James Wells

Determinants of arterial stiffness in COPD

BackgroundCardiovascular morbidity and mortality is high in patients with chronic obstructive pulmonary disease (COPD) and arterial stiffness is a potentially modifiable risk factor with added predictive value beyond that obtained from traditional risk factors. Arterial stiffness has been the target of pharmacologic and exercise interventions in patients with COPD, but the effects appear limited to those patients with more significant elevations in arterial stiffness. We aimed to identify predictors of increased arterial stiffness in a cohort with moderate to severe COPD.MethodsAortic pulse wave velocity (aPWV) was measured in subjects with moderate to severe COPD enrolled in a multicenter randomized controlled trial. Subjects were categorized into quartiles based on aPWV values and factors affecting high arterial stiffness were assessed. Multivariate models were created to identify independent predictors of high aPWV, and cardiovascular disease (CVD).Results153 patients were included. Mean age was 63.2 (SD 8.2) years and mean FEV1 was 55.4 (SD 15.2) % predicted. Compared to the quartile with the lowest aPWV, subjects in the highest quartile were older, had higher systolic blood pressure (SBP), were more likely to be current smokers, and had greater burden of thoracic aortic calcification. On multivariate analyses, age (adjusted OR 1.14, 95%CI 1.05 to 1.25, p = 0.003) and SBP (adjusted OR 1.06, 95% CI 1.02 to 1.09, p = 0.001) were independent predictors of elevated aPWV. Body mass index, therapy with cholesterol lowering medications and coronary calcification were independent predictors of CVD.ConclusionsElevated arterial stiffness in patients with COPD can be predicted using age, blood pressure and thoracic aortic calcification. This will help identify subjects for enrollment in clinical trials using aPWV for assessing the impact of COPD therapies on CV outcomes.Trial registrationClinicaltrials.gov NCT00857766

Pathophysiology and clinical implications of pulmonary arterial enlargement in COPD

Chronic obstructive pulmonary disease (COPD) is a complex condition defined by progressive airflow limitation in response to noxious stimuli, inflammation, and vascular changes. COPD exacerbations are critical events in the natural history of the disease, accounting for the majority of disease burden, cost, and mortality. Pulmonary vascular disease is an important risk factor for disease progression and exacerbation risk. Relative pulmonary artery enlargement on computed tomography scan, defined by a pulmonary artery to aortic (PA:A) ratio >1, has been evaluated as a marker of pulmonary vascular disease. The PA:A ratio can be measured reliably independent of electrocardiographic gating or the use of contrast, and in healthy patients a PA:A ratio >0.9 is considered to be abnormal. The PA:A ratio has been compared with invasive hemodynamic parameters, primarily mean pulmonary artery pressure in various disease conditions and is more strongly correlated with mean pulmonary artery pressure in obstructive as compared with interstitial lung disease. In patients without known cardiac or pulmonary disease, the PA:A ratio is predictive of mortality, while in COPD, an elevated PA:A ratio is correlated with increased exacerbation risk, outperforming other well established predictors of these events. Future studies should be aimed at determining the stability of the metric over time and evaluating the utility of the PA:A ratio in guiding specific therapies.

β-Blockers are associated with a reduction in COPD exacerbations

Background While some retrospective studies have suggested that β-blocker use in patients with COPD is associated with a reduction in the frequency of acute exacerbations and lower mortality, there is concern that their use in patients with severe COPD on home oxygen may be harmful. Methods Subjects with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2–4 COPD participating in a prospective follow-up of the COPDGene cohort, a multicentre observational cohort of current and former smokers were recruited. Total and severe exacerbation rates were compared between groups categorised by β-blocker use on longitudinal follow-up using negative binomial regression analyses, after adjustment for demographics, airflow obstruction, %emphysema on CT, respiratory medications, presence of coronary artery disease, congestive heart failure and coronary artery calcification, and after adjustment for propensity to prescribe β-blockers. Results 3464 subjects were included. During a median of 2.1 years of follow-up, β-blocker use was associated with a significantly lower rate of total (incidence risk ratio (IRR) 0.73, 95% CI 0.60 to 0.90; p=0.003) and severe exacerbations (IRR 0.67, 95% CI 0.48 to 0.93; p=0.016). In those with GOLD stage 3 and 4 and on home oxygen, use of β-blockers was again associated with a reduction in the rate of total (IRR 0.33, 95% CI 0.19 to 0.58; p<0.001) and severe exacerbations (IRR 0.35, 95% CI 0.16 to 0.76; p=0.008). Exacerbation reduction was greatest in GOLD stage B. There was no difference in all-cause mortality with β-blocker use. Conclusions β-Blockers are associated with a significant reduction in COPD exacerbations regardless of severity of airflow obstruction. The findings of this study should be tested in a randomised, placebo-controlled trial. Trial registration number (ClinicalTrials.gov NCT00608764).

