Establishment of the Thai version of National Institute of Health Stroke Scale (NIHSS) and a validation study

BACKGROUND

The National Institute of Health Stroke Scale (NIHSS) is a well validated stroke severity assessment scale. The scale is used to assess neurological deficits, progression and degree of recovery in acute stroke settings. To date, no Thai version exists.

OBJECTIVE

This study aimed to adapt and validate a Thai version of the NIHSS (NIHSS-T).

MATERIAL AND METHOD

A cross-cultural adaptation of the NIHSS was developed according to the methods recommended by the International Quality of Life Assessment Project Group. Forward and backward translations were performed. A final version of the NIHSS-T was validated against initial MRI infarction volume and modified Rankin Scale (mRS) at 3 months in a consecutive series of acute stroke patients. The patients were prospectively evaluated by 3 different types of health care providers: 2 stroke fellows, 2 internists, and 2 stroke nurses. Mean NIHSS-T scores from all raters were used in the analysis.

RESULTS

The study included 32 acute ischemic stroke patients with a mean age (+/- SD) of 64.53 +/- 14.97 years of age. Men comprised 71.9%. Mean NIHSS-T score (+/- SD) was 7.49 +/- 7.02. Intra-observer reliability demonstrated a high agreement with an intraclass correlation (ICC) of 0.98, 0.98, 0.96, 0.98, 0.90 and 0.98 for 2 stroke fellows, 2 internists and 2 stroke nurses respectively. Inter-observer reliability between 6 raters was excellent, i.e.; ICC, 0.99 (0.98, 0.99). Spearman rank correlation coefficients between the initial NIHSS-T score versus initial MRI lesion volume and mRS at 3 months were 0.53 and 0.69 with a p-value of 0.002 and < 0.001 respectively.

CONCLUSION

The Thai version of NIHSS is valid for assessing acute stroke severity. The scale is also reliable when administered in a Thai-speaking setting by trained healthcare professionals.

[Complex analysis of genetic predisposition to ischemic stroke in Russians]

Carriage frequencies of alleles and genotypes of 10 functionally important single nucleotide polymorphisms that are located in genes FGA, FGB, APOE, LPL, ACE and CMA1 were analyzed in the ischemic stroke (IS) patients of Russian ethnic descent and in the control group of the same ethnic descent and of similar gender and age. Comparison between patients and control group revealed no significant differences in frequencies of individual alleles and genotypes for all the polymorphic loci studied. However, complex analysis of genetic predisposition using APSampler algorithm revealed carriage of allele (-491A) APOE as a predisposing factor for IS (p = 0.044, OR 3.8, 95% CI 1.0-15.1). Accordingly, carriage of genotype (-491T/T) APOE was associated with resistance to IS (p = 0.044, OR 0.26, 95% CI 0.07-1.0). The allele -249C FGB carriage addition to this genotype enhances its protective properties, p-value of the combination is 2-fold lower than that of the genotype (-491T/T) APOE (OR 0.17, 95% CI 0.04-0.8). Two more protective combinations were identified: biallelic (-427C) APOE + (1595G) LPL and triallelic (-491C) APOE + (1595G) LPL + (-1903G) CMAI (in both cases p = 0.0052, OR 0.18, 95% CI 0.05-0.66). Overall, involvement in formation of the risk of IS development in Russians was evidenced for alleles of four genes: APOE, FGB, LPL and CMA1, where APOE gene involvement was evidenced for alleles of two polymorphic loci, -491T and -427C. Linkage analysis suggested that involvement of these loci in insusceptibility to IS is mutually independent.

Lack of association between the paraoxonase 1 Q/R192 single nucleotide polymorphism and stroke in a Chinese cohort

BACKGROUND

Serum paraoxonase (PON1) is an HDL-associated esterase that hydrolyzes products of lipid peroxidation and prevents the oxidation of LDL. Paraoxonase 1 (PON1) was implicated in susceptibility to stroke in previous studies. We investigated the correlation between the paraoxonase Gln-Arg 192 polymorphism (PON1Q/R192) and stroke including cerebral hemorrhage and cerebral infarction.

METHOD

The association between the paraoxonase Gln-Arg 192 polymorphism (PON1Q/R192) and stroke was investigated in 1019 subjects, which involved 305 cases with cerebral hemorrhage, 375 cases with cerebral infarction and 339 healthy controls.

RESULTS

The PON1Q/R192 genotype distribution in the cerebral hemorrhage group was QQ13.1%, QR48.2% and RR38.7% and in the cerebral infarction group was QQ13.6%, QR44.0% and RR42.4% respectively. There was no significant difference in PON1Q/R192 allele and genotype distribution between the patient group and the control group (P > 0.05). The PON1 polymorphism was not associated with cerebral hemorrhage or infarction.

CONCLUSION

Our study suggests that serum paraoxonase (PON1) is not associated with cerebral hemorrhage or infarction, although it is a lipolactonase which is associated with HDL-apolipoprotein A-I (HDL-apoA-I) and plays a role in the prevention of atherosclerosis.

ACE I/D polymorphism in Korean patients with ischemic stroke and silent brain infarction

OBJECTIVES

Angiotensin-converting enzyme (ACE) polymorphism may play a role in stroke and silent brain infarction (SBI) susceptibility, but the results among the populations studied to date have not been consistent. Thus, we investigated the association between ACE genotypes and ischemic stroke and SBI in Korean patients.

SUBJECTS AND METHODS

DNA samples from 237 stroke patients, 264 SBI patients and 234 age-matched controls were amplified using polymerase chain reaction to detect the ACE ins/del (I/D) polymorphism. Genotype was determined by the presence of a 490-bp band (I allele) or a 190-bp band (D allele) in agarose gel electrophoresis.

RESULTS

Odds ratios of the I/D and D/D genotypes and the overall (I/D + D/D) for the I/I genotype were significantly different between stroke patients and normal controls. However, there was no significant difference between patients with SBI and controls.

CONCLUSIONS

This study is the first report of a significant association between ACE polymorphism and ischemic stroke in the Asian population. Although no consistent associations have been found between ACE polymorphism and stroke in the populations studied to date, the ACE polymorphism may be a genetic determinant of ischemic stroke, at least in Korean patients.

Poor outcomes in Hispanic and African American patients after acute ischemic stroke: influence of diabetes and hyperglycemia

BACKGROUND

Stroke is a leading cause of mortality and disability in the United States, and it disproportionately affects vulnerable populations, such as Hispanics and African Americans. We compared the prevalence of stroke risk factors, in-hospital treatment of hyperglycemia, and outcome among different ethnic groups after acute ischemic stroke (AIS).

METHODS

Retrospective study of patients with AIS treated at an urban tertiary care center. Hispanic, African American, and White patients were compared by demography, illness severity, co-morbid conditions, degree of treatment of hyperglycemia, and outcome. Data were analyzed by using t testing, chi2 testing, and analyses of variance, as appropriate.

RESULTS

960 cases were reviewed (68% African American, 13% Hispanic, 11% White, 8% other). Hispanic and African American patients were younger than White patients. More White patients had atrial fibrillation (26.7%) than did Hispanic (9.5%) or African American patients (6.6%, P<.001). Hispanic and African American patients had higher rates of hypertension (76%, 77%) than did White patients (55%, P<.001), and more Hispanic patients had diabetes (58%) than did either African American (37%) or White patients (27%, P<.001). Hispanic patients had higher blood glucose levels than did African American or White patients at baseline, 24 hours, and 48 hours after admission (P<.05). Diabetic Hispanic patients had higher in-hospital mortality rates (8.0%) than did diabetic non-Hispanic patients (2.5%, P=.03).

CONCLUSION

The incidence of stroke risk factors (atrial fibrillation, diabetes mellitus, and hypertension) differs between urban African American, Hispanic, and White patients. Hyperglycemia, a known independent predictor of mortality after stroke, is more likely to be present and persist during hospitalization in Hispanic patients than in African American and White patients. These disparities may explain the disproportionate mortality rates among Hispanic and African American and White patients after AIS. Focusing prevention and treatment towards hypertension, diabetes, and hyperglycemia may reduce racial/ethnic disparities and improve mortality and disability after acute ischemic stroke.

[Comparison between German and Turkish descent in ischemic stroke. Risk factors, initial findings, rehabilitative therapy, and social consequences]

BACKGROUND

Until now no data has been available on possible specific features of the Turkish minority in Germany with respect to stroke.

PATIENTS AND METHODS

We compared 20 Turkish stroke patients with matched German controls analyzing risk factors, findings at admission, rehabilitative treatments, and psychosocial aspects.

RESULTS

In the Turkish group the interval between onset of symptoms and admission was longer (532 min vs 255 min, P < 0.01). All other findings during acute treatment and rehabilitation were comparable. At follow-up after 22 months, the Barthel index was 90 for the Turks and 100 for the Germans. The Turkish patients reported more consultations with physicians than their German counterparts (68 vs 12 per year, P < 0.01). Scores for quality of life and outcome did not differ. The Turkish patients more frequently required care and had a higher degree of disability.

