ABSTRACT
Preliminary evidence suggests that postoperative cognitive dysfunction (POCD) is common after lung transplantation. The impact of POCD on clinical outcomes has yet to be studied. The association between POCD and longer-term survival was therefore examined in a pilot study of posttransplantation survivors. Forty-nine participants from a prior randomized clinical trial underwent a neurocognitive assessment battery pretransplantation and 6 months posttransplantation, including assessments of the domains of Executive Function (Trail Making Test, Stroop, Digit Span), Processing Speed (Ruff 2 and 7 Test, Digit Symbol Substitution Test), and Verbal Memory (Verbal Paired Associates, Logical Memory, Animal Naming, and Controlled Oral Word Association Test). During a 13-year follow-up, 33 (67%) participants died. Greater neurocognition was associated with longer survival (hazard ratio [HR] = 0.49 [0.25-0.96], P = .039), and this association was strongest on tests assessing Processing Speed (HR = 0.58 [0.36-0.95], P = .03) and Executive Function (HR = 0.52 [0.28-0.97], P = .040). In addition, unadjusted analyses suggested an association between greater Memory performance and lower risk of CLAD (HR = 0.54 [0.29-1.00], P = .050). Declines in Executive Function tended to be predictive of worse survival. These preliminary findings suggest that postoperative neurocognition is predictive of subsequent mortality among lung transplant recipients. Further research is needed to confirm these findings in a larger sample and to examine mechanisms responsible for this relationship.
Subject(s)
Cognition Disorders/mortality , Graft Rejection/mortality , Lung Transplantation/adverse effects , Postoperative Complications , Quality of Life , Cognition Disorders/etiology , Female , Follow-Up Studies , Graft Rejection/etiology , Graft Survival , Humans , Male , Middle Aged , Neuropsychological Tests , Pilot Projects , Prognosis , Risk Factors , Survival RateABSTRACT
The choice of a single or bilateral lung transplant for interstitial lung disease (ILD) is controversial, as surgical risk, long-term survival and organ allocation are competing factors. In an effort to balance risk and benefit, our center adopted a staged bilateral lung transplant approach for higher surgical risk ILD patients where the patient has a single lung transplant followed by a second single transplant at a later date. We sought to understand the surgical risk, organ allocation and early outcomes of these staged bilateral recipients as a group and in comparison to matched single and bilateral recipients. Our analysis demonstrates that staged bilateral lung transplant recipients (n = 12) have a higher lung allocation score (LAS), lower pulmonary function tests and a lower glomerular filtration rate prior to the first transplant compared to the second (p < 0.01). There was a shorter length of hospital stay for the second transplant (p = 0.02). The staged bilateral compared to the single and bilateral case-matched controls had comparable short-term survival (p = 0.20) and pulmonary function tests at 1 year. There was a higher incidence of renal injury in the conventional bilateral group compared to the single and staged bilateral groups. The staged bilateral procedure is a viable option in select ILD patients.
Subject(s)
Graft Survival , Length of Stay/statistics & numerical data , Lung Diseases, Interstitial/mortality , Lung Transplantation/methods , Postoperative Complications , Adult , Aged , Female , Follow-Up Studies , Humans , Lung Diseases, Interstitial/surgery , Lung Transplantation/mortality , Male , Middle Aged , Prognosis , Respiratory Function Tests , Retrospective Studies , Risk Assessment , Survival Rate , Time FactorsABSTRACT
Lung transplantation has become an increasingly common treatment for patients with end-stage lung disease. Few studies have examined psychosocial risk factors for mortality in transplant recipients, despite evidence suggesting that elevated levels of negative affect are associated with greater mortality following major cardiac surgery. We therefore examined the relationship between negative affect early after lung transplantation and long-term survival in a sample of 132 lung transplant recipients (28 cystic fibrosis, 64 chronic obstructive pulmonary disease, 26 idiopathic pulmonary fibrosis, 14 other) followed for up to 13.5 years (median 7.4 years) following transplantation. Patients underwent both medical and psychosocial assessments 6 months following transplantation, which included the Beck Depression Inventory-II (BDI-II), Spielberger Anxiety Inventory, and General Health Questionnaire (GHQ). Over the course of follow-up, 80 (61%) participants died. Controlling for demographic factors, native lung disease, disease severity, family income, education level, social support, and frequency of posttransplant rejection, elevated symptoms of depression (BDI-II: HR = 1.31, p = 0.011) and distress (GHQ: HR = 1.28, p = 0.003) were associated with increased mortality. Higher levels of depression and general distress, but not anxiety, measured 6 months following lung transplantation are associated with increased mortality, independent of background characteristics and medical predictors.
