Technical Advances Targeting Multiday Preservation of Isolated Ex Vivo Lung Perfusion.

Indications for ex vivo lung perfusion (EVLP) have evolved from assessment of questionable donor lungs to treatment of some pathologies and the logistics. Yet up to 3 quarters of donor lungs remain discarded across the globe. Multiday preservation of discarded human lungs on EVLP platforms would improve donor lung utilization rates via application of sophisticated treatment modalities, which could eventually result in zero waitlist mortality. The purpose of this article is to summarize advances made on the technical aspects of the protocols in achieving a stable multiday preservation of isolated EVLP. Based on the evidence derived from large animal and/or human studies, the following advances have been considered important in achieving this goal: ability to reposition donor lungs during EVLP; perfusate adsorption/filtration modalities; perfusate enrichment with plasma and/or donor whole blood, nutrients, vitamins, and amino acids; low-flow, pulsatile, and subnormothermic perfusion; positive outflow pressure; injury specific personalized ventilation strategies; and negative pressure ventilation. Combination of some of these advances in an automatized EVLP device capable of managing perfusate biochemistry and ventilation would likely speed up the processes of achieving multiday preservation of isolated EVLP.

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

OBJECTIVES: History of anatomical lung resection complicates lung transplantation (LTx). Our aim was to identify indications, intraoperative approach and outcome in these challenging cases in a retrospective multicentre cohort analysis. METHODS: Members of the ESTS Lung Transplantation Working Group were invited to submit data on patients undergoing LTx after a previous anatomical native lung resection between January 2005 and July 2020. The primary end point was overall survival (Kaplan-Meier estimation). RESULTS: Out of 2690 patients at 7 European centres, 26 (1%) patients (14 males; median age 33 years) underwent LTx after a previous anatomical lung resection. The median time from previous lung resection to LTx was 12 years. The most common indications for lung resection were infections (n = 17), emphysema (n = 5), lung tumour (n = 2) and others (n = 2). Bronchiectasis (cystic fibrosis or non-cystic fibrosis related) was the main indication for LTx (n = 21), followed by COPD (n = 5). Two patients with a previous pneumonectomy underwent contralateral single LTx and 1 patient with a previous lobectomy had ipsilateral single LTx. The remaining 23 patients underwent bilateral LTx. Clamshell incision was performed in 12 (46%) patients. Moreover, LTx was possible without extracorporeal life support in 13 (50%) patients. 90-Day mortality was 8% (n = 2) and the median survival was 8.7 years. CONCLUSIONS: The history of anatomical lung resection is rare in LTx candidates. The majority of patients are young and diagnosed with bronchiectasis. Although the numbers were limited, survival after LTx in patients with previous anatomical lung resection, including pneumonectomy, is comparable to reported conventional LTx for bronchiectasis.

Perfusate adsorption during ex vivo lung perfusion improves early post-transplant lung function.

OBJECTIVE: Improvement in ex vivo lung perfusion protocols could increase the number of donors available for transplantation and protect the lungs from primary graft dysfunction. We hypothesize that perfusate adsorption during ex vivo lung perfusion reconditions the allograft to ischemia-reperfusion injury after lung transplantation. METHODS: Donor pig lungs were preserved for 24 hours at 4°C, followed by 6 hours of ex vivo lung perfusion according to the Toronto protocol. The perfusate was additionally adsorbed through a CytoSorb adsorber (CytoSorbents, Berlin, Germany) in the treatment group, whereas control lungs were perfused according to the standard protocol (n = 5, each). Ex vivo lung perfusion physiology and biochemistry were monitored. Upon completion of ex vivo lung perfusion, a left single lung transplantation was performed. Oxygenation function and lung mechanics were assessed during a 4-hour reperfusion period. The inflammatory response was determined during ex vivo lung perfusion and reperfusion. RESULTS: The cytokine concentrations in the perfusate were markedly lower with the adsorber, resulting in improved ex vivo lung perfusion physiology and biochemistry during the 6-hour perfusion period. Post-transplant dynamic lung compliance was markedly better during the 4-hour reperfusion period in the treatment group. Isolated allograft oxygenation function and dynamic compliance continued to be superior in the adsorber group at the end of reperfusion, accompanied by a markedly decreased local inflammatory response. CONCLUSIONS: Implementation of an additional cytokine adsorber has refined the standard ex vivo lung perfusion protocol. Furthermore, cytokine removal during ex vivo lung perfusion improved immediate post-transplant graft function together with a less intense inflammatory response to reperfusion in pigs. Further studies are warranted to understand the beneficial effects of perfusate adsorption during ex vivo lung perfusion in the clinical setting.

