Ex vivo lung perfusion in donation after circulatory death: A post hoc analysis of the Normothermic Ex Vivo Lung Perfusion as an Assessment of Extended/Marginal Donors Lungs trial

OBJECTIVE

Donation after circulatory death (DCD) donors offer the ability to expand the lung donor pool and ex vivo lung perfusion (EVLP) further contributes to this ability by allowing for additional evaluation and resuscitation of these extended criteria donors. We sought to determine the outcomes of recipients receiving organs from DCD EVLP donors in a multicenter setting.

METHODS

This was an unplanned post hoc analysis of a multicenter, prospective, nonrandomized trial that took place during 2011 to 2017 with 3 years of follow-up. Patients were placed into 3 groups based off procurement strategy: brain-dead donor (control), brain-dead donor evaluated by EVLP, and DCD donors evaluated by EVLP. The primary outcomes were severe primary graft dysfunction at 72 hours and survival. Secondary outcomes included select perioperative outcomes, and 1-year and 3-years allograft function and quality of life measures.

RESULTS

The DCD EVLP group had significantly higher incidence of severe primary graft dysfunction at 72 hours (P = .03), longer days on mechanical ventilation (P < .001) and in-hospital length of stay (P = .045). Survival at 3 years was 76.5% (95% CI, 69.2%-84.7%) for the control group, 68.3% (95% CI, 58.9%-79.1%) for the brain-dead donor group, and 60.7% (95% CI, 45.1%-81.8%) for the DCD group (P = .36). At 3-year follow-up, presence observed bronchiolitis obliterans syndrome or quality of life metrics did not differ among the groups.

CONCLUSIONS

Although DCD EVLP allografts might not be appropriate to transplant in every candidate recipient, the expansion of their use might afford recipients stagnant on the waitlist a viable therapy.

Robotic Lobectomy Is Cost-effective and Provides Comparable Health Utility Scores to Video-assisted Lobectomy: Early Results of the RAVAL Trial

OBJECTIVE

The aim of this study was to determine if robotic-assisted lobectomy (RPL-4) is cost-effective and offers improved patient-reported health utility for patients with early-stage non-small cell lung cancer when compared with video-assisted thoracic surgery lobectomy (VATS-lobectomy).

BACKGROUND

Barriers against the adoption of RPL-4 in publicly funded health care include the paucity of high-quality prospective trials and the perceived high cost of robotic surgery.

METHODS

Patients were enrolled in a blinded, multicentered, randomized controlled trial in Canada, the United States, and France, and were randomized 1:1 to either RPL-4 or VATS-lobectomy. EuroQol 5 Dimension 5 Level (EQ-5D-5L) was administered at baseline and postoperative day 1; weeks 3, 7, 12; and months 6 and 12. Direct and indirect costs were tracked using standard methods. Seemingly Unrelated Regression was applied to estimate the cost effect, adjusting for baseline health utility. The incremental cost-effectiveness ratio was generated by 10,000 bootstrap samples with multivariate imputation by chained equations.

RESULTS

Of 406 patients screened, 186 were randomized, and 164 analyzed after the final eligibility review (RPL-4: n=81; VATS-lobectomy: n=83). Twelve-month follow-up was completed by 94.51% (155/164) of participants. The median age was 68 (60-74). There were no significant differences in body mass index, comorbidity, pulmonary function, smoking status, baseline health utility, or tumor characteristics between arms. The mean 12-week health utility score was 0.85 (0.10) for RPL-4 and 0.80 (0.19) for VATS-lobectomy ( P =0.02). Significantly more lymph nodes were sampled [10 (8-13) vs 8 (5-10); P =0.003] in the RPL-4 arm. The incremental cost/quality-adjusted life year of RPL-4 was $14,925.62 (95% CI: $6843.69, $23,007.56) at 12 months.

CONCLUSION

Early results of the RAVAL trial suggest that RPL-4 is cost-effective and associated with comparable short-term patient-reported health utility scores when compared with VATS-lobectomy.

Laparoscopic Toupet fundoplication: a safe and effective anti-reflux option in lung transplant recipients

BACKGROUND

Fundoplication is known to improve allograft outcomes in lung transplant recipients by reducing retrograde aspiration secondary to gastroesophageal reflux disease, a modifiable risk factor for chronic allograft dysfunction. Laparoscopic Nissen fundoplication has historically been the anti-reflux procedure of choice, but the procedure is associated with discernable rates of postoperative dysphagia and gas-bloat syndrome. Laparoscopic Toupet fundoplication, an alternate anti-reflux surgery with lower rates of foregut complications in the general population, is the procedure of choice on our institution's lung transplant protocol. In this work, we evaluated the efficacy and safety of laparoscopic Toupet fundoplication in our lung transplant recipients.

