3D Printed Heart Valves - Dream Health

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Wednesday, 30 January 2019

3D Printed Heart Valves

3D printed heart valves enables an exact fit and ensures much lesser leaky valves.

According to statistics, there are more than one out of eight people above the age of 75 years in the US that develop a blockage of the aortic valve present in the heart. These blocks could be moderate to severe and the cause is due to calcified deposits on the valve’s leaflets. With the result the valves do not function well thus preventing them from opening or closing fully.

Since the elderly are not in a position to undergo open-heart surgeries, they undergo a procedure called transcatheter aortic valve replacement (TAVR), where the artificial valves are implanted in the heart. In this procedure, the valve is inserted into the aorta via a catheter.

While performing this TAVR procedure, the main challenge is choosing the perfect size valve without actually looking at the patient’s heart.Getting the exact replacement for the TAVR valves is a problem since the doctors cannot figure out if a particular valve will fit the patient’s anatomy before surgery. In the eventuality of the valve being small, there can be a leak around the edges or the valve can dislodge. In case the valve is big, then it can rip the heart and cause death.

Developing the 3D printed heart valves

To counter this, researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have created 3D printed heart valves. They have developed a 3D printing workflow whereby the cardiologists can figure out how the different valve sizes can adapt to a patient’s anatomy before the actual open-heart procedure is performed.

To obtain the 3D printed heart valves, they use CT scan data to obtain the physical model of each individual patient’s aortic valve. They also obtain a ‘sizer’ device to figure out the exact replacement of the valve.

With the 3D printed heart valves which includes the integrative 3D printing and valve sizing system, a customized data of each patient’s aortic valve is obtained. Hence there leaves no room for doubt and each patient can get the accurate sized valve.

Need for 3D printed heart valves 

When a patient required a replacement heart valve, a CT scan was needed. A series of X-ray images then creates 3D reconstruction of the patient’s anatomy. The calcified deposits are visible on the CT scan, but the leaflets of the valve are not clearly visible. After the 3D reconstruction of the heart valve is done there is not much information as to how the TAVR valve that had been inserted, would interact with the calcified deposits that are floating in the valve.

3D printed heart valves give an accurate fit and plugs leaks

Ahmed Hosny, a researcher at the Wyss Institute created a software program to create a 3D model of the leaflets by using seven coordinates on the patient’s valve that was seen on the CT scans. He then merged the digital leaflet model with the data from the CT scan and adjusted it to fit into the valve. The resulting model was 3D printed into a physical multimaterial model. They also printed a custom ‘sizer’ device to fit inside the valve model and expanded and contracted it to see which size would provide the best fit. The ‘sizer’ was wrapped with a pressure-sensing film to note the pressure between the ‘sizer’ and the 3D printed valves and their associated calcified deposits, slowly expanding the ‘sizer’.

They noted that the size and location of the calcified deposits on the leaflets play a significant role on how the artificial valve will fit into a calcified one.

The 3D printed heart valves with the multimaterial design which incorporates the flexible leaflets and the calcified deposits into an integrated shape, will mimic the behavior of the real heart valves.

Based on the 3D printed heart valves and the ‘sizer’ device, the researchers found that they could successfully predict the leaks in 60% to 73% of patients and 60% patients got the accurate size of the valve.

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