The Edwards Lifesciences Sapien M3 transcatheter mitral valve replacement system uses nitinol in a new way

The first-of-its-kind Edwards Lifesciences Sapien M3 transfemoral TMVR system uses nitinol to anchor the replacement valve in a patient’s heart.

Nitinol is commonly used in replacement heart valve frames, but that’s not how the new Edwards Lifesciences Sapien M3 transcatheter mitral valve replacement (TMVR) system uses the nickel-titanium alloy.

Like the Sapien 3 heart valve it’s based on, the minimally invasive Sapien M3 heart valve has a cobalt-chromium alloy frame that expands with a balloon after catheter delivery inside a patient’s heart, instead of using nitinol like many self-expanding cardiac implants.

What’s special about the Sapien M3 TMVR system is the dock that’s implanted in the patient’s heart before the replacement valve.

The Sapien M3 TMVR system became the world’s first approved transfemoral TMVR system this week when it won a CE mark for treating patients with symptomatic (moderate-to-severe or severe) mitral regurgitation who are deemed unsuitable for surgery or transcatheter edge-to-edge (TEER) therapy.

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The Edwards Lifesciences Sapien M3 TMVR dock

Edwards Lifesciences designed the system’s catheter-delivered nitinol dock to anchor the Sapien M3 valve by encircling and capturing the patient’s mitral leaflets, which creates “a stable and standardized landing zone” for the valve.

The Sapien M3 system uses the same steerable guide sheath (23 Fr inner diameter, 29 Fr outer diameter) to deliver both the dock and the valve. After accessing the patient’s right atrium via the femoral vein, the catheter punctures the septum to enter the left atrium. The system then introduces the dock through the mitral valve with a steerable catheter. (An illustrated video of the procedure is at the bottom of this post.)

“The dock wraps around the native mitral leaflets, which pulls them and the chordae inward toward the center of the dock, bringing the papillary muscles closer together,” Edwards Lifesciences explains.

The dock features radiopaque markers for visualization of positioning and placement. A nitinol paravalvular leak (PVL) guard expands in the mitral valve’s medial commissure before the dock is released; the dock is repositionable and retrievable until then.

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The Edwards Lifesciences Sapien M3 mitral valve implant

With the dock in place, next comes the Sapien M3 valve via the Edwards Commander M delivery system.

The 29mm Sapien M3 valve has a cobalt-chromium frame for radial strength and visualization under fluoroscopy and a full-frame polyethylene terephthalate (PET) skirt. The leaflets are made of bovine pericardial tissue treated with the ThermaFix process to mitigate calcification.

The Sapien M3 valve is crimped on the balloon, which inflates to expand the valve inside the dock before the delivery catheter and guide sheath are withdrawn.

Read more: Q&A with Darshin Patel, who led the Edwards Lifesciences Sapien M3 TMVR system’s development

“Mitral regurgitation is the most common form of valvular heart disease and these patients suffer with debilitating and often life-threatening symptoms,” Dr. Michael Mullen of Barts Heart Centre at St Bartholomew’s Hospital in London said in an Edwards Lifesciences news release. “The Sapien M3 system establishes a new pathway for care with its novel docking mechanism and transseptal access, providing an important new treatment option for patients unsuitable for surgery or TEER.”

Nitinol knowledge: Q&A with nitinol expert Ming Wu, former SVP of engineering at Edwards Lifesciences