, 95% CI: 1.77-9.30). However, there was no relationship between Cav-1 and the presence of SLIs or WMHs. When CMBs were stratified by location and number, a similar association was found in patients with deep or infratentorial CMBs (OR: 4.04, 95% CI: 1.59-10.25) and with multiple CMBs (OR: 3.18, 95% CI: 1.16-8.72). These results suggest lower serum Cav-1 levels may be associated with CMBs, especially those that are multiple and located in deep brain or infratentorial structures, in patients with acute ischemic stroke. Cav-1 may be involved in the pathophysiology of CMBs, and may act as a potential target for treating cSVD.

Cerebral microbleeds in idiopathic normal pressure hydrocephalus

Background

A vascular disease could be involved in pathophysiology of normal pressure hydrocephalus (INPH). If so, there should be an association between INPH and cerebral microbleeds (CMB). This study aims to analyze if CMB are associated with INPH.

Methods

In this case-control study we included 14 patients with INPH (mean age 76 years, 60 % female) and 41 healthy controls (HeCo; mean age 71 years, 60 % female). All were investigated with magnetic resonance imaging (MRI) using a T2*-sequence. The MRI exams were reviewed by two neuroradiologists for the presence of CMBs; the prevalence of findings of two or more CMBs was compared between INPH group and control group. After investigation, INPH patients underwent shunt surgery.

Results

Two or more CMB were detected more frequently in the INPH group compared to HeCo (n = 6, 43 % vs. n = 4, 10 %; p = 0.01). Among the participants where MRI revealed CMB, the number of CMB was higher among the INPH patients than the HeCo (median 8; IQR 2-34 vs. median 1; IQR 1–2; p = 0.005).

Conclusions

This study supports a vascular component to the pathophysiology of INPH.

High Prevalence of Cerebral Microbleeds in Inner City Young Stroke Patients

BACKGROUND

Data on cerebral microbleeds (CMBs) in younger populations are lacking, particularly in young stroke patients. We sought to characterize CMBs in an inner city cohort of young adults with stroke.

METHODS

CMB presence, count, and topography were assessed on magnetic resonance imaging (MRI) scans of 104 young stroke patients (≤49 years) presenting to Boston Medical Center between January 2006 and February 2010. Subsequent MRIs were assessed for the occurrence of new microbleeds in 29 patients. We performed cross-sectional analysis comparing baseline characteristics between patients with and without microbleeds, and between predefined microbleed burden and topography categories. We performed additional analysis to assess the determinants of new microbleeds on repeat MRI.

RESULTS

Microbleeds were present in 17% of the sample. Male sex (odds ratio [OR] 5.7, 95% confidence interval [CI] 1.0-32.6, P = .049), hypertension (OR 6.2, 95% CI 1.2-32, P = .03), moderate-severe white matter hyperintensities on MRI (OR 5.8, 95% CI 1.6-29.0, P = .01), and intracerebral hemorrhage (ICH; OR 5.0, 95% CI 1.2-20, P = .03) were over-represented in patients with microbleeds. Patients who developed new microbleeds on repeat MRI (14%) had higher microbleed counts on baseline MRI (50% versus 0% ≥ 3 CMBs, P = .02), history of illicit drug use (75% versus 24%, P = .08), positive serum toxicology for cocaine (67% versus 13%, P = .11), ICH as their presenting stroke subtype (50% versus 8%, P = .08), and over-representation of moderate-severe white matter hyperintensities (75% versus 20%, P = .05).

CONCLUSIONS

Results from this inner city cohort suggest that microbleeds are prevalent in young stroke patients and are largely associated with modifiable risk factors.

Spot Sign in Acute Intracerebral Hemorrhage in Dynamic T1-Weighted Magnetic Resonance Imaging

BACKGROUND AND PURPOSE

In computed tomographic imaging of acute intracerebral hemorrhage spot sign on computed tomographic angiography has been established as a marker for hematoma expansion and poor clinical outcome. Although, magnetic resonance imaging (MRI) can accurately visualize acute intracerebral hemorrhage, a corresponding MRI marker is lacking to date.

METHODS

We prospectively examined 50 consecutive patients with acute intracerebral hemorrhage within 24 hours of symptom onset. The MRI protocol consisted of a standard stroke protocol and dynamic contrast-enhanced T1-weighted imaging with a time resolution of 7.07 s/batch. Stroke scores were assessed at admission and at time of discharge. Volume measurements of hematoma size and spot sign were performed with MRIcron.

