By Tamara Mathias

(Reuters) – Non-invasive heart valve replacement systems from Medtronic Plc and rival Edwards Lifesciences Corp proved as good or better than open heart surgery in younger, more active patients for whom the surgical option was deemed low risk, according to trial results that had been scheduled to be presented on Sunday.

Both companies already have approvals for their TAVR (transcatheter aortic valve replacement) systems for use in patients too frail to endure surgery and those deemed at intermediate risk. Approvals in low-risk patients would open up a large new population for the devices seen as vital growth drivers for the companies.

An estimated 165,000 low-risk patients suffer from severe aortic stenosis each year in the United States, Western Europe and Japan, a condition that can lead to heart failure in as little as two years, Medtronic said.

With TAVR, the replacement heart valve is threaded into place through an artery via catheter, sparing patients chest-cracking surgery.

“When I do these patients in the morning, (later that day) I find them sitting in a chair, eating dinner, asking when they can go home,” said Dr. Michael Reardon, who led the Medtronic study. “As a heart surgeon, there is no incision I can make that’s small enough to allow my surgical patients to do that well.”

Edwards, which holds about 70 percent of the U.S. TAVR market, said it expects the global market to double to about $7 billion in 2024. The two companies have similar market shares outside the United States.

The Edwards Sapien 3 TAVR system proved superior to surgery on the main goal of its 1,000-patient trial, a composite of rate of stroke, death and rehospitalization one year after the procedure. The rate for TAVR was 8.5 percent versus 15.1 percent for surgery, data unveiled at the American College of Cardiology scientific meeting in New Orleans showed.

At 30 days, the Sapien also resulted in a lower rate of stroke – 0.6 percent versus 2.4 percent – which had been the primary safety concern when these systems were first introduced.

Medtronic’s rival Evolut TAVR system met the main goal of its so-called non-inferiority trial in more than 1,400 low-risk patients, proving as safe and effective as surgery, data presented at the same meeting showed.

The combined rate of all-cause death or disabling stroke after two years was 5.3 percent for Evolut versus 6.7 percent for surgery, a difference considered not statistically significant.

At the 30-day mark, Evolut was significantly better on safety. With TAVR, the composite rate of death or disabling stroke was 0.8 percent versus 2.6 percent for surgery. TAVR was also better on other safety measures after 30 days.

TAVR systems can cost about five times as much as traditional replacement heart valves, providing a significant source of revenue for the companies. But they can be more cost effective overall due to much shorter hospital stays and recovery times.

Jefferies analyst Raj Denhoy said he expects the TAVR market to grow in both size and competition, with Boston Scientific’s Lotus system poised for potential U.S. approval this year.

TAVR “is pretty dramatic technology and it should be used in a lot more patients than it’s being used in already,” Denhoy said.

(This story corrects the day of the scheduled presentation, typo on number of patients in paragraph 9)

(Reporting by Tamara Mathias in Bengaluru; editing by Bill Berkrot)