Outcomes of intraoperative venoarterial extracorporeal membrane oxygenation versus cardiopulmonary bypass during lung transplantation

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.

Pediatric Lung Transplantation for Pulmonary Vascular Diseases: Recent Advances and Challenges

Pediatric lung transplantation for pulmonary vascular diseases has seen notable advancements and trends. Medical therapies, surgical options, and bridging techniques like extracorporeal membrane oxygenation and different forms of transplants have expanded treatment possibilities. Current challenges include ensuring patient adherence to post-transplant therapies, addressing complications like primary graft dysfunction and rejection, and conducting further research in less common conditions like pulmonary veno-occlusive disease and pulmonary vein stenosis. In this review article, the authors will explore the advancements, emerging trends, and persistent challenges in pediatric lung transplantation for pulmonary vascular diseases.

Randomized trial of routine versus on-demand intraoperative extracorporeal membrane oxygenation in lung transplantation: A feasibility study

In most centers, extracorporeal membrane oxygenation (ECMO) is the preferred means to provide cardiopulmonary support during lung transplantation. However, there is controversy about whether intraoperative venoarterial (VA) ECMO should be used routinely or selectively. A randomized controlled trial is the best way to address this controversy. In this publication, we describe a feasibility study to assess the practicality of a protocol comparing routine versus selective VA-ECMO during lung transplantation. This prospective, single-center, randomized controlled trial screened all patients undergoing lung transplantation. Exclusion criteria include retransplantation, multiorgan transplantation, and cases where ECMO is mandatory. We determined that the trial would be feasible if we could recruit 19 participants over 6 months with less than 10% protocol violations. Based on the completed feasibility study, we conclude that the protocol is feasible and safe, giving us the impetus to pursue a multicenter trial with little risk of failure due to low recruitment.

Impact of anticoagulation intensity on blood transfusion for venoarterial extracorporeal membrane oxygenation during lung transplantation

Venoarterial extracorporeal membrane oxygenation is increasingly used for mechanical circulatory support during lung transplant. Optimal intensity of intraoperative anticoagulation would be expected to mitigate thromboembolism without increasing bleeding and blood product transfusions. Yet, the optimal intensity of intraoperative anticoagulation is unknown. We performed a retrospective cohort study of 163 patients who received a bilateral lung transplant at a single center. We categorized the intensity of anticoagulation into 4 groups (very low to high) based on the bolus dose of unfractionated heparin given during lung transplant and compared the rates of intraoperative blood transfusions and the occurrence of thromboembolism between groups. When compared to the very low-intensity group, each higher intensity group was associated with higher red blood cell, fresh frozen plasma, and platelet transfusions. The occurrence of thromboembolism was similar across groups. These preliminary data suggest that lower intensity anticoagulation may reduce the rate of intraoperative blood transfusions, although further study is needed.

Heparin-free veno-arterial extracorporeal membrane oxygenation in lung transplantation: a retrospective cohort study

BACKGROUND

In lung transplantation (LTx) surgery, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide mechanical circulatory support to patients with cardiopulmonary failure. However, the use of heparin in the administration of ECMO can increase blood loss during LTx. This study aimed to evaluate the safety of heparin-free V-A ECMO strategies.

METHODS

From September 2019 to April 2022, patients who underwent lung transplantation at the First Affiliated Hospital of Guangzhou Medical University were retrospectively reviewed. A total of 229 patients were included, including 117 patients in the ECMO group and 112 in the non-ECMO group.

RESULT

There was no significant difference in the incidence of thrombus events and bleeding requiring reoperation between the two groups. The in-hospital survival rate after single lung transplantation (SLTx) was 81.08%in the ECMO group and 85.14% in the Non-ECMO group, (P = 0.585). The in-hospital survival rate after double lung transplantation (DLTx) was 80.00% in the ECMO group and 92.11% in the Non-ECMO groups (P = 0.095).

CONCLUSIONS

In conclusion, the findings of this study suggest that the heparin-free V-A ECMO strategy in lung transplantation is a safe approach that does not increase the incidence of perioperative thrombotic events or bleeding requiring reoperation.

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.

Donor and recipient risk factors for the development of primary graft dysfunction following lung transplantation

Primary Graft Dysfunction (PGD) is a major cause of both short-term and long-term morbidity and mortality following lung transplantation. Various donor, recipient, and technical risk factors have been previously identified as being associated with the development of PGD. Here, we present a comprehensive review of the current literature as it pertains to PGD following lung transplantation, as well as discussing current strategies to mitigate PGD and future directions. We will pay special attention to recent advances in lung transplantation such as ex-vivo lung perfusion, thoracoabdominal normothermic regional perfusion, and up-to-date literature published in the interim since the 2016 ISHLT consensus statement on PGD and the COVID-19 pandemic.

