U.S. regulators have approved a tiny mechanical valve for young children with troubled hearts, culminating years of effort in Minnesota to produce a dependable pediatric version of a common adult-sized medical device.
The Food and Drug Administration announced Tuesday that it has granted approval for Illinois-based Abbott Laboratories to sell the 15-millimeter Masters Series Mechanical Heart Valve with Hemodynamic Plus, making it the smallest mechanical valve available commercially in the world.
The device, which is the size of a dime, is small enough to be inserted into the heart of a newborn baby or toddler to correct an irregular blood flow caused by congenital valve defects. The device was invented at Little Canada’s St. Jude Medical and is partly manufactured in the state. Abbott acquired St. Jude last year.
“Any time you are a part of saving somebody’s life, it is something special. But there is a special spot in my heart ... for when you participate in the development of something that treats kids,” said Rick Olson, divisional vice president of product development for Abbott Labs’ structural heart business. “A lifesaving device like this could really extend a child’s life through adulthood.”
The 15-mm valve is intended for cases where a child’s heart defects are so serious that they can’t be fixed by any other means than having a new valve implanted. The two-leaflet valve is designed to replace a diseased aortic or mitral valve. Like other mechanical valves, the 15-mm version may require the patient to go on anticoagulation therapy to prevent clots from collecting on the device.
The 15-mm valve is a variation on the basic mechanical valve design that St. Jude has been making since the 1970s. A key design feature is the use of two leaflets made of a material called pyrolytic carbon, which is lightweight and inert when exposed to blood. The device requires no battery — the heart’s natural contractions and blood flow make it move.
Larger sizes of the Masters Series mechanical valve have long been on the market, but in 2010 the FDA encouraged device companies to address the lack of child-sized devices. Pediatric populations are often underserved by the medical device market, which leaves surgeons at children’s hospitals with fewer options than their colleagues in adult surgery.
Before this week’s approval, a surgeon who wanted to implant a 15-mm valve would have needed to apply for special permission under the FDA’s humanitarian exemption program or take part in a clinical study, or consider ways to make a larger size fit in a young child.
St. Jude launched a clinical trial in 2015 to study the device in 20 children nationwide. Although the results have not yet been published on clinicaltrials.gov, Abbott’s news release Tuesday said the single-arm study showed that the 20 patients had a 69 percent probability of survival at one year, and a 67 percent chance of not experiencing an adverse event.
Serious adverse events included blood clots on the device and bleeding in the brain.
“The approval of this smaller pediatric mechanical heart valve provides surgeons with a much-needed option for treating these vulnerable, high-risk children,” said a statement from Dr. Kirk Kanter, director of the heart transplant program at Children’s Healthcare in Atlanta, which was a major site for the study.