Lung transplantation

Survival of primary and repeat lung transplantation in the United States

BACKGROUND

This study was undertaken to compare survival between primary and repeat lung transplant recipients and to identify survival predictors after repeat lung transplantation.

METHODS

Data for 10,846 primary and 354 repeat lung transplant patients were extracted from the United Network for Organ Sharing registry. Propensity score matching was used to examine balance in the distribution of potential observed confounders and to match the sample in terms of the probability of repeat lung transplantation given pretransplant characteristics alone. Matching based on the propensity score was used to compare survival between the primary and repeat lung transplant groups. A Cox regression model was used to identify risk factors for death in the cohort of patients receiving lung transplant.

RESULTS

Considerable bias between the primary and repeat lung transplant groups was found in the sample. Patients with high propensity scores tended to carry high-risk profiles. Propensity score matching revealed incomplete overlap of covariate distributions between primary and repeat transplant groups. For those subjects who could be matched for the set of potential confounding variables, no difference in survival time was observed between primary and repeat lung transplant patients. Functional status and serum creatinine level were the two clinically important risk factors for predicting the survival of repeat transplant patients.

CONCLUSIONS

The current study revealed that direct comparison of the survival of primary and repeat lung transplant patients is biased by nonoverlap in the distribution of potential confounders. Using propensity score matching we adjusted for this bias and found that there was no significant difference in survival between first and second transplants.

[Surgical treatment of chronic obstructive pulmonary disease]

Treatment of advanced emphysema is not limited to medical management. Surgical options can also be envisioned for some cases, and physicians must know about them. A bullectomy may be considered for giant bullae, defined by a volume greater than a third of a hemithorax. This option must be discussed even in cases of advanced obstructive disease. Lung volume reduction surgery is useful for emphysema that is heterogeneously distributed but without individual giant bullae. A large-scale controlled study helped to identify its indications and results. The third possible surgical option is lung transplantation. It offers the greatest functional benefits but also involves considerable risks. One of the key points is therefore to define the optimal moment in a patient's life when this option should be discussed. Recent guidelines developed by a panel of international experts provide clinicians with the criteria for considering transplantation.

Lung transplant outcomes in white and African American recipients: special focus on acute and chronic rejection

BACKGROUND

The effects of lung transplant recipient race on post-transplant outcomes have not been adequately evaluated. This cohort study seeks to determine the characteristics of African American lung transplant recipients and the effects of African American race on post-transplant outcomes, particularly acute and chronic rejection, compared with white recipients, at a single center.

METHODS

There were 485 first-time lung transplantations (431 white, 47 African American, 5 Hispanic and 2 Asian recipients) performed at the University of Pennsylvania between 1991 and 2006. All white and African American recipients were compared based on pre-transplant diagnoses and post-transplant survival. The cohort from 1998 to 2006 (239 white and 25 African American recipients) was also compared based on acute rejection score (ARS) and development of bronchiolitis obliterans syndrome (BOS).

RESULTS

Chronic obstructive pulmonary disease was the most common diagnosis leading to lung transplantation in both groups, but sarcoidosis was a much more common indication in African American recipients (white, 1%; African American, 28%; p < 0.001). Survival was similar in the two groups (white vs African American groups: 1 month, 90.0% vs 87.2%; 1 year, 74.9% vs 74.5%; 5 years, 52.3% vs 50.5%, respectively; p = 0.84). Freedom from BOS at 3 years (white, 60.3%; African American, 62.8%; p = 0.30) and ARS per biopsy (white, 0.83 +/- 0.82; African American, 0.63 +/- 0.77; p = 0.31) were similar in both groups.

CONCLUSIONS

White and African American patients seek lung transplantation for different diseases, but post-transplant outcomes were found to be similar. Larger, multi-center studies are needed to confirm these results.

Anti-type V collagen humoral immunity in lung transplant primary graft dysfunction

Primary graft dysfunction (PGD) is a major complication following lung transplantation. We reported that anti-type V collagen (col(V)) T cell immunity was strongly associated with PGD. However, the role of preformed anti-col(V) Abs and their potential target in PGD are unknown. Col(V) immune serum, purified IgG or B cells from col(V) immune rats were transferred to WKY rat lung isograft recipients followed by assessments of lung pathology, cytokines, and PaO(2)/FiO(2), an index of lung dysfunction in PGD. Immune serum, purified IgG, and B cells all induced pathology consistent with PGD within 4 days posttransfer; up-regulated IFN-gamma, TNF-alpha, and IL-1beta locally; and induced significant reductions in PaO(2)/FiO(2). Depleting anti-col(V) Abs before transfer demonstrated that IgG2c was a major subtype mediating injury. Confocal microscopy revealed strong apical col(V) expression on lung epithelial, but not endothelial cells; which was consistent with the ability of col(V) immune serum to induce complement-dependent cytotoxicity only in the epithelial cells. Examination of plasma from patients with or without PGD revealed that higher levels of preformed anti-col(V) Abs were strongly associated with PGD development. This study demonstrates a major role for anti-col(V) humoral immunity in PGD, and identifies the airway epithelium as a target in PGD.

