TUESDAY, Sept. 16 (HealthDay News) -- Young adults with a congenital heart defect called a bicuspid aortic valve don't have lower survival rates than those in the general population, say Canadian researchers.

A bicuspid aortic valve has only two flaps (cusps) that open and close, instead of the normal three. It's the most common congenital heart defect in the adult population. Prior studies have reported significant death and illness associated with the defect.

The researchers examined cardiac outcomes and disease progression in 642 patients, average age 35. Over an average period of nine years, 161 of the patients (25 percent) in this study had one or more primary cardiac events: cardiac-related death, 17 patients; intervention on the aortic valve or ascending aorta (first section of the aorta), 142 patients; aortic tearing or aneurysm, 11 patients; or congestive heart failure requiring hospitalization, 16 patients.

Independent predictors of primary cardiac events included: being older than age 30; moderate or severe aortic narrowing; and moderate or severe aortic regurgitation (flow of blood back into the heart).

The cardiac death rate was 0.3 percent per patient-year of follow-up, a death rate not significantly different from that of the general population, the researchers said. The five- and 10-year survival rates for those in the bicuspid aortic valve group were 97 percent and 96 percent, compared with 97 percent and 97 percent in the general population.

The findings were published in the Sept. 17 issue of the Journal of the American Medical Association.

"Outcome differences between present and prior studies can be attributed to differences in the era that patients were examined, the population that was examined, the frequency of cardiac events associated with high mortality (aortic [tearing] and endocarditis [inflammation of the endocardium and heart valves]), and advances in perioperative management," wrote the University of Toronto and University of Western Ontario researchers.

"Young adults with bicuspid aortic valve have a high likelihood of eventually requiring interventions on the aortic valve and/or aorta and will need serial surveillance of aortic valve and aortic dimensions," they concluded.

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Related MedlinePlus Pages:

• Congenital Heart Defects
• Heart Valve Diseases