Off-pump lung re-transplantation avoiding clamshell thoracotomy is feasible and safe: a single-center experience.

Background: Lung re-transplantation (re-LTx) is the only therapeutic option for selected patients with advanced allograft dysfunction. This study aims to describe our center's experience to illustrate the feasibility and safety of off-pump re-LTx avoiding clamshell incision. Methods: We performed a retrospective analysis of 42 patients who underwent bilateral re-LTx between 2007 and 2021. Patients were classified according to their surgical approach and extracorporeal life support (ECLS)-use. Demographics, surgical technique, and short- and long-term outcomes were compared between groups. Continuous data were examined with an independent-sample t-test or non-parametric test. Pearson's chi-squared and Fisher's exact were used to analyze categorical data. Results: Twenty-six patients (61.9%) underwent re-LTx by anterior thoracotomy without ECLS. Compared to the more invasive approach (thoracotomy with ECLS and clamshell with/without ECLS, n=16, 38.1%), clamshell-avoiding off-pump re-LTx patients had a shorter operative time (471.6±111.2 vs. 704.0±273.4 min, P=0.010) and less frequent grade 3 primary graft dysfunction (PGD-3) at 72 h (7.7% vs. 37.5%, P=0.038). No significant difference was found in PGD-3 incidence within 72 h, mechanical ventilation, intensive care unit (ICU) and hospital stay, and the incidence of reoperation within 90 days between groups (P>0.05). In the long-term, the clamshell-avoiding and off-pump approach resulted in similar 1- and 5-year patient survival vs. the more invasive approach. Conclusions: Our experience shows that clamshell-avoiding off-pump re-LTx is feasible and safe in selected patients on a case-by-case evaluation.

Argon and xenon ventilation during prolonged ex vivo lung perfusion.

BACKGROUND: Evidence supports the use of ex vivo lung perfusion (EVLP) as a platform for active reconditioning before transplantation to increase the potential donor pool and to reduce the incidence of primary graft dysfunction. A promising reconditioning strategy is the administration of inhaled noble gases based on their organoprotective effects. Our aim was to validate a porcine warm ischemic lung injury model and investigate postconditioning with argon (Ar) or xenon (Xe) during prolonged EVLP. METHODS: Domestic pigs were divided in four groups (n = 5 per group). In the negative control group, lungs were flushed immediately. In the positive control (PC) and treatment (Ar, Xe) groups, lungs were flushed after a warm ischemic interval of 2-h in situ. All grafts were evaluated and treated during normothermic EVLP for 6 h. In the control groups, lungs were ventilated with 70% N2/30% O2 and in the treatment groups with 70% Ar/30% O2 or 70% Xe/30% O2, respectively. Outcome parameters were physiological variables (pulmonary vascular resistance, peak airway pressures, and PaO2/FiO2), histology, wet-to-dry weight ratio, bronchoalveolar lavage, and computed tomography scan. RESULTS: A significant difference between negative control and PC for pulmonary vascular resistance, peak airway pressures, PaO2/FiO2, wet-to-dry weight ratio, histology, and computed tomography-imaging was observed. No significant differences between the injury group (PC) and the treatment groups (Ar, Xe) were found. CONCLUSIONS: We validated a reproducible prolonged 6-h EVLP model with 2 h of warm ischemia and described the physiological changes over time. In this model, ventilation during EVLP with Ar or Xe administered postinjury did not improve graft function.

Retrograde flush is more protective than heparin in the uncontrolled donation after circulatory death lung donor.

