Improved waitlist and transplant outcomes for pediatric lung transplantation after implementation of the lung allocation score

Impact of Functional Status at the Time of Transplant on Short-Term Pediatric Lung Transplant Outcomes in the USA

PURPOSE

Poor functional status is associated with pediatric lung transplant (LTx) waitlist mortality. We investigate how pre-transplant functional status affects post-LTx survival.

METHODS

A retrospective analysis was performed using The United Network for Organ Sharing (UNOS) Registry data. Pediatric first-time lung transplant candidates between ages 1 and 18 years with reported Lansky Play-Performance Scores (LPPS) at the time of waitlist and/or transplant were included from 2005 and 2021. Functional status by the LPPS scores is defined as severe limitation for LPPS score 10-40, mild limitation for LPPS score 50-70, and normal activity for LPPS score 80-100. Univariate analyses, multivariable Cox regression, and Kaplan-Meier plots were used to assess the impact of functional status on 1-year post-LTx survival.

RESULTS

There were 913 and 610 patients at the time of LTx listing and transplant with LPPS scores, respectively. Poor functional status as determined by the LPPS score at the time of LTx, but not at the time of waitlist, was associated with worse 1-year post-LTx outcome (p value 0.0025 vs. 0.071). Multivariable survival analysis using Cox proportional hazards regression identified that a severely limited functional status at the time of LTx was the most profound risk factor for worse 1-year post-LTx survival outcomes when compared to a normal functional status (HR 2.16; 95% CI 1.15-4.07, p value 0.017).

CONCLUSIONS

Children with severely limited functional status at the time of LTx have worse 1-year post-LTx outcome. It is important to develop strategies to optimize the functional status of children for improved post-LTx outcomes.

Disparities in lung transplantation in children

Lung transplantation is a recognized therapy for end-stage respiratory failure in children and young people. It is only available in selected countries and is limited by access to suitable organs. Data on disparities in access and outcomes for children undergoing lung transplantation are limited. It is clear from data from studies in adults, and from studies in other solid organ transplants in children, that systemic inequities exist in this field. While data relating specifically to pediatric lung transplantation are relatively sparse, professionals should be aware of the risk that healthcare systems may result in disparities in access and outcomes following lung transplantation in children.

Lobar graft evaluation in cadaveric lobar lung redo transplantation after living-donor lobar lung transplantation: a case report

BACKGROUND

Lung transplantation is a vital option for patients with end-stage lung disease. However, it faces a significant challenge due to the shortage of compatible donors, which particularly affects individuals with small chest cavities and pediatric patients. The novel approach of cadaveric lobar lung transplantation is a promising solution to alleviate the donor shortage crisis. Both the mid-term and long-term outcomes of lobar lung transplantation are comparable to those of standard lung transplantation. However, patients undergoing lobar lung transplantation reported a significantly higher rate of primary graft dysfunction compared to patients undergoing standard lung transplantation. Therefore, careful donor selection is critical to improve outcomes after lobar transplantation. However, no established method exists to evaluate each lung lobar graft of deceased donors. This case report describes a case of cadaveric lobar lung transplantation to overcome size mismatch and donor shortage, with particular emphasis on lobar graft evaluation.

CASE PRESENTATION

A 39-year-old woman with scleroderma-related respiratory failure was listed for deceased donor lung transplantation due to a rapidly progressing disease. Faced with a long waiting list and impending mortality, she underwent bilateral living-donor lobar lung transplantation donated by her relatives. Post-transplant complications included progressive pulmonary vein obstruction and pleural effusion, which ultimately required retransplantation. An oversized donor with pneumonia in the bilateral lower lobes was allocated. Lung ultrasound was used to evaluate each lung lobar graft during procurement. The right upper and middle lobes and left upper lobe were confirmed to be transplantable, and lobar lung redo transplantation was performed. The patient's post-transplant course was uneventful, and she was discharged home and returned to her daily activities.

CONCLUSIONS

This case highlights the clinical impact of cadaveric lobar lung transplantation as a feasible and effective strategy to overcome the shortage of donor lungs, especially in patients with small thoracic cavities. By establishing donor lung evaluation techniques and overcoming anatomical and logistical challenges, cadaveric lobar lung transplantation can significantly expand the donor pool and offer hope to those previously considered ineligible for transplantation.

