Extracorporeal membrane oxygenation as a bridge to lung transplant: midterm outcomes

Extracorporeal membrane oxygenation as a bridge to lung transplantation: 5-year outcomes and bridge to decision in a large, older cohort

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (BTT) has expanded considerably, though evidence-based selection criteria and long-term outcome data are lacking. The purpose of this study was to evaluate whether risk factors often used to exclude patients from ECMO BTT-specifically older age and not yet being listed for transplant-are validated by long-term outcomes.

METHODS

To ensure minimum 5-year follow-up, a retrospective cohort study was performed of adult patients actively listed for lung transplantation at a high-volume center and bridged on ECMO between January 2012 and December 2017. Data was collected through January 1, 2023.

RESULTS

Among 50 patients bridged on ECMO, 25 survived to transplant. Median age at listing was 58 (interquartile range [IQR], 42-65) in the transplanted group and 65 (IQR, 56.5-69) in the deceased group (P = 0.051). One-year, 3-year, and 5-year survival were 88% (22/25), 60% (15/25), and 44% (11/25), respectively, with eight patients still living at the time of review. Median time spent at home during the year post-transplant was 340 days (IQR, 314-355). Older age at listing was a negative predictor of survival on ECMO to transplant (odds ratio 0.92 [95% confidence interval, 0.86-0.99], P = 0.01). Thirteen patients were placed on ECMO prior to being listed and three were listed the same day as ECMO cannulation, with 10/16 transplanted. No significant difference in post-transplant survival was found between patients placed on ECMO prior to listing (n = 10) and those already listed (n = 15) (P = 0.93, log-rank). Serial post-transplant spirometry up to 5 years and surveillance transbronchial biopsy demonstrated good allograft function and low rates of cellular rejection.

CONCLUSIONS

In one of the oldest cohorts of ECMO BTT patients described, favorable survival outcomes and allograft function were observed up to 5 years irrespective of whether patients were previously listed or bridged to decision. Despite inherent limitations to this retrospective, single-center study, the data presented support the feasibility of ECMO BTT in older and not previously listed advanced lung disease patients.

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.

A novel nomogram for predicting prolonged mechanical ventilation in lung transplantation patients using extracorporeal membrane oxygenation

Prolonged mechanical ventilation (PMV) is commonly associated with increased post-operative complications and mortality. Nevertheless, the predictive factors of PMV after lung transplantation (LTx) using extracorporeal membrane oxygenation (ECMO) as a bridge remain unclear. The present study aimed to develop a novel nomogram for PMV prediction in patients using ECMO as a bridge to LTx. A total of 173 patients who used ECMO as a bridge following LTx from January 2022 to June 2023 were divided into the training (122) and validation sets (52). A mechanical ventilation density plot of patients after LTx was then performed. The training set was divided in two groups, namely PMV (95) and non-prolonged ventilation (NPMV) (27). For the survival analysis, the effect of PMV was assessed using the log-rank test. Univariate and multivariate logistic regression analyses were performed to assess factors associated with PMV. A risk nomogram was established based on the multivariate analysis, and model performance was further assessed in terms of calibration, discrimination, and clinical usefulness. Internal validation was additionally conducted. The difference in survival curves in PMV and NPMV groups was statistically significant (P < 0.001). The multivariate analysis and risk factors in the nomogram revealed four factors to be significantly associated with PMV, namely the body mass index (BMI), operation time, lactic acid at T0 (Lac), and driving pressure (DP) at T0. These four factors were used to develop a nomogram, with an area under the curve (AUC) of 0.852 and good calibration. After internal validation, AUC was 0.789 with good calibration. Furthermore, goodness-of-fit test and decision-curve analysis (DCA) indicated satisfactory performance in the training and internal validation sets. The proposed nomogram can reliably and accurately predict the risk of patients to develop PMV after LTx using ECMO as a bridge. Four modifiable factors including BMI, operation time, Lac, and DP were optimized, which may guide preventative measures and improve prognosis.

Lung Re-transplantation after prolonged veno-venous extracorporeal membrane oxygenation (ECMO) in a child with chronic lung allograft dysfunction

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) may be used as a bridge to lung transplantation in selected patients with end-stage respiratory failure. Historically, ECMO use in this setting has been associated with poor outcomes Puri V et.al, J Thorac Cardiovasc Surg, 140:427. More recently, technical advances and the implementation of rehabilitation and ambulation while awaiting transplantation on ECMO have led to improved surgical and post-transplant outcomes Kirkby S et.al, J Thorac Dis, 6:1024.

