3-D Printing Gets a Heart to Help
Improve Valve Replacement Procedures
December 28, 2016
Tens of thousands of patients each
year are diagnosed with heart valve disease, with many in need of
lifesaving surgery to treat the condition.
Now, researchers at the Georgia Tech Manufacturing Institute are working
on a tool that could help cardiologists care for patients with the
Using highly detailed imaging from CT scans, mechanical engineers are
using 3-D printers to make an exact model of an individual patient’s
heart valve. These one-of-a-kind models not only represent the size and
proportion of the heart valve but can also mimic its physiological
qualities — such as how it feels and responds to pressure.
The goal is to provide doctors with a new tool for planning procedures
to treat aortic stenosis, a condition in which the valves in the left
side of the heart narrow, restricting blood flow and potentially leading
to heart failure. The condition is commonly associated with elderly
patients, and its prevalence is thought to be on the rise as the
Wang, a postdoctoral researcher at Georgia Tech, and Zhen Qian, chief of
Cardiovascular Imaging Research at Piedmont Heart Institute, inspect a
printed heart valve.
The 3-D printed heart valve models are particularly useful in planning a
minimally invasive procedure called transcatheter aortic valve
replacement (TAVR), during which heart doctors use a catheter to deliver
a prosthetic heart valve to replace the patient’s impaired valve.
The procedure is a great option for patients who are at high risk for
complications with a standard open-heart valve replacement surgery. The
prosthetic valves are readily available in a range of types and sizes
from multiple manufacturers; however, one of the most important factors
for a positive outcome is matching up the patient’s natural heart valve
with a prosthetic of the right type and size. That’s where the 3-D model
comes into play.
“The issue is, everybody is different,” said Chuck Zhang, a professor in
the Stewart School of Industrial and Systems Engineering. “A male will
be different than a female. It’s a big challenge for the doctors to
select the right type of that prosthesis for a specific patient.”
Creating a custom model that moves, feels, and stretches similar to a
patient’s own valve can make picking the right valve much simpler, he
Zhen Qian, chief of Cardiovascular Imaging Research at Piedmont Heart
Institute, which has partnered with Georgia Tech researchers on the
project, said the 3-D printed models hold great promise for use in
preparing for heart procedures.
“The results are quite encouraging,” Qian said. “Our printed model is
able to tell you before the procedure how much paravalvular leakage
there will be and where it is, a good indicator for short- and long-term
Picking the right type and size and getting a good seal between the
prosthetic and the natural cardiac valve wall is key to preventing blood
leaking around the prosthetic. That’s where a personalized 3-D printed
model can help.
The models are created by a machine that is capable of multimaterial 3-D
printing. The researchers are able to adjust the design parameters —
such as diameter and curving wavelength — of the metamaterial used for
printing, which allows them to more closely mimic physiological
properties of the tissue.
For example, the models can recreate conditions such as calcium
deposition, which is a common underlying factor of aortic stenosis.
has been experimenting with embedding sensors on the models as well,
using a machine that can print nanomaterial-enabled circuitry on the
wall of the valve. The sensors could potentially be used to monitor how
much a prosthetic valve strains or deforms the model. With this sensing
capability, the printed heart valve also can be used as a phantom to
monitor pre-surgery practice.
So far, the researchers have printed almost two dozen heart valve models
based on actual patient imaging. They are now using images and data from
patients who have already undergone the procedure to better analyze how
well the models can predict the success of the prosthetics. The next
step will be to have the models printed before the procedure for
inclusion in the pre-surgery planning phase.
“There is big potential for these models,” Zhang said. “We’re thinking
in the future, this may be a standard tool for pre-surgery planning and
for training new surgeons.”