Findings from the study were presented here today at the American College of Cardiology 51st Annual Scientific Session.
"This is extremely novel and exciting. There has never been a blood test for congestive heart failure before," said lead investigator Alan Maisel, M.D., director of the Coronary Care Unit at the Veteran Affairs (VA) San Diego Health Care System and professor of medicine at the University of California, San Diego.
The Triage® BNP Test, developed by San Diego-based Biosite, Inc., detects elevated levels in the blood of a hormone called B-type natriuretic peptide (BNP). The hormone is released by the heart ventricles when pressure rises, signaling a failing heart. The test proved effective in a pilot study by Dr.
Maisel two years ago and is already in use in more than 300 hospitals in the United States.
Congestive heart failure (CHF) occurs when the heart can't pump enough blood to supply the rest of the body. A key symptom is shortness of breath. The condition is different from heart attack, where the blood supply to the heart itself is restricted. CHF affects some 4.6 million Americans, with about 40,000 new cases each year. People with CHF can be treated through medication and lifestyle changes, but the five-year survival rate is only about 50 percent.
When patients arrive at the emergency room with shortness of breath, doctors must first determine the cause before they can prescribe effective treatment. Before the BNP test, they had to waitÐsometimes up to hoursÐfor the results of various clinical tests. Dr. Maisel said that with the BNP test, "With two drops of blood you get results in 15 minutes. This test helps saves lives and time."
In the multinational trial, held at seven hospitals in the United States, France and Norway, doctors were able to correctly diagnose CHF in nearly 83 percent of cases, using only the results of the BNP test. When they combined the results with other clinical markers Ðphysical symptoms such as shortness of breath or swollen ankles, or findings from other lab tests Ðthe accuracy rate climbed to 90 percent and above.
The BNP test also has a high "negative predictive value." In the trial, doctors using only the results of the blood test were able to correctly rule out CHF in up to 98 percent of cases, and proceed to diagnosing and treating the real cause of symptoms.
Dr. Maisel published results in the Sept. 15, 2001, American Journal of Cardiology from a study of a different rapid blood test, this one used to diagnose heart attack in the emergency room. That test, also made by Biosite, checks the blood levels of three cardiac enzymes released by distressed heart tissue.
Dr. Maisel and colleagues used the test over nine months on nearly 1,300 patients with signs of heart attack, and were able to achieve a 40-percent drop in critical care admissions, and a 20-percent drop in overall hospital admissions.
The multinational trial of the BNP test was supported by the Department of Veterans Affairs and Biosite, the maker of the BNP test. Dr. Maisel is on the firm's cardiovascular advisory board.
SPECIAL NOTE FOR REPORTERS: Dr. Alan Maisel of the VA San Diego Health Care System is available for press interviews. Please contact Cindy Butler at (858) 552-4373 or cynthia.butler@med.va.gov. For additional assistance, please contact Jim Blue at (212) 807-3424 or james.blue@mail.va.gov.