FEV(1)/FEV(6) to diagnose airflow obstruction. Comparisons with computed tomography and morbidity indices.

RATIONALE FVC is a difficult maneuver for many patients, and forced expiratory volume in 6 seconds (FEV6) has been proposed as a surrogate for FVC for the diagnosis of chronic obstructive pulmonary disease (COPD). Previous studies have performed head-to-head comparisons of these thresholds but did not examine their relationships with structural lung disease, symptoms, or exacerbations. OBJECTIVES To compare FEV1/FEV6 with FEV1/FVC in the diagnosis of COPD-related morbidity and structural lung disease as assessed by CT. METHODS We analyzed data from a large multicenter cohort study (COPDGene) that included current and former smokers (age 45-80 yr). Accuracy and concordance between the two ratios in diagnosing structural COPD was compared using CT measures of emphysema and airway disease and COPD-related morbidity to assess how the two ratios compare in defining disease. RESULTS A total of 10,018 subjects were included. FEV1/FEV6 showed excellent accuracy in diagnosing airflow obstruction using FEV1/FVC < 0.70 as a reference (area under curve, 0.99; 95% confidence interval [CI], 0.989-0.992; P < 0.001). FEV1/FEV6 < 0.73 had the best sum of sensitivity (92.1%; 95% CI, 90.8-92.4) and specificity (97.3%; 95% CI, 97.3-98.1). There was excellent agreement between the two diagnostic cutoffs (κ = 0.90; 95% CI, 0.80-0.91; P < 0.001). In comparison with control subjects and those positive by FEV1/FVC alone, subjects positive by FEV1/FEV6 alone had greater gas trapping and airway wall thickness, worse functional capacity, and a greater number of exacerbations on follow-up. These relationships held true when disease definitions were made using the lower limits of normal. CONCLUSIONS FEV1/FEV6 can be substituted for FEV1/FVC in diagnosing airflow obstruction and may better predict COPD-related pathology and morbidity.

Radiological correlates and clinical implications of the paradoxical lung function response to β2 agonists: an observational study

BACKGROUND Bronchodilator response has been noted in a significant proportion of patients with chronic obstructive pulmonary disease (COPD). However, there are also reports of a paradoxical response to β₂ agonists resulting in bronchoconstriction. Asymptomatic bronchoconstriction is likely to be far more common than is symptomatic bronchoconstriction with β₂ agonists, but no systematic studies have been done. We assessed the prevalence of paradoxical response in current and former smokers with and without COPD, and its radiological correlates and clinical implications. METHODS Non-Hispanic white and African-American patients (aged 45-80 years) from a large multicentre study COPDGene were classified into two groups on the basis of a paradoxical response, defined as at least a 12% and 200 mL reduction in forced expiratory volume in 1 sec (FEV₁) or forced vital capacity (FVC), or both, after administration of a shortacting β₂ agonist (180 μg salbutamol). FINDINGS Patients were recruited from January, 2008, to June, 2011. 9986 (96%) of 10,364 patients enrolled in the COPDGene study were included in the analysis population (mean age 59·6 years [SD 9·0]). Paradoxical response was noted in 453 (5%) of 9986 patients and the frequency was similar in patients with COPD (198 [4%] of 4439) and smokers without airflow obstruction (255 [5%] of 5547). Compared with white patients, a paradoxical response was twice as common in African-American patients (227 [7%] of 3282 vs 226 [3%] of 6704; p<0·0001). In the multivariate analyses, African-American ethnic origin (adjusted odds ratio 1·89, 95% CI 1·50-2·39; p<0·0001), less emphysema (0·96, 0·92-0·99; p=0·023), and increased wall-area percentage of the segmental airways (1·04, 1·01-1·08; p=0·023) were independently associated with a paradoxical response. A paradoxical response was independently associated with worse dyspnoea (adjusted β for Modified Medical Research Council Dyspnoea Scale 0·12 [95% CI 0·00 to 0·24]; p=0·05), lower 6 min walk distance (-45·8 [-78·5 to -13·2]; p=0·006), higher Body Mass Index, Airflow Obstruction, Dyspnea, and Exercise Capacity (BODE) index (0·31 [0·19 to 0·43]; p<0·0001), and a greater frequency of severe exacerbations (increased by a factor of 1·35, 1·00-1·81; p=0·048). INTERPRETATION Paradoxical response to β₂ agonists is associated with respiratory morbidity and is more common in African-Americans. These findings might have implications for the use of β2agonists in some patients. FUNDING National Institutes of Health.

