Blood Test Predicts Death Risk In Patients With Shortness of Breath
MONDAY, Feb. 13 (HealthDay News) -- A blood test doctors have long used to diagnose heart failure can also predict long-term risk of death in patients with shortness of breath, researchers report.
Levels of a protein called NT-proBNP gauge whether patients are likely to die within a year of being seen in the emergency department complaining of difficulties in breathing.
Based on the finding, the researchers believe patients with shortness of breath should routinely have the test and undergo aggressive therapy if their levels are found to be high.
"NT-proBNP has become a very important tool in the diagnosis of heart failure among patients who present with shortness of breath," said study co-author Dr. Donald Lloyd-Jones, an assistant professor of medicine at the Feinberg School of Medicine at Northwestern University. "This paper adds just how powerful a marker NT-proBNP can be in determining a patient's prognosis."
The report appears in the Feb. 13 issue of the Archives of Internal Medicine.
"NT-proBNP is released from the heart in response to stress on the heart," explained study author Dr. James Januzzi Jr., an assistant professor of medicine at Harvard Medical School and a staff cardiologist at Massachusetts General Hospital.
In addition to heart failure, NT-proBNP levels can be elevated in heart attack, unstable angina, pulmonary embolism and acute high blood pressure.
In their study, the researchers took blood samples to determine the levels of NT-proBNP of 599 patients treated in the emergency department for shortness of breath. Patient outcomes were then tracked for one year.
Ninety-one patients died by the one-year mark. Blood levels of NT-proBNP were significantly higher among those who died compared with patients who were still alive, the researchers found.
"NT-proBNP levels predicted the risk of death at one year, regardless of whether [the death risk] was elevated because you had heart failure, or whether you had some other reason for it to be elevated," Lloyd-Jones said.
Lloyd-Jones believes that all patients who have shortness of breath should have their levels of NT-proBNP assessed.
"This marker is well established in clinical practice for diagnosis and for long-term prognosis," he said. "It needs to be used to guide us to understand the cause of shortness of breath, and also to make sure that we are appropriately intensive in our diagnostic workup and our therapy."
Whether lowering NT-proBNP levels will improve outcome is an open question that Januzzi said his team hopes to answer.
In an ongoing study, the Boston group is identifying patients with high NT-proBNP for aggressive therapy. "We are looking at the level of NT-proBNP to assess the success of treatment, and whether their treatment is making a difference in the levels of NT-proBNP," Januzzi said. "We know that you can drive the level of NT-proBNP down. But the million-dollar question is can you improve outcomes by doing that?"
Another expert said it's not clear whether routine NT-proBNP testing will result in different or better treatment for patients.
"What is interesting is that the NT-proBNP level, which is thought to convey information about heart failure, predicted outcome in patients with and without heart failure," said Dr Harlan M. Krumholz, a professor of cardiology at Yale University School of Medicine. "The question remains whether this information would have changed any diagnosis or caused the modification of any treatment strategy."
"Before recommending that this test be performed routinely for every patient in the emergency department, as the authors do, it would be prudent to study whether the information provided by this test can lead to interventions that will improve patient outcomes," Krumholz said.
"More information can be good -- but only if it can ultimately help patients," he added.
For more on heart disease risk, head to the American Heart Association.