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

Incidence of intracerebral and subarachnoid haemorrhage in southern Sweden

OBJECTIVES

Spontaneous intracranial haemorrhage-that is, mainly subarachnoid haemorrhage (SAH) and primary intracerebral haemorrhage (PICH)-constitutes an important part of all strokes. As previous epidemiological studies have demonstrated highly variable incidence rates, we conducted a large prospective investigation of all haemorrhagic strokes during a 1 year period.

METHODS

Twelve hospitals serving a defined population of 1.14 million in southern Sweden registered all cases with spontaneous intracranial haemorrhage, including those found dead outside hospitals, during 1996. All patients were examined with CT of the brain or underwent necropsy. Incidence rates adjusted to the Swedish population for age and sex, as well as location of haematoma and prevalence of risk factors were calculated.

RESULTS

A total of 106 patients with SAH and 341 patients with PICH were identified. The annual incidence/100 000 was 10.0 (6.4 for men and 13.5 for women) for SAH and 28.4 (32.2 for men and 24.7 for women) for PICH when adjusted to the Swedish population. Subarachnoid haemorrhage affected twice as many women as men. The incidence of both types of haemorrhage increased with advancing age, but in particular, this was the case for supratentorial PICH. Lobar haematomas were the most common (51.6%) type of PICH. Among patients with PICH, 37% had hypertension, 41% other vascular disease, and 12% were on oral anticoagulation. Among patients with SAH, 28% had hypertension and 18% vascular disease before the haemorrhage but no one was on treatment with oral anticoagulation.

CONCLUSIONS

The incidence of PICH was high, especially for the older age groups. PICH was, on average, three times as common as SAH. The study underscores the importance of PICH and SAH as significant stroke subgroups.

Subarachnoid haemorrhage: epidemiology, risk factors, and treatment options

The present review focuses on subarachnoid haemorrhage (SAH) secondary to the rupture of an intracranial aneurysm, a condition with a high case fatality rate. Additionally, many of the surviving patients are left with significant disabilities. Risk factors for aneurysmal SAH include both genetic and acquired conditions. The most common presenting symptom is sudden onset of severe headache. Since headache is very common in the general population, it is not unusual that SAH is misdiagnosed at its onset with often catastrophic consequences. Unlike other acute neurological disorders such as brain injury, in which patient outcome is closely related to the extent of the injury occurring at the time of the trauma, patients with aneurysmal SAH are at risk of subsequent deterioration from 'avoidable' complications such as rebleed, vasospasm, hydrocephalus, and several other non-neurological general medical complications. Thus, the critical care management of the patient with SAH is of utmost importance in order to maximise the chances of satisfactory recovery. Although surgical clipping of the ruptured aneurysm remains the gold standard therapy, with the continuing refinement of endovascular techniques, a new, 'less invasive' option is now available, especially for patients considered poor surgical candidates.

Stroke in African Americans

There is an excess burden of cerebrovascular disease in African Americans. This article will define possible reasons for excess stroke risk, review racial differences in stroke subtype and stroke prevention programs in the African American Community, and delineate sequelae of stroke. The authors provide insights about stroke prevention in African Americans and highlight challenges to reduce the burden of cerebrovascular disease in this high-risk group.

Intracerebral hemorrhage

Intracerebral hemorrhage (ICH) represents a significant fraction of all strokes and causes a disproportionate amount of stroke related morbidity and mortality, especially in young blacks. While diagnosis of this disorder has greatly improved in the CT era, morbidity and mortality remain essentially unchanged. Not one currently utilized therapeutic modality has been clearly associated with a beneficial effect on long term outcome in small prospective randomized treatment trials for ICH. In spite of the lack of scientific data regarding therapy, patients often require aggressive medical and surgical intervention because of the life-threatening presentation of many patients. Recent clinical and experimental ICH research has identified a number of potentially effective new therapeutic strategies, and time to treatment is likely to be very important as it is for ischemic stroke. Large prospective, randomized, placebo controlled trials to examine the judicious application of current therapeutic modalities, and to investigate the potential benefit of proposed new treatment modalities, are long overdue.

Racial variation in initial stroke severity

BACKGROUND AND PURPOSE

Blacks experience greater morbidity and mortality from stroke than do whites. The degree to which this is due to the severity of the initial stroke is not known. The objective of this study is to determine whether there is a racial difference in initial stroke severity.

METHODS

A secondary analysis of a prospective cohort of 984 veterans (29.7% black) admitted to any of 9 geographically diverse Veterans Administration Hospitals for acute stroke between April 1995 and March 1997 was performed. Initial stroke severity was ascertained by using the modified Canadian Neurological Scale (CNS) applied retrospectively to medical record data. Stroke severity, unadjusted and adjusted for covariates, was compared between black and white patients.

RESULTS

Blacks had greater initial stroke severity than did whites (mean CNS score 7.96 versus 8.32, respectively; P=0.039), with a 0.5-point difference on the scale corresponding to a single-level decrement in either speech or strength of half of an extremity. This difference persisted with adjustment for other important predictors of stroke severity (P=0. 035). However, there was no significant racial difference in severity when CNS scores were collapsed into a priori clinically relevant categories.

CONCLUSIONS

Compared with whites, blacks show greater severity of stroke at hospital admission. It remains uncertain whether the relatively small but significant difference at presentation fully explains the striking racial differences in morbidity and mortality from stroke.

Incidence rates of first-ever ischemic stroke subtypes among blacks: a population-based study

BACKGROUND AND PURPOSE

The aim of this study was to determine the incidence rates of ischemic stroke subtypes among blacks.

METHODS

Hospitalized and autopsied cases of stroke and transient ischemic attack among the 187 000 blacks in the 5-county region of greater Cincinnati/northern Kentucky From January 1, 1993, through June 30, 1993, were identified. Incidence rates were age- and sex-adjusted to the 1990 US population. Subtype classification was performed after extensive review of all available imaging, laboratory data, clinical information, and past medical history. Case-control comparisons of risk factors were made with age-, race-, and sex-matched control subjects.

