NEW YORK (Reuters Health) – Plasma levels of the cardiac hormone N-terminal pro-B-type natriuretic peptide (NT-proBNP) don’t tell doctors anything about their normal healthy patients, new research shows.

NT-proBNP levels have prognostic value in the general population and in patients with heart failure. But in a study of individuals without any traditional clinical risk factors or echocardiographic abnormalities, any predictive value was “absent,” said lead author Dr. Paul M. McKie and colleagues from the Mayo Clinic, Rochester, Minnesota.

The researchers studied 1991 subjects, age 45 and older, in the community-based Rochester Epidemiology Project. All were free of symptomatic heart failure, but on the basis of echocardiography results the researchers classified 1288 as having stage A/B heart failure. They classified the remaining 703 subjects as healthy normal.

In the May 11th Journal of the American College of Cardiology, the authors report that during a median follow-up of about 9 years, the healthy normal subjects had 19 deaths, 13 heart failure events, 38 strokes, and 14 myocardial infarctions.

However, neither a plasma NT-proBNP above the age- and sex-specific 80th percentile, nor analysis of NT-proBNP as a continuous variable, showed any link with outcome.

On the other hand, the stage A/B Heart failure group had nearly 700 deaths or cardiovascular events, and plasma NT-proBNP was independently associated with events even after adjustment for clinical risk factors and structural/functional cardiac abnormalities. [

Therefore, the researchers conclude, aggressive risk management is called for only when NT-proBNP is elevated in the presence of traditional risk factors or echocardiographic abnormalities, they add.

While “not surprising…this still represents an important finding,” Dr. Jennifer E. Ho and Dr. Daniel Levy from the National Heart, Lung and Blood Institute’s Framingham Heart Study, Massachusetts, write in an editorial. “Identifying persons who would not benefit from a diagnostic test may be just as important as knowing who to test, making this study unique and novel in that regard.”

However, the editorialists note that echocardiography is too expensive for screening the general population, so they ask, “Could natriuretic peptide levels be a useful and cost-effective screening tool in apparently healthy persons, when echocardiography has not already screened out those with structural abnormalities?”

They also point out that the study may be underpowered to detect a moderate difference in outcomes as a function of NT-proBNP, so it may be premature to dismiss its utility for screening the general population.

Reference:

J Am Coll Cardiol 2010;55:2140-2149.