The risk of subarachnoid and intracerebral hemorrhages in blacks as compared with whites

Update on the management of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease. Outcome after SAH is mainly determined by the initial severity of the hemorrhage. Neuroimaging, in particular computed tomography, and aneurysm repair techniques, such as coiling and clipping, as well as neurocritical care management, have improved during the last few years. The management of a patient with SAH should have an interdisciplinary approach with case discussions between the neurointensivist, interventionalist and the neurosurgeon. The patient should be treated in a specialized neurointensive care unit of a center with sufficient SAH case volume. Poor-grade patients can be observed for complications and delayed cerebral ischemia through continuous monitoring techniques in addition to transcranial Doppler ultrasonography such as continuous electroencephalography, brain tissue oxygenation, cerebral metabolism, cerebral blood flow and serial vascular imaging. Neurocritical care should focus on neuromonitoring for delayed cerebral ischemia, management of hydrocephalus, seizures and intracranial hypertension, as well as of medical complications such as hyperglycemia, fever and anemia.

Epidemiology and genetics of intracranial aneurysms

Intracranial aneurysms are acquired lesions (5-10% of the population), a fraction of which rupture leading to subarachnoid hemorrhage with devastating consequences. Until now, the exact etiology of intracranial aneurysms formation remains unclear. The low incidence of subarachnoid hemorrhage in comparison with the prevalence of unruptured IAs suggests that the vast majority of intracranial aneurysms do not rupture and that identifying those at highest risk is important in defining the optimal management. The most important factors predicting rupture are aneurysm size and site. In addition to ambiental factors (smoking, excessive alcohol consumption and hypertension), epidemiological studies have demonstrated a familiar influence contributing to the pathogenesis of intracranial aneurysms, with increased frequency in first- and second-degree relatives of people with subarachnoid hemorrhage. In comparison to sporadic aneurysms, familial aneurysms tend to be larger, more often located at the middle cerebral artery, and more likely to be multiple. Other than familiar occurrence, there are several heritable conditions associated with intracranial aneurysm formation, including autosomal dominant polycystic kidney disease, neurofibromatosis type I, Marfan syndrome, multiple endocrine neoplasia type I, pseudoxanthoma elasticum, hereditary hemorrhagic telangiectasia, and Ehlers-Danlos syndrome type II and IV. The familial occurrence and the association with heritable conditions indicate that genetic factors may play a role in the development of intracranial aneurysms. Genome-wide linkage studies in families and sib pairs with intracranial aneurysms have identified several loci on chromosomes showing suggestive evidence of linkage, particularly on chromosomes 1p34.3-p36.13, 7q11, 19q13.3, and Xp22. For the loci on 1p34.3-p36.13 and 7q11, a moderate positive association with positional candidate genes has been demonstrated (perlecan gene, elastin gene, collagen type 1 A2 gene). Moreover, 3 of the polymorphisms analyzed in 2 genes (endothelial nitric oxide synthase T786C, interleukin-6 G572C, and interleukin-6 G174C) were found to be significantly associated with ruptured/unruptured aneurysms: the endothelial nitric oxide synthase gene single-nucleotide polymorphisms increased the risk, while IL-6 G174C seemed protective. More recently, two genomic loci (endothelin receptor A and cyclin-dependent kinase inhibitor 2BAS) have been found to be significantly associated with intracranial aneurysms in the Japanese population; endothelin-1 is a potent vasoconstrictor produced by the endothelial cells. Until now, there are no diagnostic tests for specific genetic risk factors to identify patients who are at a high risk of developing intracranial aneurysms. Knowledge of the genetic determinants may be useful in order to allow clues on stopping aneurysm formation and obtain diagnostic tools for identifying individuals at increased risk. Further multicenter studies have to be carried out.

Cerebral vasospasm pharmacological treatment: an update

Aneurysmal subarachnoid hemorrhage- (aSAH-) associated vasospasm constitutes a clinicopathological entity, in which reversible vasculopathy, impaired autoregulatory function, and hypovolemia take place, and lead to the reduction of cerebral perfusion and finally ischemia. Cerebral vasospasm begins most often on the third day after the ictal event and reaches the maximum on the 5th-7th postictal days. Several therapeutic modalities have been employed for preventing or reversing cerebral vasospasm. Triple "H" therapy, balloon and chemical angioplasty with superselective intra-arterial injection of vasodilators, administration of substances like magnesium sulfate, statins, fasudil hydrochloride, erythropoietin, endothelin-1 antagonists, nitric oxide progenitors, and sildenafil, are some of the therapeutic protocols, which are currently employed for managing patients with aSAH. Intense pathophysiological mechanism research has led to the identification of various mediators of cerebral vasospasm, such as endothelium-derived, vascular smooth muscle-derived, proinflammatory mediators, cytokines and adhesion molecules, stress-induced gene activation, and platelet-derived growth factors. Oral, intravenous, or intra-arterial administration of antagonists of these mediators has been suggested for treating patients suffering a-SAH vasospam. In our current study, we attempt to summate all the available pharmacological treatment modalities for managing vasospasm.

Carotid artery stenosis as a cause of stroke

BACKGROUND

Population-based studies have estimated that about 15% of ischemic strokes are caused by large-vessel cerebrovascular disease. We determined the types of large-vessel atherosclerosis responsible for ischemic strokes in a population-based stroke study.

METHODS

Patients with first-ever or recurrent ischemic stroke in the Greater Cincinnati area were identified during 2005 at all local hospitals. Study physicians assigned ischemic stroke subtypes. Overall event rates and incidence rates for first-ever events were calculated, and age-, race- and sex-adjusted to the 2000 US population.

RESULTS

There were 2,204 ischemic strokes, including 365 strokes of large-vessel subtype (16.6% of all ischemic strokes). Extracranial internal carotid artery (ICA) stenosis was associated with 8.0% of all ischemic strokes, while extracranial ICA occlusion and intracranial atherosclerosis were each associated with 3.5% of strokes. The annual rate of first-ever and recurrent stroke attributed to extracranial ICA was 13.4 (11.4-15.4) per 100,000 persons. We conservatively estimate that about 41,000 strokes may be attributed to extracranial ICA stenosis annually in the United States.

CONCLUSIONS

Large-vessel atherosclerosis is an important cause of stroke, with extracranial ICA stenosis being significantly more common than extracranial ICA occlusion or intracranial atherosclerotic disease.

Subarachnoid hemorrhage in Kashmir: Causes, risk factors, and outcome

Context:

Kashmir, a snow bound and mountain locked valley, is populated by about 7 million ethnic and non-migratory Kashmiris who have specific dietary and social habits than rest of the world. The neurological disorders are common in Kashmiri population.

