Migraine-Associated Common Genetic Variants Confer Greater Risk of Posterior vs. Anterior Circulation Ischemic Stroke☆.

OBJECTIVE: To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects. METHODS: Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype. RESULTS: Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses. CONCLUSIONS: Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.

Detailed phenotyping of posterior vs. anterior circulation ischemic stroke: a multi-center MRI study.

OBJECTIVE: Posterior circulation ischemic stroke (PCiS) constitutes 20-30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS. METHODS: Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression. RESULTS: PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p < 0.05; male sex 68% vs. 58%, p < 0.001). Both were independently associated with PCiS (diabetes, OR = 1.29; 95% CI 1.04-1.61; male sex, OR = 1.46; 95% CI 1.21-1.78). ACiS more commonly had large artery atherosclerosis (25% vs. 20%, p < 0.01) and cardioembolic mechanisms (17% vs. 11%, p < 0.001) compared to PCiS. Small artery occlusion was more common in PCiS vs. ACiS (20% vs. 14%, p < 0.001). Small artery occlusion accounted for 47% of solitary brainstem infarctions. CONCLUSION: Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.

Natural history of complications after intracerebral haemorrhage.

BACKGROUND AND PURPOSE: Numerous trials of haemostatic and neuroprotective agents for intracerebral haemorrhage (ICH) have failed. We characterized the risk of complications after ICH in a trial-eligible patient population, to inform safety in future trials. METHODS: We used the Virtual International Stroke Trials Archive database to identify placebo-treated patients with spontaneous ICH, who were not comatose at admission, where randomization took place within 4 h of symptom onset, and where serious complication and outcome data were available. We described the complications encountered and assessed whether the absence of common complications influenced attainment of good functional outcome (mRS < or =4) at 90 days using logistic regression. RESULTS: Of 201 patients examined, 70.2% experienced at least one serious complication. Neurological complications occurred in 21%, infections amongst 11%, and thromboembolic complications in 2%. Extension of the haemorrhage occurred most frequently: its absence was a significant predictor of good functional outcome (P < 0.0001, adjusted OR for good functional outcome = 21.9, 95% CI: [5.5, 88.3]). Neither infection, nor cardiac, nor thromboembolic complications influenced functional outcome at 90 days. CONCLUSIONS: Three month outcome in ICH patients depends on initial stroke severity and on enlargement of the haemorrhage. Our results should inform safety in future clinical trials of putative ICH therapies.

Oral anticoagulation in patients with cardiomyopathy or heart failure in sinus rhythm.

BACKGROUND: Despite many prospective randomized studies defining the benefits of anticoagulation in atrial fibrillation (AF), there have been no adequate studies in cardiomyopathy (CM) in sinus rhythm. METHODS: We review the current knowledge of the risk of stroke in CM, left ventricular systolic dysfunction and heart failure as well as the indications for antithrombotic agents and compare this with AF. RESULTS: The current knowledge of risk factors for stroke and indications for antithrombotic agents in CM is similar to that of AF prior to the treatment studies of the 1980s-1990s. CONCLUSION: Prospective randomized trial data are urgently needed to determine the role of antithrombotic drugs in CM.

Brain Perivascular Spaces as Biomarkers of Vascular Risk: Results from the Northern Manhattan Study.

BACKGROUND AND PURPOSE: Dilated perivascular spaces in the brain are associated with greater arterial pulsatility. We hypothesized that perivascular spaces identify individuals at higher risk for systemic and cerebral vascular events. MATERIALS AND METHODS: Stroke-free participants in the population-based Northern Manhattan Study had brain MR imaging performed and were followed for myocardial infarction, any stroke, and death. Imaging analyses distinguished perivascular spaces from lesions presumably ischemic. Perivascular spaces were further subdivided into lesions with diameters of ≤3 mm (small perivascular spaces) and >3 mm (large perivascular spaces). We calculated relative rates of events with Poisson models and hazard ratios with Cox proportional models. RESULTS: The Northern Manhattan Study participants who had MR imaging data available for review (n = 1228; 59% women, 65% Hispanic; mean age, 71 ± 9 years) were followed for an average of 9 ± 2 years. Participants in the highest tertile of the small perivascular space score had a higher relative rate of all deaths (relative rate, 1.38; 95% CI, 1.01-1.91), vascular death (relative rate, 1.87; 95% CI, 1.12-3.14), myocardial infarction (relative rate, 2.08; 95% CI, 1.01-4.31), any stroke (relative rate, 1.79; 95% CI, 1.03-3.11), and any vascular event (relative rate, 1.74; 95% CI, 1.18-2.56). After we adjusted for confounders, there was a higher risk of vascular death (hazard ratio, 1.06; 95% CI, 1.01-1.11), myocardial infarction (hazard ratio, 2.22; 95% CI, 1.12-4.42), and any vascular event (hazard ratio, 1.04; 95% CI, 1.01-1.08) with higher small perivascular space scores. CONCLUSIONS: In this multiethnic, population-based study, participants with a high burden of small perivascular spaces had increased risk of vascular events. By gaining pathophysiologic insight into the mechanism of perivascular space dilation, we may be able to propose novel therapies to better prevent vascular disorders in the population.

