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BACKGROUND: Smokers manifest varied phenotypes of pulmonary impairment. RESEARCH QUESTION: Which pulmonary phenotypes are associated with coronary artery disease (CAD) in smokers? STUDY DESIGN AND METHODS: We analyzed data from the University of Pittsburgh COPD Specialized Center for Clinically Oriented Research (SCCOR) cohort (n = 481) and the Genetic Epidemiology of COPD (COPDGene) cohort (n = 2,580). Participants were current and former smokers with > 10 pack-years of tobacco exposure. Data from the two cohorts were analyzed separately because of methodologic differences. Lung hyperinflation was assessed by plethysmography in the SCCOR cohort and by inspiratory and expiratory CT scan lung volumes in the COPDGene cohort. Subclinical CAD was assessed as the coronary artery calcium score, whereas clinical CAD was defined as a self-reported history of CAD or myocardial infarction (MI). Analyses were performed in all smokers and then repeated in those with airflow obstruction (FEV(1) to FVC ratio, < 0.70). RESULTS: Pulmonary phenotypes, including airflow limitation, emphysema, lung hyperinflation, diffusion capacity, and radiographic measures of airway remodeling, showed weak to moderate correlations (r < 0.7) with each other. In multivariate models adjusted for pulmonary phenotypes and CAD risk factors, lung hyperinflation was the only phenotype associated with calcium score, history of clinical CAD, or history of MI (per 0.2 higher expiratory and inspiratory CT scan lung volume; coronary calcium: OR, 1.2; 95% CI, 1.1-1.5; P = .02; clinical CAD: OR, 1.6; 95% CI, 1.1-2.3; P = .01; and MI in COPDGene: OR, 1.7; 95% CI, 1.0-2.8; P = .05). FEV(1) and emphysema were associated with increased risk of CAD (P < .05) in models adjusted for CAD risk factors; however, these associations were attenuated on adjusting for lung hyperinflation. Results were the same in those with airflow obstruction and were present in both cohorts. INTERPRETATION: Lung hyperinflation is associated strongly with clinical and subclinical CAD in smokers, including those with airflow obstruction. After lung hyperinflation was accounted for, FEV(1) and emphysema no longer were associated with CAD. Subsequent studies should consider measuring lung hyperinflation and examining its mechanistic role in CAD in current and former smokers.

This study aimed to describe the characteristics of COVID-19 cases and close contacts during the first wave of COVID-19 in Malaysia (23 January 2020 to 26 February 2020), and to analyse the reasons why the outbreak did not continue to spread and lessons that can be learnt from this experience. Characteristics of the cases and close contacts, spatial spread, epidemiological link, and timeline of the cases were examined. An extended SEIR model was developed using several parameters such as the average number of contacts per day per case, the proportion of close contact traced per day and the mean daily rate at which infectious cases are isolated to determine the basic reproduction number (R0) and trajectory of cases. During the first wave, a total of 22 cases with 368 close contacts were traced, identified, tested, quarantine and isolated. Due to the effective and robust outbreak control measures put in place such as early case detection, active screening, extensive contact tracing, testing and prompt isolation/quarantine, the outbreak was successfully contained and controlled. The SEIR model estimated the R0 at 0.9 which further supports the decreasing disease dynamics and early termination of the outbreak. As a result, there was a 11-day gap (free of cases) between the first and second wave which indicates that the first wave was not linked to the second wave.

ObjectivesTo develop predictive criteria for COVID-19-associated cytokine storm (CS), a severe hyperimmune response that results in organ damage in some patients infected with COVID-19. We hypothesised that criteria for inflammation and cell death would predict this type of CS.MethodsWe analysed 513 hospitalised patients who were positive for COVID-19 reverse transcriptase PCR and for ground-glass opacity by chest high-resolution CT. To achieve an early diagnosis, we analysed the laboratory results of the first 7 days of hospitalisation. We implemented logistic regression and principal component analysis to determine the predictive criteria. We used a ‘genetic algorithm’ to derive the cut-offs for each laboratory result. We validated the criteria with a second cohort of 258 patients.ResultsWe found that the criteria for macrophage activation syndrome, haemophagocytic lymphohistiocytosis and the HScore did not identify the COVID-19 cytokine storm (COVID-CS). We developed new predictive criteria, with sensitivity and specificity of 0.85 and 0.80, respectively, comprising three clusters of laboratory results that involve (1) inflammation, (2) cell death and tissue damage, and (3) prerenal electrolyte imbalance. The criteria identified patients with longer hospitalisation and increased mortality. These results highlight the relevance of hyperinflammation and tissue damage in the COVID-CS.ConclusionsWe propose new early predictive criteria to identify the CS occurring in patients with COVID-19. The criteria can be readily used in clinical practice to determine the need for an early therapeutic regimen, block the hyperimmune response and possibly decrease mortality.

Chronic obstructive pulmonary disease (COPD) is becoming one of the leading causes of mortality and morbidity throughout the world. The National Emphysema Treatment Trial demonstrated that lung volume reduction surgery can improve pulmonary function, exercise capacity, and quality of life in select subgroups of patients with COPD. In recent years, few bronchoscopic lung volume reduction (BLVR) procedures have undergone clinical trials with the goal of establishing an effective and safe alternative approach for reducing hyperinflation in patients with severe emphysema who are symptomatic despite optimal medical management, but are poor surgical candidates. Of these BLVR procedures, only deployment of 1-way endobronchial valves (EBVs) has the largest pool of scientific data available to date to support its clinical utility. Two EBV systems have been food and drug administration-approved within the last year to meet the clinical demands of this select group of patients with COPD. On the basis of the results of multiple randomized clinical trials, the recommendations of the original 2016 Expert Panel Report on BLVR usage criteria of EBV have been updated in 2019. The outcome of EBV therapy is maximized in certain image-based COPD phenotypes. Imaging plays a major role in patient selection, target lobe identification, and in the management of postprocedural adverse events. With the expected widespread use of EBV therapy in the coming years, knowledge and familiarity of the Role of Imaging in BLVR using EBVs is essential for radiologists attempting to make meaningful contribution toward improving clinical outcomes.

