Breaking Barriers in Children’s Heart Health Research

Photo © SickKids

By Jasmine Budak, SickKids Foundation

In 2009, The Hospital for Sick Children (SickKids) in Toronto, Canada got its first 3D printer, large and clunky by today’s standards, but high-end at the time. Few were more excited than Dr. Shi-Joon Yoo, a cardiac radiologist who saw the technology’s enormous potential to help surgeons study their patients’ hearts. With little more than a user’s manual, Dr. Yoo taught himself how to use the printer in his spare time. In those days, printing materials were rigid; the hearts were ceramic-like—and beautiful, Dr. Yoo recalls. But they also conveyed a lot of information, offering surgeons an exceptional view of the organ. They could hold it in their hand, see every angle, every valve, every unique defect. They would go into surgery with a better idea of what they’d find inside their patients.

Congenital heart surgeries are among the most challenging. Unlike adult cardiac patients whose heart anatomy is predictable, an infant’s congenital malformation can be completely unique and totally wonky. Main arteries could be reversed, or a whole chamber missing. Not to mention, newborn hearts can be as small as a strawberry.

By 2013, printer innovation had taken off. The machines were smaller and more precise, the materials softer and more pliable. Too eager to wait on funding, Dr. Yoo bought his own printer, set it up in a rented office space across the street from SickKids, and started printing hearts for his colleagues. These new models were flexible. They could be cut and sutured. They allowed surgeons an unprecedented opportunity to practice a rare or complex procedure beforehand. The potential benefits were enormous and exciting: fewer surprises in the operating room, reduced chance for error, and, ultimately, patients would fare better.

The practice proved so useful among SickKids surgeons, Dr. Yoo teamed up with Dr. Glen Van Arsdell, then-head of cardiovascular surgery at SickKids, to develop a training course so surgeons elsewhere could benefit. In 2015, Hands-On Surgical Training (HOST) launched: two four-day sessions welcoming a dozen surgeons from around the world.

Learning on models in a low-pressure environment where mistakes are not catastrophic will considerably fast-track a surgeon’s expertise, says Dr. Van Arsdell, now head of congenital cardiovascular surgery at UCLA Medical Center. (He remains a HOST instructor.) “I learned to operate over the course of 14 years. It’s a graded process; you are involved in progressively complex operations and expand your confidence bit by bit until you’re ready.” Training on models will practically obliterate this timeline. “For a mature surgeon, performing a complex operation three times on a heart model will be enough,” says Dr. Van Arsdell.

Over the years, the uptake has been growing. This past winter, amid COVID-19 global lockdowns and travel restrictions, the 6th annual HOST was held virtually for the first time. Hundreds of model hearts were printed, boxed, and mailed to 42 participants on nearly every continent. In some cases, trainees might be one of only two congenital heart surgeons in their country, where there are no teaching hospitals. For these surgeons, the opportunity to get more experience in rare disorders and learn from giants in the field is priceless and, broadly, could help improve pediatric heart-patient outcomes around the world.

Recently, HOST expanded to offer a year-long curriculum for surgeons-in-training, who’ve spent almost no time in the OR—people like Dr. Nabil Hussein, a cardiac fellow from the UK who felt compelled to come to SickKids after stumbling on a YouTube video about HOST. Dr. Hussein had been pondering his own long path as a new surgeon; he figured he’d be in his 50s by the time he was sufficiently trained in difficult procedures. “I wanted to help make this path better—shorter,” he says. He was convinced that learning on models was the way to do it, and he wanted to be part of the revolution. While at SickKids, Dr. Hussein helped establish HOST’s new curriculum and, later, was part of the team that devised an objective assessment tool to validate HOST’s results. “No one else is doing this in the world,” he says. “The biggest barrier is cost, and we would not have been able to do this without donors.”

HOST’s earliest supporters are Peter and Fabiola Butler. Peter’s connection with SickKids runs deep; in 1969, he had his first surgery to repair a congenital heart defect. He, more than most, appreciates the training and skill required by pediatric cardiac surgeons. Other key donors, Penny and Joseph del Moral, have a nine-year-old son who had several surgeries as an infant to correct his many heart defects. They too acutely understand the high stakes of congenital heart surgery and the value of 3D printing to improve patient outcomes—here and around the world.

For the HOST team, this world-first training program has proved its value and is here to stay. In several recently published studies, Dr. Hussein and HOST instructors showed that training on realistic models is highly effective. Using an objective assessment method, they found that for certain complex procedures, 80-87 percent of surgeons were more accurate, and all scored faster after practicing just once. And as 3D-printing technology advances and model hearts only get truer to life, their use in surgical training may very well become required curriculum in the field.

The Labatt Family Heart Centre at SickKids is one of the top pediatric centers in the world, uniquely structured so that clinicians and scientists work together to treat and solve some of the most severe pediatric heart diseases. To learn more, visit

To learn more about HOST, visit:

To donate, visit:

Photos © SickKids

Global Heroes Logo Grey

Get your free copy of Global Heroes, jam-packed with positive news, straight in your inbox.

Your subscription could not be saved. Please try again.
Your subscription has been successful.

Global Heroes Podcast


Subscribe to our Newsletter and Access all issues of Global Heroes News straight in your inbox. 100% free, no purchase necessary, for life. Uplifting stories, highlighting the inspirational efforts of everyday people, celebrities, and organizations, who are diligently working together towards practical solutions to global problems.