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

Surgical and percutaneous management of carotid artery stenosis

Stroke is one of the leading causes of morbidity and mortality in the United States. Approximately 700,000 Americans suffer from a stroke per year and 270,000 of these patients will die as a result of their stroke. The etiology of cerebrovascular events can be attributed to carotid artery disease in 20-30% of cases. Carotid endarterectomy has been shown to be beneficial in selected patients with symptomatic and asymptomatic carotid artery stenosis. Percutaneous treatment of carotid disease appears to be effective when performed with distal protection by an experienced operator. This review presents the clinical trial data regarding surgical and percutaneous management of carotid disease.

Association of the complement factor H Y402H polymorphism with cardiovascular disease is dependent upon hypertension status: The ARIC study

BACKGROUND

Complement factor H (CFH) is a plasma protein that is essential in the regulation of the alternative complement pathway and has been implicated as taking part in complement inhibition in atherogenesis. We evaluated the association of the Y402H polymorphism with incident coronary heart disease (CHD), incident ischemic stroke, and carotid artery wall thickness (intima-media thickness (IMT)) in the Atherosclerosis Risk in Communities (ARIC) cohort.

METHODS

Incident ischemic stroke and CHD were identified through annual telephone calls and hospital and death certificate surveillance. Carotid IMT was measured by means of high-resolution B-mode ultrasound. Four hundred eighty-three validated ischemic stroke and 1,544 CHD events were identified. Because of allele frequency differences between whites and African Americans, analyses were performed separately according to the racial group.

RESULTS

The 402HH homozygous genotype was a significant predictor of incident ischemic stroke in whites (hazard rate ratio (HRR) 1.47, 95% confidence interval (CI) 1.05-2.05). Significant interaction effects between genotype and hypertension were observed for CHD in whites and for cIMT in whites and African Americans. In further analyses of incident CHD, genotypes carrying the 402H allele were a significant predictor of incident CHD in whites who had hypertension (402YH: HRR 1.19, 95% CI 1.01-1.40; 402HH: HRR 1.28, 95% CI 1.04-1.57). The 402H allele was also associated with higher cIMT measures for whites in the overall cohort, and for whites with hypertension.

CONCLUSION

The CFH 402H allele was associated with an increased risk for incident CHD and ischemic stroke in whites, with the strength and significance of the association dependent upon hypertension status.

Warfarin therapy: in need of improvement after all these years

BACKGROUND

Warfarin therapy has been used clinically for over 60 years, yet continues to be problematic because of its narrow therapeutic index and large inter-individual variability in patient response. As a result, warfarin is a leading cause of serious medication-related adverse events, and its efficacy is also suboptimal.

OBJECTIVE

To review factors that are responsible for variable response to warfarin, including clinical, environmental, and genetic factors, and to explore some possible approaches to improving warfarin therapy.

RESULTS

Recent efforts have focused on developing dosing algorithms that included genetic information to try to improve warfarin dosing. These dosing algorithms hold promise, but have not been fully validated or tested in rigorous clinical trials. Perhaps equally importantly, adherence to warfarin is a major problem that should be addressed with innovative and cost-effective interventions.

CONCLUSION

Additional research is needed to further test whether interventions can be used to improve warfarin dosing and outcomes.

APOE/C1/C4/C2 hepatic control region polymorphism influences plasma apoE and LDL cholesterol levels

We characterized 102 kb of chromosome 19 containing the apolipoprotein (APO) E/C1/C4/C2 cluster and two flanking genes for common DNA variants associated with plasma low-density lipoprotein cholesterol (LDL-C) level. DNA variants were identified by comparing sequences of 48 haploid hybrid cell lines. We genotyped participants (1943 Whites and 2046 African-Americans) of the Coronary Artery Risk Development in Young Adults study for 115 variants. After controlling for the effects of the APOE epsilon2/3/4 polymorphism, a single nucleotide polymorphism, rs35136575, in the downstream hepatic control region 2 (HCR-2) was associated with LDL-C in Caucasians (P = 0.0004), accounting for 1% of variation. We genotyped rs35136575 in the Atherosclerosis Risk in Communities (ARIC) cohort (3679 African-Americans and 10 427 Whites) and in the Genetic Epidemiology Network of Arteriopathy (GENOA) sibships (1381 African-Americans in 592 sibships, 1116 Caucasians in 503 sibships and 1378 Mexican-Americans in 416 sibships), finding association with LDL-C level in ARIC Caucasians (P = 0.0064). Lower plasma LDL-C was observed with the rare allele. Plasma apoE level was strongly associated with HCR-2 variant genotype in all three GENOA samples (P </= 0.002), indicating an effect on apoE concentration. Patterns of association for plasma apo A-I, apoB, LDL-C, high-density lipoprotein cholesterol, total cholesterol and triglyceride levels with rs35136575 in the population-based samples evaluated in this study suggest a pleiotropic effect that may be context-dependent.

Ischemic stroke incidence in Santa Coloma de Gramenet (ISISCOG), Spain. A community-based study

Background

In Spain, stroke is one of the major causes of death and the main cause of severe disability in people over 65 years. We analyzed the incidence of ischemic stroke, stroke subtypes, case fatality and disability at 90 days after the event in a Spanish population.

Methods

A prospective community-based register of ischemic strokes was established in Santa Coloma de Gramenet (Barcelona) [116,220 inhabitants of all ages, according to the municipal census of December 31,2001], from January 1 to December 31, 2003.

Standard definitions and case finding methods were used to identify all cases in all age groups. Every patient underwent a complete clinical evaluation and systematic tests including neuroimaging (CT/MRI) and vascular studies (carotid duplex ultrasound intra and extracranial and MR angiography).

Results

Over a one year period, 196 ischemic strokes were registered [107 men; median age = 76 years (range 39–98)], being the first event in 159 patients (81.1%) and a recurrent stroke in 37 (18.9%). After age-adjustment to the European population, the incidence of ischemic stroke per 100,000 inhabitants was 172 (95% CI, 148–196); 219 (176–261) in men and 133 (105–160) in women, with an annual incidence for first ischemic stroke of 139 (118–161); 165 (128–201) in men and 115 (89–140) in women. The incidence of stroke increased with age.

Stroke subtypes (TOAST classification criteria) were lacunar in 28.8%, atherothrombotic in 18.6%, cardioembolic in 26.6% and undetermined in 26.0% of patients. At 90 days, the case-fatality was 12%, and among survivors, moderate-to-severe disability was present in 45 % at 3 months.

Conclusion

This prospective community-based study shows one of the lowest incidences of stroke in Europe, as well as one of the lowest case fatality and disability rates at 90 days after stroke.

Validation of ICD-9 codes with a high positive predictive value for incident strokes resulting in hospitalization using Medicaid health data

PURPOSE

To validate ICD 9 codes with a high positive predictive value (PPV) for incident strokes. The study population consisted of Tennessee Medicaid enrollees aged from 50 to 84 years.

METHODS

We identified all patients who were hospitalized with a discharge diagnosis of stroke between 1999 and 2003 using highly specific codes (ischemic stroke ICD 9-CM codes 433.x1, 434 [excluding 434.x0], or 436; intracerebral hemorrhage [431]; and subarachnoid hemorrhage [430]). We reviewed medical records of a systematic sample of 250 cohort members. We randomly selected 10-30 eligible records for review from hospitals with at least 10 stroke hospitalizations.

RESULTS

We reviewed 231 charts (93% of total sampled), and 205 (89%) met study criteria for new outpatient stroke. Of the 205 confirmed new outpatient strokes, 196 had stroke listed as the primary discharge diagnosis (PPV = 96%). However, 46 (23%) of the 196 patients identified by the primary diagnosis also had a remote stroke history (recurrent stroke not incident). Thus the PPV of the primary discharge diagnosis for identifying incident stroke decreased to 74%. When we applied an algorithm that restricted our population to those with stroke as the primary diagnosis and excluded patients with any prior outpatient diagnosis of stroke, we identified incident stroke events with more precision (PPV = 80%).

CONCLUSION

The PPV of incident strokes was 80% using our strategy of primary discharge diagnosis and excluding prior outpatient diagnoses of stroke. Although an unknown percentage of incident strokes are missed, this group of proven incident stroke patients can be used for etiologic studies of medication exposures.

Recent epidemiological trends of stroke

OBJECTIVE

Rapid increase in aged population and westernization of lifestyle have modified epidemiological status of stroke. The purpose of this study is to analyze changing trends of stroke epidemiology in South Korea.