OBJECTIVE. Adult neoplasms of the ribs are a heterogeneous group consisting of both benign and aggressive entities. Rib neoplasms have a variety of overlapping imaging features, with much of the imaging data disjointed across the musculoskeletal, thoracic, and oncologic imaging literature. Arrival at accurate diagnosis can therefore be quite challenging. This article consolidates this information and introduces the reader to an algorithmic approach to rib lesion evaluation based on imaging. CONCLUSION. Rib neoplasms are a diverse group of benign and malignant entities, which often makes determining an accurate diagnosis challenging. Evaluation requires a multipronged approach that incorporates radiographic imaging features, nonradiographic imaging findings, lesion location, and clinical data.

With many countries experiencing a resurgence in COVID-19 cases, it is important to forecast disease trends to enable effective planning and implementation of control measures. This study aims to develop Seasonal Autoregressive Integrated Moving Average (SARIMA) models using 593 data points and smoothened case and covariate time-series data to generate a 28-day forecast of COVID-19 case trends during the third wave in Malaysia. SARIMA models were developed using COVID-19 case data sourced from the Ministry of Health Malaysia’s official website. Model training and validation was conducted from 22 January 2020 to 5 September 2021 using daily COVID-19 case data. The SARIMA model with the lowest root mean square error (RMSE), mean absolute percentage error (MAE) and Bayesian information criterion (BIC) was selected to generate forecasts from 6 September to 3 October 2021. The best SARIMA model with a RMSE = 73.374, MAE = 39.716 and BIC = 8.656 showed a downward trend of COVID-19 cases during the forecast period, wherein the observed daily cases were within the forecast range. The majority (89%) of the difference between the forecasted and observed values was well within a deviation range of 25%. Based on this work, we conclude that SARIMA models developed in this paper using 593 data points and smoothened data and sensitive covariates can generate accurate forecast of COVID-19 case trends.

RATIONALE: Multiple studies have demonstrated an increased risk of chronic obstructive pulmonary disease (COPD) in heterozygous carriers of the AAT (alpha-1 antitrypsin) Z allele. However, it is not known if MZ subjects with COPD are phenotypically different from noncarriers (MM genotype) with COPD. OBJECTIVES: To assess if MZ subjects with COPD have different clinical features compared with MM subjects with COPD. METHODS: Genotypes of SERPINA1 were ascertained by using whole-genome sequencing data in three independent studies. We compared outcomes between MM subjects with COPD and MZ subjects with COPD in each study and combined the results in a meta-analysis. We performed longitudinal and survival analyses to compare outcomes in MM and MZ subjects with COPD over time. MEASUREMENTS AND MAIN RESULTS: We included 290 MZ subjects with COPD and 6,184 MM subjects with COPD across the three studies. MZ subjects had a lower FEV(1)% predicted and greater quantitative emphysema on chest computed tomography scans compared with MM subjects. In a meta-analysis, the FEV(1) was 3.9% lower (95% confidence interval [CI], −6.55% to −1.26%) and emphysema (the percentage of lung attenuation areas

Background Lung cancer screening (LCS) with Low-Dose CT (LDCT) decreases lung cancer mortality; however, screening benefits and harms are poorly described in minority populations. Our purpose is to report benefits and harms of LCS implemented in a safety-net institution. Because harms are rare, there is a paucity of clinical experience guiding Shared Decision Making (SDM) with diverse populations. Methods We conducted a prospective, observational study of patients undergoing LCS between September 2014 and March 2019 with 2-year follow-up. LDCT results, lung cancer diagnosis, stage, treatment, false-positive, false-negative procedure from a false-positive, complication from procedures, and death were recorded. Patient cases highlighting the challenges of delivering LCS to an underserved population were evaluated in the context of current evidence. Results 995 patients underwent screening, of which the majority were African American (54.9%), with 2.9% receiving a cancer diagnosis, a false-positive rate of 9.4% and a 0.7% rate of procedures resulting from a false-positive. Five patient cases highlight challenges namely 1) false-positive resulting in surgery, 2) false-negative,3) incidental finding, 4) delay in diagnosis, and 5) mortality from cause other than lung cancer. Conclusions LCS of a predominantly African American population with 2-year follow-up demonstrates early detection and treatment of lung cancer with few harms. Though rare, harms must be clearly described with population-specific evidence. We report clinical perspective of rare harms that can provide guidance to providers and patients.

BackgroundBody composition measures, specifically low weight or reduced muscle mass, are associated with mortality in COPD, but the effect of longitudinal body composition changes is undefined.Research questionIs the longitudinal loss of fat-free mass (FFM) associated with increased mortality, including in those with initially normal or elevated body composition metrics?Study design and methodsParticipants with complete data for at least one visit in the COPDGene study (n= 9,268) and the ECLIPSE study (n= 1,760) were included and monitored for 12 and 8 years, respectively. Pectoralis muscle area (PMA) was derived from thoracic CT scans and used as a proxy for FFM. A longitudinal mixed submodel for PMA and a Cox proportional hazards submodel for survival were fitted on a joint distribution, using a shared random intercept parameter and Markov chain Monte Carlo parameter estimation.ResultsBoth cohorts demonstrated a left-shifted distribution of baseline FFM, not reflected in BMI, and an increase in all-cause mortality risk associated with longitudinal loss of PMA. For each 1-cm2 PMA loss, mortality increased 3.1%(95%CI, 2.4%-3.7%; P< .001) in COPDGene, and 2.4%(95%CI, 0.9%-4.0%; P< .001) in ECLIPSE. Increased mortality risk was independent of enrollment values for BMI and disease severity [BODE (body mass, airflow obstruction, dyspnea, and exercise capacity) index quartiles] and was significant even in participants with initially greater than average PMA.InterpretationLongitudinal loss of PMA is associated with increased all-cause mortality, regardless of BMI or initial muscle mass. Consideration of novel screening tests and further research into mechanisms contributing to muscle decline may improve risk stratification and identify novel therapeutic targets in ever smokers.

Diaphragmatic dysfunction is a potential cause of dyspnea that can lead to significant morbidity. The purpose of this review article is to provide readers with the essentials for performing diaphragm ultrasonography, image interpretation, and the technical limitations one needs to be aware of. Diaphragm ultrasonography is simple to perform and has proven to be an accurate and safe bedside modality, overcoming many of the traditional limitations of fluoroscopy.

