DALLAS, July 2 -- African-Americans are less likely than Caucasians to undergo an important surgery designed to prevent stroke, according to a study published in this month's Stroke: Journal of the American Heart Association.
The study of 803 men hospitalized at four Veterans Affairs hospitals also found that black patients are less likely than whites to receive a diagnostic imaging test that is a crucial first step in determining whether an individual is a candidate for the surgical procedure called carotid endarterectomy.
"We can rule out financial barriers as an explanation for our study's findings because patients in the VA system have equal financial access," says Eugene Oddone, M.D., director of the Center for Health Services Research in Primary Care, VA Medical Center in Durham, N.C., and chief/division of general internal medicine, Duke University Medical Center. Oddone was the lead researcher in the study.
Carotid endarterectomy surgically removes plaque buildup in an artery of the neck that supplies blood to the brain, thereby reducing the likelihood of a stroke. People who have a blockage in the carotid artery are at high risk for stroke as well as for transient ischemic attacks (TIAs), or 'mini-strokes.'
The study examined men 45 years of age and older who were hospitalized for stroke or TIA at one of four VA hospitals between 1991 and 1994. The percentage of blacks and whites in the study was similar, according to Oddone.
"We were trying to answer the question of whether or not African-American patients had equal access to this important surgical procedure," says Oddone. "We found there were clinical differences between the two groups of patients. For example, the black patients on average had a smaller amount of blockage in their carotid artery. However, even after that fact and other clinical factors were taken into account, there were still racial discrepancies. In other words, the clinical factors explained a lot, but they didn't tell us the whole story."
Oddone adds that the clinical differences do not explain why the African-American patients in the study were also less likely to receive carotid ultrasound or carotid angiography -- two important imaging tests to determine whether a patient has substantial plaque obstructions in the carotid artery, making him or her a candidate for carotid endarterectomy. The study found that 67 percent of the blacks in the study received carotid imaging, compared to 79 percent of whites.
Although the study uncovered no concrete explanation for the racial inequity in carotid imaging and carotid endarterectomy, researchers speculate that it may be rooted in the physician-patient relationship. "There may be a racial difference in the way treatment options are communicated to patients by their physician. That may lead to differences in a patient's understanding of what types of treatments are available," explains Oddone. "This may account for previous studies that found that African-Americans tend to be less willing to undergo invasive procedures for preventing stroke."
This latest study also challenges claims of earlier research that found African-Americans generally tend to have more blockages in blood vessels in the brain in addition to the carotid artery, which has been shown to increase the risk of carotid endarterectomy. "This finding fails to support a belief of many physicians that African-Americans tend to have more plaque in their brain arteries. Physicians are generally less likely to recommend patients with blockages in the upper brain for carotid endarterectomy because it is much riskier for those patients," says Oddone.
The study also found that African-American patients were more likely than white patients to have had a stroke (78 percent vs. 55 percent), but less likely to have had a TIA (22 percent vs. 45 percent.)
"Since stroke happens later in the disease process than a TIA, this statistic may point out the need to look at possible racial differences in the evaluation and treatment of cerebrovascular disease prior to hospitalization," says Oddone.
Co-authors are Ronnie D. Homer, Ph.D.; Richard Sloane, M.P.H; Lauren McIntyre, Ph.D.; Aileen Ward, R.N.; Jeff Whittle, M.D., M.P.H; Leigh J. Passman, M.D., Ph.D.; Laura Kroupa, M.D.; Robert Heaney, M.D.; Susan Diem, M.D.; David Matchar, M.D.)