Extracorporeal membrane oxygenation as a bridge to lung transplantation in the United States: an evolving strategy in the management of rapidly advancing pulmonary disease

Evaluation of the Current Urgency-Based Lung Allocation System in Korea with Simulation of the Eurotransplant Lung Allocation Score

PURPOSE

Due to the shortage of lung donors relative to the number of patients waiting for lung transplantation (LTx), more than one-third of patients on the waitlist have died without receiving LTx in Korea. Therefore, the importance of fair and effective allocation policies has been emphasized. This study investigated the characteristics of the current urgency-based allocation system in Korea by simulating the Eurotransplant lung allocation score (ET-LAS) using a nationwide multi-institutional registry for LTx in Korea.

MATERIALS AND METHODS

This study used data from the Korean Organ Transplantation Registry (KOTRY), along with additional retrospective data for ET-LAS calculation. A total of 194 patients were included in this study between January 2015 and December 2019. The Korean urgency definition classifies an LTx candidate as having statuses 0-3 according to urgency. The ET-LAS was analyzed according to the Korean urgency status.

RESULTS

In total, 92 patients received lung transplants at status 0, 85 at status 1, and 17 at status 2/3. The ET-LAS showed a bimodal distribution with distinct peaks corresponding to status 0 and non-status 0. There was no significant difference in the ET-LAS among non-status 0 patients. In logistic and decision tree analyses, oxygen supplementation methods, particularly oxygen masks and high-flow nasal cannulas, were significantly associated with a high ET-LAS (≥50) among non-status 0 patients.

CONCLUSION

Simulation of the ET-LAS with KOTRY data showed that the Korean urgency definition may not allocate lungs by urgency, especially for patients in non-status 0; therefore, it needs to be revised.

Outcomes of Recipients Aged 65 Years and Older Bridged to Lung Transplant With Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplant (BTT) has been used for critically ill candidates with excellent outcomes, but data on this strategy in older recipients remain limited. We compared outcomes of no BTT, mechanical ventilation (MV)-only BTT, and ECMO BTT in recipients of greater than or equal to 65 years. Lung-only recipients of greater than or equal to 65 years in the United Network for Organ Sharing database between 2008 and 2022 were included and stratified by bridging strategy. Of the 9,936 transplants included, 226 (2.3%) were MV-only BTT and 159 (1.6%) were ECMO BTT. Extracorporeal membrane oxygenation BTT recipients were more likely to have restrictive disease pathology, had higher median lung allocation score, and spent fewer days on the waitlist (all p < 0.001). Compared to no-BTT recipients, ECMO BTT recipients were more likely to be intubated or on ECMO at 72 hours posttransplant and had longer hospital lengths of stay (all p < 0.001). Extracorporeal membrane oxygenation BTT recipients had increased risk of 3 years mortality compared to both no-BTT (adjusted hazard ratio [aHR] = 1.48 [95% confidence interval {CI}: 1.14-1.91], p = 0.003) and MV-only recipients (aHR = 1.50 [95% CI: 1.08-2.07], p = 0.02). Overall, we found that ECMO BTT in older recipients is associated with inferior posttransplant outcomes compared to MV-only or no BTT, but over half of recipients remained alive at 3 years posttransplant.

Extracorporeal membrane oxygenation as a bridge to lung transplantation: Practice patterns and patient outcomes

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly relied on to bridge patients with respiratory failure to lung transplantation despite limited evidence for its use in this setting. This study evaluated longitudinal trends in practice patterns, patient characteristics, and outcomes in patients bridged with ECMO to lung transplant.

METHODS

A retrospective review of all adult isolated lung transplant patients in the United Network for Organ Sharing database between 2000 and 2019 was performed. Patients were classified as "ECMO" if supported with ECMO at the time of listing or transplantation and "non-ECMO" otherwise. Linear regression was used to evaluate trends in patient demographics during the study period. Trends in mortality were evaluated using Cox proportional hazards modeling, with time period as the primary covariate (2000-2004, 2005-2009, 2010-2014, or 2015-2019) and age, time on the waitlist, and underlying diagnosis as covariates.

RESULTS

The number of patients included were 40,866, of whom 1,387 (3.4%) were classified as ECMO and 39,479 (96.6%) as no ECMO. Average age and initial Lung Allocation Score increased significantly during the study period in both cohorts, but occurred at a slower rate in the ECMO population. The hazard of death was significantly lower in more recent years (2015-2019) for both the ECMO and non-ECMO cohorts (aHR (adjusted hazards ratio) 0.59, 95% confidence interval (CI) 0.37-0.96 and aHR 0.74, 95% CI 0.70-0.79) when compared to the early years (2000-2004) of the study period.

CONCLUSIONS

Post-transplantation survival for patients bridged to transplantation with ECMO demonstrates ongoing improvement despite cannulation of progressively older and sicker patients.

Early experience of a new national lung allocation scheme in the UK based on clinical urgency

INTRODUCTION

A new UK Lung Allocation Scheme (UKLAS) was introduced in 2017, replacing the previous geographic allocation system. Patients are prioritised according to predefined clinical criteria into a three-tier system: the super-urgent lung allocation scheme (SULAS), the urgent lung allocation scheme (ULAS) and the non-urgent lung allocation scheme (NULAS). This study assessed the early impact of this scheme on waiting-list and post-transplant outcomes.

METHODS

A cohort study of adult lung transplant registrations between March 2015 and November 2016 (era-1) and between May 2017 and January 2019 (era-2). Outcomes from registration were compared between eras and stratified by urgency tier and diagnostic group.

RESULTS

During era-1, 461 patients were registered. In era-2, 471 patients were registered (19 (4.0%) SULAS, 82 (17.4%) ULAS and 370 (78.6%) NULAS). SULAS patients were younger (median age 35 vs 50 and 55 for urgent and non-urgent, respectively, p=0.0015) and predominantly suffered from cystic fibrosis (53%) or pulmonary fibrosis (37%). Between eras 1 and 2, the odds of transplantation within 6 months of registration were increased (OR=1.41, 95% CI 1.07 to 1.85, p=0.0142) despite only a 5% increase in transplant activity. Median time-to-transplantation during era-1 was 427 days compared with waiting times in era-2 of 8 days for SULAS, 15 days for ULAS and 585 days for NULAS patients. Waiting-list mortality (15% era-1 vs 13% era-2; p=0.5441) and post-transplant survival at 1 year (81.3% era-1 vs 83.3% era-2; p=0.6065) were similar between eras.