RESULTS

Annual incidence rates per 100 000 for first-ever ischemic stroke subtypes among blacks were as follows: uncertain cause, 103 (95% confidence interval [CI], 80 to 126); cardioembolic, 56 (95% CI, 40 to 73); small-vessel infarct, 52 (95% CI, 36 to 68); large vessel, 17 (95% CI, 8 to 26); and other causes, 17 (95% CI, 9 to 26). Of the patients diagnosed with an infarct of uncertain cause, 31% underwent echocardiography, 45% underwent carotid ultrasound, and 48% had neither. Compared with age-, race-, and sex- (proportionally) matched control subjects from the greater Cincinnati/northern Kentucky region, the attributable risk of hypertension for all causes of first-ever ischemic stroke is 27% (95% CI, 7 to 43); for diabetes, 21% (95% CI, 11 to 29); and for coronary artery disease, 9% (95% CI, 2 to 16). For small-vessel ischemic stroke, the attributable risk of hypertension is 68% (95% CI, 31 to 85; odds ratio [OR], 5.0), and the attributable risk of diabetes is 30% (95% CI, 10 to 45; OR, 4.4). For cardioembolic stroke, the attributable risk of diabetes is 25% (95% CI, 4 to 41; OR, 3.1).

CONCLUSIONS

Stroke of uncertain cause is the most common subtype of ischemic stroke among blacks. Cardioembolic stroke and small-vessel stroke are the most important, identifiable causes of first-ever ischemic stroke among blacks. The incidence rates of cardioembolic and large-vessel stroke are likely underestimated because noninvasive testing of the carotid arteries and echocardiography were not consistently obtained in stroke patients at the 18 regional hospitals. Most small-vessel strokes in blacks can be attributed to hypertension and diabetes.

Nuclear factor-kappaB and cell death after experimental intracerebral hemorrhage in rats

BACKGROUND AND PURPOSE

Nuclear factor-kappaB (NF-kappaB) is a ubiquitous transcription factor that, when activated, translocates to the nucleus, binds to DNA, and promotes transcription of many target genes. Its activation has been demonstrated in chronic inflammatory conditions, cerebral ischemia, and apoptotic cell death. The present study evaluated the presence and activation of NF-kappaB in relation to cell death surrounding intracerebral hemorrhage (ICH).

METHODS

Striatal ICH was induced in rats by the double blood injection method. Animals were killed 2, 8, and 24 hours and 4 days after ICH. To examine changes in NF-kappaB protein, Western blot was performed on brain extract. We determined NF-kappaB activity using electrophoretic mobility shift assay (EMSA) and immunohistochemistry, using an antibody that only recognizes active NF-kappaB. DNA fragmentation was detected with terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling (TUNEL) staining.

RESULTS

Western blot analysis of the NF-kappaB p65 subunit showed that there was no difference in p65 protein levels in the control, 2-hour, 8-hour, or 24-hour groups. However, ipsilateral perilesional samples from the 4-day group revealed a 1.8- to 2.5-fold increase compared with the contralateral hemisphere. Western blotting showed no differences in the inhibitor of NF-kappaB, IkappaBalpha, in any group. EMSA showed 1.3-, 2.1-, and 3.6-fold increased NF-kappaB activation in the ipsilateral striatum from the 8-hour, 24-hour, and 4-day groups, respectively, compared with the contralateral hemisphere. Immunohistochemistry, in which an activation-dependent anti-NF-kappaB antibody was used, demonstrated perivascular NF-kappaB activation as early as 2 hours after ICH with more generalized activation at 8 hours, in agreement with the EMSA results. NF-kappaB activation colocalized to cells containing fragmented DNA measured by TUNEL.

CONCLUSIONS

The present study suggests a relationship between NF-kappaB and the pathobiology of perilesional cell death after ICH.

Early surgical treatment for supratentorial intracerebral hemorrhage: a randomized feasibility study

BACKGROUND AND PURPOSE

The safety and the effectiveness of the surgical treatment of spontaneous intracerebral hemorrhage (ICH) remain controversial. To investigate the feasibility of urgent surgical evacuation of ICH, we conducted a small, randomized feasibility study of early surgical treatment versus current nonoperative management in patients with spontaneous supratentorial ICH.

METHODS

Patients with spontaneous supratentorial ICH who presented to 1 university and 2 community hospitals were randomized to surgical treatment or best medical treatment. Principal eligibility criteria were ICH volume >10 cm(3) on baseline CT scan with a focal neurological deficit, Glasgow Coma Scale score >4 at the time of enrollment, randomization and therapy within 24 hours of symptom onset, surgery within 3 hours of randomization, and no evidence for ruptured aneurysm or arteriovenous malformation. The primary end point was the 3-month Glasgow Outcome Scale (GOS). A good outcome was defined as a 3-month GOS score >3.

RESULTS

Twenty patients were randomized over 24 months, 9 to surgical intervention and 11 to medical treatment. The median time from onset of symptoms to presentation at the treating hospitals was 3 hours and 17 minutes, the time from randomization to surgery was 1 hour and 20 minutes, and the time from onset of symptoms to surgery was 8 hours and 35 minutes. The likelihood of a good outcome (primary outcome measure: GOS score >3) for the surgical treatment group (56%) did not differ significantly from the medical treatment group (36%). There was no significant difference in mortality at 3 months. Analysis of the secondary 3-month outcome measures showed a nonsignificant trend toward a better outcome in the surgical treatment group versus the medical treatment group for the median GOS, Barthel Index, and Rankin Scale and a significant difference in the National Institutes of Health Stroke Scale score (4 versus 14; P=0.04).

CONCLUSIONS

Very early surgical treatment for acute ICH is difficult to achieve but feasible at academic medical centers and community hospitals. The trend toward less 3-month morbidity with surgical intervention in patients with spontaneous supratentorial ICH warrants further investigation of very early clot removal in larger randomized clinical trials.

Racial differences in the incidence of intracerebral hemorrhage: effects of blood pressure and education

OBJECTIVE

To determine the relative risk (RR) of intracerebral hemorrhage (ICH) among African Americans compared with that among whites.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study were used to determine the incidence of ICH (n = 78) in 10,851 whites and 1,802 African Americans during a 20-year follow-up period. Cox proportional hazards analyses were used to determine the RR of ICH among African Americans compared with that among whites.

RESULTS

The estimated annual incidence of ICH was 50 per 100,000 among African Americans and 28 per 100,000 among whites. The age- and sex-adjusted RR for ICH among African Americans was 1.9 (95% confidence interval [CI], 1.1 to 3.2). With the addition of systolic blood pressure and educational attainment to the Cox proportional hazards model, the RR decreased to 1.6 (95% CI, 0.9 to 2.7). The adjustment for additional cerebrovascular disease risk factors did not change this risk estimate appreciably.