METHODS

A prospective case series of 44 lung transplant recipients who underwent laparoscopic Toupet fundoplication by a single surgeon between September 2018 and November 2020 was performed. Preoperative and postoperative results from 24-h pH, esophageal manometry, gastric emptying, and pulmonary function studies were collected alongside severity of gastroesophageal reflux disease and other gastrointestinal symptoms.

RESULTS

Median DeMeester score decreased from 25.9 to 5.4 after fundoplication (p < 0.0001), while percentage of time pH < 4 decreased from 7 to 1.1% (p < 0.0001). The severity of heartburn and regurgitation were also reduced (p < 0.0001 and p = 0.0029 respectively). Overall, pulmonary function, esophageal motility, gastric emptying, severity of bloating, and dysphagia were not significantly different post-fundoplication than pre-fundoplication. Patients with decreasing rates of FEV1 pre-fundoplication saw improvement in their rate of change of FEV1 post-fundoplication (p = 0.011). Median follow-up was 32.2 months post-fundoplication.

CONCLUSIONS

Laparoscopic Toupet fundoplication provides objective pathologic acid reflux control and symptomatic gastroesophageal reflux improvement in lung transplant recipients while preserving lung function and foregut motility. Thus, laparoscopic Toupet fundoplication is a safe and effective antireflux surgery alternative in lung transplant recipients.

A prospective examination of swallow and cough dysfunction after lung transplantation

OBJECTIVES

Swallow and cough dysfunction are possible surgical complications of lung transplantation (LT). We examined voluntary cough strength, sensorimotor reflexive cough integrity, and swallow-related respiratory rate (RR) across swallowing safety and aspiration response groups in recovering LT recipients.

METHODS

Forty-five LT recipients underwent flexible endoscopic evaluation of swallowing indexed by the validated Penetration Aspiration Scale. RR before and after a 3-ounce water drinking task was measured. Voluntary and reflexive cough screening were performed to index motor and sensory outcomes. T-tests, one-way ANOVAs, and chi-square (odds ratios) were used.

RESULTS

60% of patients exhibited laryngeal penetration (n = 27) and 40% demonstrated tracheal aspiration (n = 18); 72% (n = 13) demonstrated silent aspiration. Baseline RR was higher in aspirators versus non-aspirators (26.5 vs. 22.6, p = 0.04) and in silent aspirators compared to non-silent aspirators (27.9 vs. 20.7, p = 0.01). RR change post-swallowing did not differ between aspiration response groups; however, it was significantly higher in aspirators compared to non-aspirators (3 vs. -2, p = 0.02). Compared to non-silent aspirators, silent aspirators demonstrated reduced voluntary cough peak expiratory flow (PEF; 166 vs. 324 L/min, p = 0.01). PEF, motor and urge to cough reflex cough ratings did not differ between aspirators and non-aspirators. Silent aspirators demonstrated a 7.5 times higher odds of failing reflex cough screening compared to non-silent aspirators (p = 0.07).

CONCLUSIONS

During the acute recovery period, all LT participants demonstrated some degree of unsafe swallowing and reduced voluntary cough strength. Silent aspirators exhibited elevated RR, reduced voluntary cough physiologic capacity to defend the airway, and a clinically distinguishable blunted motor response to reflex cough screening.

Inpatient Management of the Acutely Decompensating Lung Transplant Candidate

Lung allocation in the US changed nearly 15 years ago from time accrued on the waiting list to disease severity and likelihood of posttransplant survival, represented by the lung allocation score (LAS). Notably, the risk of death within a year plays a stronger role on the score calculation than posttransplant survival. While this change was associated with the intended decrease in waitlist mortality (most recently reported at 14.6%), it was predictable that transplant teams would have to care for increasingly older and complex candidates and recipients. This urgency-based allocation also led centers to routinely consider transplanting patients with higher acuity, often hospitalized and, not infrequently, in the intensive care unit (ICU). According to the Scientific Registry for Transplant Recipients, from 2009 to 2019, the proportion of lung recipients hospitalized and those admitted to the ICU at the time of transplant increased from 18.9% to 26.8% and from 9.2% to 16.5%, respectively..

