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ANN ARBOR,
MI - Those who have lived through it describe an aortic dissection
as the most painful thing that ever happened to them. Blood, surging
from the heart into the main artery, forces open a tiny rip in the
aorta's lining that grows and threatens to burst like a dam in a
flood.
Many of those
who experience this sudden, unpredictable and hard-to-diagnose crisis
never live to tell the tale. Nearly one in three dies before leaving
the hospital despite recent advances in diagnostic tools and surgical
treatment, according to a new study published in the Jan. 15 issue
of the journal Circulation by an international team of researchers.
The odds of death were even higher for women, patients over 70,
and those who didn't or couldn't have surgery to fix the rip.
But besides
showing aortic dissection's danger, this analysis of the largest
and most representative group of patients ever studied is providing
hope that more patients could get help quickly, avoid a mistaken
diagnosis of heart attack or stroke, and be more likely to survive.
Based on their
findings, the researchers have discovered key characteristics that
can help identify patients who are more likely to die quickly -
and therefore guide physicians and patients in making swift treatment
decisions, including surgery or measures to prevent complications.
The study was
performed by the International Registry of Acute Aortic Dissection
research team centered at the University
of Michigan Cardiovascular Center. It looked at the records
of 547 patients treated at 18 large hospitals in six countries for
type A acute aortic dissections, the most serious and most common
kind of this rare condition. The researchers looked at 290 variables,
from age and gender to blood pressure and previous medical history,
to see which ones were statistically most common to those who died
-- or those who lived.
Their efforts
yielded a seven-item checklist that assigns a score to each characteristic
a patient has. "The higher the total score, the more likely
a patient is to die before leaving the hospital," says lead
author Rajendra Mehta, M.D., a clinical assistant professor of cardiology
at the U-M Medical
School. "Combined with other knowledge about who is best
suited for surgery or other interventions, it can be used by physicians
anywhere to talk with patients about how to proceed."
Mehta and senior
author Kim Eagle, M.D., the Albion Walter Hewlett Professor of Internal
Medicine and chief of clinical cardiology at the U-M
Health System, worked with other U-M researchers and their IRAD
colleagues to assemble the patient records and the predictive tool.
The collaboration has helped produce the largest collection of aortic
dissection patient data ever; since only about 5,000 to 10,000 people
each year experience an aortic dissection, previous studies have
been small or only included people who had surgery.
The patients
whose records they looked at had a mean age of just under 62, were
65.5 percent male, and had surgery for their dissection in 80 percent
of the cases. Twenty-seven percent of those who had surgery died
during their hospital stay, versus 56 percent of those who didn't
have surgery, leading to an overall in-hospital death rate of 32.5
percent.
Among all the
patients, seven clinical characteristics seen upon presentation
emerged as statistically most likely to be present in those who
died before leaving the hospital. Each one was given its score on
the IRAD checklist according to its predictive significance.
The seven clinical
characteristics are: age over 70 years; female gender; abrupt onset
of chest, neck or back pain, which may mean more severe and sudden
tearing; abnormal electrocardiogram reading on presentation; pulse
deficit on presentation; kidney failure on presentation, signaling
a lack of blood to the kidneys; and hypotension, shock or tamponade
on presentation, signaling a lack of blood pressure and flow.
"We hope
this will be a useful bedside tool for physicians as they counsel
patients and their families, even as we think it will also serve
as a research tool that could help assess new diagnostic and therapeutic
approaches for this condition," says Eagle. "It's important
to note, though, that it applies only to those with type A acute
dissections, and that we did not look at the longer-term outcome
for those who left the hospital alive."
Besides Mehta
and Eagle, the study's other named authors are Toru Suzuki, M.D.,
Peter Hagan, M.D., Eduardo Bossone, M.D., Dan Gilon, M.D., Alfredo
Llovet, M.D., Luis Maroto, M.D., Jeanna Cooper, M.S., Dean Smith,
Ph.D., William Armstrong, M.D., and Christoph Nienaber, M.D.
For more information
on the U-M Cardiovascular Center, visit www.med.umich.edu/cvc.
Written
by Kara Gavin
For more
information, contact Kara Gavin or Carrie Hagen, UMHS Public
Relations, 734-764-2220, or by e-mail.
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