CONCLUSIONS

Compared with whites, African Americans have a twofold increased risk for ICH. Most of this risk may be explained by differences in educational attainment and systolic blood pressure. Unless additional efforts are undertaken to reduce racial differences in the prevalence of stroke risk factors, mainly systolic blood pressure and socioeconomic status, the African American-white disparities in the risk for ICH will likely continue.

Intracerebral Hemorrhage

Patients with intracerebral hemorrhage should be admitted to an intensive care unit for experienced neurologic nursing care and close attention to vital signs. We recommend gentle reduction in blood pressure in individuals who present with elevated readings and in whom hemorrhage is felt to be secondary to hypertension. For the vast majority of nontraumatic intracerebral hemorrhages, the indications for surgery and use of intracranial pressure monitoring devices remain unproven. Surgery is indicated for notable exceptions, such as for patients with cerebellar hematomas (3 mL or larger) and for patients with temporal lobe hematoma and impending brain stem compression. In general, intracranial pressure (ICP) monitoring is advised to help guide treatment with hyperosmolar agents and hyperventilation when increased ICP is suspected. For patients with smaller supratentorial hematomas who are alert or somnolent, conservative treatment is optimal. Similarly, we support conservative management in patients older than 70 years of age who present with a hemorrhage of more than 50 mL and a Glasgow Coma Scale (GCS) score of less than 8. Insufficient data exist from large randomized and controlled studies to recommend surgical intervention as definitive treatment for the group between these two extremes.

Stroke incidence and survival among middle-aged adults: 9-year follow-up of the Atherosclerosis Risk in Communities (ARIC) cohort

BACKGROUND AND PURPOSE

Although stroke mortality rates in the United States are well documented, assessment of incidence rates and case fatality are less well studied.

METHODS

A cohort of 15 792 men and women aged 45 to 64 years from a population sample of households in 4 US communities was followed from 1987 to 1995, an average of 7. 2 years. Incident strokes were identified through annual phone contacts and hospital record searching and were then validated.

RESULTS

Of the 267 incident definite or probable strokes, 83% (n=221) were categorized as ischemic strokes, 10% (n=27) were intracerebral hemorrhages, and 7% (n=19) were subarachnoid hemorrhages. The age-adjusted incidence rate (per 1000 person-years) of total strokes was highest among black men (4.44), followed by black women (3.10), white men (1.78), and white women (1.24). The black versus white age-adjusted rate ratio (RR) for ischemic stroke was 2.41 (95% CI, 1.85 to 3.15), which was attenuated to 1.38 (95% CI, 1.01 to 1.89) after adjustment for baseline hypertension, diabetes, education level, smoking status, and prevalent coronary heart disease. There was a tendency for the adjusted case fatality rates to be higher among blacks and men, although none of the case fatality comparisons across sex or race was statistically significant.

CONCLUSIONS

After accounting for established baseline risk factors, blacks still had a 38% greater risk of incident ischemic stroke compared with whites. Identification of new individual and community-level risk factors accounting for the elevated incidence of stroke requires further investigation and incorporation into intervention planning.

Cardiovascular complications in patients with primary aldosteronism

Primary aldosteronism (PA) is widely believed to be a relatively benign form of hypertension associated with a low incidence of vascular complications. However, several recent studies showed that cardiovascular complications were not rare in PA. PA is known as one of the most typical forms of sodium-sensitive hypertension. Recently, we found that the sodium sensitivity of blood pressure was a marker for greater risk for cardiovascular complications, especially stroke, in patients with essential hypertension. Therefore, we investigated cardiovascular complications in 58 patients with PA confirmed to be Conn's adenoma. Cardiovascular complications were found in 34% of 58 patients. Coronary artery disease was found in only one patient (1.7%), as angina pectoris. Stroke was found in nine patients (15.5%), four patients (6.9%) with cerebral infarctions and five patients (8.6%) with cerebral hemorrhages. Proteinuria and renal insufficiency were found in 14 (24.1%) and 4 (6.9%) patients, respectively. The incidence of cerebral infarction and renal insufficiency was greater in men than women. The prevalence of proteinuria was greater in patients with than without stroke (P = 0.03) among those aged older than 40 years. These results indicated that cardiovascular complications, especially stroke and proteinuria, were common in patients with PA, and proteinuria might be an indicator for stroke as target-organ damage.

African American antiplatelet stroke prevention study: Clinical trial design

BACKGROUND AND PURPOSE

African Americans are about two times more likely than European Americans to die of cerebrovascular disease or to experience stroke. Although this disparity exists, African Americans have been underrepresented in clinical trials. The African American Antiplatelet Stroke Prevention Study (AAASPS) is a multi-center, randomized, double-blind, clinical trial to compare the effect of ticlopidine and aspirin in the prevention of recurrent stroke, myocardial infarction, and vascular death in African Americans with recent, noncardioembolic ischemic stroke.

TRIAL DESIGN

There will be 1,800 African American noncardioembolic ischemic stroke patients at 40 sites nationally randomized to receive ticlopidine (500 mg/d) or aspirin (650 mg/d) at least 7 days but no more than 90 days after the qualifying event. Complete blood count and platelet count are monitored every 2 weeks during the first 3 months of active treatment to monitor for neutropenia and thrombocytopenia. Patients with transient cerebral ischemia, recent active peptic ulcer disease or lower gastrointestinal bleeding, bleeding diathesis, and women of childbearing potential are excluded. Study patients will be followed-up for a total of 2 years for occurrence of the primary outcome endpoint cluster of recurrent stroke, myocardial infarction, and vascular death. Safety analyses will focus on the incidence of severe adverse events such as neutropenia, thrombocytopenia, gastrointestinal bleeding, and liver dysfunction. Analyses for key endpoints will use the intention-to-treat principle and time-to-event data will be analyzed using Mantel-Haenszel and various regression methods.

CONCLUSION

African Americans have a survival disadvantage that substantially relates to the occurrence of stroke. AAASPS is the first secondary stroke prevention study exclusively for African Americans and promises to provide important information to guide recurrent stroke prevention treatment for this high-risk group.

Plasma fibrinogen of black South Africans: the BRISK study

OBJECTIVE

To describe the distribution of plasma fibrinogen and relationships with other risk factors for coronary heart disease (CHD) and stroke in the black population of the Cape Peninsula.

DESIGN

A cross-sectional survey of a stratified proportional sample of randomly selected black men and women.

