The importance of bronchoscopy with transbronchial biopsy and bronchoalveolar lavage in the management of lung transplant recipients

Flexible bronchoscopy in pediatric lung transplantation

Pediatric lung transplantation represents a treatment option for children with advanced lung disease or pulmonary vascular disorders who are deemed an appropriate candidate. Pediatric flexible bronchoscopy is an important and evolving field that is highly relevant in the pediatric lung transplant population. It is thus important to advance our knowledge to better understand how care for children after lung transplant can be maximally optimized using pediatric bronchoscopy. Our goals are to continually improve procedural skills when performing bronchoscopy and to decrease the complication rate while acquiring adequate samples for diagnostic evaluation. Attainment of these goals is critical since allograft assessment by bronchoscopic biopsy is required for histological diagnosis of acute cellular rejection and is an important contributor to establishing chronic lung allograft dysfunction, a common complication after lung transplant. Flexible bronchoscopy with bronchoalveolar lavage and transbronchial lung biopsy plays a key role in lung transplant graft assessment. In this article, we discuss the application of bronchoscopy in pediatric lung transplant evaluation including historical approaches, our experience, and future directions not only in bronchoscopy but also in the evolving pediatric lung transplantation field. Pediatric flexible bronchoscopy has become a vital modality for diagnosing lung transplant complications in children as well as assessing therapeutic responses. Herein, we review the value of flexible bronchoscopy in the management of children after lung transplant and discuss the application of novel techniques to improve care for this complex pediatric patient population and we provide a brief update about new diagnostic techniques applied in the growing lung transplantation field.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Personalized risk predictor for acute cellular rejection in lung transplant using soluble CD31

We evaluated the contribution of artificial intelligence in predicting the risk of acute cellular rejection (ACR) using early plasma levels of soluble CD31 (sCD31) in combination with recipient haematosis, which was measured by the ratio of arterial oxygen partial pressure to fractional oxygen inspired (PaO₂/FiO₂) and respiratory SOFA (Sequential Organ Failure Assessment) within 3 days of lung transplantation (LTx). CD31 is expressed on endothelial cells, leukocytes and platelets and acts as a "peace-maker" at the blood/vessel interface. Upon nonspecific activation, CD31 can be cleaved, released, and detected in the plasma (sCD31). The study included 40 lung transplant recipients, seven (17.5%) of whom experienced ACR. We modelled the plasma levels of sCD31 as a nonlinear dependent variable of the PaO₂/FiO₂ and respiratory SOFA over time using multivariate and multimodal models. A deep convolutional network classified the time series models of each individual associated with the risk of ACR to each individual in the cohort.

Why Cell-Free DNA Can Be a “Game Changer” for Lung Allograft Monitoring for Rejection and Infection

Purpose of Review

Although there has been improvement in short-term clinical outcomes for patients following lung transplant (LT), advances have not translated into longer-term allograft survival. Furthermore, invasive biopsies are still standard of practice for monitoring LT recipients for allograft injury. We review the relevant literature supporting the role of using plasma donor-derived cell-free DNA (dd-cfDNA) as a non-invasive biomarker for LT allograft injury surveillance and discuss future research directions.

Recent Findings

Accumulating data has demonstrated that dd-cfDNA is associated with molecular and cellular injury due to acute (cellular and antibody-mediated) rejection, chronic lung allograft dysfunction, and relevant infectious pathogens. Strong performance in distinguishing rejection and allograft injury from stable patients has set the stage for clinical trials to assess dd-cfDNA utility for surveillance of LT patients. Research investigating the potential role of dd-cfDNA methylation signatures to map injured tissue and cell-free DNA in detecting allograft injury-related pathogens is ongoing.

Summary

There is an amassed breadth of clinical data to support a role for dd-cfDNA in monitoring rejection and other forms of allograft injury. Rigorously designed, robust clinical trials that encompass the diversity in patient demographics are paramount to furthering our understanding and adoption of plasma dd-cfDNA for surveillance of lung allograft health.

Acute Rejection in the Modern Lung Transplant Era

Acute cellular rejection (ACR) remains a common complication after lung transplantation. Mortality directly related to ACR is low and most patients respond to first-line immunosuppressive treatment. However, a subset of patients may develop refractory or recurrent ACR leading to an accelerated lung function decline and ultimately chronic lung allograft dysfunction. Infectious complications associated with the intensification of immunosuppression can also negatively impact long-term survival. In this review, we summarize the most recent evidence on the mechanisms, risk factors, diagnosis, treatment, and prognosis of ACR. We specifically focus on novel, promising biomarkers which are under investigation for their potential to improve the diagnostic performance of transbronchial biopsies. Finally, for each topic, we highlight current gaps in knowledge and areas for future research.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

International Society for Heart and Lung Transplantation consensus statement for the standardization of bronchoalveolar lavage in lung transplantation

Bronchoalveolar lavage (BAL) is a key clinical and research tool in lung transplantation (LTx). However, BAL collection and processing are not standardized across LTx centers. This International Society for Heart and Lung Transplantation-supported consensus document on BAL standardization aims to clarify definitions and propose common approaches to improve clinical and research practice standards. The following 9 areas are covered: (1) bronchoscopy procedure and BAL collection, (2) sample handling, (3) sample processing for microbiology, (4) cytology, (5) research, (6) microbiome, (7) sample inventory/tracking, (8) donor bronchoscopy, and (9) pediatric considerations. This consensus document aims to harmonize clinical and research practices for BAL collection and processing in LTx. The overarching goal is to enhance standardization and multicenter collaboration within the international LTx community and enable improvement and development of new BAL-based diagnostics.