Aims:

To study the prevalence and outcome of spontaneous intracranial subarachnoid hemorrhage (SAH) in Kashmir compared withother parts of the world.

Settings and Design:

A retrospective and hospital based study from 1982 to 2010 in the single and only Neurosurgical Centre of the State of Jammu and Kashmir.

Materials and Methods:

A hospital based study, in which, information concerning all Kashmiri patients was collected from the case sheets, patient files, discharge certificates, death certificates, and telephonic conversations with the help of Medical Records Department and Central Admission Register of Sher–i-Kashmir Institute of Medical Sciences, Kashmir India.

Statistical Analysis:

Analysis of variance and students T-test were used at occasions.

Results:

Incidence of SAH in Kashmiris is about 13/100,000 persons per year. SAH comprises 31.02% of total strokes and aneurysmal ruptures are cause of 54.35% SAHs. The female suffers 1.78 times more than the male. Total mortality of 36.60% was recorded against a good recovery of 14.99%. The familial SAHs and multiple aneurysms were also common. Intra-operative finding of larger aneurysmal size than recorded on pre-operative computed tomography (CT) angiogram of same patients was noteworthy. In 493 patients of SAH, the angiography revealed 705 aneurysms.

Conclusion:

Spontaneous intracranial subarachnoid hemorrhage, due to aneurysmal rupture, is common in Kashmir, with worst outcome. Food habits like “salt-tea twice a day”, group-smoking of wet tobacco like “Jejeer”, winter season, female gender, hypertension, and inhalation of “Kangri” smoke are special risk factorsof SAH, in Kashmiris. The plain CT brain and CT angiography are best diagnostic tools. The preventive measures for aneurysmal formation and rupture seems most promising management of future. The detachable endovascular aneurysmal occupying video assisted micro-camera capsules or plugs may be future treatment.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Dual-energy CT in the evaluation of intracerebral hemorrhage of unknown origin: differentiation between tumor bleeding and pure hemorrhage

BACKGROUND AND PURPOSE

Detection of underlying tumor in patients with unknown-origin acute ICH may be difficult because acute hematoma may mask enhancement of tumor on postcontrast CT. We intended to investigate the clinical utility of DECT in differentiating tumor bleeding from pure ICH.

MATERIALS AND METHODS

Using a dual-source CT scanner, we obtained TNC single-energy and postcontrast DECT scans for 56 patients with unknown-origin spontaneous ICH. From the 2 sets of postcontrast DECT images obtained with different tube energy, EA (equivalent to conventional postcontrast CT), VNC, color-coded iodine overlay, fusion images of iodine overlay and VNC images were produced. The diagnostic performances of fusion, EA, and combined EA and TNC images for detecting underlying tumors were compared.

RESULTS

Of the 56 patients, 17 had primary or metastatic tumors (18 lesions) and 39 had nontumorous ICH. The sensitivities of fusion, EA, and combined EA and TNC images for detecting brain tumors were 94.4%, 61.1%, and 66.7%, respectively, and their specificities were 97.4%, 92.3%, and 89.7%, respectively. The areas under the ROC curves were 0.964, 0.786, and 0.842, respectively. Overall, the diagnostic performance of fusion images was significantly superior to EA (P = .006) and combined EA and TNC (P = .011) images.

CONCLUSIONS

DECT may be useful in detecting underlying tumors in patients with unknown-origin ICH.

Mirror aneurysms: a reflection on natural history

OBJECT

Investigators conducting the International Study of Unruptured Intracranial Aneurysms, sponsored by the National Institutes of Health, sought to evaluate predictors of future hemorrhage in patients who had unruptured mirror aneurysms. These paired aneurysms in bilateral arterial positions mirror each other; their natural history is unknown.

METHODS

Centers in the US, Canada, and Europe enrolled patients for prospective assessment of unruptured intracranial aneurysms. Central radiological review confirmed the presence or absence of mirror aneurysms in patients without a history of prior subarachnoid hemorrhage (SAH) (Group 1). Outcome at 1 and 5 years and aneurysm characteristics are compared.

RESULTS

Of 3120 patients with aneurysms treated in 61 centers, 376 (12%) had mirror aneurysms, which are more common in women than men (82% [n = 308] vs 73% [n = 1992], respectively; p <0.001) and in patients with a family history of aneurysm or SAH (p <0.001). Compared with patients with nonmirror saccular aneurysms, a greater percentage of patients with mirror aneurysms had larger (>10 mm) aneurysms (mean maximum diameter 11.7 vs 10.4 mm, respectively; p <0.001). The most common distribution for mirror aneurysms was the middle cerebral artery (34% [126 patients]) followed by noncavernous internal carotid artery (32% [121]), posterior communicating artery (16% [60]), cavernous internal carotid artery (13% [48]), anterior cerebral artery/anterior communicating artery (3% [13]), and vertebrobasilar circulation (2% [8]). When these patients were compared with patients without mirror aneurysms, no statistically significant differences were found in age (mean age 54 years in both groups), blood pressure, smoking history, or cardiac disease. Aneurysm rupture rates were similar (3.0% for patients with mirror aneurysms vs 2.8% for those without).

CONCLUSIONS

Overall, patients with mirror aneurysms were more likely to be women, to report a family history of aneurysmal SAH, and to have larger aneurysms. The presence of a mirror aneurysm was not an independent predictor of future SAHs.

Therapeutic strategies in acute intracerebral hemorrhage

Intracerebral hemorrhage is a devastating disease, and no specific therapy has been proven to reduce mortality in a randomized controlled trial. However, management in a neuroscience intensive care unit does appear to improve outcomes, suggesting that many available therapies do in fact provide benefit. In the acute phase of intracerebral hemorrhage care, strategies aimed at minimizing ongoing bleeding include reversal of anticoagulation and modest blood pressure reduction. In addition, the monitoring and regulation of glucose levels, temperature, and, in selected cases, intracranial pressure are recommended by many groups. Selected patients may benefit from hematoma evacuation or external ventricular drainage. Ongoing clinical trials are examining aggressive blood pressure management, hemostatic therapy, platelet transfusion, stereotactic hematoma evacuation, and intraventricular thrombolysis. Finally, preventing recurrence of intracerebral hemorrhage is of pivotal importance, and tight blood pressure management is paramount.

Therapeutic potential of umbilical cord blood stem cells on brain damage of a model of stroke

INTRODUCTION

Human cord blood-derived stem cells are a rich source of stem cells as well as precursors. With regard to the researchers have focused on the therapeutic potential of stem cell in the neurological disease such as stroke, the aim of this study was the investiga-tion of the therapeutic effects of human cord blood-derived stem cells in cerebral ischemia on rat.

