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

Venous thromboembolism following lung transplantation

Lung transplantation (LT) is currently a surgical therapy option for end-stage lung disease. Venous thromboembolism (VTE), which can occur after LT, is associated with significant morbidity and mortality. Because of improved outcomes, increasing numbers of patients are receiving LT as treatment. Patients on the waitlist for LT tend to be older with weakness and frailty in addition to pulmonary symptoms. These factors contribute to a heightened risk of postoperative VTE. Furthermore, patients who clinically deteriorate while on the waitlist may require extra corporeal membrane oxygenation as a bridge to LT. Bleeding and thromboembolism are common in these patients. Pulmonary embolism (PE) in a freshly transplanted lung can have significant effects leading to morbidity and mortality. PE typically leads to impairment of gas exchange and right ventricular strain. In LT, PE can affect healing of bronchial anastomosis and may even contribute to the development of chronic allograft lung dysfunction. This article discussed the incidence, clinical features and diagnosis of VTE after LT. Furthermore, the treatment modalities, complications, and outcomes of VTE were reviewed.

Early outcomes of lung transplantation under the composite allocation score system

PURPOSE

The Composite Allocation Score was introduced in March 2023 with the goal of improving organ allocation for potential lung transplant recipients. The purpose of this study is to characterize waitlist and post-transplant outcomes for adult lung transplant recipients under the Composite Allocation Score policy.

METHODS

We included all adult candidates listed for isolated lung transplantation in the United States from May 2022 to December 2023. Candidates were categorized into 2 eras: Era 1 (pre-Composite Allocation Score, May 15, 2022 to March 8, 2023) and Era 2 (post--Composite Allocation Score, March 9, 2023 to December 31, 2023). Waitlist mortality and transplant rates within 9 months of listing were compared using competing risk regression. Post-transplant outcomes of the 2 groups were also compared. Kaplan-Meier was used to evaluate 9-month survival post-transplant.

RESULTS

A total of 5293 candidates were listed, with 2744 (51.8%) during Era 2. Lung transplant candidates in Era 2 experienced lower waitlist mortality (sub-hazard ratio, 0.79; 95% CI, 0.69-0.92, P = .002) and higher transplant rates (sub-hazard ratio, 1.22; 95% CI, 1.15-1.28, P < .001) compared with those in Era 1. Post-transplant extracorporeal membrane oxygenation rates at 72 hours (11.1% vs 9.9%, P = .25) and 30-day mortality (2.3% vs 2.4%, P = .96) were similar between Era 2 and Era 1. Nine-month survival after transplantation was not significantly different between Era 2 and Era 1 recipients (91.7% vs 90.9%, P = .47).

CONCLUSIONS

Lung transplant candidates in Era 2 had lower waitlist mortality and higher transplant rates compared with Era 1, with similar 9-month post-transplant survival. These findings suggest that the Composite Allocation Score policy has contributed to allocation improvement without compromising early post-transplant outcomes.

Extracorporeal membrane oxygenation as a bridge to thoracic multiorgan transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has emerged as a crucial tool in the care of patients with multiorgan failure and is increasingly utilized as a bridge to transplantation. While data on ECMO as a bridge to isolated heart and lung transplantation have been described, our emerging experience with ECMO as a bridge to thoracic multiorgan transplantation is not yet well understood.

METHODS

The United Network for Organ Sharing database was used to identify adult patients undergoing thoracic multiorgan transplantation between 1987 and 2022. Exclusion criteria were recipient age <18 and bridging with other non-ECMO mechanical circulatory support, Survival analysis was performed to compare outcomes between patients bridged to transplantation with ECMO and those who were not bridged.

RESULTS

Of 3,927 patients undergoing thoracic multiorgan transplantation, a total of 203 (5.2%) patients received ECMO as a bridge to transplantation. Among ECMO recipients, patients were most commonly bridged to heart-lung (45.8%), followed by heart-kidney (34.5%), and lung-kidney transplantation (11.8%). At a median follow-up of 35.5 months, unadjusted survival among patients bridged with ECMO was decreased versus multiorgan transplant recipients who were not bridged (p < 0.001). Among patients surviving past 30 days following transplantation, conditional long-term survival was similar between ECMO and non-ECMO patients (p = 0.82).