Perfil do doador de pulmão disponibilizado no estado de São Paulo, Brasil, em 2006

OBJETIVO: Analisar a taxa de aproveitamento de pulmões disponibilizados em São Paulo no ano de 2006, bem como caracterizar o perfil dos doadores de pulmão deste período. MÉTODOS: Estudo retrospectivo de 497 prontuários de doadores de pulmão, no período de janeiro a dezembro de 2006. RESULTADOS: Não houve oferta de doação de pulmões para transplante em 149 (30%) dos prontuários analisados, sendo excluídos do estudo. A idade média dos 348 doadores eleitos para o estudo foi de 37,4 ± 16,1 anos, e 56,9% deles eram do sexo masculino. As principais causas da morte cerebral dos doadores foram: acidente vascular cerebral (40,5%); trauma cranioencefálico (34,2%); e hemorragia subaracnóidea (10,9%). A grande maioria dos doadores recebia drogas vasoativas (90,5%), sendo que 13,5% haviam apresentado parada cárdio-respiratória. Do ponto de vista infeccioso, o leucograma médio foi de 15.008 ± 6.467 células/mm³, 67,8% recebiam antibioticoterapia e 26,1% apresentavam infecção pulmonar. Quase 40% dos doadores apresentavam alterações radiográficas. Apenas 4,9% dos doadores foram aceitos, representando 28 pulmões (taxa de aproveitamento de órgãos de 4%). Os motivos de recusa foram: alteração gasométrica (30,1%); infecção (23,7%); e distância (10,9%). CONCLUSÕES: A taxa de aproveitamento de pulmões em nosso meio é baixa quando comparada às taxas médias de aproveitamento mundial. Além disso, mais de 50% das recusas deveram-se à gasometria arterial inadequada e infecção pulmonar. Aliar melhor cuidado ao potencial doador à menor rigidez nos critérios de seleção poderia aumentar a utilização dos órgãos doados.

Coping and quality of life in patients awaiting lung transplantation

OBJECTIVE

Patients with end-stage lung disease (ESLD) experience significant decrements in quality of life (QOL). Although coping strategies are related to QOL in patients with ESLD, the extent to which specific native lung disease moderates this relationship is unknown.

METHODS

We investigated the relationship between coping, native lung disease, and QOL among 187 patients awaiting lung transplantation, including 139 patients with chronic obstructive pulmonary disease (COPD) and 48 with cystic fibrosis (CF). Participants completed a psychosocial battery assessing psychological QOL, physical QOL, and coping strategies.

RESULTS

For both COPD and CF patients, higher levels of Active Coping (P< .0001) and lower levels of Disengagement (P< .0001) were associated with better psychological QOL. For physical QOL, we observed a Native Disease x Coping interaction (P=.01) such that Active Coping was associated with better physical QOL in patients with COPD but not in patients with CF.

CONCLUSIONS

The relationship between coping and QOL may vary as a function of native lung disease. Patients' native disease may need to be considered in order to develop effective interventions to help patients cope successfully with ESLD.

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.

A critical review of candidacy for orthotopic liver transplantation in alcoholic liver disease

The majority of candidates with end-stage alcoholic liver disease (ESALD) in the United States who are eligible for referral for liver transplantation (LT) are not being referred. There is a lack of firm consensus for the duration of abstinence from alcohol as well as what constitutes good psychosocial criteria for listing for LT. Evidence shows that the general public and the practicing physicians outside the transplant community perceive that patients with a history of alcohol abuse will make poor transplant candidates. However, physicians in the transplant community perceive selected patients with ESALD as good candidates. When considering patients for listing for LT, 3 months of alcohol abstinence may be more ideal than 6 months. Patients with a lack of social support, active smoking, psychotic or personality disorders, or a pattern of nonadherence should be listed only with reservation. Those who have a diagnosis of alcohol abuse as opposed to alcohol dependence may make better transplant candidates. Patients who have regular appointments with a psychiatrist or psychologist in addictions treatment training also seem to do more favorably.

Survival after bilateral versus single lung transplantation for patients with chronic obstructive pulmonary disease: a retrospective analysis of registry data

BACKGROUND

Both single and bilateral lung transplantation are recognised options for patients who have end-stage chronic obstructive pulmonary disease (COPD); however, which procedure leads to longer survival remains unclear. We aimed to compare survival after each procedure by analysing data from the registry of the International Society for Heart and Lung Transplantation.

METHODS

We analysed data for 9883 patients with COPD, 3525 (35.7%) of whom underwent bilateral lung transplantation, and 6358 (64.3%) single lung transplantation, between 1987 and 2006. We accounted for possible selection bias with analysis of covariance, propensity-score risk adjustment, and propensity-based matching.

FINDINGS

Median survival after either type of lung transplantation for patients with COPD was 5.0 years (95% CI 4.8-5.2). Survival for patients who had lung transplantation before 1998 was 4.5 years (4.3-4.8), compared with 5.3 years (5.0-5.5) for those who had it after 1998 (p<0.0001). The proportion of patients who had bilateral lung transplantation increased from 101/467 (21.6%) in 1993 to 345/614 (56.2%) in 2006. Median survival time after bilateral lung transplantation was longer than that after single lung transplantation: 6.41 years (6.02-6.88) versus 4.59 years (4.41-4.76) (p<0.0001). Pretransplant characteristics of patients who had single and bilateral lung transplantation differed, but whichever method was used to adjust for baseline differences, bilateral lung transplantation was associated with longer survival than was single lung transplantation; the hazard ratio ranged from 0.83 (0.78-0.92) for analysis of covariance to 0.89 (0.80-0.97) for propensity-based matching. However, bilateral lung transplantation had little benefit compared with single lung transplantation for patients who were 60 years and older (HR 0.95; 0.81-1.13).

