Lung transplantation for the treatment of irreversible acute respiratory distress syndrome

Lung Transplantation in the United States for COVID-19 Related Lung Disease During the Pandemic

PURPOSE

Lung transplantation (LTx) is a potential intervention for end-stage COVID-19 lung disease. Current literature is sparse regarding the outcomes of LTx for COVID-19 related acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF). This study aims to characterize outcomes and patterns of LTx for COVID-19 related lung disease throughout the pandemic.

METHODS

Patients who underwent LTx during the pandemic for COVID-19 related lung disease were retrospectively identified using the UNOS registry. Demographics, as well as outcomes measures and nationwide patterns of care were collected and analyzed.

RESULTS

A total of 510 adult cases of LTx for COVID-19 (259 ARDS, 251 PF) were compared to 4,031 without COVID-19 (3,994 PF, 37 ARDS). Patients who received LTx for COVID-19 ARDS did not differ in 2-year survival when compared to those with COVID-19 PF (81.9% vs 77.2%, p = 0.4428). Compared to non-COVID-19 etiologies, COVID-19 ARDS patients had higher rates of stroke (2.3% vs 0%, p = 0.0005), lower rates of graft failure (12.8% vs 36.1%, p = 0.0003) and post-transplant ECMO (29.6% vs 41.7%, p = 0.0002), and improved 2-year survival following LTx (81.9% vs 61.7%, p = 0.0064). No difference in 2-year survival following LTx was observed between patients with COVID-19 and non-COVID-19 PF (77.2% vs 71.8%, p = 0.34). Rates of LTx spiked with variant emergence and declined with rounds of vaccination.

CONCLUSION

Our results are consistent with early reports of survival outcomes following LTx for COVID-19 ARDS and PF while providing an increased layer of granularity. LTx may be considered as a safe and effective intervention for COVID-19 lung disease.

Pushing the Survival Bar Higher: Two Decades of Innovation in Lung Transplantation

Survival after lung transplantation has significantly improved during the last two decades. The refinement of the already existing extracorporeal life support (ECLS) systems, such as extracorporeal membrane oxygenation (ECMO), and the introduction of new techniques for donor lung optimization, such as ex vivo lung perfusion (EVLP), have allowed the extension of transplant indication to patients with end-stage lung failure after acute respiratory distress syndrome (ARDS) and the expansion of the donor organ pool, due to the better evaluation and optimization of extended-criteria donor (ECD) lungs and of donors after circulatory death (DCD). The close monitoring of anti-HLA donor-specific antibodies (DSAs) has allowed the early recognition of pulmonary antibody-mediated rejection (AMR), which requires a completely different treatment and has a worse prognosis than acute cellular rejection (ACR). As such, the standardization of patient selection and post-transplant management has significantly contributed to this positive trend, especially at high-volume centers. This review focuses on lung transplantation after ARDS, on the role of EVLP in lung donor expansion, on ECMO as a principal cardiopulmonary support system in lung transplantation, and on the diagnosis and therapy of pulmonary AMR.

Lung transplant outcomes after acute respiratory distress syndrome requiring extracorporeal life support: Lessons from the COVID-19 pandemic

OBJECTIVE

Lung transplant for acute respiratory distress syndrome in patients supported with extracorporeal membrane oxygenation was rare before 2020, but was rapidly adopted to rescue patients with COVID-19 with lung failure. This study aims to compare the outcomes of patients who underwent lung transplant for COVID-associated acute respiratory distress syndrome and non-COVID acute respiratory distress syndrome, and to assess the impact of type and duration of extracorporeal membrane oxygenation support on survival.

METHODS

Using the United Network for Organ Sharing database, we identified 311 patients with acute respiratory distress syndrome who underwent lung transplant from 2007 to 2022 and performed a retrospective analysis of the patients who required extracorporeal membrane oxygenation preoperatively, stratified by COVID-associated acute respiratory distress syndrome and non-COVID acute respiratory distress syndrome listing diagnoses. The primary outcome was 1-year survival. Secondary outcomes included the effect of type and duration of extracorporeal membrane oxygenation on survival.