RAVAL trial: Protocol of an international, multi-centered, blinded, randomized controlled trial comparing robotic-assisted versus video-assisted lobectomy for early-stage lung cancer

Background

Retrospective data demonstrates that robotic-assisted thoracoscopic surgery provides many benefits, such as decreased postoperative pain, lower mortality, shorter length of stay, shorter chest tube duration, and reductions in the incidence of common postoperative pulmonary complications, when compared to video-assisted thoracoscopic surgery. Despite the potential benefits of robotic surgery, there are two major barriers against its widespread adoption in thoracic surgery: lack of high-quality prospective data, and the perceived higher cost of it. Therefore, in the face of these barriers, a prospective randomized controlled trial comparing robotic- to video-assisted thoracoscopic surgery is needed. The RAVAL trial is a two-phase, international, multi-centered, blinded, parallel, randomized controlled trial that is comparing robotic- to video-assisted lobectomy for early-stage non-small cell lung cancer that has been enrolling patients since 2016.

Methods

The RAVAL trial will be conducted in two phases: Phase A will enroll 186 early-stage non-small cell lung cancer patients who are candidates for minimally invasive pulmonary lobectomy; while Phase B will continue to recruit until 592 patients are enrolled. After consent, participants will be randomized in a 1:1 ratio to either robotic- or video-assisted lobectomy, and blinded to the type of surgery they are allocated to. Health-related quality of life questionnaires will be administered at baseline, postoperative day 1, weeks 3, 7, 12, months 6, 12, 18, 24, and years 3, 4, 5. The primary objective of the RAVAL trial is to determine the difference in patient-reported health-related quality of life outcomes between the robotic- and video-assisted lobectomy groups at 12 weeks. Secondary objectives include determining the differences in cost-effectiveness, and in the 5-year survival data between the two arms. The results of the primary objective will be reported once Phase A has completed accrual and the 12-month follow-ups are completed. The results of the secondary objectives will be reported once Phase B has completed accrual and the 5-year follow-ups are completed.

Discussion

If successfully completed, the RAVAL Trial will have studied patient-reported outcomes, cost-effectiveness, and survival of robotic- versus video-assisted lobectomy in a prospective, randomized, blinded fashion in an international setting.

Trial registration

ClinicalTrials.gov, NCT02617186. Registered 22-September-2015. https://clinicaltrials.gov/ct2/show/NCT02617186

Effects of Patient and Surgery Characteristics on Persistent Postoperative Pain: A Mediation Analysis

OBJECTIVE

Acute postoperative pain intensity is associated with persistent postsurgical pain (PPP) risk. However, it remains unclear whether acute postoperative pain intensity mediates the relationship between clinical factors and persistent pain.

MATERIALS AND METHODS

Participants from a mixed surgical population completed the Brief Pain Inventory and Pain Catastrophizing Scale before surgery, and the Brief Pain Inventory daily after surgery for 7 days and at 30 and 90 days after surgery. We considered mediation models using the mean of the worst pain intensities collected daily on each of postoperative days (PODs) 1 to 7 against outcomes of worst pain intensity at the surgical site endpoints reflecting PPP (POD 90) and subacute pain (POD 30).

RESULTS

The analyzed cohort included 284 participants for the POD 90 outcome. For every unit increase of maximum acute postoperative pain intensity through PODs 1 to 7, there was a statistically significant increase of mean POD 90 pain intensity by 0.287 after controlling for confounding effects. The effects of female versus male sex (m=0.212, P=0.034), pancreatic/biliary versus colorectal surgery (m=0.459, P=0.012), thoracic cardiovascular versus colorectal surgery (m=0.31, P=0.038), every minute increase of anesthesia time (m=0.001, P=0.038), every unit increase of preoperative average pain score (m=0.012, P=0.015), and every unit increase of catastrophizing (m=0.044, P=0.042) on POD 90 pain intensity were mediated through acute PODs 1 to 7 postoperative pain intensity.

DISCUSSION

Our results suggest the mediating relationship of acute postoperative pain on PPP may be predicated on select patient and surgical factors.

Ex vivo SARS-CoV-2 infection of human lung reveals heterogeneous host defense and therapeutic responses

Cell lines are the mainstay in understanding the biology of COVID-19 infection but do not recapitulate many of the complexities of human infection. The use of human lung tissue is one solution for the study of such novel respiratory pathogens. We hypothesized that a cryopreserved bank of human lung tissue would allow for the ex vivo study of the interindividual heterogeneity of host response to SARS-CoV-2, thus providing a bridge between studies with cell lines and studies in animal models. We generated a cryobank of tissues from 21 donors, many of whom had clinical risk factors for severe COVID-19. Cryopreserved tissues preserved 90% cell viability and contained heterogenous populations of metabolically active epithelial, endothelial, and immune cell subsets of the human lung. Samples were readily infected with HCoV-OC43 and SARS-CoV-2 and demonstrated comparable susceptibility to infection. In contrast, we observed a marked donor-dependent heterogeneity in the expression of IL6, CXCL8, and IFNB1 in response to SARS-CoV-2. Treatment of tissues with dexamethasone and the experimental drug N-hydroxycytidine suppressed viral growth in all samples, whereas chloroquine and remdesivir had no detectable effect. Metformin and sirolimus, molecules with predicted but unproven antiviral activity, each suppressed viral replication in tissues from a subset of donors. In summary, we developed a system for the ex vivo study of human SARS-CoV-2 infection using primary human lung tissue from a library of donor tissues. This model may be useful for drug screening and for understanding basic mechanisms of COVID-19 pathogenesis.

