Stan Kepley remembered feeling dizzy while mowing his lawn. He remembered riding his bicycle in Steamboat, Colorado and how strange it was that he couldn’t keep up with his wife Linda. And there were times when his train crew gave him a hard time for being winded after he’d climbed the stairs to his locomotive.

Kepley, 62, figured the culprits were heat, the altitude — or maybe he was just getting old.

He was actually experiencing aortic valve stenosis, a heart condition that left untreated had a greater than 50 percent chance of killing him within two years.

“That’s worse than just about any cancer you can come up with,” said UCHealth cardiac surgeon Dr. Peter Walinsky of the prognosis for aortic stenosis. “It’s incredibly deadly, and it’s one of the most underdiagnosed and undertreated diseases, even though we can successfully treat it with an operative mortality of less than 1 percent.”

When the heart pumps, the aortic valve opens to let a burst of oxygenated blood through, then it closes again until the heart’s next beat. But aortic stenosis is a narrowing of the valve so that it doesn’t open all the way.

It is the most common and most serious of heart valve disease problems, according to the American Heart Association.

Aortic stenosis sometimes develops with age or, as in Kepley’s case, it occurs because the individual has a bicuspid aortic valve rather than a normal tricuspid, or three-leaflet, valve. No matter the reason, when the valve can’t open properly, it causes blood to be held back, increasing pressure in the heart’s left ventricle and backing up blood into the lungs. The more the disease progresses, the harder the heart has to work and the more often symptoms occur, said UCHealth cardiologist Dr. Brad Oldemeyer.

“Symptoms are the same no matter what age you are,” he said. “Whether you’re feeling shortness of breath as an athlete and exercising at high levels, or whether you’re 80 and limited to walking down the hall to lunch, when you have shortness of breath with your highest level of exertion, it’s a sign of concern.”

Along with breathlessness, a patient may notice symptoms including chest pains or pressure, a decline in physical ability and fainting.

“A lot of times the issue is found because a doctor will identify a heart murmur,” Oldemeyer said. “Aortic stenosis happens slowly, over months or years, and that’s part of the reason why it goes underdiagnosed. But it doesn’t have to be. It can be as simple as listening for a heart murmur, and if there is one, getting an echo(cardiogram). It’s something your primary care provider can listen for and help you with the next steps.”

Kepley’s doctor indeed heard a murmur about a year and a half ago, and Kepley chose to visit the UCHealth Heart Center in Loveland for further review. It was there that he was diagnosed with aortic stenosis and told he would be monitored until symptoms became such that the condition needed to be addressed.

Another factor leading to the disease being undertreated is that only one-third of those diagnosed decide to undergo the necessary surgery to rectify the problem.

Although the heart valve disease is associated with cardiac risk factors, such as smoking and poor diet, lifestyle changes won’t slow its progression.

“Once you have symptoms, it will need to be fixed,” Oldemeyer said. “It’s not about a lifestyle change. It’s about fixing it so that you can get back to your lifestyle.”

To correct aortic stenosis, cardiologists must replace the damaged valve with an artificial one, either through the traditional method of open-heart surgery or a 2011 FDA-approved procedure, transcatheter aortic valve replacement (TAVR). Both options are available at UCHealth hospitals in northern Colorado, metro Denver and Colorado Springs.

In November 2015, after a battery of tests, Kepley was told it was time to correct his stenosis with surgery.

“I came home and was in a bit of shock,” he said. “Even though I was 62 at the time, I thought I’d weathered the storm of life, and then they are telling me what has to happen next, and it’s like, wow, it’s right here in front of me. I didn’t want to do it, but I also wanted it behind me.”

The statistical prognosis for his disease if left untreated was top of mind for Kepley.

Because of damage Kepley sustained from medical radiation to his chest in the 1980s, he was classified as a “moderate risk” for open-heart surgery and therefore, qualified for TAVR.

Unlike open-heart surgery, TAVR is a minimally invasive surgical procedure that repairs a damaged valve without removing it. With TAVR, a team of heart surgeons and interventional cardiologists works together to place a collapsible artificial valve into the heart through a patient’s artery. When in position, it expands and pushes the old valve leaflets out of the way, and the tissue in the replacement valve takes over the job of regulating blood flow.

The procedure was approved by the FDA in 2011 but only for patients who were too high risk for open-heart surgery. The FDA later approved the procedure for moderate-risk patients, and now, a trial is underway to consider its efficacy for low-risk patients.

“Every patient we see at the (UCHealth) heart valve clinic is screened for the potential for TAVR,” Oldemeyer said.

Kepley had a TAVR procedure on Dec. 6, 2016. He was released from the hospital the following day and allowed to return to his normal activity within a week. Kepley attended cardiac rehab, and he said that in less than a month, he was back to his old self: hiking, hunting, fishing and biking.

“I can’t believe I just had heart surgery,” Kepley reflected. “They just messed with my heart — that’s the thing that keeps me going. It’s still hard to grasp. But now I’m enjoying life. I may have joined the Old Man Club, but it was a step I had to take. I couldn’t go around it, and if I did, I wouldn’t have lived long or had the quality of life I have now. I don’t hide the fact that I have TAVR — without it I wouldn’t be alive.”

Kepley returned to his job as a locomotive engineer for Union Pacific Railroad and several months later, he retired after 41 years with the railroad. He continues to enjoy the active things he loves to do and no longer struggles to keep up with his wife Linda.