CONCLUSION

The UKLAS scheme prioritises the critically ill and improves transplantation odds. The true impact on waiting-list mortality and post-transplant survival requires further follow-up.

Extracorporeal Life Support in Pulmonary Hypertension: Practical Aspects

Extracorporeal life support (ECLS), in particular veno-arterial extracorporeal membrane oxygenation, has emerged as a potentially life-saving treatment modality in patients presenting with pulmonary hypertension and right heart failure refractory to conventional treatment. Used mainly as a bridge to lung transplantation, ECLS is also being used occasionally as a bridge to recovery in patients with treatable causes of right heart failure. This review article describes indications, contraindications, techniques, and outcomes of the use of ECLS in patients with PH, focusing on practical aspects in the management of such patients.

New OPTN/UNOS data demonstrates higher than previously reported waitlist mortality for lung transplant candidates supported with ECMO

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) is not currently incorporated into US allocation models due to the historical lack of complete data in the national US registry which changed in 2016 to include ECMO at the time of waitlist removal and more granular timing and configuration data.

METHODS

We studied adult lung transplant candidates from May 1, 2016 to June 1, 2020 with data abstracted from multiple sources in the US Scientific Registry of Transplant Recipients. Waitlist analyses included cumulative incidence functions and Cox proportional hazards models considering ECMO as a time-dependent variable. Post-transplant analyses included Kaplan Meier, Cox proportional hazards models, and observed to expected survival ratios.

RESULTS

A total of 867 candidates were on ECMO prior to transplant; 247 were identified using new sources of data. Candidates on ECMO had a 23.9 increased adjusted likelihood of waitlist removal for being too sick or death, but only a 4.08 increased adjusted likelihood of transplant. Candidates bridged with ECMO who underwent lung transplant (N = 587) experienced an increased overall hazard of post-transplant mortality with veno-arterial and veno-venous configurations conferring hazard ratio (HR) = 1.67 (95% CI, 1.16, 2.40), HR = 1.45 (95% CI, 1.15, 1.82), respectively.

CONCLUSIONS

We identified an additional 28.5% of candidates bridged with ECMO prior to transplant using new data. This study of the newly identified full cohort of ECMO candidates demonstrates higher utilization of ECMO as well as an underestimation of waitlist mortality risk factors that should inform strategies to provide timely access to transplants for this population.

Waitlist Mortality and Extracorporeal Membrane Oxygenation Bridge to Lung Transplant

BACKGROUND

Use of extracorporeal membrane oxygenation (ECMO) as bridge to lung transplant has increased. However, little is known about patients placed on ECMO who die while on the waiting list. Using a national lung transplant data set, we investigated variables associated with waitlist mortality of patients bridged to lung transplant.

METHODS

All patients supported on ECMO at time of listing were identified using the United Network for Organ Sharing database. Univariable analyses were performed using bias-reduced logistic regression. Cause-specific hazard models were used to determine the effect of variables of interest on hazard of outcomes.

RESULTS

From April 2016 to December 2021, 634 patients met inclusion criteria. Of these, 445 (70%) were successfully bridged to transplant, 148 (23%) died on the waitlist, and 41 (6.5%) were removed for other reasons. Univariable analysis found associations between waitlist mortality and blood group, age, body mass index, serum creatinine, lung allocation score, days on waitlist, United Network for Organ Sharing region, and being listed at a lower-volume center. Cause-specific hazard models demonstrated that patients at high-volume centers were 24% more likely to survive to transplant and 44% less likely to die on the waitlist. Among patients who were successfully bridged to transplant, there was no difference in survival between low- and high-volume centers.

CONCLUSIONS

ECMO is an appropriate strategy to bridge selected high-risk patients to lung transplant. Of those placed on ECMO with intent to transplant, about one quarter may not survive to transplantation. High-risk patients requiring advanced support strategies may be more likely to survive to transplant when bridged at a high-volume center.

Critical Care Management of the Lung Transplant Recipient

Lung transplantation is often the only treatment option for patients with severe irreversible lung disease. Improvements in donor and recipient selection, organ allocation, surgical techniques, and immunosuppression have all contributed to better survival outcomes after lung transplantation. Nonetheless, lung transplant recipients still experience frequent complications, often necessitating treatment in an intensive care setting. In addition, the use of extracorporeal life support as a means of bridging critically ill patients to lung transplantation has become more widespread. This review focuses on the critical care aspects of lung transplantation, both before and after surgery.

The Lung Transplant Candidate, Indications, Timing, and Selection Criteria

Lung transplantation can be lifesaving for patients with advanced lung disease. Demographics are evolving with recipients now sicker but determining candidacy remains predicated on one's underlying lung disease prognosis, along with the likelihood of posttransplant success. Determining optimal timing can be challenging, and most programs favor initiating the process early and proactively to allow time for patient education, informed decision-making, and preparation. A comprehensive, multidisciplinary evaluation is used to elucidate disease progrnosis and identify risk factors for poor posttransplant outcomes. Candidacy criteria vary significantly by center, and close communication between referring and transplant providers is necessary to improve access to transplant and outcomes.

Minimally Invasive Central Cannulation for Extracorporeal Life Support: The Uniportal and Subxiphoid Approach

OBJECTIVE

Extracorporeal life support (ECLS) for circulatory and/or respiratory failure is improving. Currently, invasive sternotomies or rib-spreading thoracotomies are used for central cannulation of the heart and great vessels. Although peripheral cannulation of the extremities is often used, this approach may result in immobility and unintentional dislodgement. Less invasive methods for central cannulation are needed to achieve long-term ECLS. The objective of this study was to develop 2 different minimally invasive approaches for central thoracic cannulation.

