Race Differences in High-Grade Carotid Artery Stenosis

Background and Purpose

Despite a higher incidence of stroke and a more adverse cardiovascular risk factor profile in Blacks and Hispanics compared with Whites, carotid artery revascularization is performed less frequently among these subpopulations. We assessed racial differences in high-grade (≥70% diameter-reducing) carotid stenosis.

Methods

Consecutive clients in a Nationwide Life Line for-Profit Service to screen for vascular disease, 2005 to 2019 were evaluated in a cross-sectional study. The prevalence of high-grade stenosis, defined by a carotid ultrasound peak systolic velocity of ≥230 cm/s, was assessed. Participants self-identified as White, Black, Hispanic, Asian, Native American, or other. Race/ethnic differences were assessed using Poisson regression. The number of individuals in the United States with high-grade stenosis was estimated by applying prevalence estimates to 2015 US Census population estimates.

Results

The prevalence of high-grade carotid stenosis was estimated in 6 130 481 individuals. The prevalence of high-grade stenosis was higher with increasing age in all race-sex strata. Generally, Blacks and Hispanics had a lower prevalence of high-grade stenosis compared with Whites, while Native Americans had a higher prevalence. For example, for men aged 55 to 65, the relative risk of stenosis compared with Whites was 0.40 (95% CI, 0.29–0.55) and 0.61 (95% CI, 0.46–0.81) for Blacks and Hispanics, respectively; and 1.53 (95% CI, 1.12–2.10) for Native Americans. When these prevalence estimates were applied to the Census estimates of the US population, an estimated 327 721 individuals have high-grade stenosis, of whom 7% are Black, 7% Hispanic, and 43% women.

Conclusions

Despite their having a more adverse cardiovascular risk profile, there was a lower prevalence of high-grade carotid artery stenosis for both the Black and Hispanic relative to the White clients. This lower prevalence of high-grade stenosis is a potential contributor to the lower use of carotid revascularization procedures in these minority populations.

Using Ultrasound and Inflammation to Improve Prediction of Ischemic Stroke: A Secondary Analysis of the Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

Current ischemic stroke risk prediction is primarily based on clinical factors, rather than imaging or laboratory markers. We examined the relationship between baseline ultrasound and inflammation measurements and subsequent primary ischemic stroke risk.

METHODS

In this secondary analysis of the Multi-Ethnic Study of Atherosclerosis (MESA), the primary outcome is the incident ischemic stroke during follow-up. The predictor variables are 9 carotid ultrasound-derived measurements and 6 serum inflammation measurements from the baseline study visit. We fit Cox regression models to the outcome of ischemic stroke. The baseline model included patient age, hypertension, diabetes, total cholesterol, smoking, and systolic blood pressure. Goodness-of-fit statistics were assessed to compare the baseline model to a model with ultrasound and inflammation predictor variables that remained significant when added to the baseline model.

RESULTS

We included 5,918 participants. The primary outcome of ischemic stroke was seen in 105 patients with a mean follow-up time of 7.7 years. In the Cox models, we found that carotid distensibility (CD), carotid stenosis (CS), and serum interleukin-6 (IL-6) were associated with incident stroke. Adding tertiles of CD, IL-6, and categories of CS to a baseline model that included traditional clinical vascular risk factors resulted in a better model fit than traditional risk factors alone as indicated by goodness-of-fit statistics.

CONCLUSIONS

In a multiethnic cohort of patients without cerebrovascular disease at baseline, we found that CD, CS, and IL-6 helped predict the occurrence of primary ischemic stroke. Future research could evaluate if these basic ultrasound and serum measurements have implications for primary prevention efforts or clinical trial inclusion criteria.

Carotid artery plaque morphology and composition in relation to incident cardiovascular events: the Multi-Ethnic Study of Atherosclerosis (MESA)

PURPOSE

To determine if carotid plaque morphology and composition with magnetic resonance (MR) imaging can be used to identify asymptomatic subjects at risk for cardiovascular events.