Intraoperative Extracorporeal Support during Lung Transplantation: Not Just for the High-Risk Patient

The use of intraoperative mechanical support during lung transplantation has traditionally been a controversial topic. Trends for intraoperative mechanical support strategies swing like a pendulum. Historically, cardiopulmonary bypass (CPB) was the modality of choice during transplantation. It provides full hemodynamic support including oxygenation and decarboxylation. Surgical exposure is improved by permitting the drainage of the heart and provides more permissive retraction. CPBs contain drainage reservoirs with hand-held pump suction catheters promoting blood conservation through collection and re-circulation. But CPB has its disadvantages. It is known to cause systemic inflammation and coagulopathy. CPB requires high doses of heparinization, which increases bleeding risks. As transplantation progressed, off-pump transplantation began to trend as a preferable option. ECMO, however, has many of the benefits of CPB with less of the risk. Outcomes were improved with ECMO compared to CPB. CPB has a higher blood transfusion requirement, a higher need for post-operative ECMO support, a higher re-intubation rate, high rates of kidney injury and need for hemodialysis, longer ICU stays, higher incidences of PGD grade 3, as well as overall in-hospital mortality when compared with ECMO use. The focus now shifts to using intraoperative mechanical support to protect the graft, helping to reduce ischemia-reperfusion injury and allowing for lung protective ventilator settings. Studies show that the routine use of ECMO during transplantation decreases the rate of primary graft dysfunction and many adverse outcomes including ventilator time, need for tracheostomy, renal failure, post-operative ECMO requirements, and others. As intraoperative planned ECMO is considered a safe and effective approach, with improved survival and better overall outcomes compared to both unplanned ECMO implementation and off-pump transplantation, its routine use should be taken into consideration as standard protocol.

The Evaluation and Management of Coronary Artery Disease in the Lung Transplant Patient

Lung transplantation can greatly improve quality of life and extend survival in those with end-stage lung disease. In order to derive the maximal benefit from such a procedure, patients must be carefully selected and be otherwise healthy enough to survive a high-risk surgery and sometimes prolonged immunosuppressive therapy following surgery. Patients therefore must be critically assessed prior to being listed for transplantation with close attention paid towards assessment of cardiovascular health and operative risk. One of the biggest dictators of this is coronary artery disease. In this review article, we discuss the assessment and management of coronary artery disease in the potential lung transplant candidate.

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.

Innovative use of Protek Duo during bilateral lung transplant with Veno-Arterial Extracorporeal Membrane Oxygenation assistance

V-A ECMO during bilateral lung transplantation is routinely used when extracorporeal support is needed, in particular in case of patients affected by pulmonary hypertension. We report the case of a patient successfully transplanted with V-A ECMO assistance using a percutaneous double lumen cannula as venous drainage (Protek Duo, CardiacAssist Inc., Pittsburgh, PA) and central aortic cannulation. The double lumen cannula allowed an optimal drainage of the venous system and effective emptying of right heart chambers.

Primary graft dysfunction following lung transplantation: From pathogenesis to future frontiers

Lung transplantation is the treatment of choice for patients with end-stage lung disease. Currently, just under 5000 lung transplants are performed worldwide annually. However, a major scourge leading to 90-d and 1-year mortality remains primary graft dysfunction. It is a spectrum of lung injury ranging from mild to severe depending on the level of hypoxaemia and lung injury post-transplant. This review aims to provide an in-depth analysis of the epidemiology, pathophysiology, risk factors, outcomes, and future frontiers involved in mitigating primary graft dysfunction. The current diagnostic criteria are examined alongside changes from the previous definition. We also highlight the issues surrounding chronic lung allograft dysfunction and identify the novel therapies available for ex-vivo lung perfusion. Although primary graft dysfunction remains a significant contributor to 90-d and 1-year mortality, ongoing research and development abreast with current technological advancements have shed some light on the issue in pursuit of future diagnostic and therapeutic tools.

Utilization of machine learning to model the effect of blood product transfusion on short-term lung transplant outcomes

The objective of this study was to identify the relationship between blood product transfusion and short-term morbidity and mortality following lung transplantation utilizing machine learning. Preoperative recipient characterstics, procedural variables, perioperative blood product transfusions, and donor charactersitics were included in the model. The primary composite outcome was occurrence on any of the following six endpoints: mortality during index hospitalization; primary graft dysfunction at 72 h post-transplant or the need for postoperative circulatory support; neurological complications (seizure, stroke, or major encephalopathy); perioperative acute coronary syndrome or cardiac arrest; and renal dysfunction requiring renal replacement therapy. The cohort included 369 patients, with the composite outcome occurring in 125 cases (33.9%). Elastic net regression analysis identified 11 significant predictors of composite morbidity: higher packed red blood cell, platelet, cryoprecipitate and plasma volume from the critical period, preoperative functional dependence, any preoperative blood transfusion, VV ECMO bridge to transplant, and antifibrinolytic therapy were associated with higher risk of morbidity. Preoperative steroids, taller height, and primary chest closure were protective against composite morbidity.

Intraoperative Support for Primary Bilateral Lung Transplantation: A Propensity-Matched Analysis

BACKGROUND

Single-center studies support benefits of venoarterial extracorporeal membrane oxygenation (VA-ECMO) as a method of intraoperative support. Propensity-matched data from a large cohort, however, are currently lacking. Therefore, our goal was to compare outcomes of intraoperative VA-ECMO and cardiopulmonary bypass (CPB) during bilateral lung transplantation (LTx) with a propensity analysis.

METHODS

We performed a retrospective analysis of 795 consecutive primary adult LTx patients (June 1, 2011-December 26, 2020) using no intraoperative support (n = 210), VA-ECMO (n = 150), or CPB (n = 197). Exclusion criteria included LTx on venovenous-ECMO, single/redo LTx, ex vivo lung perfusion, and concomitant solid-organ transplantation or cardiac procedure. Propensity analysis was performed comparing patients who underwent intraoperative CPB or VA-ECMO.

RESULTS

The propensity CPB group required more blood products at 72 hours (P = .02) and longer intensive care unit length of stay (P < .001) and ventilator dependence days (P < .001). There were no differences in cerebrovascular accident (P = 1), reintubation (P = .4), dialysis (P = .068), in-hospital mortality (P = .33), and 1-year (P = .67) and 3-year (P = .32) survival. The CPB group had a higher incidence of grade 3 primary graft dysfunction at 72 hours (P < .001). Neither support strategy was a predictor of 1- and 3-year mortality in our multivariable model (VA-ECMO, P = .72 and P = .57; CPB, P = .45 and P = .91, respectively).