METHODS

Porcine hearts were positioned in a plastic thoracic model. An endoscopic camera and multiple endoscopic instruments were used. Both access points, uniportal (lateral) and subxiphoidal, were simulatively investigated. A novel cannulation method using purse string sutures, a custom-made endoscopic puncture tool, guidewires, and dilator-assisted cannulas was developed. Simulations were tested in a closed circuit regarding leak tightness.

RESULTS

The uniportal approach allowed a cannulation of the aorta, inferior vena cava, right atrium, and main pulmonary artery. Cannulation of the right branches of the pulmonary artery and vein was also possible. From the subxiphoid approach, cannulation of the aorta, main pulmonary artery, and both atria were possible. Subsequent evaluation and leakage tests revealed no damage to the surrounding structures and tightly sealed cannulation sites. The uniportal approach was also successfully performed in a human cadaver to connect the aorta and right atrium with cannulas from the subxiphoidal space.

CONCLUSIONS

Both uniportal and subxiphoid central cannulation of potential sites for ECLS were feasible. This study encourages further investigation and potential clinical translation of minimally invasive central organ support.

Critical Care of the Lung Transplant Patient

Lung transplantation is a therapeutic option for end-stage lung disease that improves survival and quality of life. Prelung transplant admission to the intensive care unit (ICU) for bridge to transplant with mechanical ventilation and extracorporeal membrane oxygenation (ECMO) is common. Primary graft dysfunction is an important immediate complication of lung transplantation with short- and long-term morbidity and mortality. Later transplant-related causes of respiratory failure necessitating ICU admission include acute cellular rejection, atypical infections, and chronic lung allograft dysfunction. Lung transplantation for COVID-19-related ARDS is increasingly common..

Experience with intraoperative extracorporeal membrane oxygenation in lung transplantation: intraoperative indicators

Background/Aim: Intraoperative extracorporeal membrane oxygenation (ECMO) is being used with increasing frequency in lung transplantation. However, the factors associated with the use of intraoperative ECMO in lung transplant patients are not yet conclusive. In this study, we aimed to determine the effective factors for providing intraoperative ECMO support in patients undergoing lung transplantation. In addition, we aimed to evaluate the effect of ECMO support on morbidity and mortality. Methods: In this retrospective cohort study evaluating lung transplant patients, patients were divided into two groups: those who received intraoperative ECMO support and those who did not. Demographic data, the lung allocation score (LAS) and pulmonary arterial pressure (PAP), intraoperative data, postoperative complications, duration of mechanical ventilation (MV), length of stay (LOS) in intensive care and hospital, and mortality rates were recorded for both groups. Factors affecting entry to ECMO were analyzed by Multivariate Logistic Regression. Results: In this period, 51.9% of 87 patients who underwent lung transplantation required intraoperative ECMO. The mean age, LAS, and PAP of the ECMO group were significantly higher than the non-ECMO group (P = 0.043, P = 0.007, and P = 0.007, respectively). In multivariate analysis, it was found that lower MAP averages were a predictive parameter in intraoperative ECMO requirements (OR: 1.091; CI: 1.009-1.179; P = 0.028). The ECMO group’s mechanical ventilation time and hospital mortality were significantly higher than the other group (P = 0.004 and P = 0.025, respectively). Conclusion: Preoperative indicators of intraoperative ECMO support were determined as age, LAS, and PAP elevation. In addition, low MAP levels and high lactate levels were always determined as intraoperative indicators in lung transplantation until the transition to ECMO support.

Awake extracorporeal life support and physiotherapy in adult patients: A systematic review of the literature

OBJECTIVE

The Awake Extracorporeal Life Support (ECLS) practice combined with physiotherapy is increasing. However, available evidence for this approach is limited, with unclear indications on timing, management, and protocols. This review summarizes available literature regarding Awake ECLS and physiotherapy application rates, practices, and outcomes in adults, providing indications for future investigations.

METHODS

Four databases were screened from inception to February 2021, for studies reporting adult Awake ECLS with/without physiotherapy. Primary outcome was hospital discharge survival, followed by Extracorporeal Membrane Oxygenation (ECMO) duration, extubation, Intensive Care Unit stay.

RESULTS

Twenty-nine observational studies and one randomized study were selected, including 1,157 patients (males n = 611/691, 88.4%) undergoing Awake ECLS. Support type was reported in 1,089 patients: Veno-Arterial ECMO (V-A = 39.6%), Veno-Venous ECMO (V-V = 56.8%), other ECLS (3.6%). Exclusive upper body cannulation and femoral cannulation were applied in 31% versus 69% reported cases (n = 931). Extubation was successful in 63.5% (n = 522/822) patients during ECLS. Physiotherapy details were given for 676 patients: exercises confined in bed for 47.9% (n = 324) patients, mobilization until standing in 9.3% (n = 63) cases, ambulation performed in 42.7% (n = 289) patients. Femoral cannulation, extubation and V-A ECMO were mostly correlated to complications. Hospital discharge survival observed in 70.8% (n = 789/1114).

CONCLUSION

Awake ECLS strategy associated with physiotherapy is performed regardless of cannulation approach. Ambulation, as main objective, is achieved in almost half the population examined. Prospective studies are needed to evaluate safety and efficacy of physiotherapy during Awake ECLS, and suitable patient selection. Guidelines are required to identify appropriate assessment/evaluation tools for Awake ECLS patients monitoring.

Managing pulmonary arterial hypertension: how to select and facilitate successful transplantation

PURPOSE OF REVIEW

Despite improvements in available medical therapies, pulmonary arterial hypertension (PAH) remains a progressive, ultimately fatal disorder. Lung transplantation is a viable treatment option for PAH patients with advanced disease.