Surveillance Bronchoscopy in Lung Transplantation Recipients: A Single Center Experience Analysis

Bronchoscopy with bronchoalveolar lavage and transbronchial biopsy is the gold standard for the diagnosis of infection or acute cellular rejection in lung transplantation (LTx) recipients, but there is some controversy to perform it in asymptomatic patients. We conducted a retrospective analysis of medical reports of LTx recipients who survived in the first year after transplant during the period of August 2003 to February 2018 to evaluate the applicability of this procedure in the management of asymptomatic acute cellular rejection in our center. We assessed 1252 bronchoscopies of 247 patients during this period, and, facing the histopathological results, we defined our management that included conservative or intervention therapy. In our service the information obtained by surveillance bronchoscopy was sufficient to modify the management mainly in the first 2 surveillance bronchoscopies (second and sixth week post LTx). This effect seems to dilute after the second month, making its applicability more questionable.

Detection, classification, and management of rejection after lung transplantation

Rejection is a major complication following lung transplantation. Acute cellular rejection, lymphocytic bronchiolitis, and antibody-mediated rejection (AMR) are all risk factors for the subsequent development of chronic lung allograft dysfunction (CLAD). Acute cellular rejection and lymphocytic bronchiolitis have well defined histopathologic diagnostic criteria and grading. Diagnosis of AMR requires a multidisciplinary approach. CLAD is the major barrier to long-term survival following lung transplantation. The most common phenotype of CLAD is bronchiolitis obliterans syndrome (BOS) which is defined by a persistent obstructive decline in lung function. Restrictive allograft dysfunction (RAS) is a second phenotype of CLAD and is associated with a worse prognosis. This article will review the diagnosis, staging, clinical presentation, and treatment of acute rejection, AMR, and CLAD following lung transplantation.

Quality Improvement Initiative for Assessing Allografts after Lung Transplantation

Introduction:

The histologic evaluation of lung allografts after transbronchial biopsy (TBBx) is a key component of the clinical care of lung transplant recipients. With established guidelines on diagnosing allograft rejection, no specific recommendations exist on timeliness to reaching a diagnosis and initiating therapy. A quality improvement initiative focused on 3 key stages of achieving a prompt diagnosis of acute cellular rejection including tissue processing, interpretation, and notification to the treating transplant pulmonologist was initiated to minimize time to treatment onset.

Methods:

We completed a single-center cohort study on all surveillance and clinically indicated TBBx from September 2006 to March 2018. The rapid tissue processing, interpretation, and notification system was instituted in March 2011 with data before this date serving as baseline.

Results:

We enrolled 28 patients who underwent 210 TBBx (1 excluded due to unknown notification date). Thirty-eight TBBx were included at baseline before implementation of the rapid tissue processing and communication system; 171 were included after implementation. Median time to notification following the change was 0 days (interquartile range, 0–1) compared with 1 day (interquartile range, 1–1) before the change (P < 0.001). After the change, same-day notification increased, with 110 (64%) TBBx resulting in same-day notification compared with 0 before (P < 0.001). We initiated treatment of acute cellular rejection on the day of diagnosis for the entire cohort.

Conclusions:

This quality improvement initiative resulted in more efficient analysis of TBBx of allografts in lung transplant recipients and faster communication of results to the clinical team.

Impact of SLCO1B3 polymorphisms on clinical outcomes in lung allograft recipients receiving mycophenolic acid

Single-nucleotide polymorphisms (SNPs) in genes involved in mycophenolic acid (MPA) metabolism have been shown to contribute to variable MPA exposure, but their clinical effects are unclear. We aimed to determine if SNPs in key genes in MPA metabolism affect outcomes after lung transplantation. We performed a retrospective cohort study of 275 lung transplant recipients, 228 receiving mycophenolic acid and a control group of 47 receiving azathioprine. Six SNPs known to regulate MPA exposure from the SLCO, UGT and MRP2 families were genotyped. Primary outcome was 1-year survival. Secondary outcomes were 3-year survival, nonminimal (≥A2 or B2) acute rejection, and chronic lung allograft dysfunction (CLAD). Statistical analyses included time-to-event Kaplan-Meier with log-rank test and Cox regression modeling. We found that SLCO1B3 SNPs rs4149117 and rs7311358 were associated with decreased 1-year survival [rs7311358 HR 7.76 (1.37-44.04), p = 0.021; rs4149117 HR 7.28 (1.27-41.78), p = 0.026], increased risk for nonminimal acute rejection [rs4149117 TT334/T334G: OR 2.01 (1.06-3.81), p = 0.031; rs7311358 GG699/G699A: OR 2.18 (1.13-4.21) p = 0.019] and lower survival through 3 years for MPA patients but not for azathioprine patients. MPA carriers of either SLCO1B3 SNP had shorter survival after CLAD diagnosis (rs4149117 p = 0.048, rs7311358 p = 0.023). For the MPA patients, Cox regression modeling demonstrated that both SNPs remained independent risk factors for death. We conclude that hypofunctional SNPs in the SLCO1B3 gene are associated with an increased risk for acute rejection and allograft failure in lung transplant recipients treated with MPA.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Sequential broncho-alveolar lavages reflect distinct pulmonary compartments: clinical and research implications in lung transplantation

Background

Bronchoalveolar lavage (BAL) has proven to be very useful to monitor the lung allograft after transplantation. In addition to allowing detection of infections, multiple BAL analytes have been proposed as potential biomarkers of lung allograft rejection or dysfunction. However, BAL collection is not well standardized and differences in BAL collection represent an important source of variation. We hypothesized that there are systematic differences between sequential BALs that are relevant to BAL analysis.

Methods

As part of 126 consecutive bronchoscopies in lung transplant recipients, two sequential BALs (BAL1 and BAL2) were performed in one location during each bronchoscopy by instilling and suctioning 50 ml of normal saline twice into separate containers. Cell concentration, viability and differentials, Surfactant Protein-D (SP-D), Club Cell Secretory Protein (CCSP), and levels of CXCL10, IL-10, CCL2, CCL5, VEGF-C, RAGE, CXCL9, CXCL1, IL-17A, IL-21, PDGF, and GCSF were compared between BAL1 and BAL2.