RESULTS

Contrast extravasation within sites of the hemorrhage (MRI spot sign) was seen in 46% of the patients. Patients with an MRI spot sign had a significantly shorter time to imaging than those without (P<0.001). The clinical outcome measured by the modified Rankin Scale was significantly worse in patients with spot sign compared with those without (P≤0.001). Hematoma expansion was observed in the spot sign group compared with the nonspot sign group, although the differences were not significant.

CONCLUSIONS

Spot sign can be detected using MRI on postcontrast T1-weighted and dynamic T1-weighted images. It is associated with worse clinical outcome. The time course of contrast extravasation in dynamic T1 images indicates that these spots represent ongoing bleeding.

Cerebral microbleeds and postthrombolysis intracerebral hemorrhage risk Updated meta-analysis

OBJECTIVE

We performed a systematic review and meta-analysis to assess whether the presence of cerebral microbleeds (CMBs) on pretreatment MRI scans of patients with acute ischemic stroke treated with thrombolysis is associated with an increased risk of symptomatic intracerebral hemorrhage (ICH).

METHODS

We searched PubMed for relevant studies and calculated pooled odds ratios (ORs) for symptomatic ICH, using the Mantel–Haenszel fixed-effects method, among individuals with vs without CMBs on pretreatment MRI scans. To minimize potential bias, sensitivity analysis was performed including studies providing data on patients treated only with IV thrombolysis.

RESULTS

Ten eligible studies including 2,028 patients were pooled in meta-analysis. The overall prevalence of CMBs was 23.3%. Among patients with CMBs, 40 of 472 (8.5%; 95%confidence interval [CI]: 6.1%–11.4%) experienced a symptomatic ICH after thrombolysis compared with 61 of 1,556 patients (3.9%; 95% CI: 3%–5%) without CMBs. The pooled OR of ICH across all studies was 2.26 (95%CI: 1.46–3.49; p , 0.0001). Eight studies, including 1,704 patients (n 5 401 with CMBs), provided data on patients treated with IV thrombolysis only; OR for the presence of CMBs and the development of symptomatic ICH was 2.87 (95%CI: 1.76–4.69; p , 0.0001).

CONCLUSIONS

Our meta-analysis of the available published data demonstrates an increased risk of symptomatic ICH after thrombolysis for acute ischemic stroke in patients with CMBs. However, we cannot fully exclude bias or confounding, so our results should be considered hypothesis generating. Detecting CMBs should not prevent thrombolytic treatment based on present evidence. Further analyses, taking into account CMB number and location, as well as measures of functional outcome, are needed.

Clinical Outcome in Acute Ischemic Stroke Patients With Microbleeds After Thrombolytic Therapy: A Meta-Analysis

It remains unclear whether preexisting cerebral microbleeds (CMBs) increase the risks of worse functional outcome after thrombolytic therapy. We performed a systematic review and meta-analysis to assess the risk of unfavorable outcome in patients with acute ischemic stroke and CMBs.We searched EMBASE, PubMed, and Web of Science for relevant studies assessing functional outcome in the patients with CMBs following thrombolytic therapy. Fixed-effects and random-effects models were performed.Five eligible studies including 1974 patients were pooled in meta-analysis. The prevalence of CMBs was 24.3%. The pooled analysis demonstrates odds ratio for preexisting CMBs and the achievement of favorable outcome to be 0.69 (95% CI 0.56-0.86; P = 0.001) with no evidence of statistical heterogeneity (I = 46.7%, P = 0.112).Our meta-analysis of available published data demonstrates an increased risk of worse functional outcome after thrombolytic therapy for acute ischemic stroke in patients with pre-existing CMBs. Future studies are needed to determine whether the risk outweigh the expected benefit of reperfusion therapies.

[Troponin elevation in ischemic stroke patients]

Cerebrovascular and cardiovascular diseases are major causes of death and disability worldwide. Ischemic stroke is a frequent complication in cardiac diseases and, vice versa, cardiac complications commonly cause early clinical worsening and death after stroke. In the emergency setting, cardiac biomarkers (preferably troponin, cTn) are measured frequently in patients presenting with acute ischemic stroke. The measurement of cTn is recommended by the guidelines for early management of patients with acute ischemic stroke from the American Heart Association. In case of pathologic cTn elevation, physicians are confronted with diagnostic and therapeutic uncertainties. Up-to-date recommendations on interpretation and consecutive actions remain ambiguous because cTn elevations may originate from causes other than acute coronary disease and because clinical signs and symptoms of acute coronary disease may be obscured by neurological deficits of the stroke. The application of modern, high-sensitive cTn assays that detect even minor cTn elevations has rather aggravated the dilemma of how to interpret this finding in patients with ischemic stroke.This article gives an overview on possible mechanisms of the frequently observed cTn elevation in ischemic stroke patients and offers help on interpretation and meaningful actions.