Radiological correlates and clinical implications of the paradoxical lung function response to β₂ agonists

BACKGROUND Bronchodilator response has been noted in a significant proportion of patients with chronic obstructive pulmonary disease (COPD). However, there are also reports of a paradoxical response to β₂ agonists resulting in bronchoconstriction. Asymptomatic bronchoconstriction is likely to be far more common than is symptomatic bronchoconstriction with β₂ agonists, but no systematic studies have been done. We assessed the prevalence of paradoxical response in current and former smokers with and without COPD, and its radiological correlates and clinical implications. METHODS Non-Hispanic white and African-American patients (aged 45-80 years) from a large multicentre study COPDGene were classified into two groups on the basis of a paradoxical response, defined as at least a 12% and 200 mL reduction in forced expiratory volume in 1 sec (FEV₁) or forced vital capacity (FVC), or both, after administration of a shortacting β₂ agonist (180 μg salbutamol). FINDINGS Patients were recruited from January, 2008, to June, 2011. 9986 (96%) of 10,364 patients enrolled in the COPDGene study were included in the analysis population (mean age 59·6 years [SD 9·0]). Paradoxical response was noted in 453 (5%) of 9986 patients and the frequency was similar in patients with COPD (198 [4%] of 4439) and smokers without airflow obstruction (255 [5%] of 5547). Compared with white patients, a paradoxical response was twice as common in African-American patients (227 [7%] of 3282 vs 226 [3%] of 6704; p<0·0001). In the multivariate analyses, African-American ethnic origin (adjusted odds ratio 1·89, 95% CI 1·50-2·39; p<0·0001), less emphysema (0·96, 0·92-0·99; p=0·023), and increased wall-area percentage of the segmental airways (1·04, 1·01-1·08; p=0·023) were independently associated with a paradoxical response. A paradoxical response was independently associated with worse dyspnoea (adjusted β for Modified Medical Research Council Dyspnoea Scale 0·12 [95% CI 0·00 to 0·24]; p=0·05), lower 6 min walk distance (-45·8 [-78·5 to -13·2]; p=0·006), higher Body Mass Index, Airflow Obstruction, Dyspnea, and Exercise Capacity (BODE) index (0·31 [0·19 to 0·43]; p<0·0001), and a greater frequency of severe exacerbations (increased by a factor of 1·35, 1·00-1·81; p=0·048). INTERPRETATION Paradoxical response to β₂ agonists is associated with respiratory morbidity and is more common in African-Americans. These findings might have implications for the use of β2agonists in some patients. FUNDING National Institutes of Health.

Smoking duration alone provides stronger risk estimates of chronic obstructive pulmonary disease than pack-years

Background Cigarette smoking is the strongest risk factor for COPD. Smoking burden is frequently measured in pack-years, but the relative contribution of cigarettes smoked per day versus duration towards the development of structural lung disease, airflow obstruction and functional outcomes is not known. Methods We analysed cross-sectional data from a large multicentre cohort (COPDGene) of current and former smokers. Primary outcome was airflow obstruction (FEV1/FVC); secondary outcomes included five additional measures of disease: FEV1, CT emphysema, CT gas trapping, functional capacity (6 min walk distance, 6MWD) and respiratory morbidity (St George’s Respiratory Questionnaire, SGRQ). Generalised linear models were estimated to compare the relative contribution of each smoking variable with the outcomes, after adjustment for age, race, sex, body mass index, CT scanner, centre, age of smoking onset and current smoking status. We also estimated adjusted means of each outcome by categories of pack-years and combined groups of categorised smoking duration and cigarettes/day, and estimated linear trends of adjusted means for each outcome by categorised cigarettes/day, smoking duration and pack-years. Results 10 187 subjects were included. For FEV1/FVC, standardised beta coefficient for smoking duration was greater than for cigarettes/day and pack-years (P<0.001). After categorisation, there was a linear increase in adjusted means FEV1/FVC with increase in pack-years (regression coefficient β=−0.023±SE0.003; P=0.003) and duration over all ranges of smoking cigarettes/day (β=−0.041±0.004; P<0.001) but a relatively flat slope for cigarettes/day across all ranges of smoking duration (β=−0.009±0.0.009; P=0.34). Strength of association of duration was similarly greater than pack-years for emphysema, gas trapping, FEV1, 6MWD and SGRQ. Conclusion Smoking duration alone provides stronger risk estimates of COPD than the composite index of pack-years. Trial registration number Post-results; NCT00608764.

