Early fundoplication is associated with slower decline in lung function after lung transplantation in patients with gastroesophageal reflux disease

Concurrent abnormal non-acid reflux is associated with additional chronic rejection risk in lung transplant patients with increased acid exposure

Acid reflux has been associated with allograft injury and rejection in lung transplant patients; however, the pathogenic role of non-acid reflux remains debated. We aimed to evaluate the impact of concurrent abnormal non-acid reflux with acid reflux on chronic rejection in lung transplant patients with acid reflux. This was a retrospective cohort study of lung transplant recipients who underwent pre-transplant combined impedance-pH study off acid suppression. Only subjects with acid exposure >4% were included. Non-acid reflux (pH > 4) episodes >27 was considered abnormal per prior normative studies. Chronic rejection was defined as chronic lung allograft dysfunction (CLAD) per International Society for Heart and Lung Transplantation criteria. Time-to-event analyses were performed using Cox proportional hazards and Kaplan-Maier methods, with censoring at death, anti-reflux surgery, or last follow-up. In total, 68 subjects (28 abnormal/40 normal non-acid reflux) met inclusion criteria for the study. Baseline demographic/clinical characteristics were similar between groups. Among this cohort of patients with increased acid exposure, subjects with concurrent abnormal non-acid reflux had significantly higher risk of CLAD than those without on Kaplan-Meier analysis (log-ranked P = 0.0269). On Cox multivariable regression analysis controlling for body mass index, age at transplantation, and proton pump inhibitor use, concurrent abnormal non-acid reflux remained independently predictive of increased CLAD risk (hazard ratio 2.31, confidence interval: 1.03-5.19, P = 0.04). Presence of concurrent abnormal non-acid reflux in lung transplant subjects with increased acid exposure is associated with additional risk of chronic rejection. Non-acid reflux may also contribute to pathogenicity in lung allograft injury/rejection, supporting a potential role for impedance-based testing in this population.

Update on extraesophageal manifestations of gastroesophageal reflux

PURPOSE OF REVIEW

Symptoms/complications related to extraesophageal reflux (EER) are increasingly prevalent presentations and pose significant challenges for clinicians. We summarize and discuss clinical advances and developments in pathophysiology, testing and treatment algorithms of upper/lower airway manifestations of EER.

RECENT FINDINGS

Growing evidence supports likely multifactorial causes of laryngeal symptoms, including EER, oropharyngeal pathologies, allergic conditions, and cognitive-affective processes (brain-larynx interaction). Diagnostic paradigm for laryngopharyngeal reflux (LPR) is shifting towards a personalized approach with noninvasive strategies/prediction tools to risk-stratify patients for upfront reflux testing over empiric acid suppression trials. Management should be multipronged to include antireflux therapies and treatments targeting other causes. Lower airway complications of EER may result in lung dysfunction and poor transplant outcomes. Esophageal symptoms are often absent and routine esophageal/reflux testing to guide timely antireflux therapies may lead to improved outcomes. Modalities that leverage impedance technology may be important, given the potential role of nonacidic reflux. Novel impedance-based metrics such as mean nocturnal baseline impedance and postreflux swallow-induced peristaltic wave index may provide adjunctive diagnostic values.

SUMMARY

Standardized approach to diagnosis/management of EER should include multidisciplinary care teams and consider different phenotypes, nonreflux contributors, and the complex gut-airway relationships. Prompt antireflux therapies after careful candidate selection may improve outcomes of these airway complications.

Optimizing the prelung transplant candidate

PURPOSE OF REVIEW

Lung transplant outcomes are impacted by multiple modifiable risk factors. Candidate deterioration on the wait list remains problematic. Innovative technology and strategies to identify and impact pretransplant morbidity have improved short- and long-term outcomes. We focus our review on recent advances in pretransplant recipient assessment and optimization.

RECENT FINDINGS

Advancements in recipient management have focused on risk factor identification for adverse outcomes and the development of a lung transplant specific frailty assessment. Early surgical correction of gastroesophageal reflux disease (GERD), including the use of partial fundoplication in the setting of esophageal dysmotility, leads to improvements in graft function/longevity. New evidence supports expanding criteria for extracorporeal life support as a bridge to transplant.

SUMMARY

Candidate optimization requires early intervention to limit functional deterioration potentially contributing to adverse outcomes. Frailty can be identified with a transplant specific frailty assessment, and positively impacted with dedicated rehabilitation. Pretransplant frailty is reversible following transplant and should be considered in the context of overall fitness at the time of candidate selection. Invasive support modes including extracorporeal membrane oxygenation (ECMO) are appropriate to preserve strength and mobility, with awake, ambulatory ECMO preferred. The deleterious effect of GERD on graft function can be managed with early fundoplication over medical management alone.

Pulmonary and esophageal function in lung transplantation: Fundamental principles and clinical application

The lungs and esophagus have a close anatomical and physiological relationship. Over the years, reflux-induced pulmonary injury has gained wider recognition, but the full effects of pulmonary disease on esophageal function are still unknown. Intrathoracic pressure dynamics potentially affect esophageal function, especially in patients with end-stage lung disease, both obstructive and restrictive. Lung transplantation is the only viable option for patients with end-stage pulmonary disease and has provided us with a unique opportunity to study these effects as transplantation restores the intrathoracic environment. Esophageal and foregut functional testing before and after transplantation provide insights into the pathophysiology of the foregut-pulmonary axis, such as how underlying pulmonary disease and intrathoracic pressure changes affect esophageal physiology. This review summarizes the available literature and shares the research experience of a lung transplant center, covering topics such as pre- and posttransplant foregut function, esophageal motility in lung transplant recipients, immune-mediated mechanisms of graft rejection associated with gastroesophageal reflux, and the role of antireflux surgery in this population.

