Patient-Specific Soft Robotic Heart Replicas for Treatment Planning

Researchers at MIT have developed soft robotic heart replicas that closely match the anatomy of real people. The researchers used medical images of patient hearts to construct computer models that are suitable for 3D printing. Once printed with a soft material, the patient-specific heart models can be actuated using external inflatable sleeves, in the style of blood pressure cuffs, allowing the team to match the blood flow and pressure parameters parameters of the original heart. These models allow clinicians to accurately model cardiac anatomy, physiology, and mechanics for an individual patient, and test the effects of various therapeutic interventions on these parameters. So far, the researchers have shown that the constructs can accurately model aortic stenosis and therapeutic interventions, including aortic valve placement to widen the aorta.

While gross anatomy is somewhat of a fossilized discipline, with the major structures inside our bodies having long been described and cataloged, our anatomy can still vary wildly from person to person. We can embrace this diversity, but it can be a headache for clinicians who need to design treatments for patients, including those who treat heart conditions. These issues have inspired these MIT researchers to develop a way to model an individual’s heart and then use the model to figure out the best treatment, based on its unique anatomy.

“All hearts are different,” says Luca Rosalia, a researcher involved in the study. “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.”

The method begins with a medical scan of a patient heart, which is then converted to a 3D computer model. The researchers can then 3D print this model using a polymer ink that results in a soft and flexible construct that accurately matches the anatomy of the patient. The models can also include nearby blood vessels, such as the aorta, allowing clinicians to model aortic disease.

Then, the researchers add inflatable sleeves to the model that allow them to actuate it very precisely. This can also include adding a sleeve to constrict the printed aorta to mimic aortic stenosis. When fluid is added to the system, the model can pump it and with a little fine-tuning, the researchers can actually match the blood flow and pressure parameters of the original patient.

The researchers hope that the technique will allow clinicians to optimize interventions before they begin. For instance, they could try fitting various synthetic aortic valves to find the one that fits best and has the most beneficial outcome.

“Being able to match the patients’ flows and pressures was very encouraging,” said Ellen Roche, another researcher involved in the study. “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.”

See an MIT video about the project: