When Mariam’s transplanted heart began to fail, her doctors made a bold decision

In June 2021, 11-year-old Mariam Tannous collapsed in the bathroom at home. She was unresponsive and not breathing. Her dad called 911 and her older brother started CPR.

Mariam had already skirted death four years earlier when she’d undergone a heart transplant at The Hospital for Sick Children (SickKids). When she arrived at the SickKids critical care unit that day after collapsing, it was clear that her donated heart was failing.

Mariam was born with two forms of congenital heart disease. The right side of her heart was severely malformed and one of its main valves was leaky. She was born in Syria and when she was three, she’d travelled to Lebanon to have surgery to repair the leaking valve. When her family moved to Canada in 2015, she was referred to SickKids’ renowned Labatt Family Heart Centre. There, her medical team determined her surgery had been largely ineffective. She was deteriorating and put on the transplant list.

Mariam received her new heart in 2017 at the age of seven. For four years, she lived a typically active life for someone her age — she swam and played soccer. Her family was optimistic the worst was behind them.

When Mariam’s donated heart began to fail, a second transplant was her only hope. But the process to receive a new donated heart can take many months, which she didn’t have. She was in the cardiac intensive care unit, gravely ill. Some children with severe heart failure can be put on a ventricular assist device (VAD), a mechanical pump implanted in the heart to help it move blood through the body. Roughly five SickKids patients will require one each year. But for Mariam, a VAD wasn’t suitable for the extent of her heart failure. Unless another donor heart became available within days, possibly weeks, she wouldn’t likely survive.  

It was a desperate situation that called for extraordinary measures. Mariam’s cardiologist Dr. Aamir Jeewa, and surgeon Dr. Osami Honjo, came up with a bold, last-ditch plan — one that is rarely done in children, and had never been done in Canada.  

They suggested implanting a total artificial heart (TAH). Unlike a VAD, which assists a damaged heart, a TAH replaces the damaged heart, its main pumping chambers cut away and substituted for large mechanical pumps. But these devices are designed for adults, not children.

“Total artificial hearts are rarely used in paediatric patients due to their size,” said Dr. Jeewa, medical director of the ventricular assist device program. “The device, intended for larger adults, has a large set of mechanical pumps surgically connected to vessels inside the chest and are driven by connections outside of the body to a large controller unit and runs 24 hours a day.” 

It was a heroic plan that came with no guarantees and plenty of risk. Mariam’s parents, Issa and Linda, were faced with a difficult choice. “It was a hard decision,” said Linda. “But SickKids saved her life in the beginning, so we believed they would save her life again.” 

With the family’s go-ahead, Dr. Jeewa and Dr. Honjo, surgical director of heart transplantation and mechanical circulatory support, quickly began consulting with colleagues in the U.S. about the nuances of TAH surgery and post-operative care.

“Although we often manage other types of assistive devices, everything about the total artificial heart was new for us,” said Dr. Honjo. “The fact that Mariam was one of the smallest patients in the world to have this device also presented a significant technical challenge.”

The surgery lasted 14 hours. There was old scarring to navigate, a lot of bleeding, and it was hard to fit the device inside Mariam’s small frame. Her large surgical cavity was covered with a patch for five days to allow time for her body to adjust, which it did. Her blood pressure eventually stabilized, and Mariam started the long recovery period, learning to walk, eat and sleep while attached to a machine nearly as tall as she was.

But it worked. The artificial heart kept Mariam alive for two months, when another donor heart became available. She had her second transplant surgery in September 2021. Ten days later, she was well enough to go home.

Today, Mariam has resumed her life of sports, school and doting on the family dog, appropriately named Lucky. She’s never far from the watchful care and monitoring of her cardiology team at SickKids, one of the few places in Canada where she could have been given yet another chance. Said Dr. Honjo: “Mariam and her family have gone through a lot, and it’s been my honour to join them on this journey. I’m so happy to see her thrive and go back to her life once again.”

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Torstar, the Star’s parent company, is in a fundraising and educational partnership with The Hospital for Sick Children to help raise $1.5 billion for new facilities. This content was produced by SickKids as part of that partnership.

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DisclaimerThis content was produced as part of a partnership and therefore it may not meet the standards of impartial or independent journalism.