Extensive cerebral microbleeds predict parenchymal haemorrhage and poor outcome after intravenous thrombolysis

PURPOSE

Thrombolysis-related haemorrhagic transformation (HT) subtypes may have different prognostic implications. We aimed to analyse the impact of cerebral microbleeds (CMBs) burden on HT subtypes and outcome after intravenous thrombolysis.

METHODS

We retrospectively examined clinical and radiological data from 333 consecutive patients with acute ischaemic stroke who underwent susceptibility-weighted imaging before intravenous thrombolysis. Logistic regression analysis was used to determine the impact of CMBs on HT subtypes and neurological outcome.

RESULTS

We observed 596 CMBs in 119 (39.7%) patients on initial gradient-recalled echo scans. HT occurred in 88 (29.3%) patients, among which 62 were haemorrhagic infarction and 26 were parenchymal haemorrhage (PH). Logistic regression analysis indicated that the presence of extensive (≥ 3) CMBs was independently associated with PH (OR 6.704; 95% CI 2.054 to 21.883; p = 0.002) and poor clinical outcome (OR 2.281; 95% CI 1.022 to 5.093; p = 0.044).

CONCLUSIONS

The presence of extensive (≥ 3) CMBs increased the risk of PH 24 h after intravenous thrombolysis, and predicted poor clinical outcome independently.

Multimodal Diagnostic Imaging for Hyperacute Stroke

In April 2015, the American Roentgen Ray Society and the American Society of Neuroradiology cosponsored a unique program designed to evaluate the state of the art in the imaging work-up of acute stroke. This topic has grown in importance because of the recent randomized controlled trials demonstrating the clear efficacy of endovascular stroke treatment. The authors, who were participants in that symposium, will highlight the points of emphasis in this article.

Brain imaging in acute ischemic stroke—MRI or CT?

In acute stroke, imaging provides different technologies to demonstrate stroke subtype, tissue perfusion and vessel patency. In this review, we highlight recent clinical studies that are likely to guide therapeutic decisions. Clot length in computed tomography (CT) and clot burden in MR, imaging of leptomeningeal collaterals and indicators for active bleeding are illustrated. Imaging-based concepts for treatment of stroke at awakening and pre-hospital treatment in specialized ambulances offer new potentials to improve patient outcome.

Microbleed Status and 3-Month Outcome After Intravenous Thrombolysis in 717 Patients With Acute Ischemic Stroke

Background and Purpose—

Whether cerebral microbleeds (CMBs) detected on pretreatment magnetic resonance imaging increase the risks of symptomatic intracranial hemorrhage (sICH) and, most importantly, poor outcome in patients treated by intravenous thrombolysis for acute ischemic stroke is still debated. We assessed the effect of CMB presence and burden on 3-month modified Rankin Scale and sICH in a multicentric cohort.

Methods—

We analyzed prospectively collected data of consecutive patients solely treated by intravenous thrombolysis for acute ischemic stroke, in 2 centers where magnetic resonance imaging is the first-line pretreatment imaging. Neuroradiologists blinded to clinical data rated CMBs on T2* sequence using a validated scale. Logistic regressions were used to assess relationships between CMBs and 3-month modified Rankin Scale or sICH.

Results—

Among 717 patients, 150 (20.9%) had ≥1 CMBs. CMB burden was associated with worse modified Rankin Scale in univariable shift analysis (odds ratio, 1.07; 95% confidence interval, 1.00–1.15 per 1-CMB increase; P =0.049), but significance was lost after adjustment for age, hypertension, and atrial fibrillation (odds ratio, 1.03; 95% confidence interval, 0.96–1.11 per 1-CMB increase; P =0.37). Results remained nonsignificant when taking into account CMB location or presumed underlying vasculopathy. The incidence of sICH ranged from 3.8% to 9.1%, depending on the definition. Neither CMB presence, burden, location, nor presumed underlying vasculopathy was independently associated with sICH.

Conclusions—

Poor outcome or sICH was not associated with CMB presence or burden on pre–intravenous thrombolysis magnetic resonance imaging after adjustment for confounding factors. An individual patient data meta-analysis is needed to determine whether a subgroup of patients with CMBs carries an independent risk of poor outcome that might outweigh the expected benefit of intravenous thrombolysis.