Subject(s)
Anxiety/mortality , Depressive Disorder, Major/mortality , Lung Transplantation/psychology , Postoperative Complications , Transplant Recipients/psychology , Anxiety/diagnosis , Anxiety/psychology , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/psychology , Female , Follow-Up Studies , Graft Rejection , Graft Survival , Humans , Lung Transplantation/adverse effects , Lung Transplantation/mortality , Male , Middle Aged , Prognosis , Risk FactorsABSTRACT
Primary graft dysfunction (PGD) is a possible risk factor for bronchiolitis obliterans syndrome (BOS) following lung transplantation; however, the mechanism for any such association is poorly understood. Based on the association of TGF-ß with acute and chronic inflammatory disorders, we hypothesized that it might play a role in the continuum between PGD and BOS. Thus, the association between PGD and BOS was assessed in a single-center cohort of lung transplant recipients. Bronchoalveolar lavage fluid concentrations of TGF-ß and procollagen collected within 24 h of transplantation were compared across the spectrum of PGD, and incorporated into Cox models of BOS. Immunohistochemistry localized expression of TGF-ß and its receptor in early lung biopsies posttransplant. We found an association between PGD and BOS in both bilateral and single lung recipients with a hazard ratio of 3.07 (95% CI 1.76-5.38) for the most severe form of PGD. TGF-ß and procollagen concentrations were elevated during PGD (p < 0.01), and associated with increased rates of BOS. Expression of TGF-ß and its receptor localized to allograft infiltrating mononuclear and stromal cells, and the airway epithelium. These findings validate the association between PGD and the subsequent development of BOS, and suggest that this association may be mediated by receptor/TGF-ß biology.
Subject(s)
Biomarkers/metabolism , Bronchiolitis Obliterans/diagnosis , Graft Rejection/diagnosis , Lung Transplantation/adverse effects , Primary Graft Dysfunction/diagnosis , Transforming Growth Factor beta/metabolism , Aged , Bronchiolitis Obliterans/etiology , Bronchiolitis Obliterans/metabolism , Case-Control Studies , Female , Follow-Up Studies , Graft Rejection/blood , Graft Rejection/etiology , Graft Survival , Humans , Immunoenzyme Techniques , Lung Diseases/surgery , Male , Middle Aged , Postoperative Complications , Primary Graft Dysfunction/etiology , Primary Graft Dysfunction/metabolism , Prognosis , Prospective Studies , Retrospective Studies , Risk Assessment , Risk Factors , Severity of Illness IndexABSTRACT
The authors previously identified plasma plasminogen activator inhibitor-1 (PAI-1) level as a quantitative lung injury biomarker in primary graft dysfunction (PGD). They hypothesized that plasma levels of PAI-1 used as a quantitative trait could facilitate discovery of genetic loci important in PGD pathogenesis. A two-stage cohort study was performed. In stage 1, they tested associations of loci with PAI-1 plasma level using linear modeling. Genotyping was performed using the Illumina CVD Bead Chip v2. Loci meeting a p < 5 × 10(-4) cutoff were carried forward and tested in stage 2 for association with PGD. Two hundred ninety-seven enrollees were evaluated in stage 1. Six loci, associated with PAI-1, were carried forward to stage 2 and evaluated in 728 patients. rs3168046 (Toll interacting protein [TOLLIP]) was significantly associated with PGD (p = 0.006). The increased risk of PGD for carrying at least one copy of this variant was 11.7% (95% confidence interval 4.9-18.5%). The false-positive rate for individuals with this genotype who did not have PGD was 6.1%. Variants in the TOLLIP gene are associated with higher circulating PAI-1 plasma levels and validate for association with clinical PGD. A protein quantitative trait analysis for PGD risk prioritizes genetic variations in TOLLIP and supports a role for Toll-like receptors in PGD pathogenesis.