Lung transplantation in children

Lung transplantation is a well-established treatment for children facing advanced lung disease and pulmonary vascular disorders. However, organ shortage remains highest in children. For fitting the small chest of children, transplantation of downsized adult lungs, lobes, or even segments were successfully established. The worldwide median survival after pediatric lung transplantation is currently 5.7 years, while under consideration of age, underlying disease, and peri- and posttransplant center experience, median survival of more than 10 years is reported. Timing of referral for transplantation, ischemia-reperfusion injury, primary graft dysfunction, and acute and chronic rejection after transplantation remain the main challenges.

Poor functional status at the time of waitlist for pediatric lung transplant is associated with worse pretransplant outcomes

BACKGROUND

Whether functional status is associated with survival to pediatric lung transplant is unknown. We hypothesized that completely dependent functional status at waitlist registration, defined using Lansky Play Performance Scale (LPPS), would be associated with worse outcomes.

METHODS

Retrospective cohort study of pediatric lung transplant registrants utilizing United Network for Organ Sharing's Standard Transplant Analysis and Research files (2005-2020). Primary exposure was completely dependent functional status, defined as LPPS score of 10-40. Primary outcome was waitlist removal for death/deterioration with cause-specific hazard ratio (CSHR) regression. Subdistribution hazard regression (SHR, Fine and Gray) was used for the secondary outcome of waitlist removal due to transplant/improvement with a competing risk of death/deterioration. Confounders included: sex, age, race, diagnosis, ventilator dependence, extracorporeal membrane oxygenation, year, and listing center volume.

RESULTS

A total of 964 patients were included (63.5% ≥ 12 years, 50.2% cystic fibrosis [CF]). Median waitlist days were 95; 20.1% were removed for death/deterioration and 68.2% for transplant/improvement. Completely dependent functional status was associated with removal due to death/deterioration (adjusted CSHR 5.30 [95% CI 2.86-9.80]). This association was modified by age (interaction p = 0.0102), with a larger effect for age ≥12 years, and particularly strong for CF. In the Fine and Gray model, completely dependent functional status did not affect the risk of removal due to transplant/improvement with a competing risk of death/deterioration (adjusted SHR 1.08 [95% CI 0.77-1.49]).

CONCLUSIONS

Pediatric lung transplant registrants with the worst functional status had worse pretransplant outcomes, especially for adolescents and CF patients. Functional status at waitlist registration may be a modifiable risk factor to improve survival to lung transplant.

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.

Bilateral lung transplantation for pediatric pulmonary arterial hypertension: perioperative management and one-year follow-up

Background

Bilateral lung transplantation (LuTx) remains the only established treatment for children with end-stage pulmonary arterial hypertension (PAH). Although PAH is the second most common indication for LuTx, little is known about optimal perioperative management and midterm clinical outcomes.

Methods

Prospective observational study on consecutive children with PAH who underwent LuTx with scheduled postoperative VA-ECMO support at Hannover Medical School from December 2013 to June 2020.

Results

Twelve patients with PAH underwent LuTx (mean age 11.9 years; age range 1.9-17.8). Underlying diagnoses included idiopathic (n = 4) or heritable PAH (n = 4), PAH associated with congenital heart disease (n = 2), pulmonary veno-occlusive disease (n = 1), and pulmonary capillary hemangiomatosis (n = 1). The mean waiting time was 58.5 days (range 1-220d). Three patients were bridged to LuTx on VA-ECMO. Intraoperative VA-ECMO/cardiopulmonary bypass was applied and VA-ECMO was continued postoperatively in all patients (mean ECMO-duration 185 h; range 73-363 h; early extubation). The median postoperative ventilation time was 28 h (range 17-145 h). Echocardiographic conventional and strain analysis showed that 12 months after LuTx, all patients had normal biventricular systolic function. All PAH patients are alive 2 years after LuTx (median follow-up 53 months, range 26-104 months).

Conclusion

LuTx in children with end-stage PAH resulted in excellent midterm outcomes (100% survival 2 years post-LuTx). Postoperative VA-ECMO facilitates early extubation with rapid gain of allograft function and sustained biventricular reverse-remodeling and systolic function after RV pressure unloading and LV volume loading.

