Primary graft failure following lung transplantation

Contemporary trends in PGD incidence, outcomes, and therapies

BACKGROUND

We sought to describe trends in extracorporeal membrane oxygenation (ECMO) use, and define the impact on PGD incidence and early mortality in lung transplantation.

METHODS

Patients were enrolled from August 2011 to June 2018 at 10 transplant centers in the multi-center Lung Transplant Outcomes Group prospective cohort study. PGD was defined as Grade 3 at 48 or 72 hours, based on the 2016 PGD ISHLT guidelines. Logistic regression and survival models were used to contrast between group effects for event (i.e., PGD and Death) and time-to-event (i.e., death, extubation, discharge) outcomes respectively. Both modeling frameworks accommodate the inclusion of potential confounders.

RESULTS

A total of 1,528 subjects were enrolled with a 25.7% incidence of PGD. Annual PGD incidence (14.3%-38.2%, p = .0002), median LAS (38.0-47.7 p = .009) and the use of ECMO salvage for PGD (5.7%-20.9%, p = .007) increased over the course of the study. PGD was associated with increased 1 year mortality (OR 1.7 [95% C.I. 1.2, 2.3], p = .0001). Bridging strategies were not associated with increased mortality compared to non-bridged patients (p = .66); however, salvage ECMO for PGD was significantly associated with increased mortality (OR 1.9 [1.3, 2.7], p = .0007). Restricted mean survival time comparison at 1-year demonstrated 84.1 days lost in venoarterial salvaged recipients with PGD when compared to those without PGD (ratio 1.3 [1.1, 1.5]) and 27.2 days for venovenous with PGD (ratio 1.1 [1.0, 1.4]).

CONCLUSIONS

PGD incidence continues to rise in modern transplant practice paralleled by significant increases in recipient severity of illness. Bridging strategies have increased but did not affect PGD incidence or mortality. PGD remains highly associated with mortality and is increasingly treated with salvage ECMO.

CD11b suppresses TLR activation of nonclassical monocytes to reduce primary graft dysfunction after lung transplantation

Primary graft dysfunction (PGD) is the leading cause of postoperative mortality in lung transplant recipients and the most important risk factor for development of chronic lung allograft dysfunction. The mechanistic basis for the variability in the incidence and severity of PGD between lung transplant recipients is not known. Using a murine orthotopic vascularized lung transplant model, we found that redundant activation of Toll-like receptors 2 and 4 (TLR2 and -4) on nonclassical monocytes activates MyD88, inducing the release of the neutrophil attractant chemokine CXCL2. Deletion of Itgam (encodes CD11b) in nonclassical monocytes enhanced their production of CXCL2 and worsened PGD, while a CD11b agonist, leukadherin-1, administered only to the donor lung prior to lung transplantation, abrogated CXCL2 production and PGD. The damage-associated molecular pattern molecule HMGB1 was increased in peripheral blood samples from patients undergoing lung transplantation after reperfusion and induced CXCL2 production in nonclassical monocytes via TLR4/MyD88. An inhibitor of HMGB1 administered to the donor and recipient prior to lung transplantation attenuated PGD. Our findings suggest that CD11b acts as a molecular brake to prevent neutrophil recruitment by nonclassical monocytes following lung transplantation, revealing an attractive therapeutic target in the donor lung to prevent PGD in lung transplant recipients.

Lymphocytic Airway Inflammation in Lung Allografts

Lung transplant remains a key therapeutic option for patients with end stage lung disease but short- and long-term survival lag other solid organ transplants. Early ischemia-reperfusion injury in the form of primary graft dysfunction (PGD) and acute cellular rejection are risk factors for chronic lung allograft dysfunction (CLAD), a syndrome of airway and parenchymal fibrosis that is the major barrier to long term survival. An increasing body of research suggests lymphocytic airway inflammation plays a significant role in these important clinical syndromes. Cytotoxic T cells are observed in airway rejection, and transcriptional analysis of airways reveal common cytotoxic gene patterns across solid organ transplant rejection. Natural killer (NK) cells have also been implicated in the early allograft damage response to PGD, acute rejection, cytomegalovirus, and CLAD. This review will examine the roles of lymphocytic airway inflammation across the lifespan of the allograft, including: 1) The contribution of innate lymphocytes to PGD and the impact of PGD on the adaptive immune response. 2) Acute cellular rejection pathologies and the limitations in identifying airway inflammation by transbronchial biopsy. 3) Potentiators of airway inflammation and heterologous immunity, such as respiratory infections, aspiration, and the airway microbiome. 4) Airway contributions to CLAD pathogenesis, including epithelial to mesenchymal transition (EMT), club cell loss, and the evolution from constrictive bronchiolitis to parenchymal fibrosis. 5) Protective mechanisms of fibrosis involving regulatory T cells. In summary, this review will examine our current understanding of the complex interplay between the transplanted airway epithelium, lymphocytic airway infiltration, and rejection pathologies.

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.

A Focused Review on Primary Graft Dysfunction after Clinical Lung Transplantation: A Multilevel Syndrome

Primary graft dysfunction (PGD) is the clinical syndrome of acute lung injury after lung transplantation (LTx). However, PGD is an umbrella term that encompasses the ongoing pathophysiological and -biological mechanisms occurring in the lung grafts. Therefore, we aim to provide a focused review on the clinical, physiological, radiological, histological and cellular level of PGD. PGD is graded based on hypoxemia and chest X-ray (CXR) infiltrates. High-grade PGD is associated with inferior outcome after LTx. Lung edema is the main characteristic of PGD and alters pulmonary compliance, gas exchange and circulation. A conventional CXR provides a rough estimate of lung edema, while a chest computed tomography (CT) results in a more in-depth analysis. Macroscopically, interstitial and alveolar edema can be distinguished below the visceral lung surface. On the histological level, PGD correlates to a pattern of diffuse alveolar damage (DAD). At the cellular level, ischemia-reperfusion injury (IRI) is the main trigger for the disruption of the endothelial-epithelial alveolar barrier and inflammatory cascade. The multilevel approach integrating all PGD-related aspects results in a better understanding of acute lung failure after LTx, providing novel insights for future therapies.

