During a routine checkup about 10 years ago, my mother’s doctor picked up a heart murmur. He sent her to a heart specialist who ordered some tests, including an ultrasound. The diagnosis was aortic stenosis.
I’d never heard of it before, but it’s yet another thing that can develop with age. It happens in about three percent of people over the age of 75.
To understand what it is and how it’s treated, I turned to Maine Medical Center. U.S. News & World Report recently recognized MMC as a best regional hospital. It also rated it as high performing in nine out of nine procedures and conditions, including aortic valve surgery. So, I felt pretty confident I’d get accurate information from its Chief of Cardiac Services, Dr. Douglas Sawyer.
Anatomy of the heartWe’ll begin with a brief anatomy lesson. There are four valves in the heart — aortic, tricuspid, pulmonary and mitral. Their job is to see that blood flows into your heart from your lungs and then flows out of your heart to the rest of the body. It’s important that it moves in only one direction.
Since this post is about aortic stenosis, we’ll focus on the aortic valve. That’s the one in the image above. It allows the blood to flow out of the heart to the rest of the body.
Inside the valve are three leaflets or cusps. They open and close with every heartbeat. Think of how many beats that would be over 60 to 80 or more years. “When we’re born and when we’re young, they’re thin and pliable,” says Dr. Sawyer. “But they’re also strong so they can open when the blood flows out and close to prevent blood from flowing back into the heart.”
They get a bit beaten up over time and become calcified. “That calcification can build up with age,” says Dr. Sawyer, “and prevent the leaflets from opening as well. This can eventually narrow the valve. Enough that people develop symptoms because the blood’s not getting out of their heart as well.”
Aortic stenosis is the term for this narrowing. It’s a fairly slow process that goes on for many years, sometimes decades. In time, it causes heart failure. The heart muscle can become weak and unable to pump the blood your body needs to survive.
Symptoms of aortic stenosis
My mother’s stenosis has progressed to moderately severe. So far, she hasn’t shown any symptoms. “When people do develop symptoms,” says Dr. Sawyer, “it’s very predictable that without [treatment] this is likely to take their life. Without symptoms, the narrow valve is generally not a major problem. But when someone does have symptoms due to aortic stenosis the only effective treatment is aortic valve replacement.”
These are the symptoms we watch for:
- Shortness of breath
- Fainting. Happens if there isn’t enough blood flowing into your head
- Angina, chest pressure or chest tightness. Happens when the heart itself isn’t getting enough blood.
When she was first diagnosed, the only treatment option was open heart surgery to replace the aortic valve. Now, a minimally invasive procedure is available for some patients. It’s called transcatheter aortic valve replacement or TAVR. At MMC, patients must be evaluated by a team of specialists and undergo a series of tests to determine if treatment is necessary and which approach is the best option.
Open heart surgery is generally reserved for people with severe stenosis. In other words, they are at high risk of death or complications. The damaged valve is removed and replaced with either a mechanical valve or one made from a pig or a cow.
Until recently, TAVR was also reserved for people at high risk. In early August (2016), the U.S. Food and Drug Administration (FDA) gave the ok to use two specific TAVR systems in people with aortic stenosis who are at intermediate risk for death or complications associated with open heart surgery. Another TAVR system may be approved for use in lower-risk patients in the near future.
As I mentioned, TAVR is a minimally invasive procedure. Simply put, a catheter is threaded up through an artery in the leg into the aortic valve. A balloon is inflated to open up the valve and a new valve is placed inside the damaged valve. Part of the valve is made out of pig or cow tissue and part of it is mechanical.
When the procedure is over, people usually feel better quite rapidly, says Dr. Sawyer. That’s because the heart is no longer under such enormous pressure. With aortic stenosis, the pressure can get well over 200.
“Think about that,” says Dr. Sawyer. “Normal blood pressure is in the 100 to 120 range systolic. Let’s say you need that to live. [With aortic stenosis,] inside the heart muscle pressure is well over 200 in order to drive the blood flow across this tiny narrow opening. So suddenly, you open up that door and the pressure and blood flow can normalize. That’s a huge relief of strain.”
Age is not the only risk
So far, we’ve only talked about cardiac stenosis related to aging. Some people are at risk at a younger age. Particularly people who were born with two of the three valve leaflets fused. It’s called a bicuspid valve and it’s generally inherited. “People with a bicuspid valve are much more likely to develop aortic stenosis at a younger age,” says Dr. Sawyer. “It’s usually people in their 50s or 60s who are getting bicuspid aortic valves replaced. It’s probably more common than we think.”
Because it’s inheritable, it’s important for people with a bicuspid valve to let other family members know.
As for everyone else: “We’re all at risk for all kinds of stuff as we get older,” points out Dr. Sawyer. “Our bodies wear out and this is one of those things. If someone develops aortic sclerosis at a certain age, the longer he or she lives, the worse it’s going to get. But not everybody develops it. Lots of people have relatively normal aortic valve function and aren’t going to need a valve.”
My mother’s decision
Someday, my mother will need a new valve. Only she doesn’t want one. She says she’s lived a good life (we just celebrated her 90th birthday) and when it’s her time, it’s her time. It’s a difficult thing to hear, but I think it’s important to have end-of-life conversations and to respect people’s wishes.