METHODS

We reviewed retrospectively medical records of 1,124 cases diagnosed as stroke among 54,534 patients who visited the Emergency Medical Center at our hospital from January 1994 to December 1996 (Group A). Also, we evaluated 1,705 cases diagnosed as stroke among 55,381 patients who visited to the same hospital from January 2003 to December 2005 (Group B). The variable features of stroke, such as age, sex, seasonal variation and distribution of stroke subtypes were studied by comparing group A with B.

RESULTS

In group A, hemorrhagic stroke (67.9%) was more prevalent than ischemic stroke (32.1%). However, group B showed that the ratio of hemorrhagic stroke (40.3%) to ischemic stroke (59.6%) has been reversed. The highest incidence of stroke was noted in their sixties and seventies of age in group B, which was older than that of group A. In group A, male ischemic stroke (IS) patients outnumbered female patients (1.26:1). Moreover, this gender disproportion became higher in group B (1.53:1). In group A, the number of male intracerebral hermorrhage (ICH) patients were similar to that of female patients (0.97:1). However, male ICH patients outnumbered female patients in group B (1.23:1). As for subarachnoid hemorrhage (SAH), female patients outnumbered male patients more than two-fold in both groups. Both groups showed that the occurrence of ischemic stroke was highest in summer, but that of hemorrhagic stroke was the highest in winter.

CONCLUSION

This study showed the changing trends of stroke in its distribution of subtypes. Multicenter prospective study using stroke registry would be required for the determination of national epidemiologic trends.

Alcohol consumption and risk for stroke among Chinese men

OBJECTIVE

Stroke is a leading cause of death and long-term disability in China. The objective of this study was to examine the relation between alcohol consumption and risk for stroke among Chinese men.

METHODS

We conducted a prospective cohort study among 64,338 Chinese men aged > or = 40 years who were free of stroke at baseline. Data on frequency and type of alcohol consumed were collected at the baseline examination in 1991 using a standard protocol. Follow-up evaluation was conducted in 1999 to 2000, which included determining vital status, interviewing participants or proxies, and obtaining hospital and medical records for incident and fatal strokes.

RESULTS

Over the course of 493,351 person-years of follow-up, we documented 3,434 incident strokes (1,848 stroke deaths). After adjustment for age, body mass index, physical activity, urbanization (urban vs rural), geographic variation (north vs south), cigarette smoking, history of diabetes, and education, compared with nondrinkers, relative risk (95% confidence interval) of incident stroke was 0.92 (0.80-1.06) for participants consuming 1 to 6 drinks/week, 1.02 (0.93-1.13) for those consuming 7 to 20 drinks/week, 1.22 (1.07-1.38) for those consuming 21 to 34 drinks/week, and 1.22 (1.08-1.37) for those consuming 35 or more drinks per week (p for linear trend < 0.0001). The corresponding relative risks for stroke mortality were 0.93 (0.76-1.14), 0.98 (0.85-1.13), 1.15 (0.95-1.38), and 1.30 (1.11-1.52), respectively (p for linear trend = 0.0004; p for quadratic trend = 0.03).

INTERPRETATION

These results suggest that heavy alcohol drinking may increase the risk for stroke in Chinese men and should be the target of strategies for prevention.

Regional differences in African Americans' high risk for stroke: the remarkable burden of stroke for Southern African Americans

PURPOSE

The stroke mortality rate for African Americans aged 45 to 64 years is 3 to 4 times higher than for whites of the same age, with a decreasing black-to-white mortality ratio with increasing age. There is also a "STROKE BELT" with higher stroke mortality in the southeastern United States. This study assesses if there are also geographic variations in the magnitude of the excess stroke mortality for African Americans.

METHODS

The age- and sex-specific black-to-white mortality ratio was calculated for each of 26 states with a sufficient African American population for stable estimates. The southern excess was calculated as the percentage excess of southern over nonsouthern rates.

RESULTS

Across age and sex strata, the black-to-white stroke mortality ratio was consistently higher for southern states, with an average black-to-white stroke mortality ratio that ranged from 6% to 21% higher among southern states than in nonsouthern states.

CONCLUSIONS

The increase in stroke mortality rates for African Americans in southern states is even larger than expected. That southern states that are not part of the "STROKE BELT" (Virginia and Florida) also have an elevated black-to-white mortality ratio suggests the mechanism of higher risk for African Americans may be independent of the causes contributing to "STROKE BELT."

Willingness of ischemic stroke patients to donate DNA for genetic research: a systematic review

Systematic differences between eligible subjects who participate in research and those who do not are a form of selection bias. The aim of this study was to determine whether published reports of genetic studies of stroke provide sufficient information on the willingness of subjects to participate to assess the potential for bias. We conducted a systematic 2-person review of the English-language literature based on a MEDLINE search for studies on the genetics of ischemic stroke published between January 2000 and January 2002. Of the 41 studies that met the search criteria, only 6 (15%) provided information on the number of stroke patients who were eligible for DNA collection but refused to donate a DNA sample: 4 hospital-based case-control studies or case series and 2 population-based case-control studies of 1 cohort. The acceptance rate for participation was higher in the hospital-based case-control studies (95-99%) than in the population-based studies (75.2%). Scant data are available regarding the willingness of patients with ischemic stroke to participate in genetic studies. Methodologic and cultural differences may explain the broad range of acceptance rates for participation.

Specific P-selectin and P-selectin glycoprotein ligand-1 genotypes/haplotypes are associated with risk of incident CHD and ischemic stroke: the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

P-selectin (PSEL) and its ligand, P-selectin glycoprotein ligand-1 (PSGL-1), play key roles in both the inflammatory response and the atherosclerotic process, but there are conflicting results regarding the affect of PSEL and PSGL-1 gene variation on risk for cardiovascular and cerebrovascular disease. We tested the association of four PSEL and two PSGL-1 polymorphisms with incident coronary heart disease (CHD) and ischemic stroke among 13,875 participants in the prospective Atherosclerosis Risk in Communities (ARIC) study. We also tested common haplotypes in the PSEL and PSGL-1 genes to assess associations with incident CHD and ischemic stroke.

METHODS AND RESULTS

Incident ischemic stroke and CHD were identified through annual telephone calls and hospital and death certificate surveillance. Five hundred and twenty-five validated ischemic stroke and 1654 CHD events were identified. Allele frequencies for all PSEL and PSGL-1 polymorphisms were markedly different between whites and African Americans; therefore, all analyses were performed race-specific. Independent analyses showed the PSEL 290NN genotype to be a significant predictor of CHD in whites (HRR 1.30, 95%CI 1.00-1.70, P=0.05). PSGL-1 genotypes carrying the 62I allele were significantly protective for incident CHD (HRR 0.53, 95%CI 0.31-0.92, P=0.02) and ischemic stroke (HRR 0.73, 95%CI 0.55-0.97, P=0.03) in African Americans. Haplotype analyses showed the PSEL NNVP haplotype to be a significant predictor of incident CHD in whites (HRR 2.09, 95%CI 1.23-3.55, P=0.006). No significant haplotype findings were observed in African Americans.

CONCLUSIONS

PSEL S290N, in single polymorphism analysis and in the haplotypic background with T715P, was associated with increased risk of incident CHD in whites. The PSGL-1 M62I polymorphism was associated with decreased risk of both incident CHD and stroke in African Americans. These findings illustrate the complex relationship between genetic variation and disease in different racial groups.

Echocardiographic left ventricular mass index predicts incident stroke in African Americans: Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND PURPOSE

Despite theories that link stroke to left ventricular mass, few large, population-based studies have examined the predictive value of echocardiographically derived left ventricular mass index (LVMI) to incident stroke in African Americans.

METHODS

Participants in the Jackson cohort of the Atherosclerotic Risk in Communities study have had extensive baseline evaluations, have undergone echocardiography during the third examination (1993-1995), and have been followed up for incident cardiovascular disease including ischemic stroke.

RESULTS

The study population consisted of 1792 participants, of whom 639 (35.7%) were men and the mean+/-SD age was 58.8+/-5.7 years. Compared with those without ischemic stroke, those with ischemic stroke had a higher frequency of hypertension (85.6% vs 58.7%) and diabetes (46.9% vs 21.0%). Left ventricular hypertrophy was more prevalent in those with stroke (62.2% vs 38.6%). During a median follow-up of 8.8 years, 98 incident strokes occurred (6.5 per 1000 person-years). LVMI was independently associated with stroke after adjusting for age, sex, hypertension, systolic blood pressure, smoking, diabetes, total to HDL cholesterol ratio, body mass index, and low left ventricular ejection fraction (adjusted hazard ratio per 10 g/m(2.7) increment of LVMI=1.15; 95% CI, 1.02 to 1.28). The relation remained statistically significant after adding left atrial size and mitral annular calcification to the multivariable model.