Application of Mesenchymal Stem Cells During Machine Perfusion: An Emerging Novel Strategy for Organ Preservation

Although solid organ transplantation remains the definitive management for patients with end-stage organ failure, this ultimate treatment has been limited by the number of acceptable donor organs. Therefore, efforts have been made to expand the donor pool by utilizing marginal organs from donation after circulatory death or extended criteria donors. However, marginal organs are susceptible to ischemia-reperfusion injury (IRI) and entail higher requirements for organ preservation. Recently, machine perfusion has emerged as a novel preservation strategy for marginal grafts. This technique continually perfuses the organs to mimic the physiologic condition, allows the evaluation of pretransplant graft function, and more excitingly facilitates organ reconditioning during perfusion with pharmacological, gene, and stem cell therapy. As mesenchymal stem cells (MSCs) have anti-oxidative, immunomodulatory, and regenerative properties, mounting studies have demonstrated the therapeutic effects of MSCs on organ IRI and solid organ transplantation. Therefore, MSCs are promising candidates for organ reconditioning during machine perfusion. This review provides an overview of the application of MSCs combined with machine perfusion for lung, kidney, liver, and heart preservation and reconditioning. Promising preclinical results highlight the potential clinical translation of this innovative strategy to improve the quality of marginal grafts.

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.

Interobserver variability in the evaluation of primary graft dysfunction after lung transplantation: impact of radiological training and analysis of discordant cases

PURPOSE

Radiologic criteria for the diagnosis of primary graft dysfunction (PGD) after lung transplantation are nonspecific and can lead to misinterpretation. The primary aim of our study was to assess the interobserver agreement in the evaluation of chest X-rays (CXRs) for PGD diagnosis and to establish whether a specific training could have an impact on concordance rates. Secondary aim was to analyze causes of interobserver discordances.

MATERIAL AND METHODS

We retrospectively enrolled 164 patients who received bilateral lung transplantation at our institution, between February 2013 and December 2019. Three radiologists independently reviewed postoperative CXRs and classified them as suggestive or not for PGD. Two of the Raters performed a specific training before the beginning of the study. A senior thoracic radiologist subsequently analyzed all discordant cases among the Raters with the best agreement. Statistical analysis to calculate interobserver variability was percent agreement, Cohen's kappa and intraclass correlation coefficient.

RESULTS

A total of 473 CXRs were evaluated. A very high concordance among the two trained Raters, 1 and 2, was found (K = 0.90, ICC = 0.90), while a poorer agreement was found in the other two pairings (Raters 1 and 3: K = 0.34, ICC = 0.40; Raters 2 and 3: K = 0.35, ICC = 0.40). The main cause of disagreement (52.4% of discordant cases) between Raters 1 and 2 was the overestimation of peribronchial thickening in the absence of unequivocal bilateral lung opacities or the incorrect assessment of unilateral alterations.

CONCLUSION

To properly identify PGD, it is recommended for radiologists to receive an adequate specific training.

Clinical features and outcomes of combined pulmonary fibrosis and emphysema after lung transplantation

BACKGROUND

Combined pulmonary fibrosis and emphysema (CPFE) is recognized as a characteristic syndrome of smoking-related interstitial lung disease that has a worse prognosis than idiopathic pulmonary fibrosis (IPF). However, outcomes after lung transplantation for CPFE have not been reported. The aim of this study is to describe the clinical features and outcomes of CPFE after lung transplantation.

RESEARCH QUESTION

What are the clinical features and outcomes of CPFE after lung transplantation?

STUDY DESIGN AND METHODS

This is a single-center retrospective cohort study of patients with CPFE and IPF who underwent lung transplantation at our center between January 2011 and December 2016. We defined CPFE as ≥ 10% emphysema in the upper lung fields combined with fibrosis on high-resolution computed tomography scan. We characterized the clinical features of patients with CPFE and compared their outcomes after lung transplantation to those with IPF.

RESULTS

27 of 172 (16%) patients with IPF met criteria for CPFE. Severe pulmonary hypertension was present in 16 of 27 (59%) patients with CPFE. On logistic regression analysis, CPFE was significantly associated with primary graft dysfunction (PGD) grade 3 (odds ratio: 3.14, 95% confidence interval [CI]: 1.18-8.37, p=0.02). On competing risk regression analysis, CPFE was associated with acute cellular rejection (ACR) grade ≥ A2, and chronic lung allograft dysfunction (CLAD) (hazard ratio [HR]: 1.89, 95% CI: 1.10-3.25, p=0.02, HR: 1.96, 95% CI: 1.02-3.77, p=0.04, respectively). 5-year survival was 79.0% for the CPFE group and 75.4% for the IPF group, respectively (log rank p = 0.684).

INTERPRETATION

After transplant, patients with CPFE were more likely to develop PGD, ACR, and CLAD compared to those with IPF. However, survival was not significantly different between the 2 groups.

Primary Graft Dysfunction

Primary graft dysfunction (PGD) is a form of acute lung injury after transplantation characterized by hypoxemia and the development of alveolar infiltrates on chest radiograph that occurs within 72 hours of reperfusion. PGD is among the most common early complications following lung transplantation and significantly contributes to increased short-term morbidity and mortality. In addition, severe PGD has been associated with higher 90-day and 1-year mortality rates compared with absent or less severe PGD and is a significant risk factor for the subsequent development of chronic lung allograft dysfunction. The International Society for Heart and Lung Transplantation released updated consensus guidelines in 2017, defining grade 3 PGD, the most severe form, by the presence of alveolar infiltrates and a ratio of PaO₂:FiO₂ less than 200. Multiple donor-related, recipient-related, and perioperative risk factors for PGD have been identified, many of which are potentially modifiable. Consistently identified risk factors include donor tobacco and alcohol use; increased recipient body mass index; recipient history of pulmonary hypertension, sarcoidosis, or pulmonary fibrosis; single lung transplantation; and use of cardiopulmonary bypass, among others. Several cellular pathways have been implicated in the pathogenesis of PGD, thus presenting several possible therapeutic targets for preventing and treating PGD. Notably, use of ex vivo lung perfusion (EVLP) has become more widespread and offers a potential platform to safely investigate novel PGD treatments while expanding the lung donor pool. Even in the presence of significantly prolonged ischemic times, EVLP has not been associated with an increased risk for PGD.