Prognostic Impact of Cerebral Small Vessel Disease on Stroke Outcome

Cerebral small vessel disease (SVD), which includes white matter hyperintensities (WMHs), silent brain infarction (SBI), and cerebral microbleeds (CMBs), develops in a conjunction of cumulated injuries to cerebral microvascular beds, increased permeability of blood-brain barriers, and chronic oligemia. SVD is easily detected by routine neuroimaging modalities such as brain computed tomography or magnetic resonance imaging. Research has revealed that the presence of SVD markers may increase the risk of future vascular events as well as deteriorate functional recovery and neurocognitive trajectories after stroke, and such an association could also be applied to hemorrhagic stroke survivors. Currently, the specific mechanistic processes leading to the development and manifestation of SVD risk factors are unknown, and further studies with novel methodological tools are warranted. In this review, recent studies regarding the prognostic impact of WMHs, SBI, and CMBs on stroke survivors and briefly summarize the pathophysiological concepts underlying the manifestation of cerebral SVD.

Prevention and Management of Cerebral Small Vessel Disease

Lacunar infarcts/lacunes, white matter hyperintensities (WMH), and cerebral microbleeds (CMBs) are considered various manifestations of cerebral small vessel disease (SVD). Since the exact mechanisms of these manifestations differ, their associated risk factors differ. High blood pressure is the most consistent risk factor for all of these manifestations. However, a "J curve" phenomenon in terms of blood pressure probably exists for WMH. The association between cholesterol levels and lacunar infarcts/lacunes or WMH was less consistent and sometimes conflicting; a low cholesterol level probably increases the risk of CMBs. Homocysteinemia appears to be associated with WMH. It is noteworthy that the risk factors profile may also differ between different lacunar patterns and CMBs located at different parts of the brain. Thrombolysis, antihypertensives, and statins are used to treat patients with symptomatic lacunar infarction, just as in those with other stroke subtypes. However, it should be remembered that bleeding risks increase in patients with extensive WMH and CMBs after thrombolysis therapy. According to the Secondary Prevention of Small Subcortical Strokes trial results, a blood pressure reduction to <130 mmHg is recommended in patients with symptomatic lacunar infarction. However, an excessive blood pressure decrease may induce cognitive decline in older patients with extensive WMH. Dual antiplatelet therapy (aspirin plus clopidogrel) should be avoided because of the excessive risk of intracerebral hemorrhage. Although no particular antiplatelet is recommended, drugs such as cilostazol or triflusal may have advantages for patients with SVD since they are associated with less frequent bleeding complications than aspirin.

Mechanical thrombectomy for acute ischemic stroke with cerebral microbleeds

Background

The influence of cerebral microbleeds (CMBs) on post-thrombolytic hemorrhagic transformation (HT) in patients with acute ischemic stroke remains controversial.

Objective

To investigate the association of CMBs with HT and clinical outcomes among patients with large-vessel occlusion strokes treated with mechanical thrombectomy.

Methods

We analyzed patients with acute stroke treated with Merci Retriever, Penumbra system or stent-retriever devices. CMBs were identified on pretreatment T2-weighted, gradient-recall echo MRI. We analyzed the association of the presence, burden, and distribution of CMBs with HT, procedural complications, in-hospital mortality, and clinical outcome.

Results

CMBs were detected in 37 (18.0%) of 206 patients. Seventy-three foci of microbleeds were identified. Fourteen patients (6.8%) had ≥2 CMBs, only 1 patient had ≥5 CMBs. Strictly lobar CMBs were found in 12 patients, strictly deep CMBs in 12 patients, strictly infratentorial CMBs in 2 patients, and mixed CMBs in 11 patients. There were no significant differences between patients with CMBs and those without CMBs in the rates of overall HT (37.8% vs 45.6%), parenchymal hematoma (16.2% vs 19.5%), procedure-related vessel perforation (5.4% vs 7.1%), in-hospital mortality (16.2% vs 18.3%), and modified Rankin Scale score 0–3 at discharge. CMBs were not independently associated with HT or in-hospital mortality in patients treated with either thrombectomy or intravenous thrombolysis followed by thrombectomy.

Conclusions

Patients with CMBs are not at increased risk for HT and mortality following mechanical thrombectomy for acute stroke. Excluding such patients from mechanical thrombectomy is unwarranted. The risk of HT in patients with ≥5 CMBs requires further study.