Anti-reflux surgery for lung transplant recipients in the presence of impedance-detected duodenogastroesophageal reflux and bronchiolitis obliterans syndrome: A study of efficacy and safety

Esophageal Motility Abnormalities in Lung Transplant Recipients With Esophageal Acid Reflux Are Different From Matched Controls

Background/Aims

There is an increased incidence of gastroesophageal reflux disease (GERD) after lung transplantation (LT) that can be associated with graft dysfunction. It is unclear if the underlying esophageal motility changes in GERD are different following LT. This study aimed to use esophageal high-resolution manometry (HRM) to explore GERD mechanisms in LT recipients compared to matched controls.

Methods

This was a retrospective study including patients with pathologic acid reflux who underwent HRM and pH testing at our healthcare facility July 2012 to October 2019. The study included 12 LT recipients and 36 controls. Controls were matched in a 1:3 ratio for age, gender, and acid exposure time (AET).

Results

LT recipients had less hypotensive esophagogastric junction (EGJ) (mean EGJ-contractile integral 89.2 mmHg/cm in LT vs 33.9 mmHg/cm in controls, P < 0.001). AET correlated with distal contractile integral and total EGJ-contractile integral only in LT group (r = -0.79, P = 0.002 and r = -0.57, P = 0.051, respectively).

Conclusions

Following LT, acid reflux is characterized by a less hypotensive EGJ compared to controls with similar AET. The strongest correlation with AET after LT was found to be esophageal peristaltic vigor. These results add to the understanding of reflux after LT and may help tailor an individualized treatment plan.

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.

Enhanced recovery after surgery may mitigate the risks associated with robotic-assisted fundoplication in lung transplant patients

INTRODUCTION

A history of lung transplantation is a risk factor for poor outcomes in patients undergoing laparoscopic fundoplication. We wanted to determine whether enhanced recovery after a robotic-assisted surgery program would mitigate these risks.

METHODS

We performed a single-center retrospective analysis of the Society of Thoracic Surgery database for patients who underwent elective antireflux procedures from 1/2018 to 2/2021 under the enhanced recovery after surgery program using robotic assistance. We identified the patient and surgical characteristics, morbidity, length of stay, and 30-day readmission rates.

RESULTS

Among 386 patients who underwent barrier creation, 41 had previously undergone a lung transplant, either bilateral (n = 28) or single (n = 13). There were no significant differences in postoperative complications (9.8% vs. 5.2%, p = 0.27), median hospital length of stay (1 d vs. 1 d, p = 0.28), or 30-day readmission (7.3% vs. 4.9%, p = 0.46). Bivariate analysis showed that older age (p = 0.03), history of DVT/PE (p < 0.001), history of cerebrovascular events (p = 0.03), opioid dependence (p = 0.02), neurocognitive dysfunction (p < 0.001), and dependent functional status (p = 0.02) were associated with postoperative complications. However, lung transplantation was not associated with an increased risk of postoperative complications (p = 0.28).

DISCUSSION

The risk of surgical complications in patients with a history of lung transplantation may be mitigated by the combination of ERAS and minimally invasive surgery such as robot-assisted surgery.

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.

A perspective on the clinical relevance of weak or nonacid reflux

BACKGROUND

Advances in ambulatory esophageal reflux monitoring that incorporated impedance electrodes to pH catheters have resulted in better characterization of retrograde bolus flow in the esophagus. With pH-impedance monitoring, in addition to acid reflux episodes identified by pH drops below 4.0, weakly acid reflux (WAR, pH 4-7) and nonacid reflux (NAR, pH >7.0) are also recognized, although both may be included under the umbrella term NAR. However, despite identification of ambulatory pH-impedance monitoring, data on clinical relevance and prognostic value of NAR are limited. The Lyon Consensus, an international expert review that defines conclusive metrics for gastroesophageal reflux disease (GERD), identifies NAR as "supportive" but not conclusive for GERD.