CONCLUSIONS

In this large, population-based African American cohort, we found that echocardiographic LVMI was an independent predictor of incident ischemic stroke even after taking into account traditional clinical risk factors.

Ethnic differences in risk factors for subarachnoid hemorrhage

Object

Studies on risk factors for subarachnoid hemorrhage (SAH) show heterogeneity. For example, hypertension has been found to be a significant risk factor in some studies but not in others. The authors hypothesized that differences in the ethnicity of the populations studied could account for these findings.

Methods

A metaanalysis was performed using 17 case-control and 10 cohort studies that met specified inclusion criteria. The authors used a random-effect model to calculate the pooled effect estimates for current smoking, hypertension, and alcohol consumption. A meta–regression analysis was performed using the ethnic composition of the study populations as a covariate. Studies were classified as multiethnic or monoethnic, and the pooled effect estimates were compared.

Results

Analysis of the cohort studies yielded a pooled effect estimate or risk ratio of 3.18 (95% confidence interval [CI] 2.37–4.26) for current smoking, 3.05 (95% CI 2.09–4.44) for hypertension, and 2.46 (95% CI 1.42–4.24) for alcohol consumption at a rate of 150 g/week or more. The results were similar for the case-control studies. For current smoking, the ethnic composition of the study population was a statistically significant predictor of heterogeneity among case-control studies (p < 0.001, even after application of the Bonferroni correction). The risk for SAH among current smokers was higher in multiethnic populations (odds ratio 3.832) than in monoethnic populations (odds ratio 2.487).

Conclusions

The results of this metaanalysis suggest that differences in susceptibility to the harmful health effects of smoking may be one cause of the observed differences in SAH incidence for different ethnic groups. The role of ethnicity in risk factors for SAH should be considered in future studies.

Cost-effectiveness of antiplatelet therapy for secondary stroke prevention

Antiplatelet therapy is recommended over anticoagulants for the secondary prevention of vascular death in patients with noncardioembolic ischemic stroke or transient ischemic attack based upon the 2006 American Heart Association/American Stroke Association guidelines for the prevention of stroke and the National Stroke Association guidelines for the management of transient ischemic attack. Aspirin is commonly used as a cornerstone antiplatelet agent considering its mild but definite prevention benefit and low costs. Other antiplatelet strategies that are currently recommended include extended-release dipyridamole plus low-dose aspirin (Aggrenox((R)), Asasantin((R))) and clopidogrel. In this brief review, we evaluate the cost-effectiveness of antiplatelet agents for secondary stroke prevention to better understand the socioeconomical value of the recommended agents.

An economic model of long-term use of celecoxib in patients with osteoarthritis

Background

Previous evaluations of the cost-effectiveness of the cyclooxygenase-2 selective inhibitor celecoxib (Celebrex, Pfizer Inc, USA) have produced conflicting results. The recent controversy over the cardiovascular (CV) risks of rofecoxib and other coxibs has renewed interest in the economic profile of celecoxib, the only coxib now available in the United States. The objective of our study was to evaluate the long-term cost-effectiveness of celecoxib compared with nonselective nonsteroidal anti-inflammatory drugs (nsNSAIDs) in a population of 60-year-old osteoarthritis (OA) patients with average risks of upper gastrointestinal (UGI) complications who require chronic daily NSAID therapy.

Methods

We used decision analysis based on data from the literature to evaluate cost-effectiveness from a modified societal perspective over patients' lifetimes, with outcomes expressed as incremental costs per quality-adjusted life-year (QALY) gained. Sensitivity tests were performed to evaluate the impacts of advancing age, CV thromboembolic event risk, different analytic horizons and alternate treatment strategies after UGI adverse events.

Results

Our main findings were: 1) the base model incremental cost-effectiveness ratio (ICER) for celecoxib versus nsNSAIDs was $31,097 per QALY; 2) the ICER per QALY was $19,309 for a model in which UGI ulcer and ulcer complication event risks increased with advancing age; 3) the ICER per QALY was $17,120 in sensitivity analyses combining serious CV thromboembolic event (myocardial infarction, stroke, CV death) risks with base model assumptions.

Conclusion

Our model suggests that chronic celecoxib is cost-effective versus nsNSAIDs in a population of 60-year-old OA patients with average risks of UGI events.

Interaction effects of high-density lipoprotein metabolism gene variation and alcohol consumption on coronary heart disease risk: the atherosclerosis risk in communities study

OBJECTIVE

Light to moderate alcohol consumption has been widely established to be protective against coronary heart disease (CHD), whereas heavy alcohol consumption has been shown to have a potential detrimental effect. The reduction in risk of CHD associated with light and moderate alcohol intake is generally attributed to the beneficial effects of alcohol on high-density lipoprotein (HDL) cholesterol levels. Previous research in the Atherosclerosis Risk in Communities (ARIC) study showed all levels of alcohol consumption to be protective against CHD in whites but to be associated with an increased risk of CHD in black men. We investigated the ARIC cohort to determine whether risk of incident CHD is influenced by an interaction effect between alcohol intake and genetic variation involved in the regulation of HDL cholesterol. Genes of interest included cholesterol ester transfer protein (CETP), lipoprotein lipase (LPL), hepatic lipase (HL), and paraoxonase-1 (PON1).

METHOD

Participants were selected from the ARIC study, a prospective investigation of atherosclerosis and its clinical sequelae, involving 15,792 individuals, ages 45-64 years at recruitment (1987-1989). Incident CHD was identified through annual telephone calls and hospital and death certificate surveillance. Because of ethnic differences in the alcohol-CHD relationship observed in the ARIC cohort and pattern of alcohol consumption differences, statistical analyses were evaluated separately for each race-gender stratum (white men/women, black men/women).

RESULTS

Genotype modified the relationship between heavy drinking and CHD risk but did not modify this relationship for light or moderate drinking. Interaction analyses were significant for heavy alcohol intake and PON1 genotype (p=.02) in black men, with a suggested interaction for heavy alcohol intake and CETP genotype (p=.06) in black men. Heavy drinking was associated with an increased risk for CHD in black men with the PON1 QQ and CETP GG genotypes (PON1 hazard rate ratio [HRR]=17.3, 95% confidence interval [CI]: 1.76-170.2; CETP HRR=2.23, 95% CI: 1.01-4.91).

CONCLUSIONS

Results from the current study suggest that interaction effects between alcohol consumption and HDL cholesterol metabolism gene variation influence the risk of incident CHD in black men. Additional studies are warranted to confirm these findings.

Morphological alteration of Golgi apparatus and subcellular compartmentalization of TGF-beta1 in Golgi apparatus in gerbils following transient forebrain ischemia

Golgi apparatus (GA) is a very important organelle involved in the metabolism of numerous proteins. TGF-beta1 plays an important role in supporting neuronal survival after ischemic insults. Little is known, however, about the morphological alteration of GA and subcellular compartmentalization of TGF-beta1 in brain after ischemia. Therefore, our present study was designed to check for GA morphological alterations and TGF-beta1 subcellular localization. GA immunoreactivities were examined in the somatosensory cortex of gerbils after 10 min transient forebrain ischemia. Confocal Immunofluorographs of TGF-beta1 and TGN38 were also taken. Results indicated that no fragmentation of GA was found in gerbils of norm, shams and 6, 24 and 72 h postocclusion, but some of the cortical cells showed fragmentation of GA in gerbils 7 days postocclusion. TGF-beta1 was colocalized with TGN38, a marker molecule for the GA. We conclude that there was morphological alterations of GA and TGF-beta1 was present in GA in the somatosensory cortex after 10 min ischemia.

Convulsive status epilepticus after ischemic stroke and intracerebral hemorrhage: frequency, predictors, and impact on outcome in a large administrative dataset

OBJECTIVE

Relatively little is known about the epidemiology of generalized convulsive status epilepticus (GCSE) in acute ischemic and hemorrhagic stroke. We examined the occurrence of GCSE in acute ischemic stroke (AIS) and intracerebral hemorrhage (ICH) using a large discharge database.

METHODS

Data were derived from the Nationwide Inpatient Sample for the years 1994-2002. Using the appropriate ICD-9-CM codes, patients admitted through the emergency room with a diagnosis of AIS or ICH were selected for analysis. From these patients, those coded as having GCSE were identified. Multivariate logistic regression was performed using clinical elements available in the database to identify independent predictors of GCSE. The association between GCSE and various outcome measures was also assessed.

