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3-D printed custom silicon heart valves


Custom silicon heart valves

Multi-material additive fabrication of patient-specific shaped heart valves. Elastomeric printing makes mechanical matching possible with the biological tissue of a host. Credit: Fergal Coulter / ETH Zurich

Scientists at ETH Zurich and the South African company Strait Access Technologies use 3-D prints to produce custom synthetic heart valves from silicon. This can help to meet a growing demand from a population after replacing heart valves.

The human heart has four chambers, each equipped with a fentil to ensure only blood flow in one direction. If one of the heart valves is leaking, restricted or divided (or even breaks), the blood runs back into & # 39; the atria or the ventricles, which puts the whole heart under severe tension. In the least, this can lead to arrhythmia or even heart failure.

Depending on & # 39; a defect, artificial valves can be inserted to repair the problem. In & # 39; the next few decades, the demand for this type will likely occur in many parts of & # 39; the world is changing because of the wastage of people, lack of physical exercise and poor diet. It is estimated that by 2050, about 850,000 people will require artificial heart valves.

Researchers working at ETH Zurich and the South African company SAT have therefore been looking for an alternative to the replacement heart valves that are currently & # 39; And with some success: they have created an artificial heart valve made of silicon, which is made in several steps with 3-D printers. Scientists have reported on their work in an article in the latest issue of the scientific journal "Matter."

The new model has several advantages over conventional heart valves: the silicone heart valve can be more precisely adapted for the patient, first determining the individual's shape and size of a leaky heart valve with computer tomography and magnetic resonance imaging. This makes it possible to print a heart valve that perfectly matches the heart rate of a patient. The researchers use the images to create a digital model and a computer simulation to calculate the forces that work at the implant and the potential deformation thereof. The material used is also compatible with the human body, while the blood flow through the artificial heart valve is as good as with conventional replacement valves.

Chronic surgeons have traditionally used implants that consist of hard polymers such as animal tissue (from cows or pods) combined with metal frames. To prevent the body from rejecting these implants, patients need to take lifelong immunosuppressants or anticoagulants, which have no significant unwanted side effects.

Easier to make

In addition, conventional replacement valves have a very rigid geometric shape, making it challenging for surgeons to provide a tight seal between the new valves and the heart tissue. "The currently used replacement valves are round, but do not exactly match the shape of an aortic, which is different for each patient," says Manuel Schaffner, one of & # 39; a chief author of the study and former doctoral student of André Studart, professor of complex materials at ETH. In addition, making artificial heart valves is both expensive and timeless.

Credit: Fergal Coulter / complex materials / ETH Zurich

The new type of silicone valves comes around this problem. It takes only hour for researchers to produce a valve with a 3-D printer. In contrast, it takes several business days to make an artificial heart valve with the help of bovine material. Production with 3-D printers could also be faster: for example, a battery of printers could produce dozens or even hundreds of valves every day.

First, the scientists make a negative impression of "". Silicone ink is sprayed on this impression in the form of a three-point crown, which is the thin flaps of & # 39; a fentyl form. In the next step, an extruder printer deposits tough silicone paste to print specific thin-patterned patterns on their surface. These correspond to collagen fibers passing through natural heart valves. The silicone threads reinforce the valve flap and extend the life of the replacement replacement. The root of the lipid connected to & # 39; the heart valve is printed with the same procedure and turns on & # 39; an end covered with a net-shaped stent, that is needed for connecting the silicone valve replacement to the & # 39; cardiovascular system; a patient.

Long service life

Initial tests have produced significant results for the function of the new fentil. The goal of the material scientists is to extend the life of these replacement valves to 10-15 years. This is how long current models take for patients before they have to be exchanged. "It would be great if we could produce one day heart valves that would last a whole lifetime and possibly grow together with the patient, so they could be implanted into young people," Schaffner says.

However, it will take at least 10 years for the new artificial heart valves to come into clinical use, because they must first go through extended clinical trials.

Fergal Coulter, lead author of & # 39; s study, is currently working on & # 39; The further development of a silicone heart valve. "These experiments are needed to ensure that technology is in any case likely to be used in human patients," he says. Coulter is a postdoc in Professor Studart's group and needed the 3-D printers to produce heart valves.

New material is very robust

Coulter also experiments with new materials that can prolong the lives of heart valves.

Wool is an industrial partner, possibly needing a spin-off to commercially make the heart valve available on & # 39; brands. "As a research group, we are unfortunately unable to provide a seamless supply of the first experiment to the first application in the human body," Schaffner says.

FDA approves mechanical heart valve for patients

More information:
Fergal B. Coulter et al. Bio-inspiratory heart valve prosthesis made by silicone-induced production, Matter (2019). DOI: 10.1016 / j.matt.2019.05.013

3-D Printed Custom Silicon Heart Valves (2019, July 23)
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