In vivo reprogramming of pathogenic lung TNFR2+ cDC2s by IFNβ inhibits HDM-induced asthma

Asthma is a common inflammatory lung disease with no known cure. Previously, we uncovered a lung TNFR2⁺ conventional DC2 subset (cDC2s) that induces regulatory T cells (T_regs) maintaining lung tolerance at steady state but promotes T_H2 response during house dust mite (HDM)-induced asthma. Lung IFNβ is essential for TNFR2⁺ cDC2s-mediated lung tolerance. Here, we showed that exogenous IFNβ reprogrammed T_H2-promoting pathogenic TNFR2⁺ cDC2s back to tolerogenic DCs, alleviating eosinophilic asthma and preventing asthma exacerbation. Mechanistically, inhaled IFNβ, not IFNα, activated ERK2 signaling in pathogenic lung TNFR2⁺ cDC2s, leading to enhanced fatty acid oxidation (FAO) and lung T_reg induction. Last, human IFNβ reprogrammed pathogenic human lung TNFR2⁺ cDC2s from patients with emphysema ex vivo. Thus, we identified an IFNβ-specific ERK2-FAO pathway that might be harnessed for DC therapy.

Lung transplantation for acute exacerbation of interstitial lung disease

BACKGROUND

Acute exacerbations of interstitial lung diseases (AE-ILD) have a high mortality rate with no effective medical therapies. Lung transplantation is a potentially life-saving option for patients with AE-ILD, but its role is not well established. The aim of this study is to determine if this therapy during AE-ILD significantly affects post-transplant outcomes in comparison to those transplanted with stable disease.

METHODS

We conducted a retrospective study of consecutive patients with AE-ILD admitted to our institution from 2015 to 2018. The comparison group included patients with stable ILD listed for lung transplant during the same period. The primary end-points were in-hospital mortality for patients admitted with AE-ILD and 1-year survival for the transplanted patients.

RESULTS

Of 53 patients admitted for AE-ILD, 28 were treated with medical therapy alone and 25 underwent transplantation. All patients with AE-ILD who underwent transplantation survived to hospital discharge, whereas only 43% of the AE-ILD medically treated did. During the same period, 67 patients with stable ILD underwent transplantation. Survival at 1 year for the transplanted patients was not different for the AE-ILD group versus stable ILD group (96% vs 92.5%). The rates of primary graft dysfunction, post-transplant hospital length-of-stay and acute cellular rejection were similar between the groups.

CONCLUSION

Patients with ILD transplanted during AE-ILD had no meaningful difference in overall survival, rate of primary graft dysfunction or acute rejection compared with those transplanted with stable disease. Our results suggest that lung transplantation can be considered as a therapeutic option for selected patients with AE-ILD.

Successful bridge to lung transplantation with transcatheter aortic valve replacement

End-stage lung disease and advanced cardiac conditions are frequently seen together and represent a clinical dilemma. Even though both issues may be amenable to surgical management, combining lung transplant with surgical valve repair is rarely done and theoretically associated with increased morbidity and mortality risks, especially in elderly patients. Here, we describe 2 patients presenting with end-stage lung disease and significant aortic stenosis who were successfully bridged to lung transplant via transcatheter aortic valve replacement. Patient 1 was a 66-year-old man who underwent a double lung transplant 56 days after transcatheter aortic valve replacement. Patient 2 was a 70-year-old man who underwent a single right lung transplant 103 days after transcatheter aortic valve replacement. Both patients had uneventful postoperative courses and are alive at the 1-year time point with excellent performance status. This report suggests that transcatheter aortic valve replacement may favorably impact lung transplant candidacy for patients with end-stage lung disease in the setting of severe aortic stenosis, likely representing a better alternative to concomitant aortic valve replacement and lung transplant in elderly patients.

Enhanced Mitochondrial DNA Repair Resuscitates Transplantable Lungs Donated After Circulatory Death

BACKGROUND

Transplantation of lungs procured after donation after circulatory death (DCD) is challenging because postmortem metabolic degradation may engender susceptibility to ischemia-reperfusion (IR) injury. Because oxidative mitochondrial DNA (mtDNA) damage has been linked to endothelial barrier disruption in other models of IR injury, here we used a fusion protein construct targeting the DNA repair 8-oxoguanine DNA glycosylase-1 (OGG1) to mitochondria (mtOGG1) to determine if enhanced repair of mtDNA damage attenuates endothelial barrier dysfunction after IR injury in a rat model of lung procurement after DCD.