Subject(s)
Biomarkers/analysis , Genetic Variation/genetics , Intracellular Signaling Peptides and Proteins/genetics , Lung Transplantation/adverse effects , Primary Graft Dysfunction/diagnosis , Quantitative Trait Loci , Adult , Female , Follow-Up Studies , Genotype , Humans , Male , Middle Aged , Phenotype , Plasminogen Activator Inhibitor 1/blood , Primary Graft Dysfunction/blood , Primary Graft Dysfunction/etiology , Prognosis , Prospective StudiesABSTRACT
Chronic lung allograft dysfunction (CLAD) remains a major problem after lung transplantation with no definitive treatment except redo lung transplantation (re-LTx) in selected candidates. However, CLAD is not a homogeneous entity and different phenotypes exist. Therefore, we aimed to evaluate the effect of CLAD phenotypes on survival after re-LTx for CLAD. Patients who underwent re-LTx for respiratory failure secondary to CLAD in four LTx centers between 2003 and 2013 were included in this retrospective analysis. Bronchiolitis obliterans syndrome (BOS) and restrictive CLAD (rCLAD) were distinguished using pulmonary function, radiology and explant lung histopathology. Patient variables pre- and post-re-LTx were collected and analyzed. A total of 143 patients underwent re-LTx for CLAD resulting in 94 BOS (66%) and 49 rCLAD (34%) patients. Unadjusted and adjusted survival after re-LTx for rCLAD was worse compared to BOS (HR = 2.60, 1.59-4.24; p < 0.0001 and HR = 2.61, 1.51-4.51; p = 0.0006, respectively). Patients waiting at home prior to re-LTx experienced better survival compared to hospitalized patients (HR 0.40; 0.23-0.72; p = 0.0022). Patients with rCLAD redeveloped CLAD earlier and were more likely to redevelop rCLAD. Survival after re-LTx for rCLAD is worse compared to BOS. Consequently, re-LTx for rCLAD should be critically discussed, particularly when additional peri-operative risk factors are present.
Subject(s)
Lung Transplantation , Primary Graft Dysfunction , Adult , Female , Humans , Male , Middle Aged , Phenotype , Survival Rate , Young AdultABSTRACT
Peatlands are important sources of fluvial carbon. Previous research has shown that riverine dissolved organic carbon (DOC) concentrations are largely controlled by soil type. However, there has been little work to establish the controls of riverine DOC within blanket peatlands that have not undergone major disturbance from drainage or burning. A total of 119 peatland catchments were sampled for riverine DOC and water colour across three drainage basins during six repeated sampling campaigns. The topographic characteristics of each catchment were determined from digital elevation models. The dominant vegetation cover was mapped using 0.5m resolution colour infrared aerial images, with ground-truthed validation revealing 82% accuracy. Forward and backward stepwise regression modelling showed that mean slope was a strong (and negative) determinant of DOC and water colour in blanket peatland river waters. There was a weak role for plant functional type in determining DOC and water colour. At the basin scale, there were major differences between the models depending on the basin. The dominance of topographic predictors of DOC found in our study, combined with a weaker role of vegetation type, paves the way for developing improved planning tools for water companies operating in peatland catchments. Using topographic data and aerial imagery it will be possible to predict which tributaries will typically yield lower DOC concentrations and which are therefore more suitable and cost-effective as raw water intakes.
