Jan. 16, 2002 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 http://www.med.umich.edu/cvc.
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