METHODS

We illustrate the case of a 6-year-old child who received prolonged ECMO support as a bridge to lung re-transplantation secondary to Chronic Lung Allograft Dysfunction (CLAD).

RESULTS

Early rehabilitation was key in improving the overall pre-transplant conditioning during ECMO.

CONCLUSIONS

Despite challenges associated with awake/ambulatory ECMO, the use of this strategy as a bridge to lung transplantation is feasible and has resulted in improved pre-transplant conditioning and post-transplant outcomes.

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.

Update on Lung Transplantation for Cystic Fibrosis

Lung transplantation provides a treatment option for many individuals with advanced lung disease due to cystic fibrosis (CF). Since the first transplants for CF in the 1980s, survival has improved and the opportunity for transplant has expanded to include individuals who previously were not considered candidates for transplant. Criteria to be a transplant candidate vary significantly among transplant programs, highlighting that the engagement in more than one transplant program may be necessary. Individuals with highly resistant CF pathogens, malnutrition, osteoporosis, CF liver disease, and other comorbidities may be suitable candidates for lung transplant, or if needed, multi-organ transplant. The transplant process involves several phases, from discussion of prognosis and referral to a transplant center, to transplant evaluation, to listing, transplant surgery, and care after transplant. While the availability of highly effective CF transmembrane conductance regulator (CFTR) modulators for many individuals with CF has improved lung function and slowed progression to respiratory failure, early discussion regarding transplant as a treatment option and referral to a transplant program are critical to maximizing opportunity and optimizing patient and family experience. The decision to be evaluated for transplant and to list for transplant are distinct, and early referral may provide a treatment option that can be urgently executed if needed. Survival after transplant for CF is improving, to a median survival of approximately 10 years, and most transplant survivors enjoy significant improvement in quality of life.

Outcomes of Venovenous Extracorporeal Membrane Oxygenation in Viral Acute Respiratory Distress Syndrome

Our study assessed the relationship between the duration of venovenous extracorporeal membrane oxygenation (V-V ECMO) and patient outcomes. We studied patients undergoing V-V ECMO support for acute respiratory distress syndrome (ARDS) between 2009 and 2017 who were reported to the Extracorporeal Life Support Organization registry. We evaluated survival, major bleeding, renal failure, pulmonary complications, mechanical complications, neurologic complications, infection, and duration of V-V ECMO support. Multivariable regression modeling assessed risk factors for adverse events. Of the 4,636 patients studied, the mean support duration was 12.2 ± 13.7 days. There was a progressive increase in survival after the initiation of V-VECMO, peaking at a survival rate of 73% at 10 days of support. However, a single-day increase in V-V ECMO duration was associated with increased bleeding events (odds ratio [OR] 1.038; 95% confidence interval [CI]: 1.029-1.047; p < 0.0001), renal failure (OR 1.018; 95% CI: 1.010-1.027; p < 0.0001), mechanical complications (OR 1.065; 95% CI: 1.053-1.076; p < 0.0001), pulmonary complications (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001), and infection (OR 1.04; 95% CI: 1.03-1.05; p < 0.0001). V-V ECMO progressively increases survival for ARDS over the first 10 days of support. Thereafter, rising complications associated with prolonged durations of support result in a progressive decline in survival.

Recipient Management before Lung Transplantation

Lung transplantation is considered a viable treatment option for patients with end-stage lung disease. Recent decades have seen a gradual increase in the number of lung transplantation patients worldwide, and in South Korea, the case number has increased at least 3-fold during the last decade. Furthermore, the waiting list time is becoming longer, and more elderly patients (>65 years) are undergoing lung transplantation; that is, the patients placed on the waiting list are older and sicker than in the past. Hence, proper management during the pre-transplantation period, as well as careful selection of candidates, is a key factor for transplant success and patient survival. Although referring and transplant centers should address many issues, the main areas of focus should be the timing of referral, nutrition, pulmonary rehabilitation, critical care (including mechanical ventilation and extracorporeal membrane oxygenation), psychological support, and the management of preexisting comorbid conditions (coronary artery disease, diabetes mellitus, gastroesophageal reflux disease, osteoporosis, malignancy, viral infections, and chronic infections). In this context, the present article reviews and summarizes the pre-transplantation management strategies for adult patients listed for lung transplantation.

Spirometry testing for extracorporeal membrane oxygenation (ECMO) bridge to transplant patients

PURPOSE

ECMO can provide a bridge to transplantation and improve survival for patients with advanced lung disease. Although pulmonary function testing (PFT) is an important component of the lung allocation score (LAS), it is not always feasible on patients requiring ECMO. While generally safe, PFT testing has contraindications and is not recommended in unstable patients. Currently there are no recommendations regarding the performance of spirometry in ECMO patients.

