Selective serotonin reuptake inhibitors and lung function in the multi-ethnic study of atherosclerosis lung study

OBJECTIVE

Depression in patients with Chronic Obstructive Pulmonary Disease (COPD) has been shown to be chronic and potentially increase the burden of symptoms. Selective serotonin reuptake inhibitors (SSRIs) have anti-inflammatory and serotonergic effects that may improve lung function. We hypothesized that participants taking SSRIs have better lung function than those not taking SSRIs. The dataset was the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study. Use of SSRIs was assessed by medication inventory; spirometry was conducted following standard guidelines; dyspnea ratings were self-reported.

RESULTS

Contrary to our hypothesis, FEV1 was lower, and odds of dyspnea were higher among participants taking SSRIs as compared with those not taking an antidepressant; these differences persisted even with control for potential confounders including depressive symptoms. We found no evidence of a beneficial association between SSRI use and lung function or dyspnea in a large US-based cohort.

Symptoms of anxiety and depression and use of anxiolytic-hypnotics and antidepressants in current and former smokers with and without COPD - A cross sectional analysis of the COPDGene cohort

OBJECTIVES

To compare the frequency of anxiety/depressive symptoms and use of anxiolytic-hypnotics/antidepressants in smokers with and without COPD and to identify characteristics associated with having unmedicated symptoms.

METHODS

Cross-sectional analysis of ambulatory, current/former smokers ≥10 pack years enrolled in the COPDGene study. We measured anxiety/depressive symptoms using the Hospital Anxiety and Depression Scale (subscales ≥8), recorded anxiolytic-hypnotic/antidepressant use, and defined unmedicated symptoms as elevated anxiety/depressive symptoms and not on medications. Regression analysis identified characteristics associated with having unmedicated symptoms.

KEY RESULTS

Of 5331 current/former smokers (45% with and 55% without COPD), 1332 (25.0%) had anxiety/depressive symptoms. Anxiety symptoms were similar in frequency in smokers with and without COPD (19.7% overall), while depressive symptoms were most frequent in severe-very severe COPD at 20.7% (13.1% overall). In the entire cohort, 1135 (21.2%) were on medications. Anxiolytic-hypnotic use was highest in severe-very severe COPD (range 7.6%-12.0%), while antidepressant use showed no significant variation in smokers with and without COPD (range 14.7%-17.1%). Overall, 881 (66% of those with symptoms) had unmedicated symptoms, which was associated with African American race (adjusted OR 2.95, 95% CI 2.25-3.87), male gender (adjusted OR 1.93, 95% CI 1.57-2.36), no health insurance (adjusted OR 2.38, 95% CI 1.30-4.35), severe-very severe COPD (adjusted OR 1.48, 95% CI 1.04-2.11), and higher respiratory symptoms/exacerbation history (adjusted OR 2.21, 95% CI 1.62-3.02).

CONCLUSIONS

Significant unmet mental health care needs exist in current and former smokers with and without COPD. One in five have unmedicated symptoms, identified by key demographic and clinical characteristics.

PRIMARY FUNDING SOURCE

National Institutes of Health and The COPD Foundation.

The Impact of Hypomania on Aerobic Capacity and Cardiopulmonary Functioning-A Case Report