Functional, Metabolic and Morphologic Results of Ex Vivo Donor Lung Perfusion with a Perfluorocarbon-Based Oxygen Carrier Nanoemulsion in a Large Animal Transplantation Model.

BACKGROUND: Ex vivo lung perfusion (EVLP) is a technology that allows the re-evaluation of questionable donor lung before implantation and it has the potential to repair injured donor lungs that are otherwise unsuitable for transplantation. We hypothesized that perfluorocarbon-based oxygen carrier, a novel reconditioning strategy instilled during EVLP would improve graft function. METHODS: We utilized perfluorocarbon-based oxygen carrier (PFCOC) during EVLP to recondition and improve lung graft function in a pig model of EVLP and lung transplantation. Lungs were retrieved and stored for 24 h at 4 °C. EVLP was done for 6 h with or without PFCOC. In the transplantation groups, left lung transplantation was done after EVLP with or without PFCOC. Allograft function was assessed by means of pulmonary gas exchange, lung mechanics and vascular pressures, histology and transmission electron microscopy (TEM). RESULTS: In the EVLP only groups, physiological and biochemical markers during the 6-h perfusion period were comparable. However, perfusate lactate potassium levels were lower and ATP levels were higher in the PFCOC group. Radiologic assessment revealed significantly more lung infiltrates in the controls than in the PFCOC group (p = 0.04). In transplantation groups, perfusate glucose consumption was higher in the control group. Lactate levels were significantly lower in the PFCOC group (p = 0.02). Perfusate flavin mononucleotide (FMN) was significantly higher in the controls (p = 0.008). Post-transplant gas exchange was significantly better during the 4-h reperfusion period in the PFCOC group (p = 0.01). Plasma IL-8 and IL-12 levels were significantly lower in the PFCOC group (p = 0.01, p = 0.03, respectively). ATP lung tissue levels at the end of the transplantation were higher and myeloperoxidase (MPO) levels in lung tissue were lower in the PFCOC group compared to the control group. In the PFCOC group, TEM showed better tissue preservation and cellular viability. CONCLUSION: PFCOC application is safe during EVLP in lungs preserved 24 h at 4 °C. Although this strategy did not significantly affect the EVLP physiology, metabolic markers of the donor quality such as lactate production, glucose consumption, neutrophil infiltration and preservation of mitochondrial function were better in the PFCOC group. Following transplantation, PFCOC resulted in better graft function and TEM showed better tissue preservation, cellular viability and improved gas transport.

Rare indications for a lung transplant. A European Society of Thoracic Surgeons survey.

OBJECTIVES: The European Society of Thoracic Surgeons Lung Transplantation Working Group promoted a survey to evaluate overall survival in a large cohort of patients receiving lung transplants for rare pulmonary diseases. METHODS: We conducted a retrospective multicentre study. The primary end point was overall survival; secondary end points were survival of patients with the most common diagnoses in the context of rare pulmonary diseases and chronic lung allograft dysfunction (CLAD)-free survival. Finally, we analysed risk factors for overall survival and CLAD-free survival. RESULTS: Clinical records of 674 patients were extracted and collected from 13 lung transplant centres; diagnoses included 46 rare pulmonary diseases. Patients were followed for a median of 3.1 years. The median survival after a lung transplant was 8.5 years. The median CLAD-free survival was 8 years. The multivariable analysis for mortality identified CLAD as a strong negative predictor [hazard ratio (HR) 6.73)], whereas induction therapy was a protective factor (HR 0.68). The multivariable analysis for CLAD occurrence identified induction therapy as a protective factor (HR 0.51). When we stratified patients by CLAD occurrence in a Kaplan-Meier plot, the survival curves diverged significantly (log-rank test: P < 0.001). Patients with rare diseases who received transplants had chronic rejection rates similar to those of the general population who received transplants. CONCLUSIONS: We observed that overall survival and CLAD-free survival were excellent. We support the practice of allocating lungs to patients with rare pulmonary diseases because a lung transplant is both effective and ethically acceptable.