STUDY DESIGN

and Methods: We reviewed data on five patients with advanced lung disease requiring ECMO-bridge to transplant. After careful consideration of the theoretical physiologic risks associated with forced expiratory maneuvers, bedside spirometry was performed in order to update the patients' LAS.

RESULTS

All patients successfully completed three forced expiratory maneuvers in the seated position with a bedside spirometer. Vital signs and ECMO flow were stable during testing and without complication. In 2 patients who had both a LAS pre and post spirometry, the LAS increased by 3-5 points.

CONCLUSION

Spirometry results are pivotal to organ allocation under current organ sharing protocols. This case series demonstrates that bedside spirometry testing may be performed safely in patients on ECMO awaiting lung transplantation without appreciable side effects, leading to a more accurate LAS score.

Venoarterial Versus Venovenous Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation

BACKGROUND

Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) has been used as a bridge to lung transplantation with acceptable outcomes. We hypothesized that VA ECMO, as part of a multidisciplinary ECMO program, yields similar outcomes as VV ECMO as a bridge in lung transplantation.

METHODS

Records of all patients who had undergone ECMO with the intention to bridge to lung transplantation at University of California Los Angeles from January 1, 2012 to March 31, 2020 were reviewed. Baseline characteristics, in-hospital outcomes, long-term survival, and freedom from bronchiolitis obliterans syndrome (BOS) were assessed.

RESULTS

During this interval, 58 patients were placed on ECMO with the intention to bridge to lung transplantation: 27 on VV ECMO, and 31 on VA ECMO with a median duration of 7 and 17 days of support, respectively(p=0.01). Successful bridge to lung transplantation occurred in 21(78%) VV and 26(84%) VA patients. Incidence of primary graft dysfunction III(PGD III) at 72 hours in the VV and the VA cohorts were 0% and 4%, respectively(p=0.99). In-hospital and 90-day survival of the VV and VA groups were 100% and 96%, respectively(p=0.99). Three-year survival of the two groups were not significantly different from a contemporary cohort of lung transplant recipients not bridged with ECMO.

CONCLUSIONS

VA and VV ECMO can both be used as a bridge to lung transplantation with high success, with short and medium-term survival similar to non-bridged lung transplant recipients. Both modes should be considered effective at bridging select candidates to lung transplantation.

Lung transplantation for post-COVID-19 pulmonary fibrosis

COVID-19 has affected over a billion people around the world, with over 2 million losing their lives (Worldometer). About 10% of patients infected with COVID-19 develop a serious illness, including respiratory failure, that require advanced life-supporting measures. Mortality among this subgroup exceeds 60%. We present a case of an otherwise healthy 34-year-old male who developed end-stage pulmonary fibrosis following COVID-19 infection. He achieved haemodynamic stability with mechanical ventilation and extracorporeal membrane oxygenation (ECMO) but did not show any sign of weaning off ECMO; however, he successfully underwent bilateral lung transplantation.

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.

Membrane Lung and Blood Pump Use During Prolonged Extracorporeal Membrane Oxygenation: Trends From 2002 to 2017

Extracorporeal life support (ECLS) has grown in its application since its first clinical description in the 1970s. The technology has been used to support a wide variety of mechanical support modalities and diseases, including respiratory failure, cardiorespiratory failure, and cardiac failure. Over many decades and safety and efficacy studies, followed by randomized clinical trials and thousands of clinical uses, ECLS is considered as an accepted treatment option for severe pulmonary and selected cardiovascular failure. Extracorporeal life support involves the use of support artificial organs, including a membrane lung and blood pump. Over time, changes in the technology and the management of ECLS support devices have evolved. This manuscript describes the use of membrane lungs and blood pumps used during ECLS support from 2002 to 2017 in over 65,000 patients reported to the Extracorporeal Life Support Organization Registry. Device longevity and complications associated with membrane lungs and blood pump are described and stratified by age group: neonates, pediatrics, and adults.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary technology capable of supporting cardiac and respiratory function in the presence of end-stage lung disease. Initial experiences using ECMO as a bridge to lung transplant (ECMO-BTLT) were characterized by high rates of ECMO-associated complications and poor posttransplant outcomes. More recently, ECMO-BTLT has garnered success in preserving patients' physiologic condition and candidacy prior to lung transplant due to technological advances and improved management. Despite recent growth, clinical practice surrounding use of ECMO-BTLT remains variable, with little data to inform optimal patient selection and management. Although many questions remain, the use of ECMO-BTLT has shown promising outcomes suggesting that ECMO-BTLT can be an effective strategy to ensure that complex and rapidly decompensating patients with end-stage lung disease can be safely transplanted with good outcomes. Further studies are needed to refine and inform practice patterns, management, and lung allocation in this high-risk and fragile patient population.