RESULTS

The cohort included 718,531 hospitalizations with AIS and 102,763 with ICH. GCSE developed in 1,415 (0.2%) of the AIS cohort and 266 (0.3%) of the ICH cohort. For the AIS cohort, female sex, African American race, renal disease, alcohol abuse, sodium imbalance, and hemorrhagic transformation were associated with higher rates, while increasing age, hypertension, and diabetes mellitus were associated with lower rates of GCSE. For the ICH cohort, African American and Hispanic race, renal disease, coagulopathy, brain tumor, alcohol abuse, and sodium imbalance were associated with higher rates, while increasing age and hypertension were associated with lower rates of GCSE. GCSE was associated with higher rates of adverse outcomes.

CONCLUSIONS

GCSE is a rare but serious complication in the setting of acute ischemic stroke and intracerebral hemorrhage.

Racial differences in hospital discharge disposition among stroke patients in Maryland

OBJECTIVE

The objective of this retrospective study was to assess the evidence for racial differences in discharge disposition among patients hospitalized for stroke.

DATA

Hospital discharge data from the Maryland Health Services Cost Review Commission were used in the analysis. The data covered the period from January 2000 to September 2003.

STUDY DESIGN

Discharge-disposition categories were ordered such that higher numbers corresponded to less desirable outcomes: 1 = discharge to home; 2 = discharge to any medical care facility; 3 = death. We analyzed the influence of black race on the discharge disposition by estimating a partial proportional odds logit regression model that included demographic and clinical covariates.

DATA EXTRACTION

The study inclusion criteria were 1) stroke (ICD9 431-434; 436-438) as a primary admission diagnosis and 2) patient race identified as black or white. Patients discharged against medical advice were excluded. The sample contained 51,564 stroke hospitalizations.

PRINCIPAL FINDINGS

Based on the relative odds ratios (OR; 95% confidence interval [CI]), black males were more likely to be discharged to higher ranked (i.e., less desirable) discharge categories (OR = 1.66; CI 1.55-1.77) compared to white males. Black females were more likely to die (OR = 1.14; CI 1.02-1.28) and more likely either to die or to be discharged to medical care (OR = 1.38; CI 1.24-1.54) compared to white males.

CONCLUSIONS

Blacks are at greater mortality risk following stroke hospitalizations and face less desirable discharge dispositions if they survive. These results are consistent with prior reports of lower survival rates among blacks and are robust to adjustments for various confounding factors.

Cyclooxygenase polymorphisms and risk of cardiovascular events: the Atherosclerosis Risk in Communities (ARIC) study

Cyclooxygenase-derived prostaglandins modulate cardiovascular disease risk. We genotyped 2212 Atherosclerosis Risk in Communities study participants (1,023 incident coronary heart disease (CHD) cases; 270 incident ischemic stroke cases; 919 non-cases) with available DNA for polymorphisms in PTGS1 and PTGS2. Using a case-cohort design, associations between genotype and CHD or stroke risk were evaluated using proportional hazards regression. In Caucasians, the reduced function PTGS1 -1006A variant allele was significantly more common among stroke cases compared to non-cases (18.2 versus 10.6%, P=0.027). In African Americans, the reduced function PTGS2 -765C variant allele was significantly more common in stroke cases (61.4 versus 49.4%, P=0.032). No significant relationships with CHD risk were observed. However, aspirin utilization appeared to modify the relationship between the PTGS2 G-765C polymorphism and CHD risk (interaction P=0.072). These findings suggest that genetic variation in PTGS1 and PTGS2 may be important risk factors for the development of cardiovascular disease events. Confirmation in independent populations is necessary.

Stroke in China: epidemiology, prevention, and management strategies

In this review, we examine the current status of stroke epidemiology, prevention, and management strategies in mainland China. The main findings suggested that total age-adjusted incidence of first-ever stroke in China is not very different from that in developed countries. Stroke incidence, mortality, and prevalence varied widely among different regions within China, with a noticeable north-south gradient. The proportion of intracerebral haemorrhage was high and reached 55% in one city. Hypertension is the most important risk factor for stroke. The mass approach combined with a high-risk approach for stroke prevention showed encouraging effects, and various unconventional local therapeutic traditions are commonly used to treat stroke in China. Several national guidelines on stroke prevention and treatment have been developed. Because of methodological limitations in the epidemiology studies, data are unreliable in terms of making any firm conclusions. Up-to-date, well-designed, and well-done epidemiological studies and therapeutic trials in China are urgently needed.

Does statin therapy decrease the risk for bleeding in patients who are receiving warfarin?

PURPOSE

Recent observations in patients with atrial fibrillation who are receiving warfarin suggest that concomitant treatment with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) decreases the risk for bleeding.

METHODS

We conducted a population-based, nested case-control study using the linked administrative databases of Ontario, Canada, to assess whether statin use decreases the risk of bleeding in warfarin users. Eligible patients were Ontario residents, age 66 years or more, with atrial fibrillation who were prescribed warfarin between April 1, 1994, and December 31, 2001. Patients were followed until hospitalization for upper gastrointestinal or intracranial bleeding, study end (March 31, 2002), discontinuation of warfarin, or death. Cases were matched to controls by age and sex. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between bleeding and statin use.

RESULTS

We identified 79,207 warfarin users with atrial fibrillation. There were 1518 cases with an upper gastrointestinal or intracranial bleed and 15,100 matched controls without bleeding. Long-term (>/=1 year) statin use was associated with a lower risk for any bleeding (OR=0.80; 95% CI, 0.66-0.97). However, there was no association between bleeding and recent (<6 months) statin use (OR=1.04; 95% CI, 0.74-1.48) or statin use of any duration (OR: 0.91; 95% CI, 0.77-1.07), suggesting potential confounding of the association between statin use and bleeding by a health-user effect.

CONCLUSION

Long-term statin use may be associated with a decreased risk for bleeding in warfarin users with atrial fibrillation. Additional research is needed to further explore this putative association.

Characterization of a thromboembolic photochemical model of repeated stroke in mice

Many stroke research groups utilize the model of middle cerebral artery occlusion induced by insertion of an intraluminal thread, owing to its pragmatism and reliability of cerebral infarct generation. However, 75% of stroke cases result from a thromboembolic event and 10% from occlusive atherothrombosis in situ. Here, we characterize a mouse model of repeated thromboembolic stroke, which closely mimics the intravascular pathophysiology of arterial thrombus generation from an atherosclerotic plaque, and subsequent release of a thrombus into the cerebral circulation as an embolus. Common carotid artery thrombosis (CCAT) was induced photochemically leading to non-occlusive platelet aggregation in C57/BL6 male mice (n=35), and was followed by mechanical assistance to facilitate release of the thrombus (MRT) and thus promote embolism. Six experimental groups, differing by changes in the surgical protocol, were used for the purpose of determining which such procedure yielded the most reliable and consistent brain infarct volumes with the lowest mortality at 3 days after surgery. The group which best satisfied these conditions was a double insult group which consisted of animals that underwent CCAT for 2 min by means of argon laser irradiation (514.5 nm) at an intensity of ca. 130 W/cm(2), with concomitant injection of erythrosin B (EB) (35 mg/kg infused over those same 2 min), followed by MRT 1 min later; the entire procedure was repeated 24h later. This group showed a percent of brain lesion volume of 15+/-4% (mean+/-S.D.) with no associated 3-day mortality. Compared to a single insult group which sustained a percent brain lesion volume of 7+/-3%, there was a statistically significant (p<0.05) increase in the volume of infarction in the double-insult group.

In-hospital onset ischemic stroke may be associated with atrial fibrillation and right-to-left shunt

BACKGROUND AND PURPOSE

Ischemic stroke during hospitalization can occasionally be found, but the mechanisms and causes underlying stroke have not been investigated in detail. The present study aimed to identify differences in stroke etiology between in-hospital and out-of-hospital onset.

METHODS

Subjects comprised 357 consecutive patients (221 men, 136 women) with ischemic stroke prospectively enrolled within 24 h of onset. Contrast saline transcranial Doppler ultrasonography (c-TCD) or transesophageal echocardiography (TEE) was performed in all participants to identify right-to-left shunts (RLS). Patients were divided into 2 groups: in-hospital onset (IHO group, n=49); and out-of-hospital onset (OHO group, n=308). Clinical characteristics were compared between groups.

RESULTS

Mean age was 71.5+/-12.3 years. Mean National Institute of Health stroke scale score was 6.9+/-7.2. RLS, atrial fibrillation (AF) and malignancy were more frequent in the IHO group than in the OHO group (39% vs. 20%, p=0.006; 45% vs. 16%, p<0.001; 18% vs. 4%, p<0.001, respectively). AF and/or RLS was more frequent in the IHO group (61%) than in the OHO group (30%, p<0.001).

CONCLUSION

Ischemic stroke with in-hospital onset may be associated with AF and RLS.