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.

Acute transcutaneous electrical stimulation (TES) augments esophageal contractility in patients with weak peristalsis

BACKGROUND

Lung transplantation (LTx) remains controversial in patients with absent peristalsis (AP) given the increased risk for gastroesophageal reflux (GER), and chronic lung allograft dysfunction. Furthermore, specific treatments to facilitate LTx in those with AP have not been widely described. Transcutaneous Electrical Stimulation (TES) has been reported to improve foregut contractility in LTx patients and therefore we hypothesize that TES may augment the esophageal motility of patients with ineffective esophageal motility (IEM).

METHODS

We included 49 patients, 14 with IEM, 5 with AP, and 30 with normal motility. All subjects underwent standard high-resolution manometry and intraluminal impedance (HRIM) with additional swallows as TES was delivered.

RESULTS

TES induced a universal impedance change observable in real-time by a characteristic spike activity. TES significantly augmented the contractile vigor of the esophagus measured by the distal contractile integral (DCI) in patients with IEM [median DCI (IQR) 0 (238) mmHg-cm-s off TES vs. 333 (858) mmHg-cm-s on TES; p = .01] and normal peristalsis [median DCI (IQR) 1545 (1840) mmHg-cm-s off TES vs. 2109 (2082) mmHg-cm-s on TES; p = .01]. Interestingly, TES induced measurable contractile activity (DCI > 100 mmHg-cm-s) in three out of five patients with AP [median DCI (IQR) 0 (0) mmHg-cm-s off TES vs. 0 (182) mmHg-cm-s on TES; p < .001].

CONCLUSION

TES acutely augmented contractile vigor in patients with normal and weak/ AP. The use of TES may positively impact LTx candidacy, and outcomes for patients with IEM/AP. Nevertheless, further studies are needed to determine the long-term effects of TES in this patient population.

Tolerability and Feasibility of the Upper Esophageal Sphincter Assist Device in Preventing Acute and Chronic Allograft Rejection Among Lung Transplant Recipients

GOALS

We aimed to evaluate a novel upper esophageal sphincter (UES) assist device loaner program for the prevention of acute cellular rejection and chronic lung allograft dysfunction among lung transplant (LTx) recipients.

BACKGROUND

Laryngopharyngeal reflux can lead to chronic microaspiration and LTx rejection. The UES assist device applies external pressure at the level of UES to decrease reflux.

STUDY

We prospectively enrolled and issued UES assist devices to consecutive transplant patients referred for gastrointestinal motility testing from 2016 to 2020. Device tolerability was defined by successful utilization as a bridge to ambulatory pH monitoring and/or antireflux procedure, or as permanent therapy. Incidence of rejection was analyzed before, during, and after device implementation.

RESULTS

Twenty-six participants were issued devices (15 pathologic, 5 physiological, 6 unknown reflux status), none of whom developed acute rejection episodes or chronic lung allograft dysfunction while using the device. Thirteen adopted the device promptly after transplantation (mean 1.7 mo) and remained free of rejection episodes over a mean 24.7 months of follow-up. Among those with pathologic reflux, lag time to device adoption strongly correlated with the development of rejection ( r =0.8, P =0.0006). There was no such correlation among those with physiological reflux. Five developed acute rejection after device return.

CONCLUSIONS

The device was tolerated by a majority of LTx patients and appears feasible as a barrier measure in the prevention of rejection. Delayed treatment of laryngopharyngeal reflux may lead to early allograft failure; therefore, the UES assist device should be given important consideration in transplant protection.

Pre-Lung transplant reflux testing demonstrates high prevalence of gastroesophageal reflux in cystic fibrosis and reduces chronic rejection risk

BACKGROUND

Gastroesophageal reflux (GER) has been associated with poor outcomes after lung transplantation for chronic lung disease, including increased risk of chronic rejection. GER is common in cystic fibrosis (CF), but factors influencing the likelihood of pre-transplant pH testing, and the impact of testing on clinical management and transplant outcomes in patients with CF are unknown.

AIM

To evaluate the role of pre-transplant reflux testing in the evaluation of lung transplant candidates with CF.

METHODS

This was a retrospective study from 2007-2019 at a tertiary medical center that included all patients with CF undergoing lung transplant. Patients with pre-transplant anti-reflux surgery were excluded. Baseline characteristics (age at transplantation, gender, race, body mass index), self-reported GER symptoms prior to transplantation, and pre-transplant cardiopulmonary testing results, were recorded. Reflux testing consisted of either 24-h pH- or combined multichannel intraluminal impedance and pH monitoring. Post-transplant care included a standard immunosuppressive regimen, and regular surveillance bronchoscopy and pulmonary spirometry in accordance with institutional practice as well as in symptomatic patients. The primary outcome of chronic lung allograft dysfunction (CLAD) was defined clinically and histologically per International Society of Heart and Lung Transplantation criteria. Statistical analysis was performed with Fisher’s exact test to assess differences between cohorts, and time-to-event Cox proportional hazards modeling.