PURPOSE: Our aim was to develop a novel approach for lung cancer screening among a diverse population that integrates the Centers for Medicare and Medicaid Services (CMS) recommended components including shared decision making (SDM), low-dose CT (LDCT), reporting of results in a standardized format, smoking cessation, and arrangement of follow-up care. METHODS: Between October of 2015 and March of 2018, we enrolled patients, gathered data on demographics, delivery of SDM, reporting of LDCT results using Lung-RADS, discussion of results, and smoking cessation counseling. We measured adherence to follow-up care, cancer diagnosis, cancer treatment, and smoking cessation at 2 years after initial LDCT. RESULTS: We enrolled 505 patients who were 57% African American, 30% Caucasian, 13% Hispanic, < 1% Asian, and 61% were active smokers. All participants participated in SDM, 88.1% used a decision aid, and 96.1% proceeded with LDCT. Of 496 completing LDCT, all received a discussion about results and follow-up recommendations. Overall, 12.9% had Lung-RADS 3 or 4, and 3.2% were diagnosed with lung cancer resulting in a false-positive rate of 10.7%. All 48 patients with positive screens but no cancer diagnosis adhered to follow-up care at 1 year, but only 35.4% adhered to recommended follow-up care at 2 years. The annual follow-up for patients with negative lung cancer screening results (Lung-RADS 1 and 2) was only 23.7% after one year and 2.8% after 2 years. All active smokers received smoking cessation counseling, but only 11% quit smoking. CONCLUSION: The findings show that an integrated lung cancer screening program can be safely implemented in a diverse population, but adherence to annual screening is poor.

Background Attenuation of transforming growth factor β by blocking angiotensin II has been shown to reduce emphysema in a murine model. General population studies have demonstrated that the use of angiotensin converting enzyme inhibitors (ACEis) and angiotensin-receptor blockers (ARBs) is associated with reduction of emphysema progression in former smokers and that the use of ACEis is associated with reduction of FEV1 progression in current smokers. Research Question Is use of ACEi and ARB associated with less progression of emphysema and FEV1 decline among individuals with COPD or baseline emphysema? Methods Former and current smokers from the Genetic Epidemiology of COPD Study who attended baseline and 5-year follow-up visits, did not change smoking status, and underwent chest CT imaging were included. Adjusted linear mixed models were used to evaluate progression of adjusted lung density (ALD), percent emphysema (%total lung volume Results Over 5 years of follow-up, compared with nonusers, ACEi and ARB users with COPD showed slower ALD progression (adjusted mean difference [aMD], 1.6; 95% CI, 0.34-2.9). Slowed lung function decline was not observed based on phase 1 medication (aMD of FEV1 % predicted, 0.83; 95% CI, –0.62 to 2.3), but was when analysis was limited to consistent ACEi and ARB users (aMD of FEV1 % predicted, 1.9; 95% CI, 0.14-3.6). No effect modification by smoking status was found for radiographic outcomes, and the lung function effect was more pronounced in former smokers. Results were similar among participants with baseline emphysema. Interpretation Among participants with spirometry-confirmed COPD or baseline emphysema, ACEi and ARB use was associated with slower progression of emphysema and lung function decline. Trial Registry ClinicalTrials.gov ; No.: NCT00608764; URL: www.clinicaltrials.gov

Background Infection with the novel severe acute respiratory syndrome coronavirus 2 has been associated with a hypercoagulable state. Emerging data from China and Europe have consistently shown an increased incidence of venous thromboembolism (VTE). We aimed to identify the VTE incidence and early predictors of VTE at our high-volume tertiary care center. Methods We performed a retrospective cohort study of 147 patients who had been admitted to Temple University Hospital with coronavirus disease 2019 (COVID-19) from April 1, 2020 to April 27, 2020. We first identified the VTE (pulmonary embolism [PE] and deep vein thrombosis [DVT]) incidence in our cohort. The VTE and no-VTE groups were compared by univariable analysis for demographics, comorbidities, laboratory data, and treatment outcomes. Subsequently, multivariable logistic regression analysis was performed to identify the early predictors of VTE. Results The 147 patients (20.9% of all admissions) admitted to a designated COVID-19 unit at Temple University Hospital with a high clinical suspicion of acute VTE had undergone testing for VTE using computed tomography pulmonary angiography and/or extremity venous duplex ultrasonography. The overall incidence of VTE was 17% (25 of 147). Of the 25 patients, 16 had had acute PE, 14 had had acute DVT, and 5 had had both PE and DVT. The need for invasive mechanical ventilation (adjusted odds ratio, 3.19; 95% confidence interval, 1.07-9.55) and the admission D-dimer level ≥1500 ng/mL (adjusted odds ratio, 3.55; 95% confidence interval, 1.29-9.78) were independent markers associated with VTE. The all-cause mortality in the VTE group was greater than that in the non-VTE group (48% vs 22%; P = .007). Conclusions Our study represents one of the earliest reported from the United States on the incidence rate of VTE in patients with COVID-19. Patients with a high clinical suspicion and the identified risk factors (invasive mechanical ventilation, admission D-dimer level ≥1500 ng/mL) should be considered for early VTE testing. We did not screen all patients admitted for VTE; therefore, the true incidence of VTE could have been underestimated. Our findings require confirmation in future prospective studies.