NOS3 polymorphisms, cigarette smoking, and cardiovascular disease risk: the Atherosclerosis Risk in Communities study

OBJECTIVE

Endothelial nitric oxide synthase (NOS3) activity and cigarette smoking significantly influence endothelial function. We sought to determine whether cigarette smoking modified the association between NOS3 polymorphisms and risk of coronary heart disease or stroke.

METHODS

All 1085 incident coronary heart disease cases, all 300 incident ischemic stroke cases, and 1065 reference individuals from the Atherosclerosis Risk in Communities study were genotyped for the T-786C and E298D polymorphisms in NOS3. Using a case-cohort design, associations between genotype/haplotype and disease risk were evaluated by multivariable proportional hazards regression. Multiplicative scale interaction testing evaluated the influence of cigarette smoking history at baseline on these associations.

RESULTS

In Caucasians, association between E298D genotype and risk of coronary heart disease was significantly modified by current smoking status (interaction P=0.013), with the highest risk observed in smokers carrying the variant D298 allele relative to nonsmokers carrying two E298 alleles (adjusted hazard rate ratio 2.07, 95% confidence interval 1.39-3.07). In African-Americans, association between T-786C genotype and risk of ischemic stroke was significantly modified by pack-year smoking history (interaction P=0.037), with the highest risk observed in >or=20 pack-year smokers carrying the variant C-786 allele relative to <20 pack-year smokers carrying two T-786 alleles (adjusted hazard rate ratio 4.03, 95% confidence interval 1.54-10.6).

CONCLUSIONS

An interaction between the E298D and T-786C polymorphisms in NOS3, cigarette smoking, and risk of incident coronary heart disease and ischemic stroke events appears to exist, suggesting a potential complex interplay between genetic and environmental factors and cardiovascular disease risk.

Lung function and ischemic stroke incidence: the Atherosclerosis Risk in Communities study

BACKGROUND

Few studies have examined the relation between lung function and ischemic stroke incidence; none have studied African Americans.

METHODS

We followed 13,842 middle-aged adults initially free of stroke and coronary heart disease and observed 472 incident ischemic strokes over 13 years. Quartiles of FEV(1) as a percentage of predicted value (FEV(1)PP) and FVC as a percentage of a predicted value (FVCPP) were used as the indicators of lung function.

RESULTS

In the age-, race-, gender-, and education-adjusted models, both lung function measures were significantly inversely related to ischemic stroke incidence (linear trend for FEV(1)PP, p < 0.01; linear trend for FVCPP, p < 0.01), but adjustment for possible confounders attenuated these relations. For white subjects, a significant inverse relation remained even after full adjustment (relative hazards [RH] across FEV(1)PP quartiles (lowest to highest) were 1.59, 1.52, 1.26, and 1.00; and for FVCPP quartiles were 1.56, 1.80, 1.09, and 1.00 [trend for both, p < 0.05]). There was no association for African Americans (RH across FEV(1)PP and FVCPP quartiles were 0.74, 0.89, 0.73, 1.00 [linear trend, p = 0.27] and 0.81, 1.07, 0.61, 1.00 [linear trend, p = 0.75], respectively). An inverse relation between lung function and ischemic stroke was also observed among white subjects who never smoked (FEV(1)PP) or had no respiratory symptoms (both FEV(1)PP and FVCPP) but not among their African-American counterparts.

CONCLUSIONS

Among white subjects, participants with impaired lung function have a modestly higher risk of ischemic stroke even if they have never smoked nor had respiratory symptoms.

A review of stroke in patients with hypertension and coronary artery disease: Focus on calcium channel blockers

Stroke is a major cause of morbidity and mortality worldwide. Hypertension is one of the most important risk factors for stroke - increasing the risk significantly. The presence and severity of coronary artery disease (CAD), which often coexists with hypertension, also predicts an increased risk of stroke. Lowering blood pressure (BP) to target in patients with hypertension can significantly reduce the incidence of fatal and non-fatal stroke. Effective BP control is even more important in CAD patients who are at greater risk of stroke. Data regarding the effects of antihypertensive therapy on stroke in patients with angina or CAD are limited and have been variable. To date, BP management strategies in patients with CAD have relied on small subsets of data based on high-risk hypertensive patients. Results with calcium channel blockers (CCBs) have been more positive than those with other classes of antihypertensive agents. Findings from the ACTION trial have provided a significant insight into the benefits of CCBs in patients with CAD and hypertension. Nifedipine gastrointestinal therapeutic system (GITS), in addition to best practice therapy for stable angina pectoris, contributes to a significant reduction in the risk of stroke in patients with CAD and hypertension who are at high risk and require effective BP control. Moreover, the incidence of stroke is significantly related to baseline BP, which may be an important factor to consider when deciding on treatment strategies in high-risk patients with CAD.

Prospective study of subclinical atherosclerosis as a risk factor for venous thromboembolism

BACKGROUND

Whether atherosclerotic disease predisposes to venous thrombosis is uncertain.

OBJECTIVE

To determine whether subclinical atherosclerosis, manifested as increased carotid intima-media thickness (IMT) or presence of carotid plaque, is associated with increased incidence of venous thromboembolism (VTE).

PATIENTS AND METHODS

The Atherosclerosis Risk in Communities study is a prospective cohort of adults aged 45-64 years, examined at baseline (1987-89) and followed for cardiovascular events. Bilateral carotid ultrasound for IMT measurements was done at baseline for portions of the common and internal carotid arteries, and carotid bifurcation and also to detect the presence of carotid plaque. Exclusion criteria included baseline anticoagulant use, history of coronary heart disease, stroke, or VTE, and incomplete data. First VTE during follow-up was validated using abstracted medical records.

RESULTS

Among 13,081 individuals followed for a mean of 12.5 years, 225 first VTE events were identified. Unadjusted hazard ratios (HR) (95% CI) of VTE across quartiles of baseline IMT were 1.0, 1.16 (0.77-1.75), 1.64 (1.12-2.40), and 1.52 (1.03-2.25). However, this association disappeared after adjustment for age, sex, and ethnicity (HRs: 1.0, 1.06, 1.40, and 1.18). Further adjustment for body mass index and diabetes weakened the relative risks even further. Presence of carotid plaque at baseline also was not associated with VTE occurrence; adjusted HR = 0.97, 95% CI = 0.72-1.29.

CONCLUSION

Increased carotid IMT or presence of carotid plaque was not associated with an increased incidence of VTE in this middle-aged cohort, suggesting subclinical atherosclerosis itself is not a VTE risk factor.

Impact of rosuvastatin use on costs and outcomes in patients at high risk for cardiovascular disease in US managed care and medicare populations: A data analysis

BACKGROUND

High blood cholesterol is a major modifiable risk factor for coronary heart disease (CHD) and stroke.

OBJECTIVE

The aim of this study was to estimate the economic impact of rosuvastatin calcium use in patients at high risk for CHD and stroke, according to the National Cholesterol Education Program Adult Treatment Panel (ATP) III guidelines.

METHODS

An economic simulation model was developed that used a Markov process to project the number of cardiovascular events and associated costs in a high-risk population in various treatment scenarios. According to the ATP III, high-risk patients are those with CHD, atherosclerosis of peripheral and/or cerebral arteries, diabetes, and/or multiple other risk factors conferring a risk of at least 20% within 10 years. Data on population characteristics and costs of cardiovascular disease (CVD) were obtained from claims data sets from employer-funded commercial and Medicare health plans in the United States. Treatment of lipid disorders was translated into CVD risk reduction based on results from the Heart Protection Study. The estimated efficacies of individual lipid-lowering drugs were based on data published in package inserts. The model generated costs at the health plan level of lipid-lowering therapy in high-risk patients and the number and total costs of cardiovascular events. Estimates were compared for scenarios representing the mix of treatments used before and after the introduction of rosuvastatin. Estimates were generated separately for commercial and Medicare health plans.

RESULTS

For every 1 million members of a commercial health plan, an estimated 44,457 met ATP III criteria for high-risk status. Use of rosuvastatin in place of other 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins") by 11 % of these patients over a period of 5 years was estimated to result in 36 fewer cardiovascular events and a net savings of US 4.03 million dollars. A Medicare plan of 1 million members with an estimated 433,268 high-risk patients and 7% rosuvastatin use was estimated to avoid 727 events and save US 34.32 million dollars.

CONCLUSIONS

The results of this data analysis suggest that increasing the use of rosuvastatin can result in cardiovascular event reduction and cost savings. Because the impact of lipid-modifying therapy on cardiovascular risk has not been thoroughly documented in controlled clinical studies, our model assumed that incremental lipid changes had effects in proportion to the magnitude of change.