RECENT FINDINGS

Recent guidelines from the International Society of Heart and Lung Transplantation (ISHLT) have updated recommendations regarding time of referral and listing for lung transplantation in PAH. The new guidelines emphasize earlier referral for transplant evaluation to ensure adequate time for proper evaluation and listing. They also incorporate objective risk stratification criteria to assist in decision-making regarding timing of referral and listing. With regards to the transplant procedure, bilateral lung transplantation has largely supplanted heart-lung transplantation as the procedure of choice for transplantation for advanced PAH. Exceptions to this include patients with PAH because of congenital heart disease and those with concurrent LV dysfunction. Use of mechanical support via venoarterial ECMO initiated before transplantation and continued into the early postoperative period is emerging as a standard of care and may help to reduce early posttransplant mortality in this population. There has been increased recognition of the importance of WHO Group 3 pulmonary hypertension. Many of the lessons learned from PAH may be applied when transplanting patients with severe WHO Group 3 pulmonary hypertension.

SUMMARY

Patients with PAH present unique challenges with regards to transplantation that require a therapeutic approach distinct from other lung disorders. Lung transplantations for PAH are high-risk endeavors best performed at centers with expertise in management of both PAH and extracorporeal support.

Lung transplantation for pulmonary hypertension

From its identification as a distinct disease entity, understanding and management of pulmonary hypertension has continuously evolved. Diagnostic and therapeutic interventions have greatly improved the prognostic implications of this devastating disease, previously rapidly and uniformly fatal to one chronically managed by multi-disciplinary teams. Improved diagnostic algorithms and active research into biochemical signatures of pulmonary hypertension (PH) have led to earlier diagnosis of PH. Medical therapy has moved from upfront use of continuous intravenous prostaglandins to administration of combinations of oral medications targeting multiple pathways underlying this disease process. In addition to improved medical therapies, recently introduced interventions such as pulmonary endarterectomy and pulmonary artery balloon angioplasty for chronic thromboembolic pulmonary hypertension (CTEPH) give patients an increasing array of treatment options. Despite these many advances, lung transplantation remains the definitive treatment for patients with disease refractory to or progressing on best medical therapy. As our understanding of medical therapy has advanced, so to have best practices for lung transplantation. Recipient selection and approach to organ transplantation techniques have continuously evolved. Mechanical circulatory support has become increasingly employed to bridge patients through lung transplantation in the immediate post transplantation recovery. In this review, we give a history of lung transplantation for PH, an overview of PH, discuss current best practices and look to the future for insights into the care of these patients.

Mortality after Lung Transplantation for Children Bridged with Extracorporeal Membrane Oxygenation

RATIONALE

Extracorporeal membrane oxygenation (ECMO) is increasingly used to bridge waitlisted children failing conventional respiratory support to lung transplantation.

OBJECTIVES

To compare in-hospital mortality and a composite outcome of 1-year mortality or re-transplantation in children bridged with ECMO with those on mechanical ventilation (MV), and neither support.

METHODS

The United Network for Organ Sharing (UNOS) was used to analyze lung transplant recipients, aged ≤ 20 y, from January 2004 to August 2019. Recipients were categorized according to level of respiratory support at time of transplant, including ECMO, MV, or neither. Multivariable analysis was used to evaluate support type and in-hospital mortality.

RESULTS

Of 1,014 children undergoing lung transplant, 68 (6.7%) required ECMO as a bridge-to-transplant, 144 (14.2%) MV, and 802 (79.1%) neither. Primary diagnosis in the ECMO cohort included cystic fibrosis (43%), pneumonia/ARDS (10.3%), interstitial pulmonary fibrosis (7.4%) and pulmonary hypertension (5.9%). Number of patients bridged with ECMO increased throughout the study period from none in 2004 to 16.7% in 2018. Multivariable analysis showed bridging with both ECMO (aOR = 3.57; 95% CI: 1.42, 8.97) and MV (aOR = 2.67; 95% CI: 1.26, 5.57) increased in-hospital mortality after lung transplantation. However, there was no difference in composite outcome of mortality and re-transplantation at 1-year between the three groups.

CONCLUSIONS

ECMO to bridge children to lung transplantation has increased. Despite this, ECMO is a high-risk bridge strategy for children awaiting lung transplantation. Future research should target interventions that can be focused on improving survival in these patients.

Lung Transplantation for End-Stage Respiratory Failure After Severe COVID-19: A Report of 2 Cases

We report 2 cases of bilateral lung transplantation for nonresolving coronavirus disease 2019 associated respiratory failure. In the first patient, the severe acute respiratory syndrome coronavirus 2 infection caused acute respiratory distress syndrome requiring prolonged extracorporeal membrane oxygenation support; in the second patient, coronavirus disease 2019 resulted in irreversible pulmonary fibrosis requiring only ventilatory support. The 2 cases represent the 2 ends of the spectrum showing significant differences in preoperative and postoperative courses.

SEDAR/SECCE ECMO management consensus document

ECMO is an extracorporeal cardiorespiratory support system whose use has been increased in the last decade. Respiratory failure, postcardiotomy shock, and lung or heart primary graft failure may require the use of cardiorespiratory mechanical assistance. In this scenario perioperative medical and surgical management is crucial. Despite the evolution of technology in the area of extracorporeal support, morbidity and mortality of these patients continues to be high, and therefore the indication as well as the ECMO removal should be established within a multidisciplinary team with expertise in the area. This consensus document aims to unify medical knowledge and provides recommendations based on both the recent bibliography and the main national ECMO implantation centres experience with the goal of improving comprehensive patient care.

Ambulatory extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation

Ambulatory extracorporeal membrane oxygenation (ECMO) has shown promise as a bridge to lung transplantation. The primary goal of ambulatory ECMO is to provide enough gas exchange to allow patients to participate in preoperative physical therapy. Various strategies of ambulatory ECMO are utilized depending upon patients’ need. A wide spectrum of ECMO configurations is available to tackle this situation. We discuss those configurations in this article.

Effects of the duration of bridge to lung transplantation with extracorporeal membrane oxygenation

Background

Although bridge to lung transplantation (BTT) with extracorporeal membrane oxygenation (ECMO) is increasingly performed, the impact of BTT and its duration on post-transplant outcomes are unclear.

Methods

We retrospectively reviewed medical records of adult patients who underwent lung or heart-lung transplantation in our institution between January 2008 and December 2018. Data were compared in patients who did (n = 41; BTT) and did not (n = 36; non-BTT) require pre-transplant ECMO support. Data were also compared in patients who underwent short-term (<14 days; n = 21; ST-BTT) and long-term (≥14 days; n = 20; LT-BTT) BTTs.