PURPOSE

This review provides perspectives on whether NAR fulfills three criteria for clinical relevance: whether NAR sufficiently explains pathogenesis of symptoms, whether it is associated with meaningful manifestations of GERD, and whether it can predict treatment efficacy.

Decreased Lymphocytic Bronchitis Severity in the Era of Azithromycin Prophylaxis

Large-airway lymphocytic inflammation (LB), assessed on endobronchial biopsies, has been associated with acute cellular rejection and chronic lung allograft dysfunction (CLAD). Azithromycin (AZI) prophylaxis has been used to prevent airway inflammation and subsequent CLAD, with inconsistent results. We hypothesized that AZI prophylaxis would be associated with reduced LB, changes in bronchoalveolar lavage (BAL) immune cell populations, and improved CLAD-free survival.

Methods

We compared frequencies of LB from endobronchial biopsies before (N = 1856) and after (N = 975) protocolized initiation of AZI prophylaxis at our center. LB was classified as none, minimal, mild, or moderate by histopathologic analysis. LB grades were compared using ordinal mixed-model regression. Corresponding automated BAL leukocyte frequencies were compared using mixed-effects modeling. The effect of AZI prophylaxis on CLAD-free survival was assessed by a Cox proportional hazards model adjusted for age, sex, ethnicity, transplant indication, and cytomegalovirus serostatus.

Results

Biopsies in the pre-AZI era had 2-fold increased odds (95% confidence interval, 1.5-2.7; P < 0.001) of higher LB grades. LB was associated with BAL neutrophilia in both eras. However, there was no difference in risk for CLAD or death between AZI eras (hazard ratio 1.3; 95% confidence interval, 0.7-2.0; P = 0.45).

Conclusions

Decreased airway inflammation in the era of AZI prophylaxis may represent a direct effect of AZI therapy or reflect other practices or environmental changes. In this cohort, AZI prophylaxis was not associated with improved CLAD-free survival.

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.

Reflux Surgery in Lung Transplantation: A Multicenter Retrospective Study

BACKGROUND

Aspiration has been associated with graft dysfunction after lung transplantation, leading some to advocate for selective use of fundoplication despite minimal data supporting this practice.

METHODS

We performed a multicenter retrospective study at 4 academic lung transplant centers to determine the association of gastroesophageal reflux disease and fundoplication with bronchiolitis obliterans syndrome and survival using Cox multivariable regression.

RESULTS

Of 542 patients, 136 (25.1%) underwent fundoplication; 99 (18%) were found to have reflux disease without undergoing fundoplication. Blanking the first year after transplantation, fundoplication was not associated with a benefit regarding freedom from bronchiolitis obliterans syndrome (hazard ratio [HR], 0.93; 95% CI, 0.58-1.49) or death (HR, 0.97; 95% CI, 0.47-1.99) compared with reflux disease without fundoplication. However, a time-dependent adjusted analysis found a slight decrease in mortality (HR, 0.59; 95% CI, 0.28-1.23; P = .157), bronchiolitis obliterans syndrome (HR, 0.68; 95% CI, 0.42-1.11; P = .126), and combined bronchiolitis obliterans syndrome or death (HR, 0.66; 95% CI, 0.42-1.04; P = .073) in the fundoplication group compared with the gastroesophageal reflux disease group.

CONCLUSIONS

Although a statistically significant benefit from fundoplication was not determined because of limited sample size, follow-up, and potential for selection bias, a randomized, prospective study is still warranted.

Morbidity of antireflux surgery in lung transplant and matched nontransplant cohorts is comparable

BACKGROUND

Safety data on perioperative outcomes of laparoscopic antireflux surgery (LARS) after lung transplantation (LT) are lacking. We compared the 30-day readmission rate and short-term morbidity after LARS between LT recipients and matched nontransplant (NT) controls.