Machine perfusion of donor organs for transplantation

The ever-widening gap between organ supply and demand has resulted in an organ shortage crisis that affects patients all over the world. For decades, static cold storage (SCS) was the gold standard preservation strategy because of its simplicity and cost-effectiveness, but the rising unmet demand for donor organ transplants has prompted investigation into preservation strategies that can expand the available donor pool. Through ex vivo functional assessment of the organ prior to transplant, newer methods to preserve organs such as perfusion-based therapy can potentially expand the available organ pool. This review will explain the physiologic rationale for SCS before exploring the advantages and disadvantages associated with the two broad classes of preservation strategies that have emerged to address the crisis: hypothermic and normothermic machine perfusion. A detailed analysis of how each preservation strategy works will be provided before investigating the current status of clinical data for each preservation strategy for the kidney, liver, pancreas, heart, and lung. For some organs there is robust data to support the use of machine perfusion technologies over SCS, and in others the data are less clear. Nonetheless, machine perfusion technologies represent an exciting frontier in organ preservation research and will remain a crucial component of closing the gap between organ supply and recipient demand.

Lung Innate Lymphoid Cell Composition Is Altered in Primary Graft Dysfunction

Rationale: Primary graft dysfunction (PGD) is the leading cause of early morbidity and mortality after lung transplantation, but the immunologic mechanisms are poorly understood. Innate lymphoid cells (ILC) are a heterogeneous family of immune cells regulating pathologic inflammation and beneficial tissue repair. However, whether changes in donor-derived lung ILC populations are associated with PGD development has never been examined.Objectives: To determine whether PGD in chronic obstructive pulmonary disease or interstitial lung disease transplant recipients is associated with alterations in ILC subset composition within the allograft.Methods: We performed a single-center cohort study of lung transplantation patients with surgical biopsies of donor tissue taken before, and immediately after, allograft reperfusion. Donor immune cells from 18 patients were characterized phenotypically by flow cytometry for single-cell resolution of distinct ILC subsets. Changes in the percentage of ILC subsets with reperfusion or PGD (grade 3 within 72 h) were assessed.Measurements and Main Results: Allograft reperfusion resulted in significantly decreased frequencies of natural killer cells and a trend toward reduced ILC populations, regardless of diagnosis (interstitial lung disease or chronic obstructive pulmonary disease). Seven patients developed PGD (38.9%), and PGD development was associated with selective reduction of the ILC2 subset after reperfusion. Conversely, patients without PGD exhibited significantly higher ILC1 frequencies before reperfusion, accompanied by elevated ILC2 frequencies after allograft reperfusion.Conclusions: The composition of donor ILC subsets is altered after allograft reperfusion and is associated with PGD development, suggesting that ILCs may be involved in regulating lung injury in lung transplant recipients.

Fortification of Preservation Solution With Nitroprusside Does Not Alter Lung Allograft Survival in Clinical Human Lung Transplantation

Background: Nitric oxide improves gas exchange following primary lung allograft dysfunction. Nitroprusside, a potent nitric oxide donor, has reduced reperfusion injury and improved oxygenation in experimental lung transplantation. Methods: We sought to study the effect on lung allograft outcomes of fortifying the preservation solution with nitroprusside. We conducted a single-center clinical study of 46 consecutive lung recipients between 1998 and 2000: 24 patients received donor organs preserved in modified Euro-Collins solution with prostaglandin E1 (PGE1) (control group), and 22 patients received organs preserved in modified Euro-Collins with PGE1 and nitroprusside (NP group). The primary endpoint was overall survival. Results: Baseline characteristics were similar between the groups except for a significantly longer graft ischemic time in the NP group vs the control group (253.3 ± 52 vs 225.3 ± 41 minutes, respectively, P=0.04). No significant differences were found in partial pressure arterial oxygen to fraction inspired oxygen ratio at ≤48 hours, primary graft dysfunction, or bronchiolitis obliterans-free days. Overall survival at 1, 3, and 5 years was 89%, 73%, and 63% in the control group and 76%, 38%, and 23% in the NP group. Log-rank survival analysis showed that the NP group had a significantly increased risk of mortality (P=0.034) compared to the control group. Conclusion: The addition of nitroprusside to the lung transplant perfusate in this clinical trial did not improve survival; however, a large randomized trial would likely reduce confounding ischemia times and increase the power of the study.

Inhaled Pulmonary Vasodilators and Thoracic Organ Transplantation: Does Evidence Support Its Use and Cost Benefit?

In heart transplantation, pulmonary hypertension and increased pulmonary vascular resistance followed by donor right ventricular dysfunction remain a major cause of perioperative morbidity and mortality. In lung transplantation, primary graft dysfunction remains a major obstacle because it can cause bronchiolitis obliterans and mortality. Pulmonary vasodilators have been used as an adjunct therapy for heart or lung transplantation, mainly to treat pulmonary hypertension, right ventricular failure, and associated refractory hypoxemia. Among pulmonary vasodilators, inhaled nitric oxide is unique in that it is selective in pulmonary circulation and causes fewer systemic complications such as hypotension, flushing, or coagulopathy. Nitric oxide is expected to prevent or attenuate primary graft dysfunction by decreasing ischemia-reperfusion injury in lung transplantation. However, when considering the long-term benefit of these medications, little evidence supports their use in heart or lung transplantation. Current guidelines endorse inhaled vasodilators for managing immediate postoperative right ventricular failure in lung or heart transplantation, but no guidance is offered regarding agent selection, dosing, or administration. This review presents the current evidence of inhaled nitric oxide in lung or heart transplantation as well as comparisons with other pulmonary vasodilators including cost differences in consideration of economic pressures to contain rising pharmacy costs.

Adipose tissue quantification and primary graft dysfunction after lung transplantation: The Lung Transplant Body Composition study

BACKGROUND

Obesity is associated with an increased risk of primary graft dysfunction (PGD) after lung transplantation. The contribution of specific adipose tissue depots is unknown.