INTERPRETATION

Bilateral lung transplantation leads to longer survival than single lung transplantation in patients with COPD, especially those who are younger than 60 years.

Tiotropium bromide

Therapy with bronchodilators forms the pharmacologic foundation of the treatment of patients with COPD. Bronchodilators can significantly lessen dyspnea, increase airflow, improve quality of life, and enhance exercise performance. While bronchodilators decrease airway resistance and lessen dynamic hyperinflation in patients with COPD, they have not been shown to alter the rate of decline in FEV₁ over time, or improve patient survival. Fairly recently, a long-acting, once-daily anticholinergic medication, tiotropium bromide, has been developed which may improve symptom management in COPD patients. This paper reviews anticholinergic pharmacologic therapy for patients with COPD focusing on tiotropium bromide, and discusses treatment strategies based on disease stage. It is important to recognize that while bronchodilators improve symptoms, a multimodality treatment approach including respiratory and rehabilitative therapy, nutrition services, psychosocial counseling, and surgical care, is often necessary for the best possible care of patients with COPD.

Determination of interleukin-6 in lung transplantation: association with primary graft dysfunction

INTRODUCTION AND OBJECTIVE

Primary graft dysfunction (PGD) secondary to damage caused by ischemia/reperfusion is responsible for significant morbidity. It constitutes the main cause of early death following implantation. Our objective was to verify the association between PGD and activation of the inflammatory cascade by measuring interleukin-6 (IL-6) in the blood and the bronchoalveolar lavage (BAL) of the recipient.

MATERIALS AND METHODS

The 31 patients, including 22 bipulmonary and 9 unipulmonary cases, had severe PGD (ISHLT grade II) defined by: (1) radiographic infiltrates during the first 72 hours after transplantation, (2) PO2/FiO2 ratio <200 in the first 72 hours after the operation, and (3) no other cause of dysfunction. BAL and peripheral arterial blood samples were extracted prior to implantation (baseline level) and at 12, 24, and 48 hours after reperfusion. Samples were frozen to -80 degrees C until determination of IL-6 using an immunoassay technique (ELISA).

RESULTS

In the 31 transplants (100%), there were elevated IL-6 contents in the BAL and blood compared with the baseline level (P < .0001). Among 11 patients with severe PGD (38.70%) In the BAL samples the concentration of IL-6 was significantly elevated (P < .05) compared with patients without PGD (P < .031). These finding were also observed in blood (P < .016) obtained at 12 hours. The analyses at 24 and 48 hours showed higher levels of IL-6 in the PGD group, although they were not significant.

CONCLUSIONS

There was a significant elevation of IL-6 in blood and BAL during the first few hours after reperfusion of the graft, which was directly related to the development of PGD.

[Pneumonias and immunosuppression]

Pneumonias are common, life threatening complications in immunodeficient patients. A rapid, targeted diagnosis and therapy are decisive for the course of the disease. The etiological spectrum is substantially broader than for immunocompetent patients. Important indications are provided by the type and intensity of the immunosuppression, gaps in the prophylactic concept and particular exposures. For diagnostic planning, high resolution computed tomogram of the thorax is necessary. The standard method for isolating the pathogen is flexible bronchoscopy with bronchoalveolar lavage. Indications for invasive bioptic measures depend on the individual situation, the expected spectrum of pathogens as well as risk factors and adverse effects. Non-invasive antigen and PCR tests complement the diagnostic spectrum, especially for difficult to cultivate pathogens such as fungi and Herpes viruses. The selection of the initial, targeted antimicrobial therapy is based on guidelines. The treatment should be followed after obtaining the relevant microbiological data.

A new murine model for bronchiolitis obliterans post-bone marrow transplant

RATIONALE

Bronchiolitis obliterans (BO) is a major problem in lung transplantation and is also part of the spectrum of late-onset pulmonary complications that can occur after hematopoietic stem cell transplant. Better mouse models are needed to study the onset of this disease so that therapeutic interventions can be developed.

OBJECTIVES

Our goal was to develop a BO mouse model.

METHODS

Recipients were lethally conditioned and given a rescue dose of T-cell-depleted, allogeneic bone marrow (BM) supplemented with a sublethal dose of allogeneic T cells.

MEASUREMENTS AND MAIN RESULTS

At 2 months post-BM transplant, the lungs had extensive perivascular and peribronchiolar inflammation consisting of CD4(+) T cells, CD8(+) T cells, B cells, macrophages, neutrophils, and fibroblasts. In contrast to the acute model, histology showed airway obstruction consistent with BO. Epithelial cells of airways in the early stages of occlusion exhibited changes in expression of cytokeratins. Although the lung had severe allogeneic BM transplant-mediated disease, there was only mild to moderate graft-versus-host disease in liver, colon, skin, and spleen. High wet/dry weight ratios and elevated hydroxyproline were seen, consistent with pulmonary edema and fibrosis. Mice with BO exhibited high airway resistance and low compliance. Increases in many inflammatory mediators in the lungs of mice that develop BO were seen early post-transplant and not later at the time of BO.

CONCLUSIONS

This new mouse model will be useful for the study of BO associated with late post-hematopoietic stem cell transplant onset and chronic graft-versus-host disease, which also leads to poor outcome in the lung transplant setting.

Evaluation of the Oxygenation Ratio as Long-Term Prognostic Marker After Lung Transplantation

OBJECTIVE

We hypothesized that the arterial blood gas oxygen tension/fraction of inspired oxygen ratio (PaO2/FiO2) would prove to be useful as a mortality marker after lung transplantation (LT). The aims of this study were to define the prevalence of various ranges of PaO2/FiO2 during the first 24 hours after LT and to evaluate which measurement using the PaO2/FiO2 best correlates with mortality.