MATERIALS AND METHODS

Lungs excised from donor rats 1 h after cardiac death were cold stored for 2 h after which they were perfused ex vivo in the absence and presence of mt-OGG1 or an inactive mt-OGG1 mutant. Lung endothelial barrier function and mtDNA integrity were determined during and at the end of perfusion, respectively.

RESULTS AND CONCLUSIONS

Mitochondria-targeted OGG1 attenuated indices of lung endothelial dysfunction incurred after a 1h post-mortem period. Oxidative lung tissue mtDNA damage as well as accumulation of proinflammatory mtDNA fragments in lung perfusate, but not nuclear DNA fragments, also were reduced by mitochondria-targeted OGG1. A repair-deficient mt-OGG1 mutant failed to protect lungs from the adverse effects of DCD procurement.

CONCLUSIONS

These findings suggest that endothelial barrier dysfunction in lungs procured after DCD is driven by mtDNA damage and point to strategies to enhance mtDNA repair in concert with EVLP as a means of alleviating DCD-related lung IR injury.

Towards donor lung recovery-gene expression changes during ex vivo lung perfusion of human lungs

We and others have demonstrated that acellular normothermic ex vivo lung perfusion of high-risk donor lungs can result in posttransplant outcomes equivalent to that of contemporaneous lung transplantation using standard donor lungs. However, the mechanism of this effect remains unclear. Given the restoration of cellular metabolic activity during normothermic perfusion, one possibility is that of lung healing via natural innate recovery mechanisms. We explored this by examining the gene expression changes occurring in human lungs during ex vivo lung perfusion. Human lungs clinically rejected for transplantation were perfused for 12 hours of EVLP with biopsies taken at the start, at 1 hour, at 3 hours, and then every 3 hours thereafter to 12 hours. Temporal changes were identified in 2585 genes using the Short Time-series Expression Miner and used for pathway analysis. Despite increases in endothelial markers of inflammation, circulating leukocyte cell-specific gene expression fell over 12 hours of ex vivo lung perfusion (EVLP), suggesting an interrupted inflammation response secondary to washout of circulating leukocytes. Analysis of these gene changes suggests lung recovery follows specific stages: cellular death, cellular preservation, cellular reorganization, and cellular invasion. EVLP may improve posttransplant lung function by washout of leukocytes and facilitating innate mechanisms of repair.

Extracorporeal membrane oxygenation to facilitate tracheal healing after oesophagogastric catastrophe

Anastomotic leak after oesophagectomy is associated with poor outcomes. We report the successful utilization of venovenous extracorporeal membrane oxygenation in conjunction with tracheal stent to treat and heal multiple tracheal-neo-oesophageal fistulae following oesophagectomy.

Higher M30 and high mobility group box 1 protein levels in ex vivo lung perfusate are associated with primary graft dysfunction after human lung transplantation

BACKGROUND

Ex vivo lung perfusion (EVLP) enables assessment of marginal donor lungs for transplantation, with similar clinical outcomes to conventional lung transplantation. We investigated whether cell death-related proteins in the EVLP perfusate could predict primary graft dysfunction (PGD) after transplantation.

METHODS

M30 (indicating epithelial apoptosis), M65 (indicating total epithelial cell death), and high mobility group box 1 (HMGB-1, related to cell death and inflammation) protein levels in EVLP perfusate were measured by enzyme-linked immunosorbent assay and correlated with clinical outcomes.

RESULTS

From 100 sequential EVLP patients, 79 lungs were transplanted. Patients who were bridged with extracorporeal life support (ECLS, n = 6) or who received lobar/single lung (n = 25) were excluded. PGD grade 3 (partial pressure of arterial oxygen/fraction of inspired oxygen <200 or need for ECLS) developed in 11 at any time within 72 hours after transplantation (PGD Group). PGD grade 3 did not develop in 34 patients (Control Group). M30 was significantly higher in the PGD Group than in the Control Group at 1 hour (PGD: 73.3 ± 24.9, control: 53.9 ± 15.9 U/liter; p < 0.01) and at 4 hours (PGD: 137.0 ± 146.6, Control: 72.4 ± 40.0 U/liter; p = 0.046) of EVLP. The increase of HMGB-1 from 1 to 4 hours of EVLP was significantly greater in the PGD Group (PGD: 37.0 ± 25.4, Control: 7.2 ± 16.8 ng/ml; p < 0.001). Higher levels of or a greater increase in M30 and a greater increase in HMGB-1 were associated with higher mortality in Cox regression.