Background: Hypomanic episodes are characterized by increased goal-directed behavior and psychomotor agitation. While the affective, cognitive, and behavioral manifestations of such episodes are well-documented, their physiological influence on aerobic capacity and cardiopulmonary functioning are unknown. Methods: We describe a case report of an individual with schizophrenia who experienced a hypomanic episode while serving as a control participant (wait list) in a single-blind, randomized clinical trial examining the impact of aerobic exercise (AE) on neurocognition in people schizophrenia. As part of the trial, participants completed two scheduled clinical assessments and cardiopulmonary exercise tests (VO₂max) at baseline and 12 weeks later at end of study. All participants received standard psychiatric care during the trial. Following a baseline assessment in which he displayed no evidence of mood lability, the subject returned on Week-12 for his scheduled follow-up assessment displaying symptoms of hypomania. He was able to complete the follow-up assessment, as well as third assessment 2 weeks later (Week-14) when his hypomanic symptoms ebbed. Results: While not engaging in AE, the subject's aerobic capacity, as indexed by VO₂max, increased by 33% from baseline to Week-12. In comparison, participants engaged in the aerobic exercise training increased their aerobic capacity on average by 18%. In contrast, participants in the control group displayed a small decline (-0.5%) in their VO₂max scores. Moreover, the subject's aerobic capacity increased even further by Week-14 (49% increase from baseline), despite the ebbing of his hypomania symptoms at that time. These changes were accompanied by increases in markers of aerobic fitness including peak heart rate, respiratory exchange rate, peak minute ventilation, watts, and peak systolic blood pressure. Resting systolic and diastolic blood pressure, and peak diastolic blood pressure remained unchanged. Conclusions: Our findings suggest that hypomania produce substantial increase in aerobic capacity and that such elevations may remain sustained following the ebbing of hypomanic symptoms. Such elevations may be attributed to increased mobility and goal-directed behavior associated with hypomania, as individuals in hypomanic states may ambulate more frequently, for longer duration, and/or at higher intensity. Our results provide a first and unique view into the impact of hypomania on aerobic capacity and cardiopulmonary functioning.

Serum Matrix Metalloproteinase-7, Respiratory Symptoms, and Mortality in Community-Dwelling Adults. MESA (Multi-Ethnic Study of Atherosclerosis)

RATIONALE

Matrix metalloproteinase-7 (MMP-7) has been implicated in interstitial lung disease pathobiology and proposed as a diagnostic and prognostic biomarker of idiopathic pulmonary fibrosis.

OBJECTIVES

To test associations between serum MMP-7 and lung function, respiratory symptoms, interstitial lung abnormalities (ILA), and all-cause mortality in community-dwelling adults sampled without regard to respiratory symptoms or disease.

METHODS

We measured serum MMP-7 in 1,227 participants in MESA (Multi-Ethnic Study of Atherosclerosis) at baseline. The 5-year outcome data were available for spirometry (n = 697), cough (n = 722), and dyspnea (n = 1,050). The 10-year outcome data were available for ILA (n = 561) and mortality (n = 1,227). We used linear, logistic, and Cox regression to control for potential confounders.

MEASUREMENTS AND MAIN RESULTS

The mean (±SD) serum MMP-7 level was 4.3 (±2.5) ng/ml (range, 1.2-24.1 ng/ml). In adjusted models, each natural log unit increment in serum MMP-7 was associated with a 3.7% absolute decrement in FVC% (95% confidence interval [CI] = 0.9-6.6%), a 1.6-fold increased odds of exertional dyspnea (95% CI = 1.3-1.9), a 1.5-fold increased odds of ILAs (95% CI = 1.1-2.1), and a 2.2-fold increased all-cause mortality rate (95% CI = 1.9-2.5). The associations with ILA and mortality tended to be stronger among never-smokers (P values for interaction 0.06 and 0.01, respectively).

CONCLUSIONS

Serum MMP-7 levels may be a quantitative biomarker of subclinical extracellular matrix remodeling in the lungs of community-dwelling adults, which may facilitate investigation of subclinical interstitial lung disease.

Frailty and maximal exercise capacity in adult lung transplant candidates

BACKGROUND

Frail lung transplant candidates are more likely to be delisted or die without receiving a transplant. Further knowledge of what frailty represents in this population will assist in developing interventions to prevent frailty from developing. We set out to determine whether frail lung transplant candidates have reduced exercise capacity independent of disease severity and diagnosis.

METHODS

Sixty-eight adult lung transplant candidates underwent cardiopulmonary exercise testing (CPET) and a frailty assessment (Fried's Frailty Phenotype (FFP)). Primary outcomes were peak workload and peak aerobic capacity (V˙O₂). We used linear regression to adjust for age, gender, diagnosis, and lung allocation score (LAS).