METHODS

We performed a prospective cohort study of adult lung transplant recipients at 4 U.S. transplant centers. We measured cross-sectional areas of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) on chest and abdominal computed tomography (CT) scans and indexed each measurement to height.² We used logistic regression to examine the associations of adipose indices and adipose classes with grade 3 PGD at 48 or 72 hours, and Cox proportional hazards models to examine survival. We used latent class analyses to identify the patterns of adipose distribution. We examined the associations of adipose indices with plasma biomarkers of obesity and PGD.

RESULTS

A total of 262 and 117 subjects had available chest CT scans and underwent protocol abdominal CT scans, respectively. In the adjusted models, a greater abdominal SAT index was associated with an increased risk of PGD (odds ratio 1.9, 95% CI 1.02-3.4, p = 0.04) but not with survival time. VAT indices were not associated with PGD risk or survival time. A greater abdominal SAT index correlated with greater pre- and post-transplant leptin (r = 0.61, p < 0.001, and r = 0.44, p < 0.001), pre-transplant IL-1RA (r = 0.25, p = 0.04), and post-transplant ICAM-1 (r = 0.25, p = 0.04). We identified 3 latent patterns of adiposity. The class defined by high thoracic and abdominal SAT had the greatest risk of PGD.

CONCLUSIONS

Subcutaneous, but not visceral, adiposity is associated with an increased risk of PGD after lung transplantation.

The ex vivo human lung: research value for translational science

Respiratory diseases are among the leading causes of death and disability worldwide. However, the pathogenesis of both acute and chronic lung diseases remains incompletely understood. As a result, therapeutic options for important clinical problems, including acute respiratory distress syndrome and chronic obstructive pulmonary disease, are limited. Research efforts have been held back in part by the difficulty of modeling lung injury in animals. Donor human lungs that have been rejected for transplantation offer a valuable alternative for understanding these diseases. In 2007, our group developed a simple preparation of an ex vivo-perfused single human lung. In this Review, we discuss the availability of donor human lungs for research, describe the ex vivo-perfused lung preparation, and highlight how this preparation can be used to study the mechanisms of lung injury, to isolate primary cells, and to test novel therapeutics.

Pig lung transplant survival model

Although lung transplant is a life-saving therapy for some patients, primary graft dysfunction (PGD) is a leading cause of mortality and morbidity soon after a transplant. Ischemia reperfusion injury is known to be one of the most critical factors in PGD development. PGD is by definition an acute lung injury syndrome that occurs during the first 3 d following lung transplantation. To successfully translate laboratory discoveries to clinical practice, a reliable and practical large animal model is critical. This protocol describes a surgical technique for swine lung transplantation and postoperative management for a further 3 d post transplant. The protocol includes the background and rationale, required supplies, and a detailed description of the donor operation, transplant surgery, postoperative care, and sacrifice surgery. A pig lung transplant model is reliably produced in which the recipients survive for 3 d post transplant. This 3-d survival model can be used by lung transplant researchers to assess the development of PGD and to test therapeutic strategies targeting PGD. In total, the protocol requires 5 h for the surgeries, plus ~2 h in total for the postoperative care.

The effect of primary graft dysfunction after lung transplantation on parenchymal remodeling detected by quantitative computed tomography

Background

Regional analysis by computed tomography (CT) is an attractive technique to interpret lung patterns after transplantation (LTx). We evaluated the application of CT functional mask derived parameters to determine whether development of primary graft dysfunction (PGD) is associated with short and/or long-term postoperative evidences of pulmonary function alterations.

Methods

A total of 38 patients who underwent bilateral LTx were evaluated at 24, 48 and 72 hours after the end of surgery to establish PGD occurrence and grading. CT scans at 3 and 12 months after LTx were analyzed to measure specific gas volume (SV_g) changes normalized on expiratory SVgEXP of the whole lung (ΔSV_g/SV_gEXP) and to obtain functional masks of density variation, namely maps of low ventilation (LV), consolidation (C), air trapping (AT) and healthy parenchyma (H).

Results

Our main result was the evidence of a marked decrease in ΔSV_g/SV_gEXP in all subjects, irrespectively on PGD, at each time point after LTx, indicating a high degree of ventilation defects versus healthy. High percentages of LV were found in all subjects while percentages of AT and C were negligible.

Conclusions

We demonstrate that quantification of ventilation defects by CT functional mask offers insights into the correlation between PGD and pulmonary function after LTx at short and mid-term.

Incidence of Massive Transfusion and Overall Transfusion Requirements During Lung Transplantation Over a 25-Year Period

OBJECTIVE

To establish the incidence of massive transfusion and overall transfusion requirements during lung transplantation, changes over time, and association with outcome in relation to patient complexity.

DESIGN

Retrospective cohort study.

SETTING

University hospital.

PARTICIPANTS

All 514 adult patients who underwent transplantation from 1990 until 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient records and transfusion data, divided into 5-year intervals, were analyzed. The incidence of massive transfusion (>10 units of red blood cells [RBCs] in 24 h) was 27% and did not change over time, whereas the median (interquartile range) transfusion requirement in the whole cohort decreased from 8 (5-12) to 3 (0-10) RBCs (p < 0.001). In patients transplanted from the intensive care unit, the incidence of massive transfusion increased over time from 25% to 54% (p = 0.04) and median transfusion requirements from 4.5 (3-8.5) units to 14.5 (5-26) units of RBCs (p = 0.03). Multivariable analysis showed that circulatory support, pulmonary hypertension, re-transplantation, cystic fibrosis, Eisenmenger syndrome, bilateral transplantation, and low body mass index were associated with massive transfusion. Patients with massive transfusion had more primary graft dysfunction grade III at 0, 24, 48, and 72 hours (p < 0.001), higher 30-day mortality (13% v 4%; p < 0.001), and lower 5-year survival (hazard ratio 3.67 [95% confidence interval 1.72-7.85]; p < 0.001).

CONCLUSION

The incidence of massive transfusion did not change over time, whereas transfusion requirements in the whole cohort decreased. In patients transplanted from the intensive care unit, massive transfusion and transfusion requirements increased. Massive transfusion was associated with poor outcome.

