Researchers at Michigan State University have created a miniature human heart model in the laboratory for the first time. The model has all the major cardiomyocytes, chambers and vascular tissues necessary for the normal functioning of the heart.

Cardiovascular disease (CVD) is the leading cause of morbidity and death for all people in the world, accounting for about one-third of all deaths.

       3D printing technology has evolved by leaps and bounds in recent years, rising to a new level in a matter of months.


　　In a new study recently published in Science Advances, researchers from the University of Minnesota, supported by Medtronic, have developed a groundbreaking technique to 3D print realistic models of the heart's aortic valve and surrounding structures in multi-materials that mimic the look and feel of a real patient.

 




　　These patient-specific organ models, including 3D printed soft sensor arrays integrated into the structure, are manufactured using specialised inks and a bespoke 3D printing process. Such models can be used in preparation for minimally invasive surgery, and it will improve the prognosis for thousands of patients worldwide.


　　The researchers 3D printed the aortic root, the part of the aorta closest to and connected to the heart, consisting of the aortic valve and coronary opening with three valves, called leaflets, surrounded by a fibrous ring. The model also includes the left ventricular muscle and part of the ascending aorta.


　　

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 anatomy and mechanical properties of a particular patient's heart," said Michael McAlpine, corresponding author of the study and professor of mechanical engineering at the University of Minnesota. Doctors can test and trial valve implants before actually performing them. These models can also help patients better understand the anatomy of their own heart and the procedure itself."


　　This organ model is primarily used to help doctors prepare for transcatheter aortic valve replacement (TAVR), which places a new valve into the patient's own aortic valve. This procedure is used to treat aortic stenosis, one of the most common cardiovascular conditions in the elderly population. the TAVR procedure is less invasive than direct heart surgery to repair a damaged valve.


　　A model of the aortic root was made by taking a CT scan of the patient to match the exact shape. The model was then 3D printed by the researchers using a special silicon-based ink. The ink, from the University of Minnesota's Visual Heart Lab, was able to match the feel of real heart tissue. Current commercial printers on the market can 3D print shapes, but the inks used are often too hard to match the softness of real heart tissue.


　　On the other hand, a specialist 3D printer at the University of Minnesota was able to simulate the soft tissue component of the model, as well as the hard calcification on the flap, by printing an ink similar to the scattering paste used to repair drywall and plaster.


　　These models can be used by the surgeon to size and position the valve device during the procedure. The electronic pressure feedback provided to the surgeon by the 3D printed sensors integrated in the models can be used to guide and optimise the selection and positioning of the valve within the patient's anatomy.


　　But McAlpine does not see this as the end of the road for such 3D printed models.


　　McAlpine, Chair Professor of Mechanical Engineering at the University of Minnesota, said, "As our 3D printing technology continues to improve, we are discovering new ways to integrate electronic components to mimic organ function, and these models may themselves be used as artificial replacement organs. Perhaps one day these bionic organs will be just as good as biological organs, if not better."

Recently, the journal Science Bulletin (English version) published the research results of Professor Gu Dongfeng's team, a member of the Chinese Academy of Sciences and Vice President of Fu Wai Hospital, Chinese Academy of Medical Sciences, in a cover article online.