Medicine-Engineering Collaboration Delivers World's Lightest and Smallest Pediatric Artificial Heart, Offering Hope to Children with Heart Failure

Our Staff Reporter Tian Doudou

Junjun, who has had an "artificial heart" implanted in his body for five months, came to Xiehe Hospital affiliated with Tongji Medical College of Huazhong University of Science and Technology in Wuhan for a follow-up examination. Blood tests, echocardiography... When a series of test results appeared on the computer screen, Professor Dong Nianguo, director of the Department of Cardiac and Great Vascular Surgery at Xiehe Hospital, smiled: "All indicators are relatively normal."

In March this year, 7-year-old Junjun successfully received the implantation of China's self-developed, lightest and smallest pediatric magnetic levitation "artificial heart" at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. At that time, Junjun was suffering from end-stage heart failure and had already experienced severe cardiogenic shock before the surgery. The only hope was a heart transplant. Compared to adults, pediatric heart donors are even scarcer. Before the implantation of the "artificial heart," Junjun’s life was hanging by a thread.

Such scenes, over the past 10 years, Dong Nianguo has witnessed quite a few. "Implanting a ventricular assist device can buy time for heart failure patients, but for children under 10 years old or weighing less than 30 kilograms, there were no magnetically levitated artificial hearts available globally until now," said Dong Nianguo.

In 2021, the Cardiac and Great Vascular Surgery team at Peking Union Medical College Hospital partnered with Shenzhen Core Medical Technology Co., Ltd. to launch a research and development project focused on magnetically levitated ventricular assist devices for young and low-weight pediatric patients.

"The pediatric version of the 'artificial heart' is not a proportional reduction of the adult version." Dong Nianguo said that the main technical difficulty of the pediatric version lies in shrinking the size while needing to increase the rotational speed to improve efficiency. However, increasing the speed not only causes self-generated heat but also easily leads to a series of problems such as blood clots. How can we achieve a small volume, large flow, high efficiency, and low power consumption?

In response to these issues, the engineers at Core Medical launched a series of research efforts. Breaking conventions, they developed the "time-sharing and zone-dividing axial full magnetic suspension control technology" and designed a highly integrated children's version of the "artificial heart." The pump structure is more simplified, the volume is smaller, and the built-in magnetic suspension motor achieves high efficiency and low power consumption, providing sufficient pumping capacity while reducing heat generation.

How to avoid the thrombosis risk caused by increasing rotational speed? The engineers optimized the blood flow path inside the pump to ensure a faster average flow rate, sufficient flushing, and shorter blood retention time, thereby minimizing the impact on blood.

The engineering goal has been initially achieved, but it still awaits practical verification. In May 2022, Core Medical’s key technical personnel delivered the first pediatric "artificial heart" prototype to Wuhan Union Hospital. Through multiple animal experiments, the hospital's cardiac and vascular surgery team identified a series of new issues and proposed many important suggestions from a clinical perspective based on pediatric anatomical features. Close communication between the medical and engineering teams, along with joint efforts to overcome challenges, led to dozens of iterative upgrades. Finally, the world's lightest and smallest pediatric version of the "artificial heart" was finalized, weighing only 45 grams—half the weight of the smallest adult version. Junjun became one of the first beneficiaries of this "artificial heart," which extended the window period for a heart transplant.

"We hope that the pediatric version of the 'artificial heart' can bring more hope for survival to children with heart failure." This is the shared expectation of all researchers.