Oesophageal stasis is a risk factor for chronic lung allograft dysfunction and allograft failure in lung transplant recipients.

Background: Morbidity and mortality in lung transplant recipients are often triggered by recurrent aspiration events, potentiated by oesophageal and gastric disorders. Previous small studies have shown conflicting associations between oesophageal function and the development of chronic lung allograft dysfunction (CLAD). Herein, we sought to investigate the relationship between oesophageal motility disorders and long-term outcomes in a large retrospective cohort of lung transplant recipients. Methods: All lung transplant recipients at the Toronto Lung Transplant Program from 2012 to 2018 with available oesophageal manometry testing within the first 7 months post-transplant were included in this study. Patients were categorised according to the Chicago Classification of oesophageal disorders (v3.0). Associations between oesophageal motility disorders with the development of CLAD and allograft failure (defined as death or re-transplantation) were assessed. Results: Of 487 patients, 57 (12%) had oesophagogastric junction outflow obstruction (OGJOO) and 47 (10%) had a disorder of peristalsis (eight major, 39 minor). In a multivariable analysis, OGJOO was associated with an increased risk of CLAD (HR 1.71, 95% CI 1.15-2.55, p=0.008) and allograft failure (HR 1.69, 95% CI 1.13-2.53, p=0.01). Major disorders of peristalsis were associated with an increased risk of CLAD (HR 1.55, 95% CI 1.01-2.37, p=0.04) and allograft failure (HR 3.33, 95% CI 1.53-7.25, p=0.002). Minor disorders of peristalsis were not significantly associated with CLAD or allograft failure. Conclusion: Lung transplant recipients with oesophageal stasis characterised by OGJOO or major disorders of peristalsis were at an increased risk of adverse long-term outcomes. These findings will help with risk stratification of lung transplant recipients and personalisation of treatment for aspiration prevention.

Pulmonary epithelial markers in phenotypes of chronic lung allograft dysfunction.

BACKGROUND: Airway epithelial injury is thought to be a key event in the pathogenesis of chronic lung allograft dysfunction (CLAD). We investigated whether markers of epithelial activity and injury in bronchoalveolar lavage fluid (BAL) correlate with CLAD diagnosis and major CLAD phenotypes: bronchiolitis obliterans syndrome (BOS) vs restrictive allograft syndrome (RAS)-related phenotypes (including RAS, mixed phenotype, and all other patients with RAS-like opacities). METHODS: CLAD status and phenotypes were retrospectively determined in a cohort of all consecutive adult, first, bilateral lung transplants performed 2010-2015, with available BAL samples. All patients with RAS-related phenotypes were included and 1:1 matched with BOS patients based on the time from transplant to CLAD-onset. Subjects who were CLAD-free for a minimum of 3 years post-transplant were 1:1 matched to CLAD patients and included as controls. Proteins that maintain the barrier function of the airway epithelial mucosa (club cell secretory protein, surfactant protein-D and epithelial mucins: MUC1, MUC5AC, MUC5B, MUC16), as well as epithelial cell death markers (M30&M65 representing epithelial cell apoptosis and overall death, respectively), were measured in BAL obtained within 6-months post CLAD onset using a double-sandwich ELISA or a multiplex bead assay. Protein levels were compared using Mann-Whitney-U-test. Association between protein levels and graft survival was assessed using Cox proportional hazards models, adjusted for CMV serology mismatch status and CLAD phenotype. RESULTS: Fifty-four CLAD (27 BOS, 11 RAS, 7 mixed, 9 others with RAS-like opacities) patients and 23 CLAD-free controls were included. Median BAL levels were significantly higher in patients with CLAD compared to CLAD-free controls for M30 (124.5 vs 88.7 U/L), MUC1 (6.8 vs 3.2 pg/mL), and MUC16 (121.0 vs 30.1 pg/mL). When comparing CLAD phenotypes, M30 was significantly higher in patients with RAS-related phenotypes than BOS (160.9 vs 114.6 U/L). In multivariable models, higher M30 and MUC5B levels were associated with decreased allograft survival after CLAD onset independent of phenotype (p < 0.05 for all). CONCLUSIONS: Airway epithelial mucins and cell death markers are enhanced in the BAL of patients with CLAD and can assist in differentiating between CLAD phenotypes and post-CLAD outcomes. Abnormal airway mucin expression and epithelial cell death may be involved in the pathogenesis of CLAD, and therefore their detection may aid in future selection of targeted therapies.

Triaging donor lungs based on a microaspiration signature that predicts adverse recipient outcome.