National Heart, Lung, and Blood Institute and American Association for Thoracic Surgery Workshop Report: Identifying collaborative clinical research priorities in lung transplantation

This report summarizes the discussion and recommendations from the June 2017 NHLBI-AATS Workshop on Identifying Collaborative Clinical Research Priorities in Lung Transplantation.

Lung Transplantation in Cystic Fibrosis and the Impact of Extracorporeal Circulation

INTRODUCTION

Lung disease is the major cause of death among cystic fibrosis (CF) patients, affecting 80% of the population. The impact of extracorporeal circulation (ECC) during transplantation has not been fully clarified. This study aimed to evaluate the outcomes of lung transplantation for CF in a single center, and to assess the impact of ECC on survival.

METHODS

We performed a retrospective observational study of all trasplanted CF patients in a single center between 1992 and 2011. During this period, 64 lung transplantations for CF were performed.

RESULTS

Five- and 10-year survival of trasplanted patients was 56.7% and 41.3%, respectively. Pre-transplantation supplemental oxygen requirements and non-invasive mechanical ventilation (NIMV) do not seem to affect survival (P=.44 and P=.63, respectively). Five- and 10-year survival among patients who did not undergo ECC during transplantation was 75.69% and 49.06%, respectively, while in those did undergo ECC during the procedure, 5- and 10-year survival was 34.14% and 29.87%, respectively (P=.001). PaCO₂ is an independent risk factor for the need for ECC.

CONCLUSIONS

The survival rates of CF patients undergoing lung transplantation in our hospital are similar to those described in international registries. Survival is lower among patients receiving ECC during the procedure. PaCO₂ is a risk factor for the need for ECC during lung transplantation.

Evaluation of Cardiac Index and Extravascular Lung Water After Single-Lung Transplantation Using the Transpulmonary Thermodilution Technique by the PiCCO2 Device

OBJECTIVES

First evaluation of the transpulmonary thermodilution technique by the PiCCO2 device to assess cardiac index and pulmonary edema during the postoperative course after single-lung transplantation.

DESIGN

Prospective observational study.

SETTINGS

Intensive care unit, university hospital (single center).

PARTICIPANTS

Single-lung transplant patients.

INTERVENTIONS

The authors compared cardiac index measured by PiCCO2 and pulmonary artery catheter and assessed pulmonary edema using extravascular lung water index and pulmonary vascular permeability index measured by PiCCO2.

MEASUREMENTS AND MAIN RESULTS

A Bland-Altman method was used to compare cardiac index measured by PiCCO2 and pulmonary artery catheter. Extravascular lung water index and pulmonary vascular permeability index were compared according to the PaO₂/FiO₂ ratio with a threshold value of 150 mmHg. Ten single-lung transplant patients were included. Cardiac index measured by PiCCO2 and pulmonary artery catheter were 3.3 L/min/m² (2.9-3.6) and 2.5 L/min/m² (2.2-3.0). Bias for cardiac index was 0.71 L/min/m² (-0.03; 1.44) and limit of agreements were -0.03 and 1.44 L/min/m². Extravascular lung water index was 12 mL/kg (11-16) and pulmonary vascular permeability index was 2.3 (2.0-3.1), consistent with pulmonary edema. Extravascular lung water index was higher in the group of PaO₂/FiO₂ ratio ≤150 mmHg compared with the group of PaO₂/FiO₂ ratio >150 mmHg (17 v 12 mL/kg, p = 0.04), whereas pulmonary vascular permeability index only tended to be higher (3.1 v 2.1, p = 0.06).

CONCLUSION

PiCCO2 device systematically overestimated cardiac index compared with pulmonary artery catheter. However, it might be useful to assess pulmonary edema in acute respiratory failure after single-lung transplantation.

Primary Graft Dysfunction After Lung Transplantation

Primary graft dysfunction is a form of acute injury after lung transplantation that is associated with significant short- and long-term morbidity and mortality. Multiple mechanisms contribute to the pathogenesis of primary graft dysfunction, including ischemia reperfusion injury, epithelial cell death, endothelial cell dysfunction, innate immune activation, oxidative stress, and release of inflammatory cytokines and chemokines. This article reviews the epidemiology, pathogenesis, risk factors, prevention, and treatment of primary graft dysfunction.

Anesthesia for Lung Transplantation

Perioperative management of patients undergoing lung transplantation is challenging and requires constant communication among the surgical, anesthesia, perfusion, and nursing teams. Although all aspects of anesthetic management are important, certain intraoperative strategies (mechanical ventilation, fluid management, extracorporeal mechanical support deployment) have tremendous impact on the subsequent evolution of the lung transplant recipient, especially with respect to allograft function, and should be carefully considered. This review highlights some of the intraoperative anesthetic challenges and opportunities during lung transplantation.

Development of a Multivariate Prediction Model for Early-Onset Bronchiolitis Obliterans Syndrome and Restrictive Allograft Syndrome in Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction and its main phenotypes, bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS), are major causes of mortality after lung transplantation (LT). RAS and early-onset BOS, developing within 3 years after LT, are associated with particularly inferior clinical outcomes. Prediction models for early-onset BOS and RAS have not been previously described.

METHODS

LT recipients of the French and Swiss transplant cohorts were eligible for inclusion in the SysCLAD cohort if they were alive with at least 2 years of follow-up but less than 3 years, or if they died or were retransplanted at any time less than 3 years. These patients were assessed for early-onset BOS, RAS, or stable allograft function by an adjudication committee. Baseline characteristics, data on surgery, immunosuppression, and year-1 follow-up were collected. Prediction models for BOS and RAS were developed using multivariate logistic regression and multivariate multinomial analysis.

RESULTS

Among patients fulfilling the eligibility criteria, we identified 149 stable, 51 BOS, and 30 RAS subjects. The best prediction model for early-onset BOS and RAS included the underlying diagnosis, induction treatment, immunosuppression, and year-1 class II donor-specific antibodies (DSAs). Within this model, class II DSAs were associated with BOS and RAS, whereas pre-LT diagnoses of interstitial lung disease and chronic obstructive pulmonary disease were associated with RAS.

CONCLUSION

Although these findings need further validation, results indicate that specific baseline and year-1 parameters may serve as predictors of BOS or RAS by 3 years post-LT. Their identification may allow intervention or guide risk stratification, aiming for an individualized patient management approach.

