Receiving an organ transplant is a notoriously difficult process. By one estimate, there are 122,000 patients waiting for donated organs across the United States, and each day, 22 people die due to shortages of available organs from donors. So it’s no surprise that in 2014, when Stan Larkin’s heart failed, he couldn’t immediately get a transplant.

Larkin, now 25, was discharged from his hospital at the University of Michigan, though. And for 555 days, he lived without a real heart. Instead, an artificial heart implanted inside him—powered by a driver he wore in a backpack—kept him alive.

Larkin has a genetic disease called familial cardiomyopathy, which prevents his heart from being able to pump blood as efficiently as someone without the disease. He was the first person in the state of Michigan to be discharged from the hospital temporarily implanted with a total artificial heart.

But he wasn't the only one in his family. His brother Dominique, who also has the disease, relied on the same model of artificial heart—SynCardia’s portable Freedom driver—for several weeks before receiving his own transplant. Stan, however, wasn't matched with a donor quite as quickly. Rather than living in the hospital for months, he carried the 13.5-pound driver that powers the heart inside a backpack until he came back to receive a transplant in May. 

The portable artificial heart device worn by Larkin. Image credit: SynCardia

Oh, and he played basketball with it. The driver had to be exchanged “about 10 times,” one surgeon remarked at a press conference, “because this thing wasn’t built for pick-up basketball.”

“It brought my life back,” Larkin said of the device.

Artificial hearts have been around for decades as temporary methods of keeping a patient alive while waiting for a heart donor, but it’s still relatively rare for patients to leave the hospital completely reliant a mechanical heart. Drivers that keep artificial hearts pumping can weigh more than 400 pounds. The SynCardia device Larkin used was piloted in clinical trials starting in 2010 and approved by the FDA in 2014.

While Larkin may be the first person to test it out on the basketball court, he's not the only user who was determined to stay active with or without a heart. In 2014, a patient used the Freedom driver to walk the course of the 4.2-mile Pat’s Run in Tempe, Arizona.

[h/t ScienceAlert]