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

Edwards Lifesciences VP of Engineering Darshin Patel discusses the first-of-its-kind Sapien M3 TMVR system’s design, development and lessons for other medical device developers.

Edwards Lifesciences VP of Engineering Darshin Patel led the development of the new Sapien M3 transcatheter mitral valve replacement (TMVR) system from the very beginning.

This transfemoral TMVR system recently won the world’s first-of-its-kind approval with a CE mark for treating symptomatic (moderate-to-severe or severe) mitral regurgitation in patients who are deemed unsuitable for surgery or transcatheter edge-to-edge (TEER) therapy. (This minimally invasive system has not yet been approved by the FDA for use in the U.S.)

The Sapien M3 system uses nitinol, but not in the catheter-delivered replacement heart valve’s frame. Instead, the dual-implant system uses nitinol’s shape memory properties for the dock implanted inside the heart to anchor the replacement valve. (An illustrated video of the procedure is at the bottom of this post.)

Related: The Edwards Lifesciences Sapien M3 TMVR system uses nitinol in a new way

In an interview with Medical Design & Outsourcing, Patel discussed the M3 Sapien system’s design, development and lessons for other medical device developers. The responses below have been lightly edited for clarity and space.

Are there any modifications to the M3 valve or is it essentially a Sapien 3?

Patel: “The Sapien M3 valve was modified to be compatible with the dock and mitral valve anatomy by replacing the Sapien 3 paravalvular leak (PVL) skirt with a full-frame outer skirt and frame apex covers to respect the native mitral anatomy.”

How is nitinol used in the Sapien M3 dock and did your team learn any lessons about nitinol that might be helpful for other device designers and engineers?

Patel: “The Sapien M3 dock is made from a nitinol wire that is shape-set to obtain the intended configuration. In the early days, a laser-cut nitinol tube was also explored. However, the team chose to utilize a wire to simplify the manufacturing process. One of the key learnings was to continually look for opportunities to reduce the complexity of the design and find ways to borrow design elements from other Edwards devices that have already been proven. For material-specific learnings, understanding the repositionability of the implant is key in making sure the design and raw material specifications are robust to the intended number of reposition cycles.”

What was the biggest technical/engineering challenge with this new system and how did the team solve it?

Patel: “The biggest technical challenge was designing a dock and valve that were able to anchor to the mitral valve apparatus without damaging the native anatomy. This was achieved through numerous iterations varying different parameters of the dock and valve (i.e., dock wire diameter, dock shape set diameter, dock cover materials, valve cover materials) and evaluating them in various models through trial and error. Resilience in the early stages is critical.”

Were there other anchor approaches that didn’t pan out, and can you share any lessons learned from those attempts?

Patel: “While other anchoring approaches exist, the team focused on developing a method to anchor the Sapien 3 valve in the mitral position where an anchor did not already exist, leveraging the extensive experience of the Sapien valve in the mitral position.”

How did Edwards design the Sapien M3 system to minimize the risk of physician error during implantation?

Patel: “Edwards partnered with numerous key opinion leaders (KOLs) prior to human experience to provide feedback on the device and procedure and apply learnings from previous therapies in addition to extensive usability studies with the appropriate user groups. Once in the clinic, when new learnings arose, the team diligently investigated the findings to understand the root cause. The team then shared with the physicians and incorporated those learnings into procedure or patient screening updates.”

Were there other materials/manufacturing processes that unlocked this solution for TMVR, and was there anything the team learned that could be helpful for others in medtech?

Patel: “The innovation was really in the application of existing materials and manufacturing processes, leveraging ideas and processes from other Edwards products versus reinventing the wheel.”

Is it too soon to talk about the next generation of this system?

Patel: “The team continues to iterate the Sapien M3 system to further enhance patient outcomes and procedural ease of use, as well as expand the treatable population.”

What advice or guidance would you offer to device designers/engineers and other technical roles at device developers and manufacturers?

Patel: “If you are afraid to fail, you will never learn. As the saying goes, fail often and fail quickly, especially in the early days of product design. And engineers cannot fall in love with their designs. They need to look for continual improvement, even if they made the original design.”

“Finally, it’s critical for the engineers that designed the product to participate in the early human experience with their clinical counterparts so they can understand how the device is being used and what opportunities there may be to design out any potential problems. Many times, we wait for aggregate data to tell us what the areas of improvement may be, however, to innovate quickly, we need to almost predict the problem and start developing solutions in parallel to gaining clinical experience. This expedites the development pathway by running innovation and evidence generation in parallel, rather than in series, preventing a start and stop of clinical experience. Engineers working side-by-side with clinicians prior to human use can accelerate development.”

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