Use of TAVR devices in younger patients with a longer life expectancy has raised concerns that valves could fail within the lifetimes of recipients. Valve-in-valve replacement allows physicians to fix the problem without repeat surgery. Larry Wood, group president of TAVR and surgical structural heart at Edwards Lifesciences, said at an investor event in December that he expects “valve-in-valve to be an increasing contributor over time.”

The downside to the valve-in-valve procedure is the risk of blockages. The leaflets of the failing valve stay in place and, if they are displaced, can cause coronary obstruction. One study found around 2.6% of people had obstructions during valve-in-valve TAVR, but the rate was as high as 7% for some devices.