ABSTRACT
Primary graft dysfunction (PGD) is a major cause of early mortality after lung transplant. We aimed to define objective estimates of PGD risk based on readily available clinical variables, using a prospective study of 11 centers in the Lung Transplant Outcomes Group (LTOG). Derivation included 1255 subjects from 2002 to 2010; with separate validation in 382 subjects accrued from 2011 to 2012. We used logistic regression to identify predictors of grade 3 PGD at 48/72 h, and decision curve methods to assess impact on clinical decisions. 211/1255 subjects in the derivation and 56/382 subjects in the validation developed PGD. We developed three prediction models, where low-risk recipients had a normal BMI (18.5-25 kg/m(2) ), chronic obstructive pulmonary disease/cystic fibrosis, and absent or mild pulmonary hypertension (mPAP<40 mmHg). All others were considered higher-risk. Low-risk recipients had a predicted PGD risk of 4-7%, and high-risk a predicted PGD risk of 15-18%. Adding a donor-smoking lung to a higher-risk recipient significantly increased PGD risk, although risk did not change in low-risk recipients. Validation demonstrated that probability estimates were generally accurate and that models worked best at baseline PGD incidences between 5% and 25%. We conclude that valid estimates of PGD risk can be produced using readily available clinical variables.
Subject(s)
Lung Transplantation , Primary Graft Dysfunction , Adult , Female , Humans , Male , Risk FactorsABSTRACT
BACKGROUND: Delirium is relatively common after lung transplantation, although its prevalence and prognostic significance have not been systematically studied. The purpose of the present study was to examine pretransplant predictors of delirium and the short-term impact of delirium on clinical outcomes among lung transplant recipients. METHODS: Participants underwent pretransplant cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status and the Trail Making Test. After transplant, delirium was assessed using the Confusion Assessment Method until discharge. RESULTS: Sixty-three patients were transplanted between March and November 2013, of which 23 (37%) developed delirium. Among transplanted patients, 48 patients completed pretransplant cognitive testing. Better pretransplant cognitive function was associated with lower risk of delirium (odds ratio, 0.69 [95% confidence interval 0.48, 0.99], P = .043); and demographic and clinical features including native disease (P = .236), the Charlson comorbidity index (P = .581), and the lung allocation score (P = .871) were unrelated to risk of delirium, although there was a trend for women to experience delirium less frequently (P = .071). The presence (P = .006) and duration (P = .027) of delirium were both associated with longer hospital stays. CONCLUSION: Delirium occurs in more than one-third of patients after lung transplantation. Delirium was associated with poorer pretransplant cognitive functioning and longer hospital stays, after accounting for other medical and demographic factors.
Subject(s)
Cognition , Delirium/etiology , Length of Stay , Lung Transplantation/adverse effects , Adult , Aged , Confusion/diagnosis , Delirium/diagnosis , Delirium/epidemiology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Odds Ratio , Prevalence , Prognosis , Prospective Studies , Trail Making TestABSTRACT
This editorial puts into perspective the findings of the first randomized, controlled trial examining alemtuzumab induction for lung transplantation, and highlights the challenges encountered with alemtuzumab induction in other solid organs. See article by Jaksch et al on page 1839.
Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Lung Transplantation , Alemtuzumab , Female , Humans , MaleABSTRACT
As HLAs antibody detection technology has evolved, there is now detailed HLA antibody information available on prospective transplant recipients. Determining single antigen antibody specificity allows for a calculated panel reactive antibodies (cPRA) value, providing an estimate of the effective donor pool. For broadly sensitized lung transplant candidates (cPRA ≥ 80%), our center adopted a pretransplant multi-modal desensitization protocol in an effort to decrease the cPRA and expand the donor pool. This desensitization protocol included plasmapheresis, solumedrol, bortezomib and rituximab given in combination over 19 days followed by intravenous immunoglobulin. Eight of 18 candidates completed therapy with the primary reasons for early discontinuation being transplant (by avoiding unacceptable antigens) or thrombocytopenia. In a mixed-model analysis, there were no significant changes in PRA or cPRA changes over time with the protocol. A sub-analysis of the median fluorescence intensity (MFI) change indicated a small decline that was significant in antibodies with MFI 5000-10,000. Nine of 18 candidates subsequently had a transplant. Posttransplant survival in these nine recipients was comparable to other pretransplant-sensitized recipients who did not receive therapy. In summary, an aggressive multi-modal desensitization protocol does not significantly reduce pretransplant HLA antibodies in a broadly sensitized lung transplant candidate cohort.
Subject(s)
Desensitization, Immunologic , Graft Rejection/prevention & control , Hypersensitivity/drug therapy , Immunoglobulins, Intravenous/therapeutic use , Isoantibodies/immunology , Lung Diseases/surgery , Lung Transplantation , Aged , Cohort Studies , Female , Follow-Up Studies , Graft Rejection/immunology , Graft Rejection/mortality , HLA Antigens/immunology , Humans , Immunoglobulins, Intravenous/immunology , Immunosuppressive Agents/therapeutic use , Lung Diseases/mortality , Male , Middle Aged , Plasmapheresis , Prognosis , Risk Factors , Survival RateABSTRACT
Inherent recipient factors, including pretransplant diagnosis, obesity and elevated pulmonary pressures, are established primary graft dysfunction (PGD) risks. We evaluated the relationship between preoperative lung injury biomarkers and PGD to gain further mechanistic insight in recipients. We performed a prospective cohort study of recipients in the Lung Transplant Outcomes Group enrolled between 2002 and 2010. Our primary outcome was Grade 3 PGD on Day 2 or 3. We measured preoperative plasma levels of five biomarkers (CC-16, sRAGE, ICAM-1, IL-8 and Protein C) that were previously associated with PGD when measured at the postoperative time point. We used multivariable logistic regression to adjust for potential confounders. Of 714 subjects, 130 (18%) developed PGD. Median CC-16 levels were elevated in subjects with PGD (10.1 vs. 6.0, p<0.001). CC-16 was associated with PGD in nonidiopathic pulmonary fibrosis (non-IPF) subjects (OR for highest quartile of CC-16: 2.87, 95% CI: 1.37, 6.00, p=0.005) but not in subjects with IPF (OR 1.38, 95% CI: 0.43, 4.45, p=0.59). After adjustment, preoperative CC-16 levels remained associated with PGD (OR: 3.03, 95% CI: 1.26, 7.30, p=0.013) in non-IPF subjects. Our study suggests the importance of preexisting airway epithelial injury in PGD. Markers of airway epithelial injury may be helpful in pretransplant risk stratification in specific recipients.
Subject(s)
Biomarkers/blood , Lung Diseases/surgery , Lung Transplantation/adverse effects , Primary Graft Dysfunction/diagnosis , Uteroglobin/blood , Adult , Aged , Female , Follow-Up Studies , Humans , Lung Diseases/blood , Male , Middle Aged , Preoperative Care , Primary Graft Dysfunction/blood , Primary Graft Dysfunction/etiology , Prognosis , Prospective StudiesABSTRACT
Aspergillus colonization after lung transplantation may increase the risk for bronchiolitis obliterans syndrome (BOS), a disease of small airways. We hypothesized that colonization with small conidia Aspergillus species would be associated with a greater risk of BOS, based upon an increased likelihood of deposition in small airways. We studied adult primary lung recipients from two large centers; 298 recipients at University of California, Los Angeles and 482 recipients at Duke University Medical Center. We grouped Aspergillus species by conidia diameter≤3.5 µm. We assessed the relationship of colonization with outcomes in Cox models. Pre-BOS colonization with small conidia Aspergillus species, but not large, was a risk factor for BOS (p=0.002, HR 1.44, 95% CI 1.14-1.82), along with acute rejection, single lung and Pseudomonas. Colonization with small conidia species also associated with risk of death (p=0.03, HR 1.30, 95% CI 1.03-1.64). Although other virulence traits besides conidia size may be important, we have demonstrated in two large independent cohorts that colonization with small conidia Aspergillus species increases the risk of BOS and death. Prospective evaluation of strategies to prevent Aspergillus colonization of small airways is warranted, with the goal of preserving lung allograft function as long as possible.