Rationale Patients with combined pulmonary fibrosis and emphysema (CPFE) may develop acute exacerbations of IPF (AE-IPF) or COPD (AE-COPD). The incidence and the characteristics of exacerbations in patients with CPFE (e.g., COPD vs IPF) have not been well described. Objectives To compare the incidence and rate of exacerbations in patients with CPFE vs. IPF and evaluate their effect on clinical outcomes. Methods Comprehensive clinical data from CPFE and IPF patients were retrospectively reviewed. Baseline characteristics including lung function data, oxygen requirements, and pulmonary hemodynamics, were collected. Acute exacerbation events in both groups were defined clinically and radiographically. In the CPFE group, two patterns of exacerbations were identified. AE-COPD was defined clinically by symptoms of severe airflow obstruction causing respiratory failure and requiring hospitalization. Radiographic data were also defined based on previously published literature. AE-IPF was defined clinically as an acute hypoxic respiratory failure, requiring hospitalization and treatment with high dose corticosteroids. Radiographically, patients had to have a change in baseline imaging including presence of ground-glass opacities, interlobular septal thickening or new consolidations; that is not fully explained by other etiologies. Results Eighty-five CPFE patients were retrospectively compared to 112 IPF patients. Of 112 patients with IPF; 45 had AE-IPF preceding lung transplant (40.18%) compared to 12 patients in the CPFE group (14.1%) (p Conclusions CPFE patients may experience either AE-IPF or AE-COPD. Patients with CPFE and AE-COPD had better outcomes, requiring less intensive therapy compared to patients with AE-IPF regardless if underlying CPFE or IPF was present. These data suggest that the type of acute exacerbation, AE-COPD vs AE-IPF, has important implications for the treatment and prognosis of patients with CPFE.

Contains fulltext : 220761.pdf (Publisher’s version ) (Open Access) Rationale: The decades-long progression of chronic obstructive pulmonary disease (COPD) renders identifying different trajectories of disease progression challenging.Objectives: To identify subtypes of patients with COPD with distinct longitudinal progression patterns using a novel machine-learning tool called "Subtype and Stage Inference" (SuStaIn) and to evaluate the utility of SuStaIn for patient stratification in COPD.Methods: We applied SuStaIn to cross-sectional computed tomography imaging markers in 3,698 Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1-4 patients and 3,479 controls from the COPDGene (COPD Genetic Epidemiology) study to identify subtypes of patients with COPD. We confirmed the identified subtypes and progression patterns using ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) data. We assessed the utility of SuStaIn for patient stratification by comparing SuStaIn subtypes and stages at baseline with longitudinal follow-up data.Measurements and Main Results: We identified two trajectories of disease progression in COPD: a "Tissue-->Airway" subtype (n = 2,354, 70.4%), in which small airway dysfunction and emphysema precede large airway wall abnormalities, and an "Airway-->Tissue" subtype (n = 988, 29.6%), in which large airway wall abnormalities precede emphysema and small airway dysfunction. Subtypes were reproducible in ECLIPSE. Baseline stage in both subtypes correlated with future FEV1/FVC decline (r = -0.16 [P < 0.001] in the Tissue-->Airway group; r = -0.14 [P = 0.011] in the Airway-->Tissue group). SuStaIn placed 30% of smokers with normal lung function at elevated stages, suggesting imaging changes consistent with early COPD. Individuals with early changes were 2.5 times more likely to meet COPD diagnostic criteria at follow-up.Conclusions: We demonstrate two distinct patterns of disease progression in COPD using SuStaIn, likely representing different endotypes. One third of healthy smokers have detectable imaging changes, suggesting a new biomarker of "early COPD."

The purpose of this article is to review the high-resolution CT characteristics of individual obstructive and restrictive chronic lung allograft dysfunction (CLAD) phenotypes to aid in making accurate diagnoses and guiding treatment.Long-term survival and function after lung transplant are considerably worse compared with after other organ transplants. CLAD is implicated as a major limiting factor for long-term graft viability. Historically thought to be a single entity, bronchiolitis obliterans syndrome, CLAD is actually a heterogeneous group of disorders with distinct subtypes.

Contains fulltext : 194255.pdf (Publisher’s version ) (Open Access) BACKGROUND: Emphysema has considerable variability in its regional distribution. Craniocaudal emphysema distribution is an important predictor of the response to lung volume reduction. However, there is little consensus regarding how to define upper lobe-predominant and lower lobe-predominant emphysema subtypes. Consequently, the clinical and genetic associations with these subtypes are poorly characterized. METHODS: We sought to identify subgroups characterized by upper-lobe or lower-lobe emphysema predominance and comparable amounts of total emphysema by analyzing data from 9,210 smokers without alpha-1-antitrypsin deficiency in the Genetic Epidemiology of COPD (COPDGene) cohort. CT densitometric emphysema was measured in each lung lobe. Random forest clustering was applied to lobar emphysema variables after regressing out the effects of total emphysema. Clusters were tested for association with clinical and imaging outcomes at baseline and at 5-year follow-up. Their associations with genetic variants were also compared. RESULTS: Three clusters were identified: minimal emphysema (n = 1,312), upper lobe-predominant emphysema (n = 905), and lower lobe-predominant emphysema (n = 796). Despite a similar amount of total emphysema, the lower-lobe group had more severe airflow obstruction at baseline and higher rates of metabolic syndrome compared with subjects with upper-lobe predominance. The group with upper-lobe predominance had greater 5-year progression of emphysema, gas trapping, and dyspnea. Differential associations with known COPD genetic risk variants were noted. CONCLUSIONS: Subgroups of smokers defined by upper-lobe or lower-lobe emphysema predominance exhibit different functional and radiological disease progression rates, and the upper-lobe predominant subtype shows evidence of association with known COPD genetic risk variants. These subgroups may be useful in the development of personalized treatments for COPD.