MATERIALS AND METHODS

Institutional review boards at each site approved the study, and all sites were Health Insurance Portability and Accountability Act (HIPAA) compliant. A total of 946 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) were evaluated with MR imaging and ultrasonography (US). MR imaging was used to define carotid plaque composition and remodeling index (wall area divided by the sum of wall area and lumen area), while US was used to assess carotid wall thickness. Incident cardiovascular events, including myocardial infarction, resuscitated cardiac arrest, angina, stroke, and death, were ascertained for an average of 5.5 years. Multivariable Cox proportional hazards models, C statistics, and net reclassification improvement (NRI) for event prediction were determined.

RESULTS

Cardiovascular events occurred in 59 (6%) of participants. Carotid IMT as well as MR imaging remodeling index, lipid core, and calcium in the internal carotid artery were significant predictors of events in univariate analysis (P < .001 for all). For traditional risk factors, the C statistic for event prediction was 0.696. For MR imaging remodeling index and lipid core, the C statistic was 0.734 and the NRI was 7.4% and 15.8% for participants with and those without cardiovascular events, respectively (P = .02). The NRI for US IMT in addition to traditional risk factors was not significant.

CONCLUSION

The identification of vulnerable plaque characteristics with MR imaging aids in cardiovascular disease prediction and improves the reclassification of baseline cardiovascular risk.

Extracranial carotid plaque is increasing in Japanese ischemic stroke patients

OBJECTIVE

The objectives of this study were to investigate the prevalence of extracranial carotid plaque and the association between risk factors and carotid plaque in Japanese patients with ischemic stroke.

METHODS

We consecutively recruited patients with ischemic stroke admitted to our hospital from January 2000 to September 2002. Neurologic signs and a brain magnetic resonance imaging diagnosed ischemic stroke. All subjects underwent a carotid ultrasonography. Multiple logistic regression analysis was used to determine the risk factors that independently contributed to the presence of carotid plaques.

RESULTS

Carotid plaques were identified in 76.2% of the patients and bilateral plaques were found in 58.2%. These lesions were more frequent in comparison with previous Japanese reports. The risk factors that independently contributed to the presence of extracranial carotid plaques were hypertension, age, smoking and past history of ischemic stroke.

CONCLUSIONS

This study demonstrates that extracranial carotid plaque is increasing in Japanese patients with ischemic stroke.

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.

Increased carotid intima-media thickness in remote and urban Indigenous Australians: impact of diabetes and components of the metabolic syndrome

OBJECTIVE

Indigenous Australians have rates of cardiovascular (CVD) mortality some seven to 10-fold higher than non-Indigenous Australians aged 25-64 years. We aimed to evaluate the impact of type 2 diabetes and components of the metabolic syndrome on carotid intima-media thickness (CIMT) as a marker of cardiovascular risk in Indigenous Australians living in remote and urban environments and in Australians of European ancestry.

DESIGN, PATIENTS AND MEASUREMENTS

CIMT was measured by high-resolution B-mode ultrasound imaging of the common carotid artery in 119 remote Indigenous, 144 urban Indigenous and 122 urban European Australians with and without diabetes.

RESULTS

In nondiabetic participants, CIMT was lowest in Europeans (mean (SD) 0.64 mm (0.10)), higher in urban Indigenous Australians (0.67 mm (0.12)) and highest in remote Indigenous Australians (0.73 mm (0.15), P < 0.001). CIMT was higher with diabetes with the same pattern observed between populations: 0.73 mm, 0.79 mm and 0.82 mm, respectively (P < 0.001). Traditional risk factors (age, male gender, blood pressure and HbA1c) explained 35-45% of the variance of CIMT within each population group. However, differences in CIMT between population groups were maintained after adjustment for these cardiovascular risks plus cholesterol and smoking (P < 0.001). Factor analysis revealed that variables of the metabolic syndrome, together with smoking and elevated C-reactive protein (CRP) and urinary albumin-creatinine ratio (ACR), are likely to explain the higher CIMT in Indigenous Australians (and the urban-remote gradient). Unmeasured variables (genetic, psychosocial and socioeconomic) may also contribute to higher CIMT in these populations.