RESULTS

After applying inclusion and exclusion criteria, a total of 60 patients were included in the study. Among all CF patients, 41 (68.3%) completed reflux monitoring as part of pre-lung transplant evaluation. Objective evidence of pathologic reflux, defined as acid exposure time > 4%, was found in 24 subjects, representing 58% of the tested group. CF patients with pre-transplant reflux testing were older (35.8 vs 30.1 years, P = 0.01) and more commonly reported typical esophageal reflux symptoms (53.7% vs 26.3%, P = 0.06) compared to those without reflux testing. Other patient demographics and baseline cardiopulmonary function did not significantly differ between CF subjects with and without pre-transplant reflux testing. Patients with CF were less likely to undergo pre-transplant reflux testing compared to other pulmonary diagnoses (68% vs 85%, P = 0.003). There was a decreased risk of CLAD in patients with CF who underwent reflux testing compared to those who did not, after controlling for confounders (Cox Hazard Ratio 0.26; 95%CI: 0.08-0.92).

CONCLUSION

Pre-transplant reflux testing revealed high prevalence of pathologic reflux in CF patients and was associated with decreased risk of CLAD. Systematic reflux testing may enhance outcomes in this patient population.

Laparoscopic fundoplication after lung transplantation does not appear to alter lung function trajectory

BACKGROUND

The primary aim of this study was to determine if allograft function in lung transplant (LTx) recipients improves or stabilizes after laparoscopic fundoplication (LF). The secondary aim was to examine the differences in forced expiratory volume in 1 second (FEV1) before and after LF for various subgroups to identify patients who obtained a superior respiratory outcome after LF, and potential predictive factors for this outcome.

METHODS

Retrospective analysis of consecutive LTx recipients undergoing LF at a single centre in Brisbane, Australia between 2004 and 2018. 149/431 proceeded to LF after clinical review and pH study. Regular pre- and post-fundoplication pulmonary function tests were collected from participants. Data were analyzed with linear mixed models, random intercept models, the Reliable Change Index (RCI), and graphical and visual analysis of the trajectory of FEV1.

RESULTS

There was 100% follow-up. After Bonferroni adjustment for multiple comparison was performed, none of the models demonstrated statistical significance. The Reliable Change Index showed one patient had a significant improvement in lung function across that time period, while nine had a significant reduction. The rate of change before and after LF was similar for the 132/149 patients for whom the first and last pre- and post-LF FEV1 values were available. A subset of patients had a considerable reduction in their FEV1 in the peri-operative period (i.e., a large difference between the first measurement post-LF and the final measurement pre-LF).

CONCLUSION

In the largest published cohort to date, LF performed in a high-volume center did not appear to alter the reduction in allograft function seen with time.

A potential mechanism by which aspiration of duodenogastric fluid augments the risk for bronchiolitis obliterans syndrome after lung transplantation

OBJECTIVE

Aspiration of duodenogastric refluxate may damage the respiratory epithelium of lung allografts in transplant recipients. We sought to define a mechanism by which aspiration of duodenogastric fluid augments the risk of bronchiolitis obliterans syndrome after lung transplant in a murine model.

METHODS

We analyzed the immunological effects of acute aspiration of duodenogastric fluid (0.5 mL/kg) on transplant naive (strain DBA/2J) and transplanted mice (strain B6D2F1/J to strain DBA/2J). Serum antibodies to the lung self-antigens (SAgs) K-alpha1 tubulin and collagen-V were determined by enzyme-linked immunosorbent assay. Exosomes were isolated from serum, and immunoblot membranes were probed for antibodies to lung SAgs. Lung sections were assessed for fibrotic burden and obliterative bronchiolitis lesions by histologic and immunohistochemical analyses, including trichrome staining.

RESULTS

Transplanted mice that received duodenogastric fluid developed higher levels of antibodies to the lung SAgs K-alpha1 tubulin and collagen-V and exosomes with lung SAgs on posttransplant days 14 and 28 than transplanted mice with sham aspiration or transplant naive mice (with and without aspiration). All lung allografts demonstrated severe grade A4 rejection on posttransplant day 14, with the highest mean fibrotic burden and mean number of obliterative bronchiolitis-like lesions per microscopic field on day 28 in recipients with aspiration.

CONCLUSIONS

This study links aspiration of duodenogastric fluid after lung transplant to higher autoimmune responses to lung SAgs and the release of circulating exosomes with lung SAgs, which together promote sustained immune responses leading to extensive lung parenchymal damage and, ultimately, severe obliterative bronchiolitis-the histologic hallmark of bronchiolitis obliterans syndrome.

Routine Reflux Testing Guides Timely Antireflux Treatment to Reduce Acute and Chronic Rejection After Lung Transplantation

INTRODUCTION

Gastroesophageal reflux has been associated with poorer lung transplantation outcomes, although no standard approach to evaluation/management has been adopted. We aimed to evaluate the effect of timely antireflux treatment as guided by routine reflux testing on postlung transplant rejection outcomes.

METHODS

This was a retrospective cohort study of lung transplant recipients at a tertiary center. All patients underwent pretransplant ambulatory pH monitoring. Timely antireflux treatment was defined as proton pump inhibitor initiation or antireflux surgery within 6 months of transplantation. Patients were separated into 3 groups: normal pH monitoring (-pH), increased reflux (+pH) with timely treatment, and +pH with delayed treatment. Rejection outcomes included acute rejection, bronchiolitis obliterans syndrome, and chronic lung allograft dysfunction per International Society for Heart and Lung Transplantation criteria. Time-to-event analyses using Cox proportional hazard models were applied. Patients not meeting outcomes were censored at death or last clinic visit.

