The ethnic-specific nature of mechanisms for coronary heart disease

Vascular calcification: pathophysiology and risk factors

Vascular calcification can occur in nearly all arterial beds and in both the medial and intimal layers. The initiating factors and clinical consequences depend on the underlying disease state and location of the calcification. The best studied manifestation is coronary artery calcification, in part because of the obvious clinical consequences, but also because of CT-based imaging modalities. In the general population, the presence of coronary artery calcification increases cardiovascular risk above that predicted by traditional Framingham risk factors, suggesting the presence of nontraditional risk factors. In patients with chronic kidney disease (CKD), coronary artery calcification is more prevalent and markedly more severe than in the general population. In these CKD patients, nontraditional risk factors such as oxidative stress, advanced glycation end products, and disordered mineral metabolism are also more prevalent and more severe and offer mechanistic insight into the pathogenesis of vascular calcification.

Ethnicity/race, use of pharmacotherapy, scope of physician-ordered cholesterol screening, and provision of diet/nutrition or exercise counseling during US office-based visits by patients with hyperlipidemia

BACKGROUND

Elevation of serum cholesterol, or hyperlipidemia, is recognized as one of the major modifiable risk factors in the development of atherosclerosis and cardiovascular disease. On a US population basis, there has been a downward trend in total- and LDL-cholesterol levels, and an increase in cholesterol screening. Nevertheless, previous research suggests that there remain racial/ethnic disparities in the access to and quality of care for hyperlipidemia.

OBJECTIVE

The aim of this study was to examine the extent of racial/ethnic disparities in the provision of pharmacotherapy, cholesterol screening and diet/nutrition or exercise counseling during US office-based physician-patient encounters (visits) by patients with hyperlipidemia.

METHODS

We examined data from the 2005 US National Ambulatory Medical Care Survey for office-based visits for hyperlipidemia for patients aged > or =20 years in terms of prescribing for hyperlipidemia, and the ordering/provision of cholesterol testing, diet/nutrition counseling, and exercise counseling.

RESULTS

Use of pharmacotherapy for hyperlipidemia varied by ethnicity/race (chi2, p < 0.05). Physician-ordered/provided cholesterol screening occurred in 44.2% of all office-based visits; 46.5% for Whites, 35.4% for Blacks, and 30.3% for Hispanics (chi2, p < 0.05). Diet/nutrition counseling was ordered/provided in 39.7% of office-based visits; 40.4% for Whites, 32.6% for Blacks, and 39.0% for Hispanics (chi2, p < 0.05). Exercise counseling was ordered/provided in 32.1% of office-based visits; 32.7% for Whites, 27.2% for Blacks, and 30.6% for Hispanics (chi2, p < 0.05).

CONCLUSIONS

These findings reveal a disparity in use of pharmacotherapy for hyperlipidemia, physician-ordered/provided cholesterol screening, diet/nutrition counseling, and exercise counseling by ethnicity/race. Further research is required to discern, in greater detail, reasons for the observed differences reported, and to ensure equitable access to established standards of care.

Ethnicity and diabetic heart disease

Ethnicity is a complex yet important construct and an independent risk factor for diabetic heart disease (DHD) with paramount clinical significance. Clinicians should try to better understand the role of ethnicity through more questions. The risk of DHD is modified by ethnicity through more questions. The risk of DHD is modified by ethnicity, and its management may require a culturally sensitive individualized approach. Findings from Caucasian populations cannot be fully extrapolated to other ethnic groups, thereby emphasizing the importance of future research with ethnicity-based threshold for obesity. Available limited data support the interaction between genetic predisposition, environmental risk, and lifestyle choices and disparities based on ethnicity as the likely cause for ethnic variations in DHD.

