Lung transplants have been touted as lifesavers for COVID-19 patients, but Dr. Howard J. Huang, pulmonologist and medical director of the lung transplant program at Houston Methodist J.C. Walter Jr. Transplant Center, cautions that the intervention is only appropriate in rare cases.

Dr. Huang says the criteria for coronavirus-related lung transplants is still evolving, but the patient's condition and age, time of disease progression and other factors make the treatment "an extreme salvage maneuver."

"At the individual level, each of these transplants is an absolute miracle," says Dr. Huang. "But at the population level, given the number of overall COVID-19 cases, these transplants make no dent in the problem. They benefit a few select candidates with irrecoverable lung failure."

What our experts have learned about lung transplants and COVID-19

In continuing education presentations, Dr. Huang notes that pulmonologists are still learning from each transplant. But most now agree, he says, that they should be done at least four to six weeks after the onset of disease in patients, younger than 65, who, though likely to die without new lungs, are awake enough to participate in the decision-making process — and otherwise healthy enough to engage in rehabilitation prior to and after the transplant.

Dr. Huang adds he does expect a new category of lung transplant patients to emerge from the pandemic: those who develop or exacerbate chronic lung disease as a result of infection. Thus far, almost all of the COVID-19 related transplants have involved patients with acute lung disease, not chronic.

Those transplants have made headlines around the country — heroic, last-ditch interventions that rescue people with seemingly fatal lung damage. At the start of the pandemic, transplants were not expected to be a treatment option.

Still, lung transplants for the coronavirus — there've been fewer than 100 in the U.S., according to estimates — treat just a tiny fraction of the more than 2 million hospitalizations there have now been for severe cases of the disease.

Houston Methodist has performed eight of those transplants, all double-lung procedures, one a heart-lung procedure. Additional patients, on life-support machines that circulate the blood through an oxygenating system, are on a list waiting for lungs to become available.

Is there a right time for COVID-19-related lung transplant?

Dr. Huang says the key to transplant is that the patient's COVID-19 lung damage is irreversible.

"There's got to be no other way out," says Dr. Huang. "It's transplant or begin end-of-life discussions."

But the proper timing can be an issue. In the first procedures, COVID-19 lung transplants were done earlier in the course of the disease, before it became clear that patients in dire shape sometimes did get better.

Also, some patients can continue to test positive for the virus for weeks after the infection was seemingly cleared. Others have received infected blood from donors. Dr. Huang emphasizes it can all take time to figure out.

What are the considerations for COVID-19-related lung transplants?

In addition to proper timing, some of the other considerations include:

• Transplant is not an optimal option when the patient has multiple organ failure, such as the liver or kidneys shutting down, or another active, uncontrolled infection, most commonly bacterial.
• Repeated blood transfusions can result in an abundance of antibodies that make it hard to find a compatible donor. Such transfusions are necessary because of blood loss caused by the patient's lingering illness and long-term extracorporeal membrane oxygenation (ECMO) — the machines that that temporarily replace the function of the lungs in some of the sickest transplant candidates.
• The severity of lung damage caused by COVID-19 causes scarring within the chest cavity that can make it difficult to remove the diseased organs, requiring more blood transfusion, longer surgery times and an increased risk of complications.
  
  

Though there have been a couple failures, news about coronavirus-related lung transplants has been overwhelmingly positive. But Dr. Huang notes that the real success rate won't be known for months to come still, when post-transplant outcomes are documented in statistics. Until then, doctors don't have much data yet.

"We're going to see more and more of these transplants in the next six months, nationally and worldwide," says Dr. Huang. "For now, they're best done at centers that do a high volume of high-risk surgeries. Not just any program can take on this level of risk."