Key Takeaways
- Using mathematical modeling, researchers have streamlined the shape of mechanical heart valves.
- The new shape could potentially reduce the need for blood thinners and could be scaled for pediatric patients.
- The new design is just beginning animal trials, so this potential treatment will not be available in the near future.
No two human hearts are the same, which poses a challenge for doctors trying to treat heart patients, especially those that require replacement valves. A new study by the University of British Columbia Okanagan’s Heart Valve Performance Lab (HVPL) however, made a breakthrough that may revolutionize heart valve replacement.
The study, led by Hadi Mohammadi, PDF, PhD, found that by creating a specific curvature to the two leaflets inside the new bi-leaflet valve, dubbed the Apex valve, they could eliminate or greatly reduce clotting issues, which are inherent in patients with mechanical heart valves. The January study was published in the Journal of Medical Engineering and Technology.
Replacement heart valves have been in use since the 1960s, but have always had limitations due to the potential for blood clots. While tissue valves eliminate clotting problems, they have a finite lifespan and have to be replaced in 10 to 15 years. Mechanical valves last a lifetime but typically come with a prescription for blood thinners.
Thrombogenicity
In the case of mechanical heart valves, blood clots can occur when there is not even flow through the valve—areas that capture blood and keep it still, such as around the hinges or the leaflets. Those clots can then travel through the cardiac system to the brain, causing a stroke, or to the kidneys or other organs.
Mohammadi and his team approached the design of the bi-leaflet valve from a different direction, he tells Verywell.
“Up to this point, all the progress in mechanical valves has been incremental,” Mohammadi says. “This time, we just optimized the shape that we thought would be best for dynamic blood flow through a vigorous mathematical solution. We got to a point in the lab that conceptually, even though it looks like a mechanical valve, we’ve optimized the whole performance through mathematical modeling to suggest the best shape.”
The resulting Apex valve features specifically curved leaflets to decrease pressure drops through the valve and smooths the passage of blood past the hinges, which should, in theory, help eliminate clotting issues.
What This Means For You
Mechanical heart valves eliminate the need for replacement surgery but come with risks of blood clots. The Apex valve may be able to eliminate the need for blood thinners in mechanical valve recipients, which could result in a much better quality of life. However, with animal trials just beginning, it may be years before this becomes a new treatment option.
Eliminating the Need for Blood Thinners
In addition to creating a long-lasting valve that has the same functionality as a tissue valve, the Apex valve could eliminate the need for blood thinners, which are currently the standard for anyone with a mechanical heart valve.
Arnar Geirsson, MD, chief of cardiac surgery at Yale School of Medicine in Connecticut, tells Verywell that this development alone would be revolutionary.
“It seems very innovative, how the valve leaflets are designed and totally different than the way they’ve been designed before,” he says. “There’s minimal resistance across the valve itself, which would be very beneficial, especially in smaller valve sizes…The real need is for anticoagulation. If this results in lower need for anticoagulants like Coumadin, that would revolutionize the field of valve surgery with mechanical valves.”
Coumadin, the brand name for the drug Warfarin, is prescribed to nearly all mechanical heart valve recipients, but it’s not without its side effects or risks. As a blood thinner, users risk severe bleeding while using it. Special dietary considerations must also be made when on the medication.
“Obviously, there’s a risk of thinning the blood too much,” Geirsson says. “So there’s a fine line. Coumadin is the only anticoagulant that’s approved for use with mechanical valves and there is good control of it. But there are certain populations that have difficulty taking these medications.”
Use in Pediatric Patients
Although Mohammadi and his team designed the Apex valve based on the aortic valve, he says that it would be customizable to fit any valve in the heart. It could also be scaled down for use with pediatric patients.
“Although we designed this valve for the aortic position, it would be customizable for the mitral position as well,” Mohammadi says. “The key factor would be the size. Right now, we don’t have a mechanical valve that is small enough to be used in infants. I think this is a very good candidate to be sized down super small, the size of a chickpea.”
More Research Needed
The study has only gone through theoretical trials thus far. Now, Mohammadi says, it will move on to animal trials. He expects it will be several years before the Apex will be available for humans.
In addition to going through animal and human trials, Mohammadi says he’s interested in finding a way to use transcatheter surgery—a minimally invasive heart procedure—to insert the valves.
“Right now, this valve is designed for open-heart surgery,” Mohammadi says. “In the continuation of this project, we’re working on designs to convert it in a way that it could be delivered by transcatheter technology. We believe that eventually all medical technologies eventually need to be delivered using catheters.”
Geirsson says that mechanical heart valve placements have actually decreased in popularity in recent years due to the ability to place tissue valves using transcatheter technology. If scientists can combine the longevity of the mechanical valve and the lower risk of transcatheter surgery, the world of heart surgery could be revolutionized.