CONCLUSIONS

Turkish stroke patients have a longer time to admission. Risk factors, findings at admission, and treatment in the acute phase and rehabilitation are comparable. Several findings point towards a different health behavior. These results highlight the need for specific education of the Turkish population in Germany.

Elevated lipoprotein (a) and apolipoprotein B to AI ratio in South Asian patients with ischaemic stroke

BACKGROUND

Stroke is a continuing cause of excess cardiovascular disease (CVD) mortality amongst migrants from the Indian subcontinent (South Asians) living in Britain. However, little is known about the dyslipidaemia associated with stroke in South Asians. In particular, the highly atherogenic lipoprotein (a) [Lp(a)] and high apolipoprotein (Apo) B to AI ratio are emerging risk factors for CVD.

METHODS

Using a case-control study, we investigated features of the dyslipidaemia in South Asian patients with stroke compared with South Asian subjects with no history of clinically detectable stroke. We studied 55 consecutive South Asian patients with ischaemic stroke (confirmed on computerised scan of the brain) and 85 controls.

RESULTS

The stroke patients were significantly older than controls (65.2 vs. 59.8 years, p = 0.001), but were similarly matched for male gender (63.6 vs. 61.2%), smoking habit (20.7 vs. 18.1%) and presence of type 2 diabetes (25.5 vs. 19.3%). There were no differences between serum total cholesterol (p = 0.07) and high-density lipoprotein cholesterol (p = 0.08) between the groups, but stroke patients had higher serum triglycerides (p = 0.005). Mean [95% confidence interval (CI)] Apo B to AI ratio was higher amongst stroke patients [1.0 (0.9-1.0) vs. 0.7 (0.7-0.75), p < 0.001]. Similarly, geometric mean serum Lp(a) was significantly higher (p = 0.037) in stroke patients [19.9 mg/dl (14.0-28.5)] vs. controls [15.1 mg/dl (11.4-20.1)]. On logistic regression, stroke was independently associated with age and Apo B to AI ratio (p < 0.01).

CONCLUSION

The present study suggests that Lp(a) and the Apo B to AI ratio are associated with ischaemic stroke in South Asians. A prospective analysis is needed to elucidate the role of Lp(a), Apo B and AI as risk factors for ischaemic stroke in this population, as well as the effects of intervention.

Angiotensinogen gene polymorphism as a risk factor for ischemic stroke

While gene polymorphism for angiotensinogen (AGT) is reported to contribute to the regulation of blood pressure and salt sensitivity, its effect on the risk of ischemic stroke remains controversial. We hypothesized that polymorphism of the AGT gene could be a risk factor for ischemic stroke. Major clinical risk factors and the AGT gene M235T polymorphism were examined in 147 consecutive stroke patients and 133 healthy age-matched controls. All patients were categorized into four stroke types (single lacuna, multiple lacunae, large-artery atherosclerosis and branch atheromatous disease in brainstem) and two vascular groups (large and perforating arterial lesions). The AGT gene M allele significantly increased the risk of single lacuna, multiple lacunae and small arterial lesions, in male patients (p=0.029, 0.031 and 0.026, respectively). Synergistic effects of the AGT gene polymorphism and clinical risks were not observed. In conclusion, AGT M allele may present a risk of lacunar infarctions in Japanese men, independent of hypertension.

Intracranial large artery disease among OCSP subtypes in ethnic South Asian ischemic stroke patients

The site of vascular stenosis correlates well with the Oxfordshire Community Stroke Project (OCSP) classification among Caucasians, but not among ethnic Chinese patients. We prospectively studied 205 consecutive ethnic South Asian ischemic stroke patients to investigate the prevalence of intracranial large artery disease determined by transcranial color-coded doppler and magnetic resonance angiography among OCSP subtypes. The distribution of OCSP subtypes was 7% total anterior circulation infarction (TACI), 17% partial anterior circulation infarction (PACI), 14% posterior circulation infarction (POCI) and 62% lacunar infarction (LACI). Significant intracranial large artery disease was common among all OCSP subtypes; 79% with TACI, 47% PACI, 65% POCI and 44% LACI. This is similar to ethnic Chinese data and is likely due to the predominance of intracranial disease over extracranial disease. Clinical axioms using OSCP subtypes based on Caucasian data may be misleading if applied to ethnic South Asians.

Emergency Department Arrival Times after Acute Ischemic Stroke During the 1990s

INTRODUCTION

Only 8% of ischemic stroke (IS) patients are eligible for rt-PA, and the largest exclusion criterion is delayed time of presentation to the ED. We sought to investigate whether patients are arriving to the ED more quickly in 1999 than in 1993/94 within our large biracial population of 1.3 million.

METHODS

Using ICD-9 codes 430-436, we ascertained all stroke events that presented to a local ED within our population in 7/93-6/94 and again in 1999. Times were recorded as documented in the medical record.

RESULTS

There were 1,792 IS patients that presented to an ED in 1993/94 and 1,973 in 1999. The percentage of patients with documented times arriving in under 3 h improved slightly in 1999 (26% vs. 23% in 93/94, P = 0.03), however, the percentage arriving in under 2 h did not. Blacks significantly improved in arrivals under 3 h: 26% in 1999 compared to 17% in 1993/94 (P = 0.01), while whites did not (26% vs. 25%, P = 0.29). In 1999, only 9% of patients arrived from 3-8 h after symptom onset, the large majority of times were either estimated, unknown, or >8 h.

DISCUSSION

We found only marginal improvement in arrival times during the 1990s. In our population, blacks improved in early arrival after symptom onset, while whites did not. Very few patients arrive 3-8 h after onset; therefore expansion of the acute treatment time window to 8 h is unlikely to dramatically affect acute treatment of ischemic stroke.

Low-molecular-weight heparin compared with aspirin for the treatment of acute ischaemic stroke in Asian patients with large artery occlusive disease: a randomised study

BACKGROUND

Acute stroke patients with large artery occlusive disease (LAOD) have a distinct pathophysiology and may respond differently to anticoagulation treatments. We compared the efficacy of a low-molecular-weight heparin (LMWH), nadroparin calcium, with aspirin in Asian acute stroke patients with LAOD.

METHODS

Acute ischaemic stroke patients with onset of symptoms less than 48 h and LAOD (diagnosed by transcranial doppler imaging, carotid duplex scan, or magnetic resonance angiography) were recruited. Patients were randomly assigned to receive either subcutaneous nadroparin calcium 3800 anti-factor Xa IU/0.4 mL twice daily or oral aspirin 160 mg daily for 10 days, and then all received aspirin 80-300 mg once daily for 6 months. This study is registered at www.strokecenter.org/trials (number 493).

FINDINGS

Among 603 patients recruited, 353 (180 LMWH, 173 aspirin) had LAOD (300 had intracranial LAOD only, 42 had both intracranial and extracranial disease, and 11 had extracranial disease only). The proportion of patients with good outcomes at 6 months (Barthel index >or=85) was 73% in the LMWH group and 69% in the aspirin group (absolute risk reduction 4%; 95% CI -5 to 13). Analysis of prespecified secondary outcome measures showed a benefit in outcome for LMWH versus aspirin on the modified Rankin scale dichotomised at 0-1 (odds ratio 1.55, 95% CI 1.02-2.35). Haemorrhagic transformation of infarct and severe adverse events were similar in both groups. Post-hoc analyses of patients without LAOD, and all treated patients, showed similar proportions with a good outcome in aspirin and LMWH groups (78%vs 79% and 73%vs 75%, respectively).

INTERPRETATION

Overall, the results do not support a significant benefit of LMWH over aspirin in patients with LAOD. The benefits indicated in most outcome measures warrant further investigation into the use of anticoagulation for acute stroke in patients with large artery atherosclerosis, particularly in intracranial atherosclerosis.

Elective and isolated carotid endarterectomy: health disparities in utilization and outcomes, but not readmission

BACKGROUND

Carotid endarterectomy (CEA) has been shown to decrease future ischemic stroke risk in selected patients. However, clinical trials did not examine the risk-benefit ratio for nonwhites, who have a greater ischemic stroke risk than whites. In general, few studies have examined the effects of race on CEA use and complications, and data on race and CEA readmission are lacking.

METHODS

This study used administrative data for patients discharged from California hospitals between January 1 and December 31, 2000. Selection criteria of cases included: ICD-9 principal procedure code 38.12, principal diagnostic code 433 and diagnosis-related group 5. There were 8,080 white and 1196 nonwhite patients (228 blacks, 643 Hispanics, 325 Asians/Pacific Islanders) identified that underwent an elective and isolated CEA. For both groups, CEA rates were compared. Logistic regression was used to examine the independent effects of race on in-hospital death and stroke, as well as CEA readmission.

RESULTS

Rates of CEA use were more than three times greater for whites than nonwhites, although nonwhites were more likely to have symptomatic disease. For all patients, the complication rate was 1.9%. However, the odds of in-hospital death and stroke were greater for nonwhites than whites, but after adjustment for patient and hospital factors, these differences were only significant for stroke (OR = 1.7, P = 0.013). For both outcomes, the final models had good predictive accuracy. Overall, CEA readmission risk was 7%, and no significant racial differences were observed (P = 0.110).