RESULTS

One hundred seventy-five patients (59% men/mean 56.3 yr/follow-up: 496 person-years) were included. On multivariable analyses, +pH/delayed treatment patients had higher risks of acute rejection (adjust hazard ratio [aHR]:3.81 [95% confidence interval [CI]: 1.90-7.64], P = 0.0002), bronchiolitis obliterans syndrome (aHR: 2.22 [95% CI: 1.07-4.58], P = 0.03), and chronic lung allograft dysfunction (aHR: 2.97 [95% CI: 1.40-6.32], P = 0.005) than +pH/timely treatment patients. Similarly, rejection risks were increased among +pH/delayed treatment patients vs -pH patients (all P < 0.05). No significant differences in rejection risks were noted between +pH/timely treatment patients and -pH patients. Failure/complications of antireflux treatment were rare and similar among groups.

DISCUSSION

Timely antireflux treatment, as directed by pretransplant reflux testing, was associated with reduced allograft rejection risks and demonstrated noninferiority to patients without reflux. A standardized peri-transplant test-and-treat algorithm may guide timely reflux management to improve lung transplant outcomes.

Utility of bile acids in large airway bronchial wash versus bronchoalveolar lavage as biomarkers of microaspiration in lung transplant recipients: a retrospective cohort study

Background

Bronchoalveolar lavage (BAL) is a key tool in respiratory medicine for sampling the distal airways. BAL bile acids are putative biomarkers of pulmonary microaspiration, which is associated with poor outcomes after lung transplantation. Compared to BAL, large airway bronchial wash (LABW) samples the tracheobronchial space where bile acids may be measurable at more clinically relevant levels. We assessed whether LABW bile acids, compared to BAL bile acids, are more strongly associated with poor clinical outcomes in lung transplant recipients.

Methods

Concurrently obtained BAL and LABW at 3 months post-transplant from a retrospective cohort of 61 lung transplant recipients were analyzed for taurocholic acid (TCA), glycocholic acid (GCA), and cholic acid by mass spectrometry and 10 inflammatory proteins by multiplex immunoassay. Associations between bile acids with inflammatory proteins and acute lung allograft dysfunction were assessed using Spearman correlation and logistic regression, respectively. Time to chronic lung allograft dysfunction and death were evaluated using multivariable Cox proportional hazards and Kaplan–Meier methods.

Results

Most bile acids and inflammatory proteins were higher in LABW than in BAL. LABW bile acids correlated with inflammatory proteins within and between sample type. LABW TCA and GCA were associated with acute lung allograft dysfunction (OR = 1.368; 95%CI = 1.036–1.806; P = 0.027, OR = 1.064; 95%CI = 1.009–1.122; P = 0.022, respectively). No bile acids were associated with chronic lung allograft dysfunction. Adjusted for risk factors, LABW TCA and GCA predicted death (HR = 1.513; 95%CI = 1.014–2.256; P = 0.042, HR = 1.597; 95%CI = 1.078–2.366; P = 0.020, respectively). Patients with LABW TCA in the highest tertile had worse survival compared to all others.

Conclusions

LABW bile acids are more strongly associated than BAL bile acids with inflammation, acute lung allograft dysfunction, and death in lung transplant recipients. Collection of LABW may be useful in the evaluation of microaspiration in lung transplantation and other respiratory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02131-5.

Outcomes of partial fundoplication for GERD-related allograft decline after lung transplantation

INTRODUCTION

Gastroesophageal reflux disease contributes to allograft decline secondary to bronchiolitis obliterans after lung transplantation. Antireflux surgery (ARS) slows the decline in lung function related to GERD. ARS operations range from Nissen fundoplications to partial fundoplications, such as the Toupet and Dor. Research in the general population has indicated that partial fundoplication is effective at controlling reflux. We explored lung function and reflux outcomes in a cohort of lung transplant patients who received partial fundoplications.

METHODS

Data from an institutional lung transplant registry was reviewed for patients between 2009 and 2020 who underwent fundoplication after transplant. Lung transplant patients underwent routine pulmonary function testing. Patients with FEV1 values within 180 days pre-fundoplication and two years post-fundoplication were included in the analysis. All patients referred for fundoplication underwent esophageal pH testing, manometry, UGI, and EGD. Most patients underwent Toupet fundoplication, but those with severe dysmotility underwent Dor fundoplication.

RESULTS

53 patients were included in the analysis. Median time to fundoplication after transplant was 403 days. 48 patients underwent Toupet fundoplication. Five underwent Dor fundoplication. 40% of patients had abnormal high-resolution manometry. A linear mixed-effects model tested for a change in FEV1 trajectory up to two years post-fundoplication with an auto-regressive correlation structure. Post-fundoplication FEV1 values decreased by 7 mL per month, and suggested a slow in the decline by 2 mL per month, but this was not significant (p = 0.8). In patients for whom postoperative DeMeester scores were available (19), there was a decline in acid exposure from a median of 45.8 to 1.8 after ARS (p = 0.0003).

CONCLUSION

Although our results did not reach statistical significance, there was a trend towards a decrease in the rate of decline of allograft function before and after partial fundoplication. In the patients whom results were available, a partial fundoplication appropriately controlled acid exposure.