Results

Total cell concentration did not differ between BAL1 and BAL2; however, compared to BAL2, BAL1 had more dead cells, epithelial cells, neutrophils, and higher concentrations of airway epithelium-derived CCSP and inflammatory markers. BAL2 had a higher concentration of SP-D compared to BAL1.

Conclusion

In this study performed in lung transplant recipients, we show that sequential BALs represent different lung compartments and have distinct compositions. BAL1 represents the airway compartment with more epithelial cells, neutrophils, and epithelium-derived CCSP. Conversely, BAL2 samples preferentially the distal bronchoalveolar space with greater cell viability and higher SP-D. Our findings illustrate how the method of BAL collection can influence analyte concentrations and further emphasize the need for a standardized approach in translational research involving BAL samples.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0786-z) contains supplementary material, which is available to authorized users.

Prevention of chronic rejection after lung transplantation

Long-term survival after lung transplantation (LTx) is limited by chronic rejection (CR). Therapeutic strategies for CR have been largely unsuccessful, making prevention of CR an important and challenging therapeutic approach. In the current review, we will discuss current clinical evidence regarding prevention of CR after LTx.

Acute rejection

Despite induction immunosuppression and the use of aggressive maintenance immunosuppressive regimens, acute allograft rejection following lung transplantation is still a problem with important diagnostic and therapeutic challenges. As well as causing early graft loss and mortality, acute rejection also initiates the chronic alloimmune responses and airway-centred inflammation that predispose to bronchiolitis obliterans syndrome (BOS), also known as chronic lung allograft dysfunction (CLAD), which is a major source of morbidity and mortality after lung transplantation. Cellular responses to human leukocyte antigens (HLAs) on the allograft have traditionally been considered the main mechanism of acute rejection, but the influence of humoral immunity is increasingly recognised. As with other several other solid organ transplants, antibody-mediated rejection (AMR) is now a well-accepted and distinct clinical entity in lung transplantation. While acute cellular rejection (ACR) has defined histopathological criteria, transbronchial biopsy is less useful in AMR and its diagnosis is complicated by challenges in the measurement of antibodies directed against donor HLA, and a determination of their significance. Increasing awareness of the importance of non-HLA antigens further clouds this issue. Here, we review the pathophysiology, diagnosis, clinical presentation and treatment of ACR and AMR in lung transplantation, and discuss future potential biomarkers of both processes that may forward our understanding of these conditions.

Acute Rejection and Antibody-Mediated Rejection in Lung Transplantation

Despite advances in immunosuppression over the past 25 years, acute cellular rejection remains a common complication early after lung transplantation. Although acute cellular rejection has often not resulted in clinical signs or symptoms of allograft dysfunction, it has been widely recognized as a strong independent risk factor for the development of chronic rejection, emphasizing its clinical significance. In recent years, the role of humoral immunity in lung rejection has been increasingly appreciated, and antibody-mediated rejection is now recognized as a form of rejection that may result in allograft failure.

Critical Care Aspects of Lung Transplant Patients

Major strides have been made in lung transplantation during the 1990s and it has become an established treatment option for patients with advanced lung disease. Due to improvements in organ preservation, surgical techniques, postoperative intensive care, and immunosuppression, the risk of perioperative and early mortality (less than 3 months after transplantation) has declined [1]. The transplant recipient now has a greater chance of realizing the benefits of the long and arduous waiting period.

Despite these improvements, suboptimal long-term outcomes continue to be shaped by issues such as opportunistic infections and chronic rejection. Because of the wider use of lung transplantation and the longer life span of recipients, intensivists and ancillary intensive care unit (ICU) staff should be well versed with the care of lung transplant recipients.

In this clinical review, issues related to organ donation will be briefly mentioned. The remaining focus will be on the critical care aspects of lung transplant recipients in the posttransplant period, particularly ICU management of frequently encountered conditions. First, the groups of patients undergoing transplantation and the types of procedures performed will be outlined. Specific issues directly related to the allograft, including early graft dysfunction from ischemia-reperfusion injury, airway anastomotic complications, and infections in the setting of immunosuppression will be emphasized. Finally nonpulmonary aspects of posttransplant care and key pharmacologic points in the ICU will be covered.

Bronchoscopic procedures and lung biopsies in pediatric lung transplant recipients

Bronchoscopy remains a pivotal diagnostic and therapeutic intervention in pediatric patients undergoing lung transplantation (LTx). Whether performed as part of a surveillance protocol or if clinically indicated, fibre-optic bronchoscopy allows direct visualization of the transplanted allograft, and in particular, an assessment of the patency of the bronchial anastomosis (or tracheal anastomosis following heart-lung transplantation). Additionally, bronchoscopy facilitates differentiation of infective processes from rejection episodes through collection and subsequent assessment of bronchoalveolar lavage (BAL) and transbronchial biopsy (TBBx) samples. Indeed, the diagnostic criteria for the grading of acute cellular rejection is dependent upon the histopathological assessment of biopsy samples collected at the time of bronchoscopy. Typically, performed in an out-patient setting, bronchoscopy is generally a safe procedure, although complications related to hemorrhage and pneumothorax are occasionally seen. Airway complications, including stenosis, malacia, and dehiscence are diagnosed at bronchoscopy, and subsequent management including balloon dilatation, laser therapy and stent insertion can also be performed bronchoscopically. Finally, bronchoscopy has been and continues to be an important research tool allowing a better understanding of the immuno-biology of the lung allograft through the collection and analysis of collected BAL and TBBx samples. Whilst new investigational tools continue to evolve, the simple visualization and collection of samples within the lung allograft by bronchoscopy remains the gold standard in the evaluation of the lung allograft. This review describes the use and experience of bronchoscopy following lung transplantation in the pediatric setting.