METHODS

A retrospective study was performed that included all patients who underwent LT from 1997 to 2005. We collected PaO2/FiO2 ratios at 0, 12, and 24 hours after admission to the intensive care unit (ICU). We classified the 132 patients in 5 groups, based on PaO2/FiO2 (Group 1, PaO2/FiO2 <100; Group 2, PaO2/FiO2 100-199; Group 3, PaO2/FiO2 200-299; Group 4, PaO2/FiO2 300-399; Group 5, PaO2/FiO2 >or=400). The correlation between PaO2/FiO2 and mortality was studied using Cox regression.

RESULTS

Cox regression analysis showed that PaO2/FiO2 at 0 and 12 hours after admission to the ICU were not useful mortality markers. However, the PaO2/FiO2 at 24 hours after admission to the ICU was a useful long-term prognostic marker. PaO2/FiO2 >100 (groups 2, 3, 4, and 5) at 24 hours was significantly associated with less mortality when a lower PaO2/FiO2 was the reference (hazard Ratio: 0.08, 0.02, 0.05, and 0.02, respectively). On multivariate analysis PaO2/FiO2 >or=100 (groups 2, 3, 4, and 5) at 24 hours was significantly associated with less mortality when a lower PaO2/FiO2 was the reference (hazard ratio: 0.07, 0.003, 0.01, and 0.005, respectively).

CONCLUSIONS

A value of PaO2/FiO2 >100 mm Hg 24 hours after admission to the ICU is associated with a lower mortality.

Canadian Thoracic Society recommendations for management of chronic obstructive pulmonary disease - 2007 update

Chronic obstructive pulmonary disease (COPD) is a major respiratory illness in Canada that is both preventable and treatable. Our understanding of the pathophysiology of this complex condition continues to grow and our ability to offer effective treatment to those who suffer from it has improved considerably. The purpose of the present educational initiative of the Canadian Thoracic Society (CTS) is to provide up to date information on new developments in the field so that patients with this condition will receive optimal care that is firmly based on scientific evidence. Since the previous CTS management recommendations were published in 2003, a wealth of new scientific information has become available. The implications of this new knowledge with respect to optimal clinical care have been carefully considered by the CTS Panel and the conclusions are presented in the current document. Highlights of this update include new epidemiological information on mortality and prevalence of COPD, which charts its emergence as a major health problem for women; a new section on common comorbidities in COPD; an increased emphasis on the meaningful benefits of combined pharmacological and nonpharmacological therapies; and a new discussion on the prevention of acute exacerbations. A revised stratification system for severity of airway obstruction is proposed, together with other suggestions on how best to clinically evaluate individual patients with this complex disease. The results of the largest randomized clinical trial ever undertaken in COPD have recently been published, enabling the Panel to make evidence-based recommendations on the role of modern pharmacotherapy. The Panel hopes that these new practice guidelines, which reflect a rigorous analysis of the recent literature, will assist caregivers in the diagnosis and management of this common condition.

Human cytomegalovirus and human immunodeficiency virus type-1 co-infection in human cervical tissue

Human cytomegalovirus (HCMV) and human immunodeficiency virus type-1 (HIV-1) infect the female genital tract. A human cervical explant model was developed to study single and dual infection by these viruses in the genital compartment. An HCMV strain expressing green fluorescent protein, and two clinical HCMV strains produced peak viral DNA copies at 14 to 21 days post-infection. Peak levels of HIV-1(Ba-L) p24 antigen occurred at 7 days post-infection. HIV-1(Ba-L) appeared to enhance HCMV in co-infected tissues. Singly and dually infected explants produced increased levels of cytokines IL-6, IL-8, and GRO-alpha in culture supernatants. Immunohistochemical and flow cytometric analysis showed HCMV infection of leukocytes with the phenotype CD45+/CD1a+/CD14+/HLA-DR+ but not stromal or endothelial cells. Cells expressing both GFP and HIV-1 p24 antigen were detected in co-infected tissues. The cervical explants provide an ex vivo human model for examining mechanisms of virus-virus interaction and pathogenesis in clinically relevant tissue.

Lung transplantation and pulmonary hypertension

The presence of pulmonary hypertension affects lung transplantation in multiple ways, from patient selection, transplant risks, type of transplant, intraoperative management, to transplant outcome. A working knowledge of natural disease progression, the latest medical treatment options, and transplant outcome is critical in patient selection, and a good understanding of the transplant process, including the new transplant allocation system, is important for physicians involved in the care of patients with pulmonary arterial hypertension. The complexity of these factors underscores the importance of good communication between referring physicians and transplant centers.

