Accurate measurements of the heart's blood flow can help doctors treat people with severe congestive heart failure, but doctors haven't known if one invasive measurement tool, pulmonary artery catheterization, is worth the risk. According to research published in the October 5 issue of the Journal of the American Medical Association, patients who undergo the procedure—in which a catheter inserted into a blood vessel in the neck snakes a device into the chambers of the heart to measure blood pressure and flow—experience neither significantly greater risk nor significantly greater benefit. Yet there are consequences from the procedure, both bad and good.

Doctors at Brigham and Women's Hospital in Boston and at Duke University studied 433 people with congestive heart failure, a condition that causes fluid to build up in the lungs, stomach, and legs and results in shortness of breath and profound fatigue. They found that PAC patients died or were hospitalized at the same rate as those who didn't have the procedure. While PAC patients suffered more complications in the hospital than the other group, such as bleeding and infection, they indicated in a questionnaire that several months after returning home, their quality of life was better than the other group's.

The researchers don't know why PAC patients report feeling better, but one possible explanation is that the detail provided by the procedure allows doctors to better tailor treatments. "When you have more information, that allows you to adjust medications more precisely to the individual patient," explains researcher Lynne Stevenson, coauthor of the study and a professor of medicine at Harvard University.

Medical researchers disagree about whether doctors should use PAC without evidence of more substantial benefits. For now, most recommend the procedure only for patients with severe congestive heart failure. Other tests, such as examining veins in the neck, don't provide doctors with the same level of detail—though preliminary research suggests that one noninvasive procedure, the echocardiogram, does offer more information than a physical exam.

Find out more: Check out the U.S. News Heart Center for more information on congestive heart failure.