An international ISHLT/ATS/ERS clinical practice guideline: diagnosis and management of bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is a major complication of lung transplantation that is associated with poor survival. The International Society for Heart and Lung Transplantation, American Thoracic Society, and European Respiratory Society convened a committee of international experts to describe and/or provide recommendations for 1) the definition of BOS, 2) the risk factors for developing BOS, 3) the diagnosis of BOS, and 4) the management and prevention of BOS. A pragmatic evidence synthesis was performed to identify all unique citations related to BOS published from 1980 through to March, 2013. The expert committee discussed the available research evidence upon which the updated definition of BOS, identified risk factors and recommendations are based. The committee followed the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) approach to develop specific clinical recommendations. The term BOS should be used to describe a delayed allograft dysfunction with persistent decline in forced expiratory volume in 1 s that is not caused by other known and potentially reversible causes of post-transplant loss of lung function. The committee formulated specific recommendations about the use of systemic corticosteroids, cyclosporine, tacrolimus, azithromycin and about re-transplantation in patients with suspected and confirmed BOS. The diagnosis of BOS requires the careful exclusion of other post-transplant complications that can cause delayed lung allograft dysfunction, and several risk factors have been identified that have a significant association with the onset of BOS. Currently available therapies have not been proven to result in significant benefit in the prevention or treatment of BOS. Adequately designed and executed randomised controlled trials that properly measure and report all patient-important outcomes are needed to identify optimal therapies for established BOS and effective strategies for its prevention.

Pediatric lung transplantation: promise being realized

PURPOSE OF REVIEW

Lung transplantation for infants and children is an accepted but rarely exercised option for the treatment of end-stage lung disease, with outcomes equivalent to those for adults. However, widespread misconceptions regarding pediatric outcomes often confound timely and appropriate referral to specialty centers. We present the updated information for primary pediatricians to utilize when counseling families with children confronted by progressive end-stage pulmonary or cardiovascular disease.

RECENT FINDINGS

We provide general guidelines to consider for referral, and discuss allocation of organs in children, information regarding standard treatment protocols, and survival outcomes.

SUMMARY

Lung transplantation is a worthwhile treatment option to consider in children with end-stage lung disease. The treatment is complex, but lung transplant provides substantial survival benefit and markedly improved quality of life for children and their families. This timely review provides comprehensive information for pediatricians who are considering options for treatment of children with end-stage lung disease.

Safety and efficacy of outpatient bronchoscopy in lung transplant recipients - a single centre analysis of 3,197 procedures

BACKGROUND

Bronchoscopy represents an important diagnostic and therapeutic tool in the management of lung transplant (LTx) recipients. Outpatient bronchoscopy reduces health costs and may improve quality of life amongst these patients. This retrospective study assessed the safety and efficacy of outpatient bronchoscopy including trans-bronchial biopsy.

METHODS

All outpatient bronchoscopies performed on lung transplant recipients between 1 August 2008 and 31 January 2011 were reviewed. Sample quality, duration and complications were recorded. Cost analysis was performed from local trust financial data.

RESULTS

A total of 3,197 bronchoscopies were performed on 571 LTx recipients under topical anaesthesia. Fourteen percent of examinations required intravenous sedation. In 79.8% of examinations no complications were observed. Most complications were minor (17.9%) including cough (5.3%) and minimal bleeding after trans-bronchial biopsy (7.8%). Major complications (2.3%) were pneumothorax, severe bleeding and severe desaturation. No attributable deaths were recorded during the observation period. Quality of examination based on bronchoalveolar lavage recovery median (>50%) and biopsy results was adequate at 75% and 77.4%, respectively. Independent risk factors associated with complication were long-term oxygen therapy, sedation before examination, balloon dilatation and transbronchial biopsy. After excluding high-risk procedures annual savings per patient (2.2 bronchoscopies per year) were 2140€.

CONCLUSIONS

Outpatient bronchoscopy after LTx is safe. The low complication rate could be attributed to withholding of intravenous sedation. Furthermore, it reduces health community costs.

Significance of new lung infiltrates in outpatients after lung and heart-lung transplantation

Background

Infection and rejection represent major complications following lung transplantation and are often associated with pulmonary infiltrates. The differential diagnosis of these infiltrates depends on their timing after transplantation. The aim of this study was to characterize lung transplant recipients (LTR) presenting with new pulmonary infiltrates.

Methods

A retrospective analysis of all LTR and heart–lung transplant recipients attending outpatient follow‐up at our institution between September 1, 2006 and October 14, 2011 was performed. All patients presenting with new pulmonary infiltrates on chest x‐ray who underwent bronchoscopy were included.

Results

A total of 913 patients accounted for 13,156 attendances, with 3,912 bronchoscopies being performed. Seventy‐eight patients (9%) exhibited new pulmonary infiltrates and proceeded to bronchoscopy. Infiltrates occurred at a median 15 (interquartile range [IQR] 5–39) months after transplantation. Forty‐eight patients (62%) were male, and median patient age was 47 (IQR 29–57) years. Subsequent investigation revealed pneumonia to be the underlying cause in 63 patients (81%). In the remaining patients, chronic lung allograft dysfunction (CLAD) was responsible in 6 (8%), acute rejection in 5 (6%), and toxic pneumonitis in 4 (5%) patients. Overall 1‐year survival in LTR presenting with new infiltrates was 97%, compared with 96% for all LTR attending our Outpatient Department.

Conclusions

New pulmonary infiltrates occurring after the first month in LTR are most likely due to infection. Through prompt diagnosis and treatment, early mortality appears unaffected. Late mortality remains attributable to CLAD.