BACKGROUND: Aspiration is a relative contraindication to accepting donor lungs for transplant and is currently assessed by visual inspection of the airways via bronchoscopy. However, this method is limited as it does not assess for microaspiration. Bile acids measured in large airway bronchial wash (LABW) samples have been shown to be a marker of aspiration in lung transplant recipients. Herein, we investigate the utility of measuring total bile acids (TBA) in donor LABW to predict performance of donor lungs and recipient outcomes. METHODS: TBA was measured in 605 consecutive lung donors at the Toronto Lung Transplant Program. TBA levels were compared in donor lungs deemed unsuitable for transplant, requiring further assessment on ex vivo lung perfusion (EVLP), and those suitable for direct transplantation using Mann-Whitney-U tests. Relationships between LABW TBA concentrations and recipient outcomes were evaluated using multivariable Cox-PH models and log-rank analysis. RESULTS: Donor TBA was highest in lungs deemed unsuitable for transplant and correlated with clinical assessment of aspiration. LABW TBA concentration correlated with calcium, decreased pH, and increased pro-inflammatory mediators in EVLP perfusate. TBA cut-off of 1245 nM was able to differentiate donor lungs directly declined from those suitable for direct transplantation with a 91% specificity (AUROC: 73%). High donor TBA status was associated with the increased rate of primary graft dysfunction, longer time to extubation, and shorter time to chronic lung allograft dysfunction. CONCLUSIONS: In a large retrospective cohort, we observed that donor LABW TBA was associated with suitability of donor lungs for transplant, performance of the organ on EVLP, and adverse recipient outcomes.

Immunosuppressive Therapy in Lung Transplantation.

Long term survival and quality of life after lung transplantation are still affected by the development of chronic lung graft dysfunction (CLAD). CLAD is the number one cause of death one year after transplant; and there is no effective therapy available to date. Transplant centers' approaches include perioperative immunosuppression, maintenance immunosuppression, and the treatment of eventual rejection. This review will focus on maintenance immunosuppression and the available data that support these strategies, as well as a brief description of our desensitization protocol and immunologic risk stratification. Optimization of immunosuppression is key to increase survival and graft function in transplant recipients, mostly through the combination of drugs. Since the therapeutic options to manage CLAD are still very limited, more studies are necessary to test new therapies and to clarify the potential role of new agents.

A Rare Case of Gastric Variceal Hemorrhage Secondary to Infiltrative B-Cell Lymphoma.

Portal hypertension commonly arises in the setting of advanced liver cirrhosis and is the consequence of increased resistance within the portal vasculature. Less commonly, left-sided noncirrhotic portal hypertension can develop in a patient secondary to isolated obstruction of the splenic vein. We present a rare case of left-sided portal hypertension and isolated gastric varices in a patient with large B-cell lymphoma, who was treated with splenic artery embolization. The patient is a 73-year-old male with no previous history of liver disease, who presented with coffee ground emesis and melena. On admission to hospital, he was found to have a hemoglobin level of 3.4 g/l. Emergent esophagogastroduodenoscopy showed isolated bleeding gastric varices (IGV1 by Sarin classification) in the fundus and cardia with subsequent argon plasma coagulation injection. He was transferred to our tertiary center where work-up revealed normal liver function tests, and abdominal ultrasound showed patent hepatic/portal vasculature without cirrhosis. MRI demonstrated a large heterogeneously enhancing mass in the pancreatic tail, with invasion into the spleen and associated splenic vein thrombosis. Surgery consultation was obtained, but urgent splenectomy was not recommended. The patient instead underwent splenic artery embolization to prevent future bleeding from his known gastric varices. Pathology from a CT-guided biopsy was consistent with diffuse large B-cell lymphoma. PET imaging showed uptake in the splenic hilum/pancreatic tail region with no additional metastatic involvement. He was evaluated by the Hematology Department to initiate R-CHOP chemotherapy. During his outpatient follow-up, he reported no further episodes of melena or hematemesis. To the best of our knowledge, there have only been two published case reports of large B-cell lymphoma causing upper gastrointestinal bleeding from isolated gastric varices. These cases were treated with splenectomy or chemotherapy alone. Thus far, splenectomy has been the standard treatment approach for splenic vein thrombosis with clinical complication, such as gastric variceal bleeding. We present a case of successful treatment of bleeding isolated gastric varices using a less invasive and less morbid approach through splenic artery embolization. This case highlights the need for an increased awareness of the diverse etiologies of left-sided portal hypertension and isolated gastric varices, as well as the consideration of minimally invasive management strategies.