3D Print recently ran a piece concerning yet another medical application for additive manufacturing. In this case, 3D printing can “aid in a process called transcatheter aortic valve replacement, or TAVR.” This research was conducted by researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University.
Apparently, “more than one in eight people aged 75 and older in the United States develop moderate to severe blockage of the aortic valve, often caused by calcified deposits which build up on the valve’s leaflets and prevent them from fully opening and closing. Many of these patients are not healthy enough to undergo open heart surgery, so TAVR is an alternative involving the deployment of an artificial valve via a catheter inserted into the aorta.”
Of course, cardiologists must ensure the valve is the precise right size. If the valve isn’t the right size, the procedure could prove fatal for the patient. “It’s a challenge to select the correct size without directly examining the patient’s heart.” This is where 3D printing and the team from Harvard University come in.
These researchers “have come up with a 3D printing workflow which creates models of individual patients’ aortic valves using CT scan data, in addition to a ‘sizer’ device which helps cardiologists determine the proper valve size.”
As Dr. James Weaver, Senior Research Scientist at the Wyss Institute explains: “If you buy a pair of shoes online without trying them on first, there’s a good chance they’re not going to fit properly. Sizing replacement TAVR valves poses a similar problem, in that doctors don’t get the opportunity to evaluate how a specific valve size will fit with a patient’s anatomy before surgery. Our integrative 3D printing and valve sizing system provides a customized report of every patient’s unique aortic valve shape, removing a lot of the guesswork and helping each patient receive a more accurately sized valve.”
The researchers “created a software program which uses parametric modeling to generate virtual 3D models of the leaflets using seven coordinates on each patient’s valve that are visible on CT scans. The 3D models were then merged with the CT data and adjusted so they fit into the valve correctly. The resulting model, which incorporates the leaflets and their calcified deposits, was then 3D printed in multiple materials.”
“The system successfully predicted leak outcome in 60 to 73% of the patients, depending on the type of valve each patient had received, and determined 60% of the patients had received the correctly sized valve.”
Image and Quotes Courtesy of 3DPrint