Researchers have created a technique to 3D-print custom, actuated replicas of human hearts to help guide treatment decisions for patients with heart disease and other cardiac afflictions. A team of engineers at MIT developed the procedure, which turns 3D models of individual patient hearts into a soft, robotic version that can replicate how the organ actually works, making it an artificial facsimile of the real thing, they said. The aim for the 3D-printed heart replicas—which can be controlled to mimic a patient's ability to pump blood—is to help doctors tailor treatments to patients’ specific heart form and function, said Luca Rosalia, a graduate student in the MIT-Harvard Program in Health Sciences and Technology.
“All hearts are different,” he said. “There are massive variations, especially when patients are sick. The advantage of our system is that we can recreate not just the form of a patient’s heart, but also its function in both physiology and disease.”
Further, researchers can use the technology to print a custom patient aorta—the major artery that carries blood out of the heart to the rest of the body—and inflate a separate sleeve surrounding the artificial artery to constrict the vessel to mimic aortic stenosis, a form of heart disease.
This simulation can help doctors apply common surgical treatments first on the model heart before performing actual surgery, helping them test new therapies and boost levels of success in treating patients, researchers said.
History of 3D-Printed Heart Replicas
Researchers have been working on the project since before the COVID-19 pandemic when they developed a "bionic" heart—a general replica of a heart made from synthetic muscle containing small, inflatable cylinders that could mimic the contractions of a beating heart—in the lab of MIT Professor Ellen Roche. They used these cylinders to control the replica to mimic the contractions of a real beating heart.
In March, when the lab shut down temporarily, Rosalia continued to work on the design in his dorm room so that when the lab reopened some months later, researchers began testing the design in animals as well as using computational models. They then expanded their approach to develop sleeves and heart replicas that are specific to individual patients, which led them to turn to 3D printing to achieve their goals.
Researchers used polymer-based ink that—once printed and cured—could squeeze and stretch to produce custom replicas of actual patients' hearts. They created 3D models of the hearts for printing using medical scans of 15 patients diagnosed with aortic stenosis, researchers said.
The resulting prints were soft, anatomically accurate shells of both the heart ventricle and vessel, they said. Researchers also fabricated tailored sleeves to wrap around the printed forms and connect to a small air pumping system so they could realistically contract and constrict the printed models like an actual heart pumps blood, Roche said.
“Being able to match the patients’ flows and pressures was very encouraging,” she said. “We’re not only printing the heart’s anatomy, but also replicating its mechanics and physiology. That’s the part that we get excited about.”
Testing Real-Life Treatments Thanks to the 3D-Printed Heart Replicas
Researchers even replicated some of the medical interventions that some of the patients already underwent to see whether their printed hearts had a similar response. What they observed in some cases is that the implanted valve produced similarly improved flows in the robotic hearts as in actual patients following their surgical implants, they said.
The team also used a printed robotic heart to compare implants of different sizes, to see which would result in the best fit and flow for the patient. They hope that one day medical professionals will use the heart replicas in this manner to devise the best treatment solutions for patients, they said.
Researchers published a paper on their work in the journal Science Robotics. Ultimately, they believe the technology can be especially useful for identifying treatments for patients with unique and/or challenging cardiac anatomies that may have specific needs that deviate from mainstream treatments, Roche said.
“Designing inclusively for a large range of anatomies, and testing interventions across this range, may increase the addressable target population for minimally invasive procedures,” she said.