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International multi-center study confirms
value of blood test to diagnose heart failure
Assay powerfully identifies patients'short-term
risk of death
BOSTON - November 17, 2005 - A large-scale international
study has demonstrated the usefulness of a blood test to confirm
or exclude the diagnosis of acute heart failure in emergency room
patients and shows that the test also can identify patients at a
higher risk for death. The report from investigators in the U.S.,
the Netherlands, Spain and New Zealand also clarifies the importance
of age-specific levels of a protein called NT-proBNP that definitively
diagnose heart failure. The report will appear in the European
Heart Journal and is receiving early online release.
"In an analysis of patients from several parts of the world,
we showed that this test is greatly valuable in the diagnosis and
prognosis of patients with both systolic and diastolic heart failure,"
says James Januzzi Jr., MD, of the MGH Cardiology Division, the
paper's co-lead author. "It's a single blood test that can
provide multiple pieces of important information."
Congestive heart failure, which occurs when an impaired heart muscle
cannot pump blood efficiently, is a growing health problem and major
cause of cardiac death. The diagnosis of heart failure may be challenging
because its symptoms can overlap those of other conditions. Earlier
this year Januzzi and colleagues from the MGH published the PRIDE
study, the first prospective American trial measuring NT-proBNP
in patients coming to a hospital emergency department with shortness
of breath. Other research groups, including collaborators in the
current study, have conducted single-site investigations supporting
the usefulness of NT-proBNP for confirming a diagnosis of heart
failure.
The International Collaborative of NT-proBNP (ICON) Study brought
together data from the PRIDE study and similar information from
the Christchurch Cardioendocrine Research Group in New Zealand and
the Hospital de la Santa Creu i Sant Pau in Barcelona, Spain, with
previously unpublished information gathered by researchers from
the University Hospital of Maastricht, The Netherlands, led by co-lead
author Roland van Kimmenade, MD. Their analysis consisted of information
from 1,256 patients, of which 720 had acute heart failure.
As in the earlier studies, NT-proBNP levels were significantly higher
in patients found to have heart failure and highest in those with
the most severe symptoms. The larger scale of the study permitted
more in-depth analysis of data, allowing the establishment of age-specific
NT-proBNP levels defining a clear diagnosis of heart failure. The
measurement below which heart failure could be ruled out was the
same for all age groups.
Analysis of the prospective value of NT-proBNP testing showed that
patients who died within a little more than two months after symptom
onset had significantly higher blood levels of the protein. In fact,
NT-proBNP measurement was the single strongest predictor of death
within that time period, and those with the most significantly elevated
levels had a five-fold increase in the risk of death.
"Because patients with acute heart failure release such high
levels of NT-proBNP, there had been conflicting information about
the usefulness of a single measurement for establishing prognosis,
but this analysis shows the initial assay to be strongly predictive
of short-term outcome," says Januzzi. "Our results underscore
this test's exceptional usefulness for diagnosis and for identifying
those patients who should have higher levels of monitoring and more
aggressive treatment. ICON has set world-wide standards for NT-proBNP
testing in patients coming to hospital emergency departments with
shortness of breath."
An assistant professor of Medicine at Harvard Medical School, Januzzi
adds, "This study was characterized by exceptional collaboration
among these four medical centers. The group from New Zealand pioneered
the use of this test; the researchers from the Netherlands contributed
the largest population of subjects with acute heart failure; and
the clinical investigators from Barcelona previously published one
of the first analyses of NT-proBNP in the emergency department setting.
We are continuing the ICON initiative in several follow-up studies,
two of which have been submitted for publication."
Along with van Kimmenade, co-authors of the ICON study are John
Lainchbury, MD, and Mark Richards, MD, of Christchurch School of
Medicine and Health Sciences in New Zealand; Antoni Bayes-Genis,
MD, Jordi Ordonez-Llanos, MD, PhD, and Miguel Santalo-Bel, MD, Hospital
de la Santa Creu i Sant Pau, Barcelona, Spain; and Yigal Pinto,
MD, University Hospital of Maastricht, The Netherlands. The study
was supported by a grant from Roche Diagnostics, which manufactures
the NT-proBNP assay studied.
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 more than $450 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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