Impact of preservation solution on the extent of blood-air barrier damage and edema formation in experimental lung transplantation

A major aim in lung transplantation is to prevent the loss of structural integrity due to ischemia and reperfusion (I/R) injury. Preservation solutions protect the lung against I/R injury to a variable extent. We compared the influence of two extracellular-type preservation solutions (Perfadex, or PX, and Celsior, or CE) on the morphological alterations induced by I/R. Pigs were randomly assigned to sham (n = 4), PX (n = 5), or CE (n = 2) group. After flush perfusion with PX or CE, donor lungs were excised and stored for 27 hr at 4 degrees C. The left donor lung was implanted into the recipient, reperfused for 6 hr, and, afterward, prepared for light and electron microscopy. Intra-alveolar, septal, and peribronchovascular edema as well as the integrity of the blood-air barrier were determined stereologically. Intra-alveolar edema was more pronounced in CE (219.80 +/- 207.55 ml) than in PX (31.46 +/- 15.75 ml). Peribronchovascular (sham: 13.20 +/- 4.99 ml; PX: 15.57 +/- 5.53 ml; CE: 31.56 +/- 5.78 ml) and septal edema (thickness of alveolar septal interstitium, sham: 98 +/- 33 nm; PX: 84 +/- 8 nm; CE: 249 +/- 85 nm) were only found in CE. The blood-air barrier was similarly well preserved in sham and PX but showed larger areas of swollen and fragmented epithelium or endothelium in CE. The present study shows that Perfadex effectively prevents intra-alveolar, septal, and peribronchovascular edema formation as well as injury of the blood-air barrier during I/R. Celsior was not effective in preserving the lung from morphological I/R injury.

Surgical therapies for pulmonary arterial hypertension

Surgical therapies for the treatment of pulmonary arterial hypertension typically are reserved for patients who are deemed to be refractory to medical therapy and have evidence of progressive right-sided heart failure. Atrial septostomy, a primarily palliative procedure, may stave off hemodynamic collapse from right-sided heart failure long enough to permit a more definitive surgical treatment such as lung or combined heart-lung transplantation. This article discusses indications for and results of atrial septostomy and lung and heart-lung transplantation in patients who have pulmonary arterial hypertension.

Special considerations for patients with cystic fibrosis undergoing lung transplantation

This article reviews lung transplantation in patients with cystic fibrosis (CF). Lung transplantation is commonly utilized for patients with end-stage CF. There are several characteristics of CF that present unique challenges before and after lung transplantation. There is new information available that can be utilized to predict outcomes in patients with end-stage CF, and therefore can help in decisions of referral and listing for lung transplantation. The new lung allocation score, which allocates organs to patients who are on the lung transplant waiting list in the United States, presents new challenges and opportunities for patients with end-stage CF. In addition, the effect of the presence of microbiological flora prior to lung transplantation has been better linked to outcomes after lung transplantation. It is now known that, other than those patients harboring Burkholderia cepacia in their lungs before transplantation, most CF patients can undergo transplantation successfully. Nutrition remains an important issue among CF patients, and diabetes is a common problem after lung transplantation. In contrast, liver disease does not usually present major problems but, if it is severe, can necessitate liver and lung transplantation. Mechanical ventilation prior to transplantation might not be an absolute contraindication for CF patients. CF lung transplant recipients have good outcomes after lung transplantation compared with those of other lung transplant recipients. Quality of life is dramatically improved. However, they are still prone to common complications that all lung transplant recipients are prone to, including primary graft dysfunction, acute and chronic rejection, a variety of infections and malignancies, and renal failure.

Pulsatile Blood Flow and Oxygen Transport Past a Circular Cylinder

The fundamental study of blood flow past a circular cylinder filled with an oxygen source is investigated as a building block for an artificial lung. The Casson constitutive equation is used to describe the shear-thinning and yield stress properties of blood. The presence of hemoglobin is also considered. Far from the cylinder, a pulsatile blood flow in the x direction is prescribed, represented by a time periodic (sinusoidal) component superimposed on a steady velocity. The dimensionless parameters of interest for the characterization of the flow and transport are the steady Reynolds number (Re), Womersley parameter (α), pulsation amplitude (A), and the Schmidt number (Sc). The Hill equation is used to describe the saturation curve of hemoglobin with oxygen. Two different feed-gas mixtures were considered: pure O2 and air. The flow and concentration fields were computed for Re=5, 10, and 40, 0≤A≤0.75, α=0.25, 0.4, and Schmidt number, Sc=1000. The Casson fluid properties result in reduced recirculations (when present) downstream of the cylinder as compared to a Newtonian fluid. These vortices oscillate in size and strength as A and α are varied. Hemoglobin enhances mass transport and is especially important for an air feed which is dominated by oxyhemoglobin dispersion near the cylinder. For a pure O2 feed, oxygen transport in the plasma dominates near the cylinder. Maximum oxygen transport is achieved by operating near steady flow (small A) for both feed-gas mixtures. The time averaged Sherwood number, Sh̿, is found to be largely influenced by the steady Reynolds number, increasing as Re increases and decreasing with A. Little change is observed with varying α for the ranges investigated. The effect of pulsatility on Sh̿ is greater at larger Re. Increasing Re aids transport, but yields a higher cylinder drag force and shear stresses on the cylinder surface which are potentially undesirable.

Early growth response gene-1 promotes airway allograft rejection

Chronic airway rejection, characterized by lymphocytic bronchitis, epithelial cell damage, and obliterative bronchiolitis (OB), limits long-term survival after lung transplantation. The transcription factor early growth response gene-1 (Egr-1) induces diverse inflammatory mediators, some involved in OB pathogenesis. An orthotopic mouse tracheal transplant model was used to determine whether Egr-1 promotes development of airway allograft rejection. Significantly higher Egr-1 mRNA levels were seen in allografts (3.2-fold increase vs. isografts, P = 0.012). Allografts revealed thickening of epithelial and subepithelial airway layers (51 +/- 4% luminal encroachment for allografts vs. 20 +/- 3% for isografts, P < 0.0001) marked by significant lymphocytic infiltration. Absence of the Egr-1 gene in donor (but not recipient) tissue resulted in significant reduction in luminal narrowing (34 +/- 4%, P = 0.0001) with corresponding diminution of T cell infiltration. Egr-1 null allografts exhibited a striking reduction in inducible nitric oxide synthase (iNOS) expression. Effector cytokines previously implicated in OB pathogenesis with known Egr-1 promoter motifs (IL-1beta and JE/monocyte chemoattractant protein-1) were reduced in Egr-1 null allografts. These data suggest a paradigm wherein local induction of Egr-1 in tracheal allografts drives expression of inflammatory mediators responsible for lymphocyte recruitment and tissue destruction characteristic of airway rejection.

