A panel of outside advisers to the U.S. Food and Drug Administration voted unanimously, with one abstention, that the benefits of the Sapien device outweigh its risks for people who need a new heart valve but face a higher risk of dying from open-heart surgery.

The FDA usually follows panel recommendations, although it is not required to, and will make a final decision in the future.

Shares of Edwards edged up 0.5 percent to $91 in post-market trading, as analysts said a positive recommendation had largely been factored into the share price before the meeting.

The valve is widely considered to be Edwards' most important new product, and was already approved last year for those deemed too sick to have the open-heart surgery.

Devices like Sapien, as well as sophisticated non-surgical techniques, are seen as the next frontier in the battle against heart disease as drugmakers produce fewer new medicines to fight the world's leading cause of death.

The Sapien device is meant for people with aortic stenosis, when the aortic valve that allows blood to leave the heart does not fully open, decreasing blood flow and potentially preventing it from reaching the brain and the rest of the body.

About 250,000 Americans have severe symptoms of the disease, and about two-thirds of them undergo surgery to treat it.

A bad aortic valve commonly requires open-heart surgery, during which the ribs are sawed open, the heart is stopped and a new valve is sewn in place. But thousands of people each year are considered too sick to get the surgery, or have other health conditions that make it risky.

With an Edwards' Sapien transcatheter heart valve -- the first such device in the United States -- a catheter guides the new valve to the heart through the femoral artery in the groin or a small incision between the ribs. The valve costs about $30,000 and is made of cow tissue and polyester supported with a stainless steel mesh frame.

Doctors say this and a similar device being developed by Medtronic Inc will eventually become the standard of care.

In pivotal clinical trials, Edwards said the Sapien led to a slightly lower death rate and dramatically shorter recovery times and hospital stays than chest-cracking open-heart surgery.

However, FDA advisers were concerned about higher stroke risk with the device compared to the traditional surgery, as well as an issue known as aortic leakage, when the valve does not seal properly and can send blood back into the heart.

"I think we are in belief that the totality of the data demonstrate a reasonable assurance of safety and efficacy," said Dr. Warren Laskey, the panel chair and a cardiologist at the University of New Mexico School of Medicine.

"There are questions that remain unaddressed, but they don't seem to impede our acceptance of the totality of the data."

The panelists were also worried about clinical trial data that showed people who had the device inserted through the ribs -- known as a transapical procedure -- had a higher mortality rate after one year compared to an insertion through an artery in the leg.

The advisory panel voted 10 to 2 that the device was safe, and 12 to 0 that it was effective.

Sapien is considered to be one of the most important growth drivers for Edwards, especially if the company gets approval for the broader use, potentially doubling the number of eligible patients, analysts say.

Analysts have pegged the worldwide market for transcatheter aortic valves at more than $2 billion a year.

"A broader indication for high-risk patients would enable multi-disciplinary heart teams to choose the approach best suited to their patients' needs, including for the first time a transapical delivery option," Edwards' chairman and chief executive Michael Mussallem said in a statement.

(Reporting by Anna Yukhananov; Editing by Bernard Orr)

• A Permanent Economic Emergency