CONCLUSION

Glycaemic control and metabolic syndrome components contribute significantly to premature atherogenesis in Indigenous Australians and we recommend that therapy should be targeted accordingly.

Detection of carotid stenosis in African Americans with ischemic heart disease

OBJECTIVES

This study was conducted to define the frequency of internal carotid stenosis in African American patients with ischemic heart disease (IHD).

METHODS

We recruited 101 African American patients with IHD from a university medical center for carotid duplex examination.

RESULTS

The frequency of >30%, >50%, and >70% stenosis was 21%, 11%, and 5%, respectively. Age >60 years (21% vs 3%, P < .01) and diabetes mellitus (22% vs 5%, P < .01) were predictors of unilateral stenosis of >50% and remained significant on multivariate testing.

CONCLUSION

African American patients with established IHD have higher rates of extracranial carotid stenosis than community dwelling African American subjects and comparable rates with other populations.

The impact of ethnicity and sex on subclinical cardiovascular disease: the Diabetes Heart Study

AIMS/HYPOTHESIS

African-Americans with type 2 diabetes and access to adequate healthcare are at lower risk of clinical coronary artery disease than are white diabetic patients. We evaluated whether ethnic differences in subclinical cardiovascular disease, coronary and carotid artery calcified plaque and carotid artery intima-medial thickness (IMT) were present in members of The Diabetes Heart Study families.

SUBJECTS AND METHODS

In a bi-racial cohort of 1,180 individuals from families enriched for members with type 2 diabetes, we calculated coronary and carotid artery calcified plaque using fast-gated helical computed tomography, and measured carotid artery IMT and clinical risk factor profiles. Generalised estimating equations were used to test for an association between measures of subclinical cardiovascular disease and ethnicity and sex.

RESULTS

After adjustment for age, ethnicity and kidney function, African-Americans had significantly lower amounts of coronary artery calcified plaque (mean+/-SE) (866+/-158 vs 1,915+/-135, respectively; p=0.0466) and carotid artery calcified plaque (179+/-51 vs 355+/-27, respectively; p=0.0240) relative to whites, despite having increased carotid IMT (0.71+/-0.01 vs 0.67+/-0.004 cm, respectively; p=0.0007), and higher blood pressure, albuminuria and HbA1c. Sex-specific analyses revealed that African-American men had significantly lower coronary and carotid artery calcified atheroma than white men. In women, ethnic differences in calcified carotid artery plaque, but not coronary artery plaque, were observed.

CONCLUSIONS/INTERPRETATION

In families enriched for members with type 2 diabetes, African-American men had markedly lower levels of coronary and carotid artery calcified plaque than white men, despite increased carotid artery IMT and conventional risk factors. These findings suggest that susceptibility to subclinical cardiovascular disease differs markedly according to ethnicity and sex.

Carotid endarterectomy in older women and men in the United States: trends in ethnic disparities

Trends in utilization of carotid endarterectomy (CEA) among elderly ethnic minorities have received little attention. Data from the U.S. Centers for Medicare and Medicaid Services were examined for the years 1990 through 2000. In women and men, the rate of CEA per 100,000 non-HMO beneficiaries aged > or = 65 years increased in African Americans and in European Americans between 1990 and 1995, with only small changes thereafter. Between 1990 and 2000, the ratio of rates in European Americans to those in African Americans have decreased slightly, i.e., in women from 2.63 in 1990 to 2.24 (15%) in 2000 and in men from 3.94 to 3.39 (14%). Large ethnic differences in utilization of CEA persist in the elderly requiring further evaluation.

Prevalence of carotid artery stenosis in Taiwanese patients with one ischemic stroke

PURPOSE

Ethnic differences in the distribution of atherosclerosis in the brain-supplying vessels are well described. However, only scarce data exist on the prevalence of extracranial carotid artery stenosis in Taiwanese patients who have had a single ischemic stroke.