Ventricular geometry from non-contrast non-ECG-gated CT scans: An imaging marker of cardiopulmonary disease in smokers

RATIONALE AND OBJECTIVES Imaging-based assessment of cardiovascular structure and function provides clinically relevant information in smokers. Non-cardiac-gated thoracic computed tomographic (CT) scanning is increasingly leveraged for clinical care and lung cancer screening. We sought to determine if more comprehensive measures of ventricular geometry could be obtained from CT using an atlas-based surface model of the heart. MATERIALS AND METHODS Subcohorts of 24 subjects with cardiac magnetic resonance imaging (MRI) and 262 subjects with echocardiography were identified from COPDGene, a longitudinal observational study of smokers. A surface model of the heart was manually initialized, and then automatically optimized to fit the epicardium for each CT. Estimates of right and left ventricular (RV and LV) volume and free-wall curvature were then calculated and compared to structural and functional metrics obtained from MRI and echocardiograms. RESULTS CT measures of RV dimension and curvature correlated with similar measures obtained using MRI. RV and LV volume obtained from CT inversely correlated with echocardiogram-based estimates of RV systolic pressure using tricuspid regurgitation jet velocity and LV ejection fraction respectively. Patients with evidence of RV or LV dysfunction on echocardiogram had larger RV and LV dimensions on CT. Logistic regression models based on demographics and ventricular measures from CT had an area under the curve of >0.7 for the prediction of elevated right ventricular systolic pressure and ventricular failure. CONCLUSIONS These data suggest that non-cardiac-gated, non-contrast-enhanced thoracic CT scanning may provide insight into cardiac structure and function in smokers.

Arterial and Venous Pulmonary Vascular Morphology and Their Relationship to Findings in Cardiac Magnetic Resonance Imaging in Smokers.

Objective Prior work has described the relationship between pulmonary vascular pruning on computed tomography (CT) scans and metrics of right-sided heart dysfunction in smokers. In this analysis, we sought to look at pruning on a lobar level, as well as examine the effect of the arterial and venous circulation on this association. Methods Automated vessel segmentation applied to noncontrast CT scans from the COPDGene Study in 24 subjects with cardiac magnetic resonance imaging scans was used to create a blood volume distribution profile. These vessels were then manually tracked to their origin and characterized as artery or vein. Results Assessment of pruning on a lobar level revealed associations between pruning and right ventricular function previously not observed on a global level. The right ventricular mass index, the right ventricular end-systolic volume index, and pulmonary arterial-to-aorta ratio were associated with both arterial and venous pruning, whereas right ventricular ejection fraction was associated with only arterial pruning. Conclusions Lobar assessment and segmentation of the parenchymal vasculature into arterial and venous components provide additional information about the relationship between loss of vasculature on CT scans and right ventricular dysfunction.

The use of a standardized order set reduces systemic corticosteroid dose and length of stay for individuals hospitalized with acute exacerbations of COPD: a cohort study

Background Systemic corticosteroids (SC) are an integral part of managing acute exacerbations of COPD (AECOPD). However, the optimal dose and duration vary widely in clinical practice. We hypothesized that the use of a “PowerPlan” order set in the electronic health system (EHS) that includes a 5-day SC order would be associated with a reduced steroid dose and length of stay (LOS) for individuals hospitalized with AECOPD. Patients and methods We conducted a retrospective cohort study of Medicare recipients discharged with an AECOPD diagnosis from our University Hospital from 2014 to 2016. Our EHS-based “COPD PowerPlan” order set included admission, laboratory, pharmacy, and radiology orders for managing AECOPD. The default SC option included intravenous methyl-prednisolone for 24 hours followed by oral prednisone for 4 days. The primary endpoint was the difference in cumulative steroid dose between the PowerPlan and the usual care group. Secondary endpoints included hospital LOS and readmission rates. Results The 250 patients included for analysis were 62±11 years old, 58% male, with an FEV1 55.1%±23.6% predicted. The PowerPlan was used in 72 (29%) patients. Cumulative steroid use was decreased by 31% in the PowerPlan group (420±224 vs 611±462 mg, P<0.001) when compared with usual care. PowerPlan use was independently associated with decreased LOS (3 days; IQR 2–4 days vs 4 days; IQR 3–6 days, P=0.022) without affecting 30- and 90-day readmission rates. Conclusion Use of a standardized EHS-based order set to manage AECOPD was associated with a reduction in steroid dose and hospital LOS.