Ultrasound Escalates Prevalence of Congenital Heart Defects

MONTREAL, Jan. 9 -- There's been a sharp rise in the observed prevalence of congenital heart defects in the past 20 years, according to an analysis of Canadian medical databases.

If the prevalence is roughly the same in the United States as in Canada, some 850,000 Americans may be living with defects that are known, repaired, or still undetected, said Ariane J. Marelli, M.D., of McGill here, and colleagues.

Rather than more babies being born with congenital heart defects, the increase is likely caused by better detection made possible by the development of cardiac ultrasound in the 1980s, the authors said. Moreover, better surgical techniques are allowing patients with congenital heart defects to live longer, they speculated.

In the province of Quebec, the observed prevalence of congenital heart defects rose from 3.57 per 1,000 people in 1985 to 4.09 per 1,000 in the year 2000, Dr. Marelli and colleagues reported in Circulation: Journal of the American Heart Association.

During the same time period, severe congenital heart disease rose in Quebec from 0.21 per 1,000 people to 0.31 per 1,000. In adults, awareness of severe congenital heart disease increased by 85% during the 20 years, while in children awareness of severe congenital heart disease rose by 22%, the researchers reported.

Extrapolating to the general population, these figures indicate that 96,000 patients in Canada and 856,000 patients in the United States were living with congenital heart disease in the year 2000.

More children with the disease appear to be surviving into adulthood, especially those with severe defects, the study found. The majority of patients with severe defects in 1985 were children (65% versus 35% adults). But in 2000, patients with severe disease were divided evenly between adults and children.

In addition, the mean age of patients with severe defects rose from 11 in 1985 to 17 in 2000, the authors said.

Previous reports of congenital defect prevalence have relied on calculations derived from birth prevalence and estimated survival rates. The current study used two national databases, the physicians services and claims database and the hospital discharge summary database, to determine the number of patients in Quebec with congenital defects at five-year intervals during the 15-year study period.

"These data underscore the published estimates and recommendations stating that more specialized care facilities for adults with congenital; heart defects are necessary to meet the needs of this growing population," the authors said.

A clinical perspective from the journal's editors noted that "this study provides important data documenting the growing number of adults with congenital heart disease in the general population. These findings underscore the need for increasing healthcare resource allocation to this emerging population."