Heart Defect Seems to Pose Low Risk of Aorta
TUESDAY, Sept. 13 (HealthDay News) -- Many people born with a
heart defect known as bicuspid aortic valve live in fear of sudden
death, but a new study finds only a small risk for a
life-threatening complication called aortic dissection.
However, these people are at high risk of a different
complication -- an aortic aneurysm, or bulge in the wall of the
aorta, researchers report.
Bicuspid aortic valve, the most common congenital heart defect,
occurs when the heart's aortic valve has only two flaps that open
and close rather than the normal three. The aorta, the large blood
vessel that carries blood away from the heart, sometimes tears, or
dissects, as a result of this defect.
"Aortic complications are real in bicuspid aortic valve disease," said lead researcher Dr. Hector I. Michelena, an assistant professor of medicine at the Mayo Clinic in Rochester, Minn.
"The risk of dissection is higher than the general population but remains low," he said. "But both risks of aneurysm and surgery for aneurysm are significantly increased. Despite this, the 25-year survival is not affected in the bicuspid aortic valve disease patient."
This should reassure these patients, Michelena said.
For the study, published in the Sept. 14 issue of the
Journal of the American Medical Association, the researchers examined the medical records of 416 patients diagnosed with bicuspid aortic valve between 1980 and 1999 and looked for complications due to the condition.
Over an average of 16 years' follow-up, two patients had an
aortic dissection, putting the risk at 0.5 percent. Although that
risk is 8.4 times higher than for people without bicuspid aortic
valve, the absolute risk is very low, Michelena's group found.
Forty-nine patients in the study developed aneurysms. That puts
the risk of developing this problem at 26 percent for these
patients, and that's 86 percent higher than the risk for people who
do not have bicuspid aortic valve, the researchers said.
Also, after an aneurysm was found, the risk of aortic surgery
over the next 15 years was 46 percent, and the risk of aortic
dissection was 7 percent. Over 25 years, the risk of having an
operation connected to bicuspid aortic valve was 25 percent, they
Those at the highest risk for an aortic dissection were patients
over 50 and those with aortic aneurysms, Michelena's group noted.
The 25-year risk for needing a valve replacement -- the most common
complication -- was 53 percent, they added.
Dr. Gregg Fonarow, a professor of cardiology at the University
of California, Los Angeles, said that between 1 percent and 2
percent of the population have bicuspid aortic valves. Many
patients have no problems, but some develop blockage or leakage of
the valve and some have abnormalities of the aorta that may result
in aortic dissection. The frequency of this complication has not
been well-studied, Fonarow said.
This study indicates that the absolute risk for this problem is
very low, at three per 10,000 patient years of follow-up, he
"These findings are reassuring and suggest that the rate of aortic dissection among individuals with bicuspid aortic valves, while significantly higher than the general population, are still quite low in absolute terms," Fonarow said.
For more information on bicuspid aortic valves, visit the
U.S. National Library of Medicine.
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