Capstan Medical CEO Maggie Nixon offers a tech update from the structural heart robotics startup

Capstan Medical is closing in on some major milestones as it develops its structural heart surgical robot platform and catheter-delivered cardiac implants for mitral and tricuspid valve replacement.

The startup announced a $110 million Series C funding round with support from investors including Intuitive Ventures, and plans for some high-level hires as it pushes toward its first-in-human procedure.

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Ahead of that announcement, Capstan Medical CEO Maggie Nixon offered a technical update in an interview with Medical Design & Outsourcing to bring us up to speed on what she and her team have been up to since we last spoke in spring 2024. (The following has been lightly edited for clarity and length.)

MDO: What more can you share about your mitral valve, the robot, and the tricuspid valve? Last time we spoke you were in verification and validation (V&V) on mitral, right?

Nixon: “We’re doing final production of our first-in-human. We’re on the back end of that V&V wave. We’ve got our our robotic architecture set up, our catheter range of motion, and all of that is really been enabling on accessing the locations in the heart that we need to get to optimize the position of our implant. What’s exciting is we’ve been really starting to make it a little easier to use for the clinicians. This is where we’re starting to look at preoperative CT images and map pathways and leverage that technology to navigate into position, make it easier for clinicians to navigate through those pathways. So we’ve got some new coordinated motion control activity that we’ve been able to implement on the control side. And rather than just having pure button presses to move the individual joints, we’ve got coordinated algorithms around that right now. With that, we’re going to be learning so much as we get multiple clinicians with their hands on the devices. We had our clinical advisory board in the last three months pressure testing everything that we’ve implemented, and that’s already fueling what the next-gen device is going to look like. So this first-in-human configuration, we’re locked in on, but this is when all of these different control modes are going to start feeding what our actual user interface needs to look like for this next-gen that will go into the pre-pivotal and pivotal activities? This is where we move away from an Xbox controller into our custom controller based on how you know this user feedback is being leveraged into these control modes. We’ve got that foundational architecture. We know how our device can articulate from point A to point B, and now we get to do some of the smart under-the-hood features to make it user friendly.”

MDO: What’s your biggest challenge there?

Nixon: “We’re going to learn what’s most beneficial to the user in these coming months, and that’s where we are going to need to aggregate all those different perspectives because there’s not going to be a unified [perspective]. We could do all these different things, and we’re going to take that and streamline it into what we think is the optimized pathway. It is interesting. A lot of these users are very used to manual catheters and the restrictions around manual catheters. So sometimes, when we’ve been giving a feature to a user, they’re just leveraging that innate experience, but you can do different things. There’s no way they’ve had an opportunity to experience those alternative methods of interfacing with the device, so sometimes it’s putting multiple things in front of these users, and you have to give them some time to absorb it because it looks totally different than what they’ve seen in the past. That’s going to be the challenge, aggregating all of those really diverse perspectives into a unified approach. The other thing is imaging integration. As we learn more, how much is valuable, and what do we want to do to optimize leveraging the echo and fluoro imaging into the device? Those are going to be some of the biggest challenges.”

MDO: Have you got any technical updates on the tricuspid project?

Nixon: “The excellent thing about tricuspid is there’s so much focus on the tricuspid valve in the structural heart space right now. You’ve seen the TriClip and the Evoque products come into market, and with that, you get all that additional insight. So we’ve made some adjustments into the size of our implant that we’re starting with. We’ve made some adjustments to the geometry and how it collapses down, and we’re moving into the pre-clinical work, the chronic animal implants; we’ve integrated it into our catheter and are moving through our acute animal studies with the device. This will continue all the way through the first half of next year and then move into formal V&V to start those first-in-human cases.”

MDO: The change to the size — are you making the heart valve smaller?

Nixon: “With a lot of these clinical studies that are coming out right now, we’re getting some insights on the size of the tricuspid valve, and it’s on a curve — sometimes it’s on the smaller end, and sometimes on the bigger end. When we’ve been looking at these patients, we’ve been seeing that their annulus has expanded more than we originally thought. We had picked the nominal size, so we wanted to get that size a little bit bigger, trying to hit the midpoint of that curve for our first size. All of these implants typically need multiple sizes to address that full curve of patients, and so we upped it a little bit to try to hit that midpoint as closely as possible.”

MDO: And that size increase doesn’t change the size of your delivery catheter, right?

Nixon: “No, it’s the size of the frame. It still collapses down to the same size.”

MDO: What about the change in geometry, can you explain that more?

Nixon: “The left side of the heart with the mitral valve and the right side of the heart with the tricuspid valve are really different. First and foremost, the pressures are really different. In the tricuspid valve, the pressures are a lot lower so you don’t need the same rigidity and retention structure around it. That gives you some flexibility to navigate a few different geometries on that front. And so we’re still trying to stay compatible with a variety of anatomies, but we’re doing that by keeping our implant nice and compliant so it can conform to the existing anatomy. You can do that a little bit easier on the right side of the heart, just because of those lower pressures. You don’t have the retention kind of demands that you do on the left side of the heart.”

MDO: And you’re getting that compliance from the nitinol frame?

Nixon: “Yep, we use self-expanding nitinol for both of our implants.”

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MDO: Are you developing a single robot for both of the heart valve implants?

Nixon: “It is the same robotic platform. We’ve got a modular robotic platform where you can put different catheter instruments onto that platform. The back-end interface on the catheter is the same on the robotic platform. The articulation for the tricuspid is different. For the mitral, you’re coming in the right side of the heart, crossing the septum and moving into the left side of the heart. For the tricuspid, you don’t have to cross the septum, you’re just moving down into the tricuspid, so it puts different range of motion requirements onto that catheter. Each of those catheters has a unique set of specifications in order to navigate into that specific area of the heart.”

Read more from this interview about Capstan Medical’s Series C funding round and project timelines at MassDevice.