RESULTS

During the study period, 236 patients with acute respiratory distress syndrome and preoperative extracorporeal membrane oxygenation underwent lung transplant; 181 patients had a listing diagnosis of COVID-associated acute respiratory distress syndrome (77%), and 55 patients had a listing diagnosis of non-COVID acute respiratory distress syndrome (23%). Patients with COVID-associated acute respiratory distress syndrome were older, were more likely to be female, had higher body mass index, and spent longer on the waitlist (all P < .02) than patients with non-COVID acute respiratory distress syndrome. The 2 groups had similar 1-year survival (85.8% vs 81.1%, P = .2) with no differences in postoperative complications. Patients with COVID-associated acute respiratory distress syndrome required longer times on extracorporeal membrane oxygenation pretransplant (P = .02), but duration of extracorporeal membrane oxygenation support was not a predictor of 1-year survival (P = .2).

CONCLUSIONS

Despite prolonged periods of pretransplant extracorporeal membrane oxygenation support, selected patients with acute respiratory distress syndrome can undergo lung transplant safely with acceptable short-term outcomes. Appropriate selection criteria and long-term implications require further analysis.

Impact of bridging veno-venous extracorporeal membrane oxygenation to COVID-19 lung transplantation

Background

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) therapy is being increasingly used as respiratory support for patients with severe coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome (ARDS). However, the long-term outcome of VV-ECMO as a bridge to lung transplantation in COVID-19-associated ARDS remains unclear, hence the purpose of this study aimed to evaluate its long-term outcome, safety, and feasibility.

Methods

This was a retrospective cohort study from an institutional lung transplantation database between June 2020 and June 2022. Data on demographics, pre-transplantation laboratory values, postoperative outcomes, preoperative and postoperative transthoracic echocardiography findings, and survival rates were collected. Chi-square, Mann-Whitney U, Student's t, Kaplan-Meier, and Wilcoxon signed-rank tests were used for analysis.

Results

Twenty-five patients with COVID-19-associated ARDS underwent lung transplant surgery with VV-ECMO bridge. Unfortunately, six patients with COVID-19-associated ARDS using VV-ECMO died while waiting for transplantation during the same study period. Patients with VV-ECMO bridge were a more severe cohort than 16 patients without VV-ECMO bridge (lung allocation score: 88.1 vs. 74.9, P<0.001). These patients had longer intensive care unit and hospital stays (P=0.03 and P=0.02, respectively) and a higher incidence of complications after lung transplantation. The one-year survival rate of patients with VV-ECMO bridge was lower than that of patients without (78.3% vs. 100.0%, P=0.06), but comparable to that of patients with other lung transplant indications (84.2%, P=0.95). Echocardiography showed a decrease in the right ventricular systolic pressure (P=0.01), confirming that lung transplantation improved right heart function.

Conclusions

Our findings suggest that VV-ECMO can be used to safely bridge patients with COVID-19 associated ARDS with right heart failure.

Severe Lung Dysfunction and Pulmonary Blood Flow during Extracorporeal Membrane Oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is indicated for patients with severe respiratory and/or circulatory failure. The standard technique to visualize the extent of pulmonary damage during ECMO is computed tomography (CT).

PURPOSE

This single-center, retrospective study investigated whether pulmonary blood flow (PBF) measured with echocardiography can assist in assessing the extent of pulmonary damage and whether echocardiography and CT findings are associated with patient outcomes.

METHODS

All patients (>15 years) commenced on ECMO between 2011 and 2017 with septic shock of pulmonary origin and a treatment time >28 days were screened. Of 277 eligible patients, 9 were identified where both CT and echocardiography had been consecutively performed.