Subject(s)
Aspergillosis/complications , Aspergillus/pathogenicity , Bronchiolitis Obliterans/etiology , Lung Transplantation/adverse effects , Aged , Aspergillosis/diagnosis , Bronchiolitis Obliterans/microbiology , California , Cohort Studies , Female , Humans , Male , Middle Aged , North Carolina , Proportional Hazards Models , Pseudomonas Infections/diagnosis , Respiratory Function Tests , Risk Factors , Spores, Fungal/pathogenicityABSTRACT
Bronchiolitis obliterans syndrome (BOS), a condition of irreversible small airway fibrosis, is the principal factor limiting long-term survival after lung transplantation. Bronchoscopy and bronchoalveolar lavage (BAL), techniques central to lung transplant clinical practice, provide a unique opportunity to interrogate the lung allograft during BOS development and identify potential disease mechanisms or biomarkers. Over the past 20 years, numerous studies have evaluated the BAL cellular composition, cytokine profiles and protein constituents in lung transplant recipients with BOS. To date, however, no summative evaluation of this literature has been reported. We developed and applied objective criteria to qualitatively rank the strength of associations between BAL parameters and BOS in order to provide a comprehensive and systematic assessment of the literature. Our analysis indicates that several BAL parameters, including neutrophil count, interleukin-8, alpha defensins and MMP-9, demonstrate highly replicable associations with BOS. Additionally, we suggest that considerable opportunity exists to increase the knowledge gained from BAL analyses in BOS through increased sample sizes, covariant adjustment and standardization of the BAL technique. Further efforts to leverage analysis of BAL constituents in BOS may offer great potential to provide additional in-depth and mechanistic insights into the pathogenesis of this complex disease.
Subject(s)
Biomarkers/analysis , Bronchiolitis Obliterans/diagnosis , Bronchoalveolar Lavage Fluid/chemistry , Humans , SyndromeABSTRACT
Central airways stenosis (CAS) after lung transplant is a poorly understood complication. Objectives of this study were to determine if CAS was associated with chronic rejection or worse survival after transplant as well as to identify factors associated with CAS in a large cohort of lung transplant recipients. Lung transplant recipients transplanted at a single center were retrospectively reviewed for the development of CAS requiring airway dilation. A total of 467 subjects met inclusion criteria with 60 (13%) of these developing CAS requiring intervention. Of these 60 recipients, 22 (37%) had resolution of CAS with bronchoplasty alone, while 32 (53%) ultimately required stent placement. CAS that required intervention was not a risk factor for the development of bronchiolitis obliterans syndrome or worse overall survival. Significant risk factors for the subsequent development of CAS in a time-dependant multivariable model were pulmonary fungal infections and the need for postoperative tracheostomy. While CAS was not associated with BOS or worse survival, it remains an important complication after lung transplant with potentially preventable risk factors.