Surveillance transbronchial biopsies in infant lung and heart-lung transplant recipients

There are limited published data on surveillance TBB for the identification of allograft rejection in infants after lung or heart-lung transplantation. We performed a retrospective review of children under one yr of age who underwent lung or heart-lung transplant at our institution. Since 2005, four infants were transplanted (three heart-lung and one lung). The mean age (±s.d.) at the time of transplant was 5.5 ± 2.4 (range 3-8) months. A total of 16 surveillance TBB procedures were completed in both inpatient and outpatient settings, with a range of 3-7 performed per patient. A minimum of five acceptable tissue pieces with expanded alveoli were obtained in 81% (13/16) of TBB procedures and a minimum of three pieces in 88% (14/16). There was no evidence of acute allograft rejection in 88% (14/16) of TBB procedures. One TBB procedure yielded two tissue specimens demonstrating A2 acute allograft rejection. One TBB procedure failed to yield tissue with sufficient alveoli. Additionally, B-grade assessment identified B0 in 50% (8/16), B1R in 12% (2/16), and BX (ungradeable or insufficient sample) in 38% (6/16) of biopsy procedures, respectively. In conclusion, TBB may be safely performed as an inpatient and outpatient procedure in infant lung and heart-lung transplant recipients and may provide adequate tissue for detecting acute allograft rejection and small airway inflammation.

Combined heart-lung transplantation: a perspective on the past and the future

During the last 20 years, there has been a shift away from combined heart-lung transplantation (HLT) in favor of bilateral lung transplantation. This paradigm shift allowed for the donor heart to be transplanted to another patient. However, HLT remains to be the definitive surgical treatment for certain congenital heart disorders and Eisenmenger's syndrome. With a growing population of adult patients with congenital heart disease, there remains a need for HLT. This article provides a perspective on the past and the future of HLT.

Current status of lung transplantation

Lung transplantation is a well-established treatment option for selected patients with end-stage lung disease, leading to improved survival and improved quality of life. The last 20 years have seen a steady growth in number of lung transplantation procedures performed worldwide. The increase in clinical activity has been associated with tremendous progress in the understanding of cellular and molecular processes that limit both short- and long-term outcomes. This review gives a comprehensive overview of the current status of lung transplantation for the referring physician. It demonstrates that careful selection of potential recipients, optimisation of their condition prior to transplant, use of carefully assessed donor organs, excellent surgery and meticulous long-term follow-up are all essential ingredients in determining a successful outcome.

Pulmonary complications of lung transplantation

Lung transplantation is an effective treatment option for select patients with a variety of end-stage lung diseases. Although transplant can significantly improve the quality of life and prolong survival, a myriad of pulmonary complications may result in significant morbidity and limit long-term survival. The recognition and early treatment of these complications is important for optimizing outcomes. This article provides an overview and update of the pulmonary complications that may be commonly encountered by pulmonologists caring for these patients.

Optimizing post-transplant outcomes in lung transplantation

Lung transplant recipients are at risk of numerous complications, which range from early events, such as primary graft dysfunction, to late events, including opportunistic infection or graft loss caused by chronic rejection. Although lung transplantation is often the only therapeutic option that can improve quality of life and prolong survival for many forms of end-stage lung disease, survival following lung transplantation is significantly worse than survival following transplantation of other solid organs. Carefully choosing potential recipients for listing, maximizing the likelihood that donor organs will function well following implantation, appropriate use of immunosuppressive agents to prevent allograft rejection, prophylactic or pre-emptive strategies to prevent allograft infection and appropriate surveillance to detect significant complications are key to maximizing the likelihood of prolonged graft and patient survival while avoiding significant complications following lung transplantation. Post-transplant outcomes will be optimized by a team approach to comprehensive management of the lung transplantation recipient combined with vigilant surveillance to detect complications in a timely fashion.

Acute rejection and humoral sensitization in lung transplant recipients

Despite the recent introduction of many improved immunosuppressive agents for use in transplantation, acute rejection affects up to 55% of lung transplant recipients within the first year after transplant. Acute lung allograft rejection is defined as perivascular or peribronchiolar mononuclear inflammation. Although histopathologic signs of rejection often resolve with treatment, the frequency and severity of acute rejections represent the most important risk factor for the subsequent development of bronchiolitis obliterans syndrome (BOS), a condition of progressive airflow obstruction that limits survival to only 50% at 5 years after lung transplantation. Recent evidence demonstrates that peribronchiolar mononuclear inflammation (also known as lymphocytic bronchiolitis) or even a single episode of minimal perivascular inflammation significantly increase the risk for BOS. We comprehensively review the clinical presentation, diagnosis, histopathologic features, and mechanisms of acute cellular lung rejection. In addition, we consider emerging evidence that humoral rejection occurs in lung transplantation, characterized by local complement activation or the presence of antibody to donor human leukocyte antigens (HLA). We discuss in detail methods for HLA antibody detection as well as the clinical relevance, the mechanisms, and the pathologic hallmarks of humoral injury. Treatment options for cellular rejection include high-dose methylprednisolone, antithymocyte globulin, or alemtuzumab. Treatment options for humoral rejection include intravenous immunoglobulin, plasmapheresis, or rituximab. A greater mechanistic understanding of cellular and humoral forms of rejection and their role in the pathogenesis of BOS is critical in developing therapies that extend long-term survival after lung transplantation.

Overview of lung transplantation

Although significant gains have been made in improving lung function and survival in cystic fibrosis (CF), ultimately respiratory failure is the leading cause of mortality in these patients. For CF patients with end stage lung disease, lung transplantation is an option for treatment. The field of lung transplantation has progressed markedly in the last 20 years. Nonetheless it remains a technically complex and challenging procedure, and patients are at risk for numerous short term and long term complications. Potential transplant recipients must be physically and psychologically prepared for the arduous process involved in lung transplantation. This article will review the history of lung transplantation, indications for transplantation, surgical techniques, and complications of transplantation.

Lung

Experiments with animals in the 1940 and 1950s demonstrated that lung transplantation was technically possible [33]. In 1963, Dr. James Hardy performed the first human lung transplantation. The recipient survived 18 days, ultimately succumbing to renal failure and malnutrition [58]. From 1963 through 1978, multiple attempts at lung transplantation failed because of rejection and complications at the bronchial anastomosis. In the 1980s, improvements in immunosuppression, especially the introduction of cyclosporin A, and enhanced surgical techniques led to renewed interest in organ transplantation. In 1981, a 45-year-old-woman received the first successful heart–lung transplantation for idiopathic pulmonary arterial hypertension (IPAH) [106]. She survived 5 years after the procedure. Two years later the first successful single lung transplantation for idiopathic pulmonary fibrosis (IPF) [128] was reported, and in 1986 the first double lung transplantation for emphysema [25] was performed.