RESULTS

CT failed to indicate any differences in viable lung parenchyma within or between survivors and non-survivors at any time during ECMO treatment. Upon initiation of ECMO, the survivors (n = 5) and non-survivors (n = 4) had similar PBF. During a full course of ECMO support, survivors showed no change in PBF (3.8 ± 2.1 at ECMO start vs. 7.9 ± 4.3 L/min, p = 0.12), whereas non-survivors significantly deteriorated in PBF from 3.5 ± 1.0 to 1.0 ± 1.1 L/min (p = 0.029). Tidal volumes were significantly lower over time among the non-survivors, p = 0.047.

CONCLUSIONS

In prolonged ECMO for pulmonary septic shock, CT was not found to be effective for the evaluation of pulmonary viability or recovery. This hypothesis-generating investigation supports echocardiography as a tool to predict pulmonary recovery via the assessment of PBF at the early to later stages of ECMO support.

Lung Transplantation in Patients With COVID-19-The Early National Experience

Lung transplant (LT) has become a viable option for COVID-19 patients suffering from end-stage Acute Respiratory Distress Syndrome (ARDS). This analysis sought to describe the early national experience of COVID-19 patients who received LT and compare transplant characteristics and short-term outcomes of COVID-19 and non-COVID-19 ARDS LT recipients. We queried the Organ Procurement and Transplantation database for adults (≥18 years old) receiving LT from January 2009 to March 31, 2022 with diagnoses of COVID-19 or ARDS. We identified 353 COVID-19 and 64 non-COVID-19 ARDS LT recipients. COVID-19 recipients were older (median age: 51, interquartile range [40-57] years vs 41 [26-52]; P < 0.001), more predominantly male (78% (n = 274) vs 55% (n = 35), P < 0.001), and had higher body mass indices (median 27.2 interquartile range [24.5-30.9] vs 25.4 [22.1-28.6]; P < 0.01) than non-COVID-19 ARDS recipients. COVID-19 LT recipients were less frequently reliant on extra-corporeal membrane oxygenation at 72 hours after transplant (26% (n = 80) vs 31% (n = 15), P < 0.001), and were less frequently dependent on dialysis post-transplant than non-COVID-19 ARDS LT recipients (14% (n = 43) vs 23% (n = 14); P = 0.01). Survival at 90 days post-transplant was comparable for the non-COVID ARDS (90%, n = 54) and COVID-19 (94%, n = 202) LT recipients with available follow-up (P = 0.17). LT appears to be a viable therapy for COVID-19 patients with end-stage lung disease. COVID-19 LT and non-COVID-19 ARDS LT recipients have comparable 90 days post-transplant survival.

Lung Transplantation for Acute Respiratory Distress Syndrome

In this review, we discuss the outcomes of patients with severe acute respiratory distress syndrome (ARDS). We discuss evidence that suggests that a significant proportion of patients with ARDS develop end-stage lung disease and die of pulmonary complications. In carefully selected patients with permanent lung damage, lung transplant can be a life-saving treatment.

Clinical relevance of lung transplantation for COVID-19 ARDS: a nationwide study

BACKGROUND

Although the number of lung transplantations (LTx) performed worldwide for COVID-19 induced acute respiratory distress syndrome (ARDS) is still low, there is general agreement that this treatment can save a subgroup of most severly ill patients with irreversible lung damage. However, the true proportion of patients eligible for LTx, the overall outcome and the impact of LTx to the pandemic are unknown.

METHODS

A retrospective analysis was performed using a nationwide registry of hospitalised patients with confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-Cov-2) infection admitted between January 1, 2020 and May 30, 2021 in Austria. Patients referred to one of the two Austrian LTx centers were analyzed and grouped into patients accepted and rejected for LTx. Detailed outcome analysis was performed for all patients who received a LTx for post-COVID-19 ARDS and compared to patients who underwent LTx for other indications.