CONCLUSIONS

The data suggest that CEA is performed safely in California. However, nonwhites had lower rates of initial CEA use but higher rates of in-hospital death and stroke than whites. Racial differences in stroke risk persisted after adjustment for patient and hospital factors. Finally, this study found that despite significant racial disparities in initial CEA use, whites and nonwhites were similar in their CEA readmission rates. These findings may suggest that screening initiatives are lacking for nonwhites, which may increase their risk for poorer outcomes.

Polymorphism of apolipoprotein E (APOE) and lipoprotein lipase (LPL) genes and ischaemic stroke in individuals of Yakut ethnicity

There is evidence that most forms of ischaemic stroke (IS) result from synergistic effects of the modifiable predisposing factors and multiple genes. In the present work, we report results of case-control study of IS association with apolipoprotein E gene (APOE) (promoter and coding polymorphisms) and lipoprotein lipase gene (LPL) (presence/absence of a HindIII cutting site). We studied 107 unrelated patients of Yakut ethnicity (69 men and 38 women, mean age 58.4+/-11.5 years) with first-ever IS in carotid/middle cerebral artery regions. The control group included 101 subjects of the same ethnicity (61 men and 40 women, mean age 57.6+/-11.6 years) free of clinically detectable cerebrovascular disease, and without any history of stroke. A positive association of IS with APOE -427T allele (p=0.0012, OR=3.99) and -427T/T genotype (p=0.0005, OR=4.96) and a negative association with -427C allele (p=0.0012, OR=0.25), -427T/C genotype (p=0.0003, OR=0.18), epsilon2 allele (p=0.018, OR=0.35), epsilon2/3 genotype (p=0.017, OR=0.28) and -491A/-427C/epsilon2 haplotype (p=0.0026, OR=0.18) were observed. For atherothrombotic subgroup the same allele and genotype associations were found plus association with APOE -491A allele (p=0.026, OR=3.98). No reliable IS associations were found with LPL T+495G (HindIII) polymorphism. An association of APOE promoter polymorphisms (A-491T, T-427C) with an IS is shown in our study for the first time. Our study provides evidence for the role of APOE gene as a prognostic genetic marker for IS, especially for its atherothrombotic subtype.

Genetics of ischaemic stroke among persons of non-European descent: a meta-analysis of eight genes involving approximately 32,500 individuals

BACKGROUND

Ischaemic stroke in persons of European descent has a genetic basis, but whether the stroke-susceptibility alleles, the strength of any association, and the extent of their attributable risks are the same in persons of non-European descent remains unanswered. Whether ethnicity itself has a relevant or substantial contribution on those effect estimates is controversial. Comparative analyses between the ethnic groups may allow general conclusions to be drawn about polygenic disorders.

METHODS AND FINDINGS

We performed a literature-based systematic review of genetic association studies in stroke in persons of non-European descent. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for each gene-disease association using fixed and random effect models. We further performed a comparative genetic analysis across the different ethnic groups (including persons of European descent derived from our previous meta-analysis) to determine if genetic risks varied by ethnicity. Following a review of 500 manuscripts, eight candidate gene variants were analysed among 32,431 individuals (12,883 cases and 19,548 controls), comprising mainly Chinese, Japanese, and Korean individuals. Of the eight candidate genes studied, three were associated with ischaemic stroke: the angiotensin I converting enzyme (ACE) insertion/deletion (I/D) polymorphism with a mean OR of 1.90 (95% CI 1.23-2.93) in the Chinese and 1.74 (95% CI 0.88-3.42) in the Japanese; the summary OR for the C677T variant of 5,10-methylenetetrahydrofolate reductase (MTHFR) was 1.18 (95% CI 0.90-1.56) in Chinese and 1.34 (95% CI 0.87-2.06) in Koreans; and the pooled OR for the apolipoprotein E (APOE) gene was 2.18 (95% CI 1.52-3.13) in Chinese and 1.51 (95% CI 0.93-2.45) in Japanese. Comparing the commonly investigated stroke genes among the Asian groups against studies in persons of European descent, we found an absence of any substantial qualitative or quantitative interaction for ORs by ethnicity. However, the number of individuals recruited per study in the studies of persons of non-European descent was significantly smaller compared to studies of persons of European descent, despite a similar number of studies conducted per gene.

CONCLUSIONS

These data suggest that genetic associations studied to date for ischaemic stroke among persons of non-European descent are similar to those for persons of European descent. Claims of differences in genetic effects among different ethnic populations for complex disorders such as stroke may be overstated. However, due to the limited number of gene variants evaluated, the relatively smaller number of individuals included in the meta-analyses of persons of non-European descent in stroke, and the possibility of publication bias, the existence of allele variants with differential effects by ethnicity cannot be excluded.

Defining cause of death in stroke patients: The Brain Attack Surveillance in Corpus Christi Project

Stroke mortality is an important national health statistic and represents a frequent endpoint for epidemiologic studies. Several methods have been used to determine cause of death after stroke, but their agreement and reliability are unknown. Two hundred consecutive deaths of transient ischemic attack or ischemic stroke patients were identified (January 2000-September 2001) from an ongoing population-based stroke surveillance study in Texas, The Brain Attack Surveillance in Corpus Christi Project. Two neurologists independently recorded the cause of death based on two methods: 1) determining the underlying cause of death as defined by the World Health Organization, and 2) determining whether the death was stroke related. Kappa statistics with 95% confidence intervals were calculated by comparing agreement between methods within reviewers and between reviewers within methods. Agreement between the two cause-of-death-determination methods for each neurologist was 0.41 (95% confidence interval (CI): 0.31, 0.51) and 0.47 (95% CI: 0.38, 0.58), respectively. Agreement between neurologists for the underlying-cause-of-death method was 0.46 (95% CI: 0.32, 0.60); for the stroke-related method, it was 0.63 (95% CI: 0.52, 0.75). Accurate, reliable determinations of cause of death after stroke/transient ischemic attack are not currently feasible. More research is needed to identify a reliable process for coding cause of death from stroke.

Neighborhood environment and risk of ischemic stroke: the brain attack surveillance in Corpus Christi (BASIC) Project

The authors explored whether neighborhood-level characteristics are associated with ischemic stroke and whether the association differs by ethnicity, age, and gender. Using data from the Brain Attack Surveillance in Corpus Christi Project (January 2000-June 2003), they identified cases of ischemic stroke (n = 1,247) from both hospital and out-of-hospital sources. Census tracts served as proxies for neighborhoods, and neighborhood socioeconomic status scores were constructed from census variables (higher scores represented less disadvantage). In Poisson regression analyses comparing the 90th percentile of neighborhood score with the 10th, the relative risk of stroke was 0.49 (95% confidence interval (CI): 0.41, 0.58). After adjustment for age, gender, and ethnicity, this association was attenuated (relative risk (RR) = 0.79, 95% CI: 0.63, 1.00). There was no ethnic difference in the association of score with stroke (p for interaction = 0.79). Significant effect modification was found for age (p for interaction < 0.001) and gender (p for interaction = 0.04), with increasing scores being protective against stroke in men and younger persons. Associations were attenuated after adjustment for education (men: RR = 0.77, 95% CI: 0.55, 1.07; persons aged <65 years: RR = 0.65, 95% CI: 0.41, 1.02). Neighborhood characteristics may influence stroke risk in certain gender and age groups. Mechanisms for these associations should be examined.

African American women have poor long-term survival following ischemic stroke

OBJECTIVE

To determine racial and gender differences in long-term survival following ischemic stroke in a well-defined cohort of patients.

METHODS

We analyzed the prospectively collected data from a randomized, placebo-controlled trial in patients with ischemic stroke presenting within 3 hours of symptom onset. We determined the effect of race and gender on 1-year survival ascertained by serial follow-ups using Kaplan-Meier analysis. Multivariate analysis was performed adjusting for age, initial NIH Stroke Scale (NIHSS) score, use of thrombolysis, time to randomization, stroke etiology, and other cardiovascular risk factors.

RESULTS

Of the 547 patients with ischemic stroke, the 1-year survival (percentage +/- SE) for African American women (63 +/- 6%) was lower than white women (73 +/- 4%), African American men (79 +/- 4%), and white men (75 +/- 3%). Among the 209 patients younger than 65 years, the 1-year survival was prominently lower for African American women (66 +/- 8%) vs white women (87 +/- 5%), African American men (83 +/- 5%), and white men (89 +/- 3%). In the Cox proportional hazard analysis, African American women had a significantly higher rate of 1-year mortality (relative risk 2.1, 95% CI 1.2 to 3.5) after adjusting for all potential confounders except diabetes mellitus. After adjustment for diabetes mellitus, the difference became insignificant, although a 70% greater risk of 1-year mortality was still observed.

CONCLUSIONS

Compared with whites and men, African American women have a lower 1-year survival following ischemic stroke.

Why are eligible thrombolysis candidates left untreated?

