Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, July 6, 1993 TAG: 9307060076
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: Associated Press
DATELINE: ATHENS, GA. LENGTH: Medium
How this living human tissue reacts finally could tell if the cell structure of black men and women makes them more susceptible than whites to heart disease.
"We think the common denominator is the blood vessel itself," said Dr. Randall Tackett of the University of Georgia, who is conducting the study. "But no one has really looked at blood vessels . . . to explain the difference between black and white patients."
Heart disease is the nation's No. 1 killer, causing about half a million deaths each year. Black men have a 39 percent higher rate of death from cardiovascular disease than white men. The risk is even higher for black women - 68 percent more than white women.
Blacks die of heart disease much faster than whites. Even minor hardening of the arteries can be fatal, and blacks are more prone to debilitating high blood pressure.
Doctors don't know why. In women, they think hormones certainly play a role. And they suspect some of the difference results from higher poverty rates among black Americans.
But those theories are based only on surveys of people's habits and medical records, and most of that research was done primarily on white males. Experts say Tackett is the first to search for a physical cause for heart disease's racial disparity.
"Knowing at the cellular level or at the vascular level if there are in fact differences - that would be very important," said Dr. Richard Pratt, a professor at Stanford University.
It's extremely difficult to find living human tissue, much less experiment with it, Pratt said. Among the few scientists who have done so are Stanford researchers trying to determine why heart bypasses often reclog.
To compare blacks' and whites' blood vessels, Tackett takes tissue from heart-bypass operations at the Medical College of Georgia.
Surgeons use the saphenous vein from the leg and the mammary artery from the chest to bypass clogged coronary arteries. They almost always have pieces left over.
So whenever the medical college schedules a bypass, graduate student Dustan Barber makes the two-hour drive to Augusta. He waits in the operating room for the leftover tissue, packs it in a cooler and races back to Athens.
The medical college does about 250 bypasses a year, half on black patients. Tackett expects to compare tissue from about 600 patients, black and white, in the next three years.
He's not sure what to expect. Black patients' blood vessels may be more sensitive to stress. They may need different concentrations of medicines to fend off heart disease. They may lack the chemicals needed to break down free radicals, the destructive molecules that float through people's bodies.
"It's amazing how much we don't know," Tackett said.
Tackett's theory that physical, not cultural or societal, differences make blacks more susceptible to this killer is very plausible, said Dr. Allen Naftilan of Vanderbilt University.
Blacks have different antigens in their blood than whites. And other diseases, from cancers to sickle cell anemia, attack some races and nationalities more than others.
But he warned that Tackett's research was just a beginning.
"All blacks are not genetically the same. If he finds a difference, people will have to do careful family studies" to determine who's most at risk, Naftilan said. "But you've got to start someplace."
If Tackett's work shows there is a physical cause for the disparity, he wants to examine even smaller blood vessels to see where the defect starts.
"If we know what's occurring in the blood vessels, we may be able to prevent cardiovascular deaths in some people," he said. "It's the one option that's never been addressed."
by CNB