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Blood test can predict long-term risk
of death in patients with shortness of breath
BOSTON - February 13, 2006 - Researchers from Massachusetts
General Hospital (MGH) have shown that a blood test previously found
useful for diagnosing heart failure and determining prognosis in
several cardiovascular conditions can also predict the risk of death
among patients coming to hospital emergency departments with shortness
of breath. Their report in the Feb. 14 Archives of Internal Medicine
describes how measuring levels of a protein called NT-proBNP was
the most powerful predictor of whether patients would die within
the year.
"We found that, regardless of whether the patient had been
diagnosed with heart failure, elevated levels of this protein were
strongly prognostic for death at one year and low levels identified
those at the lowest risk," says James Januzzi Jr., MD, of the
MGH
Cardiology Division, the paper's lead author. "Based on
these results, we recommend that every patient coming to a hospital
with shortness of breath be tested for NT-proBNP."
NT-proBNP is a natriuretic peptide, a protein produced when the
cardiac muscle is under stress. In recent years these proteins have
been investigated as assays for various forms of cardiovascular
disease. In April 2005, members of the same MGH research team published
the PRIDE
study, which enrolled almost 600 patients who came to the MGH
Emergency Department with shortness of breath. The PRIDE study showed
that emergency department testing for NT-proBNP could help diagnose
heart failure in those patients, providing a definitive diagnosis
when the result was above specific levels and ruling it out when
results were below an identified point.
The current study, designed to evaluate the long-term prognostic
usefulness of the test, followed up on the patients in the PRIDE
study. The research team contacted primary care physicians or cardiologists
for each of the study participants, or reviewed hospital records,
to determine their status a year after the original emergency visit.
The results, which included data from all but four of the PRIDE
study participants, showed that the NT-proBNP measurement made in
the emergency department was a more accurate predictor of the risk
of death during the following year than were other known measurements
of cardiac risk.
"One of the more impressive findings in our study was the remarkably
strong prognostic ability of NT-proBNP measurement in patients with
shortness of breath from all causes," Januzzi added. "An
elevated NT-proBNP was as strong a predictor of death in patients
without heart failure as it was for those with it. And remarkably,
among those found to have heart failure in the original visit, no
patient with an NT-proBNP level below a certain point died during
the study period.
"Elevations of NT-proBNP can be used not only to determine
the diagnosis and the best hospital setting for treatment but also
to estimate longer-term prognosis, allowing us to identify patients
needing more intensive treatment and follow-up," he adds. "The
next logical step is to evaluate treatment interventions for those
with higher NT-proBNP levels to see if we can reduce their considerable
risk for death." Januzzi is currently directing a randomized
clinical trial of medical therapy guided by NT-proBNP measurement
for patients with recent heart failure.
The study's coauthors are Rahul Sakhuja, MD, MPP, Michelle O'Donoghue,
MD, Aaron Baggish, MD, Saif Anwaruddin, MD, Claudia Chae, MD, MPH,
Renee Cameron, Daniel Krauser, MD, Roderick Tung, MD, and Carlos
Camargo Jr., MD, of MGH, and Donald Lloyd-Jones, MD, ScM, of the
Feinberg School of Medicine at Northwestern University. The study
was supported by a grant from Roche Diagnostics, which manufacturers
the NT-proBNP assay studied but had no role in conducting the investigation
or reporting the results.
Massachusetts General Hospital, established in 1811, is the original
and largest teaching hospital of Harvard Medical School. The MGH
conducts the largest hospital-based research program in the United
States, with an annual research budget of nearly $500 million and
major research centers in AIDS, cardiovascular research, cancer,
cutaneous biology, medical imaging, neurodegenerative disorders,
transplantation biology and photomedicine. In 1994, MGH and Brigham
and Women's Hospital joined to form Partners HealthCare System,
an integrated health care delivery system comprising the two academic
medical centers, specialty and community hospitals, a network of
physician groups, and nonacute and home health services.
Media Contact: Sue
McGreevey, MGH Public Affairs
Physician Referral Service: 1-800-388-4644
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