RESULTS

The mean ± SD age was 57 ± 11 years, 51% were women, 57% had interstitial lung disease, 32% had chronic obstructive pulmonary disease, 11% had cystic fibrosis, and the mean LAS was 40.2 (range 19.2-94.5). In adjusted models, peak workload decreased by 10 W (95% CI 4.7 to 14.6) and peak V˙O₂ decreased by 1.8 mL/kg/min (95% CI 0.6 to 2.9) per 1 unit increment in FFP score. After adjustment, exercise tolerance was 38 W lower (95% CI 18.4 to 58.1) and peak V˙O₂ was 8.5 mL/kg/min lower (95% CI 3.3 to 13.7) among frail participants compared to non-frail participants. Frailty accounted for 16% of the variance (R²) of watts and 19% of the variance of V˙O₂ in adjusted models.

CONCLUSION

Frailty contributes to reduced exercise capacity among lung transplant candidates independent of disease severity.

Cardiopulmonary exercise factors predict survival in patients with advanced interstitial lung disease referred for lung transplantation

BACKGROUND

The purpose of this work was to determine if parameters assessed during Cardiopulmonary Exercise Testing (CPET) while using supplemental oxygen can independently predict one-year transplant-free survival in patients with Interstitial Lung Disease (ILD) referred for lung transplant evaluation.

METHODS

We performed a chart review of patients with ILD who completed CPET with 30% FiO₂ and gathered spirometry, pulmonary hemodynamic, six-minute walk, and CPET data. The primary end-point was death or lung transplantation within one-year of CPET.

RESULTS

The final data set included 192 patients. 79 patients died/underwent transplant, 113 survived transplant-free. Multivariable Cox regression revealed peak workload % predicted, nadir CPET SpO₂, and FVC% predicted as independent predictors of one-year transplant-free survival. Of the independent predictors of survival, receiver operating characteristics analysis revealed peak workload %predicted cutoff of 35% to be highly discriminatory, more so than nadir CPET SpO₂ or FVC % predicted in identifying patients at risk for one-year mortality or transplant (peak workload % predicted < 35% HR = 4.71, 95% CI = 2.64-8.38 and area under the curve (AUC) = 0.740, nadir CPET SpO₂ < 86% HR = 2.27, 95%CI = 1.41-3.68, AUC = 0.645, FVC %predicted <45% HR = 1.82, 95% CI = 1.15-2.87, AUC = 0.624).

CONCLUSION

Peak workload % predicted, nadir CPET SpO₂, and FVC% predicted in ILD patients referred for lung transplant evaluation are independently predictive of one-year mortality or need for transplant.

Lung function, percent emphysema, and QT duration: The Multi-Ethnic Study of Atherosclerosis (MESA) lung study

BACKGROUND

The QT interval on electrocardiogram (ECG) reflects ventricular repolarization; a prolonged QT interval is associated with increased mortality risk. Prior studies suggest an association between chronic obstructive pulmonary disease (COPD) and prolonged QT interval. However, these studies were small and often enrolled hospital-based samples. We tested the hypotheses that lower lung function and increased percent emphysema on computed tomography (CT) are associated with a prolonged QT interval in a general population sample and additionally in those with COPD.

METHODS

As part of the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study, we assessed spirometry, full-lung CT scans, and ECGs in participants aged 45-84 years. The QT on ECGs was corrected for heart rate (QTc) using the Framingham formula. QTc values = 460 msec in women and ≥450 msec in men were considered abnormal (prolonged QT_C). Multivariate regression models were used to examine the cross-sectional association between pulmonary measures and QT_C. RESULTS: The mean age of the sample of 2585 participants was 69 years, and 47% were men. There was an inverse association between FEV₁%, FVC%, FEV₁/FVC%, emphysema, QTc duration and prolonged QTc. Gender was a significant interaction term, even among never smokers. Having severe COPD was also associated with QTc prolongation.