Allocation to pediatric recipients around the world: An IPTA global survey of current pediatric solid organ transplantation deceased donation allocation practices

BACKGROUND

There has not been a comprehensive global survey of pediatric-deceased donor allocation practices across all organs since the advent of deceased donor transplantation at the end of the 20th century. As an international community that is responsible for transplanting children, we set out to survey the existing landscape of allocation. We aimed to summarize current practices and provide a snapshot overview of deceased donor allocation practices to children across the world.

METHODS

The International Registry in Organ Donation and Transplantation (IRODAT, www.irodat.org) was utilized to generate a list of all countries in the world, divided by continent, that performed transplantation. We reviewed the published literature, published allocation policy, individual website references and associated links to publicly available listed allocation policies. Following this, we utilized tools of communication, relationships, and international fellowship to confirm deceased donation pediatric centers and survey pediatric allocation practices for liver, kidney, heart, and lung across the world. We summarize pediatric allocation practices by organ when available using source documents, and personal communication when no source documents were available.

RESULTS

The majority of countries had either formal or informal policies directed toward minimizing organ distribution disparity among pediatric patients.

CONCLUSION

Children have long-term life to gain from organ donation yet continue to die while awaiting transplantation. We summarize global strategies that have been employed to provide meaningful and sustained benefit to children on the waitlist.

Deceased donor organ allocation in pediatric transplantation: A historical narrative

BACKGROUND

Since the earliest clinical successes in solid organ transplantation, the proper method of organ allocation for children has been a contentious subject. Over the past 30-35 years, the medical and social establishments of various countries have favored some degree of preference for children on the respective waiting lists. However, the specific policies to accomplish this have varied widely and changed frequently between organ type and country.

METHODS

Organ allocation policies over time were examined. This review traces the reasons behind and the measures/principles put in place to promote early deceased donor transplantation in children.

RESULTS

Preferred allocation in children has been approached in a variety of ways and with varying degrees of commitment in different solid organ transplant disciplines and national medical systems.

CONCLUSION

The success of policies to advantage children has varied significantly by both organ and medical system. Further work is needed to optimize allocation strategies for pediatric candidates.

Extracorporeal membrane oxygenation as a bridge to transplant in neonates with fatal pulmonary conditions: A review

Neonates with progressive respiratory failure should be referred early for subspecialty evaluation and lung transplantation consideration. ECMO should be considered for patients with severe cardiopulmonary dysfunction and a high likelihood of death while on maximal medical therapy, either in the setting of reversible medical conditions or while awaiting lung transplantation. While ECMO offers hope to neonates that experience clinical deterioration while awaiting transplant, the risks and benefits of this intervention should be considered on an individual basis. Owing to the small number of infant lung transplants performed yearly, large studies examining the outcomes of various bridging techniques in this age group do not exist. Multiple single-centre experiences of transplanted neonates have been described and currently serve as guidance for transplant teams. Future investigation of outcomes specific to neonatal transplant recipients bridged with advanced devices is needed.

Seven-day in vivo testing of a novel, low-resistance, pumpless pediatric artificial lung for long-term support

INTRODUCTION

For children with end-stage lung disease that cannot wean from extracorporeal life support (ECLS), a wearable artificial lung would permit extubation and provide a bridge to recovery or transplantation. We evaluate the function of the novel Pediatric MLung-a low-resistance, pumpless artificial lung developed specifically for children-in healthy animal subjects.

METHODS

Adolescent "mini sheep" weighing 12-20 kg underwent left thoracotomy, cannulation of the main pulmonary artery (PA; inflow) and left atrium (outflow), and connection to the MLung.

RESULTS

Thirteen sheep were studied; 6 were supported for 7 days. Mean PA pressure was 23.9 ± 6.9 mmHg. MLung blood flow was 633±258 mL/min or 30.0 ± 16.0% of CO. MLung pressure drop was 4.4 ± 3.4 mmHg. Resistance was 7.2 ± 5.2 mmHg/L/min. Device outlet oxygen saturation was 99.0 ± 3.3% with inlet saturation 53.8 ± 7.3%. Oxygen delivery was 41.1 ± 18.4 mL O₂/min (maximum 84.9 mL/min) or 2.8 ± 1.5 mL O₂/min/kg. Platelet count significantly decreased; no platelet transfusions were required. Plasma free hemoglobin significantly increased only on day 7, at which point 2 of the animals had plasma free hemoglobin levels above 50 mg/dL.