METHODS

Color-coded duplex sonography was used to evaluate the carotid arteries in a hospital-based study on 276 consecutive first-time Taiwanese stroke patients. Significant atherosclerotic lesions of the internal carotid arteries (ICA) were defined as a stenosis of more than 50% or an occlusion.

RESULTS

The prevalence of significant carotid lesions was 6% (35/552) in the entire cohort and 8% (17/224) in patients with hemispheric strokes. Among patients with large-artery atheroscleroses, according to criteria of the Trial of Org 10172 in Acute Stroke Treatment, only 27% had significant extracranial ICA disease whereas 69% had intracranial vessel stenoses. Older patients tended to have more severe ICA lesions, while other risk factors were not correlated with carotid stenosis.

CONCLUSION

The prevalence of more than 50% ICA stenosis was low in Taiwanese patients with first hemispheric ischemic strokes, indicating that it is not a major cause of ischemic stroke in this population.

Outcome of carotid endarterectomy in African Americans: is race a factor?

OBJECTIVE

African American patients have been underrepresented in large-scale trials of carotid endarterectomy (CEA). Thus the role of CEA in the treatment of extracranial carotid artery occlusive disease in black patients remains unclear. We undertook this study to determine the effect of black race on early and late outcome of CEA.

METHODS

A retrospective review was performed of records for patients who underwent CEA from 1990 to 1999. Data on demographics, operative indications, hospital course, and long-term follow-up were obtained for each patient. Patients were stratified by race for comparison of perioperative course and late outcome. Risk factors were compared using chi(2) methods, and life table analysis was performed with Kaplan-Meier survival plots.

RESULTS

One thousand forty-five CEA procedures were performed during the study period, 133 (13%) in black patients and 912 (87%) in white patients. Demographic risk factors were similar in both groups, except for hypertension (P =.003), diabetes (P <.001), and renal insufficiency (P =.03), which were more prevalent in blacks. Just over half of patients had symptoms at presentation, with equal racial distribution. The perioperative stroke and death rate was 3.3% (blacks, 5.3%; whites, 3.1%; P =.19). The 8-year actuarial ipsilateral stroke rate was 7% in patients without symptoms and 8% in patients with symptoms, with no racial variation. There was, however, a racial difference in the long-term "all strokes" rate (P =.002), regardless of vascular territory. This difference was largely due to the high late stroke rate in black patients with symptoms at presentation. A Cox proportional hazards analysis showed that only black race was a significant predictor of any stroke.

CONCLUSIONS

CEA can be accomplished with acceptable morbidity and mortality in black patients with an expectation of similar protection from ipsilateral ischemic stroke as in white patients. Black patients, however, have a higher incidence of all strokes at long-term follow-up due to the higher risk of stroke in patients with symptoms of carotid bifurcation disease.

Effects of the ultrasound contrast-enhancing agent Levovist on the detection of intracranial arteries and stenoses in chinese by transcranial Doppler ultrasound

Proper assessment of intracranial arteries by transcranial Doppler sonography (TCD) in patients with intracranial stenoses is occasionally made difficult by an insufficient temporal bone window, an unfavourable insonation angle, or low flow velocity or volume. This condition is frequently found in Chinese. In these cases, echocontrast could be helpful. We investigated 48 temporal windows of 24 acute Chinese stroke patients with insufficient native transtemporal insonation conditions before and after the application of the echo enhancer Levovist (galactose/palmitic acid) by an injection pump. We classified the signal quality from four segments of the main intracranial arteries: anterior cerebral artery (A1), main stem of the middle cerebral artery (MCA, M1), intracranial segment of the carotid artery (C1), and posterior cerebral artery (P1). The signal quality was classified as follows: 0 = no signal, 1 = poor, envelope curve does not follow spectrum, 2 = adequate, envelope curve follows spectrum. As compared to the pre-contrast scans, echocontrast allowed for more segments to be evaluated by pulsed Doppler sonography. Before Levovist, only 12% of the segments could be detected, after Levovist 63%. For all arteries, signal quality was better after Levovist, p between 0.0180 and 0.0003. In 3 patients, MCA stenoses with peak systolic Doppler flow velocities above 160 cm/s were found only after Levovist. In patients with poor pre-contrast detection, echocontrast-enhanced TCD allows for more arterial segments to be insonated and for the detection of stenoses unnoted during the non-enhanced investigation.

