Coronary arteriographic findings in black patients and risk markers for coronary artery disease

Prognostic Impact of Race in Patients Undergoing PCI: Analysis From 10 Randomized Coronary Stent Trials

OBJECTIVES

The aim of this study was to assess race-based differences in patients undergoing percutaneous coronary intervention from a large pooled database of randomized controlled trials.

BACKGROUND

Data on race-based outcomes after percutaneous coronary intervention are limited, deriving mainly from registries and single-center studies.

METHODS

Baseline characteristics and outcomes at 30 days, 1 year, and 5 years were assessed across different races, from an individual patient data pooled analysis from 10 randomized trials. Endpoints of interest included death, myocardial infarction, and major adverse cardiac events (defined as cardiac death, myocardial infarction, or ischemia-driven target lesion revascularization). Multivariate Cox proportional hazards regression was performed to assess associations between race and outcomes, controlling for differences in 12 baseline covariates.

RESULTS

Among 22,638 patients, 20,585 (90.9%) were white, 918 (4.1%) were black, 404 (1.8%) were Asian, and 473 (2.1%) were Hispanic. Baseline and angiographic characteristics differed among groups. Five-year major adverse cardiac event rates were 18.8% in white patients (reference group), compared with 23.9% in black patients (p = 0.0009), 11.2% in Asian patients (p = 0.0007), and 21.5% in Hispanic patients (p = 0.07). Multivariate analysis demonstrated an independent association between black race and 5-year risk for major adverse cardiac events (hazard ratio: 1.28; 95% confidence interval: 1.05 to 1.57; p = 0.01).

CONCLUSIONS

In the present large-scale individual patient data pooled analysis, comorbidities were significantly more frequent in minority-group patients than in white patients enrolled in coronary stent randomized controlled trials. After accounting for these differences, black race was an independent predictor of worse outcomes, whereas Hispanic ethnicity and Asian race were not. Further research examining race-based outcomes after percutaneous coronary intervention is warranted to understand these differences.

Black-white differences in severity of coronary artery disease among individuals with acute coronary syndromes

OBJECTIVE

To determine whether the extent of coronary obstructive disease is similar among black and white patients with acute coronary syndromes.

DESIGN

Retrospective chart review.

PATIENTS

We used administrative discharge data to identify white and black male patients, 30 years of age or older, who were discharged between October 1, 1989 and September 30, 1995 from 1 of 6 Department of Veterans Affairs (VA) hospitals with a primary diagnosis of acute myocardial infarction (AMI) or unstable angina (UnA) and who underwent coronary angiography during the admission. We excluded patients if they did not meet standard clinical criteria for AMI or UnA or if they had had prior percutaneous transluminal coronary angioplasty or coronary artery bypass grafting.

MEASUREMENTS AND MAIN RESULTS

Physician reviewers classified the degree of coronary obstruction from blinded coronary angiography reports. Obstruction was considered significant if there was at least 50% obstruction of the left main coronary artery, or if there was 70% obstruction in 1 of the 3 major epicardial vessels or their main branches. Of the 628 eligible patients, 300 (48%) had AMI. Among patients with AMI, blacks were more likely than whites to have no significant coronary obstructions (28/145, or 19%, vs 10/155 or 7%, P =.001). Similarly, among patients with UnA, 33% (56/168) of blacks but just 17% (27/160) of whites had no significant stenoses (P =.012). There were no racial differences in severity of coronary disease among veterans with at least 1 significant obstruction. Racial differences in coronary obstructions remained after correcting for coronary disease risk factors and characteristics of the AMI.

CONCLUSIONS

Black veterans who present with acute coronary insufficiency are less likely than whites to have significant coronary obstruction. Current understanding of coronary disease does not provide an explanation for these differences.

Transforming growth factor-beta 1 hyperexpression in African American end-stage renal disease patients

End-stage renal disease (ESRD) is more frequent in African Americans (blacks) compared to Caucasian Americans (whites). Identification of remediable causes of the increased prevalence has the potential to reduce the excess burden of ESRD. Because renal fibrosis is a correlate of progressive renal failure and a dominant feature of ESRD, and because transforming growth factor-beta 1 (TGF-beta 1) can induce fibrosis and renal insufficiency, we explored the hypothesis that TGF-beta 1 hyperexpression is more frequent in black ESRD patients compared to white ESRD patients. Our postulate was tested by determining circulating levels of TGF-beta 1 protein in the sera of 56 black and 42 white ESRD patients treated by chronic hemodialysis. A solid-phase sandwich enzyme-linked immunosorbent assay, specific for TGF-beta 1, was used to quantify TGF-beta 1 levels in the ESRD cohort. Additional cytokines implicated in tissue repair/remodeling, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), were also measured. Our investigation demonstrated a significantly higher concentration of TGF-beta 1 protein but not that of IL-6 or TNF-alpha in blacks compared to whites. Our observation that TGF-beta 1 is hyperexpressed in black ESRD patients suggests a mechanism for the increased prevalence of renal failure (since TGF-beta 1 hyperexpression can result in renal insufficiency in experimental models) among the black population.

Clinical and angiographic findings in black patients with suspected coronary artery disease

To determine the clinical variables and coronary angiographic findings in black patients with suspected coronary artery disease, we analyzed the data on consecutive black patients undergoing their first coronary angiogram over a three year period at the Cook County Hospital, Chicago, Illinois. We compared these findings to those of black and white patients from previous studies. There were 654 patients with a mean age+/-standard deviation of 56+/-10 years; 309 (47%) were men. Two hundred nineteen patients (33%) presented with unstable angina, 75 patients (12%) with acute myocardial infarction and 338 patients (52%) with chronic stable angina. Three hundred forty-six patients (53%) had 50% or greater stenosis in at least one of the major vessels. Among the patients with coronary artery disease, 128 patients (37%) had one vessel disease, 102 patients (29%) had two-vessel disease, and 116 patients (34%) had three-vessel disease. Black patients who undergo coronary angiography for suspected coronary artery disease have a high frequency of normal coronary angiogram or non-obstructive coronary artery disease. The frequency of 1-, 2- and 3-vessel disease in blacks with coronary artery disease is comparable to those observed in whites in previous reports.

Body mass index and coronary artery disease in African-Americans

There are limited data available concerning the influence of obesity, a major cardiovascular disease risk factor, in relationship to coronary artery disease (CAD). This is of considerable importance to African-Americans since African-Americans have one of the world's highest CAD mortality rates coupled with the fact that obesity is extremely prevalent in this population. The present study assessed the relationship between body mass index and CAD in African-Americans undergoing coronary angiography. Eight hundred sixty-six available cardiac catheterization reports between the years 1983 through 1990 were retrospectively reviewed at Howard University Hospital in Washington, D.C. CAD was prevalent in 59.6% and 41.2%, males and females, respectively. Among the males overweight and obesity were found in 22.4% and 20.9%, respectively, compared to 39.6% and 30.6% for females. An upside-down U-shaped relationship between BMI and CAD was found. The interpretation of this finding is that being overweight is associated with increased risk of CAD compared to the lean and obese.