METHODS

Adult patients who underwent LARS between January 1, 2015, and October 31, 2021, were included. The participants were divided into two groups: LT recipients and NT controls. First, we compared 30-day readmission rates after LARS between the LT and NT cohorts. Next, we compared 30-day morbidity after LARS between the LT cohort and a 1-to-2 propensity score-matched NT cohort.

RESULTS

A total of 1328 patients (55 LT recipients and 1273 NT controls) were included. The post-LARS 30-day readmission rate was higher in LT recipients than in the overall NT controls (14.5% vs. 2.8%, p < 0.001). Compared to matched NT controls, LT recipients had a lower prevalence of paraesophageal hernia, a smaller median hernia size, and higher peristaltic vigor. Also compared to the matched NT controls, the LT recipients had a lower median operative time but a longer median length of hospital stay. The proportion of patients with a post-LARS event within 30 postoperative days was comparable between the LT and matched NT cohorts (21.8% vs 14.5%, p = 0.24).

CONCLUSIONS

Despite a higher perceived risk of comorbidity burden, LT recipients and matched NT controls had similar rates of post-LARS 30-day morbidity at our large-volume center with expertise in transplant and foregut surgery. LARS after LT is safe.

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.

Lymphocytic Airway Inflammation in Lung Allografts

Lung transplant remains a key therapeutic option for patients with end stage lung disease but short- and long-term survival lag other solid organ transplants. Early ischemia-reperfusion injury in the form of primary graft dysfunction (PGD) and acute cellular rejection are risk factors for chronic lung allograft dysfunction (CLAD), a syndrome of airway and parenchymal fibrosis that is the major barrier to long term survival. An increasing body of research suggests lymphocytic airway inflammation plays a significant role in these important clinical syndromes. Cytotoxic T cells are observed in airway rejection, and transcriptional analysis of airways reveal common cytotoxic gene patterns across solid organ transplant rejection. Natural killer (NK) cells have also been implicated in the early allograft damage response to PGD, acute rejection, cytomegalovirus, and CLAD. This review will examine the roles of lymphocytic airway inflammation across the lifespan of the allograft, including: 1) The contribution of innate lymphocytes to PGD and the impact of PGD on the adaptive immune response. 2) Acute cellular rejection pathologies and the limitations in identifying airway inflammation by transbronchial biopsy. 3) Potentiators of airway inflammation and heterologous immunity, such as respiratory infections, aspiration, and the airway microbiome. 4) Airway contributions to CLAD pathogenesis, including epithelial to mesenchymal transition (EMT), club cell loss, and the evolution from constrictive bronchiolitis to parenchymal fibrosis. 5) Protective mechanisms of fibrosis involving regulatory T cells. In summary, this review will examine our current understanding of the complex interplay between the transplanted airway epithelium, lymphocytic airway infiltration, and rejection pathologies.

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.

Relationship between FEV1 decline and mortality in patients with bronchiolitis obliterans syndrome-a systematic literature review

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is one of the most severe complications and the leading cause of late mortality and morbidity after lung transplantation (LT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). No approved treatment for BOS is available. This review aimed to systematically identify and summarise the findings regarding the relationship between FEV₁ decline and mortality in patients who developed BOS following LT or allo-HSCT.

METHODS

A systematic literature search was performed in the Medline, Embase and Cochrane reviews databases. Of the 501 potential studies identified 25 met inclusion criteria and were analysed.

RESULTS

Overall, 13 studies reported a relationship between FEV₁ and mortality, and 12 studies reported both mortality and FEV₁ results but did not investigate the relationship between them. There was heterogeneity in the analyses, which investigated the relationship between FEV₁ decline and mortality across the studies in terms of levels of lung functioning, comparison to a control group, treatment, and statistical methodology; nevertheless, a clear and consistent increase in the risk of death associated with FEV₁ decrease was seen in the analysed studies.

CONCLUSIONS

The systematic literature review identified studies and findings that support a relationship between FEV₁ and mortality, with a decrease in FEV₁ being statistically associated with increased risk of death. Knowing that lower FEV₁ levels are associated with higher mortality rates may help assess the condition of a patient with BOS and monitor future treatment effectiveness. However, more evidence is needed to further investigate this relationship and to verify its clinical usefulness.