Pattern of atherosclerotic carotid stenosis in Korean patients with stroke: different involvement of intracranial versus extracranial vessels

BACKGROUND AND PURPOSE

The clinical pattern of stroke and the angiographic distribution of cerebral atherosclerosis in the Japanese and Chinese are different from those in whites. Our purpose was to evaluate the location and distribution of severe atherosclerotic stenoses in Korean patients by using cerebral angiography.

METHODS

We retrospectively reviewed the cerebral angiographic findings in 268 patients (219 male, 49 female; mean age, 56 years) with one or more severe atherosclerotic stenoses (> or =70%), as shown on angiograms. These patients were selected from 1436 patients who were examined between 1996 and 1997. The analysis focused on the intracranial or extracranial location of the stenosis, the anterior and posterior circulations, and the multiplicity of the lesions. Statistical analysis was performed by using the chi(2) test. The data were then compared with data reported in other races and ethnic groups.

RESULTS

A total of 389 severe stenotic sites were detected in 268 patients. A single stenosis was found in 56 (21%), and multiple stenoses were found in 212 (79%). Lesions were located in the intracranial area in 52% and in the extracranial area in 48%. They were detected in anterior circulation in 59% and in posterior circulation in 41%. Thirty-seven (66%) of 56 single stenosis were located in the intracranial area, and 19 (34%) were in the extracranial area. Of 333 lesions, 167 (50%) were multiple stenoses in the extracranial area, and 166 lesions (50%) were located in the intracranial vessels. The prevalence of intracranial stenosis was significantly higher in the single-stenosis group than in the multiple stenosis group (P <.05).

CONCLUSION

Korean patients with severe atherosclerotic stenoses tend to have more intracranial stenoses. In particular, those with an isolated stenosis have more intracranial stenoses, compared with those with multiple stenoses.

Genetic basis of variation in carotid artery plaque in the San Antonio Family Heart Study

BACKGROUND AND PURPOSE

In contrast to the commonly used quantitative marker of subclinical atherosclerosis, namely intima-media thickness, we investigated the extent to which the presence or absence of carotid artery plaque (CAP) was under genetic control.

METHODS

The study population consisted of 750 individuals distributed across 29 randomly ascertained extended Mexican American pedigrees who participated in the second examination cycle of the San Antonio Family Heart Study. Extracranial focal CAP was identified by B-mode ultrasound bilaterally in the internal carotid artery or the carotid bulb. Using a variance decomposition approach implemented in the SOLAR computer program, we performed genetic analysis on the discrete trait CAP (ie, liability to disease) using a threshold model. Covariates considered in the analysis included age, sex, diabetes, current smoking status, lipid levels, and markers of hypertension and obesity.

RESULTS

Fifty-one of 461 women and fifty-seven of 289 men with a mean age of 42.1 years had evidence of a plaque in the right and/or left carotid artery. The age- and sex-adjusted heritability (h(2)+/-SE) for CAP was significant (h(2)=0.28+/-0.15, P=0.01). Furthermore, after adjustment for additional covariates that contributed significantly to the model (P<0.05; diabetes, hypertension, body mass index, waist circumference, and smoking status), heritability remained significant (h(2)=0.23+/-0.15, P=0.03).

CONCLUSIONS

Our data indicate that after established cardiovascular risk factors are controlled for, the variation of the discrete trait CAP is under appreciable additive genetic influences.

