Researchers from the University of Minnesota,
with support from Medtronic, have developed
a groundbreaking process for multi-material
3D printing of lifelike models of the heart’s
aortic valve and the surrounding structures
that mimic the exact look and feel of a real
patient.
These patient-specific organ models, which
include 3D-printed soft sensor arrays integrated
into the structure, are fabricated using specialized
inks and a customized 3D printing process.
Such models can be used in preparation for
minimally invasive procedures to improve outcomes
in thousands of patients worldwide.
The research is published in Science Advances,
a peer-reviewed scientific journal published
by the American Association for the Advancement
of Science (AAAS).
The researchers 3D printed what is called
the aortic root, the section of the aorta
closest to and attached to the heart.
The aortic root consists of the aortic valve
and the openings for the coronary arteries.
The aortic valve has three flaps, called leaflets,
surrounded by a fibrous ring.
The model also included part of the left ventricle
muscle and the ascending aorta.
This organ model was specifically designed
to help doctors prepare for a procedure called
a Transcatheter Aortic Valve Replacement (TAVR)
in which a new valve is placed inside the
patient’s native aortic valve.
The procedure is used to treat a condition
called aortic stenosis that occurs when the
heart’s aortic valve narrows and prevents
the valve from opening fully, which reduces
or blocks blood flow from the heart into the
main artery.
Aortic stenosis is one of the most common
cardiovascular conditions in the elderly and
affects about 2.7 million adults over the
age of 75 in North America.
The TAVR procedure is less invasive than open
heart surgery to repair the damaged valve.
The aortic root models are made by using CT
scans of the patient to match the exact shape.
They are then 3D printed using specialized
silicone-based inks that mechanically match
the feel of real heart tissue the researchers
obtained from the University of Minnesota’s
Visible Heart Laboratories.
Commercial printers currently on the market
can 3D print the shape, but use inks that
are often too rigid to match the softness
of real heart tissue.
On the flip side, the specialized 3D printers
at the University of Minnesota were able to
mimic both the soft tissue components of the
model, as well as the hard calcification on
the valve flaps by printing an ink similar
to spackling paste used in construction to
repair drywall and plaster.
Physicians can use the models to determine
the size and placement of the valve device
during the procedure.
Integrated sensors that are 3D printed within
the model give physicians the electronic pressure
feedback that can be used to guide and optimize
the selection and positioning of the valve
within the patient’s anatomy.
As the 3D-printing techniques continue to
improve and the researchers discover new ways
to integrate electronics to mimic organ function,
the models themselves may be used as artificial
replacement organs in the future.