METHODS

This study was carried out on young rats. Firstly, to create a laboratory model of ischemic stroke, carotid artery of animals was occluded for 30 minutes. Then, umbilical cord blood cells were isolated and labeled using bromodeoxyuridine and 2×10(5) cells were injected into the experimental group via the tail vein. Rats with hypoxic condi-tions were used as a sham group. A group of animals did not receive any injection or sur-geries were used as a control.

RESULTS

Obtained results were evaluated based on behavioral responses and immunohistochemistry, with emphasis on areas of putamen and caudate nucleus in the control, sham and experimental groups. Our results indicated that behavioral recovery was observed in the experimental group compared to the either the sham or the control group. However, histological studies demonstrated a low percent of tissue injury in the experimental group in comparison with the sham group.

CONCLUSION

Stem cell transplantation is beneficial for the brain tissue reparation after hypoxic ischemic cell death.

Factors associated with severity on admission and in-hospital mortality after primary intracerebral hemorrhage in China

BACKGROUND AND PURPOSE

Of the stroke types, intracerebral hemorrhage is the most debilitating and fatal. The aim of the current study was to determine factors that influence the severity and in-hospital mortality after primary intracerebral hemorrhage.

METHODS

Data were collected retrospectively on 1268 patients with primary intracerebral hemorrhage admitted to stroke units at participating hospitals in Guangzhou between January 2005 and August 2008. Logistic regression analysis was used to determine factors associated with severity on admission and in-hospital mortality.

RESULTS

Of the 1268 patients, 20·4% were reported to have a severe stroke on admission, and the in-hospital mortality rate was 12·5%. Severity on admission was strongly associated with Glasgow Coma Scale score on admission (odds ratio = 0·89, 95% confidence interval 0·85-0·94) and hematoma location. Notably, basal ganglia hemorrhages were associated with increased severity (odds ratio = 1·40, 95% confidence interval 1·03-1·90), and cerebellar hemorrhages were associated with reduced severity (odds ratio = 0·29, 95% confidence interval 0·10-0·84). In-hospital mortality was not only correlated with Glasgow Coma Scale score on admission (odds ratio = 0·79, 95% confidence interval 0·74-0·84) and basal ganglia location (odds ratio = 0·47, 95% confidence interval 0·26-0·83), but also with dysnatremia (odds ratio = 1·91, 95% confidence interval 1·08-3·40) and comorbidities such as upper gastrointestinal hemorrhage (odds ratio = 2·28, 95% confidence interval 1·33-3·91), pneumonia (odds ratio = 3·50, 95% confidence interval 2·17-5·63), urinary incontinence (odds ratio = 2·22, 95% confidence interval 1·40-3·51), and renal dysfunction (odds ratio = 2·28, 95% confidence interval 1·42-3·65).

CONCLUSION

Glasgow Coma Scale score and hematoma locations were independently associated with severity on admission and in-hospital mortality after primary intracerebral hemorrhage. The study also highlights the deleterious effect of comorbidities on in-hospital mortality following primary intracerebral hemorrhage in China.

CT angiography spot sign predicts in-hospital mortality in patients with secondary intracerebral hemorrhage

BACKGROUND AND OBJECTIVE

The presence of active contrast extravasation during CT angiography, the spot sign, is a potent predictor of in-hospital mortality in patients with primary intracerebral hemorrhage (ICH). However, its predictive value in patients with ICH due to a vascular abnormality, secondary ICH (SICH), is unknown. The aim of this study was to determine the clinical and radiological predictors of a spot sign and in-hospital mortality in patients with SICH.

METHODS

Two experienced readers independently reviewed CT angiograms performed on 215 consecutive patients presenting to the emergency department with SICH over a 10-year period to assess the presence of spot signs according to strict radiological criteria. Differences in reader interpretation were resolved by consensus. Medical records were reviewed for baseline clinical characteristics and in-hospital mortality. Univariate and multivariate logistic regression analyses were performed to determine the clinical and radiological predictors of a spot sign and in-hospital mortality in patients with SICH.

RESULTS

Spot signs were identified in 31 of 215 patients with SICH (14.4%), four of which were delayed spot signs (12.9%). Spot signs were most common in patients with arteriovenous fistulas (42%), Moyamoya (40%), elevated admission blood glucose (23%) and large intraventricular hemorrhage volumes (29%). Spot signs were most predictive of in-hospital mortality in patients with aneurysms of the anterior cerebral artery (100%) and anterior communicating artery (75%). In univariate analysis, the presence of a spot sign significantly increased the risk of in-hospital mortality in patients with SICH (38.7%, OR 2.2, 95% CI 1.0 to 4.9, p=0.0497). However, in multivariate logistic regression analysis the admission Glasgow Coma Scale was the only independent predictor of in-hospital mortality in patients with SICH (OR 2.8, 95% CI 1.6 to 5.1, p=0.0004).

CONCLUSION

The spot sign identifies patients with SICH at increased risk of in-hospital mortality. However, the admission Glasgow Coma Scale was the only independent predictor of in-hospital mortality in this cohort of patients with SICH.

Potential eligibility for recombinant tissue plasminogen activator therapy in children: a population-based study

Intravenous recombinant tissue plasminogen activator is an established therapy for adults with ischemic stroke. In this Greater Cincinnati/Northern Kentucky population-based study, 8% were eligible. However, no established therapy exists for children with acute ischemic stroke. Accordingly, investigators assessed rates of eligibility for recombinant tissue plasminogen activator therapy among children (<18 years of age) in the same population to aid planning of future clinical trials. The investigators identified 29 pediatric ischemic strokes during 3 separate study periods (1993-1994, 1999, and 2005) and determined potential eligibility for recombinant tissue plasminogen activator therapy based on 2007 American Heart Association guidelines for adults. Depending on how relative contraindications were considered, 1 to 3 cases (3%-10%) met eligibility criteria. On the basis of national pediatric stroke incidence rates extrapolated from our population, it is estimated that up to 178 children might be eligible for intravenous recombinant tissue plasminogen activator therapy annually in the United States. Thus, recruitment for clinical studies is likely to be challenging and requires a concerted multicenter effort.

Treatment targets in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) imparts a higher mortality and morbidity than ischemic stroke. The therapeutic interventions that are currently available focus mainly on supportive care and secondary prevention. There is a paucity of evidence to support any one acute intervention that improves functional outcome. This chapter highlights current treatment targets for ICH based on the pathophysiology of the disease.

Racial-ethnic disparities in stroke care: the American experience: a statement for healthcare professionals from the American Heart Association/American Stroke Association

PURPOSE

Our goal is to describe the effect of race and ethnicity on stroke epidemiology, personal beliefs, access to care, response to treatment, and participation in clinical research. In addition, we seek to determine the state of knowledge on the main factors that may explain disparities in stroke care, with the goal of identifying gaps in knowledge to guide future research. The intended audience includes physicians, nurses, other healthcare professionals, and policy makers.