BACKGROUND: Formation of microthrombi after circulatory arrest is a concern for the development of reperfusion injury in lung recipients from donation after circulatory death (DCD) donors. In this isolated lung reperfusion study, we compared the effect of postmortem heparinization with preharvest retrograde pulmonary flush or both. METHODS: Domestic pigs (n = 6/group) were sacrificed by ventricular fibrillation and left at room temperature for 1 h. This was followed by 2.5 h of topical cooling. In control group [C], no heparin and no pulmonary flush were administered. In group [R], lungs were flushed with Perfadex in a retrograde way before explantation. In group [H], heparin (300 IU/kg) was administered 10 min after cardiac arrest followed by closed chest massage for 2 min. In the combined group, animals were heparinized and the lungs were explanted after retrograde flush [HR]. The left lung was assessed for 60 min in an ex vivo reperfusion model. RESULTS: Pulmonary vascular resistance at 50 and 55 min was significantly lower in [R] and [HR] groups compared with [C] and [H] groups (P < 0.01 and P < 0.001) and at 60 min in [R], [H], and [HR] groups compared with [C] group (P < 0.001). Oxygenation, compliance, and plateau airway pressure were more stable in [R] and [HR] groups. Plateau airway pressure was significantly lower in [R] group compared with the [H] group at 60 min (P < 0.05). No significant differences in wet-dry weight ratio were observed between the groups. CONCLUSIONS: This study suggests that preharvest retrograde flush is more protective than postmortem heparinization to prevent reperfusion injury in lungs recovered from donation after circulatory death donors.

Evaluating lung injury at increasing time intervals in a murine brain death model.

INTRODUCTION: Only 15%-25% of brain death (BD) donors match the ideal donor criteria for lung transplantation. Lung injury may evolve in the hours after onset of brain death, but the evolution over time has not been well studied in lung. The aim of this study was to evaluate lung injury at different time points after BD using a murine model. MATERIALS AND METHODS: Male C57BL6/J mice (8-10 wk) were anesthetized, tracheotomized, and mechanically ventilated. Mice were randomly assigned to six groups (n=8/group): 1 h, 3 h, and 6 h sham ([SH1], [SH3], [SH6]) and 1 h, 3 h, and 6 h brain death ([BD1], [BD3], [BD6]). BD was gradually induced by a subdural balloon catheter. Heart rate and mean arterial pressure were continuously monitored. At the end of the experiment, bronchoalveolar lavage was performed and the left lung was excised for histopathologic analysis. RESULTS: The Cushing reflex was characterized by a rapid increase in heart rate and mean arterial pressure after balloon inflation in BD animals. An increase in percentage of neutrophils was seen with a longer follow-up period (P<0.05). Interleukin 6 and interleukin 10 levels in bronchoalveolar lavage progressively increased with longer time intervals after BD ([BD1] versus [BD6]; P<0.01). Histologic signs of lung injury (congestion, hemorrhage, and neutrophilic influx) were more pronounced in [BD3] and [BD6] compared with the other groups; however, this difference did not reach statistical significance. CONCLUSION: Three hours after brain death, significant signs of inflammation and lung injury were seen compared with sham-operated animals. This murine BD model gives us opportunities for further mechanistic studies regarding treatment of BD-related donor lung injury.

Medium-term outcome after lung transplantation is comparable between brain-dead and cardiac-dead donors.

BACKGROUND: Donation after cardiac death (DCD) to overcome the donor organ shortage is now moving into the clinical setting, but the medium-term outcome after DCD lung transplantation (LTx) remains largely unknown. METHODS: In this retrospective study, DCD LTx recipients (n = 21) were compared with a cohort of donation-after-brain-death (DBD) LTx recipients (n = 154) transplanted between February 2007 and July 2010. Immediate (post)operative outcome was evaluated by assessing need for peri-operative extracorporeal membrane oxygenation (ECMO), time to extubation, hospital discharge and primary graft dysfunction (PGD) within the first 48 hours. Survival, incidence of bronchiolitis obliterans syndrome (BOS), acute rejection (AR) and inflammatory markers in blood and in bronchoalveolar lavage (BAL) were assessed and compared over a median follow-up of 327 days for DCD and 531 days for DBD, showing no statistically significant difference (NS). RESULTS: There were no differences between groups with regard to patient characteristics except for a higher number of patients transplanted for obliterative bronchiolitis in the DCD group (4 of 21 vs 7 of 154; p < 0.05). In the DCD group, 2 of 21 patients died, vs 23 of 154 patients in the DBD group (NS). Actuarial survival rates at 6 months, 1 year and 3 years are 95%, 95% and 71% for the DCD group and 96%, 91% and 75% for the DBD group (NS). Three patients (14%) in the DCD group developed BOS vs 15 patients (10%) in the DBD group (NS). Survival and freedom from BOS were not different between the groups. AR, inflammatory markers and immediate (post)operative outcome also did not differ. CONCLUSIONS: In our experience, both early- and medium-term outcome in DCD lung recipients is comparable to that of DBD lung recipients. Use of lungs recovered from controlled donors after cardiac death is a safe option for expansion of the donor pool.