Evidence for tissue-resident mesenchymal stem cells in human adult lung from studies of transplanted allografts

The origin and turnover of connective tissue cells in adult human organs, including the lung, are not well understood. Here, studies of cells derived from human lung allografts demonstrate the presence of a multipotent mesenchymal cell population, which is locally resident in the human adult lung and has extended life span in vivo. Examination of plastic-adherent cell populations in bronchoalveolar lavage samples obtained from 76 human lung transplant recipients revealed clonal proliferation of fibroblast-like cells in 62% (106 of 172) of samples. Immunophenotyping of these isolated cells demonstrated expression of vimentin and prolyl-4-hydroxylase, indicating a mesenchymal phenotype. Multiparametric flow cytometric analyses revealed expression of cell-surface proteins, CD73, CD90, and CD105, commonly found on mesenchymal stem cells (MSCs). Hematopoietic lineage markers CD14, CD34, and CD45 were absent. Multipotency of these cells was demonstrated by their capacity to differentiate into adipocytes, chondrocytes, and osteocytes. Cytogenetic analysis of cells from 7 sex-mismatched lung transplant recipients harvested up to 11 years after transplant revealed that 97.2% +/- 2.1% expressed the sex genotype of the donor. The presence of MSCs of donor sex identity in lung allografts even years after transplantation provides what we believe to be the first evidence for connective tissue cell progenitors that reside locally within a postnatal, nonhematopoietic organ.

Human and murine obliterative bronchiolitis in transplant

Obliterative bronchiolitis is a devastating illness that limits the long-term success of lung transplantation. Its high prevalence and overall poor response to current therapeutic measures demands further research to elucidate pathogenic mechanisms. Toward this goal, there is a role for animal models to study the mechanisms of obliterative bronchiolitis, such as the murine heterotopic tracheal allograft model. This review compares the tracheal allograft model to human obliterative bronchiolitis pathology and highlights the important mechanisms of airway rejection described using this model. Although certain limitations exist, the pursuit of proof-of-concept studies in this model, as well as other animal models, can provide the basis for genetic and cellular translational human studies directed toward post-transplant obliterative bronchiolitis pathogenesis. To meet these challenges, we call for the establishment of a National Institutes of Health-supported Lung Transplant Network to better orchestrate translational research efforts in obliterative bronchiolitis pathogenesis and treatment, and to advance the field of lung transplantation.

IL-13 is pivotal in the fibro-obliterative process of bronchiolitis obliterans syndrome

Acute allograft rejection is considered to be a predominately type 1 immune mediated response to the donor alloantigen. However, the type 2 immune mediated response has been implicated in multiple fibroproliferative diseases. Based on the fibro-obliterative lesion found during bronchiolitis obliterans syndrome (BOS), we hypothesized that the type 2 immune mediated response is involved in chronic lung allograft rejection. Specifically, whereas acute rejection is, in part, a type 1 immune response, chronic rejection is, in part, a type 2 immune response. We found the type 2 cytokine, IL-13, to be elevated and biologically active in human bronchoalveolar lavage fluid during BOS. Translational studies using a murine model of BOS demonstrated increased expression of IL-13 and its receptors that paralleled fibro-obliteration. In addition, in vivo neutralization of IL-13 reduced airway allograft matrix deposition and murine BOS, by a mechanism that was independent of IL-4. Furthermore, using IL-13Ralpha2(-/-) mice, we found increased fibro-obliteration. Moreover, anti-IL-13 therapy in combination with cyclosporin A had profound effects on reducing murine BOS. This supports the notion that IL-13 biological axis plays an important role during the pathogenesis of BOS independent of the IL-4 biological axis.

Air Trapping: Comparison of Standard-Dose and Simulated Low-Dose Thin-Section CT Techniques

PURPOSE

To prospectively investigate the effect of radiation dose reduction on the visual quantification of air trapping at expiratory thin-section computed tomography (CT).

MATERIALS AND METHODS

In this ethical committee-approved study, 27 lung transplant recipients (12 women, 15 men; mean age, 54 years +/- 2 [standard error of the mean]) underwent expiratory thin-section CT at 140 kVp and 80 mAs (effective). All patients gave written informed consent. Dose reduction corresponding to 60, 40, and 20 mAs (effective) was simulated. The extent of air trapping in both original and dose-reduced studies was scored by three independent readers. The effects of tube current-time product, reader, reading session, and body mass index on average air trapping scores were assessed with analysis of variance. Agreements between and within observers were assessed with a weighted kappa statistic. Subjective scores for diagnostic confidence were attributed (3 = high, 2 = medium, 1 = low), and their means were calculated for each tube current-time product value.