Utility of blood pressure genetic risk score in admixed Hispanic samples.

Hypertension is strongly influenced by genetic factors. Although hypertension prevalence in some Hispanic sub-populations is greater than in non-Hispanic whites, genetic studies on hypertension have focused primarily on samples of European descent. A recent meta-analysis of 200 000 individuals of European descent identified 29 common genetic variants that influence blood pressure, and a genetic risk score derived from the 29 variants has been proposed. We sought to evaluate the utility of this genetic risk score in Hispanics. The sample set consists of 1994 Hispanics from 2 cohorts: the Northern Manhattan Study (primarily Dominican/Puerto Rican) and the Miami Cardiovascular Registry (primarily Cuban/South American). Risk scores for systolic and diastolic blood pressure were computed as a weighted sum of the risk alleles, with the regression coefficients reported in the European meta-analysis used as weights. Association of risk score with blood pressure was tested within each cohort, adjusting for age, age2, sex and body mass index. Results were combined using an inverse-variance meta-analysis. The risk score was significantly associated with blood pressure in our combined sample (P=5.65 × 10-4 for systolic and P=1.65 × 10-3 for diastolic) but the magnitude of the effect sizes varied by degree of European, African and Native American admixture. Further studies among other Hispanic sub-populations are needed to elucidate the role of these 29 variants and identify additional genetic and environmental factors contributing to blood pressure variability in Hispanics.

Update on antiplatelet therapy for stroke prevention.

The high rates of mortality and long-term disability associated with ischemic stroke, coupled with its prevalence, necessitate good, long-term preventive strategies. Risk-factor management is effective for individuals with preclinical and clinical cerebrovascular disease. Patients suffering from a transient ischemic attack or stroke are particularly vulnerable to subsequent stroke. Most of these individuals are candidates for antiplatelet treatment to prevent a recurrence. Available antiplatelet therapies include aspirin, ticlopidine, and clopidogrel. The combination of low-dose aspirin plus extended-release dipyridamole has been shown to offer safe, effective antiplatelet therapy for appropriate patients. In the second European Stroke Prevention Study, the combination was found to be significantly more effective than either drug alone, at the cost of relatively few treatment-related adverse effects. This combination is currently recommended as one of the first-line treatments for stroke prevention after first transient ischemic attack or stroke.

Association of hyperandrogenemia and hyperestrogenemia with type 2 diabetes in Hispanic postmenopausal women.

OBJECTIVE: Accumulating evidence suggests that hyperandrogenemia may be a risk factor for coronary heart disease (CHD) in women. The present study was carried out to test the hypothesis that hyperandrogenemia is associated with type 2 diabetes in women and thus may contribute to the increased risk of CHD in women with type 2 diabetes. RESEARCH DESIGN AND METHODS: Sex hormones, sex hormone-binding globulin (SHBG), and risk factors for CHD were measured in 20 postmenopausal women with type 2 diabetes and in 29 control subjects. All of the diabetic and control subjects were Hispanic women aged >55 years who were not taking hormone replacement therapy lipid-lowering drugs, or insulin and who were otherwise randomly chosen from a cohort of stroke-free subjects from the Northern Manhattan Stroke Study RESULTS: Mean age, BMI, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, blood pressure, and smoking were not significantly different between cases and control subjects, but waist-to-hip ratio (WHR) was significantly higher in the diabetic subjects (P = 0.01). The mean levels of free testosterone (FT) (P = 0.01), dehydroepiandrosterone sulfate (P<0.04), and estradiol (P = 0.01) (controlled for WHR) were significantly higher in the diabetic subjects; with the statistical outliers removed, the testosterone (P = 0.05) and androstenedione (P = 0.002) levels (controlled for WHR) were also significantly higher in the diabetic subjects. The mean levels of estrone, cortisol, and SHBG were not significantly different. The results were similar in the 10 diabetic subjects treated with diet only Significant positive correlations (controlled for age and BMI) were observed between FT or testosterone and cholesterol, LDL cholesterol, and blood pressure. CONCLUSIONS: Postmenopausal Hispanic women with type 2 diabetes had both hyperandrogenemia and hyperestrogenemia, and testosterone or FT correlated positively with risk factors for CHD. Hyperandrogenemia may be a link between diabetes and CHD in women.

