To better serve patients in need of lung transplant, researchers have recently published two studies that focus on outcomes for patients on waitlists, and one that focuses on patients who received transplants due to COVID-19. Errol Bush, surgical director of the advanced lung disease and lung transplant program, and his team have presented new findings in hepatitis C-positive and COVID lung transplant outcomes, as well as racial disparities in the former lung allocation system.
“We’ve shown that those who receive organs from hep C donors can be treated, and that the outcomes are the same.” —Errol Bush
Hepatitis C-Positive Lung Transplants
In a study on lungs from donors with hepatitis C (HCV D+) published in The Journal of Thoracic and Cardiovascular Surgery, Bush and his team showed that 20% of the patients who declined these organs did not end up getting transplants. Five percent died while still on the waitlist and another 15% were removed from the waitlist because they got too sick (and later died). Sixty percent did eventually get transplanted over the course of a three-year period. The study is the first of its kind for thoracic transplant; Bush is senior author and surgery resident and Ph.D. candidate Jessica Ruck is primary author.
This research builds on the team’s previous study showing that three years post-transplant, patients who receive HCV D+ lungs who are HCV-seronegative have similar outcomes compared with patients who received HCV D- (hepatitis C-negative donor) lungs.
HCV-positive lungs fall into two categories — viremic and seropositive. Those who receive viremic lungs get hepatitis C 99% of the time, while those who receive seropositive lungs get hepatitis C less frequently. For patients who get hepatitis C from their transplant, though, it is an easily treatable disease, Bush says.
“We’ve shown that those who receive organs from hep C donors can be treated, and that the outcomes are the same,” he says. “But if patients turn down the HCV+ lungs, there’s a 20% chance of death.”
The study used data from patients who declined an organ offer from a donor with HCV, not those who declined even hearing about HCV+ donor organ offers. In addition, Bush’s team found that there is 17% reduction in waitlist mortality simply from patients signing up to consider HCV+ donor organs, as they get notified about more organ offers. In June, Ruck was awarded the Paul C. Samson Resident Prize at the Western Thoracic Surgical Association annual meeting, a top honor, for her HCV work.
Lung Transplant Outcomes in COVID-19
In another first-of-its-kind study, published in The Journal of Thoracic and Cardiovascular Surgery and also authored by Bush and Ruck, the team found that one-year post-transplant outcomes for recipients with end-stage lung disease from severe COVID-19 were similar to those of recipients transplanted for other lung transplant indications. The paper shows that COVID-19 was associated with higher risk of immediate postoperative complication, but a similar risk of acute rejection and one-year mortality despite more severe pre-transplant illness.
What’s remarkable, Bush says, is that many of these patients transplanted for COVID were hospitalized and on a ventilator or ECMO prior to their transplant — all factors that are usually associated with bad outcomes after transplant. The median lung allocation score — higher scores represent a more acute need for transplant — for those without COVID was 40, for those with COVID, it was 80.
“So, in theory, they’re twice as sick or twice as likely to die on the waitlist as anyone else,” Bush says.
Bush says these patients likely had better outcomes because COVID is an acute illness, and these patients probably had isolated lung disease, compared with other patients who may have been chronically ill for years. “If you fix the lungs, they can bounce back from this,” he says.
The study is a follow-up to a 90-day outcomes study from Bush’s team that found that recipients who had acute respiratory distress syndrome (ARDS) due to COVID-19 had similar outcomes to those who had non-COVID ARDS.
Racial Disparities in Lung Transplant Allocation
Another recent study published in The Annals of Thoracic Surgery looked at racial disparities in the Lung Allocation Score (LAS), and determined that African American and Hispanic candidates were less likely to receive lung transplants than white candidates. In particular, Hispanic candidates over age 65 and non-white candidates from impoverished communities were less likely to receive lung transplants.
During the study period, 83% of white patients and 77% of African American and Hispanic patients received lung transplants. After accounting for clinical and demographic covariates as well as year of transplant, African American candidates were 16% less likely to receive lung transplants than white candidates, and Hispanic candidates were 18% less likely to receive transplants compared with white candidates.
Bush says there is systemic bias built into the LAS — for example, a patient belonging to a minority group and a white person may have the same lung function, but that level of lung function might be classified as “normal” for the minority patient and “abnormal” for the white patient. This could result in the white patient getting a transplant sooner. There are also nuances about living in an impoverished community that the LAS doesn’t account for, making those populations further disadvantaged in the LAS, he says.
In March, the allocation system changed from the LAS to what’s called the continuous allocation system, which Bush says is supposed to take more factors, including access, into consideration for lung transplant. For example, more points are given to patients who have blood types and body sizes that make it more challenging to find the right organ. Minority recipients who may have more antibodies to donor organs from non-minority donors due to genetic variation are also given more points under the new system.
“We don’t know if the same disparities will exist, but it was important to do this in the lung allocation system,” he says. “We need to highlight these disparities, and then we can try to address them. If we don’t know that they exist, then we’re unable to address them.”
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