Identification of Lung Transplant Recipients with a Survival Benefit after Fundoplication

BACKGROUND

Gastroesophageal reflux disease (GERD) and aspiration of enteric contents is associated with worse outcomes after lung transplant. The purpose of this study is to elucidate populations that benefit the most from fundoplication after lung transplant.

METHODS

Lung transplants from 2001-2019 (n=971) were retrospectively reviewed and stratified by a fundoplication before (n=128) or after (n=24) chronic lung allograft dysfunction (CLAD) development vs those who didn't. Patients with a fundoplication prior to CLAD were propensity-matched to those without a fundoplication. The primary outcome of interest was post-transplant survival. Time-to-event rates were calculated using a multivariable Cox proportional hazards model and Kaplan-Meier functions.

RESULTS

A fundoplication prior to CLAD improved post-transplant survival before and after propensity-matching, and remained a significant predictor after adjusting for baseline characteristics (HR:0.57, 95% CI:0.4-0.8, P=0.001). Recipients with a restrictive disorder (HR: 0.46, 95% CI:0.3-0.73, P=0.001), age <65 (HR:0.48, 95% CI:0.32-0.71, P<0.001), and both single (HR:0.47, 95% CI:0.28-0.79, P=0.005) or double (HR:0.55, 95% CI:0.32-0.93, P=0.027) lung transplants had a significant decrease in mortality after fundoplication. The effect was present after excluding early deaths and/or CLAD diagnoses. GERD diagnosed by pH, impedance or EGD was not associated with worse outcomes. Among patients with CLAD, a fundoplication was an independent predictor of post-CLAD survival (HR:0.27, 95% CI:0.12-0.61, P=0.002).

CONCLUSIONS

A fundoplication before or after CLAD development is an independent predictor of survival. Younger patients with restrictive disease, independent of the type of transplant, have a survival benefit. GERD diagnosed by conventional methods was not associated with worse survival.

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.

Pulmonary manifestations of gastroesophageal reflux disease

INTRODUCTION

Gastroesophageal reflux disease (GERD) is a widespread condition with a significant impact on the quality of life and healthcare resources. In addition to its gastrointestinal problems, GERD has been linked to a variety of respiratory diseases either as a direct cause, or as a risk factor to the inability to control or worsening of the disease.

AREAS COVERED

We performed a literature search in the PubMed database for articles addressing GERD and pulmonary diseases. This review will discuss several different pulmonary diseases affected by GERD ranging from upper airway including chronic cough, vocal cord dysfunction, lower airway diseases including COPD, asthma, and bronchiolitis obliterans syndrome to parenchymal diseases such as interstitial lung diseases. The review will discuss several different pulmonary manifestations of GERD and their contribution to patient mortality and morbidity. It will also review the mechanisms leading to these diseases, diagnostic workup, and the role of the available treatment options.

EXPERT OPINION

GERD is often overlooked as a cause of respiratory symptoms and illnesses. The literature is sparse on the relation between GERD and respiratory diseases such as interstitial lung diseases and bronchiolitis obliterans including its role in pathogenesis, mechanisms of lung injury, and whether treatment of GERD is effective in managing such illnesses.

Update in Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation to posttransplant survival. This review highlights the evolving definition of CLAD, risk factors, treatment, and expected outcomes after the development of CLAD.