Lung transplantation for the treatment of irreversible acute respiratory distress syndrome

BACKGROUND

Despite advances in critical care for acute respiratory distress syndrome (ARDS), some survivors in the acute phase are unable to wean from extracorporeal membrane oxygenation (ECMO) or mechanical ventilation. To date, little is known regarding whether lung transplantation confers a survival benefit for irreversible ARDS.

METHODS

This retrospective study was conducted using the United Network for Organ Sharing database (May 2005-December 2018). Patients with restrictive lung disease were divided into two groups: patients with and without ARDS. Propensity score matching identified recipients without ARDS for the control group.

RESULTS

A total of 63 patients with ARDS were waitlisted for lung transplantation, while 39 received a lung transplant after a median waitlist duration of 8 days. Seventy-eight patients were matched as controls. In the ARDS group, the median age was 30 years, and the median lung allocation score was 88.4. Among the 39 recipients, 30 (76.9%) received ECMO support prior to transplantation. Lung transplantation for ARDS and restrictive lung disease showed similar 90-day (87.2% vs. 88.5%, p = .80), 1-year (82.1% vs. 85.9%, p = .52), and 3-year (69.2% vs. 65.4%, p = .94) survival rates.

CONCLUSIONS

Lung transplantation provides acceptable outcomes in selected patients with irreversible ARDS.

Extracorporeal membrane oxygenation as a bridge vs. non-bridging for lung transplantation: A systematic review and meta-analysis

Whether extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (BTT) can achieve a similar survival to non-BTT remains controversial. We conducted this meta-analysis to compare the outcomes between ECMO BTT and non-BTT to facilitate better clinical decision-making. Seven databases were searched for eligible studies comparing ECMO BTT and non-BTT. The primary endpoints included survival, intraoperative indicators, postoperative hospitalization indicators, and postoperative complications. Nineteen studies (involving 7061 participants) were included in the final analysis. The outcomes of overall survival, overall survival rate, graft survival rate, in-hospital mortality, postoperative hospital days, postoperative intensive care unit days, postoperative ventilation time, blood transfusion volume, and postoperative complications were all better in the non-BTT group. The total mortality in ECMO bridging was 23.03%, in which the top five causes of death were right heart failure (8.03%), multiple organ failure (7.03%), bleeding (not cranial) (4.67%), cranial bleeding (3.15%), and sepsis (2.90%). In summary, Non-BTT is associated with better survival and fewer complications compared to BTT. When ECMO may be the only option, the patient and medical team need to realize the increased risk of ECMO by complications and survival.

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.

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.

Timing it right: the challenge of recipient selection for lung transplantation

Selection criteria for the referral and potential listing of patients for lung transplantation (LTx) have changed considerably over the last three decades but one key maxim prevails, the ultimate focus is to increase longevity and quality of life by careful utilization of a rare and precious resource, the donor organs. In this article, we review how the changes have developed and the outcomes of those changes, highlighting the impact of the lung allocation score (LAS) system. Major diseases, including interstitial lung disease (ILD), chronic obstructive pulmonary disease and pulmonary hypertension are considered in detail as well as the concept of retransplantation where appropriate. Results from bridging to LTx using extracorporeal membrane oxygenation (ECMO) are discussed and other potential contraindications evaluated such as advanced age, frailty and resistant infections. Given the multiplicity of risk factors it is a credit to those working in the field that such excellent and improving results are obtained with an ongoing dedication to achieving best practice.

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.

An Incidental Finding at Transplant Assessment: Case Report

A 43-year-old woman with chronic hypersensitivity pneumonitis was referred for lung transplant assessment. An echocardiogram as part of her work-up revealed a large left atrial myxoma, presenting a conundrum on how best to manage her combined pathology. Because of the level of pulmonary disease, early intervention to remove the myxoma was not thought be viable without postoperative support. Use of extracorporeal membrane oxygenation to bridge patients for lung transplant is feasible, yet risks increased perioperative mortality. We present the first reported case of simultaneous cardiac myxoma removal and lung transplant.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplantation in the United States: A Multicenter Survey