Effects of Warm Versus Cold Ischemic Donor Lung Preservation on the Underlying Mechanisms of Injuries During Ischemia and Reperfusion.

BACKGROUND: Ischemia-reperfusion injury related to lung transplantation is a major contributor to early postoperative morbidity and mortality. We hypothesized that donation after cardiac death donor lungs experience warm ischemic conditions that activate different injurious mechanisms compared with donor lungs that undergo prolonged cold ischemic conditions. METHODS: Rat donor lungs were preserved under different cold ischemic times (CIT) (12 hours or 18 hours), or under warm ischemia time (WIT) (3 hours) after cardiac death, followed by single left lung transplantation. Lung function was analyzed during the 2-hour reperfusion period. Microscopic injury, cell death, energy status, and inflammatory responses were assessed. RESULTS: Pulmonary oxygenation function was significantly worse in both 18hCIT and WIT groups, accompanied by higher peak airway pressure, acute lung injury scores, and expression of cell death markers compared with the 12hCIT control group. In lung tissue, reperfusion induced increased expression levels of interleukin (IL)-1α, IL-1ß, IL-6, and chemokines CCL2, CCL3, CXCL1, and CXCL2 in CIT lungs. Notably, these changes were much lower in the WIT group. Additionally, plasma levels of IL-6, IL-18, CCL2, and vascular endothelial growth factor were significantly higher, and adenosine triphosphate levels were significantly reduced in warm versus cold ischemic lungs. CONCLUSIONS: Compared with 12hCIT, posttransplant pathophysiology deteriorated similarly in both 18hCIT and WIT groups. However, tissue adenosine triphosphate levels and inflammatory profiling differed between warm versus cold ischemic donor lungs. These differences should be carefully considered when developing specific therapeutic strategies to reduce ischemia-reperfusion injury in lung transplantation.

Previous lung volume reduction surgery does not negatively affect survival after lung transplantation.

OBJECTIVES: Lung volume reduction surgery (LVRS) and lung transplantation (LTx) are the treatments of choice in selected patients with end-stage emphysema. Recently, the history of LVRS has been questioned due to reduced post-transplant survival. We aim to address this question by reviewing our experience, which is the largest single-centre series of LVRS followed by LTx. METHODS: We reviewed our prospectively recorded database in patients with emphysema undergoing LTx between 1993 and 2014. Preoperative workup and postoperative outcomes were compared according to previous LVRS status. The Kaplan-Meier test was used for survival analysis and compared with a log-rank test. RESULTS: One hundred and seventeen patients (66 men; mean age 56 ± 7 years) underwent LTx during the study period, 52 of whom had previous LVRS (LVRS + LTx). The mean time from LVRS to LTx was 45 ± 31 months. Patients were slightly older and had extensive smoking history in the LVRS + LTx group. Overall, in-hospital mortality was 10%, which did not differ significantly regardless of the history of LVRS (P = 0.8). The median survival for the LTx-only and LVRS + LTx groups was 86 [95% confidence interval (CI) 56-116] and 107 (95% CI 77-137) months, respectively (P = 0.6). CONCLUSIONS: Previous LVRS does not negatively affect short-term and long-term outcomes following LTx in patients with end-stage emphysema. The history of LVRS should not preclude the candidacy for LTx. Considering the limited number of donors available, the LVRS option should be kept in mind for the postponement of LTx in carefully selected patients.

Ex vivo treatment with inhaled N-acetylcysteine in porcine lung transplantation.

BACKGROUND: We have shown the beneficial effects of N-acetylcysteine (NAC) on posttransplant lung function, when both donor and recipient were pretreated intravenously. However, systemic treatment of multiorgan donors may not be clinically relevant. Thus, we hypothesized that ex vivo treatment of donors with nebulized NAC would be adequate to prevent from ischemia-reperfusion injury after lung transplantation. METHODS: Lungs were retrieved from domestic pigs and stored at 4°C for 24 h followed by 2 h of ex vivo lung perfusion (EVLP) to administer 50 mg/kg of NAC via nebulization in the NAC group (n = 6). The control group received nebulized saline (n = 5). Left lungs were transplanted and isolated at 1 h of reperfusion by occluding the right main bronchus and pulmonary artery, followed by 5 h of observation. Physiological data during EVLP and after reperfusion were recorded. Inflammatory response, markers of oxidative stress, and microscopic lung injury were analyzed. RESULTS: There was a trend toward better oxygenation throughout reperfusion period in the treatment group, which was accompanied by inhibited inflammatory response related to reduction in myeloperoxidase activity during EVLP and nuclear factor-κB activation at the end of reperfusion. CONCLUSIONS: Ex vivo treatment of donor lungs with inhaled NAC reduced inflammatory response via its antioxidant activity in experimental porcine lung transplantation.

Ex vivo administration of trimetazidine improves post-transplant lung function in pig model.

OBJECTIVES: Ex vivo lung perfusion (EVLP) is not only used to assess marginal donor lungs but is also used as a platform to deliver therapeutic agents outside the body. We previously showed the beneficial effects of trimetazidine (TMZ) on ischaemia reperfusion (IR) injury in a rat model. This study evaluated the effects of TMZ in a pig EVLP transplant model. METHODS: Pig lungs were retrieved and stored for 24 h at 4°C, followed by 4 h of EVLP. Allografts were randomly allocated to 2 groups ( n = 5 each). TMZ (5 mg/kg) was added to the prime solution prior to EVLP. After EVLP, left lungs were transplanted and recipients were observed for 4 h. Allograft gas exchange function and lung mechanics were recorded hourly throughout reperfusion. Microscopic lung injury and inflammatory and biochemical parameters were assessed. RESULTS: There was a trend towards better oxygenation during EVLP in the TMZ group ( P = 0.06). After transplantation, pulmonary gas exchange was significantly better during the 4-h reperfusion period and after isolation of the allografts for 10 min ( P < 0.05). Tissue thiobarbituric acid levels, myeloperoxidase activity and protein concentrations in bronchoalveolar lavage samples were significantly lower in the TMZ group at the end of EVLP ( P < 0.05). CONCLUSIONS: Ex vivo treatment of donor lungs with TMZ significantly improved immediate post-transplant lung function. Further studies are warranted to understand the effect of this strategy on long-term lung function.

Cytokine filtration modulates pulmonary metabolism and edema formation during ex vivo lung perfusion.

BACKGROUND: Ex vivo lung perfusion (EVLP) has improved the process of donor lung management. Cytokine accumulation during EVLP has been shown to correlate with worse outcome after lung transplantation. Our objective in this study was to test the safety and efficacy of cytokine filtration during EVLP in a large animal model. METHODS: Pig donor lungs were preserved for 24 hours at 4°C, followed by 12 hours of EVLP, according to the Toronto protocol. The perfusate was continuously run through an absorbent device (CytoSorb) via a veno-venous shunt from the reservoir in the filter group. EVLP was performed according to the standard protocol in the control group (n = 5 each). EVLP physiology, lung X-ray, perfusate biochemistry, inflammatory response and microscopic injury were assessed. RESULTS: Cytokine filtration significantly improved airway pressure and dynamic compliance during the 12-hour perfusion period. Lung X-rays acquired at the end of perfusion showed increased consolidation in the control group. Electrolyte imbalance, determined by increased hydrogen, potassium and calcium ion concentrations in the perfusate, was markedly worsened in the control group. Glucose consumption and lactate production were markedly reduced, along with the lactate/pyruvate ratio in the filter group. Cytokine expression profile, tissue myeloperoxidase activity and microscopic lung injury were significantly reduced in the filter group. CONCLUSIONS: Continuous perfusate filtration through sorbent beads is effective and safe during prolonged EVLP. Cytokine removal decreased the development of pulmonary edema and electrolyte imbalance through the suppression of anaerobic glycolysis and neutrophil activation in this setting. Further studies are needed to test the beneficial effect of cytokine filtration on post-transplant lung function.

Lung Lavage and Surfactant Replacement During Ex Vivo Lung Perfusion for Treatment of Gastric Acid Aspiration-Induced Donor Lung Injury.

