Ethnic differences in arterial responses, inflammation, and metabolic profiles: possible insights into ethnic differences in cardiovascular disease and stroke

Influence of ethnic background on left atrial markers of inflammation, endothelial function and tissue remodelling

BACKGROUND

It has been suggested that ethnicity can make a significant difference to the likelihood of thromboembolic stroke related to atrial fibrillation. Ethnic differences have been shown to alter inflammatory and haemostatic factors; however, this may all be confounded by differences in cardiovascular risk factors between different ethnicity. The impact of different ethnicities on the thrombogenic profile is not known. The aim of this study was to investigate differences in markers of inflammation, endothelial function and tissue remodelling between Caucasian and Indian populations with supraventricular tachycardia (SVT).

METHODS

Patients with structurally normal hearts undergoing catheter ablation for SVT were studied. This study included 23 Australian (Caucasian) patients from the Royal Adelaide Hospital, Adelaide, Australia and 24 Indian (Indian) patients from the Christian Medical College, Vellore, India. Blood samples were collected from the femoral vein, and right and left atria. Blood samples were analysed for the markers of endothelial function (ADMA, ET-1), inflammation (CD40L, VCAM-1, ICAM-1), and tissue remodelling (MMP-9, TIMP-1) using ELISA.

RESULTS

The study populations were well matched for cardiovascular risk factors and the absence of structural heart disease. No difference in the echocardiographic measurements between the two ethnicities was found. In this context, there was no difference in markers of inflammation, endothelial function or tissue remodelling between the two SVT populations.

CONCLUSION

Caucasian and Indian populations demonstrate similar inflammatory, endothelial function or tissue remodelling profiles. This study suggests a lack of an impact of different ethnicity in these populations in terms of thrombogenic risk.

Association between carotid intima-media thickness and aortic arch plaques

BACKGROUND

Large aortic arch plaques are associated with ischemic stroke. Carotid intima-media thickness (CIMT) is a marker of subclinical atherosclerosis and a strong predictor of cardiovascular disease and stroke. The association between CIMT and aortic arch plaques has been studied in patients with strokes, but not in the general population. The aim of this study was to investigate this association in an elderly asymptomatic cohort and to assess the possibility of using CIMT to predict the presence or absence of large aortic arch plaques.

METHODS

Stroke-free control subjects from the Aortic Plaque and Risk of Ischemic Stroke (APRIS) study underwent transesophageal echocardiography and high-resolution B-mode ultrasound of the carotid arteries. CIMT was measured at the common carotid artery, bifurcation, and internal carotid artery. The association between CIMT and aortic arch plaques was analyzed using multivariate regression models. The positive and negative predictive values of CIMT for large (>or=4 mm) aortic arch plaques were calculated.

RESULTS

Among 138 subjects, large aortic arch plaques were present in 35 (25.4%). Only CIMT at the bifurcation was associated with large aortic arch plaques after adjustment for atherosclerotic risk factors (P=.007). The positive and negative predictive values of CIMT for aortic arch plaque>or=4 mm at the bifurcation above the 75th percentile (>or=0.95 mm) were 42% and 80%, respectively. The negative predictive value increased to 87% when the median CIMT value (0.82 mm) was used.

CONCLUSIONS

CIMT at the bifurcation is independently associated with aortic arch plaque>or=4 mm. Its strong negative predictive value for large plaques indicates that CIMT may be used as an initial screening test to exclude severe arch atherosclerosis in the general population.

Arterial stiffness indices in healthy volunteers using non-invasive digital photoplethysmography

BACKGROUND

Increased arterial stiffness is a marker of cardiovascular damage, even in the absence of clinically apparent disease. It is likely to become an important clinical tool in cardiovascular risk assessment.

AIMS AND METHODS

We studied a group of healthy subjects and measured their arterial stiffness by digital photoplethysmography. We aimed to obtain a range of arterial stiffness values, and investigated the influence of age, gender, race, body mass index, fasting lipids and haemodynamic factors.

RESULTS

One hundred and fifty-two healthy subjects, aged between 18 and 67 years, on no medications and with no significant medical illnesses were recruited. The population was predominantly Caucasian (n = 112). Two measures of arterial stiffness were obtained: stiffness index (SI), a measure of large arterial stiffness, and reflection index (RI), a measure of small to medium-sized arterial stiffness. SI and RI were significantly correlated with age, total cholesterol, low-density lipoprotein-cholesterol, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP). Race was a significant independent predictor of SI.

CONCLUSION

Digital photoplethysmography is a portable, operator-independent, reproducible and simple method of measuring arterial stiffness. Ranges of normality of arterial stiffness will depend on the individual's age, race, lipid levels, HR and blood pressure.

What do we know about adherence and self-care?

Despite advances in healthcare, heart failure patients continue to experience complications that could have been prevented or treated. This occurs because the only way that a therapeutic or preventive regimen can be effective, assuming that the patient's condition has been accurately diagnosed and appropriately treated, is if the patient implements self-care behaviors and adheres to the treatment regimen. However, it is widely accepted that this does not occur in many or even most instances. This article provides an overview of the current evidence related to adherence and self-care behaviors among heart failure patients and describes the state of the science on interventions developed and tested to enhance self-care maintenance in this population. Our review of literature shows that effective interventions integrate strategies that motivate, empower, and encourage patients to make informed decisions and assume responsibility for self-care. Gaps in current evidence support the need for additional research on ways to improve adherence and self-care for patients who are at an increased risk of poor adherence, including those with cognitive and functional impairments and low health literacy.

The vascular effects of metabolic impairment clusters in subjects of different ethnicities

BACKGROUND

Although metabolic syndrome affects vascular function, the impact of individual impairments and their clustering is unclear.

OBJECTIVE

To assess the vascular impact of metabolic impairments before they reach treatment thresholds in different ethnic groups.

METHODS

Metabolic variables, inflammatory markers, endothelium dependent vasodilatation (EDV) and carotid intima media thickness (CIMT) were measured in population samples of 82 Caucasians and 78 matched Afro-Caribbeans with no vascular disease. Insulin resistance was assessed using homeostasis model assessment (HOMA-IR). EDV was measured as the change in the height of the inflection point of the digital volume pulse following intravenous infusion of 5 mcg/min of albuterol (DeltaRIDeltaLB). Regression models were used to investigate the independent effects of metabolic impairment clusters and their interaction with ethnicity on EDV and CIMT.

RESULTS

HOMA-IR (2.4-3.8, p < 0.0001), IL-6 levels (1.1-2.8 pg/mL, p = 0.02) and CIMT (0.71-0.83 mm, p = 0.009) increased whereas in DeltaRIBASELINE (77.6-72.9 percentage points, p < 0.0001) and DeltaRIDeltaLB (15.5-7.1 percentage points, p < 0.0001) decreased with the number of metabolic impairments present. DeltaRIDeltaLB decreased by 1.6 (95% CI 0.2-3.7) percentage points and CIMT increased by 0.06 (95% CI 0.02-0.10) mm for each metabolic impairment present after adjusting for age, gender, ethnicity and HOMA-IR. There were significant interactions between Afro-Caribbean ethnicity and metabolic impairments for IL-6 (p = 0.037) and DeltaRIDeltaLB (p = 0.002).

CONCLUSIONS

Clustering of metabolic impairments is associated with inflammatory activation, impaired EDV and increased CIMT even before reaching treatment thresholds for individual impairments. This effect was more marked in Afro-Caribbean subjects.