The clinical use of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (LTx) has greatly increased in recent years. However, clinical practices for ECMO as a bridge to LTx vary widely between LTx centers. To better define the current practice of ECMO as a bridge to LTx, we surveyed pre-LTx ECMO practices among all adult LTx programs in the United States. All US LTx centers were surveyed (n = 57) between January and December 2014. Responses were received from 33 of 57 centers (58%). Of 33 responding centers, six (18%) performed ≥50 LTxs per year (defined as high volume) and two (6%) performed <10 LTxs per year (low volume). Two-third of responding centers, 22/33 (67%), reported use of ECMO as a bridge to LTx. Of these 22 centers, 18 (82%) successfully used venovenous (VV) ECMO as a bridge to LTx using the dual-lumen Avalon cannula. Patient >65 years of age was judged an ECMO contraindication in 15/33 (45%) of responding centers, but 12/33 (36%) centers, including the six high-volume centers, had no official age cutoff for ECMO candidacy. There was no consensus on the maximum acceptable duration of pre-LTx ECMO therapy; although 18/33 (55%) of programs had no defined maximal duration of ECMO pre-LTx, 10/33 (30%) considered >10 days on ECMO support contraindicated. Our survey suggests that in the United States, ECMO is used frequently pre-LTx, particularly VV ECMO at high-volume centers. However, criteria for ECMO initiation, age eligibility, bedside care, and maximum duration of support varied significantly between survey respondents.

Twenty-year experience with extracorporeal life support as bridge to lung transplantation

OBJECTIVES

Extracorporeal life support is increasingly used to bridge deteriorating candidates to lung transplantation. Nevertheless, only few systematic reports with a limited number of patients exist describing this practice and its changes over time.

METHODS

We retrospectively reviewed our institutional database and performed an era analysis to identify trends over time and risk factors for mortality. After applying propensity score matching, outcomes of bridged patients were compared with those of standard lung transplantation recipients.

RESULTS

Extracorporeal life support was used in 120 patients as an intention to bridge to lung transplantation. Eleven patients (9.2%) were bridged between 1998 and 2004, 39 patients (32.5%) were bridged between 2005 and 2010, and 70 patients were bridged (58.3%) between 2010 and 2017. In the first era, the main bridging modality was venoarterial-extracorporeal membrane oxygenation (n = 10, 90.9%), whereas venovenous devices were primarily used in later eras (second era: n = 18, 46.2%; third era: n = 39, 55.8%). In the second and third eras, 9 patients (23.1%) and 24 patients (34.3%) could be bridged awake. Short-term outcome was poor in the first era, with only 36.4% of patients discharged alive but improved in later eras (53.8% and 77.1%; P = .002). Extracorporeal life support-bridged patients showed an impaired short-term outcome compared with standard recipients. However, survival conditional on 90 days did not differ among the groups (P = .178). In univariate and multivariate analyses, awake extracorporeal life support was protective for survival, whereas acute retransplantation was a risk factor for mortality.

CONCLUSIONS

Over the past 2 decades, the role of extracorporeal life support bridging evolved from an acute rescue therapy to a semi-elective procedure. Stratified outcome analysis revealed that extracorporeal life support bridging yielded similar long-term survival compared with nonbridged patients.

Outcomes of Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (BTT) has become a critical component of caring for patients with end-stage lung disease. This study examined outcomes of patients who received ECMO as a BTT.

METHODS

Statistical analysis was performed on data gathered retrospectively from the electronic medical records of adult patients who received ECMO as BTT at Columbia University Medical Center from April 2009 through July 2018.

RESULTS

A total of 121 adult patients were placed on ECMO as BTT, and 70 patients (59%) were successfully bridged to lung transplantation. Simplified Acute Physiology Score II, unplanned endotracheal intubation, renal replacement therapy, and cerebrovascular accident were identified as independent predictors of unsuccessful BTT. Ambulation was the only independent predictor of successful BTT (odds ratio, 7.579; 95% confidence interval, 2.158 to 26.615; p = 0.002). Among the 64 patients (91%) who survived to hospital discharge, survival was 88% at 1 year and 83% at 3 years. Propensity matching between BTT and non-BTT lung transplant recipients did not show a significant difference in survival (log-rank = 0.53) despite significant differences in the lung allocation score (median, 92.2 [interquartile range, 89.0 to 94.2] vs 49.6 [interquartile range, 40.6 to 72.3], p < 0.01).

CONCLUSIONS

ECMO can be used successfully to bridge patients with end-stage lung disease to lung transplantation. When implemented by an experienced team with adherence to stringent protocols and patient selection, outcomes in BTT patients were comparable to patients who did not receive pretransplant support.