Task-independent metrics to assess the data quality of medical registries using the European Society of Thoracic Surgeons (ESTS) Database.

OBJECTIVE: The quality of data collected into a database is of paramount importance in every analysis. No standardized methods are available to quantify the quality of data in medical registries. Expanding the work done in other fields, we aimed at developing a methodological approach to measure the quality of a thoracic surgical database, by using the European Society of Thoracic Surgeons (ESTS) Database. METHODS: A selection of anonymized data collected in the ESTS Database from 2007 to 2009 was tested using appropriate data quality metrics: completeness, correctness, consistency and believability. Particularly, the believability value is obtained as a result of a min-max operation based on the evaluation of completeness, correctness and consistency. Completeness measures the number of missing values in each checked column of the database, and it is calculated as number of variables registered/number of variables expected. Correctness reflects the number of data units in error referring to a set of clearly defined criteria (number of correct data/number of all data counted) and consistency is calculated by verifying the number of data in conflict in the same recorded patient (number of consistent checks/total number of checks). The threshold selected to indicate good quality was 0.8. RESULTS: A total of 49363 values were reviewed to obtain the quality indicators. The results of the data quality assessment for the analyzed section of the ESTS Database are all above the predefined threshold: completeness is 0.85, correctness 0.99 and consistency 0.98. The believability score of data in the database is 0.85. CONCLUSIONS: We were able to apply task-independent metrics to measure the quality within the ESTS Database. This study may represent a template to be applied in the medical/surgical field to test the quality of data in clinical registries. Only registries with a high quality of data can be reliably used for scientific, managerial and credentialing purposes.

A porcine model of acute lung injury by instillation of gastric fluid.

BACKGROUND: About 15% of donor lungs are declined because of aspiration contributing to current organ shortage. The aim was to develop a porcine lung injury model by gastric juice (GJ) instillation to study different pretransplant treatment strategies. MATERIALS AND METHODS: Pigs (n = 6/group) were anesthetized and monitored. At T0 bronchoalveolar lavage (BAL) was performed followed by instillation of 4 mL/kg GJ or saline solution (SAL). Hemodynamics, aerodynamics and oxygenation were recorded for two hours. Serum samples were collected. At T120 a second BAL was performed. CT scans of explanted, inflated lungs were taken, tissue samples were collected and wet/dry weight ratio (W/D) was calculated. Pepsin and bile acids were measured in BAL. IL-8, CRP and MMP-9 were measured in serum and in BAL. RESULT: Oxygenation and lung compliance was lower in [GJ] versus [SAL] (P < 0.01 and P < 0.001, respectively). More consolidation areas were noticed on CT in GJ versus SAL (P < 0.01). Hemorrhage, edema and neutrophil inflammation were seen on histology in [GJ] (P < 0.01, P < 0.001, P < 0.001, respectively). BAL neutrophils, pepsin, bile acids, and IL-8 (P < 0.05) increased in [GJ]. W/D was higher in [GJ] versus SAL (P < 0.001). CONCLUSION: Instillation of GJ in pig lungs caused acute lung injury with impaired oxygenation and increased inflammation in BAL, on histology, and on imaging. This model holds promise to assess the efficacy of a broad range of treatment strategies including ex vivo lung perfusion (EVLP).

The mode of death in the non-heart-beating donor has an impact on lung graft quality.