CONCLUSIONS

ECMO is increasingly utilized as a bridge to thoracic multiorgan transplantation and is associated with increased 30 day mortality and decreased long-term survival. In select patients surviving to 30 days following transplantation, similar long-term survival is seen between patients bridged with ECMO and those not bridged.

[Extracorporeal Life Support in Lung Transplantation and Beyond]

Lung transplantation is often the sole and final therapeutic option for patients with end-stage lung disease. In recent years, clinical outcomes have steadily improved, driven in part by advancements in extracorporeal mechanical support. These techniques have become an integral component of routine clinical practice, particularly in lung transplantation centres. Extracorporeal lung support systems range from relatively simple pumpless devices to complex cannulation techniques and device configurations. In particular, extracorporeal membrane oxygenation (ECMO) encompasses various configurations widely utilised in thoracic surgery, especially in lung transplantation. A distinction can be made between preoperative ECMO, referred to as bridge-to-transplant, and intraoperative ECMO support, which is employed during the transplantation procedure. In recent years, intraoperative ECMO has largely replaced the traditional heart-lung machine. Additionally, ECMO plays a critical role in the immediate postoperative period, both in preventing and managing primary graft dysfunction. Beyond lung transplantation, extracorporeal life support systems are also applied in complex thoracic surgical resections and procedures involving the central airways. In the future, technical advancements and improvements in treatment protocols are expected to further enhance the role of extracorporeal mechanical support in the management of thoracic surgical patients.

Respiratory compliance related to prognostic of lung transplant patients with veno‑venous extracorporeal membrane oxygenation support

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) plays an important role in the perioperative care of critically ill lung transplant patients. However, the factors predicting prognosis are unclear. This study assessed the association between static respiratory compliance (Crs) and outcomes of lung transplant patients receiving VV-ECMO in terms of 90-day mortality. Data were retrospectively collected for patients that underwent lung transplantation with VV-ECMO support during 2022-2023. Patients were divided into two groups according to the early postoperative Crs: lower Crs (Crs < 25 ml/cmH2O) and higher Crs (Crs ≥ 25 ml/cmH2O). Differences in patient characteristics and prognosis were then compared between the two groups. Receiver operating characteristic (ROC) curve analysis was used to evaluate the value of Crs for predicting 90-day mortality and univariate Cox proportional hazard model analysis was performed to estimate risk of Crs. Data were available for a total of 85 patients, including 50 (58.8%) patients in the higher Crs group and 35 (41.2%) patients in the lower Crs group. A lower Crs was significantly associated with a longer postoperative ECMO duration (hours, 42 vs. 24; P = 0.022), longer postoperative ventilator time (days, 3.7 vs. 2.0; P = 0.003), higher application of continuous renal replacement therapy (CRRT) (20.0% vs. 6.0%; P = 0.049), higher incidence of pneumonia (42.9% vs. 20.0%; P = 0.023), and higher 90-day mortality (22.9% vs. 6.0%; P = 0.023). The area under the curve of Crs for predicting 90-day mortality was 0.661 (P = 0.034). A higher Crs was a protective factor (hazard ratio = 0.925 [0.870-0.984)] P = 0.014). For lung transplant patients receiving VV-ECMO support, Crs < 25 ml/cmH2O is associated with more complications and higher 90-day mortality. As Crs is easily obtained at the bedside, it may be useful for predicting prognosis and guiding patient management.

The role of extracorporeal membrane oxygenation in thoracic anesthesia

PURPOSE OF REVIEW

Circulatory and respiratory support with extracorporeal membrane oxygenation (ECMO) has gained widespread acceptance during high-end thoracic surgery. The purpose of this review is to summarize the recent knowledge and give an outlook for future developments.

RECENT FINDINGS

A personalized approach of ECMO use is state of the art for monitoring during surgery. Personalization is increasingly applied during anesthesia for high-end surgery nowadays. This is reflected in the point of care testing (POCT) for anticoagulation and cardiac function during surgery on ECMO combining specific patient data into tailored algorithms. For optimizing protective ventilation MP (mechanical power) is a promising parameter for the future. These personalized methods incorporating numerous patient data are promising for the improvement of morbidity and mortality in high-end thoracic surgery. However, clinical data supporting improvement are not available to date but can be awaited in the future.

SUMMARY

Clinical practice during surgery on ECMO is increasingly personalized. The effect of personalization on morbidity and mortality must be examined in the future. Undoubtedly, an increase in knowledge can be expected from this trend towards personalization.