Recipient Management before Lung Transplantation

Lung transplantation is considered a viable treatment option for patients with end-stage lung disease. Recent decades have seen a gradual increase in the number of lung transplantation patients worldwide, and in South Korea, the case number has increased at least 3-fold during the last decade. Furthermore, the waiting list time is becoming longer, and more elderly patients (>65 years) are undergoing lung transplantation; that is, the patients placed on the waiting list are older and sicker than in the past. Hence, proper management during the pre-transplantation period, as well as careful selection of candidates, is a key factor for transplant success and patient survival. Although referring and transplant centers should address many issues, the main areas of focus should be the timing of referral, nutrition, pulmonary rehabilitation, critical care (including mechanical ventilation and extracorporeal membrane oxygenation), psychological support, and the management of preexisting comorbid conditions (coronary artery disease, diabetes mellitus, gastroesophageal reflux disease, osteoporosis, malignancy, viral infections, and chronic infections). In this context, the present article reviews and summarizes the pre-transplantation management strategies for adult patients listed for lung transplantation.

Impact of gastroesophageal reflux disease on idiopathic pulmonary fibrosis and lung transplant recipients

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is a prevalent subset of interstitial lung disease (ILD) that often progresses to require lung transplantation. Gastroesophageal reflux disease (GERD) is common in the IPF population, and GER-related micro-aspiration appears to be an important risk factor for IPF pathogenesis and for the deterioration of transplanted lung function.

RECENT FINDINGS

Many patients with IPF have elevated esophageal acid exposure on reflux testing despite having no or minimal symptoms. Studies on the effects of medical GERD therapy on IPF-related outcomes have had mixed results. Antireflux surgery is safe in appropriately selected IPF patients, and appears to have potential for slowing the decline of lung function. GERD can persist, improve or develop after lung transplantation, and the presence of GERD is associated with allograft injury and pulmonary function decline in lung transplant recipients.

SUMMARY

Clinicians should have a low threshold to assess for objective evidence of GERD in IPF patients. Antireflux surgery in IPF patients with GERD appears to improve lung function, but further studies are needed before surgical treatment can be recommended routinely in this setting. In lung transplant recipients, reflux testing after transplant is the most accurate way to guide GERD treatment decisions.

Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is a syndrome of progressive lung function decline, subcategorized into obstructive, restrictive, and mixed phenotypes. The trajectory of CLAD is variable depending on the phenotype, with restrictive and mixed phenotypes having more rapid progression and lower survival. The mechanisms driving CLAD development remain unclear, though allograft injury during primary graft dysfunction, acute cellular rejection, antibody-mediated rejection, and infections trigger immune responses with long-lasting effects that can lead to CLAD months or years later. Currently, retransplantation is the only effective treatment.

Current trends in candidate selection, contraindications, and indications for lung transplantation

Lung transplantation is an established treatment option that can improve quality of life and prolong survival for select patients diagnosed with end-stage lung disease. Given the gaps in organ donation and failures to make effective use of available organs, careful selection of candidates for lung transplant remains one of the most important considerations of the transplant community. Toward this end, we briefly reviewed recent trends in pretransplant evaluation, candidate selection, organ allocation, and organ preservation techniques. Since the latest consensus statement regarding appropriate selection of lung transplant candidates, many advances in the science and practice of lung transplantation have emerged and influenced our perspective of ‘contraindications’ to transplant. These advances have made it increasingly possible to pursue lung transplant in patients with risk factors for decreased survival—namely, older recipient age, increased body mass index, previous chest surgery, poorer nutritional status, and presence of chronic infection, cardiovascular disease, or extrapulmonary comorbid conditions. Therefore, we reviewed the updated evidence demonstrating the prognostic impact of these risk factors in lung transplant recipients. Lastly, we reviewed the salient evidence for current trends in disease-specific indications for lung transplantation, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, emphysema due to alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension, among other less common end-stage diseases. Overall, lung transplant remains an exciting field with considerable hope for patients as they experience remarkable improvements in quality of life and survival in the modern era.

Foregut Dysmotility in the Lung Transplant Patient

PURPOSE OF REVIEW

To explore the role of upper gastrointestinal disease in the clinical course of lung transplant patients - including its pathophysiology, diagnostic testing, and treatment options.

RECENT FINDINGS

Gastroesophageal reflux disease (GERD) and foregut motility disorders are more prevalent among end-stage lung disease patients and are associated with poorer outcomes in lung transplant recipients. A proposed mechanism is the exposure of the lung allograft to aspirated contents, resulting in inflammation and rejection. Diagnostic tools to assess for these disorders include multichannel intraluminal impedance and pH (MII-pH) testing, high resolution esophageal manometry (HREM), and gastric emptying scintigraphy. The main treatment options are medical management with acid suppressants and/or prokinetic agents and anti-reflux surgery. In particular, data support the use of early anti-reflux surgery to improve outcomes. Newer diagnostic tools such as MII-pH testing and HREM allow for the identification of both acid and non-acid reflux and esophageal motility disorders, respectively. Recent studies have demonstrated that early anti-reflux surgery within six months post-transplant better protects against allograft injury and pulmonary function decline when compared to late surgery. However, further prospective research is needed to evaluate the short and long-term outcomes of these diagnostic approaches and interventions.