RESULTS

Between January 1, 2020 and May 30, 2021, 39.485 patients were hospitalised for COVID-19 in Austria. 2323 required mechanical ventilation, 183 received extra-corporeal membrane oxygenation (ECMO) support. 106 patients with severe COVID-19 ARDS were referred for LTx. Of these, 19 (18%) underwent LTx. 30-day mortality after LTx was 0% for COVID-19 ARDS transplant recipients. With a median follow-up of 134 (47-450) days, 14/19 patients are alive.

CONCLUSIONS

Early referral of ECMO patients to a LTx center is pivotal in order to select patients eligible for LTx. Transplantation offers excellent midterm outcomes and should be incorporated in the treatment algorithm of post-COVID-19 ARDS.

Lung transplantation for severe COVID-19-related ARDS

Background:

Lung transplantation (LT) is the gold standard for various end-stage chronic lung diseases and could be a salvage therapeutic option in acute respiratory distress syndrome (ARDS). However, LT is uncertain in patients with coronavirus disease 2019 (COVID-19)-related ARDS who failed to recover despite optimal management including extracorporeal membrane oxygenation (ECMO). This study aims to describe the pooled experience of LT for patients with severe COVID-19-related ARDS in Korea.

Methods:

A nationwide multicenter retrospective observational study was performed with consecutive LT for severe COVID-19-related ARDS in South Korea (June 2020–June 2021). Data were collected and compared with other LTs after bridging with ECMO from the Korean Organ Transplantation Registry.

Results:

Eleven patients with COVID-19-related ARDS underwent LT. The median age was 60.0 years [interquartile range (IQR), 57.5–62.5; six males]. All patients were supported with venovenous ECMO at LT listing and received rehabilitation before LT. Patients were transplanted at a median of 49 (IQR, 32–66) days after ECMO cannulation. Primary graft dysfunction within 72 h of LT developed in two (18.2%). One patient expired 4 days after LT due to sepsis and one patient underwent retransplantation for graft failure. After a median follow-up of 322 (IQR, 299–397) days, 10 patients are alive and recovering well. Compared with other LTs after bridging with ECMO (n = 27), post-transplant outcomes were similar between the two groups.

Conclusions:

LT in patients with unresolving COVID-19-related ARDS were effective with reasonable short-term outcome.

Lung transplantation for acute respiratory distress syndrome - a retrospective European Cohort Study

BACKGROUND

The published experience of lung transplantation (LTX) in acute respiratory distress syndrome (ARDS) is limited. The aim of this study was to investigate the contemporary results of LTX attempts in ARDS in major European centers.

METHODS

We conducted a retrospective multicenter cohort study of all patients listed for LTX between 2011 and 2019. We surveyed 68 centers in 22 European countries. All patients admitted to the waitlist for lung transplantation with a diagnosis of "ARDS//pneumonia" were included. Patients without extracorporeal membrane oxygenation (ECMO) or mechanical ventilation were excluded. Patients were followed until October 1st 2020 or death. Multivariable analysis for 1-year survival after listing and lung transplantation were performed.

RESULTS

Forty-eight centers (74%) with a total transplant activity of 12 438 lung transplants during the 9-year period gave feedback. Forty patients with a median age of 35 years were identified. Patients were listed for LTX in 18 different centers in 10 countries. Thirty-one-patients underwent LTX (0·25% of all indications) and 9 patients died on the waitlist. Ninety percent of transplanted patients were on ECMO in combination with mechanical ventilation before LTX. On multivariable analysis, transplantation during 2015 until 2019 was independently associated with better 1-year survival after LTX (odds ratio 10.493, 95% CI 1.977, 55.705, p=0.006). Sixteen survivors out of 23 patients with known status (70%) returned to work after LTX.

CONCLUSION

LTX in highly selected ARDS patients is feasible and outcome has improved in the modern era. The selection process remains ethically and technically challenging.