Rationale: The American Thoracic Society (ATS)/European Respiratory Society defines a positive bronchodilator response (BDR) by a composite of BDR in either forced expiratory volume in 1 second (FEV(1)) and/or forced vital capacity (FVC) greater than or equal to 12% and 200 ml (ATS-BDR). We hypothesized that ATS-BDR components would be differentially associated with important chronic obstructive pulmonary disease (COPD) outcomes. Objectives: To examine whether ATS-BDR components are differentially associated with clinical, functional, and radiographic features in COPD. Methods: We included subjects with COPD enrolled in the COPDGene study. In the main analysis, we excluded subjects with self-reported asthma. We categorized BDR into the following: 1) No-BDR, no BDR in either FEV(1) or FVC; 2) FEV(1)-BDR, BDR in FEV(1) but no BDR in FVC; 3) FVC-BDR, BDR in FVC but no BDR in FEV(1); and 4) Combined-BDR, BDR in both FEV(1) and FVC. We constructed multivariable logistic, linear, zero-inflated negative binomial, and Cox hazards models to examine the association of BDR categories with symptoms, computed tomography findings, change in FEV(1) over time, respiratory exacerbations, and mortality. We also created models using the ATS BDR definition (ATS-BDR) as the main independent variable. Results: Of 3,340 COPD subjects included in the analysis, 1,083 (32.43%) had ATS-BDR, 182 (5.45%) had FEV(1)-BDR, 522 (15.63%) had FVC-BDR, and 379 (11.34%) had Combined-BDR. All BDR categories were associated with FEV(1) decline compared with No-BDR. Compared with No-BDR, both ATS-BDR and Combined-BDR were associated with higher functional residual capacity %predicted, greater internal perimeter of 10 mm, and greater 6-minute-walk distance. In contrast to ATS-BDR, Combined-BDR was independently associated with less emphysema (adjusted beta regression coefficient, −1.67; 95% confidence interval [CI], −2.68 to −0.65; P = 0.001), more frequent respiratory exacerbations (incidence rate ratio, 1.25; 95% CI, 1.03–1.50; P = 0.02) and severe exacerbations (incidence rate ratio, 1.34; 95% CI, 1.05–1.71; P = 0.02), and lower mortality (adjusted hazards ratio, 0.76; 95% CI, 0.58–0.99; P = 0.046). Sensitivity analysis that included subjects with self-reported history of asthma showed similar findings. Conclusions: BDR in both FEV(1) and FVC indicates a COPD phenotype with asthma-like characteristics, and provides clinically more meaningful information than current definitions of BDR.

Background Chronic bronchitis (CB) increases risk of COPD exacerbations. We have shown that the St. George's Respiratory Questionnaire (SGRQ) CB definition identifies patients with a similar clinical phenotype as classically defined CB. Whether the SGRQ CB definition is a predictor of future COPD exacerbations is unknown. Methods We analyzed 7,557 smokers with normal spirometry and Global Initiative for Chronic Obstructive Lung Disease stage 1-4 COPD in the Genetic Epidemiology of COPD study with longitudinal follow-up data on exacerbations. Subjects were divided into classic CB+ or classic CB–, using the classic definition. In addition, subjects were divided into SGRQ CB+ or SGRQ CB–. Exacerbation frequency and severe exacerbation frequency were determined in each group. Multivariable linear regressions were performed for exacerbation frequency with either classic CB or SGRQ CB and relevant covariates. Results There were 1,434 classic CB+ subjects and 2,290 SGRQ CB+ subjects. The classic CB+ group had a greater exacerbation frequency compared with the classic CB– group (0.69 ± 1.26 vs 0.36 ± 0.90 exacerbations per patient per year; P Conclusions The SGRQ CB definition identified more subjects at risk for future exacerbations than the classic CB definition. SGRQ CB was at least a similar if not better predictor of future exacerbations than classic CB.

Background: The aetiology and inflammatory profile of combined pulmonary fibrosis and emphysema (CPFE) remain uncertain currently. Objective: We aimed to examine the levels of inflammatory proteins in lung tissue in a cohort of patients with emphysema, interstitial pulmonary fibrosis (IPF), and CPFE. Materials and methods: Explanted lungs were obtained from subjects with emphysema, IPF, CPFE, (or normal subjects), and tissue extracts were prepared. Thirty-four inflammatory proteins were measured in each tissue section. Results: The levels of all 34 proteins were virtually indistinguishable in IPF compared with CPFE tissues, and collectively, the inflammatory profile in the emphysematous tissues were distinct from IPF and CPFE. Moreover, inflammatory protein levels were independent of the severity of the level of diseased tissue. Conclusions: We find that emphysematous lung tissues have a distinct inflammatory profile compared with either IPF or CPFE. However, the inflammatory profile in CPFE lungs is essentially identical to lungs from patients with IPF. These data suggest that distinct inflammatory processes collectively contribute to the disease processes in patients with emphysema, when compared to IPF and CPFE.

The purpose of this article is to review the normal postoperative appearance of various sternotomy configurations as well as the pathophysiologic and imaging characteristics of sternotomy complications on radiographs, MDCT, MRI, and scintigraphy.Clinical signs of sternotomy complications are nonspecific and often overlap with normal postoperative changes. Knowledge of normal and abnormal imaging findings is essential to guide management and treatment.

BackgroundCOPD is associated with cardiovascular disease (CVD), and coronary artery calcification (CAC) provides additional prognostic information. With increasing use of nongated CT scans in clinical practice, this study hypothesized that the visual Weston CAC score would perform as well as the Agatston score in predicting prevalent and incident coronary artery disease (CAD) and CVD in COPD.MethodsCAC was measured by using Agatston and Weston scores on baseline CT scans in 1,875 current and former smokers enrolled in the Genetic Epidemiology of COPD (COPDGene) study. Baseline cardiovascular disease and incident cardiac events on longitudinal follow-up were recorded. Accuracy of the CAC scores was measured by using receiver-operating characteristic analysis, and Cox proportional hazards analyses were used to estimate the risk of incident cardiac events.ResultsCAD was reported by 133 (7.1%) subjects at baseline. A total of 413 (22.0%) and 241 (12.9%) patients had significant CAC according to the Weston (≥ 7) and Agatston (≥ 400) scores, respectively; the two methods were significantly correlated (r= 0.84; P< .001). Over 5 years of follow-up, 127 patients (6.8%) developed incident CVD. For predicting prevalent CAD, c-indices for the Weston and Agatston scores were 0.78 and 0.74 and for predicting incident CVD, they were 0.62 and 0.61. After adjustment for age, race, sex, smoking pack-years, FEV1, percent emphysema, and CT scanner type, a Weston score≥ 7 was associated with time to first acute coronary event (hazard ratio, 2.16 [95%CI, 1.32 to 3.53]; P= .002), but a Agatston score≥ 400 was not (hazard ratio, 1.75 [95%CI, 0.99-3.09]; P= .053).ConclusionsA simple visual score for CAC performed well in predicting incident CAD in smokers with and without COPD.Trial registryClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.