BACKGROUND: Ex vivo lung perfusion (EVLP) provides opportunities to treat injured donor lungs before transplantation. We investigated whether lung lavage, to eliminate inflammatory inhibitory components, followed by exogenous surfactant replacement, could aid lung recovery and improve post-transplant lung function after gastric aspiration injury. METHODS: Gastric acid aspiration was induced in donor pigs, which were ventilated for 6 hours to develop lung injury. After retrieval and 10 hours of cold preservation, EVLP was performed for 6 hours. The lungs were randomly divided into 4 groups (n = 5, each): (1) no treatment (control), (2) lung lavage, (3) surfactant administration, and (4) lung lavage, followed by surfactant administration. After another 2-hour period of cold preservation, the left lung was transplanted and reperfused for 4 hours. RESULTS: Physiologic lung function significantly improved after surfactant administration during EVLP. The EVLP perfusate from the lavage + surfactant group showed significantly lower levels of interleukin (IL)-1ß, IL-6, IL-8, and secretory phospholipase A2. Total phosphatidylcholine was increased, and minimum surface tension was recovered to normal levels (≤5 mN/m) in the bronchioalveolar fluid after surfactant administration. Lysophosphatidylcholine in bronchioalveolar fluid was significantly lower in the lavage + surfactant group than in the surfactant group. Post-transplant lung function was significantly better in the lavage + surfactant group compared with all other groups. CONCLUSIONS: Lung lavage, followed by surfactant replacement during EVLP, reduced inflammatory mediators and prevented hydrolysis of phosphatidylcholine, which contributed to the superior post-transplant function in donor lungs with aspiration injury.

Mesenchymal stem cell treatment is associated with decreased perfusate concentration of interleukin-8 during ex vivo perfusion of donor lungs after 18-hour preservation.

BACKGROUND: Ex vivo lung perfusion (EVLP) presents a unique therapeutic opportunity to administer mesenchymal stromal cells (MSCs) to lung grafts before transplantation. We sought to determine the optimal route and dose of viable human umbilical cord-derived MSCs to be delivered into ex vivo-perfused damaged swine lungs, and to measure their effect on concentration of growth factors and inflammatory mediators. METHODS: Pig lungs were conventionally retrieved, cold preserved for 18 hours, and perfused normothermically ex vivo for 12 hours. Physiologic data were recorded. No cells were administered to a control group of animals (n = 5). To examine the routes of administration, lungs were administered 50 × 106 MSCs endobronchially (n = 3) or via the pulmonary artery (n = 3). To determine the doses, a dose-escalation study was performed wherein lungs were administered 50 × 106 (n = 3), 150 × 106 (n = 5) and 300 × 106 (n = 3) MSCs via the pulmonary artery. Concentrations of human growth factors and pig cytokines were measured in lung biopsies and perfusate. RESULTS: Intravascular administration of 50 × 106 MSCs was associated with significant and sustained retention of MSCs in lung parenchyma, whereas intrabronchial administration was not. Intravascular administration of 150 × 106 MSCs was the optimal tolerated dose and was associated with increased concentrations of human vascular endothelial growth factor (VEGF) in lung biopsies and decreased concentrations of pig interleukin-8 (IL-8) in the perfusate during 12 hours of EVLP. CONCLUSIONS: Intravascular delivery of 150 × 106 MSCs showed preferred outcome compared with intrabronchial delivery to damaged lungs perfused ex vivo. The method was well tolerated and associated with an increased concentration of human VEGF in the lung tissue and a decreased concentration of pig IL-8 in the perfusate.

Importance of left atrial pressure during ex vivo lung perfusion.

BACKGROUND: Ex vivo lung perfusion (EVLP) allows for the evaluation and treatment of donor lungs before transplant. Different EVLP strategies have been described using either an open left atrium (LA) (pressure of 0 mm Hg) or closed LA (pressure of 5 mm Hg). We hypothesized that maintaining a physiologic positive LA pressure during EVLP is protective to the lung. METHODS: Pig lungs were flushed with Perfadex, retrieved and stored at 4°C for 4 hours [short cold ischemic time (CIT), n = 10] or 18 hours (prolonged CIT, n = 8). Subsequently, lungs underwent normothermic EVLP for 12 hours using either an open or closed LA technique. A linear mixed effect model was used to compare functional parameters between the 2 groups. RESULTS: After short CIT, 12-hour EVLP could not be completed in 4 of 5 open atrium cases due to significant pulmonary edema. Lung injury was evident in this group after 7 hours of EVLP, demonstrating an increase in pulmonary vascular resistance (p < 0.001) and peak inspiratory pressure (p = 0.001), and a decrease in lung compliance (p < 0.001) and perfusate oxygenation (p = 0.04). In contrast, in the closed atrium group, all lungs completed 12 hours of EVLP with stable functional parameters. At the end of the experiment, the wet/dry ratio (p = 0.015) and lung edema score (p = 0.02) were significantly worse in the open LA group compared with the closed LA EVLP group. Similar findings were observed in the prolonged CIT group. CONCLUSION: The use of a closed atrial technique to create a controlled positive LA during EVLP leads to significantly less edema and superior lung physiology.

