A top Abbott executive explains how the company’s FlexNav delivery system could make the Portico TAVR competitive.
The Abbott Park, Illinois–based medtech company in September announced FDA approval of its Portico with FlexNav TAVR system, more than a year after it secured CE Mark approval in Europe. For now, the approval covers symptomatic, severe aortic stenosis associated with a high or extreme risk for open-heart surgery.
The Portico valve boasts a self-expanding design with intra-annular (within the native valve) leaflets. The Portico’s creators designed its structure to provide optimal blood flow when placed inside a patient’s natural valve. It also preserves access to the critical coronary arteries for future interventions.
But Santosh Prabhu — divisional VP, product development of Abbott Structural Heart — says the FlexNav delivery system is the area where the real ingenuity lies.
“I think it’s a major innovation in how the valve is delivered, based on the innovation that has gone into the design of that delivery system,” Prabhu said during an interview that originally aired in November on our DeviceTalks Weekly podcast.
Abbott wanted to create a TAVR delivery system that was flexible, safe, able to get through tough anatomies, and easy to use.
“The smoother the delivery is, the better it is. The more accurately the doctor is able to place the valve, the better outcomes he gets, the better for the patients,” Prabhu said.
Here are five advances that Abbott incorporated into FlexNav:
1. Strategic use of hydrophilic coatings
Prabhu and his team took a hydrophilic coating and used it on specific areas of the catheter to provide lubricity through tough-to-navigate vasculature. He described the coating as a common material used infrequently in TAVR delivery systems.
The coating, Prabhu said, “allows us to reduce the friction as we navigate through that tortuous anatomy.”
The coating placement had to be well thought out because some parts of the delivery system that are interacting with human anatomy need the reduced friction — but others don’t because they need to anchor.
2. A low profile
The Abbott engineers and designers were able to drive the size of the FlexNav catheter down to 14 Fr, which Prabhu said is the lowest profile in the industry. “The low profile is what improves the deliverability of the catheter, but to get to the low profile, there’s a lot of engineering.”
“We have to make sure that we pick the right components, the right tolerances, the right blend of materials,” Prabhu said. “Catheter design is more of an art than a science in many ways.”
Abbott innovated in how it used standard catheter materials, giving close scrutiny to their size and braiding configuration. . “The team had to work through several different iterations,” Prabhu said “Not all of them were right. But as we progressed, we got closer and closer to the design goals.”
3. An integrated sheath
Prabhu and his colleagues also created an integrated sheath that could accommodate the catheter’s size: Doctors can go sheathless or use the sheath integrated into the FlexNav system.
“Instead of using a secondary sheath, it’s built into our product, which is one of the reasons we were able to drive down the profile,” Prabhu said.
4. A stability layer
A stability layer in the catheter, according to Prabhu, helps take the guesswork out of TAVR deployment.
In a TAVR procedure, a doctor maneuvers the catheter when placing the valve to ensure it is at the right location. “Now, with the stability layer that we have incorporated, he necessarily doesn’t have to do that,” Prabhu said.“Wherever you decide the valve needs to go, you start the deployment process, and the valve deploys in that location. He doesn’t have to maneuver or rotate the catheter or move the catheter front and backward.”
5. Better benchtop testing
Clinically relevant benchtop models — including 3D printed and silicone — also played an important role. “There was a lot of innovation in how we tested these products on the bench,” Prabhu said.
“We tried to simulate the anatomy. We take the actual patient scans and develop these models. We look for those clinically, worst-case situations where we can test these products.”
A large amount of data from the original Portico delivery system also informed the FlexNav system, which Prabhu thinks could someday go into delivery systems for transcatheter mitral and tricuspid valves. Luckily, the manufacturing technology for catheters has evolved enough over the past 10 to 15 years that it was possible to achieve the smaller, tighter tolerances and other enabling technologies needed to make the improvements a reality.
“We are very committed to this space,” Prabhu said. “There will be more to come.”