CONCLUSION

The MLung provides adequate gas exchange at appropriate blood flows for the pediatric population in a PA-to-LA configuration. Further work remains to improve the biocompatibility of the device.

LEVEL OF EVIDENCE

N/A.

Extracorporeal membrane oxygenation and paracorporeal lung assist devices as a bridge to pediatric lung transplantation

BACKGROUND

"Bridging" is a term used to describe the implementation of various treatment modalities to improve waitlist survival while a patient awaits lung transplantation. ECMO and PLAD are technologies used to bridge patients to lung transplantation. ECMO and PLAD are cardiopulmonary support systems that help move blood forward while using an artificial membrane to remove CO₂ from and add O₂ to the blood. Recent studies showed that these technologies are increasingly effective in bridging patients to lung transplantation, especially with optimizing patient selection, implementing physical rehabilitation and ambulation goals, standardization of management decisions, and increasing staff experience, among other considerations. We review these technologies, their roles as bridges to pediatric lung transplantation, as well as indications, contraindications, complications, and mortality rates.

CONCLUSION

Finally, we discuss the existing knowledge gaps and areas for future research to improve patient outcomes and understanding of lung assist devices.

A pumpless artificial lung without systemic anticoagulation: The Nitric Oxide Surface Anticoagulation system

BACKGROUND

Artificial lungs have the potential to serve as a bridge to transplantation or recovery for children with end-stage lung disease dependent on extracorporeal life support, but such devices currently require systemic anticoagulation. We describe our experience using the novel Nitric Oxide (NO) Surface Anticoagulation (NOSA) system-an NO-releasing circuit with NO in the sweep gas-with the Pediatric MLung-a low-resistance, pumpless artificial lung.

METHODS

NO flux testing: MLungs (n = 4) were tested using veno-venous extracorporeal life support in a sheep under anesthesia with blood flow set to 0.5 and 1 L/min and sweep gas blended with 100 ppm NO at 1, 2, and 4 L/min. NO and NO₂ were measured in the sweep and exhaust gas to calculate NO flux across the MLung membrane. Pumpless implants: Sheep (20-100 kg, n = 3) underwent thoracotomy and cannulation via the pulmonary artery (device inflow) and left atrium (device outflow) using cannulae and circuit components coated with an NO donor (diazeniumdiolated dibutylhexanediamine; DBHD-N₂O₂) and argatroban. Animals were connected to the MLung with 100 ppm NO in the sweep gas under anesthesia for 24 h with no systemic anticoagulation after cannulation.

RESULTS

NO flux testing: NO flux averaged 3.4 ± 1.0 flux units (x10^-10 mol/cm²/min) (human vascular endothelium: 0.5-4 flux units). Pumpless implants: 3 sheep survived 24 h with patent circuits. MLung blood flow was 716 ± 227 mL/min. Outlet oxygen saturation was 98.3 ± 2.6%. Activated clotting time was 151±24 s. Platelet count declined from 334,333 ± 112,225 to 123,667 ± 7,637 over 24 h. Plasma free hemoglobin and leukocyte and platelet activation did not significantly change.

CONCLUSIONS

The NOSA system provides NO flux across a gas-exchange membrane of a pumpless artificial lung at a similar rate as native vascular endothelium and achieves effective local anticoagulation of an artificial lung circuit for 24 h.

Pediatric heart-lung transplantation: Technique and special considerations

Heart-lung transplantation has historically been used as a definitive treatment for children with end-stage cardiopulmonary failure, although the number performed has steadily decreased over time. In this review, we discuss current indications, preoperative risk factors, outcomes, and heart-lung transplantation in unique patient subsets, including infants, children with single-ventricle physiology, tetralogy of Fallot/major aortopulmonary collateral arteries, and prior Potts shunt palliation. We also describe the different surgical techniques utilized in pediatric heart-lung transplantation.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Mortality after Lung Transplantation for Children Bridged with Extracorporeal Membrane Oxygenation

RATIONALE

Extracorporeal membrane oxygenation (ECMO) is increasingly used to bridge waitlisted children failing conventional respiratory support to lung transplantation.