Lung Transplantation as a Therapeutic Option in Acute Respiratory Distress Syndrome

BACKGROUND

Lung transplantation (LTPL) is considered as a salvage therapeutic option in patients with end-stage lung disease. However, there is a lack of sufficient data on the use of LTPL in patients with acute respiratory distress syndrome (ARDS). Although there are few case reports on lung transplant for ARDS, no case series exists up to date. The aim of this study was to evaluate the clinical outcomes of patients with ARDS in accordance with the LTPL status.

METHODS

Patients who had severe ARDS (PaO2/FiO2 ratio ≤ 100 mm Hg with positive end-expiratory pressure ≥ 5 cm H2O) and were listed for LTPL with no underlying end-stage lung disease were included in this single-center retrospective study. Demographic and clinical data of the patients were collected and analyzed.

RESULTS

Fourteen patients were listed for LTPL due to severe ARDS. All patients received mechanical ventilation, and 12 (86%) patients underwent extracorporeal membrane oxygenation. Of the 9 patients who underwent LTPL, 8 (89%) survived, whereas only 1 (20%) patient out of those who did not receive LTPL survived. The median survival time of the patients who underwent LTPL was 1996 days (interquartile range [IQR], 872-2239), compared with 49 days (IQR, 872-2239) in patients who did not undergo LTPL. The median survival time after LTPL was 64 months (IQR, 28-72). The 3-year survival rate of the recipients was 78%.

CONCLUSIONS

LTPL may be considered as a therapeutic option in a select group of patients with severe ARDS. However, the irreversibility of the patient's lung status should be considered.

Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Acute exacerbation (AEx) of idiopathic pulmonary fibrosis (IPF) is a clinically important complication of IPF that carries a high morbidity and mortality. In the last decade we have learned much about this event, but there are many remaining questions: What is it? Why does it happen? How can we prevent it? How can we treat it? This chapter attempts to summarize and update our current understanding of the epidemiology, etiology, and management of acute exacerbation of IPF and point out areas where additional data are needed.

Extracorporeal support, during and after lung transplantation: the history of an idea

During recent years, continuous technological innovation has provoked an increase of extracorporeal life support (ECLS) use for perioperative cardiopulmonary support in lung transplantation. Initial results were disappointing, due to ECLS-specific complications and high surgical risk of the supported patients. However, the combination of improved patient management, multidisciplinary team work and standardization of ECLS protocols has recently yielded excellent results in several case series from high-volume transplant centres. Therein, it was demonstrated that, although the prevalence of complications remains higher in supported patients, there may be no difference in long-term graft function between supported and non-supported patients. These results are important, because most of the patients who require ECLS support in lung transplantation are young and have no other chance to survive, but to be transplanted. Moreover, there is no device for "bridging to destination" therapy in lung transplantation. Of note, the evidence in favour of ECLS support in lung transplantation was never validated by randomized controlled trials, but by everyday experience at the patient bed-side. Here, we review the state-of-the-art ECLS evidence for intraoperative and postoperative cardiopulmonary support in lung transplantation.

Historical perspectives of lung transplantation: connecting the dots

Lung transplantation is now a treatment option for many patients with end-stage lung disease. Now 55 years since the first human lung transplant, this is a good time to reflect upon the history of lung transplantation, to recognize major milestones in the field, and to learn from others' unsuccessful transplant experiences. James Hardy was instrumental in developing experimental thoracic transplantation, performing the first human lung transplant in 1963. George Magovern and Adolph Yates carried out the second human lung transplant a few days later. With a combined survival of only 26 days for these first 2 lung transplant recipients, the specialty of lung transplantation clearly had a long way to go. The first "successful" lung transplant, in which the recipient survived for 10.5 months, was reported by Fritz Derom in 1971. Ten years later, Bruce Reitz and colleagues performed the first successful en bloc transplantation of the heart and one lung with a single distal tracheal anastomosis. In 1988, Alexander Patterson performed the first successful double lung transplant. The modern technique of sequential double lung transplantation and anastomosis performed at the mainstem bronchus level was originally described by Henri Metras in 1950, but was not reintroduced into the field until Pasque reported it again in 1990. Since then, lung transplantation has seen landmark changes: evolving immunosuppression regimens, clarifying the definition of primary graft dysfunction (PGD), establishing the lung allocation score (LAS), introducing extracorporeal membrane oxygenation (ECMO) as a bridge to transplant, allowing donation after cardiac death, and implementing ex vivo perfusion, to name a few. This article attempts to connect the historical dots in this field of research, with the hope that our effort helps summarize what has been achieved, and identifies opportunities for future generations of transplant pulmonologists and surgeons alike.