CONCLUSIONS

Levels of M30 and HMGB-1 in the EVLP perfusate correlate with PGD after lung transplantation and might therefore be useful biomarkers to improve donor lung assessment during EVLP.

A 42-Year-Old Woman With Anemia, Shock, and Ischemic Stroke After Lung Transplantation

CASE PRESENTAION

A 42-year-old woman with mixed connective tissue disease-associated interstitial lung disease underwent bilateral lung transplantation. She had an uneventful surgery and was extubated 3 h later. Induction immunosuppression therapy included methylprednisolone 500 mg intraoperatively, basiliximab (anti-IL-2 monoclonal antibody) on days 0 and 4 after transplantation, and methylprednisolone 125 mg intravenously bid for 2 days following surgery. Maintenance immunosuppression therapy consisted of prednisone 20 mg daily, mycophenolate mofetil 750 mg bid, and enteral tacrolimus 0.5 mg bid. Both the donor and the recipient were seropositive for cytomegalovirus. Infectious disease prophylaxis consisted of valganciclovir, trimethoprim-sulfamethoxazole, and voriconazole.

Soluble Adhesion Molecules During Ex Vivo Lung Perfusion Are Associated With Posttransplant Primary Graft Dysfunction

Ex vivo lung perfusion (EVLP) enables assessment of marginal donor lungs for transplantation. We aimed to discover biomarkers in EVLP perfusate that could predict development of primary graft dysfunction (PGD). From September 2008 to August 2013, 100 clinical EVLPs were performed. Eleven patients developed PGD grade 3 within 72 h after transplant. The non-PGD group consisted of 34 patients without PGD grade 3. Nonbilateral lung transplants or transplant after extracorporeal life support were excluded from analyses. Soluble intercellular adhesion molecule 1 (sICAM-1), soluble VCAM-1 (sVCAM-1), and soluble E selectin (sE-selectin) levels, as markers of endothelial activation, were measured in the perfusate of EVLP by enzyme-linked immunosorbent assay and were correlated with clinical outcome. Levels of sICAM-1 at 1 h and sVCAM-1 at 1 and 4 h were significantly higher in the PGD group compared with the non-PGD group. The sE selectin levels were not statistically different between the study groups. Higher levels of sVCAM-1 at 1 and 4 h were statistically significantly associated with PGD either alone or after adjustment for other PGD risk factors. These adhesion molecules may help identify donor lungs at higher risk of PGD during EVLP.

Ex Vivo Perfusion Treatment of Infection in Human Donor Lungs

Ex vivo lung perfusion (EVLP) is a platform to treat infected donor lungs with antibiotic therapy before lung transplantation. Human donor lungs that were rejected for transplantation because of clinical concern regarding infection were randomly assigned to two groups. In the antibiotic group (n = 8), lungs underwent EVLP for 12 h with high-dose antibiotics (ciprofloxacin 400 mg or azithromycin 500 mg, vancomycin 15 mg/kg, and meropenem 2 g). In the control group (n = 7), lungs underwent EVLP for 12 h without antibiotics. A quantitative decrease in bacterial counts in bronchoalveolar lavage (BAL) was found in all antibiotic-treated cases but in only two control cases. Perfusate endotoxin levels at 12 h were significantly lower in the antibiotic group compared with the control group. EVLP with broad-spectrum antibiotic therapy significantly improved pulmonary oxygenation and compliance and reduced pulmonary vascular resistance. Perfusate endotoxin levels at 12 h were strongly correlated with levels of perfusates tumor necrosis factor α, IL-1β and macrophage inflammatory proteins 1α and 1β at 12 h. In conclusion, EVLP treatment of infected donor lungs with broad-spectrum antibiotics significantly reduced BAL bacterial counts and endotoxin levels and improved donor lung function.

Cardiopulmonary Bypass and Extracorporeal Life Support for Emergent Intraoperative Thoracic Situations

Intraoperative thoracic surgical catastrophes may require extracorporeal circulation modes to support the patient while the appropriate repair is made. Teamwork is key and, given the evidence supporting better performance with the use of simulation and surgical-crisis checklists, their use should be encouraged. Anticipation is another important factor because the results of intrathoracic malignancy resection are clearly superior in the setting of planned cardiopulmonary support. In addition, familiarity with the different modes of support that are currently available can direct the decision-making process toward the best option to facilitate resolution of the intraoperative catastrophe with the least related morbidity.