OBJECTIVES

To compare in-hospital mortality and a composite outcome of 1-year mortality or re-transplantation in children bridged with ECMO with those on mechanical ventilation (MV), and neither support.

METHODS

The United Network for Organ Sharing (UNOS) was used to analyze lung transplant recipients, aged ≤ 20 y, from January 2004 to August 2019. Recipients were categorized according to level of respiratory support at time of transplant, including ECMO, MV, or neither. Multivariable analysis was used to evaluate support type and in-hospital mortality.

RESULTS

Of 1,014 children undergoing lung transplant, 68 (6.7%) required ECMO as a bridge-to-transplant, 144 (14.2%) MV, and 802 (79.1%) neither. Primary diagnosis in the ECMO cohort included cystic fibrosis (43%), pneumonia/ARDS (10.3%), interstitial pulmonary fibrosis (7.4%) and pulmonary hypertension (5.9%). Number of patients bridged with ECMO increased throughout the study period from none in 2004 to 16.7% in 2018. Multivariable analysis showed bridging with both ECMO (aOR = 3.57; 95% CI: 1.42, 8.97) and MV (aOR = 2.67; 95% CI: 1.26, 5.57) increased in-hospital mortality after lung transplantation. However, there was no difference in composite outcome of mortality and re-transplantation at 1-year between the three groups.

CONCLUSIONS

ECMO to bridge children to lung transplantation has increased. Despite this, ECMO is a high-risk bridge strategy for children awaiting lung transplantation. Future research should target interventions that can be focused on improving survival in these patients.

The Lung Allocation Score and Its Relevance

Lung transplantation in the United States, under oversight by the Organ Procurement Transplantation Network (OPTN) in the 1990s, operated under a system of allocation based on location within geographic donor service areas, wait time of potential recipients, and ABO compatibility. On May 4, 2005, the lung allocation score (LAS) was implemented by the OPTN Thoracic Organ Transplantation Committee to prioritize patients on the wait list based on a balance of wait list mortality and posttransplant survival, thus eliminating time on the wait list as a factor of prioritization. Patients were categorized into four main disease categories labeled group A (obstructive lung disease), B (pulmonary hypertension), C (cystic fibrosis), and D (restrictive lung disease/interstitial lung disease) with variables within each group impacting the calculation of the LAS. Implementation of the LAS led to a decrease in the number of wait list deaths without an increase in 1-year posttransplant survival. LAS adjustments through the addition, modification or elimination of covariates to improve the estimates of patient severity of illness, have since been made in addition to establishing criteria for LAS value exceptions for pulmonary hypertension patients. Despite the success of the LAS, concerns about the prioritization, and transplantation of older, sicker individuals have made some aspects of the LAS controversial. Future changes in US lung allocation are anticipated with the current development of a continuous distribution model that incorporates the LAS, geographic distribution, and unaccounted aspects of organ allocation into an integrated score.

Lung and heart-lung transplantation for children with PAH: Dramatic benefits from the implementation of a high-priority allocation program in France

PURPOSE

Pulmonary arterial hypertension (PAH) is rare but remains fatal in infants and children despite the advance of targeted therapies. Lung transplantation (LTx), first performed in pediatric patients in the 1980s, is, with the Potts shunt, the only potentially life-extending option in patients with end-stage PAH but is possible only in tightly selected patients. Size-matching challenges severely restrict the donor organ pool, resulting-together with peculiarities of PAH in infants-in high waitlist mortality. We aimed to investigate survival when using a high-priority allocation program (HPAP) in children with PAH listed for double-LTx or heart-LTx.

METHODS

We conducted a single-center, retrospective, before-after study of consecutive children with severe Group 1 PAH listed for double-LTx or heart-LTx between 1988 and 2019. The HPAP was implemented in France in 2006 and 2007 for heart-LTx and double-LTx, respectively.