CONCLUSIONS

Intraoperative VA-ECMO during lung transplantation was associated with fewer postoperative blood transfusions, shorter length of mechanical ventilation, and lower incidence of a grade 3 primary graft dysfunction at 72 hours. Although there were some differences in the postoperative course between the VA-ECMO and CPB groups, support type was not associated with differences in survival.

The American Association for Thoracic Surgery (AATS) 2022 Expert Consensus Document: The use of mechanical circulatory support in lung transplantation

OBJECTIVE

The use of mechanical circulatory support (MCS) in lung transplantation has been steadily increasing over the prior decade, with evolving strategies for incorporating support in the preoperative, intraoperative, and postoperative settings. There is significant practice variability in the use of these techniques, however, and relatively limited data to help establish institutional protocols. The objective of the AATS Clinical Practice Standards Committee (CPSC) expert panel was to review the existing literature and establish recommendations about the use of MCS before, during, and after lung transplantation.

METHODS

The AATS CPSC assembled an expert panel of 16 lung transplantation physicians who developed a consensus document of recommendations. The panel was broken into subgroups focused on preoperative, intraoperative, and postoperative support, and each subgroup performed a focused literature review. These subgroups formulated recommendation statements for each subtopic, which were evaluated by the entire group. The statements were then developed via discussion among the panel and refined until consensus was achieved on each statement.

RESULTS

The expert panel achieved consensus on 36 recommendations for how and when to use MCS in lung transplantation. These recommendations included the use of veno-venous extracorporeal membrane oxygenation (ECMO) as a bridging strategy in the preoperative setting, a preference for central veno-arterial ECMO over traditional cardiopulmonary bypass during the transplantation procedure, and the benefit of supporting selected patients with MCS postoperatively.

CONCLUSIONS

Achieving optimal results in lung transplantation requires the use of a wide range of strategies. MCS provides an important mechanism for helping these critically ill patients through the peritransplantation period. Despite the complex nature of the decision making process in the treatment of these patients, the expert panel was able to achieve consensus on 36 recommendations. These recommendations should provide guidance for professionals involved in the care of end-stage lung disease patients considered for transplantation.

New Aspects of Lung Transplantation: A Narrative Overview Covering Important Aspects of Perioperative Management

The management of lung transplant patients has continued to evolve in recent years. The year 2021 was marked by the publication of the International Consensus Recommendations for Anesthetic and Intensive Care Management of Lung Transplantation. There have been major changes in lung transplant programs over the last few years. This review will summarize the knowledge in anesthesia management of lung transplantation with the most recent data. It will highlight the following aspects which concern anesthesiologists more specifically: (1) impact of COVID-19, (2) future of transplantation for cystic fibrosis patients, (3) hemostasis management, (4) extracorporeal membrane oxygenation management, (5) early prediction of primary graft dysfunction, and (6) pain management.

Lung Transplantation in COVID-19 patients: What we have learned so far

Coronavirus-19 (COVID-19) can result in irrecoverable acute respiratory distress syndrome (ARDS) or life-limiting fibrosis for which lung transplantation is currently the only viable treatment. COVID-19 lung transplantation has transformed the field of lung transplantation, as before the pandemic, few transplants had been performed in the setting of infectious disease or ARDS. Given the complexities associated with COVID-19 lung transplantation, it requires strict patient selection with an experienced multidisciplinary team in a high-resource hospital setting. Current short-term outcomes of COVID-19 lung transplantation are promising. However, follow-up studies are needed to determine long-term outcomes and whether these patients may be predisposed to unique complications.

Textbook outcome in lung transplantation: Planned venoarterial extracorporeal membrane oxygenation versus off-pump support for patients without pulmonary hypertension

BACKGROUND

Planned venoarterial extracorporeal membrane oxygenation (VA ECMO) is increasingly used during bilateral orthotopic lung transplantation (BOLT) and may be superior to off-pump support for patients without pulmonary hypertension. In this single-institution study, we compared rates of textbook outcome between BOLTs performed with planned VA ECMO or off-pump support for recipients with no or mild pulmonary hypertension.

METHODS

Patients with no or mild pulmonary hypertension who underwent isolated BOLT between 1/2017 and 2/2021 with planned off-pump or VA ECMO support were included. Textbook outcome was defined as freedom from intraoperative complication, 30-day reintervention, 30-day readmission, post-transplant length of stay >30 days, 90-day mortality, 30-day acute rejection, grade 3 primary graft dysfunction at 48 or 72 hours, post-transplant ECMO, tracheostomy within 7 days, inpatient dialysis, reintubation, and extubation >48 hours post-transplant. Textbook outcome achievement was compared between groups using multivariable logistic regression.

RESULTS

Two hundred thirty-seven BOLTs were included: 68 planned VA ECMO and 169 planned off-pump. 14 (20.6%) planned VA ECMO and 27 (16.0%) planned off-pump patients achieved textbook outcome. After adjustment for prior BOLT, lung allocation score, ischemic time, and intraoperative transfusions, planned VA ECMO was associated with higher odds of textbook outcome than planned off-pump support (odds ratio 3.89, 95% confidence interval 1.58-9.90, p = 0.004).

CONCLUSIONS

At our institution, planned VA ECMO for isolated BOLT was associated with higher odds of textbook outcome than planned off-pump support among patients without pulmonary hypertension. Further investigation in a multi-institutional cohort is warranted to better elucidate the utility of this strategy.

