For the Aymara, weaving is a long-standing tradition deeply embedded in their culture. For children with heart defects, this weaving is life-saving. At a very young age, Aymara women learn this technique – making the skilled weavers’ steady hands the perfect solution to creating a small high-tech medical product that can’t be mass produced. Using a single strand of nitinol – an elastic metal – the Aymara women carefully weave the top-hat shaped occluder meant to close the hole in a patient’s heart, according to the BBC. Machines typically make occluders.

The implant – created by Bolivian cardiologist Franz Freudenthal – travels through blood vessels and expands when it reaches the heart. Though Aymara women have spent a lifetime perfecting their weaving techniques, they train for four months in a lab, according to AJ+. The delicate occluders then work for the person’s entire life. “We are very happy, we are doing something for someone so they can live,” Daniela Mendoza said.

AJ+

Freudenthal explains that because of the high altitude level – 13,000 feet above sea level – it’s more difficult for those with congenital heart issues. He set up shop in La Paz, Bolivia to provide a minimally invasive procedure. It’s especially crucial in a country that lacks cardiac doctors. The BBC explains that this method is also culturally necessary. Some indigenous communities believe that open-heart surgery – or any manipulation of the heart – tarnishes the human soul.

40 Aymara women create 250 to 300 devices monthly, and it’s a source of pride for the women. “I learned how to weave when I was a child,” said Julia Yapita Poma. “They teach us in the schools, and our mothers tell us we must learn how to weave. I never imagined I would work like this, saving people, saving kids. For me, it a blessing that fell upon me to work here. I feel proud.”

Freudenthal’s company, PFM SRL, has sold 7,000 implants to patients in Latin America, the Middle East, and Europe. And it hopes to eventually donate one implant for each one sold.

Check them out in action below: