Bridging to lung transplantation with extracorporeal circulatory support: when or when not?

[Peripheral extracorporeal membrane oxygenation in perioperative medicine : Principles, indications and challenges]

In recent years the number of patients treated in intensive care units by extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure or cardiogenic shock has steadily increased [1]. Consequently, the number of invasive procedures and operations in these patients has also increased. A fundamental understanding of these systems and the clinical indications is therefore helpful for the practicing (non-cardiac) surgeon. This review article focuses on peripheral ECMO procedures: venovenous (V-V) ECMO for patients with respiratory failure and venoarterial (V-A) ECMO for circulatory support in cardiogenic shock.

Impact of Extracorporeal Membrane Oxygenation Bridging Duration on Lung Transplant Outcomes

BACKGROUND

We sought to characterize the association between venovenous extracorporeal membrane oxygenation (VV-ECMO) bridging duration and outcomes in patients listed for lung transplantation.

METHODS

A retrospective observational study was conducted using the Organ Procurement and Transplantation Network (OPTN) database to identify adults (aged ≥18 years) who were listed for lung transplantation between 2016 and 2020 and were bridged with VV-ECMO. Patients were then stratified into groups, determined by risk inflection points, depending on the amount of time spent on pretransplant ECMO: group 1 (≤5 days), group 2 (6-10 days), group 3 (11-20 days), and group 4 (>20 days). Waiting list survival between groups was analyzed using Fine-Gray competing risk models. Posttransplant survival was compared using Cox regression.

RESULTS

Of 566 eligible VV-ECMO bridge-to-lung-transplant patients (median age, 54 years, 49% men), 174 (31%), 124 (22%), 130 (23%), and 138 (24%) were categorized as groups 1, 2, 3, and 4, respectively. Overall, median duration of VV-ECMO was 10 days (interquartile range, 1-211 days), and 178 patients (31%) died on the waiting list. In the Fine-Gray model, compared with group 1, patients bridged with longer ECMO durations in group 2 (subdistribution hazard ratio [SHR], 2.95; 95% CI, 1.63-5.35), group 3 (SHR, 3.96; 95% CI, 2.36-6.63), and group 4 (SHR, 4.33; 95% CI, 2.59-7.22, all P < .001) were more likely to die on the waiting list. Of 388 patients receiving a transplant, pretransplant ECMO duration was not associated with 1-year survival in Cox regression.

CONCLUSIONS

Prolonged duration of ECMO bridging was associated with worse waiting list mortality but did not impact survival after lung transplant. Prioritization of very early transplantation may improve waiting list outcomes in this population.

Hemocompatibility Evaluation of a Novel Ambulatory Pulmonary Assist System Using a Lightweight Axial-Flow Pump

The Pulmonary Assist System (PAS) is currently under development as a wearable respiratory assist system. In this study, the hemocompatibility of the PAS's axial-flow mechanical pump (AFP) was compared to other contemporary mechanical pumps in an acute ovine model. The PAS was attached to a normal sheep in a venovenous configuration using one of three pumps: 1) AFP, 2) ReliantHeart HeartAssist 5 (control), or 3) Abbott Pedimag (control) (n = 5 each). Each sheep was supported on the PAS for 12 hours with two L/minute of blood flow and four L/minute of sweep gas. Hemolysis, coagulation, inflammation, and platelet activation and loss were compared among the groups. In this study, the plasma-free hemoglobin (pfHb) was less than 10 mg/dl in all groups. The pfHb was significantly lower in the AFP group compared to other groups. There was no significant clot formation in the pumps and oxygenators in all groups. Furthermore, no significant differences in coagulation (oxygenator resistance, fibrinopeptide A), inflammation (white blood cell counts, IL-8), and platelet activation and loss (p-selectin, platelet counts) were observed among the groups (all, p > 0.05). This study demonstrates equivalent hemocompatibility of the PAS's AFP to other contemporary mechanical pumps with a reduced level of hemolysis on startup.