Human α1-antitrypsin improves early post-transplant lung function: Pre-clinical studies in a pig lung transplant model.

BACKGROUND: The translation of novel drugs in lung transplantation is challenged by different physiologic conditions between small animals and humans. Large-animal models provide important pre-clinical evidence and the next step that best informs clinical trials. In the present study, we used a pig lung transplant model to determine whether human α1-antitrypsin (A1AT), a medication shown to prevent pulmonary ischemia-reperfusion injury in rats, could attenuate reperfusion injury after prolonged hypothermic preservation in a large-animal lung transplant model. METHODS: Donor lungs were preserved for 24 hours at 4°C, followed by lung transplantation. In a randomized and blinded fashion, intravenous A1AT (240 mg/kg; n = 5) or human albumin (n = 5) was administered to the recipient before reperfusion. Allograft gas exchange function and lung mechanics were monitored during a 4-hour reperfusion period. Microscopic lung injury, inflammatory response, coagulation activity, and cell death were assessed. RESULTS: Pulmonary gas exchange was significantly better during the 4-hour reperfusion period in the A1AT group. Treatment with A1AT improved static pulmonary compliance and significantly reduced pulmonary edema and lung permeability. A1AT treatment inhibited inflammatory mediators in the circulation, with reduced activation of nuclear factor-κB and inflammasome, reduced formation of thrombin-antithrombin complex in plasma, and reduced apoptosis in the allografts. CONCLUSIONS: Administration of human A1AT before reperfusion in recipients improved immediate post-transplant lung function in pigs. A large-animal survival model should be considered to support further advancement toward a clinical trial of A1AT to prevent primary graft dysfunction in lung transplantation.

Annexin V homodimer protects against ischemia reperfusion-induced acute lung injury in lung transplantation.

OBJECTIVE: We hypothesized that administration of a homodimer of recombinant annexin V, diannexin, could shield phosphatidylserine on the endothelium, and inhibit leukocyte and platelet adhesion, thereby potentially reducing ischemia reperfusion injury (IRI) in lung transplantation. This hypothesis was tested using a rat syngeneic single left-lung transplant model. METHODS: Rats were randomly assigned to receive diannexin (DN group; n = 10) or normal saline (control group; n = 10). Diannexin (1000 µg/kg) was administered to the donor lung in the pulmonary flush solution, and to the recipient intravenously, 5 minutes after initiation of reperfusion. Grafts were reperfused for 2 hours. RESULTS: The transplanted grafts in the DN group performed significantly better in gas exchange with higher partial pressure of oxygen (control group: 179 ± 121 vs DN group: 330 ± 54 mm Hg; P = .007) and lower partial pressure of carbon dioxide (control: 55.1 ± 26 vs DN: 34.2 ± 11 mm Hg; P = .04), as well as lower peak airway pressure (control: 20.5 ± 8.5 vs DN: 12.0 ± 7.9 cm H2O; P = .035) after 2 hours of reperfusion. Wet-to-dry lung weight ratio (P = .054), and alveolar fibrin deposition score (P = .04), were reduced in the DN group. Caspase-cleaved cytokeratin 18 in plasma (a marker of epithelial apoptosis) was significantly reduced in the DN group (P = .013). Furthermore, gene-expression levels of proinflammatory cytokines in the transplanted graft, including interleukin-6 (P = .04) and macrophage inflammatory protein 2 (P = .03) were significantly decreased in the DN group. CONCLUSIONS: A homodimer of recombinant annexin V reduced ischemia reperfusion injury in a lung transplant animal model, by reducing cell death and tissue inflammation.