Results

Among 77 patients included, 51 (66.2%) were male and median age was 53 years. The median bridging time in the BTT group was 13 days (interquartile range [IQR], 7–19 days). Although simplified acute physiologic score II was significantly higher in the BTT group (median, 35; IQR, 31–49 in BTT group vs. median, 12; IQR, 7–19 in non-BTT group; p<0.001), 1-year (73.2% vs. 80.6%; p = 0.361) and 5-year (61.5% vs. 61.5%; p = 0.765) post-transplant survival rates were comparable in both groups. Comparison of ST- and LT-BTT subgroups showed that 1-year (90.5% vs. 55.0%; p = 0.009) and 5-year (73.0% vs. 48.1%; p = 0.030) post-transplant survival rates were significantly higher in ST-BTT group. In age and sex adjusted model, the LT-BTT was an independent risk factor for 1-year post-transplant mortality (hazard ratio, 3.019; 95% confidence interval, 1.119–8.146; p = 0.029), whereas the ST-BTT was not.

Conclusions

Despite the severe illness, the BTT group showed favorable post-transplantation outcomes, particularly those bridged for less than 14 days.

Advances in lung transplantation for interstitial lung diseases

PURPOSE OF REVIEW

Lung transplantation (LTx) is increasingly used as ultimate treatment modality in end-stage interstitial lung diseases (ILDs). This review aims to give an overview of the latest evolutions in this field.

RECENT FINDINGS

In the last two years, important new findings regarding LTx outcomes in specific ILD entities have been reported. More data are available on optimization of pre-LTx management of ILD patients especially with regard to pretransplant antifibrotic treatment.

SUMMARY

LTx is the only treatment option with curative intent for ILDs and is increasingly used for this indication. Several studies have now reported adequate outcomes in different ILD entities, although outcome is shown to be affected by underlying telomeropathies. As new studies could not replicate inferior survival with single compared with double LTx, both options remain acceptable. ILD specialists can beneficially impact on post-LTx outcome by optimizing pre-LTx management: corticosteroids should be avoided, antifibrotics should be initiated whenever possible and BMI and nutritional status optimized, rehabilitation and depression-screening strategies should be implemented in all LTx candidates, as these interventions may all improve postlung transplant survival.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant: Considerations for Critical Care Nursing Practice

TOPIC

Candidates waiting for lung transplant are sicker now than ever before. Extracorporeal membrane oxygenation has become useful as a bridge to lung transplant for these critically ill patients.

CLINICAL RELEVANCE

Critical care nurses must be prepared to care for the increasing number of lung transplant patients who require this advanced support method.

PURPOSE OF PAPER

To provide critical care nurses with the foundational knowledge essential for delivering quality care to this high-acuity transplant patient population.

CONTENT COVERED

This review describes the types of extracorporeal membrane oxygenation (venovenous and venoarterial), provides an overview of the indications and contraindications for extracorporeal membrane oxygenation, and discusses the role of clinical bedside nurses in the treatment of patients requiring extracorporeal membrane oxygenation as a bridge to lung transplant.

Lung Transplant from ECMO: Current Results and Predictors of Post-transplant Mortality

Purpose of Review

We examined data from the last 5 years describing extracorporeal life support (ECLS) as a bridge to lung transplantation. We assessed predictors of survival to transplantation and post-transplant mortality.

Recent Findings

The number of lung transplants performed worldwide is increasing. This is accompanied by an increase in the type of patients being transplanted, including sicker patients with more advanced disease. Consequently, there is an increase in the need for bridging strategies, with varying success. Several predictors of failure have been identified. Major risk factors include retransplantation, other organ dysfunction, and deconditioning.

Summary

ECLS is a risky strategy but necessary for patients who would otherwise die if not bridged to transplantation. The presence of predictors for failure is not a contraindication for bridging. However, major risk factors should be approached cautiously. Other, more minor risk factors may be considered acceptable. More importantly, the strategy should be individualized for each patient to achieve the best possible outcomes.

Extracorporeal membrane oxygenation and lung transplantation

The use of extracorporeal membrane oxygenation has had a positive impact on the outcomes after lung transplantation. Extracorporeal membrane oxygenation has a role in all phases of lung transplantation-preoperative, intraoperative, and postoperative periods. It serves as a bridge to transplantation in appropriate patients awaiting lung transplantation. Extracorporeal membrane oxygenation is used as a preferred method of cardiopulmonary support in some centres during implantation; and, after lung transplantation, it can be used to salvage the implanted lung in cases of severe primary graft dysfunction or as a planned extension of intraoperative extracorporeal membrane oxygenation onto the postoperative period. It has now gained acceptance as a mandatory tool in most lung transplant units. This article reviews the history of extracorporeal membrane oxygenation and lung transplantation, their subsequent development, and the current use of extracorporeal membrane oxygenation during lung transplantation. Our institutional practice and experience are described. The implications of the current global coronavirus disease pandemic on extracorporeal membrane oxygenation and lung transplantation are also briefly discussed.

Preoperative risk factors for successful extubation or not after lung transplantation

Background

The purpose of this study was to uncover preoperative risk factors for extubation failure or re-intubation for patients undergoing lung transplant (LTx).

Methods

We performed a retrospective case-control study of LTx from our center between January 2017 and March 2019. Demographic and preoperative characteristics were collected for all included patients. Univariable analysis and multivariable logistic regression were used to analyze risk factors of postoperative unsuccessful extubation following LTx.

Results

Among 107 patients undergoing first LTx investigated, 74 (69.16%) patients who were successfully liberated from mechanical ventilation (MV), and 33 (30.84%) patients who were unsuccessful extubation, which 18 (16.82%) patients suffered from reintubation. associated preoperative factors for unsuccessful extubation following LTx included preoperative extracorporeal membrane oxygenation (ECMO) support [OR =4.631, 95% confidence interval (CI): 1.403–15.286, P=0.012], the preoperative ability of independent expectoration (OR =4.517, 95% CI: 1.498–13.625, P=0.007), the age older than 65-year-old (OR =4.039, 95% CI: 1.154–14.139, P=0.029), and receiving the double lung and heart-LTx (OR =3.390, 95% CI: 0.873–13.162, P=0.078; and OR =16.579, 95% CI: 2.586–106.287, P=0.012, respectively). Further, we investigated the preoperative predicted factors for reintubation. Only the preoperative ECMO remained a significant predictor of re-intubation (OR =4.69, 95% CI: 1.56–15.286, P=0.012).