BACKGROUND

Despite proven efficacy, thrombolytics are used in a minority of eligible candidates. Because some of the exclusion criteria are vague, relying on documented contraindications could disguise biases in usage. This study sought to identify barriers to tissue-type plasminogen activator (tPA) treatment among eligible patients with acute ischemic stroke.

METHODS

The study prospectively identified all patients with an initial diagnosis of ischemic stroke arriving within 2.5 hours of symptom onset at 11 hospitals participating in the Centers for Disease Control and Prevention-sponsored California Acute Stroke Prototype Registry during two 3-month periods in 2002 and 2003. Potential risk factors for nontreatment with thrombolytics among patients categorized as eligible were examined, based on directly documented contraindications. Analyses were repeated after reclassification of eligibility based on record review.

RESULTS

Of 625 patients with ischemic stroke, 126 (20%) arrived at the emergency department within 2.5 hours of symptom onset. Based on direct documentation, 72 (11.5% of all patients; 57% of in-time arrivals) were eligible for thrombolysis; 32 (44% of eligible patients) who received tPA within the 3-hour time window and 40 who did not receive thrombolytic medications despite having no documented contraindication to treatment. Factors predictive of nontreatment were older age (p=0.0005), later arrival (p=0.004), and admittance to a non-academic hospital (p=0.03). After record review, slightly fewer patients (n=61) were deemed eligible, with a tPA treatment rate of 52% among those eligible. Older age (p=0.002) and later arrival (p=0.002) continued to be predictive of nontreatment with thrombolytics after reclassification.

CONCLUSIONS

Even when more-comprehensive eligibility standards are applied, older age and later hospital arrival are associated with nontreatment with thrombolytics.

The relationship between higher blood pressure and ischaemic, haemorrhagic stroke among Chinese and Caucasians: meta-analysis

BACKGROUND AND PURPOSE

Previous studies have suggested that blood pressure is a particularly important risk factor for stroke in Chinese, and that the magnitude of the effect may be greater than in Caucasians. We performed a meta-analysis in order to define the magnitude of the risk of stroke associated with hypertension among Chinese, and to compare the magnitude of this risk with Caucasians.

METHODS

We searched Medline from 1966 to 2004, plus Chinese Medical Literature databases from 1977 to 2003 for Caucasian and Chinese studies. Results were pooled using the random effects model, and heterogeneity and publication bias were checked.

RESULTS

For a 10 mmHg increase in systolic blood pressure, the pooled risk ratio was 1.44 [95% confidence interval (CI)] 1.39-1.51 for ischaemic stroke, and 1.5 (95% CI 1.45-1.57) for haemorrhagic stroke in Chinese, versus 1.19 (95% CI 1.15-1.23) for total stroke in Caucasians. The pooled odds ratio for hypertension measured dichotomously (defined as > or =160/95 mmHg) was 5.8 (95% CI 4.7-7.2) among Chinese versus 1.93 (95% CI 1.7-2.2) among Caucasians for ischaemic stroke; and 7.2 (95% CI 5.3-9.7) in Chinese versus 3.1 (95% CI 2.5-3.9) in Caucasians for haemorrhagic stroke.

CONCLUSION

The risk of stroke associated with hypertension is consistently and significantly greater in Chinese than Caucasians. This may help genetic epidemiologists to dissect the cause of stroke, and emphasizes the particular importance of hypertension control in the Chinese population.

A561C polymorphism of E-selectin is associated with ischemic cerebrovascular disease in the Japanese population without diabetes mellitus and hypercholesterolemia

E-selectin, which is a member of the selectin superfamily of adhesion molecules, contributes to the leukocyte-endothelial cell attachments and is involved in the pathogenesis of thrombovascular diseases as a consequence. We investigated the A561C mutation in the E-selectin gene in 235 Japanese patients with ischemic cerebrovascular disease (CVD) and 301 age- and sex-matched healthy controls. Excluding the subjects with diabetes mellitus and hypercholesterolemia, the AC genotype frequencies of patients with ischemic CVD were higher than those of controls: 12.7% vs. 5.8% (P=0.04). Our results show that E-selectin gene polymorphisms represent an increased risk for ischemic CVD in the Japanese population without diabetes mellitus and hypercholesterolemia.

Association study between C-reactive protein genes and ischemic stroke in Japanese subjects

BACKGROUND

C-reactive protein (CRP) is reported to be involved in the development of atherosclerosis. Elevated CRP levels are considered to be a predictor of ischemic stroke (IS) in elderly individuals. Some single-nucleotide polymorphisms (SNP) are reportedly associated with elevated CRP levels. The aims of this study were to genotype some of the SNP in the human CRP gene and to assess the association between the CRP gene and IS.

METHODS

Japanese patients with IS (72.4 +/- 8.2 years of age, n = 152) and elderly Japanese subjects without IS (78.0 +/- 4.2 years of age, n = 304) were genotyped for four SNP of the human CRP gene: rs1341665, rs1800947, rs1130864, and rs1205. Each genotyping was performed using the TaqMan SNP genotyping assay. The haplotype-based association study was assessed with a permutation test.

RESULTS

The genotype rs1800947 was statistically significant between patients with IS and control subjects (CC+GC versus GG variant, P = .016 by multiple logistic regression analysis). This analysis revealed that the CC+GC variant of rs1800947 was an independent risk factor of IS. All four SNP were located in one haplotype block. The haplotype was constructed using rs1341665, rs1800947, and rs1130864, in that order. There was a significant association between IS and the C-C-C haplotype (P = .015).

CONCLUSIONS

The rs1800947 SNP and the C-C-C haplotype in the CRP gene appear to be prognostic markers of ischemic stroke and this polymorphism could be a useful genetic marker.

Left ventricular systolic dysfunction and the risk of ischemic stroke in a multiethnic population

BACKGROUND AND PURPOSE

Left ventricular dysfunction (LVD) is associated with cardiovascular mortality. Its association with ischemic stroke has been mainly documented after myocardial infarction. The stroke risk associated with LVD, especially of mild degree, in the general population is unclear. The purpose of this study was to evaluate the relationship between LVD and ischemic stroke in a multiethnic cohort.

METHODS

LV systolic function was assessed by transthoracic 2-dimensional echocardiography in a subset of subjects from the Northern Manhattan Study (NOMAS), 270 patients with first ischemic stroke and 288 age-, gender- and race-matched community controls. LV ejection fraction was measured by a simplified cylinder-hemiellipsoid formula, and categorized as normal (>50%), mildly (41% to 50%), moderately (31% to 40%) or severely (< or =30%) decreased. The association between impaired ejection fraction and ischemic stroke was evaluated by logistic regression analysis after adjustment for established stroke risk factors.

RESULTS

LVD of any degree was more frequent in stroke patients (24.1%) than in controls (4.9%; P<0.0001), as was moderate/severe LVD (13.3% versus 2.4%; P<0.001). A decreased ejection fraction was associated with ischemic stroke even after adjusting for other stroke risk factors. The adjusted odds ratio for any degree of LVD was 3.92 (95% CI, 1.93 to 7.97). The adjusted odds ratio for mild LVD was 3.96 (95% CI, 1.56 to 10.01) and for moderate/severe LVD 3.88 (95% CI, 1.45 to 10.39). The association between LVD of any degree and stroke was present in all age, gender and race-ethnicity subgroups.

CONCLUSIONS

LVD, even of mild degree, is independently associated with an increased risk of ischemic stroke. The assessment of LV function should be considered in the assessment of the stroke risk.

[An analysis of association between the apolipoprotein B gene EcoR1 polymorphism and ischemic stroke]

The EcoR1 polymorphism of the apolipoprotein B gene (APOB) is thought to be associated with atherothrombotic type of ischemic stroke (ATTIS) with the APOB*R1/R2 genotype as a marker of increased risk for ATTIS. We estimated odds ratio for this genotype as 2.17 in ethnic Russians and 3.39 in ethnic Tartars. The association between the EcoR1 APOB gene polymorphism and ATTIS confirmed the results of previous studies on relation of the APOB gene to vascular pathology caused by elevated lipid level and atherogenesis.

Epidemiology of stroke in young adults: race/ethnic differences

Stroke is the third leading cause of death and the leading cause of disability in the United States. Stroke incidence is clearly associated with advancing age. Although younger adults are at lower risk, stroke in this population has a particularly high public health impact because of associated indirect costs, such as longer years of lost productivity.There have been many epidemiological studies addressing race ethnic differences in overall stroke incidence and mortality, but few specifically examining these differences in the young adult population. There is evidence that race ethnic differences may have a greater effect on stroke incidence and mortality in young adults. An understanding of these differences may help better identify high risk populations and focus preventative strategies. Furthermore, analysis of race/ethnic differences in stroke subtypes may help clarify mechanisms of stroke in young adults and potential race-ethnic differences in early stroke risk factors.