CONCLUSIONS

Our analysis revealed a significant association between lower lung function and longer QTc in men but not in women in a population-based sample. Our findings suggest the possibility of gender differences in the risk of QTc-associated arrhythmias in a population-based sample.

Primary graft dysfunction: Long-term physical function outcomes among lung transplant recipients

BACKGROUND

Adults with primary graft dysfunction (PGD) after lung transplantation are at increased risk for pulmonary and functional impairment. No prior studies have described the long-term (within 1.5 years of transplant) cardiopulmonary exercise testing (CPET) results in adults with grade 3 PGD. The objective of this study was to compare the functional outcomes of lung transplant patients with and without grade 3 PGD via CPET and six-minute talk tests (6MWD).

METHODS

243 adults underwent lung transplantation between 2003 and 2010, 128 (53%) of whom underwent CPET and 6MWD within 12-18 months of transplantation. The primary measure of exposure was grade 3 PGD at 72 h, however grade 3 PGD within 72 h was also assessed. In addition, the impact of potential confounding variables was explored.

RESULTS

Approximately one-third (32%) of the 243 patients experienced grade 3 PGD within 72 h; among these, 15 (6%) had grade 3 PGD at the 72 h time point. There were no differences in CPET or 6MWD between those with and without grade 3 PGD at 72 h despite a longer length of hospital stay and lower pulmonary function. Similar results were seen for patients with and without grade 3 PGD within 72 h, with the exception of a lower heart rate on CPET.

CONCLUSIONS

Participants with grade 3 PGD are able to achieve functional outcomes comparable to those without PGD.

High attenuation areas on chest computed tomography in community-dwelling adults: the MESA study

Evidence suggests that lung injury, inflammation and extracellular matrix remodelling precede lung fibrosis in interstitial lung disease (ILD). We examined whether a quantitative measure of increased lung attenuation on computed tomography (CT) detects lung injury, inflammation and extracellular matrix remodelling in community-dwelling adults sampled without regard to respiratory symptoms or smoking.We measured high attenuation areas (HAA; percentage of lung voxels between -600 and -250 Hounsfield Units) on cardiac CT scans of adults enrolled in the Multi-Ethnic Study of Atherosclerosis.HAA was associated with higher serum matrix metalloproteinase-7 (mean adjusted difference 6.3% per HAA doubling, 95% CI 1.3-11.5), higher interleukin-6 (mean adjusted difference 8.8%, 95% CI 4.8-13.0), lower forced vital capacity (FVC) (mean adjusted difference -82 mL, 95% CI -119--44), lower 6-min walk distance (mean adjusted difference -40 m, 95% CI -1--80), higher odds of interstitial lung abnormalities at 9.5 years (adjusted OR 1.95, 95% CI 1.43-2.65), and higher all cause-mortality rate over 12.2 years (HR 1.58, 95% CI 1.39-1.79).High attenuation areas are associated with biomarkers of inflammation and extracellular matrix remodelling, reduced lung function, interstitial lung abnormalities, and a higher risk of death among community-dwelling adults.

Analysis of Skeletal Muscle Torque Capacity and Circulating Ceramides in Patients with Advanced Heart Failure

BACKGROUND

Heart failure (HF)-related exercise intolerance is thought to be perpetuated by peripheral skeletal muscle functional, structural, and metabolic abnormalities. We analyzed specific dynamics of muscle contraction in patients with HF compared with healthy, sedentary controls.

METHODS

Isometric and isokinetic muscle parameters were measured in the dominant upper and lower limbs of 45 HF patients and 15 healthy age-matched controls. Measurements included peak torque normalized to body weight, work normalized to body weight, power, time to peak torque, and acceleration and deceleration to maximum strength times. Body morphometry (dual energy X-ray absorptiometry scan) and circulating fatty acids and ceramides (lipodomics) were analyzed in a subset of subjects (18 HF and 9 controls).

RESULTS

Extension and flexion time-to-peak torque was longer in the lower limbs of HF patients. Furthermore, acceleration and deceleration times in the lower limbs were also prolonged in HF subjects. HF subjects had increased adiposity and decreased lean muscle mass compared with controls. Decreased circulating unsaturated fatty acids and increased ceramides were found in subjects with HF.