Lung transplantation in patients with a history of anatomical native lung resection

OBJECTIVES

History of anatomical lung resection complicates lung transplantation (LTx). Our aim was to identify indications, intraoperative approach, and outcome in these challenging cases in a retrospective multicentre cohort analysis.

METHODS

Members of the ESTS Lung Transplantation Working Group were invited to submit data on patients undergoing LTx after a previous anatomical native lung resection between 01/2005 and 07/2020. The primary end-point was overall survival (Kaplan-Meier estimation).

RESULTS

Out of 2690 patients at 7 European centers, 26 (1%) patients (14 male; median age 33 years) underwent LTx after a previous anatomical lung resection. Median time from previous lung resection to LTx was 12 years. The most common indications for lung resection were infections (n = 17), emphysema (n = 5), lung tumour (n = 2), and others (n = 2). Bronchiectasis (cystic fibrosis (CF) or non-CF related) was the main indication for LTx (n = 21), followed by COPD (n = 5). Two patients with a previous pneumonectomy underwent contralateral single LTx and 1 patient with a previous lobectomy had ipsilateral single LTx. The remaining 23 patients underwent bilateral LTx. Clamshell incision was performed in 12 (46%) patients. Moreover, LTx was possible without extracorporeal life support in 13 (50%) patients. 90-day mortality was 8% (n = 2) and the median survival was 8.7 years.

CONCLUSIONS

History of anatomical lung resection is rare in LTx candidates. The majority of patients are young and diagnosed with bronchiectasis. Although the numbers were limited, survival after LTx in patients with previous anatomical lung resection, including pneumonectomy is comparable to reported conventional LTx for bronchiectasis.

Regression of Tricuspid Valve Regurgitation After Lung Transplant: A Single-Center Experience

BACKGROUND

Although tricuspid regurgitation (TR) is common in candidates for lung transplant, no data or established guidelines exist regarding the need for surgical repair at the time of transplant. We aimed to evaluate the natural course of TR by assessing the incidence and extent of TR regression among patients who did not undergo tricuspid valve repair (TVR) concomitantly with lung transplant.

METHODS

We retrospectively identified adult patients who underwent lung transplant without TVR at our institution from 2001 through 2017. Pretransplant and posttransplant echocardiograms were reviewed to assess severity of TR, tricuspid annular plane systolic excursion, central venous pressure, mean pulmonary arterial pressure, and right ventricular size and function.

RESULTS

Among 553 included patients, 324 (58.7%) were men, the mean (SD) age was 61.9 years (12.7), and 417 (75.4%) had a double lung transplant. TR before transplant was reported as trivial in 265 patients (47.9%), mild in 235 (42.5%), moderate in 40 (7.2%), and severe in 13 (2.4%). After transplant, TR improved significantly overall (P < .001). TR improved in 193 patients: 158 patients (81.9%) by 1 grade and 35 patients (18.1%) by 2 or more grades. Additionally, of 53 patients with pretransplant moderate or severe TR, 44 (83%) had improvement to mild, trivial, or no TR. After transplant, 12 patients (2.2%) had no remaining TR.

CONCLUSION

The severity of TR improved or showed no change in most patients after lung transplant, which obviates the need for TVR among most lung transplant recipients.

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.

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.

Intraoperative use of extracorporeal CO2 removal (ECCO2R) and emergency ECMO requirement in patients undergoing lung transplant: a case-matched cohort retrospective study

BACKGROUND

The use of extracorporeal carbon dioxide removal (ECCO₂R) is less invasive than extracorporeal membrane oxygenation (ECMO), and intraoperative control of gas exchange could be feasible. The aim of this study in intermediate intraoperative severity patients undergoing LT was to assess the role of intraoperative ECCO₂R on emergency ECMO requirement in patients.

METHODS

Thirty-eight consecutive patients undergoing lung transplantation (LT) with "intermediate" intraoperative severity in the intervals 2007 to 2010 or 2011 to 2014 were analyzed as historical comparison of case-matched cohort retrospective study. The "intermediate" intraoperative severity was defined as the development of intraoperative severe respiratory acidosis with maintained oxygenation function (i.e., pH <7.25, PaCO₂ >60 mmHg, and PaO₂/FiO₂ >150), not associated with hemodynamic instability. Of these 38 patients, twenty-three patients were treated in the 2007-2010 interval by receiving "standard intraoperative treatment," while 15 patients were treated in the 2011-2014 interval by receiving "standard intraoperative treatment + ECCO₂R."

RESULTS

ECMO requirement was more frequent among patients that received "standard intraoperative treatment" alone than in those treated with "standard intraoperative treatment + ECCO₂R" (17/23 vs. 3/15; p = 0.004). The use of ECCO₂R improved pH and PaCO₂ while mean pulmonary artery pressure (mPAP) decreased.

CONCLUSION

In intermediate intraoperative severity patients, the use of ECCO₂R reduces the ECMO requirement.

Anesthetic Management During Lung Transplantation - What's New in 2021?

As outcomes of lung transplantation (LTx) are improving transplant centers are pushing boundaries. There has been a steady increase in the medical complexity of lung transplant candidates. Many transplant centers are listing older patients with comorbidities, and there has been a steady rise in the number of candidates supported with extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation. There has been a growing appreciation of the importance intraoperative management of potentially modifiable risk factors has on postoperative outcomes. Evidence suggests that LTx even in high-risk patients requiring perioperative ECMO can offer excellent results. This article outlines the current state-of-the-art intraoperative management of LTx.