The soluble epoxide hydrolase gene harbors sequence variation associated with susceptibility to and protection from incident ischemic stroke

Stroke is the leading cause of severe disability and the third leading cause of death, accounting for one of every 15 deaths in the USA. We investigated the association of polymorphisms in the soluble epoxide hydrolase gene (EPHX2) with incident ischemic stroke in African-Americans and Whites. Twelve single nucleotide polymorphisms (SNPs) spanning EPHX2 were genotyped in a case-cohort sample of 1336 participants from the Atherosclerosis Risk in Communities (ARIC) study. In each racial group, Cox proportional hazard models were constructed to assess the relationship between incident ischemic stroke and EPHX2 polymorphisms. A score test method was used to investigate the association of common haplotypes of the gene with risk of ischemic stroke. In African-Americans, two common EPHX2 haplotypes with significant and opposing relationships to ischemic stroke risk were identified. In Whites, two common haplotypes showed suggestive indication of an association with ischemic stroke risk but, as in African-Americans, these relationships were in opposite direction. These findings suggest that multiple variants exist within or near the EPHX2 gene, with greatly contrasting relationships to ischemic stroke incidence; some associated with a higher incidence and others with a lower incidence.

Emergency department evaluation of ischemic stroke and TIA: the BASIC Project

OBJECTIVE

To identify demographic and clinical variables of emergency department (ED) practices in a community-based acute stroke study.

METHODS

By both active and passive surveillance, the authors identified cerebrovascular disease cases in Nueces County, TX, as part of the Brain Attack Surveillance in Corpus Christi (BASIC) Project, a population-based stroke surveillance study, between January 1, 2000, and December 31, 2002. With use of multivariable logistic regression, variables independently associated with three separate outcomes were sought: hospital admission, brain imaging in the ED, and neurologist consultation in the ED. Prespecified variables included age, sex, ethnicity, insurance status, NIH Stroke Scale score, type of stroke (ischemic stroke or TIA), vascular risk factors, and symptom presentation variables. Percentage use of recombinant tissue plasminogen activator (rt-PA) was calculated.

RESULTS

A total of 941 Mexican Americans (MAs) and 855 non-Hispanic whites (NHWs) were seen for ischemic stroke (66%) or TIA (34%). Only 8% of patients received an in-person neurology consultation in the ED, and 12% did not receive any head imaging. TIA was negatively associated with neurology consultations compared with completed stroke (odds ratio [OR] 0.35 [95% CI 0.21 to 0.57]). TIA (OR 0.14 [0.10 to 0.19]) and sensory symptoms (OR 0.59 [0.44 to 0.81]) were also negatively associated with hospital admission. MAs (OR 0.58 [0.35 to 0.98]) were less likely to have neurology consultations in the ED than NHWs. Only 1.7% of patients were treated with rt-PA.

CONCLUSIONS

Neurologists are seldom involved with acute cerebrovascular care in the emergency department (ED), especially in patients with TIA. Greater neurologist involvement may improve acute stroke diagnosis and treatment efforts in the ED.

Promoter polymorphisms in the nitric oxide synthase 3 gene are associated with ischemic stroke susceptibility in young black women

BACKGROUND AND PURPOSE

Endothelial nitric oxide exerts a variety of protective effects on endothelial cells and blood vessels, and therefore the nitric oxide synthase 3 gene (NOS3) is a logical candidate gene for stroke susceptibility.

METHODS

We used the population-based Stroke Prevention in Young Women case-control study to assess the association of five NOS3 polymorphisms in 110 cases (46% black) with ischemic stroke and 206 controls (38% black), 15 to 44 years of age. Polymorphisms included 3 single nucleotide polymorphisms (SNPs) in the promoter region (-1468 T>A, -922 G>A, -786 T>C), 1 SNP in exon 7 (G894T), and 1 insertion/deletion polymorphism within intron 4.

RESULTS

Significant associations with both the -922 G>A and -786 T>C SNPs with ischemic stroke were observed in the black, but not the white, population. This association was attributable to an increased prevalence of the -922 A allele (OR=3.0, 95% CI=1.3 to 6.8; P=0.005) and the -786 T allele (OR=2.9, 95% CI=1.3 to 6.4; P=0.005) in cases versus controls. These 2 SNPs were in strong linkage disequilibrium (D'=1.0), making it impossible to determine, within the confines of this genetic study, whether 1 or both of these polymorphisms are functionally related to NOS3 expression. Two sets of haplotypes were also identified, 1 of which may confer an increased susceptibility to stroke in blacks, whereas the other appears to be protective.

CONCLUSIONS

Promoter variants in NOS3 may be associated with ischemic stroke susceptibility among young black women.

Stroke burden in Mexican Americans: the impact of mortality following stroke

PURPOSE

To estimate ethnic-specific all-cause mortality risk following ischemic stroke and to compare mortality risk by ethnicity.

METHODS

DATA from the Brain Attack Surveillance in Corpus Christi Project, a population-based stroke surveillance study, were used. Stroke cases between January 1, 2000 and December 31, 2002 were identified from emergency department (ED) and hospital sources (n = 1,234). Deaths for the same period were identified from the surveillance of stroke cases, the Texas Department of Health, the coroner, and the Social Security Death Index. Ethnic-specific all-cause cumulative mortality risk was estimated at 28 days and 36 months using Kaplan Meier analysis. Cox proportional hazards regression was used to compare mortality risk by ethnicity.

RESULTS

Cumulative 28-day all-cause mortality risk for Mexican Americans (MAs) was 7.8% and for non-Hispanic whites (NHWs) was 13.5%. Cumulative 36-month all-cause mortality risk was 31.3% in MAs and 47.2% in NHWs. MAs had lower 28-day (RR = 0.58; 95% CI: 0.41, 0.84) and 36-month all-cause mortality risk (RR = 0.79, 95% CI: 0.64, 0.98) compared with NHWs, adjusted for confounders.

CONCLUSIONS

Better survival after stroke in MAs is surprising considering their similar stroke subtype and severity compared with NHWs. Social or psychological factors, which may explain this difference, should be explored.

[Intercellular adhesion molecule-1 gene K469E polymorphism and genetic susceptibility of ischemic stroke in Chinese Zhuang populations]

OBJECTIVE

To examine the relationship between intercellular adhesion molecule-1 (ICAM-1) gene polymorphism and ischemic stroke (IS) in Chinese Zhuang populations.

METHODS

The K469E polymorphism in the exon 6 of ICAM-1 gene was detected by polymerase chain reaction-restriction fragment length polymorphism analysis and DNA sequencing in 205 patients with IS of Zhuang nationality and in 210 healthy controls, and the serum level of ICAM-1 was determined by enzyme-linked immunosorbent assay.

RESULTS

The IS group showed significantly higher serum levels of ICAM-1 than did the control group (P < 0.01). There was significant difference in frequencies of allele and genotype in K469E polymorphism between IS and control groups, respectively (P < 0.05). The K allele carriers had 1.424 times the risk of suffering from IS as compared with the E allele carriers (OR = 1.424, 95% CI: 1.071 - 1.894); the serum ICAM-1 level of E allele carriers was significantly higher than that of K allele carriers (501.24 +/- 139.56 ng/ml vs 475.17 +/- 118.35 ng/ml, P < 0.01).

CONCLUSION

There is an association between ICAM-1 gene K469E polymorphism and IS, and E allele may be a genetic risk factor of IS among Guangxi Zhuangs, in which the ICAM-1 E allele carriers may have up-regulated expression of ICAM-1 and hence are at a higher risk of ischemic stroke.

Ischemic stroke subtype incidence among whites, blacks, and Hispanics: the Northern Manhattan Study

BACKGROUND

Stroke incidence is greater in blacks than in whites; data on Hispanics are limited. Comparing subtype-specific ischemic stroke incidence rates may help to explain race-ethnic differences in stroke risk. The aim of this population-based study was to determine ischemic stroke subtype incidence rates for whites, blacks, and Hispanics living in one community.

METHODS AND RESULTS

A comprehensive stroke surveillance system incorporating multiple overlapping strategies was used to identify all cases of first ischemic stroke occurring between July 1, 1993, and June 30, 1997, in northern Manhattan. Ischemic stroke subtypes were determined according to a modified NINDS scheme, and age-adjusted, race-specific incidence rates calculated. The annual age-adjusted incidence of first ischemic stroke per 100,000 was 88 (95% CI, 75 to 101) in whites, 149 (95% CI, 132 to 165) in Hispanics, and 191 (95% CI, 160 to 221) in blacks. Among blacks compared with whites, the relative rate of intracranial atherosclerotic stroke was 5.85 (95% CI, 1.82 to 18.73); extracranial atherosclerotic stroke, 3.18 (95% CI, 1.42 to 7.13); lacunar stroke, 3.09 (95% CI, 1.86 to 5.11); and cardioembolic stroke, 1.58 (95% CI, 0.99 to 2.52). Among Hispanics compared with whites, the relative rate of intracranial atherosclerotic stroke was 5.00 (95% CI, 1.69 to 14.76); extracranial atherosclerotic stroke, 1.71 (95% CI, 0.80 to 3.63); lacunar stroke, 2.32 (95% CI, 1.48 to 3.63); and cardioembolic stroke, 1.42 (95% CI, 0.97 to 2.09).