Conclusions

Preoperative independent sputum clearance, preoperative ECMO, older than 65-year-old, and double lung or heart-LTx were four independent risk factors for unsuccessful extubation. Moreover, preoperative ECMO was the only independent risk factor for reintubation.

Outcome of Bridge to Lung Transplantation With Extracorporeal Membrane Oxygenation in Pediatric Patients 12 Years and Older

BACKGROUND

There is a reluctance to using extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation in the pediatric population. Pediatric patients between ages 12 and 18 years are eligible for acuity-based lung transplantation using the Lung Allocation Score and may be suitable for adult allografts, increasing the donor pool and thus leading to a successful bridge to lung transplantation.

METHODS

The United Network for Organ Sharing dataset was queried for primary lung transplantation in pediatric patients (12-18 years) from 2005 to 2016. Groups were divided into those who were on ECMO (bridged [BG]) and not on ECMO (nonbridged [NBG]) at the time of listing for lung transplant.

RESULTS

The groups comprised 16 BG and 375 NBG patients. Fourteen BG patients (88%) survived the first 30 days. One-year (83.3% vs 86.2%, P = .78) and 3-year (66.7% vs 55.1%, P = .57) survivals were similar in the BG and NBG groups, respectively. Donors in the BG group were more likely to be adults. The median wait-list times were shorter (10.5 [interquartile range {IQR}, 11] vs 93 [IQR, 221] days, P < .001), with a higher Lung Allocation Score (89.8 vs 36.6, P < .001) and similar median ischemic times (5.19 [IQR, 2.32] vs 5.34 [IQR, 1.92] hours, P = .85) in the BG group compared with the NBG group. The median post-transplant length of stay was longer in the BG group (33 [IQR, 31] vs 17 [IQR, 12] days, P = .007) and was the only factor predictive of 3-year mortality. Longer wait-list time had a higher mortality in the BG group.

CONCLUSIONS

ECMO as a bridge to lung transplantation is a reasonable strategy in pediatric patients aged ≥ 12 years with acceptable operative mortality and similar 1- and 3-year survival compared with nonbridged patients despite higher acuity. Bridged patients were more likely to receive adult donor lungs.

Extracorporeal membrane oxygenation as a bridge to lung transplantation in a Turkish lung transplantation program: our initial experience

Lung transplantation is a life-saving treatment for patients with end-stage lung disease. Although the number of lung transplants has increased over the years, the number of available donor lungs has not increased at the same rate, leading to the death of transplant candidates on waiting lists. In this paper, we presented our initial experience with the use of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation. Between December 2016 and August 2018, we retrospectively reviewed the use of ECMO as a bridge to lung transplantation. Thirteen patients underwent preparative ECMO for bridging to lung transplantation, and seven patients successfully underwent bridging to lung transplantation. The average age of the patients was 45.7 years (range, 19–62 years). The ECMO support period lasted 3–55 days (mean, 18.7 days; median, 13 days). In seven patients, bridging to lung transplantation was performed successfully. The mean age of patients was 49.8 years (range 42–62). Bridging time was 3–55 days (mean, 19 days; median, 13 days). Two patients died in the early postoperative period. Five patients survived until discharge from the hospital. One-year survival was achieved in four patients. ECMO can be used safely for a long time to meet the physiological needs of critically ill patients. The use of ECMO as a bridge to lung transplantation is an acceptable treatment option to reduce the number of deaths on the waiting list. Despite the successful results achieved, this approach still involves risks and complications.

What Awaits on the Other Side: Post-Lung Transplant Morbidity and Mortality After Pre-Transplant Hospitalization

Background

Morbidity and mortality rates after lung transplantation remain high compared to other solid organ transplants. In the lung allocation score era, patients given the highest priority on the waitlist are those with the greatest severity of illness, who often require preoperative hospitalization.

Material/Methods

To determine the association of pre-transplant hospitalization with post-transplant outcomes, we retrospectively evaluated 448 lung transplant recipients at our center between January 2010 and July 2017 (114 hospitalized; 334 outpatient).

Results

Survival was similar between the groups (hazard ratio 0.93 [95% CI 0.61 to 1.42], p=0.738). However, hospitalized patients had longer hospital and intensive care unit length of stay compared to outpatients – 25 vs. 18 days, (p<0.001) and 9.5 vs. 6 days, (p<0.001), respectively. Hospitalized patients had higher rates of Grade 3 primary graft dysfunction – 29.8% vs. 9.6%, p<0.001 – and remained mechanically ventilated longer – 6 vs. 3 days, p<0.001. A greater percentage of hospitalized patients needed a tracheostomy and a re-operation within 30 days – 39.5% vs. 15.3% (p<0.001) and 22.8% vs. 12.0% (p=0.005) – respectively. After discharge, 28% of hospitalized patients required acute rehabilitation compared with 12% of outpatients (p=0.001).

Conclusions

While pre-transplant hospitalization is not associated with mortality, it is associated with significant morbidity after transplant.