Update in lung transplantation: anesthetic considerations

The field of lung transplantation (LTx) has expanded rapidly since its inception in the early 1960s with the work of James Hardy and colleagues at the University of Mississippi from the work of local single specialty physicians into an international multidisciplinary specialty. Advancements throughout the next several decades have led to the completion of over 70,000 lung transplants worldwide. The unique challenges presented by patients with end-stage lung disease have both evolved and remained consistent since then, yet these challenges are being answered with major improvements and advancements in perioperative care in the 21st century. The current practice of LTx medicine is fundamentally multidisciplinary, and members of the LTx team includes surgeons, physicians, and allied health staff. The integration of anesthesiologists into the LTx team as well as the multidisciplinary nature of LTx necessitates anesthetic considerations to be closely incorporated into emerging surgical, medical, and systems techniques for patient care. This review discusses a host of emerging strategies across the spectrum of LTx, including efforts to expand the donor pool, utilization of perioperative extracorporeal life support, perioperative echocardiography, and anesthetic techniques to mitigate primary graft dysfunction that have all contributed to improved long term outcomes in LTx patients.

Extracorporeal membrane oxygenation bridge to pediatric lung transplantation: Modern era analysis

BACKGROUND

Survival outcomes of children on extracorporeal membrane oxygenation (ECMO) at time of lung transplant (LTx) remain unclear.

METHODS

Pediatric first-time LTx recipients transplanted between January 2000 and December 2020 were identified in the United Network for Organ Sharing Registry to compare post-transplant survival according to ECMO support at time of transplant. For a comprehensive analysis of the data, univariate analysis, multivariable Cox regression, and propensity score matching were performed.

RESULTS

During the study period, 954 children under 18 years of age underwent LTx with 40 patients on ECMO. We did not identify a post-LTx survival difference between patients receiving ECMO when compared to those that did not. A multivariable Cox regression model (Hazard ratio = 0.83; 95% confidence interval: 0.47, 1.45; p = .51) did not demonstrate an increased risk for death post-LTx. Lastly, a propensity score matching analysis, retaining 33 ECMO and 33 non-ECMO patients, further confirmed no post-LTx survival difference comparing ECMO to no ECMO cohorts (Hazard ratio = 0.98; 95% confidence interval: 0.48, 2.00; p = .96).

CONCLUSIONS

In this contemporary cohort of children, the use of ECMO at the time of LTx did not negatively impact post-transplant survival.

Perioperative Circulatory Support and Management for Lung Transplantation: A Case-Based Review

Lung transplantation (LTx) historically was performed with cardiopulmonary bypass (CPB) or Off-pump. Recent data suggest an increased interest in extracorporeal membrane oxygenation (ECMO) as perioperative circulatory support by many lung transplantation centers worldwide. However, there are no established guidelines for anesthetic management for LTx. We present a patient with a history of systemic sclerosis and interstitial lung disease complicated by acute onset of systemic pulmonary hypertension and right heart failure undergoing LTx. We aim to discuss perioperative circulatory support, including ECMO bridge to LTx, and how best to consider the varied intraoperative strategies of CPB vs ECMO vs off-pump during LTx, intraoperative maintenance, and coagulation management.

Discontinuation of ECMO-a review with a note on Indian scenario

Extracorporeal membrane oxygenation (ECMO) has strikingly progressed over the last 20 years in the management of adult and pediatric severe respiratory and cardiac dysfunctions refractory to conventional management. In this review, we will discuss the weaning strategies of veno-venous and veno-arterial ECMO including the bridge to recovery and bridge to transplant along with post-ECMO care. We will also discuss the futility and the management of bridge to nowhere from Indian perspectives.