Gender differences in the risk of ischemic stroke associated with aortic atheromas.

BACKGROUND AND PURPOSE: Atherosclerotic plaque of the proximal portion of the aorta is associated with an increased risk of ischemic stroke in the elderly. Different cutoffs of plaque thickness have been used in the literature for risk stratification and have been applied to both men and women. However, the assumption that the relationship between plaque thickness and stroke risk is the same in the 2 genders has not been proven. The aim of this study was to evaluate whether the prevalence of different degrees of aortic plaque thickness differed in men and women with ischemic stroke. METHODS: We performed transesophageal echocardiography in 152 patients aged >59 years with acute ischemic stroke (76 men and 76 women) and in 152 control subjects of similar age (70 men and 82 women). Odds ratios (ORs) for ischemic stroke with 95% CIs for different plaque thickness definitions were calculated for the overall group and separately for men and women by logistic regression analysis after adjusting for age, arterial hypertension, and hypercholesterolemia. RESULTS: Aortic plaques >/=4 mm were significantly more frequent in men than in women (31.5% versus 20.3%, respectively; P:=0.025) and were associated with ischemic stroke in both men (adjusted OR 6.0, CI 2.1 to 16.8) and women (adjusted OR 3. 2, CI 1.2 to 8.8). However, plaques 3 to 3.9 mm in thickness had a significant association with stroke in women (adjusted OR 4.8, CI 1. 7 to 15.0) but not in men (adjusted OR 0.8, CI 0.2 to 3.0). Plaques <3 mm were not associated with a significantly increased stroke risk for either sex. CONCLUSIONS: Smaller aortic plaques are significantly associated with ischemic stroke in women but not in men. If the increased prevalence of smaller plaques in women is confirmed to be associated with increased risk for embolic stroke, different cutoff points may have to be adopted in men and women for risk stratification and for decisions regarding medical intervention.

Elevated white blood cell count and carotid plaque thickness : the northern manhattan stroke study.

BACKGROUND AND PURPOSE: Elevated leukocyte count has been associated with cardiovascular and cerebrovascular disease in several epidemiological studies. We sought to determine whether white blood cell count (WBC) is associated with carotid plaque thickness in a stroke-free, multiethnic cohort. METHODS: For this cross-sectional analysis, WBC was measured in stroke-free community subjects undergoing carotid duplex Doppler ultrasound. Maximal internal carotid plaque thickness (MICPT) was measured for each subject. Demographic and potential medical confounding factors were analyzed with linear and logistic regression to calculate the effect of quartile of WBC on MICPT. Odds ratios (ORs) and 95% confidence intervals (CIs) for the effect of quartile of WBC on MICPT >/=75th percentile were calculated. All analyses were stratified by race-ethnicity. RESULTS: The mean age of the 1422 subjects was 68.6+/-10.2 years; 40.0% were men; 24.4% were white, 46.9% Hispanic, and 26.7% black. Among Hispanics, compared with the lowest quartile of WBC, those in the highest quartile had significantly increased MICPT (mean difference=0.30 mm, P:=0.0086) after adjustment for age, sex, and other atherosclerotic risk factors. There was no significant increase for blacks or whites. The OR for MICPT >/=75th percentile (1.9 mm) was significantly increased for Hispanics (OR, 2.8; 95% CI, 1.4 to 5.6), marginally elevated for black non-Hispanics (OR, 1.6; 95% CI, 0.8 to 3.2), and not increased for white non-Hispanics (OR, 0.5; 95% CI, 0.2 to 1.1). CONCLUSIONS: Relative elevation in WBC is associated with carotid atherosclerosis, but this relationship differs by race-ethnicity. The association is strongest in Hispanics, intermediate in black non-Hispanics, and not present in white non-Hispanics in this population. Chronic subclinical infection or inflammation may account for this association.

Cost and outcome of mechanical ventilation for life-threatening stroke.