Intensive care management of the patient with cystic fibrosis

Cystic fibrosis was previously thought to be a disease of childhood. With a better understanding of this condition along with improvements in therapy, patients with cystic fibrosis are now living well into adulthood. The aim of this article is to familiarize the intensive care unit physician with cystic fibrosis care, to discuss complications associated with cystic fibrosis specifically related to the intensive care unit, and to detail the current recommendations for the clinical management of the patient with cystic fibrosis. With advancing disease, the most severely affected organs are the lungs. Obstruction, infection, and inflammation contribute to the decline of pulmonary function, ultimately leading to death. Some patients may be eligible for lung transplantation, but choosing wisely will affect posttransplant survival. Because other organs are affected by the genetic defect and associated treatments, serious complications related to the liver, pancreas, intestines, and kidneys must be considered by the intensivist faced with a patient with cystic fibrosis. As practitioners, the fact that not all patients will survive and help our patients and families gracefully through the end-of-life process should be accepted.

Obliterative Bronchiolitis

Obliterative bronchiolitis (OB) is a condition characterized by inflammation and fibrosis of the bronchiolar walls resulting in narrowing or obliteration of the bronchiolar lumen. The most common causes are childhood lower respiratory tract infection, hematopoietic stem cell or lung and heart-lung transplantation, and toxic fume inhalation. The most frequent clinical manifestations are progressive dyspnea and dry cough. Pulmonary function tests demonstrate airflow obstruction and air trapping. Radiographic manifestations include reduction of the peripheral vascular markings, increased lung lucency, and overinflation. The chest radiograph, however, is often normal. High-resolution CT is currently the imaging modality of choice in the assessment of patients with suspected or proven OB. The characteristic findings on high-resolution CT consist of areas of decreased attenuation and vascularity (mosaic perfusion pattern) on inspiratory scans and air trapping on expiratory scans. Other CT findings of OB include bronchiectasis and bronchiolectasis, bronchial wall thickening, small centrilobular nodules, and three-in-bud opacities. Recent studies suggest that hyperpolarized ³He-enhanced magnetic resonance imaging may allow earlier recognition of obstructive airway disease and therefore may be useful in the diagnosis and follow-up of patients with OB.

Posttransplant monitoring of pediatric lung transplant recipients

PURPOSE OF REVIEW

This article reviews current trends in pediatric lung posttransplant management, reveals pitfalls that exist, and introduces additional parameters that may have an impact on long-term survival.

RECENT FINDINGS

A number of parameters are monitored after transplantation to prevent or identify early complications related to lung transplantation in hope of reducing morbidity and mortality. These include routine laboratory studies, imaging, and monitoring of drug levels and lung function. Drug monitoring allows individualization of a patient's immunosuppressive therapy; however, drug levels alone may not reflect the patient's immune status. ImmuKnow is a general immune-monitoring assay that may help guide therapy. Two major complications are rejection and infection, and bronchoscopy is used to differentiate these two entities. Silent rejection may occur and increase the chance of developing bronchiolitis obliterans; therefore, many centers perform surveillance bronchoscopies. Recently, de-novo anti-histocompatibility locus antigen antibodies and gastroesophageal reflux have been associated with poor outcomes, and many centers are monitoring these entities as part of care following lung transplant.

SUMMARY

There has been little improvement in long-term outcomes of lung transplantation. Current monitoring methods are utilized to maintain or improve outcomes and recently additional monitoring parameters have been identified which hopefully will improve long-term outcomes.

Allograft Rejection After Lung Transplantation

Lung transplantation has become an accepted therapy for selected patients with advanced lung disease. One of the main limitations to successful lung transplantation is rejection of the transplanted organ. This article discusses the clinical presentation, treatment, and prevention of hyperacute, acute, and chronic rejection in the lung transplant recipient.

The Utility of Cytopathology Testing in Lung Transplant Recipients

BACKGROUND

Lung transplant recipients routinely undergo bronchoscopy, during which bronchoalveolar lavage (BAL) fluid and transbronchial biopsies are usually obtained. These specimens are typically sent for microbiology, histopathology and cytopathology testing. Cytopathology testing is expensive, and its diagnostic value is questionable. We hypothesized that cytopathology specimens have no additional diagnostic yield beyond that of microbiology and histopathology testing in the routine care of our lung transplant patients.

METHODS

We reviewed all bronchoscopies performed on a cohort of patients who underwent lung transplantation between February 1999 and August 2002 at our institution. Demographic data, immunosuppressive therapy and the incidence of opportunistic infections in this cohort of 65 patients were reviewed. To ascertain the diagnostic value of cytopathology testing, microbiology and histopathology results from bronchoalveolar lavage and transbronchial biopsy tests were compared with cytopathology results.

RESULTS

Three hundred sixty-six bronchoscopies were reviewed. Microbiologic and histopathology identified 51 cytomegalovirus-, 157 fungus- and 13 mycobacteria-positive specimens as well as respiratory syncitial virus, influenza A and B, enterovirus, actinomyces, Nocardia and mycoplasma. Cytopathology of BAL fluid identified only 3 cytomegalovirus- and 13 fungus-positive specimens. The only unique diagnoses made by cytopathology were 1 case of Aspergillus and 1 unidentifiable fungal element.

CONCLUSIONS

We conclude that routine cytopathology testing has little additive diagnostic value in bronchoscopic specimens from lung transplant recipients. Cytopathology results did not alter patient management in any of our 366 cases. Centers should consider discontinuing routine use of cytopathology testing of BAL fluid for surveillance or clinically indicated bronchoscopy, because the yield of this expensive test is extremely low in the setting of lung transplantation.