Extracorporeal carbon dioxide removal for acute respiratory failure: a review of potential indications, clinical practice and open research questions

Extracorporeal carbon dioxide removal (ECCO₂R) is a form of extracorporeal life support (ECLS) largely aimed at removing carbon dioxide in patients with acute hypoxemic or acute hypercapnic respiratory failure, so as to minimize respiratory acidosis, allowing more lung protective ventilatory settings which should decrease ventilator-induced lung injury. ECCO₂R is increasingly being used despite the lack of high-quality evidence, while complications associated with the technique remain an issue of concern. This review explains the physiological basis underlying the use of ECCO₂R, reviews the evidence regarding indications and contraindications, patient management and complications, and addresses organizational and ethical considerations. The indications and the risk-to-benefit ratio of this technique should now be carefully evaluated using structured national or international registries and large randomized trials.

Favorable, arduous or fatal postoperative pathway within 90 days of lung transplantation

INTRODUCTION

The maximum gain in quality of life after lung transplantation (LT) is expected between six months and one year after LT, as the occurrence of chronic lung allograft dysfunction may mask the beneficial effects beyond one year. Thus, the postoperative period could be the cornerstone of graft success. We sought to describe the factors present before postoperative admission to the ICU and associated with favorable, arduous or fatal pathway within 90 days of LT.

MATERIALS AND METHODS

We conducted a retrospective single-center study between January 2015 and December 2020. Using multinomial regression, we assessed the demographic, preoperative and intraoperative characteristics of patients associated with favorable (duration of postoperative mechanical ventilation < 3 days and alive at Day 90), arduous (duration of postoperative mechanical ventilation ≥ 3 days and alive at Day 90) or fatal (dead at Day 90) pathway within 90 days of LT.

RESULTS

A total of 269 lung transplant patients were analyzed. Maximum graft cold ischemic time ≥ 6 h and intraoperative blood transfusion ≥ 3 packed red blood cells were associated with arduous and fatal pathway at Day 90, whereas intraoperative ECMO was strongly associated with fatal pathway.

CONCLUSION

No patient demographics influenced the postoperative pathway at Day 90. Only extrinsic factors involving graft ischemia time, intraoperative transfusion, and intraoperative ECMO determined early postoperative pathway.

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.

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.

Current trends in candidate selection, contraindications, and indications for lung transplantation

Lung transplantation is an established treatment option that can improve quality of life and prolong survival for select patients diagnosed with end-stage lung disease. Given the gaps in organ donation and failures to make effective use of available organs, careful selection of candidates for lung transplant remains one of the most important considerations of the transplant community. Toward this end, we briefly reviewed recent trends in pretransplant evaluation, candidate selection, organ allocation, and organ preservation techniques. Since the latest consensus statement regarding appropriate selection of lung transplant candidates, many advances in the science and practice of lung transplantation have emerged and influenced our perspective of 'contraindications' to transplant. These advances have made it increasingly possible to pursue lung transplant in patients with risk factors for decreased survival-namely, older recipient age, increased body mass index, previous chest surgery, poorer nutritional status, and presence of chronic infection, cardiovascular disease, or extrapulmonary comorbid conditions. Therefore, we reviewed the updated evidence demonstrating the prognostic impact of these risk factors in lung transplant recipients. Lastly, we reviewed the salient evidence for current trends in disease-specific indications for lung transplantation, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, emphysema due to alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension, among other less common end-stage diseases. Overall, lung transplant remains an exciting field with considerable hope for patients as they experience remarkable improvements in quality of life and survival in the modern era.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

TOPIC

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

CLINICAL RELEVANCE

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

PURPOSE OF PAPER

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

CONTENT COVERED

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

Selection Criteria for Lung Transplantation: Controversies and New Developments

Lung transplantation is an accepted therapeutic option for end-stage lung diseases. The imbalance between limited availability and vast need of donor organs necessitates careful selection of recipient candidates, ensuring the best possible utilization of the scarce resource of organs. Nonetheless, possible lung transplant candidates who could experience a meaningful improvement in survival and quality of life should not be excluded solely based on the complexity of their case. In this review, controversial issues or difficult limitations for lung transplantation, and new developments in recipient selection criteria, are discussed, which may help broaden recipient eligibility for lung transplantation without compromising long-term outcomes.