Subject(s)
Bronchiolitis Obliterans/etiology , Constriction, Pathologic/etiology , Lung Transplantation/adverse effects , Adult , Bronchiolitis Obliterans/diagnosis , Constriction, Pathologic/therapy , Female , Forced Expiratory Volume , Graft Rejection , Humans , Lung Transplantation/methods , Male , Middle Aged , Prognosis , Retrospective Studies , Risk Factors , Spirometry , Stents , Transplantation, Homologous , Treatment OutcomeABSTRACT
Bronchiolitis obliterans syndrome (BOS) is a condition of progressive airflow obstruction that affects a majority of lung transplant recipients and limits long-term posttransplant survival. Although epithelial injury appears central to the development of BOS, little is known regarding the specific epithelial cell types that are affected in this condition. We hypothesized that BOS would involve preferential injury to the secretory Clara cells that function in innate defense and epithelial repair. To test this hypothesis, we assessed tissue transcript, tissue protein and lung fluid protein expression of Clara cell secretory protein (CCSP), a marker for Clara cells, in lung transplant recipients with BOS, BOS-free patients and in donor controls. Our results demonstrate that CCSP tissue transcript and protein expression are significantly reduced in lung transplant recipients with BOS compared to BOS-free or donor controls. In addition, we demonstrate that CCSP protein levels are significantly reduced in the lung fluid of patients with BOS compared to BOS-free controls, in cross-sectional and longitudinal analysis. Collectively, these complementary results illustrate that BOS involves a selective alteration in the distribution and function of bronchiolar Clara cells.
Subject(s)
Bronchiolitis Obliterans/etiology , Bronchiolitis Obliterans/pathology , Bronchoalveolar Lavage Fluid/cytology , Epithelial Cells/metabolism , Lung Transplantation/adverse effects , Uteroglobin/metabolism , Adult , Biomarkers/metabolism , Case-Control Studies , Epithelial Cells/pathology , Female , Fluorescent Antibody Technique , Graft Rejection , Graft Survival , Humans , Immunohistochemistry , Lung Transplantation/methods , Male , Middle Aged , Prognosis , Prospective Studies , Reference Values , Risk Factors , Severity of Illness Index , Syndrome , Uteroglobin/geneticsABSTRACT
Discolouration of natural surface waters due to the humic component of dissolved organic carbon (DOC) is a costly problem for water supply companies. This paper reviews what is known about the impacts of prescribed moorland vegetation burning on water colour. Relevant research has taken place at three scales: laboratory experiments on peat cores, plot scale sampling of soil waters and catchment scale sampling of stream waters. While laboratory studies suggest burning increases colour production, the evidence from catchment and plot studies is contradictory. Plot studies suggest colour production may decrease or remain unchanged following burning although there is evidence for some transient changes. Catchment studies suggest prescribed moorland burning causes stream water colour to increase, although in most cases the evidence is not clear cut since most studies could not clearly disentangle the effects of burning from those of vegetation cover. The differences in findings between plot and catchment studies may be explained by: i) the short-term nature of some studies which do not measure long-term response and recovery times to burning; ii) the lack of colour measurements from shallow soil depths which contribute more to streamflow than soil water from deeper in the peat; and iii) the possibility of hydrological interactions occurring between different experimental plots at some sites. Additionally, the increase in recent patch burning in some catchments that has been statistically attributed by some authors to increases in stream water colour cannot be reconciled with theoretical calculations. When dilution with waters derived from other parts of the catchment are taken into account, large values of colour have to be theoretically derived from those recently burnt areas that occupy a small proportion of the catchment area in order to balance the change in stream water colour observed in recent years. Therefore, much further process-based work is required to properly investigate whether prescribed vegetation burning is a direct driver of enhanced colour and DOC in upland streams, rivers and lakes.