BACKGROUND:Eosinophilic airway inflammation in patients with chronic obstructive pulmonary disease (COPD) is associated with exacerbations and responsivity to steroids, suggesting potential shared mechanisms with eosinophilic asthma. However, there is no consistent blood eosinophil count that has been used to define the increased exacerbation risk. OBJECTIVE:We sought to investigate blood eosinophil counts associated with exacerbation risk in patients with COPD. METHODS:Blood eosinophil counts and exacerbation risk were analyzed in patients with moderate-to-severe COPD by using 2 independent studies of former and current smokers with longitudinal data. The Genetic Epidemiology of COPD (COPDGene) study was analyzed for discovery (n=1,553), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study was analyzed for validation (n=1,895). Asubset of the ECLIPSE study subjects were used to assess the stability of blood eosinophil counts over time. RESULTS:COPD exacerbation risk increased with higher eosinophil counts. An eosinophil count threshold of 300cells/μL or greater showed adjusted incidence rate ratios for exacerbations of 1.32 in the COPDGene study (95% CI, 1.10-1.63). The cutoff of 300cells/μL or greater was validated for prospective risk of exacerbation in the ECLIPSE study, with adjusted incidence rate ratios of 1.22 (95% CI, 1.06-1.41) using 3-year follow-up data. Stratified analysis confirmed that the increased exacerbation risk associated with an eosinophil count of 300cells/μL or greater was driven by subjects with a history of frequent exacerbations in both the COPDGene and ECLIPSE studies. CONCLUSIONS:Patients with moderate-to-severe COPD and blood eosinophil counts of 300cells/μL or greater had an increased risk exacerbations in the COPDGene study, which was prospectively validated in the ECLIPSE study.

The normal aortic arch branching pattern is of a three-vessel arch with the vertebral arteries arising from the subclavian arteries. There are a variety of well-known symptomatic and asymptomatic aortic branching patterns widely reported in the literature. An anomalous right vertebral artery with a diverticulum of Kommerell is an extremely rare variant, with few other cases reported in the literature. Herein, we review the embryology of the aortic arch and vertebral artery, the various types of Kommerell's diverticula and the clinical significance of this anomaly.

Background Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) has an expected median survival of 3 months. Lung transplantation is a potentially lifesaving therapy for AE-IPF. However, the current knowledge of transplantation outcomes during AE-IPF is limited to a few small retrospective studies, reporting only 1-year post-transplantation survival. Methods Study population included patients with IPF consecutively listed for lung transplantation at a single institution between the years 2012 and 2016. We collected lung allocation score (LAS), hospitalization, and survival data. The primary outcome was survival among patients transplanted during stable IPF vs during AE-IPF. Results Of 89 patients with IPF listed for lung transplantation, 52 were transplanted during stable IPF and 37 were hospitalized due to AE-IPF. Of these 37 patients, nine died before transplantation, and 28 were transplanted during AE-IPF. Fifty percent of patients transplanted during AE-IPF died in a mean follow-up of 1.6 ± 1.2 years compared with 12% of patients transplanted during stable IPF who died in a mean follow-up of 2.6 ± 1.2 years. The Kaplan-Meier survival curves post-transplantation after 1 and 3 years for patients who were transplanted during stable IPF were 94% and 90% vs 71% and 60% in patients who were transplanted during AE-IPF (P = .0001). LAS above 80 conferred a 3-year hazard ratio for mortality of 5.7 vs LAS lower than 80 (95% CI, 2.33-14.0; P Conclusions Patients with IPF transplanted during AE-IPF had significantly worse short-term and long-term survival compared with patients transplanted during stable IPF. Patients with AE-IPF and very high LAS may not experience the survival advantage expected from lung transplantation.

The proven success of endoscopic and videoscopic surgery combined with recent advancements in telemanipulation has made the performance of minimally invasive cardiac surgery a clinical reality during the past decade. A complete understanding of the basic concepts of minimally invasive surgery and the recent advancements in peripheral cardiopulmonary bypass techniques help the cardiac imager to provide a clinically meaningful interpretation for the surgical team. In this article we present an overview of minimally invasive mitral valve surgery and the fundamentals of preprocedural computed tomography angiography imaging and highlight the usefulness of cardiac computed tomography as a supplementary tool to echocardiography.

Background Pulmonary thromboendarterectomy (PTE) is the treatment of choice for eligible patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, access to CTEPH and PTE care is limited. There is a paucity of published data on PTE efficacy and outcomes from alternative, regional centers of excellence in CTEPH and PTE care in the USA, outside a single national and international referral center. Methods We performed a retrospective review of patients undergoing PTE at our institution from June 2013 to December 2016 (42 months), and collected clinical, echocardiographic and hemodynamic data on our patients pre- and post-PTE (N.=71). Results Patients age ranged between 20-83 years (mean±SD: 56±16), with 54% of patients female and 61% Caucasians. The predominant symptom was shortness of breath with a median duration of symptoms of 17 months. Following PTE, clinical improvements included a reduction in NYHA class from 3.1±1.1 to 2.2±1.2. There were major improvements in hemodynamics and echocardiographic parameters pre- versus post-PTE: mean pulmonary artery pressure (mmHg) 45±11 to 24±8, cardiac index (L/min/m2) 2.1±0.5 to 2.8±0.5, pulmonary vascular resistance (mmHg/L/min) 8.9±4.5 to 2.8±1.8, ratio of right ventricle (RV): left ventricle (LV) 1.2±0.3 to 0.9±0.2, RV fractional area change (%) 23±14 to 44±13, reduction in the incidence of RV outflow tract Doppler notching and improved pulmonary artery acceleration time (96% to 30%, and 74±19 to 111±21). In-hospital mortality was 4.2% (3 patients). Conclusions Herein, we report for the first time, the improvements in patient functionality, hemodynamics, right heart function and outcomes at a major regional PTE program.