Blood Products Transfusion and Mid-Term Outcomes of Lung Transplanted Patients Under Extracorporeal Membrane Oxygenation Support

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is considered a reliable technique in lung transplantation requiring cardiorespiratory support. However, the impact of this technology on blood product transfusion rate and outcomes compared to off-pump lung transplantation has been rarely investigated.

METHODS

Between January 2012 and June 2015, 52 elective adult lung transplants were performed at our institution. Of these, 15 recipients required intraoperative venoarterial extracorporeal support and 37 did not. We compared blood product consumption and other outcome variables between the 2 groups.

RESULTS

We found comparable in-hospital (86.7% vs 97.3%, P = .14) and 6-month (86.7% vs 91.9%, P = .56) survival between patients with and without extracorporeal support, respectively. Survival at 30 days was lower in the ECMO group (86.7% vs 100%, P = .02). Although patients who underwent ECMO received more intraoperative transfusions, postoperative transfusion rate was similar between the 2 groups. The ECMO group experienced longer mechanical ventilation (median 3 vs 2 days, P = .02) and intensive care unit stay (median 7 vs 5 days, P = .02), besides more cardiogenic shock and deep vein thrombosis. However, we observed no difference in other major and minor in-hospital complications and 6-month complications.

CONCLUSIONS

In our experience, despite the higher need for intraoperative transfusions, lung transplantation performed with ECMO support is comparable to the off-pump procedure as to short-term survival and outcomes.

Increasing Opportunity for Lung Transplant in Interstitial Lung Disease With Pulmonary Hypertension

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation for end-stage interstitial lung disease (ILD) and pulmonary hypertension (PH) has varying results based on ECMO configuration. We compare our experience using venovenous (VV) and venoarterial (VA) ECMO bridge to transplantation for ILD with PH on survival to successful transplantation.

METHODS

A single-center retrospective review was done of patients with ILD and secondary PH who were placed on either VV or VA ECMO as bridge to transplantation from 2010 to 2016. Comparisons for factors associated with survival to transplantation between VV and VA ECMO strategies were made using Cox proportional hazards model. Subgroup analysis included comparisons of VV ECMO patients who remained on VV or were converted to VA ECMO.

RESULTS

A total of 50 patients with ILD and PH were treated initially with either VV (n = 19) or VA (n = 31) ECMO as bridge to lung transplantation. Initial VA ECMO had a significantly higher survival to transplantation compared with initial VV ECMO (p = 0.03). Cox proportional hazards modeling showed a 59% reduction in risk of death for VA compared with VV ECMO (hazard reduction 0.41, 95% confidence interval: 0.18 to 0.92, p = 0.03). Patients converted from VV to VA ECMO had significantly longer survival awaiting transplant than patients who remained on VV ECMO (p = 0.03). Ambulation on ECMO before transplantation was associated with an 80% reduction in the risk of death (hazard reduction 0.20, 95% confidence interval: 0.08 to 0.48, p < 0.01).

CONCLUSIONS

Venoarterial ECMO upper body configuration for patients with end stage ILD and PH significantly improves overall survival to transplantation.

Mechanical Ventilation and Extracorporeal Membrane Oxygenation as a Bridging Strategy to Lung Transplantation: Significant Gains in Survival

Mechanical ventilation (MV) and extracorporeal membrane oxygenation (ECMO) are increasingly used to bridge patients to lung transplantation. We investigated the impact of using MV, with or without ECMO, before lung transplantation on survival after transplantation by performing a retrospective analysis of 826 patients who underwent transplantation at our high-volume center. Recipient characteristics and posttransplant outcomes were analyzed. Most lung transplant recipients (729 patients) did not require bridging; 194 of these patients were propensity matched with patients who were bridged using MV alone (48 patients) or MV and ECMO (49 patients). There was no difference in overall survival between the MV and MV+ECMO groups (p = 0.07). The MV+ECMO group had significantly higher survival conditioned on surviving to 1 year (median 1,811 days ([MV] vs. not reached ([MV+ECMO], p = 0.01). Recipients in the MV+ECMO group, however, were more likely to require ECMO after lung transplantation (16.7% MV vs. 57.1% MV+ECMO, p < 0.001). There were no differences in duration of postoperative MV, hospital stay, graft survival, or the incidence of acute rejection, renal failure, bleeding requiring reoperation, or airway complications. In this contemporary series, the combination of MV and ECMO was a viable bridging strategy to lung transplantation that led to acceptable patient outcomes.