Chronic Obstructive Pulmonary Disease and Lung Transplantation

Lung transplantation (LTx) has been a viable option for patients with end-stage chronic obstructive pulmonary disease (COPD), with more than 20,000 procedures performed worldwide. Survival after LTx lags behind most other forms of solid-organ transplantation, with median survival for COPD recipients being a sobering 6.0 years. Given the limited supply of suitable donor organs, not all patients with end-stage COPD are candidates for LTx. We discuss appropriate criteria for accepting patients for LTx, as well as contraindications and exclusionary criteria. In the first year post-LTx, infection and graft failure are the leading causes of death. Beyond this chronic graft rejection-currently referred to as chronic lung allograft dysfunction-represents the leading cause of death at all time points, with infection and over time malignancy also limiting survival. Referral of COPD patients to a lung transplant center should be considered in the presence of progressing disease despite maximal medical therapy. As a rule of thumb, a forced expiratory volume in 1 second < 25% predicted in the absence of exacerbation, hypoxia (PaO₂ < 60 mm Hg/8 kPa), and/or hypercapnia (PaCO₂ > 50 mm Hg/6.6 kPa) and satisfactory general clinical condition should be considered the basic prerequisites for timely referral. We also discuss salient issues post-LTx and factors that impact posttransplant survival and morbidity such as infections, malignancy, renal insufficiency, and complications associated with long-term immunosuppression.

Developments in lung transplantation over the past decade

With an improved median survival of 6.2 years, lung transplantation has become an increasingly acceptable treatment option for end-stage lung disease. Besides survival benefit, improvement of quality of life is achieved in the vast majority of patients. Many developments have taken place in the field of lung transplantation over the past decade. Broadened indication criteria and bridging techniques for patients awaiting lung transplantation have led to increased waiting lists and changes in allocation schemes worldwide. Moreover, the use of previously unacceptable donor lungs for lung transplantation has increased, with donations from donors after cardiac death, donors with increasing age and donors with positive smoking status extending the donor pool substantially. Use of ex vivo lung perfusion further increased the number of lungs suitable for lung transplantation. Nonetheless, the use of these previously unacceptable lungs did not have detrimental effects on survival and long-term graft outcomes, and has decreased waiting list mortality. To further improve long-term outcomes, strategies have been proposed to modify chronic lung allograft dysfunction progression and minimise toxic immunosuppressive effects. This review summarises the developments in clinical lung transplantation over the past decade.

Many developments have taken place in lung transplantation over the last decade: indications have broadened, donor criteria expanded, allocations systems changed, and novel therapeutic interventions implemented, leading to improved long-term survivalhttp://bit.ly/2vnpwc1

Contemporary look at extracorporeal membrane oxygenation as a bridge to reoperative lung transplantation in the United States - a retrospective study

The purpose of this study was to examine the influence of extracorporeal membrane oxygenation (ECMO) as a bridge to reoperative lung transplantation (LT) on outcomes and survival. A total of 1960 LT recipients transplanted a second time between 2005 and 2017 were analyzed using the United Network for Organ Sharing (UNOS) Organ Procurement and Transplantation Network (OPTN). Of these recipients, 99 needed ECMO as a bridge to reoperative LT. Mean age was 50 ± 14 years, 47% were females, and the group with ECMO was younger [42 (30-59) vs. 55 (40-62) years]. In both univariate and multivariable analyses (adjusting for age and gender), the ECMO group had greater incidence of prolonged ventilation >48 h (83% vs. 40%, P < 0.001) and in-hospital dialysis (27% vs. 7%, P < 0.001). There were no differences in incidence of acute rejection (15% vs. 11%, P = 0.205), airway dehiscence (4% vs. 2%, P = 0.083), stroke (3% vs. 2%, P = 0.731), or reintubation (20% vs. 20%, P = 0.998). Kaplan-Meier survival analysis showed the ECMO group had reduced 1-year survival (66.6% vs. 83.0%, P < 0.001). After covariate adjustment, the ECMO group only had increased risk for 1-year mortality in the 2005-2011 era (HR = 2.57, 95% CI = 1.45-4.57, P = 0.001). For patients who require reoperative LT, bridging with ECMO was historically a significant predictor of poor outcome, but may be improving in recent years.

Contemporary analysis of charges and mortality in the use of extracorporeal membrane oxygenation: A cautionary tale

Objective

The use of extracorporeal membrane oxygenation (ECMO) has increased exponentially. Costs and outcomes, however, vary considerably by indication. We sought to elucidate and quantify these differences.

Methods

Adult patients supported on ECMO between 2008 and 2016 were analyzed using the Nationwide Inpatient Sample. We divided the study period into an early (2008-2013) and late period (2013-2016). The primary outcome was hospital charges, and the secondary outcomes were mortality, length of stay (LOS), and duration of ECMO support. These were stratified by the 5 most common indications: postcardiotomy shock (PCS), cardiogenic shock (CS), severe acute respiratory failure (SARF), heart (HT), and lung transplantation (LT). Both patient and hospital characteristics were assessed. Charges were adjusted for inflation and analyzed using a generalized linear model with gamma distribution. Pairwise comparison with Bonferroni correction was used to evaluate the cost and multivariate logistic regression to assess the risk of mortality.

Results

Data pertaining to 15,829 adult patients were evaluated. Mean age of the entire cohort was 52.8 years, 8895 (56%) were white, and 10,278 (65%) were male. PCS was the predominant indication for ECMO (39%), followed by CS (37%). SARF accounted for 15% and HT and LT accounted for 3.9% and 5.4%, respectively. Mean LOS and duration of ECMO support were 23.4 days and 5.3 days respectively. Mean hospital charges per hospitalization for the entire cohort were USD 731,914 per patient. Charges per patient pertaining to hospitalizations in which ECMO was used in transplant patients were the highest: USD 1,448,931 and USD 1,574,378 (P = .99) for HT and LT, respectively. Charges were lower for the other indications: PCS USD 798,909, CS USD 655,099, and SARF USD 824,852. Overall mortality for the entire cohort was 55%. PCS and CS (53% vs 58%, P = .34) had similar survival, whereas SARF was 45%, LT was 39% and HT 32%. There were no differences in survival in these latter indications (SARF, LT and HT). The cumulative charges (proportion × hospital charges) reveal that PCS and CS (39% and 37%) account for both the majority of charges as well as the greatest mortality. Conversely, SARF and transplantation accounted for the smaller proportion of charges and the lower mortality. Patients undergoing HT had the longest LOS (51.7 days) and duration on ECMO (15.9 days), followed by LT (35.4 and 8.8 days respectively), and patients with SARF (28.6 and 6.6 respectively). LOS and duration of ECMO for those with PCS were 18.7 days and 4.8 days, respectively. Those on ECMO for CS were hospitalized for 19.7 days and spent an average of 3.8 days on ECMO. Mortality decreased, whereas charges increased in the late era.