Subject(s)
Color , Fires , Fresh Water , Water Quality , Carbon , Groundwater , Lakes , Rivers , SoilABSTRACT
Acute rejection (AR) is a common complication following lung transplantation and is an established risk factor for bronchiolitis obliterans syndrome (BOS). AR clinical presentation varies considerably and is sometimes associated with an acute decrease in forced expiratory volume in 1 s (FEV1). We hypothesized that lung transplant recipients who experience such spirometrically significant AR (SSAR), as defined by a ≥10% decline in FEV1 relative to the prior pulmonary function test, are subsequently at increased risk for BOS and worse overall survival. In a large single center cohort (n = 339), SSAR occurred in 79 subjects (23%) and significantly increased the risk for BOS (p < 0.0001, HR = 3.2, 95% CI 2.3-4.6) and death (p = 0.0001, HR = 2.3, 95% CI 1.5-3.5). These effects persisted after multivariate adjustment for pre-BOS AR and lymphocytic bronchiolitis burden. An analysis of the subset of patients who experienced severe SSAR (≥20% decline in FEV1) resulted in even greater hazards for BOS and death. Thus, we demonstrate a novel physiological measure that allows discrimination of patients at increased risk for worse posttransplant outcomes. Further studies are needed to determine mechanisms of airflow impairment and whether aggressive clinical interventions could improve post-SSAR outcomes.
Subject(s)
Bronchiolitis Obliterans/diagnosis , Bronchiolitis Obliterans/mortality , Graft Rejection/etiology , Graft Rejection/mortality , Lung Transplantation/adverse effects , Postoperative Complications , Acute Disease , Adult , Bronchiolitis Obliterans/etiology , Female , Follow-Up Studies , Forced Expiratory Volume , Graft Rejection/diagnosis , Humans , Male , Middle Aged , Prognosis , Prospective Studies , Risk Factors , Survival RateABSTRACT
Cytomegalovirus (CMV) is the most prevalent opportunistic infection that occurs in lung-transplant recipients. In addition to its direct morbidity, multiple studies have demonstrated that CMV, in particular CMV pneumonia, is associated with an increased risk for chronic graft dysfunction manifested as bronchiolitis obliterans syndrome (BOS) and worse posttransplant survival. Therefore, prevention of CMV remains an important goal to improve long-term lung-transplant outcomes. Although centers often employed 3 months of prophylaxis in at-risk patients after lung transplantation, a significant proportion of patients still developed infection or disease after the discontinuation of prophylaxis, highlighting the need for more effective approaches to CMV prevention. A number of early single-center reports suggested benefit to extending prophylaxis to longer durations, but concerns regarding cost, late-onset CMV disease, viral resistance and bone marrow toxicity limited enthusiasm for longer durations. However, several recent studies including a multicenter, prospective, randomized, double-blinded clinical trial have demonstrated significant benefits to extending CMV prophylaxis beyond 3 months. Although some areas of controversy remain, the clinical implications of these recent studies suggest that extending prophylaxis with valganciclovir up to 12 months is clearly beneficial for CMV prevention after lung transplantation.
Subject(s)
Cytomegalovirus Infections/etiology , Cytomegalovirus Infections/prevention & control , Cytomegalovirus/pathogenicity , Lung Transplantation/adverse effects , HumansABSTRACT
Primary graft dysfunction (PGD) after lung transplantation may result from ischemia reperfusion injury (IRI). The innate immune response to IRI may be mediated by Toll-like receptor and IL-1-induced long pentraxin-3 (PTX3) release. We hypothesized that elevated PTX3 levels were associated with PGD. We performed a nested case control study of lung transplant recipients with idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD) from the Lung Transplant Outcomes Group cohort. PTX3 levels were measured pretransplant, and 6 and 24 h postreperfusion. Cases were subjects with grade 3 PGD within 72 h of transplantation and controls were those without grade 3 PGD. Generalized estimating equations and multivariable logistic regression were used for analysis. We selected 40 PGD cases and 79 non-PGD controls. Plasma PTX3 level was associated with PGD in IPF but not COPD recipients (p for interaction < 0.03). Among patients with IPF, PTX3 levels at 6 and 24 h were associated with PGD (OR = 1.6, p = 0.02 at 6 h; OR = 1.4, p = 0.008 at 24 h). Elevated PTX3 levels were associated with the development of PGD after lung transplantation in IPF patients. Future studies evaluating the role of innate immune activation in IPF and PGD are warranted.