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Prognostic Models in Pulmonary Embolism

Background:This study aimed to assess the performance of two prognostic models—the European Society of Cardiology (ESC) model and the simplified Pulmonary Embolism Severity Index (sPESI)—in predicting short-term mortality in patients with pulmonary embolism (PE).Methods:We compared the test characteristics of the ESC model and the sPESI for predicting 30-day outcomes in a cohort of 526 patients with objectively confirmed PE. The primary end point of the study was all-cause mortality. The secondary end point included all-cause mortality, nonfatal symptomatic recurrent VTE, or nonfatal major bleeding.Results:Overall, 40 of 526 patients died (7.6%; 95% CI, 5.3%-9.9%) during the first month of follow-up. The sPESI classified fewer patients as low risk (31% [165 of 526], 95% CI, 27%-35%) compared with the ESC model (39% [207 of 526], 95% CI, 35% to 44%; P < .01). Importantly however, low-risk patients based on the sPESI had no 30-day mortality compared with 3.4% (95% CI, 0.9-5.8) in low-risk patients by the ESC model. The secondary end point occurred in 1.8% of patients in the sPESI low-risk and 5.8% in the ESC low-risk group (difference, 4.0 percentage points; 95% CI, 0.2-7.8). The prognostic ability of the ESC model remained significant in the subgroup of patients at high-risk according to the sPESI model (OR 1.95, 95% CI, 1.41 to 2.71, P < .001).Conclusions:Both the sPESI and the ESC model successfully predict 30-day mortality after acute symptomatic PE, but exclusion of an adverse early outcome does not appear to require routine imaging procedures or laboratory biomarker testing.

Obesity-Associated Asthma in Children

Obesity-associated asthma has been proposed to be a distinct entity, differing in immune pathogenesis from atopic asthma. Both obesity-mediated inflammation and increase in adiposity are potential mechanistic factors that are poorly defined among children.

We hypothesized that pediatric obesity-associated asthma would be characterized by T helper (Th) 1, rather than the Th2 polarization associated with atopic asthma. Moreover, we speculated that Th1 biomarkers and anthropometric measures would correlate with pulmonary function tests (PFTs) in obese asthmatic children.

Methods : We recruited 120 children, with 30 in each of the four study groups: obese asthmatic children, nonobese asthmatic children, obese nonasthmatic children, and nonobese nonasthmatic children. All children underwent pulmonary function testing. Blood was collected for measurement of serum cytokines. T-cell responses to mitogen, phorbol 12-myristate 13-acetate (PMA), or antigens tetanus toxoid or Dermatophagoides farinae were obtained by flow cytometric analysis of intracellular cytokine staining for interferon-γ (IFN-γ) (Th1) or IL-4 (Th2) within the CD4 population.

Results : Obese asthmatic children had significantly higher Th1 responses to PMA (P < .01) and tetanus toxoid (P < .05) and lower Th2 responses to PMA (P < .05) and D farinae (P < .01) compared with nonobese asthmatic children. Th-cell patterns did not differ between obese asthmatic children and obese nonasthmatic children. Obese asthmatic children had lower FEV1/FVC (P < .01) and residual volume/total lung capacity ratios (P < .005) compared with the other study groups, which negatively correlated with serum interferon-inducible protein 10 and IFN-γ levels, respectively. PFTs, however, did not correlate with BMI z score or waist to hip ratio.

Conclusions : We found that pediatric obesity-associated asthma differed from atopic asthma and was characterized by Th1 polarization. The altered immune environment inversely correlated with PFTs in obese asthmatic children.

Predictors of 6-Min Walk Distance in Smokers

Exercise tolerance in COPD is only moderately well predicted by airflow obstruction assessed by FEV1. We determined whether other phenotypic characteristics, including CT scan measures, are independent predictors of 6-min walk distance (6MWD) in the COPDGene cohort.

Methods : COPDGene recruits non-Hispanic Caucasian and African American current and ex-smokers. Phenotyping measures include postbronchodilator FEV1 % predicted and inspiratory and expiratory CT lung scans. We defined % emphysema as the percentage of lung voxels < −950 Hounsfield units on the inspiratory scan and % gas trapping as the percentage of lung voxels < −856 Hounsfield units on the expiratory scan.

Results : Data of the first 2,500 participants of the COPDGene cohort were analyzed. Participant age was 61 ± 9 years; 51% were men; 76% were non-Hispanic Caucasians, and 24% were African Americans. Fifty-six percent had spirometrically defined COPD, with 9.3%, 23.4%, 15.0%, and 8.3% in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV, respectively. Higher % emphysema and % gas trapping predicted lower 6MWD (P < .001). However, in a given spirometric group, after adjustment for age, sex, race, and BMI, neither % emphysema nor % gas trapping, or their interactions with FEV1 % predicted, remained a significant 6MWD predictor. In a given spirometric group, only 16% to 27% of the variance in 6MWD could be explained by age, male sex, Caucasian race, and lower BMI as significant predictors of higher 6MWD.

Conclusions : In this large cohort of smokers in a given spirometric stage, phenotypic characteristics were only modestly predictive of 6MWD. CT scan measures of emphysema and gas trapping were not predictive of 6MWD after adjustment for other phenotypic characteristics.

Pulmonary Function Interpretation Practices

Because many different reference equations are available for pulmonary function testing (PFT), and because different interpretive strategies could affect the interpretation of results, we assessed the variation in practice among 17 PFT laboratories.

Methods : PFT laboratory directors/supervisors in 17 hospitals (near Cleveland, Ohio) were surveyed between September 15, 2010, and January 5, 2011. The survey assessed the features of the laboratory, including equipment used, types of tests offered, volume of testing, reference equations used, and interpretive strategies employed (eg, how normal was determined, how tests were actually read, and so forth).

Results : Responses were received from all 17 laboratories and were verified using submitted sample PFT reports. The daily median number of tests performed and patients evaluated were 16 and six, respectively. Great variation was observed not only in the choice of reference equations for spirometry, but also in the criteria used to define airflow obstruction. Great variation was also observed in the reference equations used for lung volumes and diffusing capacity, as well as in the criteria used to define physiologic derangements such as restriction, hyperinflation, air trapping, and impaired diffusing capacity. Only three of the 17 laboratories reported and used the “lower limit of normal” to define PFT abnormality.

Conclusions : This survey demonstrated substantial variation in PFT laboratory practices, including the choice of reference equations, the criteria used to define abnormality, and the strategies for interpreting tests. The degree of variation raises concern about the consistency of the interpretation of results among laboratories and emphasizes the value of compliance with official guidelines to drive standardization.

Asthma in pregnancy: are inhaled corticosteroids safe?

Authors: George J, Abramson MJ, Walker
SP Source: American Journal of Respiratory and Critical Care Medicine)

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