BACKGROUND AND PURPOSE: Hospital mortality rates of 50% to 90% have been reported for stroke patients treated with mechanical ventilation. These data have raised serious questions about the cost-effectiveness of this intervention. We sought to determine how often stroke patients are mechanically ventilated, identify predictors of 30-day survival among ventilated patients, and evaluate the cost-effectiveness of this intervention. METHODS: We identified mechanically ventilated patients in a population-based multiethnic cohort of 510 incidence stroke patients who were hospitalized between July 1993 and June 1996. Factors affecting 30-day survival were identified in a multiple logistic regression analysis. We calculated the cost per patient discharged alive, life-year saved, and quality-adjusted life-year saved using a zero-cost, zero-life assumption. RESULTS: Ten percent of patients (n=52) were mechanically ventilated. Thirty-day mortality was 65% overall and did not differ significantly by stroke subtype. Glasgow Coma Scale score on the day of intubation (P:<0.01) and subsequent neurological deterioration (P:=0.02) were identified as predictors of 30-day mortality. The cost (1996 US dollars) of hospitalization per patient discharged alive was $89 400; the cost per year of life saved was $37 600; and the cost per quality-adjusted life-year saved was $174 200. Functional status of most survivors was poor; at 6 months, half were severely disabled and completely dependent. In a worst-case scenario of quality of life preferences, mechanical ventilation resulted in a net deficit of meaningful survival. CONCLUSIONS: Two thirds of mechanically ventilated stroke patients die during their hospitalization, and most survivors are severely disabled. Survival is particularly unlikely if patients are deeply comatose or clinically deteriorate after intubation. In our multiethnic urban population, mechanical ventilation for stroke was relatively cost-effective for extending life but not for preserving quality of life.

Race-ethnic disparities in the impact of stroke risk factors: the northern Manhattan stroke study.

BACKGROUND AND PURPOSE: Stroke risk factors have been determined in large part through epidemiological studies in white cohorts; as a result, race-ethnic disparities in stroke incidence and mortality rates remained unexplained. The aim in the present study was to compare the prevalence, OR, and etiological fraction (EF) of stroke risk factors among white, blacks, and Caribbean Hispanics living in the same urban community of northern Manhattan. METHODS: In this population-based incident case-control study, cases (n=688) of first ischemic stroke were prospectively matched 1:2 by age, sex, and race-ethnicity with community controls (n=1156). Risk factors were determined through in-person assessment. Conditional logistic regression was used to calculate adjusted ORs in each race-ethnic group. Prevalence and multivariate EFs were determined in each race-ethnic group. RESULTS: Hypertension was an independent risk factor for whites (OR 1.8, EF 25%), blacks (OR 2.0, EF 37%), and Caribbean Hispanics (OR 2.1, EF 32%), but greater prevalence led to elevated EFs among blacks and Caribbean Hispanics. Greater prevalence rates of diabetes increased stroke risk in blacks (OR 1.8, EF 14%) and Caribbean Hispanics (OR 2.1 P<0.05, EF 10%) compared with whites (OR 1.0, EF 0%), whereas atrial fibrillation had a greater prevalence and EF for whites (OR 4.4, EF 20%) compared with blacks (OR 1.7, EF 3%) and Caribbean Hispanics (OR 3.0, EF 2%). Coronary artery disease was most important for whites (OR 1.3, EF 16%), followed by Caribbean Hispanics (OR 1.5, EF 6%) and then blacks (OR 1.1, EF 2%). Prevalence of physical inactivity was greater in Caribbean Hispanics, but an elevated EF was found in all groups. CONCLUSIONS: The prevalence, OR, and EF for stroke risk factors vary by race-ethnicity. These differences are crucial to the etiology of stroke, as well as to the design and implementation of stroke prevention programs.

Nontraumatic coma. Glasgow coma score and coma etiology as predictors of 2-week outcome.