Early Postoperative Management of Lung Transplant Recipients

The early postoperative period after lung transplantation is a critical time. Prompt recognition and treatment of primary graft dysfunction can alter long-term allograft function. Cardiovascular, gastrointestinal, renal, and hematologic derangements are common and require close management to limit their negative sequelae.

Clinical Characteristics and Outcomes of Patients With COVID-19-Associated Acute Respiratory Distress Syndrome Who Underwent Lung Transplant

Importance

Lung transplantation is a potentially lifesaving treatment for patients who are critically ill due to COVID-19-associated acute respiratory distress syndrome (ARDS), but there is limited information about the long-term outcome.

Objective

To report the clinical characteristics and outcomes of patients who had COVID-19-associated ARDS and underwent a lung transplant at a single US hospital.

Design, Setting, and Participants

Retrospective case series of 102 consecutive patients who underwent a lung transplant at Northwestern University Medical Center in Chicago, Illinois, between January 21, 2020, and September 30, 2021, including 30 patients who had COVID-19-associated ARDS. The date of final follow-up was November 15, 2021.

Exposures

Lung transplant.

Main Outcomes and Measures

Demographic, clinical, laboratory, and treatment data were collected and analyzed. Outcomes of lung transplant, including postoperative complications, intensive care unit and hospital length of stay, and survival, were recorded.

Results

Among the 102 lung transplant recipients, 30 patients (median age, 53 years [range, 27 to 62]; 13 women [43%]) had COVID-19-associated ARDS and 72 patients (median age, 62 years [range, 22 to 74]; 32 women [44%]) had chronic end-stage lung disease without COVID-19. For lung transplant recipients with COVID-19 compared with those without COVID-19, the median lung allocation scores were 85.8 vs 46.7, the median time on the lung transplant waitlist was 11.5 vs 15 days, and preoperative venovenous extracorporeal membrane oxygenation (ECMO) was used in 56.7% vs 1.4%, respectively. During transplant, patients who had COVID-19-associated ARDS received transfusion of a median of 6.5 units of packed red blood cells vs 0 in those without COVID-19, 96.7% vs 62.5% underwent intraoperative venoarterial ECMO, and the median operative time was 8.5 vs 7.4 hours, respectively. Postoperatively, the rates of primary graft dysfunction (grades 1 to 3) within 72 hours were 70% in the COVID-19 cohort vs 20.8% in those without COVID-19, the median time receiving invasive mechanical ventilation was 6.5 vs 2.0 days, the median duration of intensive care unit stay was 18 vs 9 days, the median post-lung transplant hospitalization duration was 28.5 vs 16 days, and 13.3% vs 5.5% required permanent hemodialysis, respectively. None of the lung transplant recipients who had COVID-19-associated ARDS demonstrated antibody-mediated rejection compared with 12.5% in those without COVID-19. At follow-up, all 30 lung transplant recipients who had COVID-19-associated ARDS were alive (median follow-up, 351 days [IQR, 176-555] after transplant) vs 60 patients (83%) who were alive in the non-COVID-19 cohort (median follow-up, 488 days [IQR, 368-570] after lung transplant).

Conclusions and Relevance

In this single-center case series of 102 consecutive patients who underwent a lung transplant between January 21, 2020, and September 30, 2021, survival was 100% in the 30 patients who had COVID-19-associated ARDS as of November 15, 2021.

Intraoperative support during lung transplantation

The role of intraoperative mechanical support during lung transplantation (LTx) is essential to provide a safe hemodynamic and ventilatory status during critical intraoperative events. This hemodynamic and ventilatory stability is vital to minimize the odds of suboptimal outcomes, especially considering that, due to the scarcity of donors and the fact that more and more patients with significant comorbidities are being considered for this therapy, a more aggressive approach is often needed by the transplant centers. Hence, the attenuation of any potential injury that can happen during this complex event is paramount. While a thorough assessment of the donor and optimization of postoperative care is pursued, certainly protective intraoperative management would also contribute to better outcomes. Understanding each patient’s underlying anatomy and cardiopulmonary physiology, associated with awareness of critical events during a complicated procedure like LTx, is essential for a precise indication and safe use of support. Cardiopulmonary bypass (CPB) and veno-arterial extracorporeal membrane oxygenation (VA ECMO) have been the most common approaches used, with the latter gaining popularity more recently and we have used VA ECMO exclusively for the last decade. New technologies certainly contributed to more liberal use of VA ECMO intraoperatively, enabling a protecting and physiologic environment for the newly implanted grafts. In this setting, potential prophylactic use for lung protection during a critical period is also considered.

Central, peripheral ECMO or CPB? Comparsion between circulatory support methods used during lung transplantation

BACKGROUND

Chronic obstructive pulmonary disease, cystic fibrosis and usual interstitial pneumonia are three most common indications for lung transplantation (LuTx) in Poland. As a result of irreversible destruction of pulmonary parenchyma and extended respiratory insufficiency that appear afterwards, it is crucial to estimate the reserve of gas exchange in each lung before and during surgery. Altering conditions of gas exchange require adaptation in circulatory system as well. In some of the cases the use of extracorporeal life support appears to be necessary to undergo the transplantation successfully. Cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) used during operation allow to replace the function of heart and lung, but they are also related to complications in the form of acute kidney failure, bleeding, heart arrhythmias or thromboembolic complications.

