Favorable survival outcomes among COVID-19 lung transplant recipients

By Nidhi Saha, BDSReviewed by Benedette Cuffari, M.Sc.Oct 16 2022

A recent The Annals of Thoracic Surgery journal study reports that the survival rate of lung transplant (LT) recipients who experienced respiratory failure following infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was not significantly different than the survival rates among patients who received an LT due to other lung etiologies.

Study: A Matched Survival Analysis of Lung Transplant Recipients with Covid-19–related Respiratory Failure. Image Credit: mi_viri / Shutterstock.com

Background

The coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 infection, has infected over 624 million and caused over 6.56 million deaths. COVID-19 primarily affects lung tissues; however, it can also cause damage to various other organs. 

COVID-19 precipitates two significant forms of respiratory failure: pulmonary fibrosis and acute respiratory distress syndrome (ARDS). Both conditions may require extracorporeal membrane oxygenation (ECMO), prolonged mechanical ventilation, supplemental oxygen, and physical deconditioning. 

LT is often recommended for patients with end-stage respiratory failure. More recently, some clinicians have also recommended LT for patients experiencing severe COVID-19 that is not responding to any other medical treatment.

As compared to respiratory failure due to other causes, patients with COVID-19-related respiratory failure often exhibit a poorer initial presentation prior to LT. Nevertheless, previous studies have reported that the survival rates of both types of LT recipients are similar.

Study findings

Between 2006 and 2021 in the United States, 37,333 individuals were listed for LT after lung injury due to other etiologies, whereas 334 patients were recommended LT due to respiratory failure following SARS-CoV-2 infection.

Within the COVID-19 cohort, patients were more likely to have higher lung allocation scores (LAS) that averaged 78.3 as compared to an average of 43.1 in the other group. Similarly, 51.2% of the COVID-19 group required ECMO as compared to 1.8% in the non-COVID-19 group, whereas 36.5% and 3.0% required ventilation, respectively.

Six months after their initial diagnosis, LT was performed in 87.9% and 63.3% of COVID-19 patients and those with other lung-related dysfunctions, respectively.

While on the waitlist for new lungs, COVID-19 patients were less likely to die. The likelihood of receiving LT was comparable among both patient groups. Nevertheless, COVID-19 LT recipients waited for a transplant for a median of 14 days as compared to 48 days for other LT recipients.

COVID-19 LT recipients were more likely to have a lower functional status, be admitted to the intensive care unit (ICU), be put on ECMO, and require ventilation. The LAS of these patients was significantly higher prior to LT. 

The overall duration of hospitalization for COVID-19 LT recipients was significantly higher than other LT recipients. Seventy-two hours following their procedures, COVID-19 patients were also more likely to be on an ECMO, remain intubated, and require dialysis. Despite the overall worse functional status in these patients, both COVID-19 and other LT recipients exhibited similar acute rejection, 30-day mortality, and 90-day mortality rates.

It should be noted that post-transplantation, COVID-19 LT recipients had worse functional outcomes. The researchers hypothesize that this may be due to the acutely ill state of these patients prior to their transplant.

Conclusions

COVID-19 patients who experience respiratory failure often deteriorate rapidly, which has led many clinicians to investigate the potential benefits LT may offer these patients. In the current study, the researchers similarly found that COVID-19 patients with respiratory failure were severely ill when first placed on the waitlist for LT.

In fact, many of these patients were on ECMO, mechanical ventilation, or in the ICU when first listed to receive an LT. The worse LAS among COVID-19 respiratory failure patients significantly reduced their waitlist time, thus also reducing their likelihood of death while waiting for lungs.

Despite the worse acute state of these patients, both COVID-19 LT recipients and LT recipients with other etiologies exhibited similar six-month survival rates. Thus, the favorable survival outcomes in COVID-19 LT recipients can support altering current consensus guidelines for LT in this patient population.

Some of the different factors that may contribute to the high survival rates in COVID-19 LT recipients may include their careful selection prior to being placed on the waitlist, overall younger age, the nature of COVID-19, as well as recent improvements in how critical COVID-19 patients are cared for in the ICU.

Overall, a history of COVID-19-related lung failure did not increase the risk of mortality in LT recipients. Nevertheless, due to the high rate of complications in these patients after their procedure, further studies are needed to determine the rate at which COVID-19 LT recipients can return to baseline levels following their transplant.