Severity of coronary artery disease among blacks with acute myocardial infarction

The effect of ethnicity on the relationship between premature coronary artery disease and traditional cardiac risk factors among uninsured young adults

Prior studies of premature coronary artery disease (CAD) in young adults did not address the association of race/ethnicity and risk factors. Therefore, the authors conducted a study of 400 patients 40 years and older undergoing coronary angiography at a large, urban public hospital that serves predominantly minority, uninsured populations. The prevalence of risk factors and their association with premature CAD varied markedly by ethnic group. Among blacks, dyslipidemia, diabetes, and smoking were independently associated with premature CAD. Among Hispanics, dyslipidemia, male sex, and family history of CAD were independently associated with premature CAD. Smoking was the only risk factor in whites, and no independent risk factor was identified in Asian Indians. Whites and Asian Indians had a higher prevalence of disease than blacks or Hispanics--before and after adjusting for risk factor imbalances across ethnic groups. In this ethnically diverse population, the authors' findings underscore the importance of identifying distinctive risk factors in various ethnic groups.

African Americans and Caucasians have a similar prevalence of coronary calcium in the Dallas Heart Study

OBJECTIVES

We sought to compare the prevalence of coronary atherosclerosis in a cohort of middle-age African American (black) and non-Hispanic Caucasian (white) men and women from a population-based probability sample.

BACKGROUND

Blacks have a higher mortality from coronary heart disease (CHD) than whites, particularly among younger individuals, and yet several studies have reported that coronary atherosclerosis is less prevalent in blacks than in whites. Data from population-based samples comparing coronary atherosclerotic burden between blacks and whites are limited.

METHODS

The prevalence of coronary atherosclerosis in middle-aged blacks and whites was determined using coronary calcium measured by electron beam computed tomography in 1,289 men and women from a population-based probability sample from Dallas, Texas.

RESULTS

The population estimates of the frequency of a positive scan for coronary artery calcium were not statistically different between black and white men (37% vs. 41%, p = 0.36) or between black and white women (29% vs. 23%, p = 0.21). Although the prevalence of most of the coronary risk factors varied significantly between blacks and whites, mean Framingham coronary risk factor scores were identical in black and white men (10 +/- 4) but significantly higher in black women (13 +/- 4) than in white women (12 +/- 4).

CONCLUSIONS

Blacks in the general population have a prevalence of coronary atherosclerosis similar to whites. Factors other than coronary atherosclerotic burden, which are not reflected in the Framingham risk score, contribute significantly to the higher CHD mortality rate in blacks.

Traditional risk factors and the incidence of sudden coronary death with and without coronary thrombosis in blacks

BACKGROUND

Blacks have a high rate of sudden coronary death (SCD). We determined the rate of SCD in men and women 30 to 69 years of age in a 6-year period recorded at a state Medical Examiner's Office.

METHODS AND RESULTS

In a subset of 327 whites and 130 blacks, hearts were systematically studied to determine the extent of coronary disease, presence and type of thrombus (acute rupture, acute erosion, stable plaque), and heart weight. These parameters were correlated with the presence of conventional risk factors. The estimated rate of SCD in blacks was similar to that in whites under the age of 40 years but increased compared with whites with advancing age, becoming 1.5 times the rate for whites in the 7th decade (95% of the increase in the 6th decade was due to sudden death with stable plaque). Among the autopsied group with severe coronary atherosclerosis, HDL cholesterol was higher and hypertension more prevalent in blacks, but there was no difference in the prevalence of healed infarcts, plaque burden, heart weight, acute thrombi, or rates of diabetes, cigarette smoking, and total cholesterol.

CONCLUSIONS

When compared with a control autopsy group of 568 deaths, multivariate analysis showed a significant association in blacks between stable plaque and left ventricular hypertrophy (risk ratio, 7.6), type 1 diabetes (risk ratio, 3.6), hypertension (risk ratio, 3.5), elevated total cholesterol (risk ratio, 3.1) and type 2 diabetes (risk ratio, 2.9). Because these risk factors are associated with SCD in blacks, they may be important targets for reducing the disparately high rate of SCD in blacks as compared with whites.