SETTING

Households in Gugulethu, Langa, Nyanga, New Crossroads, KTC, Old Crossroads and Khayelitsha in the Cape Peninsula, South Africa.

SUBJECTS

One subject per household (352 men and 447 women), aged 15-64 years, voluntarily participated. Visitors, pregnant, lactating, ill, mentally retarded and intoxicated subjects were excluded.

RESULTS

Mean fibrinogen (thrombin time coagulation method) of men and women were higher than published data for Europeans but slightly lower than values of black Americans. Women aged 45-54 years had the highest level (3.13+/-0.89 g l(-1)) and men aged 15-24 years had the lowest (2.13+/-0.88 g l(-1)). Fifteen per cent of the men and 12% of the women had a level greater than 1 standard deviation of the mean for their age group. Univariate and multivariate analyses revealed significant (P<0.05) positive correlations of fibrinogen with smoking habit, age, body mass index (BMI), total and low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure and white blood cell count, and significant negative correlations with high-density lipoprotein (HDL) cholesterol, gamma glutamyl transferase (GGT), serum iron and ferritin. The correlations with BMI, serum lipoproteins, iron, ferritin, and GGT suggest that nutritional status and therefore diet influences plasma fibrinogen.

CONCLUSION

Relatively high fibrinogen levels, tending to cluster with other, including diet-related, risk factors for CHD and stroke, were observed in black South Africans. It is suggested that fibrinogen may contribute to the high stroke incidence of this population group.

Risk factors for multiple intracranial aneurysms

OBJECTIVE

Risk factors that predispose to the formation of multiple intracranial aneurysms, which are present in up to 34% of patients with intracranial aneurysms, are not well defined. In this study, we examined the association between known risk factors for cerebrovascular disease and presence of multiple intracranial aneurysms.

METHODS

We reviewed the medical records and results of conventional angiography in all patients with a diagnosis of intracranial aneurysms admitted to the Johns Hopkins University hospital between January 1990 and June 1997. We determined the independent association between various cerebrovascular risk factors and the presence of multiple aneurysms using logistic regression analysis.

RESULTS

Of 419 patients admitted with intracranial aneurysms (298 ruptured and 121 unruptured), 127 (30%) had multiple intracranial aneurysms. In univariate analysis, female gender (odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.1-3.3) and cigarette smoking at any time (OR = 1.8; 95% CI, 1.1-3.0) were significantly associated with presence of multiple aneurysms. In the multivariate analysis, cigarette smoking at any time (OR = 1.7; 95% CI, 1.1-2.8) and female gender (OR = 2.1; 95% CI 1.2-3.5) remained significantly associated with multiple aneurysms. Hypertension, diabetes mellitus, and alcohol and illicit drug use were not significantly associated with presence of multiple aneurysms.

CONCLUSION

Cigarette smoking and female gender seem to increase the risk for multiple aneurysms in patients predisposed to intracranial aneurysm formation. Further studies are required to investigate the mechanism underlying the association between cigarette smoking and intracranial aneurysm formation.

The Greater Cincinnati/Northern Kentucky Stroke Study: preliminary first-ever and total incidence rates of stroke among blacks

BACKGROUND AND PURPOSE

The Greater Cincinnati/Northern Kentucky Stroke Study was designed to be the first large, population-based metropolitan study of temporal trends in stroke incidence rates and outcome within a biracial population.

METHODS

We are identifying all hospitalized and autopsied cases of stroke and transient ischemic attack (TIA) among the 1.3 million inhabitants of a five-county region of Greater Cincinnati/Northern Kentucky for the period 7/1/93-6/30/94. We have already prospectively monitored for out-of-hospital stroke and TIAs for this same time period at 128 screening sites, including a random sample of all primary care physicians and nursing homes in the region. We have already identified all hospitalized and autopsied cases of stroke and TIA among blacks for 1/1/93-6/30/93 and report preliminary incidence rates for this 6-month period.

RESULTS

The overall incidence rate for all first-ever hospitalized or autopsied stroke (excluding TIAs) among blacks in the Greater Cincinnati region was 288 per 100000 (95% CI, 250 to 325, age- and sex-adjusted to 1990 US population). The overall incidence rate for first-ever and recurrent stroke (excluding TIAs) was 411 per 100000 (95% CI, 366 to 456). By comparison, the overall incidence rate of first-ever stroke among whites in Rochester, Minn, during the period 1985-1989 was 179 per 100000 (95% CI, 164 to 194, age- and-sex adjusted to 1990 US population). The incidence rates among blacks in Greater Cincinnati were substantially greater than the rates among whites in Rochester, Minn, for all age categories except ages 75 and older, for which the rates were similar.

CONCLUSIONS

We conservatively estimate that 731100 first-ever or recurrent strokes occurred in the United States during 1996. Studies of first-ever as well as total stroke among biracial and representative populations are critical for understanding temporal trends in the incidence rate and the burden of stroke in the US population.

Hypertension in special populations

Essential hypertension is a common disorder, and a variety of antihypertensive drugs are available to lower blood pressure in the normal range. Identifying special subpopulations by differences in age, gender, race, and body weight has taught clinicians to be more selective in antihypertensive therapy. The rationale for this selectivity is often speculative and has not been corroborated by any hard data. It is hoped that some of the prospective, randomized trials currently in progress will throw some light on this question.

Elastin degradation in the superficial temporal arteries of patients with intracranial aneurysms reflects changes in plasma elastase

OBJECTIVE

alpha 1-Antitrypsin (AAT) and alpha 2-macroglobulin (AMG) are elastase inhibitors that bind the enzyme and reduce measured levels of free elastase. It was recently demonstrated that some patients with intracranial aneurysms have significantly elevated plasma elastase (PE) levels. Although this elevation is unrelated to plasma AAT, it is unknown whether abnormal AAT phenotypes or reduced AMG levels play a role. Moreover, the pathological significance of this elevation is not understood.

METHODS

Plasma from 24 patients with aneurysms (ruptured, n = 15; unruptured, n = 9) and 10 age-matched patients who comprised a control group was analyzed for PE and AMG levels by enzyme-linked immunosorbent assay and for AAT phenotype by isoelectric focusing. Sections of superficial temporal temporal artery obtained from these patients at the time of surgery were examined for evidence of elastin degradation by using a van Gieson stain, with scoring on a nine-point quantitative scale.