Critical care of patients with pulmonary arterial hypertension

PURPOSE OF REVIEW

Need for intensive care in the patient with pulmonary arterial hypertension is associated with high mortality. This review will provide an overview of causes of ICU admission for patients with pulmonary hypertension and provide guidance on management.

RECENT FINDINGS

There is a paucity of evidence-based medical literature on management of patients with pulmonary arterial hypertension. This article will summarize the available literature and expert guidance on the topic. Patients with pulmonary arterial hypertension may require ICU care as a direct consequence of decompensated right heart failure. Alternatively, patients with pulmonary arterial hypertension may be affected by the myriad of maladies encountered every day in the ICU including acute respiratory failure, septic shock, and gastrointestinal bleeding. The treatment plan should focus on identifying and treating the cause for decompensation. In addition, optimization of right ventricular preload, reduction of right ventricular afterload, correction of hypotension and augmentation of right ventricular inotropy should be considered.

SUMMARY

The approach to ICU care of patients with pulmonary arterial hypertension requires special consideration with regard to intubation and mechanical ventilation and management of volume status and hemodynamics. Whenever possible, these patients should be transferred to centers with experience in treating this complex, vulnerable population.

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.

Extracorporeal membrane oxygenation and lung transplantation

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

Artificial lungs--Where are we going with the lung replacement therapy?

Lung transplantation may be a final destination therapy in lung failure, but limited donor organ availability creates a need for alternative management, including artificial lung technology. This invited review discusses ongoing developments and future research pathways for respiratory assist devices and tissue engineering to treat advanced and refractory lung disease. An overview is also given on the aftermath of the coronavirus disease 2019 pandemic and lessons learned as the world comes out of this situation. The first order of business in the future of lung support is solving the problems with existing mechanical devices. Interestingly, challenges identified during the early days of development persist today. These challenges include device-related infection, bleeding, thrombosis, cost, and patient quality of life. The main approaches of the future directions are to repair, restore, replace, or regenerate the lungs. Engineering improvements to hollow fiber membrane gas exchangers are enabling longer term wearable systems and can be used to bridge lung failure patients to transplantation. Progress in the development of microchannel-based devices has provided the concept of biomimetic devices that may even enable intracorporeal implantation. Tissue engineering and cell-based technologies have provided the concept of bioartificial lungs with properties similar to the native organ. Recent progress in artificial lung technologies includes continued advances in both engineering and biology. The final goal is to achieve a truly implantable and durable artificial lung that is applicable to destination therapy.

Developments in lung transplantation over the past decade

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

The impact of obesity on outcomes in patients receiving extracorporeal life support

Extracorporeal life support (ECLS) has been increasingly utilized to manage cardiac and pulmonary dysfunction. The impact of obesity on outcomes of ECLS is poorly defined. The purpose of the study was to compare in-hospital mortality, resource use, complications, and readmissions in obese versus non-obese patients receiving ECLS. We performed a retrospective cohort study of all adult ECLS patients with and without an obesity diagnosis using the 2010-2016 Nationwide Readmissions Database (NRD). Mortality, length of stay (LOS), hospital charges, complications, and readmissions were evaluated using multivariable logistic and linear regression. Of 23 876, patients who received ECLS, 1924 (8.1%) were obese. Obese patients received ECLS more frequently for respiratory failure (29.5% vs. 23.7%, P = .001). After adjustment for patient and hospital factors, obesity was not associated with increased odds of mortality (AOR = 1.06, P = .44) and was associated with decreased LOS (13.7 vs. 21.2 days, P < .001), hospital charges ($171 866 vs. $211 445, P < .001), and 30-day readmission (AOR = 0.71, P = .03). Obesity was also associated with reduced odds of hemorrhage (AOR = 0.43, P < .001), neurologic complications (AOR = 0.55, P = .004), and acute kidney injury (AOR=0.83, P = .04). After stratification by ECLS indication, obesity remained predictive of shorter LOS (AOR range: 0.53-0.78, all P < .05 ) and did not impact mortality (all P > .05). Respiratory support remains the most common indication for ECLS among obese patients. Among all patients, as well as by individual ECLS indication, obesity was not associated with increased odds of mortality. These findings suggest that obesity should not be considered a high-risk contraindication to ECLS.

