Complex transcatheter cardiac procedures, such as valve replacements, are often difficult to prepare for. Small anatomical differences can make big impacts on outcomes. Clinicians and researchers have been using models, both virtual and 3D printed, to improve procedural outcomes, design new devices, and to invent new therapeutic techniques. These models generally help professionals to understand nuances between patients, but they don’t reproduce the exact shapes and dynamics of moving tissues and structures.
Now researchers at the University of Minnesota, with help from Medtronic, have developed a way of 3D printing mimics of aortic heart valves and nearby anatomy which are so perfect that they reportedly look and feel just like the real things. These structures are actually printed based on CT scans of actual patients, so they nearly perfectly resemble the shapes of the tissues they are made to copy.
During the printing process, these models of aortic root structures, which include the valves and moving leaflets, are embedded with 3D printed sensor arrays that can measure the pressure at various points in the model and help guide actual procedures, including choosing the right tools and their sizes in advance.
“Our goal with these 3D-printed models is to reduce medical risks and complications by providing patient-specific tools to help doctors understand the exact anatomical structure and mechanical properties of the specific patient’s heart,” said Michael McAlpine, a University of Minnesota mechanical engineering professor and senior researcher of the study appearing in Science Advances, in a press release. “Physicians can test and try the valve implants before the actual procedure. The models can also help patients better understand their own anatomy and the procedure itself.”
The new models are made using novel silicone-based inks that were developed to nearly exactly reproduce physical properties of heart, valve, and vessel tissues. These inks require special 3D printers, but the inks are versatile enough to be able to copy the softness of valve leaflets with attached calcifications at the same time.
“As our 3D-printing techniques continue to improve and we discover new ways to integrate electronics to mimic organ function, the models themselves may be used as artificial replacement organs,” added McAlpine. “Someday maybe these ‘bionic’ organs can be as good as or better than their biological counterparts.”
Here’s a video showing the valve printing process and the new valves being tested under life-like conditions:
Study in Science Advances: 3D printed patient-specific aortic root models with internal sensors for minimally invasive applications