Long-term outcomes and management of lung transplant recipients

Lung transplantation is an established treatment for patients with end-stage lung disease. Improvements in immunosuppression and therapeutic management of infections have resulted in improved long-term survival and a decline in allograft rejection. Allograft rejection continues to be a serious complication following lung transplantation, thereby leading to acute graft failure and, subsequently, chronic lung allograft dysfunction (CLAD). Bronchiolitis obliterans syndrome (BOS), the most common phenotype of CLAD, is the leading cause of late mortality and morbidity in lung recipients, with 50% having developed BOS within 5 years of lung transplantation. Infections in lung transplant recipients are also a significant complication and represent the most common cause of death within the first year. The success of lung transplantation depends on careful management of immunosuppressive regimens to reduce the rate of rejection, while monitoring recipients for infections and complications to help identify problems early. The long-term outcomes and management of lung transplant recipients are critically based on modulating natural immune response of the recipient to prevent acute and chronic rejection. Understanding the immune mechanisms and temporal correlation of acute and chronic rejection is thus critical in the long-term management of lung recipients.

Lung disease severity in idiopathic pulmonary fibrosis is more strongly associated with impedance measures of bolus reflux than pH parameters of acid reflux alone

BACKGROUND

Gastroesophageal reflux (GER) has been associated with idiopathic pulmonary fibrosis (IPF). Pathogenesis may be related to chronic micro-aspiration. We aimed to assess objective measures of GER on multichannel intraluminal impedance and pH study (MII-pH) and their relationship with pulmonary function testing (PFT) results, and to compare the performance of pH/acid reflux parameters vs corresponding MII/bolus parameters in predicting pulmonary dysfunction in IPF.

METHODS

This was a retrospective cohort study of IPF patients undergoing prelung transplant evaluation with MII-pH off acid suppression, and having received PFT within 3 months. Patients with prior fundoplication were excluded. Severe pulmonary dysfunction was defined using diffusion capacity of the lung for carbon monoxide (DLCO) ≤40%. Six pH/acid reflux parameters with corresponding MII/bolus reflux measures were specified a priori. Multivariate analyses were applied using forward stepwise logistic regression. Predictive value of each parameter for severe pulmonary dysfunction was calculated by area-under-the-receiver-operating-characteristic-curve or c-statistic.

KEY RESULTS

Forty-five subjects (67% M, age 59, 15 mild-moderate vs 30 severe) met criteria for inclusion. Patient demographics and clinical characteristics were similar between pulmonary dysfunction groups. Abnormal total reflux episodes and prolonged bolus clearance time were significantly associated with pulmonary dysfunction severity on univariate and multivariate analyses. No pH parameters were significant. The c-statistic of each pH parameter was lower than its MII counterpart in predicting pulmonary dysfunction.

CONCLUSIONS & INFERENCES

MII/bolus reflux, but not pH/acid reflux, was associated with pulmonary dysfunction in prelung transplant patients with IPF. MII-pH may be more valuable than pH testing alone in characterizing GER in IPF.

Peroral endoscopic myotomy for the treatment of esophageal achalasia: systematic review and pooled analysis

Peroral endoscopic myotomy (POEM) is a novel approach to performing esophageal myotomy for the treatment of achalasia. This review aims to assess subjective and objective metrics of achalasia treatment efficacy, perioperative adverse events and the incidence of postoperative gastroesophageal reflux disease in patients treated with POEM. Secondary aims include a pooled analysis comparison of the clinical outcomes and procedural safety of POEM versus laparoscopic Heller's myotomy (LHM). A systematic review of the literature, up to and including January 15, 2015, was conducted for studies reporting POEM outcomes. Studies comparing POEM to LHM were also included for the purpose of pooled analysis. Outcomes from 1122 POEM patients, from 22 studies, are reported in this systematic review. Minor operative adverse events included capno/pneumo-peritoneum (30.6%), capno/pneumo-thorax (11.0%) and subcutaneous emphysema (31.6%). Major operative adverse events included mediastinal leak (0.3%), postoperative bleeding (1.1%) and a single mortality (0.09%). There was an improvement in lower esophageal sphincter pressure and timed barium esophagram column height of 66% and 80% post-POEM, respectively. Symptom improvement was demonstrated with a pre- and post-POEM Eckardt score ± standard deviation of 6.8 ± 1.0 and 1.2 ± 0.6, respectively. Pre- and post-POEM endoscopy showed esophagitis in 0% and 19% of patients, respectively. The median (interquartile range) points scored for study quality was 15 (14-16) out of total of 32. Pooled analysis of three comparative studies between LHM and POEM showed similar results for adverse events, perforation rate, operative time and a nonsignificant trend toward a reduced length of hospital stay in the POEM group. In conclusion, POEM is a safe and effective treatment for achalasia, showing significant improvements in objective metrics and achalasia-related symptoms. Randomized comparative studies of LHM and POEM are required to determine the most effective treatment modality for achalasia.