Pneumonia in the solid organ transplant patient

As the field of solid organ transplantation has grown, so has the importance of infectious complications in this select group of patients. Chronic immunosuppression compromises the natural host defenses that typically prevent lower respiratory tract infections and makes the solid organ transplant recipient especially susceptible to pneumonia. Evaluation of pneumonia in this population differs owing to the potential for opportunistic infections. Lung transplant recipients are particularly susceptible to pneumonia and pose unique diagnostic dilemmas. An understanding of the time line for the different key pathogens after transplantation aids the initial evaluation and management.

Bronchoscopy in the diagnosis and surveillance of respiratory infections in lung and heart-lung transplant recipients

Fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) and transbronchial biopsies (TBB) is a widely used method to detect respiratory infections and to differentiate them from other postoperative complications in lung transplant (LTX) recipients, but the usefulness of surveillance FOBs is not yet established. The aim of this study was to evaluate the usefulness of FOB in the diagnosis and surveillance of infections in LTX recipients. We reviewed all the consecutive 609 FOBs performed on 40 lung or heart-LTX recipients between February 1994 and November 2002. The overall diagnostic yield was 115/190 (61%) and 43/282 (15%) for clinically indicated and surveillance FOBs respectively (P < 0.001). Infection was established by bronchoscopic samples in 96/190 (50.5.%) of the clinically indicated FOBs and 34/282 (12.1%) of the surveillance FOBs (P < 0.001). The diagnostic yield of the clinically indicated FOBs was highest (72%) from 1 to 6 months post-transplant (P = 0.04). Pneumocystis carinii was detected in 23 (4.9%) of the bronchoscopic specimens and 15 (65%) of the P. carinii infections were detected during adequate chemoprophylaxis. To conclude, in LTX recipients clinically indicated FOB has a good diagnostic yield in detecting infections and other postoperative complications, whereas the information received from surveillance FOB has remained less significant. With current prophylaxis and screening strategies FOB is still required to detect P. carinii infections.

Yield of surveillance bronchoscopy for acute rejection and lymphocytic bronchitis/bronchiolitis after lung transplantation

BACKGROUND

Better understanding of the timing and pattern of surveillance bronchoscopy findings after lung transplantation could influence the timing and frequency of surveillance bronchoscopy. We present our surveillance bronchoscopy experience and test the hypothesis that patients not encountering early acute rejection or lymphocytic bronchitis/bronchiolitis are less likely to have subsequent occult occurrences in the 1st year after lung transplantation.

METHODS

We conducted a retrospective study of 204 patients who underword transplantation between 1996 and 2000. Based on contemporary biopsy-specimen grading in the first 100 days, we formed 2 groups: No Early Rejection and Early Rejection. We compared subsequent yields of surveillance bronchoscopy and the incidence of acute rejection or of lymphocytic bronchitis/bronchiolitis.

RESULTS

We reviewed 645 biopsies taken from 204 recipients during the first 100 days to classify patients into a No Early Rejection Group (n=67) or an Early Rejection Group (n=137). Yield of surveillance bronchoscopy for acute rejection or lymphocytic bronchitis/bronchiolitis was 31% with the greatest yield during the first 30 days (45%), and then decreasing to 26% (p <0.001). After Day 100, 71% of occult acute rejection episodes involved minimal (A1) lesions. Yield of surveillance bronchoscopy after Day 100 was 20% in the No Early Rejection Group and was 27% in the Early Rejection Group (p=0.22). Incidence of acute rejection or lymphocytic bronchitis/bronchiolitis after Day 100 was 41% in the No Early Rejection Group and was 50% in the Early Rejection Group (p=0.17).

CONCLUSION

Surveillance bronchoscopy detects occult acute rejection or lymphocytic bronchitis/bronchiolitis in approximately one-third of biopsy specimens during the 1st year, with the majority of late abnormalities being minimal (A1) rejection. The absence of acute rejection or lymphocytic bronchitis/bronchiolitis during the first 100 days does not predict freedom from such events in the remainder of the 1st year.

Are symptom reports useful for differentiating between acute rejection and pulmonary infection after lung transplantation?

BACKGROUND

Prompt treatment of acute rejection and pulmonary infection reduces morbidity and mortality in lung transplant recipients. Symptoms, spirometry, and bronchoscopy are used to detect these complications. Of these, symptom reporting is the least invasive, yet has received little critical examination.

OBJECTIVE

To examine the potential for using reports of symptoms, such as cough and shortness of breath, to recognize clinically significant acute rejection and pulmonary infection after lung transplantation.

METHODS

Symptoms reported during routine follow-up visits were compared between lung transplant recipients (LTR) with clinically significant acute rejection (grade >or= A2) and those without (grade A0 or A1) and between LTR with rejection (grade >or= A2) and those with pulmonary infection.

RESULTS

LTR with rejection (grade >or= A2) reported more symptoms (P < .01) than did those without (grade A0, A1); however, the magnitude of difference was minimal. LTR with clinically significant acute rejection (grade >or= A2) reported symptoms at a rate comparable with those having pulmonary infection.

CONCLUSIONS

Although symptoms may alert LTR to changes in their condition, no symptoms (respiratory, general, or activities of daily living [ADL]) differentiate between grades of rejection or pulmonary infection.

Bronchoalveolar lavage fluid characteristics in acute and chronic lung transplant rejection

BACKGROUND

The detection of graft rejection by bronchoalveolar lavage remains controversial.

METHODS

To assess the value of bronchoalveolar lavage fluid in acute and chronic rejection after lung transplantation we analyzed bronchoalveolar lavage fluid cellular differential characteristics, lymphocyte sub-types and interleukin-6 (IL-6) and interleukin-8 (IL-8) cytokine levels in patients with exclusively either acute rejection (n = 37) or bronchiolitis obliterans (BO; n = 48). Both groups were compared with a control group of lung transplantation patients without rejection or infection, matched for the time the lavage was performed after lung transplantation.