Safety, tolerability and pharmacokinetics of escalating doses of NXY-059 in healthy young and elderly subjects

OBJECTIVE

NXY-059 is a novel, free-radical trapping, neuroprotectant that reduces infarct size and preserves brain function in animal models of acute ischaemic stroke. This study evaluated the safety, tolerability and pharmacokinetics of NXY-059 in the unbound steady-state plasma concentration (Cu(ss)) exposure range of 50-300 micromol/L in healthy young and elderly subjects.

RESEARCH DESIGN AND METHODS

The primary objective of this two-centre, randomised, double-blind, placebo-controlled, dose-escalating study was to investigate the safety and tolerability, including renal function parameters and vasoirritative effects, of 8-h and 72-h intravenous infusions of NXY-059 in healthy young (20-45 years) and elderly (55-75 years) male and female subjects. The secondary objective of the study was to evaluate the pharmacokinetics of 8-h and 72-h intravenous infusions of NXY-059 in these subjects, using blood and urine samples taken during and after NXY-059 infusion as well as the doses administered.

RESULTS

Of the 104 healthy volunteers who participated in the study, 72 were young and 32 were elderly. The type and incidence of adverse events in NXY-059 and placebo subjects were similar, although headache was more common in the NXY-059 group. Renal function was not altered in either group. Thrombophlebitis was reported in two elderly subjects: one receiving NXY-059 and one receiving placebo. A proportional relationship between AUC and dose for the 8-h and 72-h infusions was observed, and clearance did not change with dose.

CONCLUSIONS

NXY-059 was well tolerated at all plasma concentrations tested in both the young and elderly subjects, and no safety concerns were raised. Linear pharmacokinetics were observed following 8-h and 72-h infusions of NXY-059 at doses resulting in an average Cu(ss) in the 52-317 micromol/L range.

The time course of subsequent hospitalizations and associated costs in survivors of an ischemic stroke in Canada

Background

Documentation of the hospitalizations rates following a stroke provides the inputs required for planning health services and to evaluate the economic efficiency of any new therapies.

Methods

Hospitalization rates by cause were examined using administrative data on 18,695 patients diagnosed with ischemic stroke (first or subsequent, excluding transient ischemic attack) in Saskatchewan, Canada between 1990 and 1995. Medical history was available retrospectively to January 1980 and follow-up was complete to March 2000. Analyses evaluated the rate and timing of all-cause and cardiovascular hospitalizations within discrete periods in the five years following the index stroke. Cardiovascular hospitalizations included patients with a primary diagnosis of ischemic stroke, transient ischemic attack, myocardial infarction, stable or unstable angina, heart failure or peripheral arterial disease.

Results

One-third (36%) of patients were identified by a hospitalized stroke. Mean age was 70.5 years, 48.0% were male, half had a history of stroke or a transient ischemic attack at the time of their index stroke. Three-quarters of the patients (72.7%) were hospitalized at least once during a mean follow-up of 4.6 years, accruing CAD $24 million in the first year alone. Of all hospitalizations, 20.4% were related to cardiovascular disease and 1.6% to bleeds. In the month following index stroke, 12.5% were admitted, an average of 1.04 times per patient hospitalized. Strokes accounted for 33% of all hospitalizations in the first month. The rate diminished steadily throughout the year and stabilized in the second year when approximately one-third of patients required hospitalization, at a rate of about one hospitalization for every two patient-years. Mean lengths of stay ranged from nine days to nearly 40 days. Close-fitting Weibull functions allow highly specific probability estimates. Other cardiovascular risk factors significantly increased hospitalization rates.

Conclusion

After stroke, there are frequent hospitalizations accounting for substantial additional costs. Though these rates drop after one year, they remain high over time. The number of other cardiovascular causes of hospitalization confirms that stroke is a manifestation of disseminated atherothrombotic disease.

Serum uric acid and risk of ischemic stroke: The ARIC Study

AIMS

Since serum uric acid (UA) is strongly associated with cardiovascular risk factors, it has been debated whether serum UA is a stroke risk factor or whether UA may be simply "marking" subjects with other, causal risk factors. We therefore investigated the relation between UA and ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS AND RESULTS

Of 15,792 ARIC participants, 13,413 who were free of recognized stroke or coronary heart disease (CHD) at baseline and had a baseline UA measurement were included in the analysis. We followed the participants for ischemic stroke incidence (N=381) over 12.6 years. Although serum UA was independently and positively related to ischemic stroke incidence when we adjusted for age, sex, race, and education, the positive relation was weakened when additionally adjusted for possible confounding variables. The positive multivariate-adjusted association between serum UA and ischemic stroke was observed among subjects not using diuretics (adjusted relative hazard in the highest quartile versus the lowest: relative hazard (RH)=1.49; 95% confidence interval (CI): 1.00-2.23) (P for trend: 0.02), but not among diuretic users (P for interaction: 0.08).

CONCLUSION

Our findings suggest that UA is an independent predictor of ischemic stroke among subjects not using diuretics, but that elevated UA itself may not cause ischemic stroke.

Trends in hospitalization and mortality for subarachnoid hemorrhage and unruptured aneurysms in the United States

OBJECTIVE

During the past decade, endovascular obliteration of intracranial aneurysms and new treatments for vasospasm and cerebral ischemia have been introduced. To analyze the effectiveness of these new strategies, we evaluated changes in morbidity and mortality rates in patients at least 18 years of age who were hospitalized for ruptured and unruptured intracranial aneurysms during the past 16 years.

METHODS

National estimates of hospitalization for subarachnoid hemorrhage (SAH) and unruptured intracranial aneurysms and associated in-hospital outcomes and mortality were obtained from National Hospital Discharge Survey data. All the variables pertaining to hospitalization were compared for three distinct time periods: 1986-1990, 1991-1995, and 1996-2001.

RESULTS

There were 94,692, 104,746, and 133,269 admissions for SAH during the periods 1986-1990, 1991-1995, and 1996-2001, respectively. Mortality rates for hospitalizations related to SAH demonstrated no significant change in mortality during the periods 1986-1990, 1991-1995, and 1996-2001 (27.6%, 24.6%, and 26.3%, respectively. Procedures performed for SAH from 1996 to 2001 included surgical clipping (28%), endovascular/wrapping (2%), and no procedure (70%). The number of admissions for unruptured intracranial aneurysms was 23,481 from 1986 to 1990, 28,017 from 1991 to 1995, and 51,904 from 1996 to 2001. There was an overall trend (P = 0.07) toward reduced in-hospital mortality during the three periods: 5.9%, 6.3%, and 1.4% for 1986-1990, 1991-1995, and 1996-2001, respectively.

CONCLUSION

The mortality rate for unruptured intracranial aneurysms demonstrates a significant trend of reduction during the past 16 years. The mortality rate for SAH demonstrates limited change during the same period; it is presumed that this is attributable to the multitude of factors that influence outcome.

Clinical significance of a high ankle-brachial index: insights from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

The clinical significance of a high ankle-brachial index (ABI), defined by the associated risk factor burden and ischemic risk, is largely unknown.

METHODS

Using data from the Atherosclerosis Risk in Communities Study, we categorized 14,777 participants into normal (ABI between 0.9 and 1.3) and high ABI groups (ABI>1.3, >1.4, and >1.5) and compared the risk factor profile and CVD event rates of the normal ABI group to each high ABI group.

RESULTS

The prevalence of high ABI was 5.5% for ABI>1.3, 1.2% for ABI>1.4, and 0.37% for ABI>1.5. Compared with participants with a normal ABI, those with ABI>1.3 had a lower prevalence of hypertension and current smoking. The ABI>1.3 group had a greater mean body mass index, but was characterized by fewer pack years of smoking and lower systolic and diastolic blood pressures than the normal ABI group. The prevalence of diabetes, left ventricular hypertrophy, claudication, and coronary heart disease and mean values of fibrinogen, factor VIII activity, von Willebrand factor, lipoprotein (a), and carotid and popliteal intimal-medial thickness were similar between the two ABI groups. The risk factor profiles of the ABI>1.4 and >1.5 groups were also not statistically significantly different from that of the normal ABI group. Over a mean follow-up time of 12.2 years, the age, sex, and race-adjusted CVD event rates per 1000 person years were 8.1 in the normal ABI group, 7.6 in the ABI>1.3 group, 7.6 in the ABI>1.4 group, and 7.4 in the ABI>1.5 group. The CVD event rates of the high ABI groups were similar to that of the normal ABI group.

CONCLUSION

Individuals with a high ABI are not characterized by a more adverse atherosclerosis risk factor profile and do not suffer greater CVD event rates than those with a normal ABI.