OBJECTIVE: We hypothesised that the agonal phase prior to cardiac death may negatively influence the quality of the pulmonary graft recovered from non-heart-beating donors (NHBDs). Different modes of death were compared in an experimental model. METHODS: Non-heparinised pigs were divided into three groups (n=6 per group). Animals in group I [FIB] were sacrificed by ventricular fibrillation resulting in immediate circulatory arrest. In group II [EXS], animals were exsanguinated (45+/-11 min). In group III [HYP], hypoxic cardiac arrest (13+/-3 min) was induced by disconnecting the animal from the ventilator. Blood samples were taken pre-mortem in HYP and EXS for measurement of catecholamine levels. After 1 h of in situ warm ischaemia, unflushed lungs were explanted and stored for 3 h (4 degrees C). Left lung performance was then tested during 60 min in our ex vivo reperfusion model. Total protein concentration in bronchial lavage fluid was measured at the end of reperfusion. RESULTS: Pre-mortem noradrenalin (mcg l(-1)) concentration (baseline: 0.03+/-0) increased to a higher level in HYP (50+/-8) vs EXS (15+/-3); p=0.0074. PO(2) (mmHg) at 60 min of reperfusion was significantly worse in HYP compared to FIB (445+/-64 vs 621+/-25; p<0.05), but not to EXS (563+/-51). Pulmonary vascular resistance (dynes s cm(-5)) was initially higher in EXS (p<0.001) and HYP (NS) vs FIB (15824+/-5052 and 8557+/-4933 vs 1482+/-61, respectively) but normalised thereafter. Wet-to-dry weight ratio was higher in HYP compared to FIB (5.2+/-0.3 vs 4.7+/-0.2, p=0.041), but not to EXS (4.9+/-0.2). Total protein (g l(-1)) concentration was higher, although not significant in HYP and EXS vs FIB (18+/-6 and 13+/-4 vs 4.5+/-1.3, respectively). CONCLUSION: Pre-mortem agonal phase in the NHBD induces a sympathetic storm leading to capillary leak with pulmonary oedema and reduced oxygenation upon reperfusion. Graft quality appears inferior in NHBD lungs when recovered in controlled (HYP) vs uncontrolled (EXS and FIB) setting.

Obliterative bronchiolitis following lung transplantation: from old to new concepts?

Lung transplantation has come of age and is now considered a valid treatment for selected patients with end-stage lung disease. In recent years, survival rates have much improved, although the development of chronic rejection, characterized by a progressive and irreversible decline in FEV(1), which is clinically defined as bronchiolitis obliterans syndrome (BOS) remains the major obstacle to long-term survival. Extensive research efforts with special emphasis on innate immunity have recently led to new insights with the identification of at least two different phenotypes: on the one hand there is an azithromycin-responsive phenotype (the so-called neutrophilic reversible allograft/airways dysfunction (NRAD), on the other hand there is an azithromycin-unresponsive phenotype (the fibroproliferative form of BOS or classical obliterative bronchiolitis). The present review intends to give the scientific evidence for these two subtypes, and to clarify the role of azithromycin in the treatment of BOS.

Retrograde flush following warm ischemia in the non-heart-beating donor results in superior graft performance at reperfusion.

BACKGROUND: The use of non-heart-beating donors (NHBD) has been propagated as an alternative to overcome the scarcity of pulmonary grafts. The presence of postmortem thrombi, however, is a concern for the development of primary graft dysfunction. In this isolated lung reperfusion study, we looked at the need and the best route of preharvest pulmonary flush. METHODS: Domestic pigs were sacrificed by ventricular fibrillation and divided in 3 groups (n = 6 per group). After 1 h of in situ warm ischemia, lungs in group I were retrieved unflushed (NF). In group II, lungs were explanted after an anterograde flush (AF) through the pulmonary artery. Finally, in group III, lungs were explanted after a retrograde flush (RF) via the left atrium. After 3 h of cold storage, the left lung was assessed for 60 min in our ex vivo reperfusion model. Wet-to-dry weight ratio (W/D) was calculated after reperfusion. RESULTS: Pulmonary vascular resistance (dynes x sec x cm(-5)) was 1145 +/- 56 (RF) versus 1560 +/- 123 (AF) and 1435 +/- 95 (NF) at 60 min of reperfusion (P < 0.05). Oxygenation and compliance were higher and plateau airway pressure was lower in RF versus AF and NF, although the difference did not reach statistical significance. No differences in W/D were observed between groups after reperfusion. Histological examination revealed fewer microthrombi in the left lung in RF compared with AF and NF. CONCLUSION: RF of lungs from NHBD improves graft function by elimination of microthrombi from the pulmonary vasculature, resulting in lower pulmonary vascular resistance upon reperfusion.

Azithromycin reduces airway inflammation in a murine model of lung ischaemia reperfusion injury.