RESULTS

Fifty-five children with PAH were listed for transplantation. Mean age at transplantation was 15.8±2.8 years and 72% had heart-lung transplantation. PAH was usually idiopathic (65%) or due to congenital heart disease (25%). HPAP implementation resulted in the following significant benefits: Decreased cumulative incidence of waitlist death within 1 and 2 years (p < 0.0001); increased cumulative incidence of transplantation within 6 months, from 44% to 67% (p < 0.01); and improved survival after listing (at 1, 3, and 5 years: 61%, 50%, and 44% vs. 92%, 84%, and 72% before and after HPAP implementation, respectively; p = 0.02).

CONCLUSION

HPAP implementation was associated with significant improvements in access to transplantation and in survival after listing in children with end-stage PAH.

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.

Pediatric and neonatal extracorporeal life support: current state and continuing evolution

The use of extracorporeal life support (ECLS) for the pediatric and neonatal population continues to grow. At the same time, there have been dramatic improvements in the technology and safety of ECLS that have broadened the scope of its application. This article will review the evolving landscape of ECLS, including its expanding indications and shrinking contraindications. It will also describe traditional and hybrid cannulation strategies as well as changes in circuit components such as servo regulation, non-thrombogenic surfaces, and paracorporeal lung-assist devices. Finally, it will outline the modern approach to managing a patient on ECLS, including anticoagulation, sedation, rehabilitation, nutrition, and staffing.

Surgical considerations in infant lung transplantation: Challenges and opportunities

Lung transplantation is a crucial component in the treatment of end-stage lung disease in infants. Traditionally, most lung transplants have been performed in older children and adults, resulting in a scarcity of data for infant patients. To address the challenges unique to this age group, novel strategies to provide the best preoperative, intraoperative, and postoperative care for these youngest patients are paramount. We review recent advances in bridge-to-transplantation therapy, including the use of a paracorporeal lung assist device, and differences in surgical technique, including bronchial artery revascularization, for incorporation into the overarching treatment strategy for infants undergoing lung transplantation.

Pediatric lung transplantation as standard of care

For infants, children, and adolescents with progressive advanced lung disease, lung transplantation represents the ultimate therapy option. Fortunately, outcomes after pediatric lung transplantation have improved in recent years now producing good long-term outcomes, no less than comparable to adult lung transplantation. The field of pediatric lung transplantation has rapidly advanced; thus, this review aims to update on important issues such as transplant referral and assessment, and extra-corporal life support as "bridge to transplantation". In view of the ongoing lack of donor organs limiting the success of pediatric lung transplantation, donor acceptability criteria and surgical options of lung allograft size reduction are discussed. Post-transplant, immunosuppression is vital for prevention of allograft rejection; however, evidence-based data on immunosuppression are scarce. Drug-related side effects are frequent, close therapeutic drug monitoring is highly advised with an individually tailored patient approach. Chronic lung allograft dysfunction (CLAD) remains the Achilles' heel of pediatric lung transplant limiting its long-term success. Unfortunately, therapy options for CLAD are still restricted. The last option for progressive CLAD would be consideration for lung re-transplant; however, numbers of pediatric patients undergoing lung re-transplantation are very small and its success depends highly on the optimal selection of the most suitable candidate.

Clinical outcomes and survival following lung transplantation in patients with pulmonary Langerhans cell histiocytosis

BACKGROUND AND OBJECTIVE

Disease-specific outcomes following lung transplantation (LT) in patients with pulmonary Langerhans cell histiocytosis (PLCH) are not well established. We queried the Organ Procurement and Transplantation Network database to identify adult PLCH patients who had undergone LT in the United States.

METHODS

Overall survival data were analysed with Kaplan-Meier curves. Cox proportional hazard model was used to determine the effect of demographic, clinical and physiological variables on post-transplant survival.