Improved Results Over Time With Bridge-to-Lung Transplantation: A 10-Year Experience of a Single High-Volume Center

When donor scarcity limits timely lung transplantation (LTx), extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation (BTT) can prolong survival and delay deconditioning until the donor lungs become available. We reviewed 10-year BTT experiences of a single high-volume center, where 99 (59%) were on ECMO BTT among 169 eligible adult LTx cases. Both 28-day and 2-year survivals did not differ between BTT and non-BTT. The BTT data was then divided into two periods, delineated by the most recent 3 years. The clinical outcomes of the earlier period ("Period 1") and the later period ("Period 2") were compared, and mortality within 28 days of LTx was significantly lower in Period 2 (n = 1, 1.7%) than in Period 1 (n = 6, 14.6%, p < 0.01). Improved survival was observed in the subgroup with BTT duration of 14 days or more. Taken together, more experiences in BTT and improved competence may contribute to better survival after LTx, especially in patients receiving ECMO for 14 days or more.

Extracorporeal membrane oxygenation for adults with respiratory failure secondary to cardiorespiratory disease: evolving indications and clinical practice

Extracorporeal membrane oxygenation (ECMO) can support patients with severe cardiorespiratory failure presenting with hypoxia who would otherwise have not survived. Patient selection for ECMO is challenging and relies on the integration of physiological variables with an assessment of reversibility of the underlying condition or suitability for transplantation. In this review, we focus on patients with cardiorespiratory disease who may present with severe hypoxia. We will discuss the indications and contraindications for ECMO; the evidence for ECMO, which is limited to a small number of clinical trials and registry data; the complications of ECMO; expanding technologies and indications; the development of a multidisciplinary ECMO network; and future research. The aim is to increase knowledge of this important area for respiratory physicians.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights from 2024

This special article is the 17th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor in chief, Dr Kaplan, and the editorial board for the opportunity to continue this series, namely, the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology.1 The major themes selected for 2024 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2024 begin with an update on perioperative rehabilitation and enhanced recovery in cardiothoracic surgery, with a focus on novel methods to best assess our patients in the preoperative period and the impact of implementing enhanced recovery care models on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into anemia, transfusions, and coronary artery bypass grafting outcomes with a focus on gender disparities. The third theme is focused on cardiothoracic transplantation, with discussions focusing on techniques related to lung transplantation, including mechanical circulatory support. The 4th theme is focused on mechanical circulatory support, with discussions exploring advancements in left ventricular assist devices highlight the evolving landscape of mechanical circulatory support and discussion of anticoagulation practices. The fifth and final theme is an update on medical cardiology, with a focus on the outcomes of transcatheter management of regurgitant pathology, device management in heart failure, and new techniques in catheter ablation. The themes selected for this article are only a few of the diverse advances in the specialty during 2024. These highlights will inform the reader of key updates on a variety of topics, leading to improvement in perioperative outcomes for patients with cardiothoracic and vascular disease.

ECMO for bridging lung transplantation

BACKGROUND

With the shift in donor lung allocation from blood type and waiting order to the use of the lung allocation score (LAS) system, there are increasingly more cases of ECMO bridging lung transplantation. However, there are still some problems in case selection, implementation, and management.

METHODS

We analyzed and summarized a series of data on ECMO bridging lung transplantation through an extensive literature review.

RESULTS

The improvement of the lung transplant allocation system and the progress of ECMO technology have made the ECMO bridge to lung transplant more widely used in clinical practice. The selection of bridge patients is a crucial link in the success of transplantation, and accurate assessment of the patient before transplantation is necessary. The advantages and disadvantages of different bridge strategies exist, and the appropriate bridge strategy should be selected based on the patient's situation. Bleeding and thrombosis complications often occur during ECMO circulation, and there is currently no optimal anticoagulation strategy. The predictive score for bridge post-outcome is still subject to certain limitations.

CONCLUSIONS

ECMO bridging lung transplantation is suitable for patients waiting for lung transplantation when other respiratory support is ineffective or when hemodynamic instability occurs the disease is severe and the donor organ is easily obtainable. Patients aged 65 years or older, or have reversible multiple organ dysfunction should not be included as contraindications for ECMO bridging lung transplantation.