A data science approach for quantifying spatio-temporal effects to graft failures in organ transplantation

The transplantation of solid organs is one of the most important accomplishments of modern medicine. Yet, organ shortage is a major public health issue; 8,000 people died while waiting for an organ in 2014. Meanwhile, the allocation system currently implemented can lead to organs being discarded and the medical community still investigates factors that affects early graft failure such as distance and ischemic time. In this paper, we investigate early graft failure under a spatio-temporal perspective using a data science unified approach for all six organs that is based on complementary cumulative analysis of both distance and ischemic time. Interestingly, although distance seems to highly affect some organs (e.g. liver), it appears to have no effect on others (e.g. kidney). Similarly, the results on ischemic time confirm it affects early graft failure with higher influence for some organs such as (e.g. heart) and lower influence for others such as (e.g. kidney). This poses the question whether the allocation policies should be individually designed for each organ in order to account for their particularities as shown in this work.

Lung inflation with hydrogen sulfide during the warm ischemia phase ameliorates injury in rat donor lungs via metabolic inhibition after cardiac death

BACKGROUND

Hydrogen sulfide attenuates lung ischemia-reperfusion injury when inhaled or administered intraperitoneally. This study investigated the effects of lung inflation with H₂S during the warm ischemia phase on lung grafts from rat donors after cardiac death.

METHODS

One hour after cardiac death, donor lungs were inflated in situ for 2 h with either O₂ or H₂S (O₂ or H₂S group) during the warm ischemia phase or were deflated as a control procedure (n = 8). After 3 h of cold preservation, lung transplantation was performed. During the warm ischemia phase, the metabolism and mitochondrial structures of donor lungs were analyzed. Arterial blood gas analysis was performed on the recipients. Protein expression in the graft of nuclear factor E2-related factor (Nrf)2 and nuclear factor kappa B (NF-κB) was analyzed by Western blotting, and static compliance, inflammation, oxidative stress, and cell apoptosis were assessed after 3 h of reperfusion.

RESULTS

When the O₂ and H₂S groups were compared with the control group, the mitochondrial structures were improved, and lactic acid levels, inflammation, oxidative stress, and cell apoptosis were significantly decreased; and glucose levels, as well as graft oxygenation and static compliance were increased. Simultaneously, the above indices showed further improvements, and the Nrf2 protein expression was significantly greater, and NF-κB protein expression was less in the H₂S group than the O₂ group.

CONCLUSION

Lung inflation with H₂S during the warm ischemia phase inhibited metabolism in donor lungs via mitochondrial protection, attenuated graft ischemic-reperfusion injury, and improved graft function through NF-κB-dependent anti-inflammatory and Nrf2-dependent antioxidative and antiapoptotic effects.

Significant role for microRNA-21 affecting toll-like receptor pathway in primary graft dysfunction after human lung transplantation

BACKGROUND

MicroRNAs (miRNAs) were recently identified as modulators of immune responses after human lung transplantation (LTx). This study was undertaken to assess the contribution of miRNAs to the pathogenesis of primary graft dysfunction (PGD) after LTx.

METHODS

Of the 39 recipients, 14 (35.9%) developed Grade 3 PGD (i.e., severe PGD) within the first 72 hours of LTx. The remaining 25 recipients (64.1%) had Grade 2 or less PGD, and served as the control group. miRNAs were isolated from cells purified by bronchoalveolar lavage (BAL). Bioinformatic prediction and validation by luciferase reporter assays were performed to identify targets regulated by miR-21. Transfection of human monocytic cell line (THP-1) was conducted to determine miR-21's cellular function.

RESULTS

Pilot miRNA profiling of donor BAL samples before implantation in PGD (n = 6) revealed significant upregulation in 44 miRNAs and downregulation in 80 miRNAs compared with control (n = 6). Validation using a separate cohort demonstrated significant underexpression of miR-21 in patients with severe PGD. Furthermore, underexpression of miR-21 levels was negatively correlated with clinical PGD grades (Grade 2 PGD vs Grade 0 PGD: p = 0.042; Grade 3 PGD vs Grade 0 PGD: p = 0.004). Molecular analysis demonstrated that miR-21 targeted key components in the toll-like receptor (TLR) signaling pathway, including TLR4, IRAK3 and CXCL10. Further, incubation of THP-1 cells with cell-free BAL from severe PGD resulted in transactivation of inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). In contrast, increased expression of miR-21 resulted in marked suppression of IL-1-β and TNF-α production.

CONCLUSIONS

Underexpression of miR-21 may lead to the development of severe PGD by activating key components of the TLR pathway.

Primary graft dysfunction: Long-term physical function outcomes among lung transplant recipients

BACKGROUND

Adults with primary graft dysfunction (PGD) after lung transplantation are at increased risk for pulmonary and functional impairment. No prior studies have described the long-term (within 1.5 years of transplant) cardiopulmonary exercise testing (CPET) results in adults with grade 3 PGD. The objective of this study was to compare the functional outcomes of lung transplant patients with and without grade 3 PGD via CPET and six-minute talk tests (6MWD).

METHODS

243 adults underwent lung transplantation between 2003 and 2010, 128 (53%) of whom underwent CPET and 6MWD within 12-18 months of transplantation. The primary measure of exposure was grade 3 PGD at 72 h, however grade 3 PGD within 72 h was also assessed. In addition, the impact of potential confounding variables was explored.

RESULTS

Approximately one-third (32%) of the 243 patients experienced grade 3 PGD within 72 h; among these, 15 (6%) had grade 3 PGD at the 72 h time point. There were no differences in CPET or 6MWD between those with and without grade 3 PGD at 72 h despite a longer length of hospital stay and lower pulmonary function. Similar results were seen for patients with and without grade 3 PGD within 72 h, with the exception of a lower heart rate on CPET.

CONCLUSIONS

Participants with grade 3 PGD are able to achieve functional outcomes comparable to those without PGD.