Low-dose computed tomography volumetry for subtyping chronic lung allograft dysfunction

BACKGROUND

The long-term success of lung transplantation is challenged by the development of chronic lung allograft dysfunction (CLAD) and its distinct subtypes of bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). However, the current diagnostic criteria for CLAD subtypes rely on total lung capacity (TLC), which is not always measured during routine post-transplant assessment. Our aim was to investigate the utility of low-dose 3-dimensional computed tomography (CT) lung volumetry for differentiating RAS from BOS.

METHODS

This study was a retrospective evaluation of 63 patients who had developed CLAD after bilateral lung or heart‒lung transplantation between 2006 and 2011, including 44 BOS and 19 RAS cases. Median post-transplant follow-up was 65 months in BOS and 27 months in RAS. The median interval between baseline and the disease-onset time-point for CT volumetry was 11 months in both BOS and RAS. Chronologic changes and diagnostic accuracy of CT lung volume (measured as percent of baseline) were investigated.

RESULTS

RAS showed a significant decrease in CT lung volume at disease onset compared with baseline (mean 3,916 ml vs 3,055 ml when excluding opacities, p < 0.0001), whereas BOS showed no significant post-transplant change (mean 4,318 ml vs 4,396 ml, p = 0.214). The area under the receiver operating characteristic curve of CT lung volume for differentiating RAS from BOS was 0.959 (95% confidence interval 0.912 to 1.01, p < 0.0001) and the calculated accuracy was 0.938 at a threshold of 85%.

CONCLUSION

In bilateral lung or heart‒lung transplant patients with CLAD, low-dose CT volumetry is a useful tool to differentiate patients who develop RAS from those who develop BOS.

Lung transplantation with donation after circulatory determination of death donors and the impact of ex vivo lung perfusion

The growing demand for suitable lungs for transplantation drives the quest for alternative strategies to expand the donor pool. The aim of this study is to evaluate the outcomes of lung transplantation (LTx) with donation after circulatory determination of death (DCDD) and the impact of selective ex vivo lung perfusion (EVLP). From 2007 to 2013, 673 LTx were performed, with 62 (9.2%) of them using DCDDs (seven bridged cases). Cases bridged with mechanical ventilation/extracorporeal life support were excluded. From 55 DCDDs, 28 (51%) underwent EVLP. Outcomes for LTx using DCDDs and donation after neurological determination of death (DNDD) donors were similar, with 1 and 5-year survivals of 85% and 54% versus 86% and 62%, respectively (p = 0.43). Although comparison of survival curves between DCDD + EVLP versus DCDD-no EVLP showed no significant difference, DCDD + EVLP cases presented shorter hospital stay (median 18 vs. 23 days, p = 0.047) and a trend toward shorter length of mechanical ventilation (2 vs. 3 days, p = 0.059). DCDDs represent a valuable source of lungs for transplantation, providing similar results to DNDDs. EVLP seems an important technique in the armamentarium to safely increase lung utilization from DCDDs; however, further studies are necessary to better define the role of EVLP in this context.

Outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass for lung transplantation

OBJECTIVE

The study objective was to compare the outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass support in lung transplantation.

METHODS

We performed a retrospective cohort study from a prospective database of adult lung transplantations performed at the University of Toronto from 2007 to 2013. Among 673 lung transplantations performed in the study period, 267 (39.7%) required cardiopulmonary support. There were 39 cases of extracorporeal membrane oxygenation (2012-2013) and 228 cases of cardiopulmonary bypass (2007-2013). Patients who were bridged with extracorporeal life support, underwent a concomitant cardiac procedure, received a combined liver or heart transplant, were colonized with Burkholderia cenocepacia, or required emergency cannulation for cardiopulmonary support were excluded. Finally, 33 extracorporeal membrane oxygenation cases were matched with 66 cases of cardiopulmonary bypass according to age (±10 years), lung transplantation indication, and procedure type (bilateral vs single lung transplantation).

RESULTS

Recipient factors such as body mass index and gender were not different between extracorporeal membrane oxygenation and cardiopulmonary bypass groups. Furthermore, donor variables were similar, including age, body mass index, last PaO2/FiO2 ratio, smoking history, positive airway cultures, and donor type (brain death and donation after cardiac death). Early outcomes, such as mechanical ventilation requirement, length of intensive care unit stay, and length of hospital stay, significantly favored extracorporeal membrane oxygenation (median 3 vs 7.5 days, P = .005; 5 vs 9.5 days, P = .026; 19 vs 27 days, P = .029, respectively). Perioperative blood product transfusion requirement was lower in the extracorporeal membrane oxygenation group. The 90-day mortality for the extracorporeal membrane oxygenation group was 6% versus 15% for cardiopulmonary bypass (P = .32).