Esophageal Dysmotility, Gastro-esophageal Reflux Disease, and Lung Transplantation: What Is the Evidence?

Lung transplantation is an effective and life-prolonging therapy for patients with advanced lung disease (ALD). However, long-term patient survival following lung transplantation is primarily limited by development of an inflammatory and fibrotic process involving the lung allograft known as bronchiolitis obliterans syndrome (BOS). Although the precise cause of BOS remains uncertain and is likely multifactorial, chronic aspiration of gastro-duodenal contents is one possible contributing factor. Multiple small, cross-sectional studies performed over the past two decades have reported a high prevalence of gastro-esophageal reflux disease (GERD) and esophageal dysmotility in the ALD population and several investigations suggest the prevalence may increase following lung transplantation. More recent studies evaluating the direct effect of gastro-duodenal contents on airways have demonstrated a possible biologic link between GERD and BOS. Despite the recent advances in our understanding of BOS, further investigations are needed to establish GERD as a causative factor in its development. This review will discuss the existing literature that has identified an association of GERD with ALD and post-transplant populations, with a focus on recent advances in the field.

Incidence and Risk Factors of Abdominal Complications After Lung Transplantation

BACKGROUND

Due to the underlying diseases and the need for immunosuppression, patients after lung transplantation are particularly at risk for gastrointestinal (GI) complications that may negatively influence long-term outcome. The present study assessed the incidences and impact of GI complications after lung transplantation and aimed to identify risk factors.

METHODS

Retrospective analysis of all 227 consecutively performed single- and double-lung transplantations at the University hospitals of Lausanne and Geneva was performed between January 1993 and December 2010. Logistic regressions were used to test the effect of potentially influencing variables on the binary outcomes overall, severe, and surgery-requiring complications, followed by a multiple logistic regression model.

RESULTS

Final analysis included 205 patients for the purpose of the present study, and 22 patients were excluded due to re-transplantation, multiorgan transplantation, or incomplete datasets. GI complications were observed in 127 patients (62%). Gastro-esophageal reflux disease was the most commonly observed complication (22.9%), followed by inflammatory or infectious colitis (20.5%) and gastroparesis (10.7%). Major GI complications (Dindo/Clavien III-V) were observed in 83 (40.5%) patients and were fatal in 4 patients (2.0%). Multivariate analysis identified double-lung transplantation (p = 0.012) and early (1993-1998) transplantation period (p = 0.008) as independent risk factors for developing major GI complications. Forty-three (21%) patients required surgery such as colectomy, cholecystectomy, and fundoplication in 6.8, 6.3, and 3.9% of the patients, respectively. Multivariate analysis identified Charlson comorbidity index of ≥3 as an independent risk factor for developing GI complications requiring surgery (p = 0.015).

CONCLUSION

GI complications after lung transplantation are common. Outcome was rather encouraging in the setting of our transplant center.

Diffuse aspiration bronchiolitis: analysis of 20 consecutive patients

OBJECTIVE

Aspiration can cause a variety of pulmonary syndromes, some of which are not well recognized. The objective of this study was to assess the demographic, clinical, radiological, and histopathological correlates of diffuse aspiration bronchiolitis (DAB), a bronchiolocentric disorder caused by recurrent aspiration.

METHODS

This was a retrospective study of 20 consecutive patients with DAB seen at the Mayo Clinic in Rochester, Minnesota, between January 1, 1998 and June 30, 2014.