Racial differences in the prevalence of left ventricular hypertrophy among chronic cocaine abusers

There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy in hypertension. This study was performed to determine whether racial differences also exist in LV hypertrophy among chronic cocaine users. We studied 112 chronic cocaine abusers < 45 years old in whom normal blood pressures (< or = 140/90 mm Hg) were recorded 3 times daily for 3 weeks. LV wall thickness and mass were measured echocardiographically. Technically adequate studies were obtained in 79 blacks and 33 whites. Self-reported cocaine use was higher in whites than in blacks (688 +/- 516 vs 431 +/- 468 $/week, p = 0.03). There were no group differences in terms of duration of cocaine use, age, height, weight, blood pressure, LV dimensions, or left atrial size. However, posterior wall thickness (1.13 +/- 0.17 vs 1.03 +/- 0.14 cm, p = 0.0035) and LV mass index (113 +/- 25 vs 94 +/- 19 g/m2, p = 0.0001) were significantly greater in blacks. LV hypertrophy, defined as an M-mode LV mass index > or = 134 g/m2, was present in 24 blacks (30%) and 2 whites (6%) (p = 0.011). When defined as a posterior wall thickness > or = 1.2 cm and a 2-dimensional echocardiographic LV mass index > or = 105 g/m2, LV hypertrophy was present in 37 of 79 blacks (47%) and in 6 of 33 whites (18%) (p = 0.0086). Cocaine-related LV hypertrophy is more prevalent in black men than in white men.(ABSTRACT TRUNCATED AT 250 WORDS)

Atherogenesis and thrombosis: mechanisms, pathogenesis, and therapeutic implications

Although the mortality rate from coronary heart disease (CHD) has declined by almost 50% during the past 25 years, CHD remains the leading cause of death in the United States and is responsible for more than 500,000 deaths annually. The underlying cause of CHD is coronary atherosclerosis. Although the intact intima is highly resistant to thrombus formation, when injury occurs, even superficial, a sequence of reactions is initiated--platelet aggregation, macrophage accumulation, intimal smooth muscle proliferation, fibrous tissue proliferation, and lipid accumulation--that result in the development of obstructive atheroma. Repeat intimal injury and cycling of this process lead to continued progression of the atheroma and coronary artery occlusion. Unstable angina and acute myocardial infarction appear to result from rupture of an atherosclerotic plaque, hemorrhage into the plaque, and luminal thrombosis. The cause of plaque rupture is unknown and may result from normal hemodynamic forces when the fibrous cap of an atheroma has become severely attenuated and fragile. Based on the pathogenesis of chronic atherosclerosis and acute rapid atheroma progression, several therapeutic options become evident. These include antiplatelet, anticoagulant, and thrombolytic therapies, as well as the possibility of arrest and reversal of atherosclerosis in some patients.

Congestive heart failure, coronary events and atherothrombotic brain infarction in elderly blacks and whites with systemic hypertension and with and without echocardiographic and electrocardiographic evidence of left ventricular hypertrophy

Hypertension was present in 50% of 196 blacks and in 36% of 382 whites (p less than 0.001). A prospective study of 84 elderly blacks (70% women) and 326 elderly whites (73% women) with hypertension correlated echocardiographic and electrocardiographic left ventricular (LV) hypertrophy with incidences of congestive heart failure (CHF), coronary events and atherothrombotic brain infarction (ABI). Echocardiographic LV hypertrophy (p less than 0.02) and concentric LV hypertrophy (p less than 0.001) were more prevalent in hypertensive blacks than in hypertensive whites. Hypertensive blacks were younger (78 +/- 9 years) than hypertensive whites (82 +/- 7 years) (p less than 0.001). Other coronary risk factors were similar, except for higher serum triglycerides in whites than in blacks (p less than 0.02). Follow-up was 37 +/- 18 months in blacks and 43 +/- 18 months in whites (p less than 0.01). Incidences of CHF and coronary events were not significantly different in blacks and whites. ABI incidence was 38% in blacks and 21% in whites (p less than 0.005). Multiple logistic regression analysis showed that prior CHF (p = 0.000), concentric LV hypertrophy (p = 0.018) and echocardiographic LV hypertrophy (p = 0.022) were independent risk factors for CHF. Echocardiographic LV hypertrophy (p = 0.001), serum total cholesterol (p = 0.002), concentric LV hypertrophy (p = 0.005) and prior coronary artery disease (p = 0.042) were independent risk factors for coronary events. Prior ABI (p = 0.001), echocardiographic LV hypertrophy (p = 0.001) and electrocardiographic LV hypertrophy (p = 0.034) were independent risk factors for ABI.