The relationship between plasma lipid peroxidation products and primary graft dysfunction after lung transplantation is modified by donor smoking and reperfusion hyperoxia

BACKGROUND

Donor smoking history and higher fraction of inspired oxygen (FIO2) at reperfusion are associated with primary graft dysfunction (PGD) after lung transplantation. We hypothesized that oxidative injury biomarkers would be elevated in PGD, with higher levels associated with donor exposure to cigarette smoke and recipient hyperoxia at reperfusion.

METHODS

We performed a nested case-control study of 72 lung transplant recipients from the Lung Transplant Outcomes Group cohort. Using mass spectroscopy, F2-isoprostanes and isofurans were measured in plasma collected after transplantation. Cases were defined in 2 ways: grade 3 PGD present at day 2 or day 3 after reperfusion (severe PGD) or any grade 3 PGD (any PGD).

RESULTS

There were 31 severe PGD cases with 41 controls and 35 any PGD cases with 37 controls. Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (28.6 pg/ml vs 19.8 pg/ml, p = 0.03). Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (29.6 pg/ml vs 19.0 pg/ml, p = 0.03) among patients reperfused with FIO2 >40%. Among recipients of lungs from donors with smoke exposure, plasma F2-isoprostane (38.2 pg/ml vs 22.5 pg/ml, p = 0.046) and isofuran (66.9 pg/ml vs 34.6 pg/ml, p = 0.046) levels were higher in severe PGD compared with control subjects.

CONCLUSIONS

Plasma levels of lipid peroxidation products are higher in patients with severe PGD, in recipients of lungs from donors with smoke exposure, and in recipients exposed to higher Fio2 at reperfusion. Oxidative injury is an important mechanism of PGD and may be magnified by donor exposure to cigarette smoke and hyperoxia at reperfusion.

Pretreatment with bone marrow-derived mesenchymal stromal cell-conditioned media confers pulmonary ischemic tolerance

OBJECTIVE

Mesenchymal stromal cell-based therapies have demonstrated efficacy in treating a variety of diseases. Despite the potential benefits, there are still significant hurdles that need to be overcome for clinical use. We describe a cell-free-based immunotherapy approach for inducing pulmonary ischemic tolerance by using mesenchymal stromal cell-conditioned media.

METHODS

In our well-established lung ischemia-reperfusion model, we pretreated with mesenchymal stromal cell-conditioned media 30 minutes before injury. To determine the degree of lung injury, we assessed for changes in lung vascular permeability, proinflammatory cytokines and cellular infiltrates in bronchoalveolar lavage, and histopathology. Macrophage and T-cell subsets were assessed by immunohistochemistry.

RESULTS

Pretreatment with mesenchymal stromal cell-conditioned media conferred protection against lung ischemia-reperfusion injury. This protection is characterized by a significant reduction in proinflammatory cytokines, a decrease in infiltrating inflammatory cells, and increases in M2-like macrophages and regulatory T cells.

CONCLUSIONS

Cell-free mesenchymal stromal cell-conditioned media therapy confers pulmonary ischemic tolerance. This therapy uses paracrine factors that provide beneficial protective effects by immunomodulating the inflammatory response in resident and infiltrating cell subsets.

Primary graft dysfunction: lessons learned about the first 72 h after lung transplantation

PURPOSE OF REVIEW

In 2005, the International Society for Heart and Lung Transplantation published a standardized definition of primary graft dysfunction (PGD), facilitating new knowledge on this form of acute lung injury that occurs within 72 h of lung transplantation. PGD continues to be associated with significant morbidity and mortality. This article will summarize the current literature on the epidemiology of PGD, pathogenesis, risk factors, and preventive and treatment strategies.

RECENT FINDINGS

Since 2011, several manuscripts have been published that provide insight into the clinical risk factors and pathogenesis of PGD. In addition, several transplant centers have explored preventive and treatment strategies for PGD, including the use of extracorporeal strategies. More recently, results from several trials assessing the role of extracorporeal lung perfusion may allow for much-needed expansion of the donor pool, without raising PGD rates.

SUMMARY

This article will highlight the current state of the science regarding PGD, focusing on recent advances, and set a framework for future preventive and treatment strategies.

Role of innate immunity in primary graft dysfunction after lung transplantation

PURPOSE OF REVIEW

Primary graft dysfunction (PGD), a form of acute lung injury after lung transplantation, has a significant impact on clinical outcomes after lung transplantation. This potentially reversible graft impairment occurs after ischemia-reperfusion injury. This review describes the expanding body of literature evaluating the central role of innate immune activation, nonadaptive responses and dysregulation in the development of PGD after lung transplant.

RECENT FINDINGS

The innate immune system, highlighted by Toll-like receptor pathways and neutrophil migration and influx, plays an important role in the initiation and propagation of ischemia-reperfusion injury. Recent plasma biomarker and gene association studies have identified several genes and proteins composing innate immune pathways to be associated with PGDs. Long pentraxin-3 and Toll-like receptors, as well as inflammasomes and Toll-interacting protein, are associated with the development of PGD after lung transplantation.

SUMMARY

Innate immune pathways are involved in the development of PGD and may provide attractive targets for therapies. It may be possible to prevent or treat PGD, as well as to allow pre-transplant PGD risk stratification. To improve understanding of the mechanisms behind clinical risk factors for PGD will require further in-depth correlation of donor-specific and recipient-related triggers of nonadaptive immune responses.

Microvesicles Derived From Human Mesenchymal Stem Cells Restore Alveolar Fluid Clearance in Human Lungs Rejected for Transplantation

The need to increase the donor pool for lung transplantation is a major public health issue. We previously found that administration of mesenchymal stem cells "rehabilitated" marginal donor lungs rejected for transplantation using ex vivo lung perfusion. However, the use of stem cells has some inherent limitation such as the potential for tumor formation. In the current study, we hypothesized that microvesicles, small anuclear membrane fragments constitutively released from mesenchymal stem cells, may be a good alternative to using stem cells. Using our well established ex vivo lung perfusion model, microvesicles derived from human mesenchymal stem cells increased alveolar fluid clearance (i.e. ability to absorb pulmonary edema fluid) in a dose-dependent manner, decreased lung weight gain following perfusion and ventilation, and improved airway and hemodynamic parameters compared to perfusion alone. Microvesicles derived from normal human lung fibroblasts as a control had no effect. Co-administration of microvesicles with anti-CD44 antibody attenuated these effects, suggesting a key role of the CD44 receptor in the internalization of the microvesicles into the injured host cell and its effect. In summary, microvesicles derived from human mesenchymal stem cells were as effective as the parent mesenchymal stem cells in rehabilitating marginal donor human lungs.