RESULTS

The bronchiolitis obliterans group showed marked neutrophilia, high IL-8 and higher CD4(+)CD25(+) and CD8(+)CD45(+) bronchoalveolar lavage fluid levels when compared with their stable controls. When using a cut-off point of >3% neutrophils in the lavage, the sensitivity for BO is 87.0%, the specificity 77.6%. The sensitivity of IL-8 for BO when using a cut-off point of >71.4 pg/ml is 74.5%, the specificity 83.3%. Bronchoalveolar lavage fluid in acute rejection was characterized by marked lymphocytosis, but showed no difference when compared with stable controls in any of the lymphocyte sub-types studied. When using a cut-off point of <==1% lymphocytes in the lavage, the sensitivity for acute rejection (AR) is 40.4%, the specificity 95.6%. The marked neutrophilia, high IL-8 cytokine level and more activated lymphocyte population in bronchiolitis obliterans may indicate ongoing local allograft rejection.

CONCLUSIONS

In the present study we were not able to show any difference in lymphocyte sub-types when comparing acute rejection and control subjects. Cellular and soluble parameters in bronchoalveolar lavage fluid appear useful for diagnosing bronchiolitis obliterans.

The use of multiple transbronchial biopsies as the standard approach to evaluate lung allograft rejection

Flexible bronchoscopy with transbronchial biopsy (TBB) is routinely performed in adult and pediatric lung transplant recipients. The clinical signs and symptoms of acute cellular rejection (ACR) are often identical to those of infection. TBB is a fairly sensitive and specific tool in which to diagnose ACR and can be performed safely in children of all ages. The utility of TBB is unquestioned during periods of worsening clinical symptoms. The utility of TBB for routine surveillance of the allograft remains unproven. The data suggests that during the first 4-6 months post-transplant there is a high incidence of clinically silent ACR. The significance of subclinical rejection in lung transplantation is unknown. Randomized, controlled trials are required to determine if multiple surveillance TBB, can impact the incidence of obliterative bronchiolitis.

Role of Transbronchial Biopsies in Pediatric Lung Diseases

STUDY OBJECTIVE

To evaluate the role of transbronchial biopsies (TBBs) in pediatric lung diseases.

DESIGN AND METHODS

We reviewed the records of TBBs performed in pediatric patients at the University of Florida between July 1996 and August 2003. The sample adequacy, diagnostic utility, and procedural complications of the two types of bronchoscopy apparatuses used to collect the samples were assessed and compared.

PATIENTS

A total of 429 TBB procedures were performed in 46 patients (age range, 2 months to 21 years) who had received a heart-lung or lung transplant and in 38 non-lung transplant patients (age range, 2 weeks to 18 years). For 86 procedures, the pediatric bronchoscope and forceps that fit in a 1.2-mm channel were used, and a small adult bronchoscope and 2.0-mm forceps were used for the remaining procedures.

RESULTS

Adequate tissue samples were obtained in 85% of the procedures using a pediatric bronchoscope and in 97% using an adult bronchoscope. In the non-lung transplant patients, the biopsy findings were considered to be diagnostic in 58% of all procedures (adult bronchoscope, 64%; and pediatric bronchoscope, 50%), contributory in 21%, and noncontributory in 21%. In the lung transplant patients, treatable acute cellular rejection was diagnosed in 24% of the surveillance TBBs and in 47% of the TBBs performed as a result of clinical symptoms. Complications included five pneumothoraces and five episodes of excessive bleeding requiring the discontinuation of the procedure in three of the cases.

CONCLUSIONS

Adequate lung tissue for histologic diagnosis can be obtained safely and effectively from pediatric patients of all ages via flexible bronchoscopy with TBB. The performance of bronchoscopy should be considered based on clinical indications, rather than on the age or size of the patient, when a tissue diagnosis is needed. When feasible, the use of an adult bronchoscope is preferable due to the higher diagnostic yield.

Critical care aspects of lung transplantation

Lung transplantation currently is the preferred treatment option for a variety of end-stage pulmonary diseases. Remarkable progress has occurred through refinements in technique and improved understanding of transplant immunology and microbiology. As a result, recipients are surviving longer after their transplant. Despite improvements in short- and intermediate-term survival, long-term success with lung transplantation remains limited by chronic allograft rejection, also known as bronchiolitis obliterans syndrome. Despite its long-term limitations, lung transplantation remains the only hope for many with end-stage pulmonary disease, and during the past 20 years, it has become increasingly accepted and used. As a result, clinicians working in an intensive care unit (ICU) are more likely to be exposed to these patients both in the immediate postoperative period as well as throughout their remaining lives. It is thus important that the ICU team have a working knowledge of the common complications, when these complications are most likely to occur, and how best to treat them when they do arise. The main focus of this review is to address the variety of potential graft and life-threatening problems that may occur in lung transplant recipients. Because the ICU is also the most common setting where a potential donor is identified, donor issues will briefly be addressed.

Pulmonary complications of solid organ and hematopoietic stem cell transplantation

The ability to successfully transplant solid organs and hematopoietic stem cells represents one of the landmark medical achievements of the twentieth century. Solid organ transplantation has emerged as the standard of care for select patients with severe vital organ dysfunction and hematopoietic stem cell transplantation has become an important treatment option for patients with a wide spectrum of nonmalignant and malignant hematologic disorders, genetic disorders, and solid tumors. Although advances in surgical techniques, immunosuppressive management, and prophylaxis and treatment of infectious diseases have made long-term survival an achievable goal, transplant recipients remain at high risk for developing a myriad of serious and often life-threatening complications. Paramount among these are pulmonary complications, which arise as a consequence of the immunosuppressed status of the recipient as well as from such factors as the initial surgical insult of organ transplantation, the chemotherapy and radiation conditioning regimens that precede hematopoietic stem cell transplantation, and alloimmune mechanisms mediating host-versus-graft and graft-versus-host responses. As the population of transplant recipients continues to grow and as their care progressively shifts from the university hospital to the community setting, knowledge of the pulmonary complications of transplantation is increasingly germane to the contemporary practice of pulmonary medicine.