Bridging to Lung Transplantation

Lung transplantation is the gold standard for treating patients with end-stage lung disease. Such patients can present with severe illness on the waitlist and may deteriorate before a lung donor is available. Bridging strategies with extracorporeal membrane oxygenation (ECMO) are valuable for getting patients to transplant and provide a chance at survival. The current article describes the indications, contraindications, and techniques involved in bridging to lung transplantation with ECMO.

Double-lung versus heart-lung transplantation for precapillary pulmonary arterial hypertension: a 24-year single-center retrospective study

Transplant type for end-stage pulmonary vascular disease remains debatable. We compared recipient outcome after heart-lung (HLT) versus double-lung (DLT) transplantation. Single-center analysis (38 HLT-30 DLT; 1991-2014) for different causes of precapillary pulmonary hypertension (PH): idiopathic (22); heritable (two); drug-induced (nine); hepato-portal (one); connective tissue disease (four); congenital heart disease (CHD) (24); chronic thromboembolic PH (six). HLT decreased from 91.7% [1991-1995] to 21.4% [2010-2014]. Re-intervention for bleeding was higher after HLT; (P = 0.06) while primary graft dysfunction grades 2 and 3 occurred more after DLT; (P < 0.0001). Graft survival at 90 days, 1, 5, 10, and 15 years was 93%, 83%, 70%, 47%, and 35% for DLT vs. 82%, 74%, 61%, 48%, and 30% for HLT, respectively (log-rank P = 0.89). Graft survival improved over time: 100%, 93%, 87%, 72%, and 72% in [2010-2014] vs. 75%, 58%, 42%, 33%, and 33% in [1991-1995], respectively; P = 0.03. No difference in chronic lung allograft dysfunction (CLAD)-free survival was observed: 80% & 28% for DLT vs. 75% & 28% for HLT after 5 and 10 years, respectively; P = 0.49. Primary graft dysfunction in PH patients was lower after HLT compared to DLT. Nonetheless, overall graft and CLAD-free survival were comparable and improved over time with growing experience. DLT remains our preferred procedure for all forms of precapillary PH, except in patients with complex CHD.

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

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

National trends in volume-outcome relationships for extracorporeal membrane oxygenation

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) has emerged as a common therapy for severe cardiopulmonary dysfunction. We aimed to describe the relationship of institutional volume with patient outcomes and examine transfer status to tertiary ECMO centers.

MATERIALS AND METHODS

Using the National Inpatient Sample, we identified adult patients who received ECMO from 2008 to 2014. Individual hospital volume was calculated as tertiles of total institutional discharges for each year independently.

RESULTS

Of the total 18,684 adult patients placed on ECMO, 2548 (13.6%), 5278 (28.2%), and 10,858 (58.1%) patients were admitted to low-, medium-, and high-volume centers, respectively. Unadjusted mortality at low-volume hospitals was less than that of medium- (43.7% versus 50.3%, P = 0.03) and high-volume hospitals (43.7% versus 55.6%, P < 0.001). Length of stay and cost were reduced at low-volume hospitals compared to both medium- and large-volume institutions (all P < 0.001). In high-volume institutions, transferred patients had greater postpropensity-matched mortality (58.5% versus 53.7%, P = 0.05) and cost ($190,299 versus $168,970, P = 0.009) compared to direct admissions. On exclusion of transferred patients from propensity analysis, mortality remained greater in high-volume compared to low-volume centers (50.2% versus 42.8%, P = 0.04). Predictors of mortality included treatment at high-volume centers, respiratory failure, and cardiogenic shock (all P < 0.001).

CONCLUSIONS

Our findings show increased in-hospital mortality in high-volume institutions and in patients transferred to tertiary centers. Whether this phenomenon represents selection bias or transfer from another facility deserves further investigation and will aid with the identification of surrogate markers for quality of high-risk interventions.