Objective Estimates Improve Risk Stratification for Primary Graft Dysfunction after Lung Transplantation

Primary graft dysfunction (PGD) is a major cause of early mortality after lung transplant. We aimed to define objective estimates of PGD risk based on readily available clinical variables, using a prospective study of 11 centers in the Lung Transplant Outcomes Group (LTOG). Derivation included 1255 subjects from 2002 to 2010; with separate validation in 382 subjects accrued from 2011 to 2012. We used logistic regression to identify predictors of grade 3 PGD at 48/72 h, and decision curve methods to assess impact on clinical decisions. 211/1255 subjects in the derivation and 56/382 subjects in the validation developed PGD. We developed three prediction models, where low-risk recipients had a normal BMI (18.5-25 kg/m(2) ), chronic obstructive pulmonary disease/cystic fibrosis, and absent or mild pulmonary hypertension (mPAP<40 mmHg). All others were considered higher-risk. Low-risk recipients had a predicted PGD risk of 4-7%, and high-risk a predicted PGD risk of 15-18%. Adding a donor-smoking lung to a higher-risk recipient significantly increased PGD risk, although risk did not change in low-risk recipients. Validation demonstrated that probability estimates were generally accurate and that models worked best at baseline PGD incidences between 5% and 25%. We conclude that valid estimates of PGD risk can be produced using readily available clinical variables.

Heart and lung transplantation

PURPOSE OF REVIEW

Every year, thousands of heart and lung transplants are performed worldwide. As experience and clinical acumen advance, both fields are continually evolving. This review elucidates and describes many of the recent changes in practice and future directions of heart and lung transplantation. Preoperative, intraoperative and postoperative developments are presented with supporting evidence in these continually evolving fields.

RECENT FINDINGS

The field of heart transplantation is continually adapting to the growing use of mechanical circulatory support devices as bridge to transplant and for postoperative support. Recent modifications in surgical technique have contributed to improved outcomes.Lung transplantation advancements include the increasing use of extracorporeal membrane oxygenation during the perioperative period. Lobar transplantation and ex-vivo lung perfusion techniques may aid in providing successful lung grafts to those with potentially long wait list times.Rates of rejection continue to decline in both fields as immunosuppression regimens are improved and modified.

SUMMARY

This review investigates and summarizes the recent changes and advancements in heart and lung transplantation. Mechanical circulatory support and extracorporeal membrane oxygenation are increasingly used in the perioperative setting, and continuing research will evaluate their safety profiles. Optimizing and tailoring immunosuppression regimens for transplant recipients continue to be the subject of ongoing investigation.

Shear stress-related mechanosignaling with lung ischemia: lessons from basic research can inform lung transplantation

Cessation of blood flow represents a physical event that is sensed by the pulmonary endothelium leading to a signaling cascade that has been termed "mechanotransduction." This paradigm has clinical relevance for conditions such as pulmonary embolism, lung bypass surgery, and organ procurement and storage during lung transplantation. On the basis of our findings with stop of flow, we postulate that normal blood flow is "sensed" by the endothelium by virtue of its location at the interface of the blood and vessel wall and that this signal is necessary to maintain the endothelial cell membrane potential. Stop of flow is sensed by a "mechanosome" consisting of PECAM-VEGF receptor-VE cadherin that is located in the endothelial cell caveolae. Activation of the mechanosome results in endothelial cell membrane depolarization that in turn leads to activation of NADPH oxidase (NOX2) to generate reactive oxygen species (ROS). Endothelial depolarization additionally results in opening of T-type voltage-gated Ca(2+) channels, increased intracellular Ca(2+), and activation of nitric oxide (NO) synthase with resultant generation of NO. Increased NO causes vasodilatation whereas ROS provide a signal for neovascularization; however, with lung transplantation overproduction of ROS and NO can cause oxidative injury and/or activation of proteins that drive inflammation and cell death. Understanding the key events in the mechanosignaling cascade has important lessons for the design of strategies or interventions that may reduce injury during storage of donor lungs with the goal to increase the availability of lungs suitable for donation and thus improving access to lung transplantation.

C1-esterase-inhibitor for primary graft dysfunction in lung transplantation

BACKGROUND

Primary graft dysfunction (PGD) is the most important cause of early morbidity and mortality in lung transplantation (LTX) with an incidence of 8% to 20%. We hypothesized that application of C1-esterase-inhibitor (C1-INH) in LTX-recipients showing early signs of severe PGD would attenuate the condition.

METHODS

Starting as of May 2010, all recipients showing a PaO2/FiO2 ratio of less than 100 as early sign of PGD at first measurement in the OR were immediately treated with C1-INH. Postoperative courses of C1-INH-treated recipients were compared with a subgroup of recipients that developed severe PGD (PGD3-group) within 72 hours after LTX but did not receive C1-INH. Additionally, a third group consisting of all remaining recipients was assembled.

RESULTS

A total of 275 LTX were performed between May 2010 and September 2012 at our center. Among these, 24 patients (8.7%) revealed a first PaO2/FiO2 ratio less than 100 and were treated with C1-INH (C1-INH-group). The PGD3-group consisted of 14 patients; the control cohort consisted of 237 patients. PGD scores were significantly higher in the C1-INH-group and PGD3-group as compared with the control group at all times postoperatively. ICU stay was longest in the PGD3 cohort and prolonged in C1-INH patients compared with the control group (29 [2-70] vs. 9 [2-83] vs. 3 [1-166] days, P=0.002). One-year survival in the PGD3-cohort was 71.4%, the C1-INH-treated-group had a one-year-survival of 82.5%, the control group had the best outcome (95%) (P=0.001).

CONCLUSION

Treatment of PGD with C1-INH led to acceptable outcome. Although survival in the C1-INH treated patients was lower than in the remaining collective, it was as good or better, compared with the PGD3 group and as what is internationally regarded as reasonable after LTX.