CONCLUSIONS

The high ischemic stroke incidence among blacks and Hispanics compared with whites is due to higher rates of all ischemic stroke subtypes.

Ischemic stroke subtypes among Mexican Americans and non-Hispanic whites: the BASIC Project

Ischemic stroke subtype distribution was compared between Mexican Americans (MAs) and non-Hispanic whites (NHWs) in a community-based stroke surveillance study in Nueces County, TX. There was no difference in the distribution of stroke subtype by ethnicity (p = 0.19). There was a similar proportion of small-vessel and large-artery strokes between the two ethnic groups (p = 0.32). Differences in stroke rates among MAs and NHWs are not explained by the distribution of ischemic stroke subtypes.

Ethnic Differences in Risk Factors for Ischemic Stroke

Background and Purpose— The aim is to estimate the relative risk and population attributable risk (PAR) of risk factors for ischemic stroke by ethnic group.

Methods— In this case–control study, cases of first ischemic stroke were taken from the South London Stroke Register and controls from a cross-sectional prevalence survey covering the same area. PAR was determined for each risk factor by ethnic group. Multivariable analysis was used to examine the association between risk factors and ischemic stroke across all ethnic groups.

Results— 664 cases and 716 controls aged 45 to 74 years were included, with ethnicity of white 78%:42%, black Caribbean 16%:43%, and black African 6%:15%, respectively. For the white group, high PAR was found for ischemic heart disease (IHD) on ECG (56% [95% CI, 49% to 62%]), obesity (49% [95% CI, 40% to 56%]), hypertension (HT) (38% [95% CI, 29% to 46%]), smoking (31% [95% CI, 19% to 41%]), transient ischemic attack (TIA) (23% [95% CI, 19% to 27%]), and atrial fibrillation (AF) (16% [95% CI, 10% to 21%]). In the black Caribbean compared with the white group, PAR was higher for HT (46% [95% CI, 21% to 63%]) and diabetes mellitus (DM) (29% [95% CI, 14% to 42%]), and lower for current smoking (18% [95% CI, 1% to 32%]) and AF (10% [95% CI, 0% to 18%]). In the black African group HT had a higher PAR (59% [95% CI, 91% to 82%]) than the other groups. PAR for AF (11% [95% CI, −11% to 29%]), obesity (30% [95% CI, −20% to 60%]), and DM (4% [95% CI, −25% to 26%]) was low compared with the other groups. In multivariable analysis, risk factors associated with ischemic stroke included TIA, AF, IHD on ECG, smoking, excess alcohol, obesity, HT, and DM.

Conclusion— In the first European case-control study examining risk factors for ischemic stroke in black Caribbean and African populations, some differences were demonstrated in the impact of risk factors between these groups. It may be important to address such differences when developing stroke preventative strategies.

Racial disparities in the pathogenesis and outcomes for patients with ischemic stroke

Using the 2000 National Inpatient Sample, this study examined the patterns of disparities regarding acute care outcomes of ischemic stroke among Caucasian, African-American, Hispanic, and Asian/Pacific-Islander patients. The data from 13,316 patients with carotid artery-related stroke and 33,149 patients with cerebral artery occlusion were examined. Although racial disparities associated with carotid artery occlusion and cerebral artery occlusion varied, overall, as compared with Caucasians, minorities suffered greater neurologic impairment and had poorer outcomes. For example, among patients with carotid artery occlusion, 62.5% of Caucasian patients had paralysis, compared with 71.2% of African Americans, 69.1% of Hispanics, and 74.0% of Asian patients. Poorer outcomes among African Americans and Hispanics coexisted with higher frequencies of cerebral artery disease in these populations, suggesting possible etiologic factors related to diabetes and high cholesterol levels. Etiologic factors contributing to disparities in the Asian population remain to be determined.

[Study of C1423T polymorphism of the von Willebrand factor-cleaving protease gene in Chinese Han population]

OBJECTIVE

The C1423T polymorphism in von Willebrand factor-cleaving protease (vWF-cp) gene affects its enzyme activity. The present study was to investigate the polymorphism frequency among Chinese Han population and its relevance to arterial thrombotic disorders.

METHODS

An amplified 366 bp fragment of human vWF-cp gene was analyzed by Rsa I restriction assay in 400 unrelated individuals including 150 with acute ischemic stroke (AIS), 103 with acute myocardial infarction (AMI) and 147 age- and gender-matched healthy controls. The resulting products were analyzed by 12% polyacrylamide gels electrophoresis and stained with ethidium bromide.

RESULTS

Twelve cases were C1423T heterozygous, the C1423T frequencies were 98.5% and 1.5%, and the heterozygosity and allele frequency were 3% and 1.5%, respectively, which were remarkably lower than those reported in Japanese population. No 1423T/T homozygote was found. Besides, there was no significant difference between healthy controls and patients with thrombotic disorders.

CONCLUSION

C1423T polymorphism is low frequency in both controls and patients of Han population.

Left ventricular mass and geometry and the risk of ischemic stroke

BACKGROUND AND PURPOSE

Left ventricular hypertrophy (LVH) is a risk factor for cardiovascular events, but its effect on ischemic stroke risk is established mainly in whites. The effect of LV geometry on stroke risk has not been defined. The aim of the present study was to evaluate whether LVH and LV geometry are independently associated with increased ischemic stroke risk in a multiethnic population.

METHODS

A population-based case-control study was conducted on 394 patients with first ischemic stroke and 413 age-, sex-, and race-ethnicity-matched community control subjects. LV mass was measured by transthoracic echocardiography. LV geometric patterns (normal, concentric remodeling, concentric or eccentric hypertrophy) were identified. Stroke risk associated with LVH and different LV geometric patterns was assessed by conditional logistic regression analysis in the overall group and age, sex, and race-ethnic strata, with adjustment for established stroke risk factors.

RESULTS

Concentric hypertrophy carried the greatest stroke risk (adjusted odds ratio [OR], 3.5; 95% confidence interval [CI], 2.0 to 6.2), followed by eccentric hypertrophy (adjusted OR, 2.4; 95% CI, 2.0 to 4.3). Concentric remodeling carried slightly increased stroke risk (adjusted OR, 1.7; 95% CI, 1.0 to 2.9). Increased LV relative wall thickness was independently associated with stroke after adjustment for LV mass (OR, 1.6; 95% CI, 1.1 to 2.3).

CONCLUSIONS

LVH and abnormal LV geometry are independently associated with increased stroke risk. LVH is strongly associated with ischemic stroke in all age, sex, and race-ethnic subgroups. Increased LV relative wall thickness imparts an increased stroke risk after adjustment for LV mass and is of additional value in stroke risk prediction.

Risk Factors for Incident Stroke among Patients with End-Stage Renal Disease

ABSTRACT. Although patients with ESRD experience markedly higher rates of stroke, no studies in the US have identified risk factors associated with stroke in this population. It was hypothesized that black race, malnutrition, and elevated BP would be associated with the risk of stroke among patients with ESRD. Data from the United States Renal Data Systems were used. Adult Medicare-insured hemodialysis and peritoneal dialysis patients without a history of stroke or transient ischemic attack (TIA) were considered for analysis. The primary outcome was hospitalized or fatal stroke. Cox proportional hazards models were used to determine the associations between the primary predictor variables and stroke. The rate of incident stroke was 33/1,000 person-years in the study sample. After adjustment for age and other patient characteristics, three markers of malnutrition were associated with the risk of stroke—serum albumin (per 1 g/dl decrease, hazard ratio [HR] = 1.43), height-adjusted body weight (per 25% decrease, HR = 1.09), and a subjective assessment of undernourishment (HR = 1.27)—as was higher mean BP (per 10 mmHg, HR = 1.11). The association between black race varied by cardiac disease status, with blacks estimated to be at lower risk than whites among individuals with cardiac disease (HR = 0.74), but at higher risk among individuals without cardiac disease (HR = 1.24). This study confirms the extraordinarily high rates of stroke in ESRD patients on dialysis and identifies high mean BP and malnutrition as potentially modifiable risk factors. The association between black race and stroke differs by cardiac disease status; the reasons for this differing effect of race deserve further investigation. E-mail: seliger@u.washington.edu

Race-ethnic differences in patent foramen ovale, atrial septal aneurysm, and right atrial anatomy among ischemic stroke patients

BACKGROUND AND PURPOSE

Stroke remains a substantial cause of mortality and morbidity in the United States. Racial differences in stroke incidence and mortality persist with well-known excesses among blacks. Information on stroke among Hispanics is limited. In particular, little is known about whether patent foramen ovale (PFO), atrial septal aneurysm (ASA), and other atrial anomalies associated with cryptogenic stroke differ among minority populations.

METHODS

As a part of the PFO in Cryptogenic Stroke Study, transesophageal echocardiography was performed in a cohort of 630 ischemic stroke patients (mean age, 59+/-12 years; 44% women; 45% whites, 35% blacks, 17% Hispanics, 3% other). The prevalences of PFO, ASA, and right atrial (RA) anatomy favoring paradoxical embolization were compared among race-ethnic groups. Statistical analyses used analysis of variance for continuous variables and logistic regression for dichotomous variables with adjustments for age and sex.

