From minimally invasive catheterization delivery to wireless power charging to overall miniaturization, the cardiovascular device field has seen plenty of advances in recent years.
Karen May-Newman, PhD, has been in the thick of it as the director of the bioengineering program at San Diego State University, where she designs and runs transparent heart simulators that game out how left ventricular assist devices (LVADs) are changing the flow of blood through the heart and its valves.
MPMN recently caught up with May-Newman to discuss some of the innovations, enabling technologies and design challenges in the cardiovascular space:
MPMN: What do you presently find most exciting in the cardiovascular device field?
May-Newman: I think minimally invasive catheterization delivery methods are really exciting. They're a huge challenge, though. I don't think we've quite mastered that method of delivery, but I do think that's something I'm looking at--seeing the [Edwards Lifesciences] Sapien heart valves come out, and other catheter-based methods that have replaced open heart surgery. But they haven't been perfected yet, and I'm looking forward to development of that.
Also, an area that is very exciting that is still very early is wireless power delivery. There are some systems in development right now that will allow people to free themselves of tethers to high-powered implanted devices like ventricular assist devices, which I work on. That will allow them to at least move around a properly instrumented room, instead of having to be always tethered through a port through their skin to some power source. The skin ports ... have a tendency to get infected. So if you can eliminate any kind of opening through the skin into the body to provide the device with power, then you've really eliminated a huge percentage of the adverse events that arise with these devices.
MPMN: You mentioned issues with catheterization. What are some examples of the challenges?
May-Newman: Fixture placement, both in terms of alignment and orientation as well as the actual fixation to the tissue, are less well controlled than when you have an open heart surgery. The cardiac surgeons are extremely deft and precise with their stitching. They know exactly the orientation. They can feel with their hands what the forces are and adjust the tension in their sutures. ... You don't really have the same type of tactile feedback when you're placing something with a catheter. You also don't have, at least not yet, the ability to stitch precisely like you do when you actually have your fingers in there. ...
It's like remote control, versus being there yourself. You're relying on something else as an intermediate to give you feedback. It doesn't capture all of the same information that your fingers and your eyes do.
A driving force to the catheter-based systems is that it's much less traumatic surgery for the patient, which translates into lower costs, both with the physicians time and the hospitalization. The push is coming from that direction. ... But it is still an early area. Like with all things that are complex it goes through multiple iterations. I think we're kind of on the front end of the evolution. It's going to take a few more iterations of devices to find out what the problems are, fix them in the next generation.
MPMN: What role are you playing in this?
May-Newman: To the extent that things like simulations and animal studies can be used to flesh out these problems before they are implanted in humans, that's kind of what I see ... people like me in the medical device industry doing. ...
You're trying to anticipate what the problems there will be, and design a strategy early on the process so that you don't have to find out through some bad experience what is not working. You can take care of the bad experiences through computational models or emulations or strategic animal studies. ...
MPMN: What is your preffered method for testing out heart devices?
May-Newman: I probably rely less on computational studies than experimental studies. What I do is set up a mock system in my lab that has a device in it and a cardiac simulator that is all transparent. And then I use video-based equipment in order to do particle tracking in order to look at flow as well as the displacement of valves and other things that are solid and moving inside of that system.
To some degree, it is harder to replicate the physics in a computational environment than you might think. We all think computer models can do anything, but because they can do anything they will do anything.
MPMN: We have notices many recent stories about cardiovascular device advances that seem to be enabled my electronics miniaturization. There are tiny leadless pacemakers that can be implanted via a catheter inside the heart. There's the potential for bloodstream nanosensors that could provide early warning of a heart attack. There is the potential for flexible electronics that could literally wrap around a heart.
What is allowing all of this miniaturization to happen? Why is it happening now?
May-Newman: [It is] taking advantage of all of the technology that's been developed for wireless communication and computers, in terms of making things really small, making smart microprocessors and things that allow people to be more mobile.
[You can have] a lot more smart controls on the devices that have been around for a while, pacemakers and defibrillators, obviously insulin pumps and glucose measurement systems. These are all things that have kind of harnessed what was developed for other industries, in my opinion.
A big push, of course, is to try to reduce healthcare costs. Anything that lowers the cost of surgery, lowers the cost of hospitalization, is driving as many of these innovations as miniaturization. The two kind of go hand in hand anyway, because the smaller the cut you can make in somebody, the faster they should heal, the lower the complication rate, etc.
The challenge is to do all these things, but maintain a level of safety. ... It's not always easier to replace something expensive with something less expensive and keep the same level of safety.
I think the FDA really has some challenges to understand how to test these devices and make sure they're safe for the long term.
MPMN: What else is enabling the advances?
May-Newman: The other thing is there are really some amazing fabrication processes for making components that you couldn't easily machine in the past. The MEMS [Micro-Electro-Mechanical Systems], which is sort of an outgrowth of the semiconductor industry, allows you to fabricate extremely small components at a high level of precisions that are really complicated. And it's really cheap.
Also, there's 3-D printing ... people using 3-D printing to directly print implants that are then placed in people. ... That would allow people to potentially customize things with personalized medicine, but keep it at a reduced cost.
MPMN: But cost is a major driver?
May-Newman: I think cost is always this underlying push behind these technologies that become successful.