METHODS

We reviewed 77 LuTx from 2009 to 2020 performed at the Department of Thoracic Surgery and Transplantation. 40/77 (51%) patients required intraoperative extracorporeal assistance: 8 required CBP and 32 required ECMO. In the ECMO group 14/32 (44%) patients had peripheral cannulation and 18/32 (56%) had central one. We have calculated the survival rates and reviewed postoperative complications after lung transplantations. Cumulative Kaplan-Meier survival curves were calculated. Differences between the groups were evaluated by the Chi- square analysis for discontinuous variables and t-test for continuous variables.

RESULTS

The use of intraoperative central extracorporeal membrane oxygenator was associated with increased survival rates comparing to patients without external support (30-days, 1-year, 3-years, 5-years rates: 78%, 66%, 66%, 66% vs 83%, 65%, 59%, 44% respectively). Furthermore, survival was enhanced comparing to peripheral ECMO or cardiopulmonary bypass as well (50%, 41%, 41%, 33%; 75%, 50%, 50%, 38% respectively). Acute kidney injury and thromboembolic complications occurred statistically more often in case of patients that underwent lung transplantation with support devices (p = 0.005, p = 0.02 respectively). Frequency of other complications was comparable among groups.

CONCLUSIONS

The use of central extracorporeal membrane oxygenation should be favorized over peripheral cannulation or cardiopulmonary bypass. CPB should be no longer used during LuTx. Trial registration Not applicable.

Blood Lactate During Double-Lung Transplantation: A Predictor of Grade-3 Primary Graft Dysfunction

OBJECTIVE

Many prognostic factors of grade-3 primary graft dysfunction at postoperative day 3 (PGD3-T72) have been reported, but intraoperative blood lactate level has not been studied. The present retrospective study was done to test the hypothesis that intraoperative blood lactate level (BLL) could be a predictor of PGD3-T72 after double-lung transplantation.

DESIGN

Retrospective monocentric cohort study.

SETTING

Foch University Hospital, Suresnes, France.

PARTICIPANTS

Patients having received a double-lung transplantation between 2012 and 2019. Patients transplanted twice during the study period, having undergone a multiorgan transplantation, or cardiopulmonary bypass, and those under preoperative extracorporeal membrane oxygenation, were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Analysis was performed on a cohort of 449 patients. Seventy-two (16%) patients had a PGD3-T72. Blood lactate level increased throughout surgery to reach a median value of 2.2 (1.6-3.2) mmol/L in the No-PGD3-T72 group and 3.4 (2.3-5.0) mmol/L in the PGD3-T72 group after second lung implantation. The best predictive model for PGD3-T72 was obtained adding a lactate threshold of 2.6 mmol/L at the end of surgery to the clinical model, and the area under the curve was 0.867, with a sensitivity = 76.9% and specificity = 85.4%. Repeated-measures mixed model of BLL during surgery remained significant after adjustment for covariates (F ratio= 4.22, p < 0.001 for interaction).

CONCLUSIONS

Blood lactate level increases during surgery and reaches a maximum after the second lung implantation. A value below the threshold of 2.6 mmol/L at the end of surgery has a high negative predictive value for the occurrence of a grade-3 primary graft dysfunction at postoperative day 3.

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.

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part II: Cardiac, surgical, perioperative, operative, and post-operative challenges and management statements

Patients with connective tissue disease (CTD) present unique surgical, perioperative, operative, and postoperative challenges related to the often underlying severe pulmonary hypertension and right ventricular dysfunction. The International Society for Heart and Lung Transplantation-supported consensus document on lung transplantation in patients with CTD standardization addresses the surgical challenges and relevant cardiac involvement in the perioperative, operative, and postoperative management in patients with CTD.

Lung transplantation for acute exacerbation of interstitial lung disease

BACKGROUND

Acute exacerbations of interstitial lung diseases (AE-ILD) have a high mortality rate with no effective medical therapies. Lung transplantation is a potentially life-saving option for patients with AE-ILD, but its role is not well established. The aim of this study is to determine if this therapy during AE-ILD significantly affects post-transplant outcomes in comparison to those transplanted with stable disease.

METHODS

We conducted a retrospective study of consecutive patients with AE-ILD admitted to our institution from 2015 to 2018. The comparison group included patients with stable ILD listed for lung transplant during the same period. The primary end-points were in-hospital mortality for patients admitted with AE-ILD and 1-year survival for the transplanted patients.

RESULTS

Of 53 patients admitted for AE-ILD, 28 were treated with medical therapy alone and 25 underwent transplantation. All patients with AE-ILD who underwent transplantation survived to hospital discharge, whereas only 43% of the AE-ILD medically treated did. During the same period, 67 patients with stable ILD underwent transplantation. Survival at 1 year for the transplanted patients was not different for the AE-ILD group versus stable ILD group (96% vs 92.5%). The rates of primary graft dysfunction, post-transplant hospital length-of-stay and acute cellular rejection were similar between the groups.

CONCLUSION

Patients with ILD transplanted during AE-ILD had no meaningful difference in overall survival, rate of primary graft dysfunction or acute rejection compared with those transplanted with stable disease. Our results suggest that lung transplantation can be considered as a therapeutic option for selected patients with AE-ILD.

Blood product transfusion and lung transplant outcomes: A systematic review

The perioperative transfusion of blood products has long been linked to development of acute lung injury and associated with mortality across both medical and surgical patient populations.^1,2 The need for blood product transfusion during and after lung transplantation is common and, in many instances, unavoidable. However, this practice may potentially be modifiable.³ In this systematic review, we explore and summarize what is known regarding the impact of blood product transfusion on outcomes following lung transplantation, highlighting the most recent work in this area. Overall, the majority of the literature consists of single center retrospective analyses or the work of multicenter working groups referencing the same database. In the end, there are a number of remaining questions regarding blood product transfusion and their downstream effects on graft function and survival.