The heritability of chronic obstructive pulmonary disease (COPD) cannot be fully explained by recognized genetic risk factors identified as achieving genome-wide significance. In addition, the combined contribution of genetic variation to COPD risk has not been fully explored. We sought to determine: (1) whether studies of variants from previous studies of COPD or lung function in a larger sample could identify additional associated variants, particularly for severe COPD; and (2) the impact of genetic risk scores on COPD. We genotyped 3,346 single-nucleotide polymorphisms (SNPs) in 2,588 cases (1,803 severe COPD) and 1,782 control subjects from four cohorts, and performed association testing with COPD, combining these results with existing genotyping data from 6,633 cases (3,497 severe COPD) and 5,704 control subjects. In addition, we developed genetic risk scores from SNPs associated with lung function and COPD and tested their discriminatory power for COPD-related measures. We identified significant associations between SNPs near PPIC (P = 1.28 X 10(-8)) and PPP4R4/SERPINA1 (P = 1.01 X 10(-8)) and severe COPD; the latter association may be driven by recognized variants in SERPINA1. Genetic risk scores based on SNPs previously associated with COPD and lung function had a modest ability to discriminate COPD (area under the curve, similar to 0.6), and accounted for a mean 0.9-1.9% lower forced expiratory volume in 1 second percent predicted for each additional risk allele. In a large genetic association analysis, we identified associations with severe COPD near PPIC and SERPINA1. A risk score based on combining genetic variants had modest, but significant, effects on risk of COPD and lung function.

RationaleThe demographic, physiological, and computed tomography (CT) features associated with pneumothorax in smokers with and without chronic obstructive pulmonary disease (COPD) are not clearly defined.ObjectivesWe evaluated the hypothesis that pneumothorax in smokers is associated with male sex, tall and thin stature, airflow obstruction, and increased total and subpleural emphysema.MethodsThe study included smokers with and without COPD from the COPDGene Study, with quantitative chest CT analysis. Pleural-based emphysema was assessed on the basis of local histogram measures of emphysema. Pneumothorax history was defined by subject self-report.Measurements and main resultsPneumothorax was reported in 286 (3.2%) of 9,062 participants. In all participants, risk of prior pneumothorax was significantly higher in men (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.08-2.22) and non-Hispanic white subjects (OR, 1.90; 95% CI, 1.34-2.69). Risk of prior pneumothorax was associated with increased percent CT emphysema in all participants and participants with COPD (OR, 1.04 for each 1% increase in emphysema; 95% CI, 1.03-1.06). Increased pleural-based emphysema was independently associated with risk of past pneumothorax in all participants (OR, 1.05 for each 1% increase; 95% CI, 1.01-1.10). In smokers with normal spirometry, risk of past pneumothorax was associated with non-Hispanic white race and lifetime smoking intensity (OR, 1.20 for every 10 pack-years; 95% CI, 1.09-1.33).ConclusionsAmong smokers, pneumothorax is associated with male sex, non-Hispanic white race, and increased percentage of total and subpleural CT emphysema. Pneumothorax was not independently associated with height or lung function, even in participants with COPD. Clinical trial registered with www.clinicaltrials.gov (NCT00608764).

BACKGROUND The risk factors for acute episodes of respiratory disease in current and former smokers who do not have COPD are unknown. METHODS Eight thousand two hundred forty-six non-Hispanic white and black current and former smokers in the Genetic Epidemiology of COPD (COPDGene) cohort had longitudinal follow-up (LFU) every 6 months to determine acute respiratory episodes requiring antibiotics or systemic corticosteroids, an ED visit, or hospitalization. Negative binomial regression was used to determine the factors associated with acute respiratory episodes. A Cox proportional hazards model was used to determine adjusted hazard ratios (HRs) for time to first episode and an acute episode of respiratory disease risk score. RESULTS At enrollment, 4,442 subjects did not have COPD, 658 had mild COPD, and 3,146 had moderate or worse COPD. Nine thousand three hundred three acute episodes of respiratory disease and 2,707 hospitalizations were reported in LFU (3,044 acute episodes of respiratory disease and 827 hospitalizations in those without COPD). Major predictors included acute episodes of respiratory disease in year prior to enrollment (HR, 1.20; 95% CI, 1.15-1.24 per exacerbation), airflow obstruction (HR, 0.94; 95% CI, 0.91-0.96 per 10% change in % predicted FEV 1 ), and poor health-related quality of life (HR, 1.07; 95% CI, 1.06-1.08 for each 4-unit increase in St. George's Respiratory Questionnaire score). Risks were similar for those with and without COPD. CONCLUSIONS Although acute episode of respiratory disease rates are higher in subjects with COPD, risk factors are similar, and at a population level, there are more episodes in smokers without COPD.

The real-world tolerability of pirfenidone and nintedanib in non-clinical trial patients is unknown. Many patients with pulmonary fibrosis have significant medical co-morbidities or baseline characteristics that exclude them from clinical trial participation.We conducted a retrospective chart review study on subjects prescribed nintedanib or pirfenidone for pulmonary fibrosis treatment (any aetiology) from September 2014 to February 2016. A total of 186 subjects were included: 129 received pirfenidone and 57 were prescribed nintedanib and followed up for mean observation periods of 52 ± 17 weeks for pirfenidone and 41 ± 15 weeks for nintedanib. The primary outcome was drug discontinuation as a result of an adverse event.Subjects had significant respiratory impairment at baseline, 63% required home oxygen therapy and mean diffusion capacity of carbon monoxide (DLCO) was 36 ± 14% predicted. Drug discontinuation as a result of an adverse event occurred in 20.9% of subjects on pirfenidone and 26.3% on nintedanib. Drug discontinuation rates for both pirfenidone and nintedanib did not significantly differ from corresponding large clinical trials (ASCEND/CAPACITY and INPULSIS 1 and 2, respectively). Adverse events that occurred with highest frequency on pirfenidone were nausea (26.4%), rash/photosensitivity (14.7%) and dyspepsia/gastroesophageal reflux disease (GERD) (12.4%). Diarrhoea (52.6%) and nausea (29.8%) were reported most often with nintedanib therapy.Patients with pulmonary fibrosis treated with nintedanib or pirfenidone in routine clinical practice had drug tolerability and adverse event profiles comparable with subjects enrolled in clinical trials despite having a greater degree of respiratory impairment and a high prevalence of co-morbid medical conditions.

