3D printing technology has allowed researchers to find most successful ways of boosting the success rate of aortic valve replacements. The models could enable doctors to predict how well a prosthetic heart valve will fit a patient, thus lessening the chance of paravalvular leakage – ‘blood flows through a channel between the implanted valve and cardiac tissue as a result of a lack of appropriate sealing’. Paravalvular leakage increases the risk of heart failure.
Transcatheter aortic valve replacement (TAVR) is a surgical procedure that replaces the damages aortic valve with a new replacement prosthetic aortic valve. This prosthetic valve is supposed to expand once inserted and work as efficiently as a normal aortic valve. However, due to the risk of paravalvular leakage it was realised that there is a need for a better and more successful way of predicting the fit of a prosthetic valve. As a result, study co-author Zhen Qian, chief of Cardiovascular Imaging Research at Piedmont Heart Institute in Atlanta, GA, and colleagues have developed 3-D heart valve models in order to simulate the heart valve tissue based on 18 patients who had TAVR. The team said:
“Our method of creating these models using metamaterial design and multi-material 3-D printing takes into account the mechanical behavior of the heart valves, mimicking the natural strain-stiffening behavior of soft tissues that comes from the interaction between elastin and collagen, two proteins found in heart valves.”
After this, medical imaging and computer software was used in addition to radiopaque beads that identify any problems with the fit of the heart-valve mimicking tissue. This created a bulge index which, in short, brought about this conclusion. The greater the bulge index score, the higher their severity of paravalvular leakage. This method of testing severity of paravalvular leakage has been discovered to be more accurate that using levels of calcium buildup on the damaged heart valve.
The researchers have said that this finding is very encouraging and could potentially transform care for patients who undergo TAVR.
“Even though this valve replacement procedure is quite mature, there are still cases where picking a different size prosthetic or different manufacturer could improve the outcome, and 3-D printing will be very helpful to determine which one,” — Zhen Qian
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