RESULTS

Age- and sex-adjusted prevalences of PFO and ASA were similar across race-ethnic subgroups. However, large PFO was significantly less prevalent among blacks than among whites (odds ratio, 0.47; 95% confidence interval, 0.24 to 0.91; P=0.02). RA anatomy favoring paradoxical embolization was also significantly less prevalent among blacks compared with whites (odds ratio, 0.62; 95% confidence interval, 0.43 to 0.91; P=0.01). There were no significant differences in prevalence between whites and Hispanics.

CONCLUSIONS

Although the frequency of PFO did not vary among race-ethnic groups, a large PFO and RA anatomy favoring paradoxical embolization were significantly more prevalent among whites and Hispanics compared with blacks. These may be relatively more important risk factors for stroke among whites and Hispanics than among blacks.

Veterans Administration Acute Stroke (VASt) Study: lack of race/ethnic-based differences in utilization of stroke-related procedures or services

BACKGROUND AND PURPOSE

Race/ethnic-based disparities in the utilization of health-related services have been reported. Data collected as part of the Veterans Administration Acute Stroke Study (VASt) were analyzed to determine whether similar differences were present in patients admitted to Veterans Administration (VA) hospitals with acute ischemic stroke.

METHODS

VASt prospectively identified stroke patients admitted to 9 geographically separated VA hospitals between April 1995 and March 1997. Demographic characteristics and all inpatient diagnostic tests/procedures were recorded. Frequencies were compared with chi2 tests.

RESULTS

Of 1073 enrolled patients, 775 (white, n=520; nonwhite, n=255, including 226 blacks and 28 Hispanic-Americans) with ischemic stroke were admitted from home. Mean ages (71.0+/-0.6 versus 71.9+/-0.4 years; P=0.25) and Trial of ORG 10172 in Acute Stroke Treatment (TOAST) stroke types (atherothrombotic, 12.9% versus 13.3%; cardioembolic, 16.5% versus 18.0%; lacunar, 26.4% versus 27.1%; other, 1.4% versus 2.0%; unclassified, 42.9% versus 39.6%; P=0.89) for whites versus nonwhites were similar. There were no race/ethnic-based differences in the utilization of brain CT (91.0% versus 92.2%; P=0.58), MRI (36.2% versus 41.6%; P=0.14), transthoracic (52.5% versus 53.7%; P=0.75) or transesophageal echocardiography (10.2% versus 10.6%; P=0.86), 24-hour ECG (3.3% versus 1.6%; P=0.17), carotid ultrasound (64.0% versus 62.0%; P=0.57), carotid endarterectomy (1.5% versus 0.8%; P=0.38), rehabilitation evaluations (71.0% versus 76.5%; P=0.11), speech therapy (9.6% versus 12.6%; P=0.21), recreational therapy (3.1% versus 2.0%; P=0.37), or occupational therapy (16.0% versus 19.6%; P=0.20) for whites versus nonwhites, respectively. Angiography was performed less frequently (3.1% versus 8.5%; P=0.01) and ECG more frequently (81.6% versus 73.5%; P=0.01) in nonwhites. The proportions of patients discharged functionally independent were also similar (52% of whites and 50% of nonwhites had discharge Rankin Scale scores of 0, 1, or 2; P=0.63).

CONCLUSIONS

Aside from cerebral angiography and ECG, there were no race/ethnic-based disparities in the utilization of a variety of stroke-related procedures and services. The difference in the use of angiography is unlikely to be related to a difference in screening for carotid endarterectomy because there was no difference in the frequency of carotid ultrasonography. The reason ECG was obtained more frequently in nonwhites is uncertain.

Spouses and unrelated friends of probands as controls for stroke genetics studies

To plan a multisite, ischemic stroke genetic study, stroke patients were surveyed about the availability and characteristics of a convenience sample of spouse/friend controls. 65% of all stroke-affected probands reported a living spouse. A more detailed survey was conducted at the University of Virginia, Charlottesville, Va., USA: 51% of stroke patients reported a living, stroke-free spouse who would be willing to serve as a control, and 49% reported having a stroke-free friend who would be willing to serve as a control. Overall, 75% of stroke patients reported at least 1 individual willing to participate as a control. Cases without an identified control were more likely to be non-white (48%) than were cases with a control (13%; p = 0.00004). Cases were older than controls (67.3 vs. 59.2 years; p = 0.000002), and a greater proportion of cases than controls were male (57 vs. 33%; p = 0.0002). Without proper attention to matching, the use of a spouse/friend convenience sample would result in imbalances in basic demographic characteristics.

Sex differences in US mortality rates for stroke and stroke subtypes by race/ethnicity and age, 1995-1998

BACKGROUND AND PURPOSE

Ischemic stroke accounts for 70% to 80% of all strokes, but intracerebral and subarachnoid hemorrhagic strokes have greater fatality. Age-standardized death rates from overall stroke are higher among men than women, but little is known about sex differences in stroke subtype mortality by race/ethnicity.

METHODS

We analyzed 1995 to 1998 national death certificate data to compare sex-specific age-standardized death rates (per 100 000) for ischemic stroke (n=507 256), intracerebral hemorrhagic stroke (n=98 709), and subarachnoid hemorrhagic stroke (n=27 334) among whites, blacks, American Indians/Alaska Natives, Asians/Pacific Islanders, and Hispanics. We calculated rate ratios and 95% CIs comparing women with men within age and racial/ethnic groups.

RESULTS

Age-specific rates of ischemic and intracerebral hemorrhagic stroke deaths were lower for women than for men aged 25 to 44 and 45 to 64 years but were higher for ischemic stroke among older women, aged > or =65 years. Only among whites did women have higher age-standardized rates of ischemic stroke. Age-standardized death rates for intracerebral hemorrhagic stroke among women were lower than or similar to those among men in all racial/ethnic groups. Women had higher risk of death from subarachnoid hemorrhagic; this sex differential increased with age.

CONCLUSIONS

The female-to-male mortality ratio differs for stroke subtypes by race/ethnicity and age. A primary public health effort should focus on increasing the awareness of stroke symptoms, particularly among people at high risk, to decrease delay in early detection and effective stroke treatment.

Utilization of intravenous tissue-type plasminogen activator for ischemic stroke at academic medical centers: the influence of ethnicity

BACKGROUND AND PURPOSE

We sought to measure the overall rate of usage of tissue-type plasminogen activator (tPA) for ischemic stroke at academic medical centers, and to determine whether ethnicity was associated with usage.

METHODS

Between June and December 1999, 42 academic medical centers in the United States each identified 30 consecutive ischemic stroke cases. Medical records were reviewed and information on demographics, medical history, and treatment were abstracted. Rates of tPA use were compared for African Americans and whites in univariate analysis and after adjustment for age, gender, stroke severity, and type of medical insurance with multivariable logistic regression.

RESULTS

Complete information was available for 1195 ischemic stroke patients; 788 were whites and 285 were African Americans: Overall, 49 patients (4.1%) received tPA. In the subgroup of 189 patients without a documented contraindication to therapy, 39 (20.6%) received tPA. Ten (20%) of those receiving tPA had documented contraindication. African Americans were one fifth as likely to receive tPA as whites (1.1% African Americans versus 5.3%; P=0.001), and the difference persisted after adjustment (OR 0.21, 95% CI 0.06 to 0.68; P=0.01). When comparison was restricted to those without a documented contraindication to tPA, the difference remained significant (OR 0.24, 95% CI 0.06 to 0.93; P=0.04). Medical insurance type was independently associated with tPA treatment. After adjustment for ethnicity and other demographic characteristics, those with Medicaid or no insurance were one ninth as likely to receive tPA as those with private medical insurance (OR 0.11, 95% CI 0.02 to 0.17; P=0.003).

CONCLUSIONS

tPA is used infrequently for ischemic stroke at US academic medical centers, even among qualifying candidates. African Americans are significantly less likely to receive tPA for ischemic stroke. Contraindications to treatment do not appear to account for the difference.

Factors preventing African Americans from seeking early intervention in the treatment of ischemic strokes

The most widely advocated drug that has been developed to decrease and possibly reverse the crippling effect of stroke is recombinant tissue plasminogen activator (rt-PA). In the treatment of ischemic stroke, rt-PA must be administered within the first 3 hr after the onset of symptoms for optimal efficacy and avoidance of life-threatening cerebral hemorrhage. This study sought to determine whether African-American stroke victims presented for treatment within the first 3 hr. In the study, we identified some of the more common reasons for the lack of prompt presentation. A prospective survey of 103 randomly selected acute stroke patients was performed. We found that less than half of this population sought assistance in the emergency department in time to take advantage of rt-PA therapy. When confronted with symptoms that were consistent with acute stroke, many patients either chose to ignore them or thought that they were experiencing transient phenomena. Three factors were identified as possible reasons for the lack of prompt response: (a) a lack of information about available treatment options; (b) the inability to recognize the early warning signs of an impending stroke; and (c) denial of illness. This study may help to evolve strategies that must be instituted to better educate the community about the early recognition of stroke and available treatment alternatives.