The value of quantitative CT (QCT) to identify chronic obstructive pulmonary disease (COPD) phenotypes is increasingly appreciated. The authors hypothesised that QCT-defined emphysema and airway abnormalities relate to St George's Respiratory Questionnaire (SGRQ) and Body-Mass Index, Airflow Obstruction, Dyspnea and Exercise Capacity Index (BODE).1200 COPDGene subjects meeting Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD with QCT analysis were included. Total lung emphysema was measured using the density mask technique with a -950 Hounsfield unit threshold. An automated programme measured mean wall thickness (WT), wall area percentage (WA%) and 10 mm lumenal perimeter (pi10) in six segmental bronchi. Separate multivariate analyses examined the relative influence of airway measures and emphysema on SGRQ and BODE.In separate models predicting SGRQ score, a 1 unit SD increase in each airway measure predicted higher SGRQ scores (for WT, 1.90 points higher, p=0.002; for WA%, 1.52 points higher, p=0.02; for pi10, 2.83 points higher p0.001). The comparable increase in SGRQ for a 1 unit SD increase in emphysema percentage in these models was relatively weaker, significant only in the pi10 model (for emphysema percentage, 1.45 points higher, p=0.01). In separate models predicting BODE, a 1 unit SD increase in each airway measure predicted higher BODE scores (for WT, 1.07-fold increase, p0.001; for WA%, 1.20-fold increase, p0.001; for pi10, 1.16-fold increase, p0.001). In these models, emphysema more strongly influenced BODE (range 1.24-1.26-fold increase, p0.001).Emphysema and airway disease both relate to clinically important parameters. The relative influence of airway disease is greater for SGRQ; the relative influence of emphysema is greater for BODE.

The purposes of this study were: to describe chest CT findings in normal nonsmoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring. Methods: Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9-11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements. Results: Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively. Conclusions: Despite substantial interobserver variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.

Background Cigarette smoking is a major risk factor for chronic obstructive pulmonary disease (COPD) and COPD severity. Previous genome-wide association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) associated with the number of cigarettes smoked per day (CPD) and a dopamine beta-hydroxylase (DBH) locus associated with smoking cessation in multiple populations. Objective To identify SNPs associated with lifetime average and current CPD, age at smoking initiation, and smoking cessation in patients with COPD. Methods GWAS were conducted in four independent cohorts encompassing 3441 ever-smoking patients with COPD (Global Initiative for Obstructive Lung Disease stage II or higher). Untyped SNPs were imputed using the HapMap (phase II) panel. Results from all cohorts were meta-analysed. Results Several SNPs near the HLA region on chromosome 6p21 and in an intergenic region on chromosome 2q21 showed associations with age at smoking initiation, both with the lowest p=2x10(-7). No SNPs were associated with lifetime average CPD, current CPD or smoking cessation with p

Accurate measurement of esophageal hiatus size is clinically important, especially when antireflux surgery is planned. We present a novel method for in vivo measurement of esophageal hiatal surface area using MDCT multiplanar reconstruction. We aimed to determine whether large hiatal area is associated with hiatal hernia and gastroesophageal reflux disease.We retrospectively analyzed subjects prospectively enrolled in the COPDGene(®) project. We created two test groups, one with hiatal hernia on chest CT and one with GERD on medical treatment identified by history without hernia. Matched control groups were formed. We performed CT postprocessing to define the double-oblique plane of the esophageal hiatus, on which the hiatal surface area is manually traced.Subjects with hernia (n = 48) had larger mean hiatus areas than matched controls (6.9 vs. 2.5 cm(2), p 0.0001), and were more likely to have GERD (42 vs. 10 %, p 0.0005). Subjects with mixed (type III) hernias had larger hiatuses compared to subjects with sliding (type I) hernias, who, in turn, had larger hiatuses than subjects without hernia (p 0.0001). Hernia-negative subjects with GERD (n = 55) did not have significantly larger mean hiatal areas compared to matched controls (3.0 vs. 2.5 cm(2), p = 0.12). Twenty measurements obtained by two radiologists showed correlation of 0.93, with mean difference of 0.5 cm(2) (p = 0.20).We devised a method to measure in vivo esophageal hiatal surface area using MDCT reconstruction and established the normal size range for the first time. This methodology has the potential to guide decision-making in antireflux surgery technique preoperatively, and assess surgical result postoperatively. The presence of hernia correlated with large hiatuses and GERD. However, hiatal area failed to identify those with GERD in the absence of hiatal hernia.

To determine whether computer-aided detection (CAD) applied to computed tomographic (CT) colonography can help improve sensitivity of polyp detection by less-experienced radiologist readers, with colonoscopy or consensus used as the reference standard.The release of the CT colonographic studies was approved by the individual institutional review boards of each institution. Institutions from the United States were HIPAA compliant. Written informed consent was waived at all institutions. The CT colonographic studies in 30 patients from six institutions were collected; 24 images depicted at least one confirmed polyp 6 mm or larger (39 total polyps) and six depicted no polyps. By using an investigational software package, seven less-experienced readers from two institutions evaluated the CT colonographic images and marked or scored polyps by using a five-point scale before and after CAD. The time needed to interpret the CT colonographic findings without CAD and then to re-evaluate them with CAD was recorded. For each reader, the McNemar test, adjusted for clustered data, was used to compare sensitivities for readers without and with CAD; a Wilcoxon signed-rank test was used to analyze the number of false-positive results per patient.The average sensitivity of the seven readers for polyp detection was significantly improved with CAD-from 0.810 to 0.908 (P=.0152). The number of false-positive results per patient without and with CAD increased from 0.70 to 0.96 (95% confidence interval for the increase: -0.39, 0.91). The mean total time for the readings was 17 minutes 54 seconds; for interpretation of CT colonographic findings alone, the mean time was 14 minutes 16 seconds; and for review of CAD findings, the mean time was 3 minutes 38 seconds.Results of this feasibility study suggest that CAD for CT colonography significantly improves per-polyp detection for less-experienced readers.

A cDNA clone, representing the mouse homologue of the recently described gene encoding the human calcium signal-modulating ligand, was isolated from a mouse thymus library. This clone exhibits extensive conservation of the primary nucleotide and deduced amino-acid sequences that, when considered with a similar secondary protein structure, transcript size and distribution of expression, suggests a similarity in function.