METHODS

Members of the writing group were appointed by the American Heart Association Stroke Council Scientific Statement Oversight Committee and represent different areas of expertise in relation to racial-ethnic disparities in stroke care. The writing group reviewed the relevant literature, with an emphasis on reports published since 1972. The statement was approved by the writing group; the statement underwent peer review, then was approved by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

There are limitations in the definitions of racial and ethnic categories currently in use. For the purpose of this statement, we used the racial categories defined by the US federal government: white, black or African American, Asian, American Indian/Alaskan Native, and Native Hawaiian/other Pacific Islander. There are 2 ethnic categories: people of Hispanic/Latino origin or not of Hispanic/Latino origin. There are differences in the distribution of the burden of risk factors, stroke incidence and prevalence, and stroke mortality among different racial and ethnic groups. In addition, there are disparities in stroke care between minority groups compared with whites. These disparities include lack of awareness of stroke symptoms and signs and lack of knowledge about the need for urgent treatment and the causal role of risk factors. There are also differences in attitudes, beliefs, and compliance among minorities compared with whites. Differences in socioeconomic status and insurance coverage, mistrust of the healthcare system, the relatively limited number of providers who are members of minority groups, and system limitations may contribute to disparities in access to or quality of care, which in turn might result in different rates of stroke morbidity and mortality. Cultural and language barriers probably also contribute to some of these disparities. Minorities use emergency medical services systems less, are often delayed in arriving at the emergency department, have longer waiting times in the emergency department, and are less likely to receive thrombolysis for acute ischemic stroke. Although unmeasured factors may play a role in these delays, the presence of bias in the delivery of care cannot be excluded. Minorities have equal access to rehabilitation services, although they experience longer stays and have poorer functional status than whites. Minorities are inadequately treated with both primary and secondary stroke prevention strategies compared with whites. Sparse data exist on racial-ethnic disparities in access to surgical care after intracerebral hemorrhage and subarachnoid hemorrhage. Participation of minorities in clinical research is limited. Barriers to participation in clinical research include beliefs, lack of trust, and limited awareness. Race is a contentious topic in biomedical research because race is not proven to be a surrogate for genetic constitution.

CONCLUSIONS

There are limitations in the current definitions of race and ethnicity. Nevertheless, racial and ethnic disparities in stroke exist and include differences in the biological determinants of disease and disparities throughout the continuum of care, including access to and quality of care. Access to and participation in research is also limited among minority groups. Acknowledging the presence of disparities and understanding the factors that contribute to them are necessary first steps. More research is required to understand these differences and find solutions.

A new cerebral hemorrhage model in cynomolgus macaques created by injection of autologous anticoagulated blood into the brain

The aim of this study was to establish and validate a clinically relevant model of intracerebral hemorrhage (ICH) via injection of autologous blood into the brains of cynomolgus macaques (Macaca fascicularis). Eight male cynomolgus macaques received 1.5 mL of fresh anticoagulated autologous femoral artery blood into the inner side of the claustrum near the right basal ganglia under stereotactic guidance. Animals were evaluated with MRI and positron emission tomography (PET) scanning before and 24 hours after surgery and once per week thereafter. A neurological deficit scale was used to assess the animals on days 1, 2, 3, 7, 14, 21, and 28 after surgery. Animals showed focal neurological signs corresponding to the MRI-located hematoma. The behavioral impairment progressively ameliorated over time, but never fully resolved. The hematoma was absorbed over time but was still present 4 weeks after surgery, with persistent metabolic deficit detected using PET scanning. Histological examinations confirmed the in vivo findings. This ICH model in a non-human primate mimics human ICH in the basal ganglia and may be useful for assessing the safety and efficacy of neuroprotective agents.

Spontaneous intracerebral haemorrhage: a clinical review

This article provides a clinical overview of spontaneous intracerebral haemorrhage, focusing on clinical aspects of the aetiology, diagnosis and management (both in the emergency department and in a critical care environment) of this important and devastating condition.

Current and future treatment considerations in the management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a type of hemorrhagic stroke that can cause significant morbidity and mortality. Although guidelines have been published to help direct the care of these patients, there is insufficient quality literature regarding the medical and pharmacological management of patients with aSAH. Treatment is divided into 3 categories: supportive therapy, prevention of complications, and treatment of complications. There are numerous pharmacological therapies that are targeted at prevention and treatment of the neurological and medical complications that may arise. Rebleeding, hydrocephalus, cerebral vasospasm, and seizures are the most common neurological complications while the most common medical complications include hyponatremia, pulmonary edema, cardiac arrhythmias, neurogenic stunned myocardium, fever, anemia, infection, hyperglycemia, and venous thromboembolism. Risk factors, clinical presentation, diagnosis, pathophysiology, as well as initial management, prevention, and treatment of complications will be the focus of this discussion.

Surgical management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and often devastating condition that requires prompt neurosurgical evaluation and intervention. Modern management of aSAH involves a multidisciplinary team of subspecialists, including vascular neurosurgeons, neurocritical care specialists and, frequently, neurointerventional radiologists. This team is responsible for stabilizing the patient on presentation, diagnosing the offending ruptured aneurysm, securing the aneurysm, and managing the patient through a typically prolonged and complicated hospital course. Surgical intervention has remained a definitive treatment for ruptured cerebral aneurysms since the early 1900s. Over the subsequent decades, many innovations in microsurgical technique, adjuvant maneuvers, and intraoperative and perioperative medical therapies have advanced the care of patients with aSAH. This report focuses on the modern surgical management of patients with aSAH. Following a brief historical perspective on the origin of aneurysm surgery, the topics discussed include the timing of surgical intervention after aSAH, commonly used surgical approaches and craniotomies, fenestration of the lamina terminalis, intraoperative neurophysiological monitoring, intraoperative digital subtraction and fluorescent angiography, temporary clipping, deep hypothermic cardiopulmonary bypass, management of acute hydrocephalus, cerebral revascularization, and novel clip configurations and microsurgical techniques. Many of the topics highlighted in this report represent some of the more debated techniques in vascular neurosurgery. The popularity of such techniques is constantly evolving as new studies are performed and data about their utility become available.

