But it can still be five times more deadly if not repaired surgically, the researchers added.
Aortic dissection happens when blood rushes through a tear in the heart’s ascending aorta. This happens in about 3 of every 100,000 people. It mostly affects older men, who may experience a “knifelike, tearing pain through the back.” About 50% of patients will die before they reach the hospital.
In the study, researchers reviewed the cases of 5,600 patients from the International Registry for Acute Aortic Dissection between 1996 and 2018.
Researchers found that about 5.8% of the patients died within two days of arriving at the hospital, compared to the 1950s, when 37% of patients died in the first 48 hours. The death rate now is 0.12% per hour, compared to 1% to 2% per hour in the 1950s.
“We believe that advances in diagnosis and management, especially a focus on early surgical repair, may have contributed in part to these improvements in mortality for acute aortic dissection,” senior study author Dr. Kim Eagle said in a University of Michigan news release. He is director of the university’s Frankel Cardiovascular Center.
Patients who received only medical care, and not surgery, were much more likely to die.
Researchers found that about 24% of those treated medically died within two days, compared to 4.4% treated with surgery.
The findings were published recently in the journal JAMA Cardiology.
“Patients who were managed medically were likely not surgical candidates due to their co-morbidities,” said Dr. Bo Yang, a professor of cardiothoracic surgery at University of Michigan Medical School.
“The medically managed patients could die from aortic dissection-associated complications … which can be treated with surgery — or from their existing medical conditions, which could be worsened by the aortic dissection,” said Yang, who was not involved in the study.
About 1% of patients who would have had surgery died before it could happen, after an average of almost nine hours from being admitted to the hospital. Delays can be caused by the need to transfer to another hospital, which is needed in about 70% of aortic dissection cases, the researchers noted.
Eagle said that it had been thought that getting to surgery quickly was needed, but this study showed that surgery at a low-volume hospital could raise the risk of dying while undergoing the repair compared to having the surgery done at a high-volume hospital.
Death rates for the surgery were nearly three times higher when not done by a dedicated aortic surgeon, according to the study.
“Hospital mortality at a high-volume center … where aortic dissection patients are taken care only by highly experienced aortic surgeons, can be as low as 5%, while the same patient operated on at a low-volume center may be 20% or higher,” Eagle said. “With this new information, it is clear that the ‘cost,’ or risk, of a four-to-six-hour delay caused by [hospital] transfers is more than offset by the lower risk of surgery at experienced hospitals.”
Researchers suggested it would help to identify who is at risk before aortic dissection happens.
“There is a need to identify the high-risk population of aortic dissection, such as those with a family history of aortic aneurysm and dissection, especially at a younger age,” Yang said in the release.
The U.S. National Library of Medicine has more on aortic dissection.
SOURCE: University of Michigan, news release, Sept. 14, 2022