Extension of donor lung preservation with hypothermic storage after normothermic ex vivo lung perfusion.

BACKGROUND: Ex vivo lung perfusion (EVLP) allows normothermic evaluation and treatment of donor lungs not currently acceptable for transplant and improves organ use. Donor lungs undergo a period of cold preservation before (cold ischemic time [CIT]-1) and after (CIT-2) EVLP. We investigated the effect of an extended CIT-2 on lung function after transplantation. METHODS: Explanted pig lungs, preserved in low-potassium dextran flush (Perfadex) at 4°C for 10 hours, were subjected to 6 hours of EVLP. They were subsequently allocated to 2 groups: short CIT-2 (CIT-2 = 2 hours; n = 5), and long CIT-2 (CIT-2 = 10 hours; n = 5). In a control group (n = 6), explanted lungs were placed in cold static preservation for 24 hours without EVLP. After the total preservation period, the left lung was transplanted in all groups. RESULTS: After 4 hours of reperfusion, oxygenation function, acute lung injury score, inflammatory markers, and cell death pathway markers were similar between short and long CIT-2 groups. Both EVLP groups fared significantly better than the control group in oxygenation function (p < 0.05). CONCLUSIONS: The intervention of EVLP improved lung function after transplantation, and this was not affected by a prolonged cold static preservation time after EVLP. These results provide the basis for a practical prolonged lung preservation strategy using a combination of cold and warm preservation techniques, which may improve lung transplantation logistics and outcomes.

Modified in vivo lung perfusion allows for prolonged perfusion without acute lung injury.

OBJECTIVES: In vivo lung perfusion (IVLP) is an emergent strategy to treat lung metastases because it allows localized delivery of chemotherapy with minimal systemic exposure. Previously, short-term (± 30 minutes) IVLP resulted in variable efficacy and significant lung toxicity. We hypothesize that a modified IVLP strategy derived from an ex vivo lung perfusion technique could minimize lung injury. Our objective was to demonstrate the feasibility and safety of a modified prolonged (4 hours) IVLP. METHODS: Six Yorkshire pigs were used for the experiments. A thoracotomy was performed, the left pulmonary artery and pulmonary veins were cannulated, and the left lung was isolated in situ. IVLP was performed at normothermia for 4 hours using Steen Solution (XVIVO Perfusion, Göteburg, Sweden) as perfusate. The flow rate was 16% of estimated cardiac output and left atrial pressure was maintained between 3 and 5 mm Hg. Perfusate was deoxygenated and supplied with CO2 to physiologic levels before entering the lungs. A protective mode of ventilation was used. After IVLP, the left lung was allowed to reperfuse for additional 4 hours. Airway dynamics, gas exchange, and pulmonary vascular resistance were used to assess left lung physiology. Histologic signs of lung injury were assessed before and after IVLP, and 4 hours after reperfusion. RESULTS: Lung function parameters were stable throughout the 4-hour IVLP and during reperfusion. No significant histologic evidence of acute lung injury was observed. CONCLUSIONS: Four hours of IVLP is feasible without adding significant lung injury. Prolonged perfusion time and a protective protocol might provide safer and more efficacious treatment of pulmonary metastases.

The experimental use of N-butyl cyanoacrylate tissue adhesive in pulmonary wedge resections.

BACKGROUND: In this experimental study, the effectiveness of N-butyl cyanoacrylate tissue adhesive on preventing air leakage after pulmonary wedge resection was observed. METHODS: Twenty pairs of sheep lungs were used. Before initiating the study, the sheep lungs were ventilated to identify any air leakage from the parenchyma. On positive results, those sheep lungs were then excluded from the study. Wedge resection was performed on the right and left lower lobes of sheep lungs by clamping the edges forming a triangle of 5 cm × 5 cm × 5 cm. One side of parenchyma was sutured by 3/0 vicryl (Group A) while the other side of parenchyma was sealed by N-butyl cyanoacrylate (Group B). After waiting for 5 min for N-butyl cyanoacrylate to dry, the sheep lungs were intubated by 6F endotracheal tubes. The lungs were soaked in a bath tub filled with 10 cm deep water and inflated by 40 mmHg pressure to record any air leakage from the parenchyma partially sutured by vicryl and sealed by N-butyl cyanoacrylate. RESULTS: Air leakages were observed on the parenchyma surfaces of group of lungs (100%) sutured by vicryl (minimal 30%, mild 50% or massive 20% levels), while only on four of (20%) the other group of lungs sealed by N-butyl cyanoacrylate, minimal air leakage was observed on the parenchymal surface. There was an extremely significant difference between Group A and Group B in terms of the development of air leakage (p=000). CONCLUSION: We consider that, N-butyl cyanoacrylate could be used effectively and safely to prevent air leakage from the pulmonary wedge resection surface.