Salt sensitivity and circadian rhythm of blood pressure: the keys to connect CKD with cardiovascular events

In healthy subjects, blood pressure (BP) drops by 10-20% during the night. Conversely, in patients with the salt-sensitive type of hypertension or chronic kidney disease, nighttime BP does not fall, resulting in an atypical pattern of circadian BP rhythm that does not dip. This pattern is referred to as the 'non-dipper' pattern. Loss of renal functional reserve, due to either reduced ultrafiltration capacity or enhanced tubular sodium reabsorption, induces the salt-sensitive type of hypertension. When salt intake is excessive in patients with salt-sensitive hypertension, the defect in sodium excretory capability becomes evident, resulting in elevated BP during the night. This nocturnal hypertension compensates for diminished natriuresis during the daytime and enhances pressure natriuresis during the night. Nocturnal hypertension and the non-dipper pattern of circadian BP rhythm cause cardiovascular events. When excess salt intake is loaded in patients who are in a salt-sensitive state, glomerular capillary pressure is also elevated, resulting in glomerular sclerosis and eventual renal failure. In this way, salt sensitivity and excess salt intake contribute to both cardiovascular and renal damage at the same time. We propose that salt sensitivity of BP and excess salt intake have important roles in the genesis of the cardiorenal connection. Salt sensitivity and circadian rhythm of BP are the keys to understanding the connections between cardiovascular and renal complications.

The genetics of sporadic ruptured and unruptured intracranial aneurysms: a genetic meta-analysis of 8 genes and 13 polymorphisms in approximately 20,000 individuals

Object

Intracranial aneurysms (IAs) are thought to have a multifactorial origin. The authors undertook a comprehensive meta-analysis on all genes investigated using a case-control model in ruptured (subarachnoid hemorrhage) and unruptured aneurysms.

Methods

Electronic databases were searched until and including July 2008 for any candidate gene studied in IA or subarachnoid hemorrhage using a case-control model. The ORs and 95% CIs were determined for each gene-disease association using fixed and random effect models.

Results

Thirty studies of 8 genes and 13 polymorphisms were analyzed among 19,961 individuals (6622 cases and 13,339 controls). Two genes and 3 polymorphisms were associated with IA. The eNOS gene T786C polymorphism (OR 1.24, 95% CI 1.0–1.54; p = 0.05) and IL-6 gene G572C polymorphism (OR 7.08, 95% CI 2.85–17.57; p < 0.0001) both showed a significant association with ruptured/unruptured IA. The IL-6/G174C polymorphism exerted a significant protective effect against IA (OR 0.49, 95% CI 0.25–0.95; p = 0.04). The other candidate genes investigated (ACE, endoglin, APOE, elastin, MMP-3, and SERPINA3) showed no significant associations.

Conclusions

There is a likely genetic basis to sporadic IAs. However, the evidence base is small when compared against other complex disorders.

Hemin toxicity: a preventable source of brain damage following hemorrhagic stroke

Hemorrhagic stroke is a common cause of permanent brain damage, with a significant amount of the damage occurring in the weeks following a stroke. This secondary damage is partly due to the toxic effects of hemin, a breakdown product of hemoglobin. The serum proteins hemopexin and albumin can bind hemin, but these natural defenses are insufficient to cope with the extremely high amounts of hemin (10 mM) that can potentially be liberated from hemoglobin in a hematoma. The present review discusses how hemin gets into brain cells, and examines the multiple routes through which hemin can be toxic. These include the release of redox-active iron, the depletion of cellular stores of NADPH and glutathione, the production of superoxide and hydroxyl radicals, and the peroxidation of membrane lipids. Important gaps are revealed in contemporary knowledge about the metabolism of hemin by brain cells, particularly regarding how hemin interacts with hydrogen peroxide. Strategies currently being developed for the reduction of hemin toxicity after hemorrhagic stroke include chelation therapy, antioxidant therapy and the modulation of heme oxygenase activity. Future strategies may be directed at preventing the uptake of hemin into brain cells to limit the opportunity for toxic interactions.

The putative heme transporter HCP1 is expressed in cultured astrocytes and contributes to the uptake of hemin

Hemin, which is toxic to brain cells, has been reported to be taken up by cultured astrocytes; however, the mechanism of uptake is currently unknown. The present study investigated the mechanism of hemin uptake by rat primary astrocyte cultures. In medium containing 10% fetal calf serum, cultured astrocytes failed to accumulate significant amounts of heme-iron, while in serum-free medium the accumulation of heme-iron was found to be time- and concentration-dependent. After 6 h of incubation with 24 muM hemin, cells contained 36.2 +/- 2.4 nmol heme-iron/mg protein, which was 21% of the applied hemin. These results suggest that the accumulation of hemin in astrocytes does not require serum proteins such as hemopexin. A potential mechanism of hemin uptake in astrocytes involves the heme carrier protein 1 (HCP1), which is reported to mediate hemin uptake into intestinal cells. RT-PCR analysis revealed that astrocyte cultures contained HCP1 mRNA, and immunocytochemical staining and Western blot analysis confirmed the expression of HCP1 protein in cultured astrocytes. The functionality of HCP1 in astrocytes was demonstrated by incubating cells with zinc protoporphyrin IX (ZnPPIX), which is known to be transported into cells via HCP1, and ZnPPIX autofluorescence was detected in HCP1-positive astrocytes. In addition, ZnPPIX was found to attenuate the accumulation of heme-iron by astrocytes. These results are the first to demonstrate that cultured astrocytes contain functional HCP1 and that this transporter contributes to hemin uptake by astrocytes. HCP1 may therefore provide a new target for reducing hemin-related toxicity in brain cells.

The spot sign score in primary intracerebral hemorrhage identifies patients at highest risk of in-hospital mortality and poor outcome among survivors

BACKGROUND AND PURPOSE

The spot sign score is a potent predictor of hematoma expansion in patients with primary intracerebral hemorrhage (ICH). We aim to determine the accuracy of this scoring system for the prediction of in-hospital mortality and poor outcome among survivors in patients with primary ICH.

METHODS

Three neuroradiologists retrospectively reviewed CT angiograms (CTAs) performed in 573 consecutive patients who presented to our Emergency Department with primary ICH over a 9-year period to determine the presence and scoring of spot signs according to strict criteria. Baseline ICH and intraventricular hemorrhage volumes were independently determined by computer-assisted volumetric analysis. Medical records were independently reviewed for baseline clinical characteristics and modified Rankin Scale (mRS) at hospital discharge and 3-month follow-up. Poor outcome among survivors was defined as a mRS > or =4 at 3-month follow-up.

RESULTS

We identified spot signs in 133 of 573 CTAs (23.2%), 11 of which were delayed spot signs (8.3%). The presence of any spot sign increased the risk of in-hospital mortality (55.6%, OR 4.0, 95% CI 2.6 to 5.9, P<0.0001) and poor outcome among survivors at 3-month follow-up (50.8%, OR 2.5, 95% CI 1.4 to 4.3, P<0.0014). The spot sign score successfully predicted an escalating risk of both outcome measures. In multivariate analysis, the spot sign score was an independent predictor of in-hospital mortality (OR 1.5, 95% CI 1.2 to 1.9, P<0.0002) and poor outcome among survivors at 3-month follow-up (OR 1.6, 95% CI 1.1 to 2.1, P<0.0065).