Carotid intima-media thickness is associated with allelic variants of stromelysin-1, interleukin-6, and hepatic lipase genes: the Northern Manhattan Prospective Cohort Study

BACKGROUND AND PURPOSE

Atherosclerosis is a complex disorder with hereditary and environmental causes. Carotid artery intima-media wall thickness (IMT) is a useful measure of atherosclerosis. The objective of this study was to determine the association between carotid IMT and functional promoter variants of stromelysin-1 (MMP3: -1612 5A>6A), interleukin-6 (IL6: -174G>C), and hepatic lipase (HL: -480C>T) genes.

METHODS

B-mode carotid ultrasound was performed among 87 subjects (mean age, 70+/-12 years; 55% women; 60% Caribbean-Hispanic, 25% black, and 13% white) from the Northern Manhattan Prospective Cohort Study. Carotid IMT was calculated as a composite measure (mean of the maximum IMT in the bifurcation, the common carotid artery, and the internal carotid artery).

RESULTS

For all polymorphisms, genotype distribution was not significantly different from Hardy-Weinberg equilibrium. The frequencies of the rare alleles were as follows: MMP3 -1612 5A>6A, 0.31 (95% CI, 0.25 to 0.39); IL6 -174 G>C, 0.20 (95% CI, 0.13 to 0.25); and HL -480 C>T, 0.45 (95% CI, 0.35 to 0.50). Carotid IMT in the sample was 0.78+/-0.18 mm. Subjects with the MMP3 genotype 6A6A had 8% greater mean carotid IMT than the other MMP3 genotypes combined (0.95+/-0.17 versus 0.87+/-0.15 mm; P=0.04). Subjects with the IL6 genotype GG had 11% greater IMT (0.85+/-0.17 versus 0.76+/-0.16 mm; P=0.03), and those with the HL genotype CC had 13% greater IMT (0.87+/-20 versus 0.76+/-0.18 mm; P=0.02) than the other genotypes combined. Adjustment for other risk factors did not change these associations.

CONCLUSIONS

Carotid IMT is higher among subjects homozygous for functional variants in genes related to matrix deposition (MMP3 -16126A), inflammation (IL6 -174G), and lipid metabolism (HL -480C). These associations were independent of race-ethnicity and some environmental exposures. Further studies are needed to confirm these genotype-phenotype associations.

Mechanisms of retinal arterial occlusive disease in African American and Caucasian patients

BACKGROUND AND PURPOSE

The aim of our study was to evaluate the causes of retinal arterial occlusive disease in African American patients and to compare these etiologies with those observed in Caucasian patients with retinal ischemic symptoms.

METHODS

We performed a retrospective analysis of a series of consecutive patients evaluated by both the ophthalmology department and the neurology/stroke clinic. Patients had a diagnosis of amaurosis fugax, branch retinal artery occlusion, central retinal artery occlusion, or intra-arterial retinal plaques.

RESULTS

Twenty-nine African American patients and 17 Caucasian patients were evaluated. African American patients had a mean age of 61 years (range, 30 to 77 years) and Caucasian patients a mean age of 73 years (range, 56 to 94 years) (P=0.003). There was no statistically significant difference between the 2 groups with respect to visible emboli on funduscopy (P=0.462). After adjusting for age, there was also no difference between the 2 groups with regards to risk factors for arterial occlusive disease such as hypertension, coronary artery disease, hypercholesterolemia, tobacco use, and history of stroke or transient ischemic attacks. Caucasian patients had a 41% incidence (7/17) of high-grade ipsilateral internal carotid artery stenosis, measured by carotid duplex, compared with 3.4% incidence (1/29) in African American patients (P=0.002).

CONCLUSIONS

There are racial differences in the causes of retinal arterial occlusion. African American patients have a low prevalence of moderate to severe extracranial carotid stenosis, and a high proportion of African American patients have cryptogenic retinal ischemia. In Caucasian patients there is a stronger association between extracranial carotid artery disease and retinal arterial occlusion.

Cigarette smoking as a determinant of high-grade carotid artery stenosis in Hispanic, black, and white patients with stroke or transient ischemic attack

BACKGROUND AND PURPOSE

We sought to investigate the association of cigarette smoking with high-grade carotid artery stenosis in Hispanic, black, and white patients with cerebral ischemia in two independent samples.