Conclusions

The use of ECMO is associated with high hospital charges and a wide variation in outcomes. Hospitalizations, in which ECMO is used to support patients with cardiogenic shock (PCS and CS), are individually associated with lower LOS and charges. Cumulatively, however, these account for greater charges and greater mortality. Although mortality may be decreasing, overall charges are increasing with time. These variations may influence reimbursement decisions in value-based healthcare.

Extracorporeal membrane oxygenation support in adult patients with acute respiratory distress syndrome

Introduction: The global number of patients receiving extracorporeal membrane oxygenation (ECMO) support has been growing after several studies highlighted the favorable results attained in cases of severe respiratory failure. However, evidence-based guidelines for optimal use of ECMO are lacking.Areas covered: This review covers optimal candidates, timing of initiation, strategies for patient management including mechanical ventilation, and decision-making regarding discontinuation of ECMO based on its potential role in treatment of patients with acute respiratory distress syndrome.Expert opinion: Early initiation of ECMO should be considered if hypoxemia and uncompensated hypercapnia do not respond to optimal conventional treatment. Use of a comprehensive management approach for preventing additional lung injury and extrapulmonary organ failure is critical during ECMO support to ensure the best outcome. The possibility of weaning from ECMO should be fully assessed by a multidisciplinary team during ECMO support. Futility should not be determined solely by duration of ECMO, and use of prolonged ECMO for lung recovery may be worthwhile.

Lung transplantation for cystic fibrosis

BACKGROUND

The contribution of lung transplantation to the treatment of patients with end-stage cystic fibrosis (CF) has been debated. We aimed to describe achievable outcomes from high-volume CF and lung transplant programs. This study reports on the largest single-center experience of lung transplantation for adult and pediatric patients with CF. It also highlights the evolution of practice and outcomes over time.

METHODS

A retrospective analysis of the prospectively collected Toronto Lung Transplant database was carried out. Post-transplant survival in CF was calculated using the Kaplan-Meier method and analyzed with log-rank tests.

RESULTS

From 1983 to 2016, a total of 1,885 transplants were performed at our institution, where 364 (19.3%) were CF recipients and another 39 (2.1%) were CF retransplants. The mean age at first transplant was 29.5 ± 9.7 years where 56.6% were males and 91.5% were adults. Pre-transplantation, 88 patients (24.2%) were Burkholderia cepacia complex (BCC)-positive, 143 (39.3%) had diabetes mellitus, and the mean forced expiratory volume in one second was 26.0 ± 7.2%, as predicted at listing. The 1-, 5-, and 10-year probabilities of survival in adults who were BCC-negative were 94%, 70%, and 53%, respectively. Pediatric, BCC-positive, and retransplant recipients had worse survival than adult patients who were BCC-negative. Strategies to improve the donor pool did not affect survival but possibly reduced waitlist mortality. For the entire cohort, the most common causes of death after lung transplant were infection and chronic lung allograft dysfunction.

CONCLUSIONS

Lung transplantation for CF provides excellent short- and long-term outcomes. These results strongly support lung transplantation as the standard of care for patients with CF having advanced lung disease.

Extracorporeal membrane oxygenation as a bridge to lung transplantation: analysis of Korean organ transplantation registry (KOTRY) data

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation has greatly increased. However, data regarding the clinical outcomes of this approach are lacking. The objective of this multicenter prospective observational cohort study was to evaluate lung transplantation outcomes in Korean Organ Transplantation Registry (KOTRY) patients for whom ECMO was used as a bridge to transplantation.

METHODS

Between March 2015 and December 2017, a total of 112 patients received lung transplantation and were registered in the KOTRY, which is a prospective, multicenter cohort registry. The entire cohort was divided into two groups: the control group (n = 85, 75.9%) and bridge-ECMO group (n = 27, 24.1%).

RESULTS

There were no significant differences in pre-transplant and intraoperative characteristics except for poorer oxygenation, more ventilator use, and longer operation time in the bridge-ECMO group. The prevalence of primary graft dysfunction at 0, 24, 48, and 72 h after transplantation did not differ between the two groups. Although postoperative hospital stays were longer in the bridge-ECMO group than in the control group, hospital mortality did not differ between the two groups (25.9% vs. 13.3%, P = 0.212). The majority of patients (70.4% of the bridge-ECMO group and 77.6% of the control group) were discharged directly to their homes. Finally, the use of ECMO as a bridge to lung transplantation did not significantly affect overall survival and graft function.

CONCLUSIONS

Short- and long-term post-transplant outcomes of bridge-ECMO patients were comparable to recipients who did not receive ECMO.

Extracorporeal Membrane Oxygenation in the Perioperative Care of the Lung Transplant Patient

Lung transplantation (LT) is definitive therapy for end-stage lung disease. Donor allocation based on medical urgency has led to an increased trend in the transplantation of sicker and older patients. Mechanical ventilation (MV) formerly was the only method of bridging high-acuity patients to LT. When the physiological demands of ventilatory support exceeds the capability of MV, extracorporeal membrane oxygenation (ECMO) may become necessary. Recent improvements in ECMO technology and component design have led to a resurgence of interest in its use before, during, and after LT. Survival with ECMO as a bridge to LT has improved over time, now with many centers reporting little or no difference in outcomes, and some even reporting better outcomes, as compared with MV. Extracorporeal life support may also be used intraoperatively. In many studies to date, ECMO or cardiopulmonary bypass (CPB) has been reserved for patients who became hemodynamically unstable during the procedure or patients who could not tolerate single-lung ventilation. Both methods of support are fraught with potential complications. However, multiple studies comparing ECMO with CPB have shown that intraoperative use of ECMO resulted in improved outcomes and overall survival as well as lower rates of bleeding complications. In order to further reduce complications associated with ECMO, planned intraoperative ECMO use is occasionally reserved for high-risk patients who might otherwise require CPB. Future studies will need to improve patient selection to fully take advantage of the use of ECMO in LT while minimizing its costs.