RESULTS

No significant effect on average air trapping scores as a result of tube current-time product (P = .222), reader (P = .217), reading session (P = .705), or body mass index (P = .505) could be detected. At 80 mAs, agreement between readers was excellent; agreement decreased to good or moderate at lower tube current settings. Agreement within readers decreased with a decrease in dose but remained good even at 20 mAs. Confidence also decreased, with mean scores decreasing from 2.33 +/- 0.73 (standard deviation) to 1.04 +/- 0.19 when dose decreased.

CONCLUSION

At 140 kVp, the tube current-time product can be reduced from 80 to 20 mAs without impairing the visual quantification of air trapping at expiratory thin-section CT and with acceptable decreases in agreement between and within readers and in reader confidence.

Recipient vascular endothelial growth factor serum levels predict primary lung graft dysfunction

Primary graft dysfunction (PGD) is a severe complication in lung transplantation. Therapeutic strategies are limited and there exist no predictive markers for PGD. To investigate whether vascular endothelial growth factor (VEGF) that regulates vascular permeability could predict PGD, pretransplant VEGF serum concentrations were measured in 150 lung transplant patients and 12 controls by ELISA. PGD was scored from 0 to 3 using chest radiographs and PaO(2)/FiO(2) ratios according to the International Society for Heart and Lung Transplantation guidelines. The mean graft ischemia time was 5 h 47 min and the donors' PaO(2)/FiO(2) ratios were >300. PGD grades 0-3 occurred in 23%, 44%, 21%, and 11% of patients, respectively. Pre-operative VEGF serum concentrations were significantly higher in PGD grade 3 (p < 0.0001) versus grade 0-2 and controls. VEGF concentrations significantly predicted PGD grade 3 versus 0-2 in logistic regression analysis (p < 0.0001) and receiver operating analysis (AUC = 0.778). At a cut-off level of > or =650 pg/mL VEGF had 86% sensitivity and 62% specificity to identify PGD grade 3 versus 0-2. Pre-operative VEGF serum concentrations could identify lung transplant recipients with high PGD risk.

Clinical and radiologic factors associated with pulmonary nodule etiology in organ transplant recipients

Identifying clinical and radiographic factors that are associated with a specific etiology of pulmonary nodules (PNs) in solid-organ transplant (SOT) recipients might be helpful in guiding empiric therapy. Multivariable logistic regression was used to assess the relationship of clinical and radiographic variables to the etiology of PN in a retrospectively identified cohort of SOT recipients at a single transplant center. PNs in 55 SOT recipients (lung 15%, heart 22%, liver 42%, kidney 18% or kidney/pancreas 5%) were diagnosed at a mean of 1061 days post-transplant and were infectious in 31 of 55 (56%) (bacterial 22%, fungal 33%, viral 2%) and noninfectious in 24 of 55 (44%) [post-transplant lymphoproliferative disorder (PTLD) 25%, carcinoma 18%]. Radiographic 'consolidation' was independently associated with an infectious etiology (OR, 20.2, p < 0.01). Epstein-Barr virus seronegativity and lung transplant were each associated with PTLD (OR, 21.7, p < 0.01) and (OR, 36.6, p < 0.001), respectively. Diagnosis less than 90 days post-transplant was associated with Aspergillus infection (OR, 12.9, p = 0.007). Specific clinical and radiographic features are associated with specific etiologies of PNs in SOT recipients and might be useful for guiding empiric therapy while awaiting results of definitive diagnostic studies.

Liver transplant in cystic fibrosis: a poll among European centers. A study from the European Liver Transplant Registry

Liver Transplant (LTx) has been rarely performed in cystic fibrosis (CF) patients and indications and outcomes are not well defined. A questionnaire was sent to all European CF and LTx centers to collect data on CF transplanted patients. We obtained information regarding 57 CF patients. LTx has been performed prevalently in males and in pediatric age. The main complication of cirrhosis was portal hypertension with hypersplenism. In the majority of cases the decision to transplant was based on the contemporary presence of various factors. Post-LTx survival was high and comparable with that expected for more common pediatric LTx indications. Poor respiratory function was the main risk factor for early death. In the short-term, respiratory function significantly improved after LTx. LTx is the appropriate treatment for patients with advanced CF-related liver disease and preserved pulmonary function (Forced Expiratory Volume at 1 s, FEV(1) >50%). This poll reveals that most European liver centers perform LTx prior to the development of end-stage liver disease or overt pulmonary or other clinical decompensation.

Sequential gene expression profiling in lung transplant recipients with chronic rejection

STUDY OBJECTIVES

Chronic allograft rejection is the leading cause of morbidity and mortality for long-term survivors of lung transplantation. Previous studies have implicated only isolated genes in the development of chronic rejection and have not examined multiple pathways in an individual concurrently. Using microarray technology, we identified and compared gene expression profiling in lung transplant recipients with and without chronic rejection, and follow sequential expression of genes differentially expressed between the two groups.

DESIGN

Prospective, cohort study.

SETTING

Single lung transplant center.

PATIENTS OR PARTICIPANTS

Eleven transplant recipients with chronic rejection were matched with 9 control transplant recipients.

INTERVENTIONS

All recipients underwent surveillance bronchoscopies at predetermined times to rule out infection and/or acute rejection. Gene expression profiling was obtained from hybridizing BAL fluid cell RNA to a 96-gene microarray.

MEASUREMENTS AND RESULTS

Fifteen genes were found to be significantly differentially expressed between the two patient groups, and they are involved in inflammatory, fibrotic, and apoptotic pathways. Temporal expression of the significant genes demonstrated a change in their levels at the onset of chronic rejection, with normalization to prerejection levels as rejection continued.