RESULTS

Patients with aneurysms showed significantly elevated PE levels (119 +/- 28 versus 17 +/- 7 micrograms/ml, P < 0.05), but AMG levels were not decreased. AAT phenotypic abnormalities were observed in 10% (2 of 20) of the patients with aneurysms, but this was not different from the expected population incidence (7%). Elastin degradation scores were significantly higher in patients with aneurysms than in patients control group (4.26 +/- 0.54 versus 1.21 +/- 0.43, P < 0.05). In addition, patients with higher elastase levels (> 80 micrograms/ml) demonstrated 55% higher degradation scores than did those with lower elastase levels (< 80 micrograms/ml).

CONCLUSION

These data suggest that high PE levels may play a role in systemic arterial elastin degradation seen in patients with intracranial aneurysms. These data also support the contention that elevated elastase levels are not the result of decreased protease inhibitor levels. Although PE levels were significantly higher for the entire group of patients with aneurysms, this assay has relatively low sensitivity for predicting the presence of unruptured aneurysms. Additional study is necessary to determine whether serum elastase levels greater than 80 micrograms/ml, in the setting of other risk factors, are useful in identifying asymptomatic patients for additional screening.

Association of the angiotensinogen gene to serum angiotensinogen in blacks and whites

A variant of the angiotensinogen gene (AGT) that encodes for threonine at codon 235 (T235) has been associated with a higher serum angiotensinogen concentration and with hypertension in white subjects. The frequency of T235 is about two times higher in blacks than whites, suggesting that AGT may contribute to the susceptibility to hypertension in blacks more than it does in whites. However, an association of T235 with angiotensinogen level or blood pressure has not been observed in blacks, possibly because the high prevalence of T235 makes it insufficiently informative as a marker. For this reason, we undertook to further differentiate the T235 carrier state by constructing haplotypes with alleles in the 5' upstream region of AGT. One such haplotype, -1074t;T235, showed a significant association with angiotensinogen level in a cohort of black and white children and adolescents (76 blacks, mean age = 12.3 +/- 2.0 [SD] years; 139 whites, mean age = 12.4 +/- 1.8 years). With a linear regression model, the level of serum angiotensinogen was significantly related to body mass index (P = .0017) and the haplotype (P = .0001). Within specific race groups, the haplotype was significantly related to serum angiotensinogen in both the blacks (P = .0277) and whites (P = .0001). The mean level of angiotensinogen was higher in the blacks carrying a single copy of the haplotype than in those without the haplotype (1472.2 +/- 68.4 versus 1274.9 +/- 46.7 nmol angiotensin I/L), a difference that was marginally significant (P = .0609). In the whites, the level of angiotensinogen was also higher in carriers of a single copy than in those with no copy (1527.9 +/- 71.2 versus 1099.2 +/- 20.1 nmol angiotensin I/L) (P = .0003). Serum angiotensinogen level did not increase with two copies of the haplotype, but in each racial group, there were only four individuals who were homozygous. The haplotype showed a marginally significant relation (P = .0757) to the mean of longitudinally determined diastolic pressures adjusted for body mass index, race, sex, and age. In summary, using a haplotype to differentiate further the T235 carrier state, we observed an association of genotype with serum angiotensinogen level and blood pressure in blacks and whites. The findings suggest that AGT may play an important role in blood pressure regulation in both racial groups.

Intracerebral hemorrhage in blacks. Risk factors, subtypes, and outcome

BACKGROUND AND PURPOSE

Blacks are at a higher risk for intracerebral hemorrhage (ICH) than whites; however, few data are available regarding the demographic and clinical characteristics of ICH among blacks.

METHODS

We determined the frequency of risk factors, etiologic subtypes, and outcome among consecutive black patients admitted with nontraumatic ICH to a university-affiliated public hospital.

RESULTS

The most common risk factors in the 403 black patients with ICH were preexisting hypertension (77%), alcohol use (40%), and smoking (30%). Among the 91 nonhypertensive patients, 21 (23%) were diagnosed with hypertension after onset. Compared with women, men had a younger age of onset (54 versus 60 years; P < .001) and higher frequency of alcohol use (54% versus 22%; P < .001) and smoking (39% versus 17%; P < .001). ICH secondary to hypertension (n = 311) and of undetermined etiology (n = 73) were the most common subtypes in blacks. Patients aged 65 years and older (compared with those aged 15 to 44 years; P = .001) and women (compared with men; P = .02) were more likely to be dependent at discharge.

CONCLUSIONS

Primary preventive strategies are required to reduce the high frequency of modifiable risk factors predisposing to ICH in blacks.

Early hemorrhage growth in patients with intracerebral hemorrhage

BACKGROUND AND PURPOSE

The goal of the present study was to prospectively determine how frequently early growth of intracerebral hemorrhage occurs and whether this early growth is related to early neurological deterioration.

METHODS

We performed a prospective observational study of patients with intracerebral hemorrhage within 3 hours of onset. Patients had a neurological evaluation and CT scan performed at baseline, 1 hour after baseline, and 20 hours after baseline.

RESULTS

Substantial growth in the volume of parenchymal hemorrhage occurred in 26% of the 103 study patients between the baseline and 1-hour CT scans. An additional 12% of patients had substantial growth between the 1- and 20-hour CT scans. Hemorrhage growth between the baseline and 1-hour CT scans was significantly associated with clinical deterioration, as measured by the change between the baseline and 1-hour Glasgow Coma Scale and National Institutes of Health Stroke Scale scores. No baseline clinical or CT prediction of hemorrhage growth was identified.

CONCLUSIONS

Substantial early hemorrhage growth in patients with intracerebral hemorrhage is common and is associated with neurological deterioration. Randomized treatment trials are needed to determine whether this early natural history of ongoing bleeding and frequent neurological deterioration can be improved.