RESULTS

The median age of the patients was 56.5 years (range, 22-76 years), and the male/female ratio was 2.3:1.0. In 18 patients, the diagnosis of DAB was based on the results of a lung biopsy; in the 2 remaining patients, it was based on clinical and radiological features, together with documented aspiration observed in a videofluoroscopic swallow study. In 19 patients (95%), we identified predisposing factors for aspiration, including gastroesophageal reflux disease (GERD), drug abuse, and dysphagia. Common presenting features included cough, sputum production, dyspnea, and fever. Twelve patients (60%) had a history of recurrent pneumonia. In all of the patients, chest CT revealed bilateral pulmonary infiltrates consisting of micronodules and tree-in-bud opacities. In the majority of patients, interventions aimed at preventing recurrent aspiration (e.g., anti-GERD therapies) led to improvement in the symptoms of DAB.

CONCLUSIONS

Young to middle-aged subjects with recognizable predisposing factors for aspiration and who report a history of recurrent pneumonia are at increased risk for DAB. Although DAB is not well recognized, certain chest CT features are characteristic of the disorder.

Survival of adults with systemic sclerosis following lung transplantation: a nationwide cohort study

OBJECTIVE

Many transplant programs are hesitant to offer lung transplantation to patients with systemic sclerosis (SSc) due to concerns about extrapulmonary involvement that might affect survival. The aim of this study was to determine whether adults with SSc have higher 1-year mortality rates after lung transplantation compared to those with interstitial lung disease (ILD) or pulmonary arterial hypertension (PAH) not due to SSc.

METHODS

Using data provided by the United Network for Organ Sharing, we performed a retrospective cohort study of 229 adults with SSc, 201 with PAH, and 3,333 with ILD who underwent lung transplantation in the US between May 4, 2005 and September 14, 2012. We examined associations between diagnosis and 1-year survival after lung transplantation using stratified Cox models adjusted for recipient, donor, and procedure factors.

RESULTS

Adults with SSc undergoing lung transplantation in the US had a multivariable-adjusted 48% relative increase in the 1-year mortality rate compared to those with non-SSc-related ILD (hazard ratio 1.48 [95% confidence interval 1.01-2.17]). However, we did not detect a difference in the risk of death at 1 year between those with SSc and those with non-SSc-related PAH (hazard ratio 0.85 [95% confidence interval 0.50-1.44]).

CONCLUSION

A diagnosis of SSc may confer an increased risk of death 1 year following lung transplantation compared to a diagnosis of ILD, but this risk is similar to that of PAH, a widely accepted indication for lung transplantation. Future work should identify modifiable risk factors that can improve transplant outcomes in this population.

[Gastro-esophageal reflux and chronic respiratory diseases]

Gastroesophageal reflux disease (GERD) frequently occurs in association with chronic respiratory diseases although the casual link is not always clear. Several pathophysiological and experimental factors are considered to support a role for GERD in respiratory disease. Conversely, respiratory diseases and bronchodilator treatment can themselves exacerbate GERD. When cough or severe asthma is being investigated, GERD does not need to be systematically looked for and a therapeutic test with proton pump inhibitors is not always recommended. pH impedance monitoring is now the reference diagnostic tool to detect non acid reflux, a form of reflux for which proton pump inhibitor treatment is ineffective. Recent data have shown a potential role of GERD in idiopathic pulmonary fibrosis and bronchiolitis obliterans following lung transplantation, leading to discussions about the place of surgery in this context. However, studies using pH impedance monitoring are still needed to better understand and manage the association between GERD and chronic respiratory diseases.