CONCLUSIONS

We conclude that microarray technology is valuable in studying the mechanism of chronic lung rejection, and the expression of genes in multiple pathways is elevated in patients with chronic lung rejection.

Association of protein C and type 1 plasminogen activator inhibitor with primary graft dysfunction

BACKGROUND

Acute lung injury is characterized by hypercoagulability and impaired fibrinolysis. We hypothesized that lower protein C and higher type 1 plasminogen activator inhibitor (PAI-1) levels in plasma would be associated with primary graft dysfunction (PGD) after lung transplantation.

DESIGN

Prospective, multicenter cohort study.

METHODS

We measured plasma levels of protein C and PAI-1 before lung transplantation and 6, 24, 48, and 72 h after allograft reperfusion in 128 lung transplant recipients at six centers. The primary outcome was grade 3 PGD (Pa(O(2))/Fi(O(2)) < 200 with alveolar infiltrates) 72 h after transplantation. Biomarker profiles were evaluated using logistic regression and generalized estimating equations.

RESULTS

Patients who developed PGD had lower protein C levels 24 h posttransplantation than did patients without PGD (mean +/- SD [relative to control]: 64 +/- 27 vs. 92 +/- 41%, respectively; p = 0.002). Patients with PGD also had PAI-1 levels that were almost double those of patients without PGD at 24 h (213 +/- 144 vs. 117 +/- 89 ng/ml, respectively; p < 0.001). Throughout the 72-h postoperative period, protein C levels were significantly lower (p = 0.007) and PAI-1 levels were higher (p = 0.026) in subjects with PGD than in others. These differences persisted despite adjustment for potential confounders in multivariate analyses. Higher recipient pulmonary artery pressures, measured immediately pretransplantation, were associated with higher PAI-1 levels and increased risk of PGD.

CONCLUSION

Lower postoperative protein C and higher PAI-1 plasma levels are associated with PGD after lung transplantation. Impaired fibrinolysis and enhanced coagulation may be important in PGD pathogenesis.

The Preoperative Evaluation of the Transplanted Patient for Nontransplant Surgery

With the improved success of solid-organ transplantation, there has been an increased willingness to transplant individuals previously felt to be unsuitable for such procedures. Factors such as age and various medical comorbidities are no longer considered contraindications to transplantation, and hence, an increasing number of recipients may require medical care not specifically related to the transplant. After transplantation, many of these patients may require elective or emergent surgery, making it important for all surgeons to be familiar with the factors that may influence surgical outcomes in this population, asa well asa factors that affect postoperative care. Most transplant centres use a team approach to manage these complex patients, relying on medical professionals experienced in their care and management. Close interaction with the transplant team is likely the single most important step in preparing the transplanted patient for surgery and managing their postoperative care.

Classification and approach to bronchiolar diseases

PURPOSE OF REVIEW

Bronchiolar abnormalities are relatively common and occur in a variety of clinical contexts. There have been an increasing number of terms, some of which are redundant, used in referring to various forms of bronchiolar disorders. The purpose of this review is to provide an updated classification scheme to facilitate the clinical approach to patients with suspected bronchiolar disease.

RECENT FINDINGS

The spectrum of bronchiolar disorders is broader and more heterogeneous than previously recognized. In deciphering the potential significance of bronchiolar abnormalities, it is useful to distinguish those disorders in which the bronchiolar involvement is the dominant pathologic process, that is, primary bronchiolar disorders, from parenchymal or large airway diseases in which the bronchioles may become secondarily involved. Primary bronchiolar disorders include respiratory bronchiolitis, acute bronchiolitis, constrictive bronchiolitis, follicular bronchiolitis, diffuse panbronchiolitis, mineral dust airway disease, and a few other variants. Interstitial lung diseases with a prominent bronchiolar involvement include smoking-related interstitial lung diseases, cryptogenic organizing pneumonia, and hypersensitivity pneumonitis. Bronchiolitis can also be seen in large airway diseases such as chronic bronchitis, bronchiectasis, and asthma.

SUMMARY

In the clinical approach to a patient with bronchiolar disease, primary bronchiolar disorders should be distinguished from predominantly parenchymal or large airway processes with bronchiolar involvement. The number of patterns of bronchiolar response to injury is limited and these patterns are generally non-specific in regard to cause. Appropriate diagnosis and management of patients with bronchiolar disorders depend on judicious correlation of clinical, physiologic, and morphologic manifestations.

Telephone-based coping skills training for patients awaiting lung transplantation

Impaired quality of life is associated with increased mortality in patients with advanced lung disease. Using a randomized controlled trial with allocation concealment and blinded outcome assessment at 2 tertiary care teaching hospitals, the authors randomly assigned 328 patients with end-stage lung disease awaiting lung transplantation to 12 weeks of telephone-based coping skills training (CST) or to usual medical care (UMC). Patients completed a battery of quality of life instruments and were followed for up to 3.4 years to assess all-cause mortality. Compared with UMC, CST produced lower scores on perceived stress, anxiety, depressive symptoms, and negative affect and improved scores on mental health functioning, optimism, vitality, and perceived social support. There were 29 deaths (9%) over a mean follow-up period of 1.1 year. Survival analyses revealed that there was no difference in survival between the 2 groups. The authors conclude that a telephone-based CST intervention can be effectively delivered to patients awaiting lung transplantation. Despite the severity of pulmonary disease in this patient population, significant improvements in quality of life, but not somatic measures or survival to transplant, were achieved.