METHODS

Prospectively collected data from the Northern Manhattan Stroke Study (NOMASS) (n=431) and the Berlin Cerebral Ischemia Databank (BCID) (n=483) were used separately for a cross-sectional study estimating the association between cigarette smoking and high-grade carotid stenosis (defined as a luminal narrowing of > or =60%, diagnosed by duplex and/or Doppler ultrasound). In both studies, cerebral ischemia patients with normal sonographic findings or nonstenosing plaques of their carotid arteries served as a comparison group. Multivariate logistic regression models were used for statistical tests to determine the association between smoking and the dependent variable for high-grade carotid stenosis. Age, sex, hypertension, diabetes, hypercholesterolemia, and race/ethnicity were considered potential confounders. Further analyses of the NOMASS data estimated the effect of the amount of cigarette use and the impact of race/ethnicity.

RESULTS

High-grade carotid stenoses were found in 14% of the NOMASS and in 21% of the Berlin patients. In Berlin the entire sample was white, whereas in New York only 19% of the cohort were white. In both samples, smoking was independently associated with severe carotid stenosis (NOMASS: odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1 to 2.0; BCID: OR, 3.9; 95% CI, 2.4 to 6.4). Patients smoking 20 pack-years or more showed a significant association (OR, 2.0; 95% CI, 1.1 to 3.9), whereas no significant effect was found for lower amounts of cigarette use. In NOMASS, white smokers displayed a significant (OR, 3.2; 95% CI, 1.1 to 8.9) association with high-grade carotid stenosis, the association for black smokers was less strong, and no association was found among Hispanics.

CONCLUSIONS

Smoking is an independent determinant of severe carotid artery stenosis in patients with focal cerebral ischemia. The association differs by race/ethnicity, with the greatest effect observed among whites.

Vascular lesions in Chinese patients with transient ischemic attacks

We studied 96 Chinese patients with TIAs using transcranial Doppler and duplex ultrasonography. We found intracranial stenosis or occlusion in 51% of cases and extracranial disease in 19% of cases. The most common intracranial lesion was stenosis of the terminal internal carotid artery or proximal middle cerebral artery, whereas the most common extracranial lesion was stenosis of the carotid bifurcation.

Carotid plaque associations among hypertensive patients

OBJECTIVE

To assess the relationship between cardiovascular risk factors and carotid plaque.

DESIGN

Hypertensive patients were screened for randomization into the Multicenter Isradipine Diuretic Atherosclerosis Study, a trial intended to determine if blood pressure control by isradipine as compared with hydrochlorothiazide will blunt the progression of carotid plaque (intima plus media thickness, 1.3 to 3.5 mm) in patients with serum cholesterol levels of less than 6.85 mmol/L (265 mg/dL) without insulin-dependent diabetes mellitus or estrogen therapy. Demographics of those who underwent B-mode ultrasound evaluations at common, bifurcation, and internal carotid artery sites to detect plaque were assessed from a southern and a northern site.

SETTING

Participants were from ambulatory outpatient clinics associated with medical schools.

PATIENTS

The initial screening included 1823 hypertensive volunteer patients who were between 40 and 83 years of age who had a diastolic pressure of 90 to 114 mm Hg (or < 90 mm Hg with treatment).

OUTCOME MEASURES

Complete data were collected on the variables of age, cholesterol, cigarette smoking, race, gender, and the presence of carotid plaque in 1126 patients.

RESULTS

All variables were significantly associated with carotid plaque (intima plus media thickness, > or = 1.3 mm). The adjusted percentage with plaque was 66.4% +/- 3.4% for blacks and 70.1% +/- 2.3% for whites at the southern site and 42.7% +/- 4.5% for blacks and 61.3% +/- 3.2% for whites at the northern site. The rate of plaque was 75.8% among cigarette smokers, despite a mildly elevated cholesterol level.

CONCLUSIONS

Although these 1126 cases do not constitute a random sample of patients, these data suggest that there may be regional differences in racial tendencies toward plaque among blacks.