Relationship of cardiovascular risk factors to racial differences in femoral bypass surgery and abdominal aortic aneurysmectomy in Massachusetts

Atherosclerosis is more severe in blacks than in whites, but abdominal aortic aneurysms, which have traditionally been thought to have an atherosclerotic etiology, appear to be less common in blacks. Because of this incongruity, we compared risk factor profiles in patients undergoing abdominal aortic aneurysm repair and patients undergoing femoral bypass for atherosclerotic occlusive disease. A dual case-control study was conducted, first, comparing patients who had undergone aneurysmectomy to a control group of patients who had undergone appendectomy; and then comparing patients who had undergone femoral bypass surgery to the same appendectomy controls. We initially used hospital discharge data for the entire state of Massachusetts and, in a second phase, data obtained from a review of medical records from Boston University Medical Center Hospital and Boston City Hospital. The statewide database indicated that rates of femoral bypass surgery were higher in blacks than in whites, but after adjusting for differences in hypertension, diabetes, and low socioeconomic status, the black/white odds ratio for femoral bypass fell to 1.44 (95% confidence interval: 1.08, 1.92). A similar analysis based on the hospital chart review, provided better control of confounding and indicated that there was no racial difference in rates of femoral bypass after correcting for other risk factors (odds ratio = 0.94; 95% confidence interval: 0.40, 2.22; p = 0.90). In contrast, the statewide database found higher rates of abdominal aortic aneurysm surgery in whites, and particularly in white males. Smoking and hypertension were strong risk factors for aneurysmectomy, but diabetes mellitus and socioeconomic status were not. After adjusting for other variables, the black/white odds ratio for aneurysmectomy was 0.29 (95% confidence interval: 0.07, 1.23; p = 0.09).

CONCLUSIONS

Substantial differences are found in the risk factor profiles for aneurysmal disease and femoral atherosclerotic occlusive disease. Diabetes is a particularly strong risk factor for femoral disease, but not for aneurysmal disease. In addition, blacks had higher rates of femoral bypass surgery in Massachusetts, but the apparent racial difference appeared to be due to a greater prevalence of hypertension, smoking, and diabetes in blacks. In contrast, abdominal aortic aneurysms occurred predominantly in white males, and adjustment for other risk factors further accentuated the greater risk in whites.

Lifetime cost of stroke in the United States

BACKGROUND AND PURPOSE

Stroke imposes a substantial economic burden on individuals and society. This study estimates the lifetime direct and indirect costs associated with the three major types of stroke: subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH), and ischemic stroke (ISC).

METHODS

We developed a model of the lifetime cost of incident strokes occurring in 1990. An epidemiological model of stroke incidence, survival, and recurrence was developed based on a review of the literature. Data on direct cost of treating stroke were obtained from Medicare claims data, the 1987 National Medical Expenditure Survey (NMES), and insurance claims data representing a group of large, self-insured employers. Indirect costs (the value of foregone market and nonmarket production) associated with premature morbidity and mortality were estimated based on data from the US Bureau of Economic Analysis and the 1987 NMES.

RESULTS

The lifetime cost per person of first strokes occurring in 1990 is estimated to be $228,030 for SAH, $123,565 for ICH, $90,981 for ISC, and $103,576 averaged across all stroke sub-types. Indirect costs accounted for 58.0% of lifetime costs. Aggregate lifetime cost associated with an estimated 392,344 first strokes in 1990 was $40.6 billion: $5.6 billion for SAH, $6.0 billion for ICH, and $29.0 billion for ISC. Acute-care costs incurred in the 2 years following a first stroke accounted for 45.0%, long-term ambulatory care accounted for 35.0%, and nursing home costs accounted for 17.5% of aggregate lifetime costs of stroke.

CONCLUSIONS

The lifetime cost of stroke varies considerably by type of stroke and entails considerable costs beyond the first 2 years after a stroke.

The ABCs of measuring intracerebral hemorrhage volumes

BACKGROUND AND PURPOSE

Hemorrhage volume is a powerful predictor of 30-day mortality after spontaneous intracerebral hemorrhage (ICH). We compared a bedside method of measuring CT ICH volume with measurements made by computer-assisted planimetric image analysis.

METHODS

The formula ABC/2 was used, where A is the greatest hemorrhage diameter by CT, B is the diameter 90 degrees to A, and C is the approximate number of CT slices with hemorrhage multiplied by the slice thickness.

RESULTS

The ICH volumes for 118 patients were evaluated in a mean of 38 seconds and correlated with planimetric measurements (R2 = 9.6). Interrater and intrarater reliability were excellent, with an intraclass correlation of .99 for both.

CONCLUSIONS

We conclude that ICH volume can be accurately estimated in less than 1 minute with the simple formula ABC/2.

Clinical epidemiology of stroke

The effect of stroke as a major health issue in the United States is well established. Well-designed epidemiologic studies have contributed important information about the natural history of stroke and its associated risk factors. These cerebrovascular profiles have provided the foundation for many of the current ischemic stroke trials, but the cause and prevention of the hemorrhagic subtypes remain elusive.

Stroke in young black patients. Risk factors, subtypes, and prognosis

BACKGROUND AND PURPOSE

Stroke subtypes and prognosis differ among older black patients compared with whites; however, few data are available regarding stroke among young black patients.

METHODS

To determine the risk factors for stroke, stroke subtype, and prognosis among young black patients, we retrospectively reviewed the medical records of all 15- to 44-year-old patients admitted with stroke to a university-affiliated public hospital from January 1990 through June 1994.

RESULTS

Of the 248 eligible patients admitted with stroke, 219 were blacks. Hypertension was more frequently associated with stroke in young black than in non-black patients (55% versus 24%, P = .003). Cocaine abuse was frequent among both black and non-black patients (27% versus 38%, P = NS). Hypertensive intracerebral hemorrhage (64%) was the most common subtype of intracerebral hemorrhage (n = 67), and lacunar infarction (21%) was the most common subtype of cerebral infarction (n = 112) in young black patients. Outcome in black patients with stroke at discharge was 69% independent, 8% dependent, and 23% dead.

CONCLUSIONS

The high frequency of hypertension, hypertensive intracerebral hemorrhage, and lacunar infarction among young black patients with stroke suggests accelerated hypertensive arteriolar damage, possibly due to poor control of hypertension.

Predictors of early deterioration and mortality in black Americans with spontaneous intracerebral hemorrhage

BACKGROUND AND PURPOSE

Black Americans with spontaneous intracerebral hemorrhage (SICH) may have unique clinical characteristics that affect outcome. The aim of this study was to determine the prognostic value of clinical characteristics and initial CT scan for outcome in black Americans with SICH.

METHODS

Clinical and demographic data were extracted from the charts of 182 consecutive black Americans admitted for SICH diagnosed by clinical criteria and initial CT scan. Hemorrhage volumes were calculated from admission CT scans by a computerized method. Univariate and multiple logistic regression analyses were performed to determine independent predictors of early deterioration (defined as a decrease from an initial Glasgow Coma Scale score > 12 by > or = 4 points within 24 hours from presentation) and mortality.