CONCLUSIONS

The spot sign score is an independent predictor of in-hospital mortality and poor outcome among survivors in primary ICH.

Role of gap junctions in early brain injury following subarachnoid hemorrhage

Gap junction inhibition has been demonstrated to reverse the vascular contraction that follows experimental subarachnoid hemorrhage. This study hypothesizes that the use of established gap junction inhibitors: octonal and carbenoxolone, to interrupt cell to cell communication will provide neuroprotection against early brain injury after SAH. The filament perforation model of SAH was performed in male Sprague-Dawley rats weighing between 300 and 380 g. Octanol (260.46 mg or 781.38 mg/kg), carbenoxolone (100 mg/kg), or vehicles were given via intraperitoneal injection 1 h after SAH. Neurologic deficits and cerebral apoptosis were assessed 24 and 72 h after SAH. In addition, Western blot analysis was performed to confirm the in vivo inhibition of CNS gap junctions. The administration of octanol and carbenoxolone both failed to attenuate the neurological deficits induced by SAH, and they did not reduce neuronal apoptosis. Additionally, carbenoloxone increased post SAH mortality and exacerbated SAH-induced apoptosis. Despite previous studies that show gap junction inhibitors reverse vasospasm following experimental SAH, they failed to improve clinical outcomes or provide neuroprotection in this study.

Racial differences in ischemic cerebrovascular disease

PURPOSE

To evaluate racial differences in extracranial carotid atherosclerosis and vascular risk factors in patients with symptomatic cerebrovascular disease.

BACKGROUND

There are conflicting data on racial differences in certain vascular risk factors and prevalence of large-vessel versus small-vessel disease in patients with stroke.

METHODS

We prospectively studied 211 consecutive patients admitted to our stroke service. There were 71 African-American, 114 Caucasian, 20 Hispanic, and 6 other patients. Extracranial vascular stenosis was assessed with a carotid duplex (CD) scan. Risk factors monitored included race, age, history of hypertension (HTN), diabetes mellitus (DM), prior stroke, hyperlipidemia, smoking, cardiac disease (congestive heart failure, atrial fibrillation), and family history of stroke. Cholesterol and triglyceride blood levels, and computed tomography/magnetic resonance imaging results were obtained in most cases.

RESULTS

Significant differences were found between Caucasians and African-Americans in several variables. Caucasians had more frequent hypertriglyceridemia and a higher rate of cardiac disease. African-Americans had more frequent lacunar infarcts. There was a trend toward decreased risk of CD scan abnormality, and more HTN and prior stroke in African-Americans. There were no differences in the presence of DM, both HTN and DM, abnormal cholesterol (including high- and low-density lipoprotein) values, and smoking history. Except for the difference in lacunar infarction, there were no differences in the type of stroke.

CONCLUSIONS

Our data indicate a greater risk of cardiac disease and hypertriglyceridemia in Caucasians with cerebrovascular disease. There was a trend for Caucasians to have more extracranial carotid disease, and a trend for African-Americans to have more hypertension and prior stroke, although the difference did not reach significance. Consistent with prior racial studies, we found African-Americans to have more lacunar strokes than Caucasians.

Cerebral inflammatory response and predictors of admission clinical grade after aneurysmal subarachnoid hemorrhage

Poor admission clinical grade is the most important determinant of outcome after aneurysmal subarachnoid hemorrhage (aSAH); however, little attention has been focused on independent predictors of poor admission clinical grade. We hypothesized that the cerebral inflammatory response initiated at the time of aneurysm rupture contributes to ultra-early brain injury and poor admission clinical grade. We sought to identify factors known to contribute to cerebral inflammation as well as markers of cerebral dysfunction that were associated with poor admission clinical grade. Between 1997 and 2008, 850 consecutive SAH patients were enrolled in our prospective database. Demographic data, physiological parameters, and location and volume of blood were recorded. After univariate analysis, significant variables were entered into a logistic regression model to identify significant associations with poor admission clinical grade (Hunt-Hess grade 4-5). Independent predictors of poor admission grade included a SAH sum score >15/30 (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.5-3.6), an intraventricular hemorrhage sum score >1/12 (OR 3.1, 95% CI 2.1-4.8), aneurysm size >10mm (OR 1.7, 95% CI 1.1-2.6), body temperature 38.3 degrees C (OR 2.5, 95% CI 1.1-5.4), and hyperglycemia >200mg/dL (OR 2.7, 95% CI 1.6-4.5). In a large, consecutive series of prospectively enrolled patients with SAH, the inflammatory response at the time of aneurysm rupture, as reflected by the volume and location of the hemoglobin burden, hyperthermia, and perturbed glucose metabolism, independently predicts poor admission Hunt-Hess grade. Strategies for mitigating the inflammatory response to aneurysmal rupture in the hyper-acute setting may improve the admission clinical grade, which may in turn improve outcomes.

Epidemiology of intracranial aneurysms of Mississippi: a 10-year (1997-2007) retrospective study

BACKGROUND

Despite massive efforts, progress so far has been modest in isolating the genetic determinants for intracranial aneurysm (IA). More detailed epidemiology data might be essential for successful genome-wide association study. Here, we aimed to investigate epidemiology and identify the key risk factors associated with the pathogenesis of IA in a large specific population.

METHODS

We investigated the epidemiology and analyzed the risk factors of IA pathogenesis by using an International Classification of Diseases, Ninth Revision database search of the patients treated at the University of Mississippi Medical Center, Jackson, MS, within the past 10-year period (1998-2007). All recruited patients were interviewed to assess multiple risk factors and comorbidities (hypertension, tobacco abuse, females sex, diabetes mellitus, coronary artery disease, coronary obstructive pulmonary disease, alcohol abuse, stroke, hyperlipidemia, illicit drug use, and family history).

RESULT

In this retrospective study, we identified several significant risk factors among well-defined human subjects. The 3 major risk factors identified for our IA population are hypertension, tobacco abuse, and female sex. However, African American race was not a significant risk factor in our study. Furthermore, top two risk factors (hypertension, tobacco abuse) were found to be highly associated with familial cases.

CONCLUSIONS

In this study, using a specific and well-defined large population, we reported that some key risk factors were further confirmed to be strongly associated with the pathogenesis of IA whereas further investigation into racial factors is apparently needed. Our finding of the confounding effects of top risks with familial cases further complicated the genetic analysis of IA.