Lung transplantation for interstitial lung disease

Lung transplantation (LTx) can be a life-extending treatment option for patients with advanced and/or progressive fibrotic interstitial lung disease (ILD), especially idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis, sarcoidosis and connective tissue disease-associated ILD. IPF is now the most common indication for LTx worldwide. Several unique features in patients with ILD can impact optimal timing of referral or listing for LTx, pre- or post-transplant risks, candidacy and post-transplant management. As the epidemiology of LTx and community practices have evolved, recent literature describes outcomes and approaches in higher-risk candidates. In this review, we discuss the unique and important clinical findings, course, monitoring and management of patients with IPF and other progressive fibrotic ILDs during pre-LTx evaluation and up to the day of transplantation; the need for co-management with clinical experts in ILD and LTx is emphasised. Some post-LTx complications are unique in these patient cohorts, which require prompt detection and appropriate management by experts in multiple disciplines familiar with telomere biology disorders and infectious, haematological, oncological and cardiac complications to enhance the likelihood of improved outcomes and survival of LTx recipients with IPF and other ILDs.

Aspiration of conjugated bile acids predicts adverse lung transplant outcomes and correlates with airway lipid and cytokine dysregulation

INTRODUCTION

Duodeno-gastroesophageal reflux aspiration is associated with chronic lung allograft dysfunction (CLAD). Reflux aspirate can contain bile acids (BA), functional molecules in the gastro-intestinal tract with emulsifying properties. We sought to determine and quantify the various BA species in airways of the lung transplant recipients to better understand the various effects of aspirated BA that contribute to post-transplantation outcomes.

METHODS

Bronchial washings (BW) were prospectively collected from lung transplant recipients and subsequently assayed by liquid chromatography-mass spectrometry for 13 BA and 25 lipid families. Patients were monitored for CLAD, rejection, inflammation and airway infections.

RESULTS

Detectable BA were present in 45/50 patients (90%) at 3 months after transplant. Elevated BA and predominance of conjugated species were independent predictors of CLAD (hazard ratio 7.9; 95% confidence interval 2.7-23.6; p < 0.001 and 7.3; 2.4-22; p < 0.001, respectively) and mortality (hazard ratio 4.4; 1.5-12.7; p = 0.007 and 4.8; 1.4-15.8; p = 0.01, respectively). High BA associated with increased positive bacterial cultures (60% vs 25%, p = 0.02). Primary conjugated species independently correlated with the rate of bacterial cultures during the first-year post-transplant (Beta coefficient: 0.77; 0.28-1.26; p = 0.003) and changes in airway lipidome and cytokines.

CONCLUSIONS

Higher BA levels and predominance of conjugated BA are independent predictors of chronic lung allograft dysfunction, mortality and bacterial infections. Primary conjugated BA are related to distinct changes in airway lipidome and inflammatory cytokines. This elucidates novel evidence into the mechanism following BA aspiration and proposes novel markers for prediction of adverse post-transplant outcomes.

Esophageal disease in lung transplant patients

There is a very well-established and complex interplay between gastroesophageal reflux and lung disease. This is particularly true in end-stage lung disease and post-lung transplant patients. Numerous studies have shown that in patients who are undergoing pre-lung transplant evaluations for diseases such as idiopathic pulmonary fibrosis (IPF), emphysema, connective tissue disease, there is a high prevalence of gastroesophageal reflux and esophageal dysmotility. Post-lung transplant, many of the reflux issues persist or worsen, and there is some evidence to suggest that this leads to worsened long-term allograft function and bronchiolitis obliterans. Anti-reflux operations in patients with lung disease have been shown to be safe in both the pre and post-lung transplant setting and lead to improved reflux symptoms, as well as protecting against reflux induced allograft dysfunction in the post-lung transplant patients. Barrett’s esophagus and esophageal malignancy are also not unheard of in these patients, and select patients may benefit from operative intervention. This review discusses the links between gastroesophageal reflux and lung transplant patients in both the pre and post-transplant setting. We also review the approach to the workup of esophageal disease in the pre-lung transplant setting as well as the surgical management of this unique group of patients.

Factors associated with esophageal motility improvement after bilateral lung transplant in patients with an aperistaltic esophagus

OBJECTIVES

We reported that esophageal peristalsis can improve after lung transplant (LTx), even in patients with pretransplant esophageal aperistalsis. This improvement was associated with better outcomes. We analyzed preoperative factors and sought to predict persistent aperistalsis or motility improvement in patients with pre-LTx esophageal aperistalsis.

METHODS

Patients with esophageal aperistalsis who underwent LTx between January 2013 and December 2016 were included. Preoperative barium esophagrams were blinded and re-examined; subjective scores were assigned to motility and dilation patterns. Postoperative high-resolution manometry was used to divide patients into 2 groups: persistent esophageal aperistalsis (PEA) or improved esophageal peristalsis (IEP).

RESULTS

We identified 29 patients: 20 with restrictive lung disease, 7 with obstructive lung disease, and 2 with pulmonary arterial hypertension. Post-LTx, 10 patients had PEA and 19 had IEP (mean age, 53.3 ± 6.6 years and 61.2 ± 10.6 years, respectively; P = .04). All 9 patients (100%) with obstructive lung disease or pulmonary arterial hypertension but only 10 of 20 patients (50%) with restrictive lung disease had IEP post-LTx (P = .01). All 4 patients with scleroderma had PEA. Nearly absent contractility on preoperative esophagrams was more prevalent in the PEA group than in the IEP group (100% vs 58.8%; P = .06). No further differences were observed between the groups.