In 1987 and 1988, we carried out a prospective study of patients older than 10 years with nontraumatic coma in the intensive care units of Columbia-Presbyterian Medical Center, New York, NY. Of 188 patients with Glasgow Coma Scale (GCS) determinations within 72 hours, 61% were dead or in persistent coma by 2 weeks from onset. Age, sex, and ethnicity did not influence outcome. The 2-week outcome for patients with initial GCS of 3 to 5 was 14.8% awake; 85.2% were dead or in persistent coma. For the GCS 6 to 8 group, 53.1% were awake and 46.9% were dead or in persistent coma. Hypoxic or ischemic coma had the worst 2-week outcome (79% dead or comatose); coma caused by metabolic disease or sepsis (68%), focal cerebral lesions (66%), and general cerebral diseases (55%) were intermediate, while drug-induced coma had a favorable outcome (27% dead or comatose). The independent predictors of 2-week outcome were the first GCS and drug-induced coma. The predicted probability of waking at 2 weeks was eight times better for drug-induced coma than other causes when GCS was held constant. Patients with an initial GCS score of 6 to 8 were seven times more likely to waken than those with a score of 3 to 5. The motor subscore alone was a significant independent predictor of 2-week outcome. Modification of coma score to include etiology may give more accurate predictions of 2-week outcome after nontraumatic coma.

Dissociated vertical nystagmus and internuclear ophthalmoplegia from a midbrain infarction.

We describe a patient with a dissociated vertical nystagmus and an internuclear ophthalmoplegia. The vertical nystagmus consisted of a left downward nystagmus with a synchronous right intorting nystagmus when the patient looked down and to the left. This rare type of nystagmus has been described both in isolation and in association with an internuclear ophthalmoplegia. Previous authors postulated a lesion in the midbrain in the region of the medial longitudinal fasciculus. In our patient, a discrete midbrain infarction was demonstrated on magnetic resonance imaging in the hypothesized location, thus providing supportive anatomical evidence for a vertical gaze coordination pathway in the region of the medial longitudinal fasciculus.

Wallenberg's lateral medullary syndrome. Clinical-magnetic resonance imaging correlations.

OBJECTIVE: To correlate clinical and radiologic findings in patients with lateral medullary infarction. DESIGN: Case series with "blinded" evaluation of brain imaging. SETTING: Hospitalized and ambulatory patients at the Neurological Institute of New York (NY). PATIENTS: Thirty-three consecutive patients with lateral medullary syndrome were evaluated by the Stroke Center between 1983 and 1989. RESULTS: Ataxia (70%), numbness either of the ipsilateral face or of the contralateral body (64%), vertigo (51%), and dysphagia (51%) were the most frequent symptoms at onset. Eleven patients had ocular symptoms (diplopia or blurred vision). Horner's syndrome was found in 91%, ipsilateral ataxia in 85%, and contralateral hypalgesia in 85%. Nystagmus (61%) and facial weakness (42%) were less frequent. Head computed tomography was abnormal only when a cerebellar infarction was present (three cases). Magnetic resonance imaging, obtained in 22 cases, was normal in two; a lateral medullary infarction alone was present in 12, and a lesion extending beyond the lateral medulla was found in eight. No correlation was noted between facial weakness or ocular symptoms and infarction extending beyond the lateral medullary region. Vertebral artery disease was confirmed by vascular imaging or insonation studies in 73% of patients. CONCLUSIONS: The triad of Horner's syndrome, ipsilateral ataxia, and contralateral hypalgesia will clinically identify patients with lateral medullary infarction. Facial weakness and ocular symptoms are frequent and do not necessarily imply that the infarction extends beyond the lateral medulla. Cerebellar infarcts only infrequently accompany lateral medullary syndrome, suggesting that most of the posterior inferior cerebellar artery territory is spared, despite the high frequency of vertebral artery occlusion.

Thalamic stroke. Presentation and prognosis of infarcts and hemorrhages.

Thalamic strokes in 62 patients selected from the Stroke Data Bank were studied to determine differences among 18 infarctions (INF), 23 localized hemorrhages (ICH), and 21 hematomas with ventricular extension (IVH). Stupor or coma at onset occurred more frequently in the IVH (62%) than in the INF (6%) or ICH (13%) groups and was reflected in significantly lower median Glasgow Coma Scores in the IVH group (7) than in the INF (15) and ICH (14) groups. Although ocular movements were more frequently abnormal in the IVH group compared with the ICH and INF groups, no significant differences were found in the frequency of motor or sensory deficits. Among the 62 strokes, 32 had restricted lesions of the posterolateral (n = 9), anterior (n = 3), paramedian (n = 7), and dorsal (n = 13) portions of the thalamus. Differences in consciousness and in motor, sensory, and oculomotor deficits were found among the topographic subgroups. Stroke-related deaths occurred in 52% of IVH cases, 13% of ICH cases, and no cases of INF. Median lesion volume as detected with computed tomography was greater in hemorrhages (INF, 2 cm3; ICH, 10 cm3; IVH, 16 cm3), with mortality related to increasing hematoma size. Coma, Glasgow Coma Score lower than 9, weakness score greater than 15 of a possible 30, abnormal ocular movements, and fixed pupils were also associated with stroke-related mortality. We conclude that the initial neurologic syndrome does not discriminate infarcts from intrathalamic hemorrhages. Ventricular extension, however, causes significantly more severe deficits and higher mortality.

