WEDNESDAY, July 25 (HealthDay News) -- People who suffer a tear to a major heart vessel, the aorta, have a better chance of surviving after their surgery if they do not also have clotting in the channel, new research shows.
The clots can occur when the layers of the aorta separate, according to a study in the July 26 New England Journal of Medicine.
Almost one out of three aortic dissection patients with blood clots in the channel, known as a false lumen, died after hospital discharge, according to a data review conducted by the University of Michigan Health System.
Every year, 10,000 people suffer a tear in the lining of the aorta, the body's largest blood vessel. In fact, it was this type of sudden cardiac event that killed actor John Ritter in 2003. Many patients with an aortic tear die before they can be treated, and those who survive with medical help face a one-in-four chance of dying within a few years. Very little is known about which of these patients have a good chance at surviving in the long term.
The University of Michigan researchers now propose a model that may help predict patient survival.
Their model focuses on blood clots that form in the false lumen, which forms when layers of the aorta separate. The channel is parallel to the true lumen, through which blood flows out of the heart and into the abdomen.
After an aortic tear, blood can enter the false lumen and get trapped there, forming a clot. Doctors can see these clots using medical imaging technology.
According to the study, the risk of post-hospital death is more than two-and-a-half times greater for patients who experience partial clotting of the false lumen than people without these clots.
"It appears that this may be a new predictor of which patients are most at risk -- knowledge that might help guide decisions about when it's wise to proceed with more aggressive treatment and when we can hold off," lead author Dr. Thomas Tsai said in a prepared statement. "But more research is needed," he added.
The researchers gathered data from 114 (mostly male) patients who had a false lumen upon hospital admission between 1996 and 2003. Of the total, 68 patients had a partially clot-filled false lumen, and 19 had a completely clotted false lumen.
By the end of the three-year follow-up period, almost 25 percent of the patients had died. The degree of clotting in the lumen strongly affected the risk of death: 13.7 percent of the patients with clear false lumens had died, compared with 31.6 percent of partially clotted patients and 22.6 percent of the completely clotted patients.
The data also showed that patients with a history of atherosclerosis ("hardening of the arteries") and aortic aneurysm were more likely to die during the follow-up period.
To learn more about aortic dissection, visit the American Heart Association.
SOURCE: University of Michigan Health System, news release, July 25, 2007