U.S. hospitals that offer information about a common heart valve replacement procedure often explain the benefits but rarely mention the risks - including doubled risk of stroke - according to a new study.

Transcatheter aortic valve replacement (TAVR) was recently introduced as a less invasive method than open surgery for opening a narrowed aorta, the main artery carrying blood from the heart to the rest of the body.

“Part of the reason I was interested in this was I’ve seen advertisements for this procedure, and there is not so much emphasis on the risks,” said senior author Dr. Mark D. Neuman of the anesthesiology and critical care department at the Perelman School of Medicine of the University of Pennsylvania in Philadelphia.

When the aortic valve narrows, which can be congenital or more often caused by calcium deposits that develop with age, the heart must work harder to pump blood to the rest of the body. This may cause chest pains or blood backing up into the lungs, according to the National Institutes of Health.

About two percent of people over age 65 develop this narrowed valve, called aortic stenosis.

It may not require invasive treatment, but if it does, the valve can be replaced with open aortic valve surgery, done through a large incision in the chest. In 2012, the Centers for Medicare and Medicaid Services approved coverage of TAVR, which achieves the same thing by inserting the new valve through a catheter.

For the new study, Neuman and his coauthors examined the websites of all 317 hospitals in an official TAVR registry, 262 of which had their own web pages describing the procedure.

Of those, 260 listed at least one benefit of TAVR relative to open aortic valve replacement, most often that it is less invasive, recovery is quicker, it does not require the use of a heart-lung machine during surgery and quality of life is improved.

Only 69 websites, roughly one quarter of the hospitals, listed any risks of TAVR.

Patients who have the transcatheter procedure have twice the risk of stroke compared to patients who have open surgery, the study authors note, but only 48 websites mentioned stroke at all, and even fewer quantified the risk.

Only a small number of sites mentioned the potential for kidney injury or need for a new pacemaker, more repeat hospitalizations and more frequent need for additional procedures, all of which are associated with TAVR, the authors write in JAMA Internal Medicine.

“While some risks are higher with TAVR, others are lower,” said Dr. Yael Schenker of the Palliative Care and Medical Ethics section at the University of Pittsburgh, who wrote a commentary accompanying the new research.

“The decision to pursue TAVR or (open surgery) depends on a determination of a patient's individual surgical risk as well as his/her preferences,” Schenker told Reuters Health by email.

Patients should have access to clear and balanced information about procedural risks and benefits, as well as detailed outcomes data, but it is hard to find reliable, balanced information, she said.

In the commentary, Schenker notes that patients may believe hospital websites are educational portals when in fact they are presenting promotional materials. Hospital advertising is subject to less stringent regulation than direct-to-consumer drug advertising, and the standards can be even more lax for nonprofit hospitals, she writes.

Most of the hospitals were large nonprofit, nongovernmental facilities, with at least some teaching affiliation and located in an urban area.

“The decision on whether or not this could be an appropriate procedure should really be something that starts out with the patient talking to their doctor, family members and support system,” Neuman said.

“There’s no simplistic way that a website could replace that,” he said. The information on a hospital website may set the tone for how a patient thinks about TAVR, which is important, he said.

“We feel that the websites and the information that’s on the websites have the potential to influence decision making in a meaningful way, and by providing better information on what the downsides could be they could portray a more balanced picture,” Neuman said.

Since TAVR is a very new procedure, researchers are still learning a lot about how it is being used, how it should be used and whether or not those differ, Neuman said.

“At this point I am not aware of studies that have shown it is being used inappropriately,” he said.

Regardless, “consumers should recognize that the information they see on hospital websites may not be the whole story, particularly as it pertains to downsides,” he said. “That’s a fairly obvious thing but it deserves to be said.”