How to treat hypertension in blacks: review of the evidence

Presentation, response to therapy, and clinical outcome differ according to race for patients with hypertension. Black patients have a higher prevalence and earlier onset of hypertension than other ethnic groups, with poorer prognosis than white patients. Blacks are more likely to be salt-sensitive, and to have a low plasma renin activity than are whites. They are at much greater risk of developing cardiovascular and renal complications. Despite many advances in the understanding and treatment of cardiovascular diseases, black patients continue to have increased morbidity and mortality from the end-organ complications of hypertension. The explanations for these observations remain incompletely understood, but genetic differences, added to socio-economic and environmental factors, have been proposed to explain this disparity. The first therapeutic approach is to decrease salt and increase potassium intakes. Diuretics (thiazides and potassium-sparing agents) and calcium channel blockers constitute the first antihypertensive drug choices. The angiotensin-converting-enzyme inhibitors, the angiotensin II receptor blockers and beta-blockers appear to be less effective in blacks with regard to uncomplicated hypertension, especially in older people, but addition of a small dose of diuretic improves their efficacy. These combinations are preferred among patients with chronic kidney disease or heart failure. The goal for blood pressure target is the same in blacks as it is in whites, being a blood pressure of less than 140/90 mmHg in uncomplicated hypertension and less than 130/80 mmHg in patients with diabetes mellitus or chronic kidney disease.

Influence of stroke subtype on quality of care in the Get With The Guidelines-Stroke Program

OBJECTIVE

Little is known about in-hospital care for hemorrhagic stroke. We examined quality of care in intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) admissions in the national Get With The Guidelines-Stroke (GWTG-Stroke) database, and compared them to ischemic stroke (IS) or TIA admissions.

METHODS

Between April 1, 2003, and December 30, 2007, 905 hospitals contributed 479,284 consecutive stroke and TIA admissions. The proportions receiving each quality of care measure were calculated by dividing the total number of patients receiving the intervention by the total number of patients eligible for the intervention, excluding ineligible patients or those with contraindications to treatment. Logistic regression models were used to determine associations between measure compliance and stroke subtype, controlling for patient and hospital characteristics.

RESULTS

Stroke subtypes were 61.7% IS, 23.8% TIA, 11.1% ICH, and 3.5% SAH. Performance on care measures was generally lower in ICH and SAH compared to IS/TIA, including guideline-recommended measures for deep venous thrombosis (DVT) prevention (for ICH) and smoking cessation (for SAH) (multivariable-adjusted p < 0.001 for all comparisons). Exceptions were that ICH patients were more likely than IS/TIA to have door-to-CT times <25 minutes (multivariable-adjusted p < 0.001) and to undergo dysphagia screening (multivariable-adjusted p < 0.001). Time spent in the GWTG-Stroke program was associated with improvements in many measures of care for ICH and SAH patients, including DVT prevention and smoking cessation therapy (multivariable-adjusted p < 0.001).

CONCLUSIONS

Many hospital-based acute care and prevention measures are underutilized in intracerebral hemorrhage and subarachnoid hemorrhage compared to ischemic stroke /TIA. Duration of Get With The Guidelines-Stroke participation is associated with improving quality of care for hemorrhagic stroke.

Diretrizes para o manejo de pacientes com hemorragia intraparenquimatosa cerebral espontânea

A hemorragia intraparenquimatosa cerebral (HIC) é o subtipo de AVC de pior prognóstico e com tratamento ainda controverso em diversos aspectos. O comitê executivo da Sociedade Brasileira de Doenças Cerebrovasculares, através de uma revisão ampla dos artigos publicados em revistas indexadas, elaborou sugestões e recomendações que são aqui descritas com suas respectivas classificações de níveis de evidência. Estas diretrizes foram elaboradas com o objetivo de prover o leitor de um racional para o manejo apropriado dos pacientes com HIC, baseado em evidências clínicas.

Systematic characterization of the computed tomography angiography spot sign in primary intracerebral hemorrhage identifies patients at highest risk for hematoma expansion: the spot sign score

BACKGROUND AND PURPOSE

The presence of active contrast extravasation (the spot sign) on computed tomography (CT) angiography has been recognized as a predictor of hematoma expansion in patients with intracerebral hemorrhage. We aim to systematically characterize the spot sign to identify features that are most predictive of hematoma expansion and construct a spot sign scoring system.

METHODS

We retrospectively reviewed CT angiograms performed in all patients who presented to our emergency department over a 9-year period with primary intracerebral hemorrhage and had a follow-up noncontrast head CT within 48 hours of the baseline CT angiogram. Three neuroradiologists reviewed the CT angiograms and determined the presence and characteristics of spot signs according to strict radiological criteria. Baseline and follow-up intracerebral hemorrhage volumes were determined by computer-assisted volumetric analysis.

RESULTS

We identified spot signs in 71 of 367 CT angiograms (19%), 6 of which were delayed spot signs (8%). The presence of any spot sign increased the risk of significant hematoma expansion (69%, OR=92, P<0.0001). Among the spot sign characteristics examined, the presence of > or =3 spot signs, a maximum axial dimension > or =5 mm, and maximum attenuation > or =180 Hounsfield units were independent predictors of significant hematoma expansion, and these were subsequently used to construct the spot sign score. In multivariate analysis, the spot sign score was the strongest predictor of significant hematoma expansion, independent of time from ictus to CT angiogram evaluation.

CONCLUSIONS

The spot sign score predicts significant hematoma expansion in primary intracerebral hemorrhage. If validated in other data sets, it could be used to select patients for early hemostatic therapy.

Nationwide survey of antihypertensive treatment for acute intracerebral hemorrhage in Japan

Acute hypertension is associated with hematoma enlargement and poor clinical outcomes in patients with intracerebral hemorrhage (ICH). However, the method of controlling blood pressure (BP) during the acute phase of ICH remains unknown. The aim of this study is to show current strategies about this issue in Japan. Questionnaires regarding antihypertensive treatment (AHT) strategies were sent to neurosurgeons, neurologists and others responsible for ICH management in 1424 hospitals. Of 600 respondents, 550 (92%) worked at hospitals wherein acute ICH patients are managed and 548 (99.6%) of them agreed with the application of AHT within 24 h of ICH onset. Most answered that the systolic BP threshold for starting AHT was 180 mm Hg (36%) or 160 mm Hg (31%), which differed significantly between neurosurgeons (median, 160 mm Hg) and neurologists/others (180 mm Hg, P<0.001). The goal of lowering systolic BP was to reach a maximum of 140, 150 or 160 mm Hg according to 448 respondents (82%) and 209 (38%) intensively lowered systolic BP to <or=140 mm Hg. Nicardipine was the first choice of intravenous drug for 313 (57%) and the second choice for 146 respondents (27%). However, 141 (26%) thought that nicardipine is inappropriate mainly because of a conflict with a description of contraindications on the official Japanese label for this drug. In conclusion, the present Japanese respondents, especially neurosurgeons, lower BP more aggressively than recommended in domestic and Western guidelines for managing acute ICH patients. Nicardipine was the most frequent choice of antihypertensive agent.