CONCLUSIONS

Extracorporeal membrane oxygenation may be considered as the first choice of intraoperative cardiorespiratory support for lung transplantation.

Ex vivo lung perfusion

Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs.

Distinct expression patterns of alveolar "alarmins" in subtypes of chronic lung allograft dysfunction

The long-term success of lung transplantation is limited by chronic lung allograft dysfunction (CLAD). The purpose of this study was to investigate the alveolar alarmin profiles in CLAD subtypes, restrictive allograft syndrome (RAS) and bronchiolitis obliterans syndrome (BOS). Bronchoalveolar lavage (BAL) samples were collected from 53 recipients who underwent double lung or heart-lung transplantation, including patients with RAS (n = 10), BOS (n = 18) and No CLAD (n = 25). Protein levels of alarmins such as S100A8, S100A9, S100A8/A9, S100A12, S100P, high-mobility group box 1 (HMGB1) and soluble receptor for advanced glycation end products (sRAGE) in BAL fluid were measured. RAS and BOS showed higher expressions of S100A8, S100A8/A9 and S100A12 compared with No CLAD (p < 0.0001, p < 0.0001, p < 0.0001 in RAS vs. No CLAD, p = 0.0006, p = 0.0044, p = 0.0086 in BOS vs. No CLAD, respectively). Moreover, RAS showed greater up-regulation of S100A9, S100A8/A9, S100A12, S100P and HMGB1 compared with BOS (p = 0.0094, p = 0.038, p = 0.041, p = 0.035 and p = 0.010, respectively). sRAGE did not show significant difference among the three groups (p = 0.174). Our results demonstrate distinct expression patterns of alveolar alarmins in RAS and BOS, suggesting that RAS and BOS may represent biologically different subtypes. Further refinements in biologic profiling will lead to a better understanding of CLAD.

Efficient gene delivery to pig airway epithelia and submucosal glands using helper-dependent adenoviral vectors

Airway gene delivery is a promising strategy to treat patients with life-threatening lung diseases such as cystic fibrosis (CF). However, this strategy has to be evaluated in large animal preclinical studies in order to translate it to human applications. Because of anatomic and physiological similarities between the human and pig lungs, we utilized pig as a large animal model to examine the safety and efficiency of airway gene delivery with helper-dependent adenoviral vectors. Helper-dependent vectors carrying human CFTR or reporter gene LacZ were aerosolized intratracheally into pigs under bronchoscopic guidance. We found that the LacZ reporter and hCFTR transgene products were efficiently expressed in lung airway epithelial cells. The transgene vectors with this delivery can also reach to submucosal glands. Moreover, the hCFTR transgene protein localized to the apical membrane of both ciliated and nonciliated epithelial cells, mirroring the location of wild-type CF transmembrane conductance regulator (CFTR). Aerosol delivery procedure was well tolerated by pigs without showing systemic toxicity based on the limited number of pigs tested. These results provide important insights into developing clinical strategies for human CF lung gene therapy.Molecular Therapy-Nucleic Acids (2013) 2, e127; doi:10.1038/mtna.2013.55; published online 8 October 2013.

Lung transplantation for lymphangioleiomyomatosis: single-center Brazilian experience with no chylothorax

BACKGROUND

Lymphangioleiomyomatosis (LAM), a rare cystic disease characterized by proliferation of smooth muscle cells in the lung interstitium, almost exclusively affects females in their reproductive years. Lung transplantation has been established as effective therapy for end-stage pulmonary LAM.

METHODS

This retrospective study includes lung transplantation patients with LAM at a single institution between 1989 and 2009.

RESULTS

During the study period we performed 300 lung transplantations, and in 10 cases the recipients had LAM. All patients were females with a mean age of 43.8 years. The mean time from the diagnosis to lung transplantation was 5 years. Seven patients had experienced previous pneumothoraces, five of whom were treated with pleurodesis. In all patients we performed a single-lung transplantation (left-sided = 9 and right-sided = 1). In three cases, the pleurodesis was on the same side as the transplantation, with great intraoperative bleeding in one subject (left pleurectomy). There was one early death due to infective endocarditis at posttransplant day 19. The median length of mechanical ventilation was 13 hours, while the mean hospital stay was 16.75 days. There was no case of chylothorax. Late complications included one case of native lung pneumothorax, one diaphragmatic hernia, one posttransplant lymphoproliferative disease, one respiratory sepsis, and one mycobacterial infection. The 1- and 3-year survival rates were 90% and 80%, respectively.

CONCLUSION

Lung transplantation is a feasible therapeutic option for patients with LAM, despite previous ipsilateral pleurodesis. The left-sided predilection for our procedures may have been responsible for the absence of chylothorax in this series.