Racial differences in the association of coronary calcified plaque with left ventricular hypertrophy: the National Heart, Lung, and Blood Institute Family Heart Study and Hypertension Genetic Epidemiology Network

Studies have reported a lower burden of calcified atherosclerotic plaque in coronary arteries in African-Americans than in whites. Findings from autopsy studies of sudden cardiac death have suggested a link between left ventricular hypertrophy and severity of coronary atherosclerosis. Echocardiograms and cardiac computed tomograms were analyzed in 334 African-American (84% hypertensive) and 196 white (66% hypertensive) adults with no history of coronary heart disease or revascularization procedures at study entry. The relation of coronary artery calcium (CAC) score to left ventricular mass and left ventricular mass indexed to body surface area was assessed by Spearman's correlations and mixed linear models. Covariates included age, gender, field center, weight, height, systolic blood pressure, number of antihypertensive medications, diabetes, total and high-density lipoprotein cholesterol levels, and current smoking and alcohol consumption. In African-Americans, a significant and independent association between CAC score and left ventricular mass or left ventricular mass indexed to body surface area was present with the 2 analytic strategies. Spearman's correlation coefficients for CAC score with left ventricular mass and left ventricular mass indexed to body surface area were 0.14 (p = 0.015) and 0.13 (p = 0.025), respectively, after multivariable adjustment. In whites, the associations of CAC score with measurements of left ventricular mass were weaker and only marginally significant in mixed linear models. In conclusion, these findings suggest that CAC reflects a different risk burden between African-Americans and whites, and future studies examining the prognostic implications of CAC in African-Americans should consider the potential association between CAC and left ventricular hypertrophy.

Genes, diet and serum lipid concentrations: lessons from ethnically diverse populations and their relevance to coronary heart disease in Asia

PURPOSE OF REVIEW

The burden of coronary heart disease (CHD) in Asia has risen in tandem with socio-economic development and urbanization. Although all ethnic groups have been affected, some appear to be at particularly high risk. The basis of these ethnic differences remains poorly understood.

RECENT FINDINGS

Differing levels of risk factors for CHD have been observed between ethnic groups. Previous studies, however, may be confounded by a large ethnic variation in socio-economic status and place of residence. Few studies have taken dietary factors into account. Recent studies involving Chinese, Malays and Asian Indians living in Singapore suggest that neither dietary nor genetic factors, taken in isolation, sufficiently explain ethnic differences in serum lipid profiles. Several genetic variants in key candidate genes (apolipoprotein E, APOE, cholesteryl ester transfer protein, CETP and hepatic lipase, LIPC) have recently been found to modulate the association between dietary factors and serum lipid concentrations in these ethnic groups and in other populations.

SUMMARY

To fully evaluate the differences in CHD risk between ethnic groups, environmental exposures, including dietary factors need to be carefully evaluated, and gene-environment interactions that may give rise to these differences need to be taken into account. These are critical steps in the development of targeted strategies to contain the epidemic of coronary heart disease in Asia. An understanding of the basis of these differences may also provide insights into the pathogenesis of disease that one cannot get through the examination of more homogenous populations.

Ethnic differences in the presentation, treatment strategy, and outcomes of percutaneous coronary intervention (a report from the National Heart, Lung, and Blood Institute Dynamic Registry)

Information about the impact of race/ethnicity on adverse outcomes after percutaneous coronary intervention (PCI) in the modern era is limited. Using consecutive patients from the National Heart, Lung, and Blood Institute Dynamic Registry, this study investigated differences in clinical presentation, treatment strategy, and acute and long-term outcomes in 3,669 white, 446 black, 301 Hispanic, and 201 Asian patients who underwent PCI. All comparisons were made to whites. Blacks were more likely than whites to be younger, women, and to present with a higher prevalence of cardiovascular risk factors (hypertension, diabetes, and smoking). Hispanics tended to be younger, hypertensive, diabetic, and to be undergoing their first cardiovascular procedure. Asians were, on average, younger, men, and presented more often with hypertension and diabetes than whites. Although the rate of stent implantation was significantly lower in blacks compared with whites (63% vs 74%, p <0.001), angiographic and procedural success rates were high (> or =95%) and did not differ by race/ethnicity. In-hospital mortality (0.2% vs 1.7%, p <0.05) and death/myocardial infarction (MI)/coronary artery bypass grafting (CABG) (3.1% vs 5.5%, p <0.05) were lower in blacks. All other in-hospital complications were similar to whites. At 1 year, there were no statistical differences in cumulative adverse event rates by ethnicity; however by 2 years there was a modestly higher mortality rate (adjusted RR 1.87; 95% confidence interval 1.15 to 3.04) and adverse event rate (death/MI, death/MI/CABG) among black patients. Thus, although differences in patient demographics, clinical presentation, angiographic characteristics and treatment strategies did not impact the incidence of acute and 1-year adverse outcomes of non-whites, there appears to be a significant reduction in event-free survival among blacks by 2 years.