Medtronic suffered a regulatory and competitive setback Wednesday after a U.S. Food and Drug Administration advisory panel expressed concerns about Symplicity Spyral, a device to treat hypertension.

The same panel had much more favorable findings a day earlier for a competing product from another manufacturer, ReCor Medical.

If ReCor wins FDA approval and Medtronic doesn't, ReCor would have the only device of its kind in the U.S. It's seen as potentially a very big market: Minneapolis-based Medtronic said last year the technology could be a "multi-billion-dollar opportunity" by the end of the decade.

High blood pressure is one of the most common ailments in the U.S., affecting more than 122 million Americans, according to the American Heart Association.

Symplicity Spyral is a renal denervation (RDN) device that uses radio waves to reduce hypertension and lower blood pressure. RDN has been touted for patients who have not seen improvements with medication and other treatments. The technology has been "investigational" in the U.S., where no RDN devices are yet approved for use.

Symplicity Spyral is approved for use in 70 countries outside of the U.S. Medtronic acquired its RDN technology with its $800 million purchase of Ardian in 2011.

On Wednesday the FDA's Circulatory System Devices Panel gave unanimous support to the safety of the Medtronic device. But on the key question of whether the device's benefits outweighed its risks the panel voted 6-7, a loss for Medtronic.

For ReCor's Paradise Renal Denervation System the panel voted 10-2 that the benefits outweighed the risks. California-based ReCor is owned by Japanese firm Otsuka Medical Devices.

The recent vote does not necessarily mean Medtronic will be denied FDA approval for Symplicity Spyral, but the panel votes are an important consideration for the agency's ultimate decision.

"We think Medtronic faces even more of an uphill battle now and skew negative on an eventual approval," wrote Robbie Marcus, an analyst with J.P. Morgan, in a research note analyzing the panel's vote.

Marcus said that he sees a "small chance" for Medtronic securing FDA approval for Symplicity Spyral based on its strong safety profile.

Mike Matson, an analyst with Boston-based Needham & Co., said given the "long and costly RDN program combined with multiple disappointments along the way," Medtronic would likely abandon RDN if it doesn't win FDA approval.

"We appreciate the robust conversation that occurred prior to the vote," said Jason Weidman, Medtronic senior vice president and president of its coronary and renal denervation business, in a statement. "We will continue to collaborate with the FDA on bringing a new option to the millions of people living with high blood pressure."