A possible explanation for the racial difference in distribution of large-arterial cerebrovascular disease: ancestral European settlers evolved genetic resistance to atherosclerosis, but confined to the intracranial arteries

The pattern of cerebral atherosclerosis is not the same among different races. White patients rarely have intracranial large arterial steno-occlusive disease even if their systemic arteries are extensively involved, while non-white patients frequently have their intracranial arteries affected. We postulate that during human population diversification, those who settled in Europe had acquired a stroke-suppressor genotype that increases their resistance against atherogenesis, but with protection confined to the intracranial large arteries. The contemporary affluent lifestyle accelerates the development of atherosclerosis. In the whites, it involves the whole arterial bed except the intracranial vessels. People living in non-Western countries used to have a healthier way of living. They did not develop significant atherosclerotic diseases until recently when a westernised lifestyle was adopted. Unlike the whites, their intracranial arteries will not be spared. Atherosclerosis has become a major cause of premature mortality in the modern world, and an anti-atherogenic mechanism would confer a selection advantage. With further adaptive intensification, this protection may extend to the rest of the arterial bed. As a result, future Homo sapiens will be able to tolerate an affluent lifestyle without much adverse sequel such as premature vascular death. Alternatively, if the mediator of this anti-atherogenic mechanism can be identified and applied therapeutically, we will have an ultimate mean to prevent atherosclerosis.

Blood pressure usually considered normal is associated with an elevated risk of cardiovascular disease

PURPOSE

Research on the risk of cardiovascular disease among individuals with prehypertension (blood pressure 120/80 to 139/89 mm Hg) is incomplete. Additional information among individuals with a high risk of cardiovascular disease complications may help to focus current and future efforts.

SUBJECTS AND METHODS

We performed a prospective cohort analysis among 8960 middle-aged adults in the Atherosclerosis Risk in Communities (ARIC) study. The exposure variables were blood pressure levels: high normal blood pressure, systolic blood pressure 130-139 mm Hg or diastolic blood pressure 85-89 mm Hg; and normal blood pressure, systolic blood pressure 120-129 mm Hg or diastolic blood pressure 80-84 mm Hg. The outcome was incident cardiovascular disease defined as fatal/nonfatal coronary heart disease, cardiac procedure, silent myocardial infarction, or ischemic stroke. Subgroup analysis was performed among blacks, diabetics, individuals aged 55-64 years, individuals with renal insufficiency, and among individuals with varying levels of low-density lipoprotein (LDL) cholesterol and body mass index (BMI).

RESULTS

Compared with optimal blood pressure (systolic blood pressure <120 mm Hg and diastolic blood pressure <80 mm Hg), the relative risk (RR) of cardiovascular disease for high normal blood pressure was 2.33 (95% confidence interval [CI], 1.85-2.92), and RR for normal blood pressure was 1.81 (1.47-2.22); among blacks: RR for high normal blood pressure was 3.29 (95% CI, 1.68-6.45); among diabetics: RR for high normal blood pressure 4.10 (95% CI, 2.26-7.46); age 55-64 years: RR for high normal blood pressure 2.41 (95% CI, 1.75-3.30) among individuals with renal insufficiency: RR for high normal blood pressure was 1.90 (95% CI, 1.34-2.70); among individuals with BMI >30 kg/m2: RR for high normal blood pressure was 3.56 (95% CI, 1.99-6.35); and among individuals with LDL >160 mg/dL, RR for high normal blood pressure was 1.85 (95% CI, 1.26-2.72).

CONCLUSIONS

Individuals with prehypertensive levels of blood pressure have an increased risk of developing cardiovascular disease relative to those with optimal levels. The association is pronounced among blacks, among individuals with diabetes mellitus, and among those with high BMI.

Glycaemia (haemoglobin A1c) and incident ischaemic stroke: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Individuals with diabetes have a raised risk of stroke, but it is unclear whether sustained hyperglycaemia contributes to the development of cerebrovascular disease. Haemoglobin A1c (HbA(1c)), a measure of long-term glycaemia, is strongly related to retinopathy, nephropathy, and neuropathy in diabetes. We sought to assess the association between HbA(1c) and stroke in people with and without diabetes.

METHODS

10,886 participants without diabetes and 1635 participants with diabetes in the ARIC study, who did not have cardiovascular disease, were followed up for incident ischaemic stroke over 8-10 years. We assayed HbA(1c) for all 167 stroke cases and a sample of 680 non-cases in the adults without diabetes and for the full cohort of 1635 adults with diabetes (including 89 stroke cases). We assessed the relation between HbA(1c) concentrations (in tertiles specific for individuals with and without diabetes) and incident ischaemic stroke during follow-up using Cox proportional hazards models, controlling for risk factors for stroke.

FINDINGS

The adjusted relative risks of stroke increased with increasing tertile of HbA1c in both adults without diabetes (p=0.02) and with diabetes (p<0.0001). Compared with adults without diabetes in the lowest tertile of HbA1c, the adjusted relative risks of stroke by HbA(1c) tertile were 1.18 (0.70-2.00) and 1.58 (0.94-2.66) in adults without diabetes and 1.75 (0.90-3.42), 2.29 (1.24-4.21), and 4.71 (2.69-8.25) in adults with diabetes.

INTERPRETATION

Raised HbA(1c) could be an independent risk factor for stroke in people with and without diabetes, with relative risks similar to those previously reported for coronary heart disease.

Asymptomatic cerebrovascular disease and systemic diagnosis in stroke, atherothrombosis as a disease of the vascular tree

Atherosclerosis is a chronic vascular disease of true epidemic proportions. It is the first cause of death in developed countries and responsible for one quarter of documented deaths worldwide. Arteriosclerotic vascular disease is a systemic process which affects different organs; principally the heart, brain, and peripheral artery system. Despite well-documented differences, all manifestations of the disease share the same risk factors; albeit with varying degrees of impact. The concept of asymptomatic cerebrovascular disease is an important one for clinicians who treat stroke patients. The development of new neuroimaging and vascular evaluation techniques has enabled the presence of apparently silent lesions to be detected and their progress monitored in follow-up. Ultrasonography techniques enable the identification of atheromatous disease. Asymptomatic involvement of the cerebral parenchyma consists of ischemia, leukoaraiosis, and silent hemorrhage and can be detected using the available radiological techniques such as cranial CT, magnetic resonance, or gradient echo magnetic resonance imaging. From the point of view of prevention, it is of considerable importance to identify diagnostic markers for arteriosclerosis in asymptomatic patients in some, if not all, vascular territories. In view of the natural history of this disease and the impact it has on society, there is an increasing need to identify and understand the risk factors or vascular disease risk markers, so that the stratification of risk of an individual patient or in a specific population can be established, appropriate cerebrovascular assessments conducted, and appropriate therapeutic intervention initiated.

Neuroprotective effects of a postischemic treatment with a bradykinin B2 receptor antagonist in a rat model of temporary focal cerebral ischemia

Bradykinin, an endogenous nonapeptide produced by activation of the kallikrein-kinin system, promotes neuronal tissue damage as well as disturbances in blood-brain barrier function through activation of B2 receptors. In a rat model of focal cerebral ischemia, blockade of B2 receptors before initiation of ischemia with the B2 receptor antagonist, LF 16-0687 Ms, afforded substantial neuroprotection. In order to assess the potential clinical value of this approach, we evaluated the effect of LF 16-0687 Ms given at reperfusion following focal cerebral ischemia on local cerebral blood flow (LCBF), neurological outcome, and infarct size. Sprague-Dawley rats were subjected to MCA occlusion for 90 min by an intraluminal filament. Animals were assigned to one of four treatment arms (n = 7 each): (1) vehicle, (2) LF 16-0687 Ms (1.0 mg/kg/day), (3) LF 16-0687 Ms (3.0 mg/kg/day), or (4) LF 16-0687 Ms (10.0 mg/kg/day) given at reperfusion and repetitively over 2 days. Neurological recovery was examined daily, and infarct volume was assessed histologically on day 7 after ischemia. Physiological parameters and local CBF were not influenced by the treatment. Significant improvement of neurological outcome was observed on postischemic day 3 in animals receiving 1.0 and 3.0 mg/kg/day of LF 16-0687 Ms (P < 0.05). Inhibition of B2 receptors significantly reduced infarct volume in all treated animals predominantly in the cortex. B2 receptor blockade with LF 16-0687 Ms showed neuroprotective effectiveness even when therapy was initiated upon reperfusion, i.e. 90 min after induction of ischemia. Therefore, blockade of B2 receptors seems to be a promising therapeutic approach after focal cerebral ischemia, which deserves further experimental and clinical evaluation.