Cerebrovascular disease

Effective management of patients who have cerebrovascular disease depends on accurate diagnosis. Many conditions cause clinical findings that closely mimic cerebrovascular disorders and are often ruled out through brain imaging or laboratory findings. Diagnosis of cerebrovascular disorders is based on the presence of risk factors for vascular disease, the tempo of onset, the presence of concurrent conditions, and the clinical course of development of neurologic symptoms and signs. This article shares a process by which clinicians can combine a patient's history, neurologic examination, and brain and vascular imaging to localize a lesion and diagnose cerebrovascular disease.

Genome screen in familial intracranial aneurysm

BACKGROUND

Individuals with 1st degree relatives harboring an intracranial aneurysm (IA) are at an increased risk of IA, suggesting genetic variation is an important risk factor.

METHODS

Families with multiple members having ruptured or unruptured IA were recruited and all available medical records and imaging data were reviewed to classify possible IA subjects as definite, probable or possible IA or not a case. A 6 K SNP genome screen was performed in 333 families, representing the largest linkage study of IA reported to date. A 'narrow' (n = 705 definite IA cases) and 'broad' (n = 866 definite or probable IA) disease definition were used in multipoint model-free linkage analysis and parametric linkage analysis, maximizing disease parameters. Ordered subset analysis (OSA) was used to detect gene x smoking interaction.

RESULTS

Model-free linkage analyses detected modest evidence of possible linkage (all LOD < 1.5). Parametric analyses yielded an unadjusted LOD score of 2.6 on chromosome 4q (162 cM) and 3.1 on chromosome 12p (50 cM). Significant evidence for a gene x smoking interaction was detected using both disease models on chromosome 7p (60 cM; p

CONCLUSION

These data suggest it is unlikely that there is a single common variant with a strong effect in the majority of the IA families. Rather, it is likely that multiple genetic and environmental risk factors contribute to the susceptibility for intracranial aneurysms.

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Key Words Collapse

MESH Headings

• Female
• Genetic Testing
• Genotype
• Humans
• Intracranial Aneurysm/etiology
• Intracranial Aneurysm/genetics
• Linkage Disequilibrium
• Male
• Middle Aged
• Risk Factors
• Smoking/adverse effects

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Grants

• N01 HG065403 NHGRI NIH HHS
• R01 NS039512 NINDS NIH HHS
• Intramural NIH HHS
• R01 NS39512 NINDS NIH HHS

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Affiliation(s)

Tatiana Foroud Indiana University School of Medicine, Indianapolis, IN, USA
Laura Sauerbeck University of Cincinnati School of Medicine, Cincinnati, OH, USA
Robert Brown Mayo Clinic, Rochester, MN, USA
Craig Anderson The George Institute for International Health, University of Sydney, Sydney, Australia
Daniel Woo University of Cincinnati School of Medicine, Cincinnati, OH, USA
Dawn Kleindorfer University of Cincinnati School of Medicine, Cincinnati, OH, USA
Matthew L Flaherty University of Cincinnati School of Medicine, Cincinnati, OH, USA
Ranjan Deka University of Cincinnati School of Medicine, Cincinnati, OH, USA
Richard Hornung Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
Irene Meissner Mayo Clinic, Rochester, MN, USA
Joan E Bailey-Wilson National Human Genome Research Institute, Baltimore, MD, USA
Carl Langefeld Wake Forest University of Medicine, Winston-Salem, NC, USA
Guy Rouleau Center of Excellence in Neuromics, University of Montreal, Montreal, Canada
E Sander Connolly Columbia University, New York, NY, USA
Dongbing Lai Indiana University School of Medicine, Indianapolis, IN, USA
Daniel L Koller Indiana University School of Medicine, Indianapolis, IN, USA
John Huston Mayo Clinic, Rochester, MN, USA
Joseph P Broderick University of Cincinnati School of Medicine, Cincinnati, OH, USA
the FIA Study Investigators [Familial Intracranial Aneurysm Study Investigators]

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Collaborators Collapse

Effect of race/ethnicity on the efficacy of warfarin: potential implications for prevention of stroke in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia seen in clinical practice. It affects approximately 6% of persons over 65 years of age and is independently associated with a 4- to 5-fold higher risk of ischaemic stroke and a 2-fold higher risk of death. Randomized controlled trials have shown that treatment with adjusted-dose oral vitamin K antagonists (primarily warfarin with a target international normalized ratio [INR] of 2.0-3.0) reduces the relative risk of ischaemic stroke by two-thirds (an approximately 3% reduction in annual absolute risk), but is associated with a 0.2% excess annual absolute risk of intracranial haemorrhage (ICH). However, in 'real world' studies, the risk reductions in ischaemic stroke with warfarin have been significantly lower (25-50% relative risk reduction) than in selected trial samples. Moreover, more than 90% of patients enrolled in the sentinel trials were White/European. This raises the question of whether the beneficial results of warfarin can be extrapolated to persons of colour. Important differences in stroke risk profile and responsiveness to warfarin exist across racial/ethnic groups, such that one cannot assume a priori that there is a net benefit of warfarin therapy for AF patients of all racial/ethnic groups.Among patients with ischaemic stroke, AF is more likely to be implicated as the cause of stroke in the White population than in other racial/ethnic groups. Furthermore, AF may be a stronger predictor of ischaemic stroke among the White population than in Black or Hispanic/Latino populations. Approximately one-third of strokes in AF patients are noncardioembolic. Warfarin has been shown to be ineffective in preventing recurrent noncardioembolic strokes. Many persons of colour with AF have other risk factors that predispose them to noncardioembolic stroke, which may partially explain why warfarin has been reported to be less efficacious in preventing strokes in non-White patients with AF, even after adjustment for co-morbidities and anticoagulation monitoring. Notably, the background incidence of ICH is higher in Black, Hispanic and Asian patients than in White patients. Any greater than expected increases in bleeding secondary to anticoagulation may potentially offset any benefit gained from cardioembolic stroke reduction, although this has not been fully resolved.Finally, there are racial/ethnic differences in the prevalence of certain polymorphisms in genes that influence warfarin pharmacokinetics and pharmacodynamics (e.g. cytochrome P450 2C9 and vitamin K epoxide reductase). The Asian population generally appear to require the lowest daily dose of warfarin to maintain a given INR target, with the White population requiring an intermediate daily dose and the Black population requiring the highest daily dose. These differences must be taken into account when administering warfarin in order to minimize the risk of under- or over-anticoagulation.In summary, warfarin is highly effective in preventing ischaemic strokes in White patients with AF at a modestly higher risk of ICH. Whether the same net clinical benefit extends to persons of colour is unproven. Given the rapidly changing demographic nationally and internationally, additional research is needed to resolve this important question.