eugenesergeev - Fotolia
3D printing is currently being used to manufacture everything from scoliosis braces to orthotics. But researchers from the Piedmont Heart Institute have taken the technology a step further to create a 3D printed heart valve. The team is studying how 3D printing can be used in surgical pre-planning to help doctors determine the right size of a replacement heart valve and reduce the risks associated with an improperly fitting valve, such as stroke or heart attack.
Zhen Qian, chief of cardiovascular imaging research at the Piedmont Heart Institute, and Mike Gaisford, director of marketing for medical solutions at Stratasys, a 3D printer manufacturer, discuss the implications of 3D printing in surgery and the impact it can have on patient care.
How did your team decide to use imaging and 3D printing to model a patient's heart?
Zhen Qian: We take a CT image before the procedure, and we measure [the] anatomical size of the organ. Based on the size, we make a decision about which valve size we want to use on this specific patient.
Zhen Qianchief of cardiovascular imaging research, Piedmont Heart Institute
There are no guidelines that say which company we need to use for this particular patient. The decision is really made by the interventionist. They have their personal preference. ... But is that the real better choice for this patient? Nobody knows.
There are very natural decisions you can make because you have an image of the patient, you know the shape of the patient's organ. How do you virtually or on a desktop setting [place the valve] or do you really put the valve in? [You] do some testing before the procedure. 3D printing is a natural decision for us, so we wanted to try that out.
Mike Gaisford: [Piedmont] looked at some patients who had received valves. ... There's a method for sizing the valve and figuring out what size this patient needs. What they were able to do was compare the predictive performance of that method for determining the right valve with creating a 3D printed valve until you found the right fit. They discovered that by having the 3D printed heart valve, they were much more predictive in their abilities.
The implications on clinical care are significant because you don't want to place a valve on a patient, find out it's not the right size and have to remove it. That's both extensive and intrusive to the patient.
How does a 3D printed heart valve compare to an actual heart valve? Does it react the same way?
Qian: For now, there are many different printing techniques and incentives available, like the one from Stratasys; they have material techniques [where] they can print multiple materials in one model. In the model, you have different hardness or softness to mimic the heart tissue. ... When we have the ability to print different materials in one model, it will be more realistic.
Gaisford: What people were originally doing with 3D printing was [using] a single material 3D printer most often or entirely with pretty rigid material. More recently with multi-material printers, we're able to create different textures within a single print. So you're able to print soft tissue and hard bone, or print a tumor in a more rigid material or in a more colorful material.
The 3D printed model of the patient's heart valve doesn't need to last forever because it's just being used in a testing scenario where you're trying to determine what the appropriate therapy is. So they don't need to last for ages. There are certainly ways you could design it to last a lot longer if you chose different materials, but if you choose to use the softer tissues that are 3D printed, the softer plastics and rubberized materials, it's not going to last that long, but it's also going to be much more realistic in the way it simulates a beating heart and a valve opening and closing.
Has a 3D printed heart valve actually been used in a patient, or is it only being used in modeling?
Qian: All the experiments of the study were done in a retrospective fashion. We review previous patients who have already done the procedure, then we use the CT data to make the model. Then we make a prediction and see if the predictive result agrees with the patient result. We haven't done any prospective studies yet; it will involve more complexity.
VA partners with 3D printer manufacturer for surgical planning
3D printing blurs line between consumer and medical devices
3D printing comes with benefits and challenges