Chlamydia pneumoniae and the risk of first ischemic stroke : The Northern Manhattan Stroke Study

BACKGROUND AND PURPOSE

Serological evidence of infection with Chlamydia pneumoniae has been associated with cardiovascular disease in multiple epidemiological studies. The data on its association with ischemic stroke are limited. We sought to determine whether chronic C pneumoniae infection is associated with ischemic stroke in a multi-ethnic population.

METHODS

The Northern Manhattan Stroke Study contains a population-based, case-control study component. Cases had first ischemic stroke and matched control subjects were derived through random digit dialing. Titers of IgG, IgA, and IgM antibodies specific for C pneumoniae were measured with the use of microimmunofluorescence, and titers >/=1:16 were considered positive. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjustment for medical, behavioral, and socioeconomic factors.

RESULTS

Eighty-nine cases and 89 control subjects were selected. Mean age among cases was 68.5+/-12.8 years; 53% were women and 15% of the subjects were white, 28% were black, and 54% were Hispanic. Elevated C pneumoniae IgA titers were significantly associated with risk of ischemic stroke after adjusting for other stroke risk factors (adjusted OR 4. 51, 95% CI 1.44 to 14.06). IgG titers were less strongly associated with stroke risk (adjusted OR 2.59, 95% CI 0.87 to 7.75). The association of IgA with stroke risk was detected in both younger and older groups, in men and women, and in whites, blacks, and Hispanics. There was also a significant continuous increase in risk associated with the log-transformation of the titer for IgA (adjusted OR 1.32, 95% CI 1.05 to 1.66) but not IgG.

CONCLUSIONS

Serological evidence of chronic infection with C pneumoniae is associated with risk of ischemic stroke in an urban, multi-ethnic population. IgA titers may be a better marker of this risk than are IgG titers. This association is independent of other vascular disease risk factors. Further prospective epidemiological studies of the effect of this infection on stroke risk are warranted.

Elevated anticardiolipin antibody titer is a stroke risk factor in a multiethnic population independent of isotype or degree of positivity

BACKGROUND AND PURPOSE

Previous studies have produced conflicting results regarding the putative association between anticardiolipin antibodies (aCL) and infarction in the general stroke population. These inconsistencies may be a function of sample size and methodological differences among the studies. The purpose of the present study, the largest case-control study of this issue to date, was to assess aCL status as an independent risk factor for ischemic stroke in a multiethnic, urban population.

METHODS

We obtained aCL titers in 524 hospitalized acute stroke patients and 1020 community controls enrolled in the Minorities Risk Factors and Stroke Study. The results were interpreted as negative (</=22.9 IgG phospholipid [GPL] or 10.9 IgM phospholipid [MPL] units), low positive (22.9 to 30.0 GPL or 10.9 to 15.0 MPL units), or high positive (>30.0 GPL or 15.0 MPL units). Odds ratios (ORs) were adjusted for age, sex, race/ethnicity, history of diabetes, hypertension, atrial fibrillation, coronary artery disease, and current cigarette smoking.

RESULTS

A positive aCL titer was present in 11% (111/1020) of controls and 34% (180/524) of cases. The adjusted OR for any positive aCL titer was 4.0 (95% CI, 3.0 to 5.5). For any positive IgG aCL titer this value was 3.9 (95% CI, 2.8 to 5.5), and for any positive IgM aCL titer it was 3.4 (95% CI, 2.1 to 5.5). There were no significant differences in ORs associated with high- or low-positive IgG or IgM aCL titers.

CONCLUSIONS

In the largest study of its kind to date, aCL antibodies were demonstrated to be independent stroke risk factors across the 3 ethnic groups studied, conferring a 4-fold increased risk of ischemic stroke. IgG and for the first time IgM aCL were each shown to be associated with increased stroke risk. The prevalence of these antibodies and the stroke risk associated appear greater than previously reported.

Analysis of Canadian population with potential geographic access to intravenous thrombolysis for acute ischemic stroke

BACKGROUND AND PURPOSE

We sought to identify the Canadian population with potential access to intravenous tissue plasminogen activator within 3 hours of onset of acute ischemic stroke.

METHODS

Assuming that 60 minutes is needed for stroke recognition, emergency room evaluation, and administration of tissue plasminogen activator, 120 minutes remain for transport, using a 3-hour treatment window. Ambulance databases were analyzed for transport times of 60, 90, and 120 minutes and were found to correspond to transport distances of 32, 64, and 105 kilometers (20, 40, and 65 miles), respectively. Using Geographical Information System (GIS) software, these radii were overlaid on thematic maps of Canadian hospitals identified as having a third- or fourth-generation CT and with a neurologist and an emergency physician on staff. Analysis was then performed on complete Canadian census data from 1991 and the interim 1996 census count.

RESULTS

67.3%, 78.2%, and 85.3% of the total Canadian population were within 32, 64, and 105 kilometers, respectively, of an identified hospital. For individuals >/=65 years of age, 64.4%, 77.0%, and 85.7% were within the respective radii. Complete analysis by age, ethnic origin, and gender are detailed.

CONCLUSIONS

In the model described, a substantial percentage of the Canadian population has geographic access to a hospital potentially capable of delivering intravenous thrombolysis for acute ischemic stroke. GIS analysis can identify both population groups and rural areas with limited access to thrombolytic stroke treatment. A coordinated emergency medical service response for stroke is advocated to maximize coverage, as a 60-minute delay in emergency room arrival eliminated 5.1 million people from potential treatment.

Risk profile and prediction of long-term ischemic stroke mortality: a 21-year follow-up in the Israeli Ischemic Heart Disease (IIHD) Project

BACKGROUND

Multinational comparisons demonstrate marked ethnic and regional variation in stroke mortality and risk-factor distribution. We assessed the role of ethnicity and estimated the cumulative effect of multiple risk factors on long-term ischemic stroke mortality.

METHODS AND RESULTS

Civil servants and municipal employees in Israel (n=9734 men; age, >/=42 years), chosen by stratified sampling in 6 prespecified areas of birth (those born in Israel and those who were immigrants from 5 other regional-ethnic strata), were included in the Israeli Ischemic Heart Disease (IIHD) Project. Over a 21-year follow-up period, age-adjusted mortality rates per 10 000 person-years attributed to ischemic stroke (n=282; International Classification of Diseases [ICD]-9 codes 433 to 438) were higher among immigrants to Israel from northern Africa and the Mideast (17.1 to 19.0), than from 3 parts of Europe (11.3 to 12.4). Crude rates per 1000 subjects observed in those born in Asia or Africa (29.4 to 31.2) exceeded rates predicted by risk-factor profiles (21.4 to 24.9). Adjusted hazard ratios were 3.00 for age (per 10 years), 2.15 for left ventricular hypertrophy, 1.69 for systolic blood pressure (BP, per 20 mm Hg), 1.86 for diabetes mellitus, 1.83 for peripheral vascular disease, 1.79 for smoking (>20 cigarettes per day), 1.51 for coronary heart disease, 1.16 for percent cholesterol contained in the HDL fraction (%HDL, per 5% decrease), and 1.88 for diastolic BP (per 12 mm Hg; assessed in an alternative model). Accounting for regression dilution bias and assessed from repeat measurements, we found that hazard ratio estimates associated with diastolic BP, systolic BP, and percent HDL (per increments described) increased to 3.22, 2.23, and 1.23, respectively. Ischemic stroke mortality rates were 30-fold greater among subjects at the highest versus the lowest quintile of predicted probability according to risk-factor profiles (81.2 versus 2.6 per 1000 subjects).

CONCLUSIONS

Assessment of multiple risk factors provides useful quantitative prediction of long-term ischemic stroke mortality risk. Regional-ethnic variations are consistent with a hypothesis that other, undetermined inherent genetic or sociocultural factors act to increase ischemic stroke mortality rates in immigrants to Israel from the Mideast and northern Africa over that predicted by conventional risk factors.

Survey of the causes of stroke among Mexican Americans in South Texas

Management strategies for optimal stroke prevention depend on the cause of threatened stroke. We know relatively little about the etiology of stroke in Mexican Americans, who make up one quarter of the population in Texas. A retrospective case series of 159 consecutive patients hospitalized in San Antonio, Tex, for acute, first-ever stroke compared risk factors, features, and causes of stroke between Mexican Americans and whites. Mexican Americans who had strokes were significantly younger than whites and had diabetes mellitus more often. Intracerebral hemorrhage and lacunar infarcts occurred often in Mexican Americans. Ethnicity appeared to be an independent risk factor for lacunar infarction. Mortality and functional outcome at the time of hospital discharge were similar in Mexican Americans and whites. Intrinsic small-vessel disease causing lacunar infarcts and intracerebral hemorrhage accounts for about one half of strokes in Mexican Americans. Stroke among Mexican Americans in South Texas has a distinctive profile with implications for its prevention.