How 3D printing is improving heart surgery

I’ve written a few times recently about the growing role 3D printing is playing in healthcare, whether it’s in reducing the need for animal testing, producing better medical implants or helping surgeons to prepare for operations.

A recent paper highlights how 3D printing could help cariologists prepare for life-saving heart valve replacements by giving them realistic heart valve models to work from.

The researchers used medical imaging and 3D printing to perfect replicas of each patient’s heart valve, with the aim being to improve the success rate of transcatheter aortic valve replacements (TAVR) by reducing a complication known as paravalvular leakage.

“Paravalvular leakage is an extremely important indicator in how well the patient will do long term with their new valve,” the researchers say. “The idea was, now that we can make a patient-specific model with this tissue-mimicking 3D-printing technology, we can test how the prosthetic valves interact with the 3D-printed models to learn whether we can predict leakage.”

Predicting behavior

The researchers found that the 3D printed models were so effective at replicating real hearts that they could be relied upon to predict such leakages reliably, and therefore having a big impact on patient care.

The models are created using metamaterial designs and a multi-material 3D printer.  This affords them control over the design to allow a close replica of the physiological properties of the tissue.

“Previous methods of using 3D printers and a single material to create human organ models were limited to the physiological properties of the material used,” the researchers say. “Our method of creating these models using metamaterial design and multi-material 3D printing takes into account the mechanical behavior of the heart valves, mimicking the natural strain-stiffening behavior of soft tissues that comes from the interaction between elastin and collagen, two proteins found in heart valves.”

The models were created from medical imaging of 18 patients who had undergone valve replacement surgery.  The models were fitted with radiopaque beads to help them measure the displacement of the tissue-mimicking material.

These models were then paired with the same size and type of prosthetic valves used by cardiologists during the actual operations.  The prosthetics were inserted inside the models to ensure the new valves were located in exactly the right place.  Software was then used to analyze medical imaging to show the location of the radiopaque beads to show how the prosthetics were interacting with the 3D printed models.

“The results of this study are quite encouraging,” the team say. “Even though this valve replacement procedure is quite mature, there are still cases where picking a different size prosthetic or different manufacturer could improve the outcome, and 3D printing will be very helpful to determine which one.”

The next step is to continue working on the metamaterial design and 3D printing process, with further evaluation done to assess the use of the valves as a pre-surgery planning tool.  It will also be tested on a larger number of patient-specific models to improve the analytic tools further.

“Eventually, once a patient has a CT scan, we could create a model, try different kinds of valves in there, and tell the physician which one might work best,” they conclude. “We could even predict that a patient would probably have moderate paravalvular leakage, but a balloon dilatation will solve it.”

It’s a fascinating application of the technology, and you can learn more via the video below.

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