Extracorporeal Support During Bilateral Sequential Lung Transplantation in Patients With Pulmonary Hypertension: Risk Factors and Outcomes

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.

Anesthetic considerations in lung transplantation: past, present and future

Lung transplantation is a very complex surgical procedure with many implications for the anesthetic care of these patients. Comprehensive preoperative evaluation is an important component of the transplant evaluation as it informs many of the decisions made perioperatively to manage these complex patients effectively and appropriately. These decisions may involve pre-emptive actions like pre-habilitation and nutrition optimization of these patients before they arrive for their transplant procedure. Appropriate airway and ventilation management of these patients needs to be performed in a manner that provides an optimal operating conditions and protection from ventilatory injury of these fragile post-transplant lungs. Pain management can be challenging and should be managed in a multi-modal fashion with or without the use of an epidural catheter while recognizing the risk of neuraxial technique in patients who will possibly be systemically anticoagulated. Complex monitoring is required for these patients involving both invasive and non-invasive including the use of transesophageal echocardiography (TEE) and continuous cardiac output monitoring. Management of the patient's hemodynamics can be challenging and involves managing the systemic and pulmonary vascular systems. Some patients may require extra-corporeal lung support as a planned part of the procedure or as a rescue technique and centers need to be proficient in instituting and managing this sophisticated method of hemodynamic support.

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.

Comparison of mechanical cardiopulmonary support strategies during lung transplantation

INTRODUCTION

Lung transplantation outcomes are influenced by the intraoperative mechanical cardiopulmonary support strategy used. This surgery was historically done either on cardiopulmonary bypass (CPB) or off pump. Recently, there has been increased interest in intraoperative support with veno-arterial (VA) or veno-venous (VV) extracorporeal membrane oxygenation (ECMO). However, there is a lack of consensus on the relative risks, benefits and indications for each intraoperative support strategy.

AREAS COVERED

This review includes information from cohort studies, case-control studies, and case series that compare morbidity and/or mortality of two or more intraoperative cardiopulmonary support strategies during lung transplantation.

EXPERT OPINION

The optimal strategy for intraoperative cardiopulmonary support during lung transplantation remains an area of debate. Current data suggest that off pump is associated with better outcomes and could be considered whenever feasible. ECMO is generally associated with preferable outcomes to CPB, but the data supporting this association is not robust. Interestingly, whether CPB is unplanned or prolonged might influence outcomes more than the use of CPB itself. These observations can help guide surgical teams in their approach for intraoperative mechanical support strategy during lung transplantation and should serve as the basis for further investigations.

Intraoperative extracorporeal membrane oxygenation for lung transplantation in cystic fibrosis patients: Predictors and impact on outcome

BACKGROUND

Predictors and outcomes of intraoperative extracorporeal membrane oxygenation (ECMO) during lung transplantation (LUTX) for cystic fibrosis (CF) are unknown.

METHODS

We retrospectively collected the clinical data at enlistment of the CF patients who underwent double LUTX from January 2013 to December 2018 at an Italian tertiary referral center. We compared blood transfusions, incidence of primary graft dysfunction (PGD), duration of mechanical ventilation, intensive care unit (ICU) length of stay (LOS), hospital LOS and survival of ECMO and non-ECMO patients. Chi-square, Kruskal-Wallis, and log-rank tests were used.

RESULTS

Twenty-eight (40%) of the 70 included patients needed intraoperative central veno-arterial ECMO with postoperative veno-venous prolongation in 6 subjects. Lower right ventricle ejection fraction (p = 0.013, OR 0.92(0.86-0.98)), higher oxygen requirement (p = 0.026, OR 1.39(1.01-1.90)), lower body surface area (p = 0.044, OR 0.05(0.00-1.03)), and CF-related diabetes (p = 0.044, OR 2.81(1.03-7.66)) were associated with intraoperative ECMO. Compared to non-ECMO patients, ECMO patients needed almost fivefold intraoperative transfusion (2227 mL vs. 570 mL, p<0.001) and had PGD grade > 0 at 72 h more frequently (16/57% vs. 12/28%, p = 0.017, OR 3.33(1.22-9.09)). Mechanical ventilation, ICU LOS and hospital LOS were significantly longer in ECMO patients. Survival at follow-up (651(326-1277) days) of ECMO and non-ECMO patients was 78% vs. 83%, respectively (OR 0.73 (0.21-2.46), p = 0.616, log-rank test p = 0.498).

CONCLUSION

Pre-operative risk assessment and clinical planning should be done according to the predictors above. While undeniably useful as a life-saving procedure, ECMO during LUTX for CF is associated with worsened short-term outcomes. ECMO should be implemented weighing its risk and benefits.

Pre-anaesthetic evaluation of the patient with end-stage lung disease

Lung transplantation is a viable alternative for end-stage lung diseases, which offers good quality of life and survival outcomes for recipients. The aims of pre-assessment for potential lung transplant recipients are to assess fitness for surgery, optimise co-morbidities, commence interventions or investigations, weigh risk-benefit ratio, plan appropriate analgesia and obtain informed consent. The assessment information is gathered from the medical record, patient interview, physical examination and pre-operative tests. A comprehensive workup includes cardiopulmonary evaluation, haematological, biochemical, microbiological and immunological investigations. Most of the evidence regarding lung transplantation is gleaned from retrospective data from single, multi-centre or multinational registries. The lack of good quality evidence means that the guidelines are based on expert consensus.

Noteworthy Literature Published in 2016 for Thoracic Organ Transplantation Anesthesiologists

This article is first in the series to review the published literature on perioperative issues in patients undergoing thoracic solid organ transplantations. We present recent literature from 2016 on preoperative considerations, organ preservation, intraoperative anesthesia management, surgical techniques, postoperative complications, and the impact of perioperative management on short- and long-term outcomes that are pertinent to thoracic transplantation anesthesiologists.