Nothing seemed to slow Ed Papelian down during the past 94 years.

The former World War II bomber pilot worked out at 5 a.m. every day. He regularly played table tennis with his buddies and even took up water volleyball a couple of times a week.

But in July, Papelian found climbing just a few stairs left him fatigued and faint. His age wasn't the problem. Turns out, he was suffering from severe aortic stenosis, a narrowing of the aortic valve that prevents it from properly opening and closing. That causes the heart to weaken. As many as half of those with severe aortic stenosis die within a year.

Papelian needed his aortic valve replaced to live. But at 94, his age made him a poor candidate for valve replacement through open heart surgery.

Then, another treatment option emerged. Medtronic was in the midst of medical trials in the U.S. for a new CoreValve device that replaces a diseased aortic heart valve without open heart surgery.

Now, three months after receiving his new valve, the Novi, Mich., man is feeling stronger. A return to working out and water volleyball is in the works, he said. Last week, Papelian spoke at Medtronic's annual employee holiday program.

"I am elated that they gave me my life back," he said.

The success of CoreValve could also prompt elation at Medtronic. The potential market is significant. An estimated 300,000 people worldwide suffer from severe aortic stenosis -- 100,000 of them in the U.S.

The condition typically develops in people from age 50 to 70.

For most, the way to treat the disease is through open-heart valve replacement surgery. But a significant number of severe aortic stenosis patients are at high risk for open-heart surgery, with about one-third of all patients ineligible for such a procedure.

Thomas Gunderson, a senior analyst with Piper Jaffray & Co., estimates that it will be a $1 billion market in the U.S. alone.

Medtronic, however, will not be the first to tap that market in the U.S. Edwards Lifesciences in Irvine, Cal., already has been approved by the FDA for sale in this country. Gunderson said Medtronic and Edwards have about a 50-50 split of the market in Europe, where CoreValve has been available since August. He estimated that Edwards Lifesciences will make $150 million to $200 million on its valve in its first year of U.S. sales. Little Canada-based St. Jude Medical Inc. is also working on a transcatheter valve.

"So it's a big deal," Gunderson said.

Surgeons insert the replacement valve through a small opening in the femoral artery, winding their way through arteries up to the aorta. Medtronic's valve is made from pig cardiac tissue and is mounted on a self-expanding frame. Once in place, it takes over for the diseased aortic valve and helps oxygen-rich blood flow into the aorta and circulate throughout the body.

Medtronic's U.S. clinical trial has been underway for more than a year and will involve nearly 1,400 patients at approximately 40 hospitals by next summer, according to Medtronic. Patients considered a high risk for open heart surgery will be randomly selected for CoreValve; other high risk patients will have their aortic valve replaced through open heart surgery.

Awaiting FDA approval

Patients deemed extreme risk will automatically get the CoreValve treatment. All patients' progress will be followed for a year after surgery. A Medtronic spokeswoman said the company anticipates FDA approval in 2014. Doctors have implanted the Medtronic device in more than 20,000 people living in more 50 countries.

Until July, Papelian showed no signs of being anything less than hale and hearty. He flew a B-26 Marauder on 25 bombing missions over Italy during the war. He later served 28 years in the Air Force Reserves before retiring as a lieutenant colonel. He owned a dry cleaning plant. He sang in the church choir for 75 years and, his children say, he's a pretty good dancer.

After he started feeling fatigued last summer, the doctor at his senior living community sent him to the emergency room. He needed oxygen 24 hours a day. His condition plunged.

Untreated, Papelian said, he had only a few months to live. His daughter and son-in-law learned about CoreValve, and Papelian landed in the U.S. pivotal trial in Grand Rapids, Mich., with Dr. John C. Heiser.

Papelian had the surgery Sept. 15 and began feeling better immediately. Medtronic called and asked him to speak at their holiday party. His children joked that it didn't take their dad long to agree. On Dec. 16, he stood before 1,200 people at Medtronic headquarters and, in a strong voice, spoke of "my journey for renewal."

At the end, he declared that "every day, I'm regaining my full strength."

He's rejoined "the Romeos" -- a group of guys who regularly meet for lunch. A return to dancing, he said, isn't far behind.

James Walsh • 612-673-7428