According to a new study, the so-called BNP hormone test is accurate in the short run for predicting whether someone is bound for heart failure within six months.
"There's no question it's here to stay," says Dr. Jerrold Glassman, a cardiologist at Scripps Mercy Hospital in San Diego. "It's a wonderful test."In the past, patients suffering from shortness of breath were very difficult to diagnose.
"If somebody comes in who's a smoker, how do you tell if that belabored breathing is from too much fluid in the heart, or the lungs just acting up?" Glassman says. "In the both cases, the lungs make some noise and the heart is being stressed out, beating faster and harder."
A misdiagnosis could potentially be fatal if a patient goes home without being treated for an underlying heart condition, such as heart failure.
In recent years, however, doctors have been able to turn to a test for the presence of a hormone called B-Type Natriuretic Peptide, or BNP.
The heart secretes the hormone when it stretches to become larger, as it does when it becomes filled with fluid during heart failure.
"It's a pretty sensitive test," says Dr. Eric Eichhorn, a cardiologist and professor of medicine at the University of Texas Southwestern Medical Center. "If you've got heart failure, the BNP value will be elevated. If you have a high BNP, your prognosis is worse."
About 4.7 million people in the United States suffer from congestive heart failure. Despite its name, the condition doesn't mean that the heart has ceased functioning. Instead, it refers to the inability of the heart to pump properly.
An estimated 550,000 new cases of heart failure are diagnosed each year, and the condition kills 250,000 people.
Researchers at San Diego's Veterans Affairs Medical Center and the University of California at San Diego examined 325 patients who sought emergency treatment for shortness of breath.
Fifty-one percent of the patients who had the test and who showed hormone levels four times higher than normal wound up in hospital within six months due to congestive heart failure.
The findings appear in the current issue of the Annals of Emergency Medicine, the journal of the American College of Emergency Physicians. The study was funded in part by BioSite, a company that manufactures the hormone test.
Eichhorn says the test is especially useful because it can be completed quickly, in a matter of minutes. It can also be used to screen people who are at high risk for heart failure.
But, he adds, "you don't want to just give the test to everybody because it's not cost efficient. You want to screen what would be a high-risk population."
Doctors need to be careful to not rely too much on the test, whose results can be affected by factors such as kidney disease, Glassman says. Even so, he says, "It's very cool to have it."