Preclosing of the femoral artery allows total percutaneous venoarterial extracorporeal membrane oxygenation and prevents groin wound infection after lung transplantation

OBJECTIVES

In lung transplantation (LT), femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO) usually requires an open approach that may be associated with severe groin wound infection. In endovascular aortic procedures, preclosing of the femoral artery (PFA) with vascular closure devices allows the percutaneous insertion and withdrawal of large-bore cannulae. We sought to evaluate whether this innovative technique could be applied in the specific setting of LT to achieve total percutaneous VA-ECMO and decrease groin wound infection.

METHODS

We conducted a retrospective study of a prospective database including patients who underwent LT in our centre from January 2011 to December 2017. Patients who underwent peripheral VA-ECMO using the PFA technique after January 2014 (PFA group, n = 106) were compared to those who underwent peripheral VA-ECMO using open cannulation and/or decannulation before January 2014 (non-PFA group, n = 48). The primary end point was the rate of technical success defined as total percutaneous VA-ECMO. Secondary end points included groin wound infections and delayed vascular complications.

RESULTS

The PFA technique was technically successful in 98 patients (92.5%). As compared with the non-PFA group, the PFA group was characterized by a similar rate of vascular complications (16.6% vs 11.3%, P = 0.360) and a decreased rate of groin wound infection (18.9% vs 0%, P < 0.001). In multivariate analysis, risk factors associated with vascular complications following PFA included female sex, peripheral arterial disease and ECMO duration.

CONCLUSIONS

In LT patients, PFA is associated with a high rate of total percutaneous VA-ECMO, thus preventing the occurrence of groin wound infection.

Extracorporeal life support during lung transplantation

Lung transplantation surgeries are performed without extracorporeal life support (ECLS) by using an off-pump technique; however, in cases of hypoxemia or hemodynamic instability, intraoperative ECLS may be required. Cardiopulmonary bypass (CPB) has traditionally been the standard practice for ECLS but has been associated with an increased risk of bleeding in the perioperative period, increased transfusion requirements, prolonged postoperative intubation, and possibly primary graft dysfunction. More recently, because of the flexibility of using extracorporeal membrane oxygenation (ECMO) in bridging to transplantation and during postoperative recovery, its use has increased. CPB and ECMO each has advantages and disadvantages; however, because comparisons of CPB and ECMO have been limited to small retrospective observational and single-institution studies, more research is required to determine the superiority of one modality. In this review, we critically examine the pros and cons of performing lung transplantation surgery off-pump or by using the ECLS modalities of ECMO and CPB support during lung transplantation surgery.

Anesthetic management in lung transplantation: Our single-center experience

Background

In this study, we aimed to discuss our anesthesia management strategies, experiences, and outcomes in patients undergoing lung transplantation.

Methods

Between December 2016 and December 2018, a total of 53 patients (43 males, 10 females; mean age: 46.1±13 years; range, 14 to 64 years) undergoing lung transplantation in our center were included. The anesthesia technique, patients" characteristics, and perioperative clinical and follow-up data were recorded. The stage of lung disease was assessed using the New York Heart Association functional classification.

Results

Two patients underwent single lung transplantation, while 51 patients underwent double lung transplantation. Idiopathic pulmonary fibrosis was the most common indication in 41.5% of the patients. All patients had end-stage lung disease (Class IV) and 79% were oxygen-dependent. The extracorporeal membrane oxygenation support was given to 32 patients.

Conclusion

The anesthetic management of lung transplantation is challenging, either due to the deterioration of the recipient"s physical performance and the complexity of the surgical techniques used. In general, a kind of mechanical support may be needed and extracorporeal membrane oxygenation is the first choice in the majority of patients. A close communication should be maintained between the surgeons, perfusion technicians, and anesthesiologists to ensure an optimal multidisciplinary approach and to achieve successful outcomes.

Perioperative circulatory support for lung transplantation

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) has recently replaced cardiopulmonary bypass (CPB) as the preferred option for providing circulatory support during lung transplantation. This review aimed to summarize the previous data and to address the relative use of ECMO and CPB during lung transplantation.

METHODS

The database was searched in PubMed (Medline) using the following keywords: lung transplantation, extracorporeal membrane oxygenation, and cardiopulmonary bypass, for all relevant reports which were written in English and were published between 2000 and 2020.

REVIEW

Several reports have revealed that intraoperative use of ECMO is associated with lower blood product transfusion requirements, shorter ventilator support, and shorter length of hospital stay. During recent years, preoperative ECMO has also been used with favorable outcomes as a bridge to lung transplantation in critically ill patients.

CONCLUSIONS

The use of ECMO during lung transplantation seems to reduce postoperative complications and improve short-term outcomes, relative to CPB. However, additional data should be collected through large multicenter randomized controlled trials. Furthermore, preoperative ECMO as a bridge to lung transplantation appears to provide favorable outcomes, although additional data are also needed from experienced transplant centers.

A comparison of cardiopulmonary bypass versus extracorporeal membrane oxygenation: Does intraoperative circulatory support strategy affect outcomes in pediatric lung transplantation?

OBJECTIVE

Data on adult lung transplantation suggest perioperative benefits of intraoperative extracorporeal membrane oxygenation (ECMO) compared to cardiopulmonary bypass (CPB). Information regarding their pediatric counterparts, however, is limited. This study compares outcomes of intraoperative ECMO versus CPB in pediatric lung transplantation.