RESULTS

A total of 87 patients with PLCH underwent LT in the United States between October 1987 and June 2017, accounting for 0.25% of the total LT during this period. The mean age at LT for PLCH patients was 49 years (range: 19-67 years), with a near equal gender distribution. Bilateral sequential LT was performed in 71 patients (82%). Pulmonary hypertension was present in 85% of patients, with a mean pulmonary artery pressure of 38.5 ± 14.1 mm Hg. The mean pre-transplant forced expiratory volume in 1 s (FEV₁ ) was 41 ± 21% predicted and the mean 6-min walk distance was 221 ± 111 m. Median post-LT survival for PLCH patients was comparable to patients with other lung diseases (5.1 vs 5.5 years, P = 0.76). The actuarial Kaplan-Meier post-LT survival for PLCH patients was 85%, 65%, 49% and 22% at 1, 3, 5 and 10 years, respectively. Female sex (hazard ratio (HR): 0.40, 95% CI: 0.22-0.72), pre-transplant serum bilirubin (HR: 1.66, 95% CI: 1.23-2.26) and serum creatinine (HR: 4.03, 95% CI: 1.01-14.76) were independently associated with post-LT mortality in our cohort.

CONCLUSION

Post-LT survival in patients with PLCH is similar to patients with other lung diseases and is significantly affected by patient gender.

Clinical outcomes and survival following lung transplantation in patients with lymphangioleiomyomatosis

BACKGROUND

The primary aim of our study was to derive disease-specific outcomes following lung transplantation (LT) in patients with lymphangioleiomyomatosis (LAM).

METHODS

We queried the Organ Procurement and Transplant Network database to identify LAM patients that have undergone LT in the United States. The overall survival was analyzed with Kaplan-Meier curves. Survival estimates between subgroups of interest were compared using the log-rank method. Cox proportional hazard models were employed to determine the pre-transplant variables that impact post-LT survival.

RESULTS

One hundred and thirty-eight women with LAM underwent LT at 31 centers between January 2003 and June 2017. The median age at listing and transplant was 44 (IQR: 36-51) and 45 (IQR: 38-52) years, respectively. The median time spent on the LT waitlist was 257 (IQR: 85-616) days. The majority of the patients (109/134, 81%) received bilateral sequential LT. The median ischemic time was 4.9 (IQR: 4.1-6.1) hours. The actuarial Kaplan-Meier survival following LT for LAM patients at 1-, 5-, and 10 years was 94%, 73% and 56%, respectively. The post-LT survival was significantly better in LAM than in other lung diseases (10-year survival 56% vs. 32%, p < 0.01), and this advantage persisted after age- and gender-matched analysis (10-year survival 54% vs. 37%, p < 0.01). Pre-transplant parameters, such as the presence of pulmonary hypertension, six-minute walk distance, age at transplant, ischemic time during transplant, or type of transplant (single vs bilateral sequential LT), did not affect post-transplant survival.

CONCLUSIONS

The median survival after LT in LAM is 12 years and is substantially better than in other lung diseases.

State of the Art in Pediatric Lung Transplantation

Pediatric lung transplantation is a highly specialized therapy for end-stage pulmonary disease in children, and is performed in only a handful of transplant centers around the world. Advancement in the field has been made on many fronts in recent years, including in public policy and organ allocation strategies, donor selection and management, emerging technologies for donor lung rehabilitation and bridge-to-transplant support of listed candidates, and ongoing refinement of surgical techniques. Despite this progress, children continue to suffer discrepant waitlist mortality and longer waiting times than their adult counterparts, and face special challenges of donor availability and size matching. Here, we assess the current state of the art in pediatric lung transplantation, reviewing progress made to date and further opportunities to improve care for this unique group of patients.

Pediatric lung transplantation and end of life care in cystic fibrosis: Barriers and successful strategies

Pediatric lung transplantation has advanced over the years, providing a potential life-prolonging therapy to patients with cystic fibrosis. Despite this, many challenges in lung transplantation remain and result in worse outcomes than other solid organ transplants. As CF lung disease progresses, children and their caregivers are often simultaneously preparing for lung transplantation and end of life. In this article, we will discuss the current barriers to success in pediatric CF lung transplantation as well as approaches to end of life care in this population.

Pediatric lung transplantation

Pediatric lung transplantation is a highly specialized clinical endeavor. Since the late 1980's, there have only been slightly more than 2200 implants reported to the International Society for Heart and Lung transplantation registry. This review will discuss the historical aspects of pediatric lung transplantation. It will familiarize the reader with the current indications for transplant and the referral and listing process. The current state of lung assist devices as a bridge to pediatric lung transplantation is discussed in addition to the technical aspects of the transplant procedure. Finally, posttransplant outcomes, including anticipated morbidity and the role of retransplantation, are clarified.