Hope of boosting supply of donor hearts suitable for transplantation in unique multicenter study
IMPROVED HEART is the first prospective multicenter study in the world where evaluation of organ donors’ cardiac function is going to take place. The aim of the study is to include hearts with mild dysfunction to be acceptable for transplantation as well. In Sweden, hearts like this have been transplanted for several years with good results, but the status of this research has not been sufficient to change international practice.
Every fourth heart examined for possible donation risks being ruled out because of disturbed cardiac function. In the absolute majority of cases, this is a transient stress reaction observed in association with progression of brain death, also known as stress cardiomyopathy or Takotsubo syndrome. According to the researchers this condition, being a temporary dysfunction, has no bearing on the outcome of transplantation (1). In Sweden, surgeons have been transplanting these hearts for several years with good results.
“There are several retrospective studies, ours and others’, showing it’s safe to use these hearts for transplantation (1). However, the status of this research isn’t robust enough to change current practice internationally, and there’s an ongoing debate in the transplant community about whether this is something we should do. Surprisingly, there are no prospective studies investigating this.”
The speaker is Jonatan Oras, senior consultant at the Department of Anesthesiology and Intensive Care Medicine at Sahlgrenska University Hospital, and Associate Professor (docent) and researcher at Sahlgrenska Academy’s Institute of Clinical Sciences.
Oras has now received a grant of SEK 1.2 million from the Swedish Heart-Lung Foundation for IMPROVED HEART (2), the first prospective multicenter study worldwide with this research focus. Organ donors’ cardiac function is being systematically evaluated, and hearts exhibiting mild dysfunction can be accepted for transplant. To assess whether this has any significance, the study follows outcomes among the heart recipients.
In Sweden, only Sahlgrenska University Hospital in Gothenburg and Skåne University Hospital (SUS) in Lund perform heart transplants. The study, based in Gothenburg, is being conducted jointly by Oras and Göran Dellgren, cardiothoracic surgeon and adjunct professor at the Institute of Medicine. They also plan to recruit another two to three centers in Scandinavia.
Massive organ shortage makes every additional heart crucially important
Organ scarcity is considered the key reason why no more patients are being heart transplanted. Since cardiac dysfunction is so common among organ donors, the number of available donor hearts will rise markedly if this group’s hearts can be used as well, Oras thinks. In other words, each extra heart utilized enables another heart transplant.
“We’ve also seen that it’s primarily young donors who are affected by cardiac dysfunction, and hearts from young donors are especially valuable because they’re associated with better results for the recipients. So, the heart evaluation we’re doing in the study will allow further transplantations, even if we’re already using some of these hearts today.”
Oras and Dellgren estimate that IMPROVED HEART may boost the number of heart donors, and accordingly the number of heart transplants too, by 20–40 percent.
Figure 2 Temporal changes in the ejection fractions. Changes in ejection fraction over time from pretransplant (far left) to one-year follow-up (far right). The blue line represents recipients of hearts with normal function, the red line represents recipients of hearts with left ventricular dysfunction. There were no differences in ejection fraction at any time post-transplantation. (Recovery of heart function)
What makes the project challenging is its nightmarish logistics. Organ donors are admitted at an uneven rate to all the roughly 80 intensive care units (ICUs) nationwide.
“Getting a systematic donation heart evaluation when the situation suddenly arises, in all these places, and where many units receive donors relatively seldom, is a major challenge. This must then be coordinated with monitoring the heart recipient. Fortunately, we have donation units with highly proficient transplantation coordinators who help us with the heart examination.”
In Sweden, there is also a well-developed organ donation network. There are dedicated doctors and nurses responsible for organ donation at each hospital that can assist with practical details at their respective ICUs. The donation units and this network are essential for doing this type of research. Perhaps this is why no one, anywhere else in the world, has conducted any similar study before.
Pictures: Genre image (photo: iStock) and portrait image of Jonatan Oras (photo: Jonathan Moonen)
Text: Susanne Lj Westergren
1. Read more in the 2019 study “Left ventricular dysfunction in potential heart donors and its influence on recipient outcomes” and press release “New findings enable more heart donations”.
2. IMPROVED HEART: The importance of the donor’s cardiac function for the recipient’s outcome – a prospective study to boost the use of donor hearts: SEK 1.2 million.
3. A total of SEK 29 million from the Swedish Heart-Lung Foundation in the autumn round of awards. (in Swedish)
4. More about the Swedish Heart-Lung Foundation’s heart disease and cardiac arrest research. (in Swedish)