METHODS

We reviewed all pediatric lung transplants at our institution from 2014 to 2019 and compared those supported intraoperatively on ECMO (n = 13) versus CPB (n = 22), plus a conditional analysis excluding re-transplantations (ECMO [n = 13] versus CPB [n = 20]). We evaluated survival, surgical times, intraoperative transfusions, postoperative support, complications, and duration of hospitalization.

RESULTS

Total time on ECMO support was significantly less than that of CPB support (P = .018). Intraoperatively, the ECMO group required fewer transfusions of fresh-frozen plasma (8.9 [5.8-22.3] vs 16.6 [11.4-39.0] mL/kg, P = .049) and platelets (4.2 [0.0-6.7] vs 8.0 [3.5-14.0] mL/kg, P = .049). When excluding re-transplantations, patients on ECMO required fewer packed red blood cells intraoperatively (12.6 [2.1-30.7] vs 28.2 [14.0-54.0] mL/kg, P = .048). There were no differences in postoperative support requirements, complications, or mortality at one, six, and twelve months.

CONCLUSIONS

Intraoperative ECMO support during pediatric lung transplantation appears to decrease intraoperative transfusion requirements when compared to CPB. Data from additional institutions may strengthen these observations.

Procedural mechanical support for lung transplantation

PURPOSE OF REVIEW

The use of procedural mechanical support during lung transplantation (LTx) varies between centers and the optimal support strategy is still controversially discussed. The two main questions are if cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) should be preferred and whether mechanical support should be reserved for specific patient groups or a routine use can be recommended.

RECENT FINDINGS

Recent cohort studies have consistently shown that LTx on CPB leads to inferior outcomes when compared to venoarterial (va)-ECMO. Thus, ECMO should be preferred in lung transplantation except for special indications. Despite its higher invasiveness, ECMO offers some pivotal advantages over off-pump lung transplantation. It has been shown to remarkably reduce rates of primary graft dysfunction, supporting the concept of a routine intraoperative ECMO use in LTx.

SUMMARY

Although randomized-controlled trials addressing this question are still lacking, current evidence appears to favor the routine use of ECMO support during lung transplantation.

Evolution of Recipient Characteristics Over 3 Decades and Impact on Survival After Lung Transplantation

BACKGROUND

Lung transplantation (LTx) is a definitive treatment for end-stage lung disease. Herein, we reviewed our center experience over three decades to examine the evolution of recipient characteristics and contemporary predictors of survival for LTx.

METHODS

We retrospectively reviewed the data of LTx procedures performed at our institution from 1/1990 to 1/2019 (n=1819). The cohort is divided into three eras; I: 1990-1998 (n=152), II: 1999-2008 (n=521), III: 2009-2018 (n=1146). Uni- and multivariate analyses of survival in era III were performed.

RESULTS

Pulmonary fibrosis has become the leading indication for LTx (13% in Era I, 57% in Era III). Median recipient age increased (Era I: 46 years - Era III: 61 years) as well as intraoperative mechanical circulatory support (Era I: 0% - Era III: 6%). Higher lung allocation score (LAS) was associated with primary graft dysfunction (PGD) (p<0.0001), postoperative ECMO (p<0.0001), and in-hospital mortality (p=0.002). In Era III, hypoalbuminemia, thrombocytopenia, and high PGD grade were multivariate predictors of early mortality. The 5-year survival in Era II (55%) and III (55%) were superior to Era I (40%, p<0.001). Risk factors for late mortality in era III included recipient age, chronic allograft dysfunction, renal dysfunction, high MELD score, and single LTx.

CONCLUSIONS

In this longitudinal single-center study, recipient characteristics have evolved to include sicker patients with greater complexity of procedures and risk for postoperative complications but without significant impact on hospital mortality or long-term survival. With advancing surgical techniques and perioperative management, there is room for further progress in the field.Supplemental Visual Abstract; http://links.lww.com/TP/C191.

The Effect of Additional Stepwise Venous Inflow on Differential Hypoxia of Veno-Arterial Extracorporeal Membrane Oxygenation

Use of femoral-femoral veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) for cardiopulmonary support during lung transplantation can be inadequate for efficient distribution of oxygenated blood into the coronary circulation. We hypothesized that creating a left-to-right shunt flow using veno-arterio-venous (VAV) ECMO would alleviate the differential hypoxia. Total 10 patients undergoing lung transplantation were enrolled in this study. An additional inflow cannula was inserted into the right internal jugular (RIJ) vein for VAV ECMO. During left one-lung ventilation using a 1.0 inspired oxygen fraction (FiO₂), the left-to-right shunt flow was incrementally increased from 0 to 500, 1,000, and 1,500 ml/min. The arterial oxygen partial pressure (PaO₂) and oxygen saturation (SaO₂) were measured at the proximal ascending aorta and right radial artery. The ascending aorta gas analysis revealed that six patients had a PaO₂/FiO₂ ratio less than 200 mm Hg at a 0 ml/min shunt flow. The PaO₂ (SaO₂) values were 48.5 ± 14.8 mm Hg (80.9 ± 11.6%) at the ascending aorta and 77.8 ± 69.7 mm Hg (83.3 ± 13.2%) at the right radial artery. As the left-to-right shunt flow rate increased over 1,000 ml/min, the PaO₂ and SaO₂ values for the ascending aorta and right radial artery significantly increased. In conclusion, femoral-femoral VA ECMO can produce suboptimal coronary oxygenation in patients unable to tolerate one-lung ventilation. A left-to-right shunt using VAV ECMO can alleviate the differential hypoxia.