Safety and Feasibility of Early Physical Therapy for Patients on Extracorporeal Membrane Oxygenator: University of Maryland Medical Center Experience

OBJECTIVES

To examine the feasibility and safety of mobilizing patients while on extracorporeal membranous oxygenation support.

DESIGN

Retrospective cohort study.

SETTING

Medical and Surgical ICUs in a large tertiary care hospital in the United States.

PATIENTS

Adults supported on extracorporeal membranous oxygenation from January 2014 to December 2015.

MEASUREMENTS AND MAIN RESULTS

We reviewed the medical records from physical therapy, perfusion, and intensivists to obtain the number and type of physical therapy interventions and discharge status; extracorporeal membranous oxygenation type and description of support, cannulation sites; and risk management details of adverse effects, if any. Of 254 patients supported on extracorporeal membranous oxygenation, 167 patients (66.7%) received a total of 607 physical therapy sessions while on extracorporeal membranous oxygenation support. In this cohort, 134 patients (80.2%) had at least one femoral cannula during physical therapy intervention. Sixty-six of the 167 patients (39.5%) were supported on extracorporeal membranous oxygenation with bifemoral cannulas, and 44 (26.3%) were on veno-arterial extracorporeal membranous oxygenation. A dual lumen catheter was only used in five cases. Twenty-five patients (15%) (13 bifemoral cases) participated in standing or ambulation activities. Seventy-five patients (68.8%) who were successfully weaned from extracorporeal membranous oxygenation were discharged to a rehabilitation facility; 26 patients (23.8%) went home. Three minor events (< 0.5%) involving two episodes of arrhythmias and a hypotension event interrupted the therapy sessions, but mobility activities and exercises resumed that day. No major events were reported.

CONCLUSIONS

With a highly trained multidisciplinary team and a focus on restoring function, it is feasible and safe to deliver early rehabilitation including standing and ambulation to patients on extracorporeal membranous oxygenation support even those with femoral cannulation sites with veno-arterial extracorporeal membranous oxygenation and veno-venous extracorporeal membranous oxygenation.

Extracorporeal membrane oxygenation versus cardiopulmonary bypass during lung transplantation: a meta-analysis

BACKGROUND

We reviewed the available literature on patients undergoing lung transplantation supported by cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO).

METHODS

A systematic literature search was performed in three databases, in accordance with the PRISMA guidelines. Meta-analyses were used to compare the outcomes of ECMO and CPB procedures.

RESULTS

Seven observational studies met the inclusion criteria incorporating 785 patients. ECMO support showed lower rate of primary graft dysfunction, bleeding, renal failure requiring dialysis, tracheostomy, intraoperative transfusions, intubation time, and hospital stay. Total support time was greater for the ECMO-supported group. No difference was reported between operative and ischemic time.

CONCLUSIONS

The present study indicates that the intraoperative use of ECMO is associated with increased efficacy and safety, regarding short-term outcomes, compared to CPB. Well-designed, randomized studies, comparing ECMO to CPB, are necessary to assess their clinical outcomes further.

Center Volume and Extracorporeal Membrane Oxygenation Support at Lung Transplantation in the Lung Allocation Score Era

RATIONALE

Outcomes related to extracorporeal membrane oxygenation (ECMO) used to bridge patients to lung transplantation in the context of center differences in transplant expertise have not been investigated.

OBJECTIVES

To determine the effects of ECMO at time of transplant on survival in adult patients who underwent transplant surgery in historically low- and high-volume centers.

METHODS

The United Network for Organ Sharing database was used to classify centers according to transplant volume between May 2005 and May 2010 as low-volume centers (bottom 50% of centers), medium-volume centers (next 25%), or high-volume centers (top 25%). Influences of ECMO on post-transplant survival were estimated among adults receiving lung transplants between June 2010 and June 2015 based on historic center volume in the preceding 5 years.

MEASUREMENTS AND MAIN RESULTS

Sixty-five centers were classified according to lung transplant volume in 2005-2010, with 8,228 adults (279 on ECMO) who underwent transplants at these centers between June 2010 and June 2015 included in the survival analysis. In multivariable Cox analysis stratified by center, we found that, in historically low-volume centers, ECMO was associated with increased post-transplant mortality hazard (hazard ratio, 1.968; 95% confidence interval, 1.083-3.577; P = 0.026). In contrast, in historically high-volume centers, ECMO had no adverse influence on post-transplant survival (hazard ratio, 0.853; 95% confidence interval, 0.596-1.222; P = 0.386).

CONCLUSIONS

An adverse effect of ECMO at the time of lung transplant was evident in low-volume centers but absent in centers with experience of performing more than 170 lung transplants in the first 5 years of the lung allocation score era.