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For patients with advanced heart failure, a heart transplant can be the solution. However, the shortage of donor hearts remains a challenge and complications can arise after transplantation. During her PhD, Selma Kaffka genaamd Dengler studied donor heart preservation with machine perfusion to increase available donor hearts and chances of a successful transplant. She defended her thesis on February 18.  

Making every donor heart count 

For patients with advanced heart failure, there are two options: mechanical support or a heart transplant. ‘Due to the shortage of donor hearts, strict criteria determine who qualifies for the transplant. This is why we need to make every donor heart count. My research focused on how improve donor heart preservation,’ Selma explains.  

Expanding the donor pool 

Increasing the number of donor hearts is one approach to help as many people with end-stage heart failure as possible. Historically, donor hearts were primarily obtained from brain-dead patients. However, researchers have now also explored ways to preserve hearts after circulatory death, which could aid in expanding the donor pool and help more people with end-stage heart failure.  

Machine perfusion as a better way to preserve donor hearts 

‘Previously, donor hearts from brain death donors were stored on ice, but after just four hours, the chances of primary graft dysfunction increase rapidly,’ Selma explains. ‘This limiting factor shows the need for alternative methods.’ At the same time, donor hearts from circulatory death donors already endure warm ischemia: they are deprived of oxygen but remain at high temperatures, causing additional damage. This makes them unsuitable for preservation on ice.  

Machine perfusion changed the scenario. With this method, a machine supplies the donor heart with oxygen and blood during preservation. In 2015, machine perfusion became a clinical application for the first time in donor hearts from brain dead donors. ‘The introduction of machine perfusion in donor hearts from circulatory death donors increased the available donor hearts substantially. We started applying machine perfusion in the Netherlands in 2021 and saw an increase in the number of heart transplantation from 40 to 79 last year.’ 

Preventing the need for heart transplants 

Improved preservation of the heart could not only greatly improve transplant success, but it could also offer opportunities for regenerative strategies. Selma is part of the RegMed XB cardiovascular moonshot, the goal of which is to repair the heart outside the human body and place it back, potentially reducing the need for heart transplants all together. ‘To achieve this, the heart needs to be stored in stable conditions outside the body for a long time. More research into preservation techniques without functional decline is therefore crucial,’ she emphasizes.  

The next step for Selma 

Looking back, Selma recalls the challenges she faced at the start of her PhD: ‘I was the first researcher in my consortium, making it a completely different experience from getting onto a “moving train”. But that also allowed me to gain insights into political and strategic aspects of medical research. I have been able to learn and grow in many ways, increasing my understanding of other perspectives as well.’  

Selma currently focusses on becoming a heart surgeon, which limits her research time. However, she remains involved in the field, the future of which has a lot of potential, Selma believes: ‘Advancements in heart preservation and regenerative medicine hold great promise for heart failure patients’.