Clinical studies revealed that azithromycin reduces airway neutrophilia during chronic rejection after lung transplantation. Our aim was to investigate the possible effect of azithromycin on ischaemia-reperfusion injury. Azithromycin or water was administered to mice every other day during 2 weeks (n = 6/group). On the 14th day, the left lung was clamped to induce ischaemia (90 min). In two additional groups, animals underwent the same protocol, followed by 4 h of reperfusion. Two control groups were included with thoracotomy only. Inflammatory parameters and oxidative stress were measured in broncho-alveolar lavage of the left lung. Leukocytes, lymphocytes, neutrophils, 8-isoprostane and IL-1beta levels after ischaemia and reperfusion were significantly reduced in mice treated with azithromycin. There was a trend towards lower IL-6 and KC levels. A significant correlation was seen between 8-isoprostanes and neutrophils (Pearson r = 0.72; P = 0.0086), IL-6 (Pearson r = 0.84; P = 0.0006), KC (Pearson r = 0.88; P = 0.0002) and IL-1beta (Pearson r = 0.62; P = 0.0326). We conclude (i) that azithromycin reduces inflammation and oxidative stress in our IRI model, and (ii) that oxidative stress is correlated with the number of neutrophils and IL-6, KC and IL-1beta levels after ischaemia and reperfusion. Azithromycin should be further investigated as a novel drug to prevent lung ischaemia-reperfusion injury.

N-acetyl cysteine attenuates the inflammatory response in warm ischemic pig lungs.

BACKGROUND: Lungs donated after cardiac death (DCD) may significantly reduce current organ shortage. However, the warm ischemic period following circulatory arrest may enhance ischemia-reperfusion injury (IRI). We investigated the possible therapeutic effect of N-acetyl cysteine (NAC), a potent anti-oxidative agent on IRI in a porcine ex vivo lung reperfusion model. MATERIALS AND METHODS: NAC (50 mg/kg) was nebulized to pigs (n = 6/group) prior to sacrifice (NAC-DCD). In DCD-NAC, animals received NAC 15 min after death. Control animals did not receive an aerosol (DCD). Interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-8, lactate dehydrogenase activity and thiobarbituric acid reactive substances were measured and cells were counted in broncho-alveolar lavage from the right lung after a 3-h warm plus 1-h cold ischemic interval. RESULTS: There were no differences in cells between groups, however cell death was lower in NAC-DCD (10.3 +/- 1.5%) and DCD-NAC (7.83 +/- 1.8%) compared to DCD (18.0 +/- 3.8%). IL-1beta levels (111.5 +/- 28.8 pg/mL and 92.2 +/- 51.0 pg/mL versus 250.3 +/- 56.6 pg/mL) and lactate dehydrogenase activity (1258.0 +/- 440.9 U/L and 1606.0 +/- 289.0 U/L versus 2848.0 +/- 760.9 U/L) were significantly lower in NAC-DCD and DCD-NAC compared with DCD, respectively. These postischemic inflammatory markers correlated with functional parameters upon reperfusion of the left lung, reported in a previous study. CONCLUSIONS: Administration of NAC prior to or shortly after circulatory arrest results in a marked reduction of inflammation during the warm ischemic phase.

N-acetyl cysteine pre-treatment attenuates inflammatory changes in the warm ischemic murine lung.

BACKGROUND: The warm ischemic period in non-heart-beating donor lungs may contribute to a higher degree of ischemia-reperfusion injury after lung transplantation. We investigated the impact and timing of administration of N-acetyl cysteine (NAC) on inflammatory parameters. METHODS: Ischemia (I) was induced by clamping the hilum of the left lung for 90 minutes, and some protocols were followed by reperfusion (R) for 4 hours. Mice were divided into nine groups (n = 6/group): three control groups ([sham] (thoracotomy only), [I] and [I+R]); two groups with saline instillation only ([saline+I] and [saline+I+R]); and four experimental groups with NAC (50 mg/kg), administered by instillation ([NAC+I], [NAC+I+R] and [I+NAC+R]) or by aerosol ([NACaero+I+R]). Cell counts and protein levels in bronchoalveolar lavage (BAL) were determined. RESULTS: NAC administered prior to hilar clamping led to a significant decrease in macrophages and lymphocytes and interleukin (IL)-1 beta levels after ischemia. NAC also resulted in significantly fewer macrophages, lymphocytes and neutrophils as well as IL-1 beta, keratinocyte cytokine (KC), monocyte chemoattractant protein (MCP)-1 and IL-6 levels in BAL taken after reperfusion. CONCLUSIONS: NAC treatment prior to warm ischemia attenuates inflammatory changes after both the ischemic and reperfusion periods.