CONCLUSIONS

Patients with esophageal aperistalsis and obstructive lung disease or pulmonary arterial hypertension, but not patients with restrictive lung disease and scleroderma, are likely to have IEP post-LTx. Additional studies may determine whether subjective esophagram assessment can help predict IEP post-LTx in patients with restrictive lung disease without scleroderma.

An update on current treatment strategies for managing bronchiolitis obliterans syndrome after lung transplantation

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS), a subtype of chronic lung allograft dysfunction, is quite common, with up to half of all lung recipients developing BOS within 5 years of transplantation. Preventive efforts are aimed at alleviating known risk factors of BOS development, while the primary goal of treatment is to delay the irreversible, fibrotic airway changes, and progressive loss of lung function.

AREAS COVERED

This narrative review will briefly discuss the updated definition, clinical presentation, pathogenesis, risk factors, and survival after BOS while paying particular attention to the salient evidence for optimal preventive strategies and treatments based on investigations in the modern era.

EXPERT OPINION

Future translational research focused on further characterizing the complex interplay between immune and nonimmune mechanisms mediating chronic lung rejection is the first step toward mitigating risk of allograft injury, improving early disease detection with noninvasive biomarkers, and ultimately, developing an effective, targeted therapy that can extend the life of the lung allograft.

Antireflux surgery and risk of lung cancer by histological type in a multinational cohort study

INTRODUCTION

Airway micro-aspiration might contribute to the proposed associations between gastroesophageal reflux disease (GERD) and some lung diseases, including lung cancer. This study aimed to examine the hypothesis that antireflux surgery decreases the risk of small cell carcinoma, squamous cell carcinoma and adenocarcinoma of the lung differently depending on their location in relation to micro-aspiration.

METHODS

Population-based cohort study including patients having undergone antireflux surgery during 1980-2014 in Denmark, Finland, Iceland, Norway or Sweden. Patients having undergone antireflux surgery were compared with two groups: 1) the corresponding background population, by calculating standardised incidence ratios (SIRs) with 95% confidence intervals (CIs) and 2) non-operated GERD-patients, by calculating hazard ratios (HRs) with 95% CIs using multivariable Cox regression with adjustment for sex, age, calendar period, country, chronic obstructive pulmonary disease and obesity diagnosis or type 2 diabetes.

RESULTS

Among all 812,617 GERD-patients, 46,996 (5.8%) had undergone antireflux surgery. The SIRs were statistically significantly decreased for small cell carcinoma (SIR = 0.57, 95% CI 0.41-0.77) and squamous cell carcinoma (SIR = 0.75, 95% CI 0.60-0.92), but not for adenocarcinoma of the lung (SIR = 0.90, 95% CI 0.76-1.06). The HRs were also below unity for small cell carcinoma (HR = 0.63, 95% CI 0.44-0.90) and squamous cell carcinoma (HR = 0.80, 95% CI 0.62-1.03), but not for adenocarcinoma of the lung (HR = 1.03, 95% CI 0.84-1.26). Analyses restricted to patients with objective GERD (reflux oesophagitis or Barrett's oesophagus) showed similar results.

CONCLUSIONS

This all-Nordic study indicates that patients who undergo antireflux surgery are at decreased risk of small cell carcinoma and squamous cell carcinoma of the lung, but not of adenocarcinoma of the lung.

Esophageal Evaluation for Patients Undergoing Lung Transplant Evaluation: What Should We Do for Evaluation and Management

Lung transplantation is a high-risk, but lifesaving, procedure for patients with end-stage lung disease. Although 1-year survival is high, long-term survival is not nearly as high, due mainly to acute and chronic rejection. Bronchiolitis obliterans syndrome is the most common type of chronic rejection and often leads to poor outcomes. For this reason, esophageal testing in the lung transplant population has become a major issue, and this article discusses the evidence behind esophageal testing, the importance of esophageal dysmotility gastroesophageal reflux disease, both acidic and nonacidic reflux, and aspiration and the treatment of these findings.

Non-acid Reflux: When It Matters and Approach to Management

PURPOSE OF REVIEW

This narrative review focuses on the presentation, contributing factors, diagnosis, and treatment of non-acid reflux. We also propose algorithms for diagnosis and treatment.

RECENT FINDINGS

There is a paucity of recent data regarding non-acid reflux. The recent Porto and Lyon consensus statements do not fully address non-acid reflux or give guidance on classification. However, recent developments in the lung transplantation field, as well as older data in the general population, argue for the importance of non-acid reflux. Extrapolating from the Porto and Lyon consensus, we generally classify pathologic non-acid reflux as impedance events > 80, acid exposure time < 4%, and positive symptom correlation on a standard 24-h pH/impedance test. Other groups not meeting this criteria also deserve consideration depending on the clinical situation. Potential treatments include lifestyle modification, increased acid suppression, alginates, treatment of esophageal hypersensitivity, baclofen, buspirone, prokinetics, and anti-reflux surgery in highly selected individuals. More research is needed to clarify appropriate classification, with subsequent focus on targeted treatments.

Increased Acid Exposure on Pretransplant Impedance-pH Testing Is Associated With Chronic Rejection After Lung Transplantation

GOAL

The goal of this study was to assess the relationship between pretransplant measures of reflux and longer-term outcomes of chronic allograft rejection in lung transplant recipients.

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a primary measure of morbidity and mortality following lung transplantation, and a manifestation of chronic lung allograft dysfunction (CLAD). Acid reflux has been associated with early allograft injury through a proposed mechanism of aspiration and activation of the inflammatory cascade, but its association with chronic rejection is unclear.