Diabetes and stroke: Part one—Risk factors and pathophysiology

Diabetes is a major risk factor for stroke and is associated with an increase in overall stroke mortality. The metabolic syndrome associated with insulin resistance is also a significant risk factor for stroke. The etiology of stroke in diabetics is frequently microvascular disease from fibrinoid necrosis, which causes small subcortical infarcts designated as lacunar strokes. Diabetics also have an increased incidence of large vessel intracranial vascular disease. Although strict control of blood sugar has not been shown to reduce the overall incidence of stroke in diabetics, careful management of other associated risk factors, particularly hypercholesterolemia and hypertension, are imperative for the prevention of stroke in diabetic patients.

Association of sleep-disordered breathing and the occurrence of stroke

RATIONALE

Sleep-disordered breathing has been linked to stroke in previous studies. However, these studies either used surrogate markers of sleep-disordered breathing or could not, due to cross-sectional design, address the temporal relationship between sleep-disordered breathing and stroke.

OBJECTIVES

To determine whether sleep-disordered breathing increases the risk for stroke.

METHODS

We performed cross-sectional and longitudinal analyses on 1,475 and 1,189 subjects, respectively, from the general population. Sleep-disordered breathing was defined by the apnea-hypopnea index (frequency of apneas and hypopneas per hour of sleep) obtained by attended polysomnography. The protocol, including polysomnography, risk factors for stroke, and a history of physician-diagnosed stroke, was repeated at 4-yr intervals.

MEASUREMENTS AND MAIN RESULTS

In the cross-sectional analysis, subjects with an apnea-hypopnea index of 20 or greater had increased odds for stroke (odds ratio, 4.33; 95% confidence interval, 1.32-14.24; p = 0.02) compared with those without sleep-disordered breathing (apnea-hypopnea index, <5) after adjustment for known confounding factors. In the prospective analysis, sleep-disordered breathing with an apnea-hypopnea index of 20 or greater was associated with an increased risk of suffering a first-ever stroke over the next 4 yr (unadjusted odds ratio, 4.31; 95% confidence interval, 1.31-14.15; p = 0.02). However, after adjustment for age, sex, and body mass index, the odds ratio was still elevated, but was no longer significant (3.08; 95% confidence interval, 0.74-12.81; p = 0.12).

CONCLUSIONS

These data demonstrate a strong association between moderate to severe sleep-disordered breathing and prevalent stroke, independent of confounding factors. They also provide the first prospective evidence that sleep-disordered breathing precedes stroke and may contribute to the development of stroke.

Stroke subtypes among young patients with systemic lupus erythematosus

PURPOSE

Systemic lupus erythematosus (lupus) is a systemic inflammatory disease associated with premature atherosclerosis, vasculitis, coagulopathy, and excessive incidence of stroke, especially among young patients. Little is known about subtypes of stroke in lupus.

METHODS

A 20% sample of all the hospitalizations in the United States in the years 2001 and 2002 (N approximately 15 million) were analyzed to identify hospitalizations of young patients (age < or =50 years) with systemic lupus erythematosus (n=25704). Proportions of hospitalization for stroke subtypes were compared between the lupus group and the general population group. Age- and sex-adjusted odds ratios for stroke were calculated with logistic regression models.

RESULTS

In the lupus group, there were 313 hospitalizations for stroke of which 206 hospitalizations had stroke as the primary diagnosis. Age- and sex-adjusted stroke risk was higher among the lupus group (odds ratio 1.5, 95% confidence interval 1.3-1.8). Patients with lupus had higher risk for all stroke subtypes except in subarachnoid hemorrhage in which a trend toward a lower risk was observed (odds ratio 0.57, 95% confidence interval 0.34-0.96). Although 12.3% (n=38) of stroke admissions in the lupus group resulted in in-hospital death, this case fatality rate was not statistically different from that for stroke in the general population group.

CONCLUSIONS

Stroke is an important poor outcome in young patients with lupus. Compared with the general population, patients with lupus are more likely to be hospitalized for the risk of ischemic stroke and intracerebral hemorrhage. The risk of subarachnoid hemorrhage, however, seems to be lower in patients with lupus.

Cerebrovascular Diseases as Primary Hospital Discharge Diagnoses: National Trend (1970-2000) Among Older Adults

BACKGROUND

Cerebrovascular diseases are a common cause of mortality, morbidity, and hospitalization among older adults. However, the long-term national trends in cerebrovascular disease-related hospitalizations in this age group are not well known.

METHODS

We used the National Center for Health Statistics trend data from the National Hospital Discharge Surveys (1970-2000) to determine incidence of cerebrovascular disease-related hospitalizations among persons 65 years and older in the United States. Only patients discharged with a primary discharge diagnosis of cerebrovascular disease were included. We estimated rates of hospitalization per 1000 civilian residents 65 years and older, for all patients and stratified by age, sex, and race.

RESULTS

Among persons 65 years of age and older, the total number of cerebrovascular disease-related hospitalizations increased from 372,000 in 1970 to 711,000 in 2000. However, the rates of hospitalization due to cerebrovascular disease remained unchanged at 20.7/1000 in 1970 and 20.4/1000 in 2000. The rates for persons 75-84 years and >85 years were, respectively, 2 and 3 times higher than that for persons 65-74 years throughout the study period. Rates for men and women were comparable and stable during the study period. Rates for African Americans, in contrast, increased from 14/1000 in 1970 to 20.6/1000 in 2000, peaking in 1985 (27.4/1000).

CONCLUSIONS

The overall rates of hospitalization due to cerebrovascular disease remained high yet stable. However, the absolute number of hospitalizations due to cerebrovascular disease increased considerably, with potential for serious social, financial, and public health implications for the coming decades.

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.

Asthma and incident cardiovascular disease: the Atherosclerosis Risk in Communities Study

BACKGROUND

A possible association between asthma and cardiovascular disease has been described in several exploratory studies.

METHODS

The association of self-reported, doctor diagnosed asthma and incident cardiovascular disease was examined in a biracial cohort of 45-64 year old adults (N = 13501) followed over 14 years.

RESULTS

Compared with never having asthma, the multivariate adjusted hazard ratio (HR) of stroke (n = 438) was 1.50 (95% CI 1.04 to 2.15) for a baseline report of ever having asthma (prevalence 5.2%) and 1.55 (95% CI 0.95 to 2.52) for current asthma (prevalence 2.7%). The relative risk of stroke was 1.43 (95% CI 1.03 to 1.98) using a time dependent analysis incorporating follow up reports of asthma. Participants reporting wheeze attacks with shortness of breath also had greater risk for stroke (HR = 1.56, 95% CI 1.18 to 2.06) than participants without these symptoms. The multivariate adjusted relative risk of coronary heart disease (n = 1349) was 0.87 (95% CI 0.66 to 1.14) for ever having asthma, 0.69 (95% CI 0.46 to 1.05) for current asthma at baseline, and 0.88 (95% CI 0.69 to 1.11) using the time dependent analysis.

CONCLUSIONS

Asthma may be an independent risk factor for incident stroke but not coronary heart disease in middle aged adults. This finding warrants replication and may motivate a search for possible mechanisms that link asthma and stroke.

P-selectin Thr715Pro polymorphism predicts P-selectin levels but not risk of incident coronary heart disease or ischemic stroke in a cohort of 14595 participants: the Atherosclerosis Risk in Communities Study

OBJECTIVE

Inflammation, characterized by the recruitment/adhesion of circulating leukocytes by cellular adhesion molecules, plays an important role in the pathogenesis of atherosclerosis. Genetic analyses of P-selectin, a key adhesion molecule in the progression of atherosclerosis, have provided conflicting results regarding the role of variation within the P-selectin gene and risk for heart disease. No studies have examined the association of this polymorphism with stroke. Therefore, we examined the association of the P-selectin Thr715Pro polymorphism with incident coronary heart disease (CHD) and ischemic stroke among 14595 participants in the prospective cohort of the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS AND RESULTS

Incidences of ischemic stroke and CHD were determined through annual telephone calls and hospital and death certificate surveillance. Four hundred fifty-six validated ischemic stroke and 1533 CHD events were identified. P-selectin Pro715 allele frequency was determined in whites and African-Americans, respectively, for CHD cases (0.11, 0.02), CHD non-cases (0.11, 0.02), ischemic stroke cases (0.11, 0.02) and stroke non-cases (0.11, 0.02). The P-selectin Pro715 allele was not associated with risk of CHD or stroke in whites or African-Americans. P-selectin levels, however, were associated with the P-selectin Thr715Pro variant in whites, but not in African-Americans.

CONCLUSIONS

Genotypes carrying the P-selectin Pro715 variant allele are associated with decreased P-selectin levels compared to the homozygous wild-type genotype in whites. The P-selectin Thr715Pro polymorphism is not associated with incident CHD or ischemic stroke in either whites or African-Americans.