Primary cryptococcal cellulitis in a lung transplant recipient.

In organ transplant recipients there remains controversy whether cutaneous cryptococcal infection represents a primary infection or a manifestation of disseminated cryptococcosis. We describe a lung transplant patient who developed primary cryptococcal cellulitis in the immediate post-operative period. At presentation, disseminated disease was excluded. The patient was treated with liposomal amphotericin B and fluconazole and, in addition, a surgical debridement was performed. Shortly afterwards, computed tomography revealed dissemination to the brain. The patient died of cerebral edema. As there was no involvement of the central nervous system at presentation, we believe that cryptococcal cellulitis was the primary site of infection and origin of dissemination. In this study we review cryptococcosis, which should always be considered in the differential diagnosis of cellulitis in transplant recipients.

Retrograde flush following topical cooling is superior to preserve the non-heart-beating donor lung.

OBJECTIVE: The use of non-heart-beating donors (NHBD) has been propagated as an alternative to overcome the scarcity of pulmonary grafts. Formation of microthrombi after circulatory arrest, however, is a major concern for the development of reperfusion injury. We looked at the effect and the best route of pulmonary flush following topical cooling in NHBD. METHODS: Non-heparinized pigs were sacrificed by ventricular fibrillation and divided into three groups (n=6 per group). After 1h of in situ warm ischaemia and 2.5h of topical cooling, lungs in group I were retrieved unflushed (NF). In group II, lungs were explanted following an anterograde flush (AF) through the pulmonary artery with 50 ml/kg Perfadex (6 degrees C). Finally, in group III, lungs were retrieved after an identical but retrograde flush (RF) via the left atrium. Flush effluent was sampled at intervals to measure haemoglobin concentration. Performance of the left lung was assessed during 60 min in our ex vivo reperfusion model. Wet-to-dry weight ratio (W/D) of both lungs was calculated as an index of pulmonary oedema. IL-1beta and TNF-alpha protein levels in bronchial lavage fluid from both lungs were compared between groups. RESULTS: Haemoglobin concentration (g/dl) was higher in the first effluent in RF versus AF (3.4+/-1.1 vs 0.6+/-0.1; p<0.05). Pulmonary vascular resistance (dynes x s x cm(-5)) was 975+/-85 RF versus 1567+/-98 AF and 1576+/-88 NF at 60 min of reperfusion (p<0.001). Oxygenation (mmHg) and compliance (ml/cmH(2)O) were higher (491+/-44 vs 472+/-61 and 430+/-33 NS, 22+/-3 vs 19+/-3 and 14+/-1 NS, respectively) and plateau airway pressure (cmH(2)O) was lower (11+/-1 vs 13+/-1 and 13+/-1 NS) after RF versus AF and NF, respectively. No differences in cytokine levels or in W/D ratios were observed between groups after reperfusion. Histology demonstrated microthrombi more often present after AF and NF compared to RF. CONCLUSION: Retrograde flush of the lung following topical cooling in the NHBD results in a better washout of residual blood and microthrombi and subsequent reduced pulmonary vascular resistance upon reperfusion.

Lung transplantation: a 15-year single-center experience.

During the past decade, the outcome after lung transplantation has improved due to a substantial reduction in the immediate postoperative and perioperative mortality that resulted from better surgical techniques, anaesthetic and perioperative management and more intense antibiotic, antifungal and antiviral prophylaxis. However, according to the International Society for Heart and Lung transplantation (ISHLT) Registry, the long-term survival has not improved much in recent years and mortality is most often due to the development of chronic allograft dysfunction, infections, posttransplant lymphoproliferative disorders and other tumours. Although treatment options have improved for most of these issues, therapy for chronic allograft dysfunction has been very disappointing. Recent observations using azithromycin and antireflux surgery may shed more light on the pathophysiology and perhaps the outcome of this debilitating condition. We hope that better prevention and treatment of chronic allograft dysfunction will result in better long-term survival after lung transplantation.