While keeping the palm flat, if a person's thumb extends beyond the edge of the palm, they may be at risk of having an aortic aneurysm, according to researchers at New Haven, Conn.-based Yale University. The idea behind the test is that being able to flex the thumb to that extent is a possible indicator of connective tissue disease, including the aorta.
Researchers evaluated the self-administered thumb-palm test's accuracy among 305 patients undergoing heart surgery for a number of disorders, including aortic aneurysms.
The findings, published May 18 in the American Journal of Cardiology, showed patients who have a positive test, meaning their thumb can reach past their palm, had a higher risk of hidden aneurysm.
"Our study showed that the majority of aneurysm patients do not manifest a positive thumb-palm sign, but patients who do have a positive test have a high likelihood of of harboring an aneurysm," said John Elefteriades, MD, senior study author and director of the aortic institute at Yale New Haven Hospital.
While Dr. Elefteriades and his colleagues have taught the thumb-palm test to medical students for at least 20 years, it had never been studied in a clinical setting until now, according to a news release.
The findings suggest the self-administered test can identify aortic aneurysms in advance, which are otherwise difficult to defect before rupture.
Since aneurysms can take years to develop before rupturing, researchers said a positive test does not indicate immediate risk, and that not everyone who tests positive is harboring an aortic aneurysm.