No Increase in Deaths or Hospitalizations for Heart
Failure Patients Who Have a Pulmonary Artery Catheter
New Orleans, LA, Nov. 9, 2004 – The pulmonary
artery catheter (PAC), a device that measures pressures and flows
in the heart, is frequently used to diagnose, monitor, and guide
treatment of congestive heart failure and other conditions. However,
use of the PAC has been controversial with varying opinions as
to its risk and benefits. New findings from a multi-center study
supported by the National Heart, Lung, and Blood Institute (NHLBI)
of the National Institutes of Health show that the PAC did not
significantly increase or decrease deaths or the number of days
hospitalized in patients with severe heart failure.
The results of the Evaluation Study of Congestive Heart Failure
and Pulmonary Artery Catheterization Effectiveness (ESCAPE) Trial
are being presented today in the late-breaking clinical trials
section of the American Heart Association’s Scientific Sessions
2004.
“Heart failure affects about 5 million Americans and the
numbers are growing. So it is important to find out the best way
to diagnose
and treat this serious condition. The ESCAPE study lays to rest
concerns that use of a pulmonary artery catheter in patients with
advanced heart failure is associated with increased death and hospitalization.
At the same time, the study suggests that PAC should not be used
routinely to guide therapy. This is an invasive procedure with
potentially serious complications and, without a definite survival
benefit, its use should be carefully evaluated,” said NHLBI
Acting Director Barbara Alving, M.D.
About 4 percent of the patients undergoing pulmonary artery catheterization
experienced complications, including cardiac arrest and infection
but there were no PAC-related deaths. Patients in both groups studied – those
who received a PAC and those whose therapy was guided by clinical
assessment – spent about 8 days in the hospital.
ESCAPE was a randomized clinical trial of 433 patients at 26
sites in the U.S. and Canada. The primary goal of the study was
to evaluate
whether the increased precision
that a PAC offers regarding heart and lung pressures translates
to improved patient survival and reduced time spent in the hospital
over 6 months compared with therapy primarily guided by clinical
assessment of physical signs and symptoms. Other study objectives
included comparisons of quality of life, ability to exercise, and
changes in the heart’s structure and function as measured
by echocardiograms. The study also sought to evaluate costs and
resources associated with the PAC. These results are not yet available.
Study patients had “Class 4” advanced heart failure
(severe physical limits, symptoms at rest, and low 2-year survival
rate). The average patient age was 56 years. Seventy-four percent
of the participants were male and 40 percent were minority. About
half (215) of the patients were randomly assigned to receive PACs
and 218 patients were assigned to the clinical assessment group.
Patients could receive any of the other standard therapies and
medications for heart failure.
The PAC is a thin catheter that is inserted via a neck vein and
passed through the right side of the heart into the pulmonary artery.
Once the catheter is in place, pressures and flows can be measured
from the right side of the heart and the lungs. A tiny balloon
is inflated to allow measurement of pressures from the left side
of the heart. Excess pressure can build up in the heart when it
is not pumping effectively. This can further weaken the heart and
lead to the hallmark symptoms of heart failure, which are shortness
of breath and fluid buildup in the lungs, ankles, and legs.
The PAC, which is used in 3 to 5 percent of heart failure hospitalizations,
is used not only to diagnose the specific part of the heart that
is not functioning or pumping properly but also to gauge the effect
of medications on heart function and symptoms. Physicians can use
the PAC to individualize medications for each patient.
The ESCAPE trial was led by Dr. Lynne Stevenson of the Brigham
and Women’s Hospital in Boston and coordinated by the Duke
Clinical Research Institute (DCRI). Dr. Robert Califf, director
of the DCRI, noted that this study demonstrates a critical principle
of technology assessment at a time when many new technologies are
being introduced in the hopes of improving health. “A diagnostic
technology, even if it provides accurate information, can be beneficial,
neutral, or detrimental, and the PAC is neutral,” said Califf.
Pulmonary artery catheterization, also called Swan-Ganz catheterization,
was introduced for use in 1970 to provide bedside assessment and
management of circulation and blood flow at a higher level of precision
than has been available from other tests. The device was quickly
embraced by the medical community and its use expanded beyond acutely
ill cardiac patients, before its benefits were actually proven.
There was no consensus regarding the risks and benefits of a PAC-based
strategy. In fact, by 1996 the controversy over excessive risks
was so high that several professional societies held a consensus
conference to review the literature and available data on clinical
benefit and safety. The consensus report, endorsed by several organizations
including the Society of Critical Care Medicine, called for a clinical
trial on the use of the PAC. In response to continued concerns,
the NHLBI and FDA convened a workshop on the PAC in 1997 and the
resulting report recommended a randomized clinical trial to test
its safety and effectiveness.
ESCAPE provided important information about the effect of the
PAC on patients’ quality of life, although it was not the primary
outcome tested.
“It was encouraging that patients in both groups had major
improvement in their symptoms and their ability to exercise. Patients
whose
therapy was guided by the PAC reported a greater improvement in
the value they placed on their own daily lives than the other group
of patients,” said ESCAPE principal investigator Stevenson,
who is co-director of the cardiomyopathy/heart failure program
at Brigham and Women’s Hospital. “While we don’t
know exactly how to interpret this information yet, the ESCAPE
trial emphasizes that we need to learn more about what matters
most to our patients as they face disabling symptoms,” she
said.
“We know that patients who received a PAC felt better,
but then why didn’t they have fewer deaths or hospitalizations?” asked
Stevenson, who presented the ESCAPE results at the American Heart
Association meeting.
According to Stevenson, the answer may lie in the fact that there
was a big variation in how PAC information was used to treat patients.
The study did not specify which medications or other types of therapy
would be used, she noted.
George Sopko, M.D., project officer for the ESCAPE trial and
Medical Officer with NHLBI’s Division of Heart and Vascular Diseases,
said that “ideally, another study would compare specific
choices of therapy.”
“We also need to find out how therapies could be adjusted
using non-invasive tests, such as echocardiograms, to provide similar
information to PAC but without
risks. In-depth analysis now underway of the ESCAPE echocardiogram data
should provide clues about these next steps,” said Sopko.
To interview Dr. Sopko, call the NHLBI Communications Office
at 301-496-4236; to interview Dr. Stevenson, call Amy Dayton Smith
at 617-534-1600.
NHLBI is part of the National Institutes of Health (NIH),
the Federal Government’s
primary agency for biomedical and behavioral research. NIH is a component
of the U.S. Department of Health and Human Services. NHLBI press
releases and fact
sheets, including a fact sheet on heart failure, can be found online at www.nhlbi.nih.gov. |