RESULTS

Both hemorrhage volume and ventricular extension were significant, independent predictors of early deterioration (odds ratio [OR], 6.78; 95% confidence interval [CI], 1.89 to 24.35 and OR, 4.67; 95% CI, 1.30 to 16.72, respectively) and mortality (OR, 6.66; 95% CI, 2.85 to 15.58 and OR, 4.23; 95% CI, 1.82 to 9.82, respectively). A Glasgow Coma Scale score < or = 12 also predicted mortality (OR, 3.23; 95% CI, 1.46 to 7.14). Initial mean arterial pressure was not an independent predictor of early deterioration or mortality.

CONCLUSIONS

Hemorrhage volume and ventricular extension are the best predictors of early deterioration and mortality in black Americans with SICH.

Familial aneurysmal subarachnoid hemorrhage: a community-based study

The familial occurrence of intracranial aneurysms has been well described. However, intracranial aneurysms are not rare and the great majority of reported families consist of only two affected members. Therefore, the familial aggregation of intracranial aneurysms could be fortuitous. The authors investigated the familial occurrence of aneurysmal subarachnoid hemorrhage (SAH) in their community to determine whether family members of patients with a ruptured aneurysm are at an increased risk of developing an SAH. All 81 patients from Rochester, Minnesota, who suffered an SAH between 1970 and 1989 from a proven aneurysmal rupture were identified, and they or their families were contacted and a family history was obtained. The number of expected SAHs among first-degree relatives was calculated using previously established age- and sex-specific incidence rates in the community of Rochester. Of the 81 index patients, 76 had complete follow up for family history. Fifteen (20%) of these 76 patients had a first- or second-degree relative with aneurysmal SAH. The number of observed first-degree relatives with aneurysmal SAH was 11, compared to an expected number of 2.66, giving a relative risk of 4.14 (95% confidence interval 2.06-7.40; p < 0.001). In the authors' community, aneurysmal SAH was familial in one of five patients, and this familial aggregation was not fortuitous. The increase in familial risk of aneurysmal SAH is approximately fourfold among first-degree relatives.

Quantification of operative benefit for unruptured cerebral aneurysms: a theoretical approach

The indications for surgery on unruptured asymptomatic cerebral aneurysms are still unclear. In this report, the authors use mathematical methods to attempt to quantify the benefit of surgery for unruptured aneurysms. Theoretical survival curves for either operative or conservative treatment were obtained by solving differential equations on the survival rate of a patient harboring an unruptured aneurysm. Patients' life expectancies were calculated as areas under these curves, and operative benefit was quantified as a gain in average life expectancy. To analyze morbidity, two concepts were introduced: premorbid survival rate and average premorbid survival period, and the operative gain of average premorbid survival period was calculated under certain assumptions. Larger operative benefit was observed in younger patients, with increasingly less benefit in the elderly. The operative gain of average life expectancy was 3.9 years for a 40-year-old patient, 2.4 years for 50, 1.3 years for 60, and 0.6 years for a 70-year-old. Quantified operative benefit is presented in a table for various patient ages, yearly rupture rates, and expected operative morbidity and mortality. This mathematical method would be useful to both surgeons and patients in making their decisions on surgery.

Linkage of the angiotensinogen gene locus to human essential hypertension in African Caribbeans

The renin-angiotensin system regulates blood pressure and sodium balance. The angiotensinogen gene which encodes the key substrate within this system has been linked to essential hypertension in White Europeans. It has been suggested that people of West African ancestry may have a different genetic basis for hypertension. In this study we have tested whether there is linkage of the angiotensinogen gene to essential hypertension in African Caribbeans from St. Vincent and the Grenadines. DNA from 63 affected sibling pairs with hypertension was tested for linkage by analyzing whether there was excess allele sharing among siblings genotyped using an angiotensinogen dinucleotide repeat sequence. There was significant support for linkage (T = 3.07, P = 0.001) and association of this locus to hypertension (chi 2 = 50.2, 12 degrees of freedom, P << 0.001). A DNA polymorphism which alters methionine to threonine at position 235 (M235T) within the angiotensinogen peptide has been associated previously with hypertension. However, we found no association of this variant with hypertension in this study. These findings provide support for linkage and association of the angiotensinogen locus to hypertension in African Caribbeans and suggest some similarities in the genetic basis of essential hypertension in populations of different ethnicity.

Validation and comparison of models predicting survival following intracerebral hemorrhage

OBJECTIVE

To compare the performance of two previously reported logistic regression models using data independent from those data used to derive the models.

DESIGN

Prospective.

SETTING

Acute stroke unit of a tertiary care hospital.

PATIENTS

One hundred twenty-nine patients with supratentorial intracerebral hemorrhage.

MEASUREMENTS AND MAIN RESULTS

Model 1 contains the initial Glasgow Coma Scale score, hemorrhage size, and pulse pressure. The more complex model 2 includes, in addition to those three variables, the presence or absence of intraventricular hemorrhage and a term representing the interaction of intraventricular hemorrhage and Glasgow Coma Scale score. The areas under the receiver operating characteristic curves generated for each model were statistically indistinguishable.

CONCLUSIONS

Model 1 predicts 30-day patient status as well as the more complex model 2. Model 1 provides a valid, easy-to-use means of categorizing supratentorial intracerebral hemorrhage patients in terms of their probability of survival.

The poor prognosis of ruptured intracranial aneurysms of the posterior circulation

The first 48 hours after aneurysmal subarachnoid hemorrhage are critical in determining final outcome. However, most patients who die during this initial period are not included in hospital-based studies. We investigated the occurrence of subarachnoid hemorrhage in a population-based study to evaluate possible predictors of poor outcome. All patients diagnosed with aneurysmal subarachnoid hemorrhage between 1955 and 1984 were selected for analysis of mortality in the first 30 days using the medical record-linkage system employed for epidemiological studies in Rochester, Minnesota. One hundred and thirty-six patients were identified. The mean age of these 99 women and 37 men was 55 years. Rates for survival to 48 hours were 32% for the 19 patients with posterior circulation aneurysms, 77% for the 87 patients with anterior circulation aneurysms, and 70% for the 30 patients with a presumed aneurysm (p < 0.0001). Rates for survival to 30 days were 11%, 57%, and 53%, respectively, in these three patient groups (p < 0.0001). Clinical grade on admission to the hospital, the main variable predictive of death within 48 hours, was significantly worse in patients with posterior circulation aneurysms than in others (p < 0.0001). The prognosis of ruptured posterior circulation aneurysms is poor. The high early mortality explains why posterior circulation aneurysms are uncommon in most clinical series of patients with subarachnoid hemorrhage. The management of incidentally discovered intact posterior circulation aneurysms may be influenced by these findings.