Aspiration-related pulmonary syndromes

Aspiration of foreign matter into the airways and lungs can cause a wide spectrum of pulmonary disorders with various presentations. The type of syndrome resulting from aspiration depends on the quantity and nature of the aspirated material, the chronicity, and the host responses. Aspiration is most likely to occur in subjects with a decreased level of consciousness, compromised airway defense mechanisms, dysphagia, gastroesophageal reflux, and recurrent vomiting. These aspiration-related syndromes can be categorized into airway disorders, including vocal cord dysfunction, large airway obstruction with a foreign body, bronchiectasis, bronchoconstriction, and diffuse aspiration bronchiolitis, or parenchymal disorders, including aspiration pneumonitis, aspiration pneumonia, and exogenous lipoid pneumonia. In idiopathic pulmonary fibrosis, aspiration has been implicated in disease progression and acute exacerbation. Aspiration may increase the risk of bronchiolitis obliterans syndrome in patients who have undergone a lung transplant. Accumulating evidence suggests that a causative role for aspiration is often unsuspected in patients presenting with aspiration-related pulmonary diseases; thus, many cases go undiagnosed. Herein, we discuss the broadening spectrum of these pulmonary syndromes with a focus on presenting features and diagnostic aspects.

Ventilator-associated respiratory infection following lung transplantation

The medical records of 170 adult patients who underwent lung transplantation between January 2010 and December 2012 were reviewed to assess the incidence, causative organisms, risk factors and outcomes of post-operative pneumonia and tracheobronchitis. 20 (12%) patients suffered 24 episodes of ventilator-associated pneumonia. The condition was associated with mean increases of 43 days in mechanical ventilation and of 35 days in hospital stay, and significantly higher hospital mortality (OR 9.0, 95% CI 3.2-25.1). Pseudomonas aeruginosa (eight out of 12 patients were multidrug-resistant) was the most common pathogen, followed by Enterobacteriaceae (one out of five patients produced extended-spectrum β-lactamases). Gastroparesis occurred in 55 (32%) patients and was significantly associated with pneumonia (OR 6.2, 95% CI 2.2-17.2). Ventilator-associated tracheobronchitis was associated with a mean increase of 28 days in mechanical ventilation and 30.5 days in hospital stay, but was not associated with higher mortality (OR 1.2, 95% CI 0.4-3.2). Pseudomonas aeruginosa (six out of 16 patients were multidrug resistant) was the most common pathogen, followed by Enterobacteriaceae (three out of 14 patients produced extended-spectrum β-lactamase). Patients with gastroparesis also had more episodes of ventilator-associated tracheobronchitis (40% versus 12%, p<0.001). In conclusion, ventilator-associated pneumonia following lung transplantation increased mortality. Preventing gastroparesis probably decreases the risk of pneumonia and tracheobronchitis. Multidrug-resistant bacteria frequently cause post-lung-transplantation pneumonia and tracheobronchitis.

Adaptive and innate immune responses in a rat orthotopic lung transplant model of chronic lung allograft dysfunction

Acute rejection and respiratory infections are major risk factors for chronic lung allograft dysfunction (CLAD) after lung transplantation. To shed light on the enigmatic etiology of CLAD, we test the following hypotheses using a new experimental model: (i) Alloimmune-independent pulmonary inflammation reactivates alloimmunity. (ii) Alloimmunity enhances the susceptibility of the graft toward pathogen-associated molecular patterns. Pulmonary Fischer 344 to Lewis rat allografts were treated with lipopolysaccharide (LPS), which consistently results in lesions typical for CLAD. Grafts, local lymph nodes, and spleens were harvested before (day 28) and after LPS application (days 29, 33, and 40) for real-time RT-PCR and immunohistochemistry. Mixed lymphocyte reactions were performed on day 33. Four weeks after transplantation, lung allografts displayed mononuclear infiltrates compatible with acute rejection and overexpressed most components of the toll-like receptor system. Allografts but not secondary lymphoid organs expressed increased levels of Th1-type transcription factors and cytokines. LPS induced macrophage infiltration as well as mRNA expression of pro-inflammatory cytokines and effector molecules of innate immunity. Unexpectedly, T-cell reactivity was not enhanced by LPS. We conclude that prevention of CLAD might be accomplished by local suppression of Th1 cells in stable grafts and by controlling innate immunity during alloimmune-independent pulmonary inflammation.