STUDY

This was a retrospective cohort study of lung transplant recipients undergoing impedance-pH testing off proton pump inhibitor from 2007 to 2016. Patients with pretransplant antireflux surgery were excluded. Time-to-event analysis using the Cox proportional hazards model was applied to assess the relationship between pretransplant reflux measures and the development of BOS, defined histologically and clinically. A secondary analysis was completed using CLAD as the outcome variable.

RESULTS

Fifty-one subjects (59% men, mean age: 56, mean follow-up: 2.2 y) met inclusion criteria for the study. The BOS endpoint was reached in 13 subjects (28%). In time-to-event analyses, BOS was associated with increased acid exposure, defined as >4.2% of time with pH<4 [hazard ratio (HR): 4.18; 95% confidence interval (CI): 1.31-13.4; P=0.01], and elevated DeMeester score >14.7 (HR: 3.08; 95% CI: 1.02-9.26; P=0.04), with confirmation from Kaplan-Meier analyses. The secondary analysis demonstrated a similar association between increased acid exposure and CLAD (HR: 3.28; 95% CI: 1.09-9.88; P=0.03), which persisted on multivariate models.

CONCLUSION

Increased acid exposure on pretransplant reflux testing was associated with the development of BOS and CLAD, both measures of chronic allograft rejection, after lung transplantation, and may provide clinically relevant information to improve lung allograft survival through aggressive reflux management.

Esophageal contractility increases and gastroesophageal reflux does not worsen after lung transplantation

Gastroesophageal reflux and esophageal dysmotility are common in patients with advanced lung disease and are associated with allograft dysfunction after lung transplantation. The effect of transplantation on reflux and esophageal motility is unclear. The aim of this study was to describe the changes in esophageal function occurring after lung transplantation. A retrospective cohort study was performed on lung transplant candidates evaluated at a tertiary care center between 2015 and 2016. A total of 76 patients who underwent lung transplantation had high-resolution manometry and ambulatory pH-metry before and after transplant. Demographic data, esophageal function testing results, and clinical outcomes such as pulmonary function testing were collected and analyzed using appropriate statistical tests and multivariable regression. Of the 76 patients, 59 (78%) received a bilateral transplant. There was a significant increase in esophageal contractility posttransplant, with an increase in median distal contractile integral from 1470 to 2549 mmHg cm s (P < 0.01). There were 19 patients with Jackhammer esophagus posttransplant, including 15 patients with normal motility pretransplant. Nine patients with ineffective or fragmented peristalsis pretransplant had normal manometry posttransplant. Abnormal pH-metry was observed in 35 (46%) patients pretransplant and 29 (38%) patients posttransplant (P = 0.33). Patients with gastroesophageal reflux disease posttransplant had less improvement in pulmonary function at one year, as measured by forced expiratory volume (P = 0.04). These results demonstrate that esophageal contractility increases significantly after lung transplantation, with an associated change in motility classification. In comparison, gastroesophageal reflux does not worsen, but is associated with worse pulmonary function, posttransplant.

Prevalence and Natural History of Barrett's Esophagus in Lung Transplant: A Single-Center Experience

BACKGROUND

Barrett's esophagus (BE)-intestinal metaplasia in the esophagus-may progress to low-grade dysplasia (LGD), high-grade dysplasia (HGD), and ultimately, invasive esophageal adenocarcinoma (EAC). The course of BE in immunosuppressed lung transplant recipients is unknown.

METHODS

This study retrospectively reviewed the records of patients who underwent lung transplant at a single center, Norton Thoracic Institute in Phoenix, Arizona, between January 1, 2010 and October 31, 2016. Pretransplant esophagram, esophagogastroduodenoscopy, 24-hour pH monitoring, high-resolution manometry, and gastric emptying studies were analyzed.

RESULTS

Of the 466 patients who underwent lung transplant during the study period, 54 (11.59%) had BE on pretransplant esophagogastroduodenoscopy. Of these, 1 patient had HGD before lung transplant. The median age of patients was 64 years (interquartile range, 58.25 to 68.75 years); 66.7% were men. Median follow-up duration was 29.48 months (interquartile range, 19.69 to 37.98 months). Sixteen of 54 patients (29.62%) underwent antireflux surgery after lung transplant. LGD or EAC developed in 3 patients during posttransplant surveillance. One patient had a diagnosis of HGD 24 months after retransplant. She underwent complete endoscopic ablation and was dysplasia-free for 5 months, but ultimately the condition recurred, and she underwent esophagectomy for invasive cancer. Two patients had a diagnosis of LGD 7 and 13 months after lung transplant and were successfully treated with radiofrequency ablation. The rate of progression to dysplasia or EAC was 2.3% per patient-year.

CONCLUSIONS

BE seems to be more prevalent in lung transplant recipients than in the general population. The study findings suggest that patients with BE have a higher risk of BE-to-EAC progression after lung transplant and that HGD may progress rapidly in immunosuppressed patients. More intensive surveillance endoscopy may be required in patients with BE after lung transplant.

Perioperative Management of the Lung Graft Following Lung Transplantation

Perioperative management of patients undergoing lung transplantation is one of the most complex in cardiothoracic surgery. Certain perioperative interventions, such as mechanical ventilation, fluid management and blood transfusions, use of extracorporeal mechanical support, and pain management, may have significant impact on the lung graft function and clinical outcome. This article provides a review of perioperative interventions that have been shown to impact the perioperative course after lung transplantation.