Risk factors and outcomes for ischemic stroke.

Stroke continues to have a great impact on public health in the United States. Stroke is frequent, recurring, and is more often disabling than fatal. The annual incidence of new strokes in the United States is nearly one half million, with over 3 million stroke survivors alive today. Identifying risk factors for initial ischemic stroke, as well as characterizing the determinants of outcome (stroke recurrence and mortality) after ischemic stroke, is the basis for stroke prevention strategies. Modifiable and nonmodifiable risk factors for ischemic stroke have been identified and include age; gender; race/ethnicity; heredity; hypertension; cardiac disease, particularly atrial fibrillation; diabetes mellitus; hypercholesterolemia; cigarette smoking; and alcohol abuse. New risk factors, such as hypercoagulable states and patient foramen ovale, are currently being investigated. Follow-up studies have quantified case-fatality rates, early recurrence risk, and long-term mortality and recurrence risks. Despite advances in stroke prevention strategies and treatments, stroke recurrence is still the major threat to any stroke survivor. A major goal set by the Public Health Service in its National Health Promotion and Disease Prevention Objectives for the year 2000 is "to reduce stroke deaths to no more than 20 per 100,000." Part of this can be achieved if the risk of stroke recurrence is reduced. However, the frequency and determinants of stroke recurrence are poorly understood. Data from epidemiologic studies can help identify risk factors and outcomes after ischemic stroke, as well as the selection of high-risk individuals for focused risk-factor modification. Current information on these topics is discussed.

Identifying patient populations at high risk for stroke.

Although the treatment of acute ischemic stroke has improved, the greatest reductions in stroke mortality and morbidity may possibly be achieved through more effective prevention strategies. Toward this goal, risk factor profiles for initial and recurrent stroke have been identified through longitudinal epidemiologic studies. Nonmodifiable risk markers for initial ischemic stroke include age, sex, family history, and race/ethnicity. Modifiable risk factors for first ischemic stroke include hypertension, cardiac disease (particularly atrial fibrillation), diabetes, hyperlipidemia, cigarette smoking, alcohol abuse, physical inactivity, asymptomatic carotid stenosis, and transient ischemic attack. As improved acute treatments increase survival after a first stroke, the threat of increased morbidity from stroke recurrence will have greater significance. The risk and specific determinants of early and late stroke recurrence are the subject of ongoing investigations. Age, stroke syndrome, hypertension, cardiac disease (particularly congestive heart failure), hyperglycemia, and alcohol abuse have been identified as predictors of late stroke recurrence. Now that many risk factors are established, greater emphasis should be placed on identifying high stroke-risk patient populations for intensive risk factor modification and antithrombotic treatments. Better understanding and management of stroke risk factors will undoubtedly improve our ability to prevent first and recurrent ischemic stroke.

Newer risk factors for stroke.

Stroke places a tremendous burden on health resources throughout the world. Improved detection and modification of risk factors could reduce the impact of this disease. Important non-modifiable risk factors for ischemic stroke include age, gender, ethnicity, and heredity. Modifiable risk factors include hypertension, cardiovascular disease, diabetes, hyperlipidemia, asymptomatic carotid stenosis, cigarette smoking, and alcohol abuse. Data from the Northern Manhattan Stroke Study provide new insights into these stroke risk factors. In this study, African-Americans and Hispanics had a greater incidence of stroke, with almost a twofold increase compared with Caucasians. The protective effect of physical activity and moderate alcohol consumption was confirmed and further established as modifiable risk factors. The independent effects of lipids, apolipoproteins, and lipoprotein were also clarified. High-density lipoprotein was shown to be protective against ischemic stroke (particularly atherosclerotic stroke subtypes). Conversely, lipoprotein-a increased the risk for stroke. The ratio of apolipoprotein b to apolipoprotein a-1 was shown to be associated with carotid atheroma. In addition, newer risk factors, including homocysteine and chronic infection (Chlamydia pneumoniae and periodontal disease), are being studied as predictors of ischemic stroke. With these recent advances in the understanding of risk factors, the ability to detect or modify the risk for ischemic stroke should lead to a substantial reduction in the number of people killed or disabled by stroke each year.