Enhancing lung transplantation with ECMO: a comprehensive review of mechanisms, outcomes, and future considerations

BACKGROUND

Lung transplantation (LTx) is a critical intervention for patients with end-stage lung disease. However, challenges such as donor organ scarcity and post-transplant complications significantly affect its success. Recent advancements in Extracorporeal Membrane Oxygenation (ECMO) have shown promise in improving the outcomes and expanding eligibility for LTx.

METHODS

A comprehensive literature review was conducted, focusing on studies that explore the use of ECMO in lung transplantation. A thorough search of relevant studies on ECMO and LTx was conducted using multiple scholarly databases and relevant keywords, resulting in 73 studies that met the inclusion criteria. Sources included peer-reviewed journals and clinical trial results, with emphasis on articles captured recent advancements in ECMO technology and techniques.

RESULTS

ECMO has been crucial in supporting patients before, during, and after LTx. It serves as a bridge to transplantation by maintaining pulmonary and circulatory stability in critically ill patients awaiting donor organs. ECMO also aids in the evaluation of marginal donor lungs and supports patients through acute post-transplant complications. Recent technological advancements have improved the safety and efficacy of ECMO, further solidifying its role in LTx.

CONCLUSION

In conclusion, this review underscores ECMO's critical role in enhancing outcomes across all stages of lung transplantation. Its various configurations and strategies have shown promise in stabilizing critically ill patients and improving transplant success rates. Looking ahead, it's important to gather more information about the long-term outcomes and potential complications associated with ECMO use. More research and data collection will help us understand the benefits and risks better, leading to improved decision-making and patient care in this field.

ISHLT consensus statement on the perioperative use of ECLS in lung transplantation: Part II: Intraoperative considerations

The use of extracorporeal life support (ECLS) throughout the perioperative phase of lung transplantation requires nuanced planning and execution by an integrated team of multidisciplinary experts. To date, no multidisciplinary consensus document has examined the perioperative considerations of how to best manage these patients. To address this challenge, this perioperative utilization of ECLS in lung transplantation consensus statement was approved for development by the International Society for Heart and Lung Transplantation Standards and Guidelines Committee. International experts across multiple disciplines, including cardiothoracic surgery, anesthesiology, critical care, pediatric pulmonology, adult pulmonology, pharmacy, psychology, physical therapy, nursing, and perfusion, were selected based on expertise and divided into subgroups examining the preoperative, intraoperative, and postoperative periods. Following a comprehensive literature review, each subgroup developed recommendations to examine via a structured Delphi methodology. Following 2 rounds of Delphi consensus, a total of 39 recommendations regarding intraoperative considerations for ECLS in lung transplantation met consensus criteria. These recommendations focus on the planning, implementation, management, and monitoring of ECLS throughout the entire intraoperative period.

Which strategy is better for lung transplantation: Cardiopulmonary bypass or extracorporeal membrane oxygenation?

Background: In lung transplantation surgery, extracorporeal life support (ECLS) is essential for safety. Various support methods, including cardiopulmonary bypass (CPB) and off-pump techniques, are used, with extracorporeal membrane oxygenation (ECMO) gaining prominence. However, consensus on the best support strategy is lacking.Purpose: This article reviews risks, benefits, and outcomes of different support strategies in lung transplantation. By consolidating knowledge, it aims to clarify selecting the most appropriate ECLS modality.Research Design: A comprehensive literature review examined CPB, off-pump techniques, and ECMO outcomes in lung transplantation, including surgical results and complications.Study Sample: Studies, including clinical trials and observational research, focused on ECLS in lung transplantation, both retrospective and prospective, providing a broad evidence base.Data Collection and/or Analysis: Selected studies were analyzed for surgical outcomes, complications, and survival rates associated with CPB, off-pump techniques, and ECMO to assess safety and effectiveness.Results: Off-pump techniques are preferred, with ECMO increasingly vital as a bridge to transplant, overshadowing CPB. However, ECMO entails hidden risks and higher costs. While safer than CPB, optimizing ECMO postoperative use and monitoring is crucial for success.Conclusions: Off-pump techniques are standard, but ECMO's role is expanding. Despite advantages, careful ECMO management is crucial due to hidden risks and costs. Future research should focus on refining ECMO use and monitoring to improve outcomes, emphasizing individualized approaches for LT recipients.