3-D image analysis of intra-cerebral brain hemorrhage from digitized CT films

A new 3-D technique for the segmentation and quantification of human spontaneous intra-cerebral brain hemorrhage (ICH) is presented in this paper. The algorithm for ICH primary region segmentation uses the spatially weighted K-means histogram-based clustering algorithm. The ICH edema region segmentation algorithm employs an iterative morphological processing of the ICH brain data. A volume rendering technique is used for the effective 3-D visualization of ICH segmented regions. A computer program is developed for use in the human spontaneous ICH study involving a large number of patients. Experimental measurements and visualization results are presented which were computed on real ICH patient brain data.

Racial differences in the incidence of femoral bypass and abdominal aortic aneurysmectomy in Massachusetts: relationship to cardiovascular risk factors

PURPOSE

Atherosclerotic disease appears to be more severe in black patients than in white patients, but abdominal aortic aneurysms, which have traditionally been believed to have an atherosclerotic cause, are reported to be less common in black patients than in white patients. Our goals were to compare and contrast factors associated with the development of abdominal aortic aneurysms and clinically significant atherosclerotic occlusive disease (1) to determine whether these diseases share a common cause and (2) to explore their association with race.

METHODS

Dual case-control studies were conducted with multivariate analysis to compare cases (patients undergoing aneurysmectomy or patients undergoing femoral bypass) with a comparison group consisting of patients who had undergone appendectomy. Two data sources were used: (1) hospital discharge data for Massachusetts from 1984 through 1988 and (2) medical records at University Hospital of Boston and Boston City Hospital. For both the Massachusetts database and the hospital chart review, records were obtained for all patients discharged between January 1984 and December 1988 with an International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code for abdominal aortic aneurysm resection (38.44) or aneurysmorrhaphy (38.34) or with a procedure code for femoral artery bypass/reconstruction (39.29). To conduct a nested case-control study, records were also obtained for a control group consisting of patients between the ages of 50 and 84 years who had undergone appendectomy during the same 5-year period.

RESULTS

Black patients had higher rates of femoral bypass than did white patients after adjustment for age and sex (odds ratio = 1.97; 95% confidence interval: 1.49, 2.61; p < 0.0001). However, femoral bypass was also associated with hypertension, diabetes, and low household income. After adjusting for these additional factors in the statewide data set, the black/white odds ratio for femoral bypass was only 1.44 (95% confidence interval: 1.08, 1.92). The parallel case-control study at University Hospital and Boston City Hospital, which provided information about smoking status and more accurate ascertainment of coexisting hypertension and diabetes, indicated that there was no racial difference in rates of femoral bypass after correcting for these additional risk factors (odds ratio = 0.94; 95% confidence interval: 0.40, 2.22; p = 0.90). In contrast, abdominal aortic aneurysmectomy occurred predominantly in white men. Aneurysmectomy was also associated with smoking and hypertension, but aneurysmectomy was not significantly associated with diabetes mellitus or family income. The black/white odds ratio for aneurysm was 0.29; (95% confidence interval: 0.07, 1.23; p = 0.09 after adjustment for other variables).

CONCLUSIONS

Hypertension, smoking, and male sex are risk factors for the development of femoral atherosclerosis and abdominal aortic aneurysm formation. However, abdominal aortic aneurysms occur predominantly in white men and do not appear to be associated with diabetes mellitus or income. In contrast, the higher rate of femoral artery bypass in black patients is probably the result of greater prevalence among black patients of hypertension, diabetes, smoking, and perhaps by other ill-defined factors associated with socioeconomic status.

Race-ethnicity and determinants of intracranial atherosclerotic cerebral infarction. The Northern Manhattan Stroke Study

BACKGROUND AND PURPOSE

The aim of this investigation was to determine the importance of race as a determinant of intracranial atherosclerotic stroke in a community-based stroke sample.

METHODS

Residents from northern Manhattan over age 39 years hospitalized for acute ischemic stroke (n = 438, black 35%, Hispanic 46%, white 19%) were prospectively evaluated. Index ischemic strokes were classified as atherosclerotic (17%), lacunar (30%), cardioembolic (21%), cryptogenic (31%), and other (1%). Atherosclerotic infarcts were subdivided into extracranial (9%) and intracranial (8%) atherosclerosis.

RESULTS

The proportion of extracranial atherosclerotic stroke was similar among the three race-ethnic groups, while intracranial atherosclerosis was more frequent in blacks and Hispanics. The unadjusted odds ratio for nonwhites (blacks and Hispanics combined) was 0.8 (confidence interval [CI], 0.4 to 1.8) for extracranial and 7.8 (CI, 1.04 to 57.7) for intracranial atherosclerosis. Patients with intracranial disease were significantly younger and had an increased frequency of hypercholesterolemia and insulin-dependent diabetes compared with those with nonatherosclerotic disease. The odds ratio for the association of nonwhite race-ethnicity and intracranial atherosclerosis was reduced to 5.2 (CI, 0.7 to 40) after controlling for age and to 4.4 (CI, 0.6 to 35) after controlling for age, education, insulin-dependent diabetes, and hypercholesterolemia.

CONCLUSIONS

The greater prevalence of diabetes and hypercholesterolemia among blacks and Hispanics from northern Manhattan accounted for much of the increased frequency of intracranial atherosclerotic stroke. Further control of these risk factors could reduce the frequency of this stroke subtype and minimize the disparities among different race-ethnic groups.

Subarachnoid hemorrhage: an update of pathogenesis, diagnosis and management

Subarachnoid hemorrhage (SAH) remains a devastating neurological disorder, which most commonly develops after rupture of an intracranial aneurysm. Advances have occurred in the areas of epidemiology, diagnostic imaging, medical management and surgical intervention, related to aneurysmal SAH. Interested physicians must become aware of these and other advances to diagnose and manage this potentially lethal disorder more effectively. This review provides information about the pathogenesis and complications of aneurysmal SAH and an update of new and evolving treatment modalities to provide an in-depth overview for the clinician and researcher involved in this rapidly evolving field.