False-positivity of mediastinal lymph nodes has negative effect on survival in potentially resectable non-small cell lung cancer.

OBJECTIVES: It has been shown that increased metabolic activity of primary tumour has a negative effect on survival in non-small cell lung cancer (NSCLC) staged with positron emission tomography integrated computed tomography (PET/CT). We hypothesized that an increased metabolic activity of mediastinal lymph nodes would have worse survival even if it is false. METHODS: Three hundred and twenty-eight consecutive patients with NSCLC histology were imaged with PET/CT within 90 days of surgery between September 2005 and March 2009. Patients who had neoadjuvant chemotherapy (n = 22), patients with prior history of NSCLC (n = 9) or other malignancies within 5 years (n = 11) were excluded from the study. Patients with negative mediastinoscopy underwent resection. Pathological results were revised according to the seventh tumor-node-metastasis staging system. Kaplan-Meier test was used for survival. Log-rank and Cox analyses were used for comparisons. RESULTS: A total of 286 patients (262 male; mean age: 58.5 years) were evaluated. There were 22 (6.7%) operative deaths and none of the patients were lost to follow-up. The median follow-up in the remaining 264 patients was 26 months (range, 2-61 months). Tumour size, nodal spread and stage were all strongly associated with survival from NSCLC (P < 0.001). There were 63 true-positive, 65 false-positive (FP), 152 true-negative (TN) and six false-negative findings on mediastinal staging after PET/CT. The maximum standardized uptake value of primary tumour was significantly higher in FP patients than in TN patients (P = 0.012). After excluding pN2-positive patients, TN patients had better survival than FP patients (P = 0.006). Multivariate analysis showed that false-positivity of mediastinal lymph nodes was independently associated with worse survival (hazard ratio = 0.63; P = 0.02). There were 146 patients with pT1-4, pN0 treated with R0 surgical resection. Disease-free survival and overall survival were also significantly better for TN patients in completely resected group (P = 0.009 versus 0.016). CONCLUSIONS: We have shown that false-positivity of mediastinal lymph nodes had yielded worse survival in surgically staged or resected NSCLC patients staged with PET/CT. This result may help to allocate patients with potentially poor prognosis for considered additional therapy.

Is there any maximum standardized uptake value variation among positron emission tomography scanners for mediastinal staging in non-small cell lung cancer?

The maximum standardized uptake value (SUV(max)) varies among positron emission tomography-integrated computed tomography (PET/CT) centers in the staging of non-small cell lung cancer. We evaluated the ratio of the optimum SUV(max) cut-off for the lymph nodes to the median SUV(max) of the primary tumor (ratioSUV(max)) to determine SUV(max) variations between PET/CT scanners. The previously described PET predictive ratio (PPR) was also evaluated. PET/CT and mediastinoscopy and/or thoracotomy were performed on 337 consecutive patients between September 2005 and March 2009. Thirty-six patients were excluded from the study. The pathological results were correlated with the PET/CT findings. Histopathological examination was performed on 1136 N2 lymph nodes using 10 different PET/CT centers. The majority of patients (group A: 240) used the same PET/CT scanner at four different centers. Others patients were categorized as group B. The ratioSUV(max) for groups A and B was 0.18 and 0.22, respectively. The same ratio for centers 1, 2, 3 and 4 was 0.2, 0.21, 0.21, and 0.23, respectively. The optimal cut-off value of the PPR to predict mediastinal lymph node pathology for malignancy was 0.49 (likelihood ratio +2.02; sensitivity 70%, specificity 65%). We conclude that the ratioSUV(max) was similar for different scanners. Thus, SUV(max) is a valuable cut-off for comparing-centers.