CONCLUSIONS

Delayed torque development suggests skeletal muscle impairments that may reflect abnormal neuromuscular functional coupling. These impairments may be further compounded by increased adiposity and inflammation associated with increased ceramides.

Use of Active-Play Video Games to Enhance Aerobic Fitness in Schizophrenia: Feasibility, Safety, and Adherence

OBJECTIVE

Active-play video games have been used to enhance aerobic fitness in various clinical populations, but their use among individuals with schizophrenia has been limited.

METHODS

Feasibility, acceptability, safety, and adherence data were obtained for use of aerobic exercise (AE) equipment by 16 individuals with schizophrenia during a 12-week AE program consisting of three one-hour exercise sessions per week. Equipment included exercise video games for Xbox 360 with Kinect motion sensing devices and traditional exercise equipment.

RESULTS

Most participants (81%) completed the training, attending an average of 79% of sessions. The proportion of time spent playing Xbox (39%) exceeded time spent on any other type of equipment. When using Xbox, participants played 2.24±1.59 games per session and reported high acceptability and enjoyment ratings, with no adverse events.

CONCLUSIONS

Measures of feasibility, acceptability, adherence, and safety support the integration of active-play video games into AE training for people with schizophrenia.

Left and Right Ventricular Functional Dynamics Determined by Echocardiograms Before and After Lung Transplantation

Impaired cardiac function is considered a contraindication for lung transplantation (LT). Because right ventricular (RV) function is expected to improve after LT, poor left ventricular (LV) function is often the determinant for LT eligibility. However, the changes in cardiac function before and after LT have not yet been elucidated. Therefore, we reviewed echocardiograms obtained from 67 recipients before and after LT. In a subset of 49 patients, both RV and LV longitudinal strains based on 2-dimensional speckle tracking echocardiography were analyzed. The cardiopulmonary exercise tests were also reviewed. All patients showed significant improvements in their exercise capacity after LT. RV echo parameters improved in all patients after LT (RV fractional area change: 36.7 ± 5.6% to 41.5 ± 2.7%, RV strain: -15.5 ± 2.9% to -18.0 ± 2.1%, RV E/E': 8.4 ± 1.8 to 7.7 ± 1.8; all p <0.05). Overall, the left ventricular ejection fraction (LVEF) did not change (58.7 ± 6.0% to 57.5 ± 9.7%, p = 0.385); however, 20 patients (30%) showed >10% decrease in LVEF after LT (61.5 ± 6.1% to 47.3 ± 4.2%, p <0.001) and an increase in LV E/E' (11.8 ± 1.8 to 12.9 ± 2.2, p = 0.049). Multivariate logistic regression analysis revealed that pre-LT LV E/E' was associated with decrease in LVEF after LT (odds ratio 1.381, 95% confidence interval 1.010 to 1.947, p = 0.043). Furthermore, patients with strain data showed that lower pre-LT LV strain was independently associated with LVEF decrease after LT (odds ratio 1.293, 95% confidence interval 1.088 to 1.614, p = 0.002). Although RV function improves after LT, LV systolic and diastolic functions deteriorate in a sizable proportion of patients. Impaired LV diastolic function before transplant appears to increase the risk of LVEF deterioration after LT.

Supplementation of l-Alanyl-l-Glutamine and Fish Oil Improves Body Composition and Quality of Life in Patients With Chronic Heart Failure

BACKGROUND

Skeletal muscle dysfunction and exercise intolerance are clinical hallmarks of patients with heart failure. These have been linked to a progressive catabolic state, skeletal muscle inflammation, and impaired oxidative metabolism. Previous studies suggest beneficial effects of ω-3 polyunsaturated fatty acids and glutamine on exercise performance and muscle protein balance.

METHODS AND RESULTS

In a randomized double-blind, placebo-controlled trial, 31 patients with heart failure were randomized to either l-alanyl-l-glutamine (8 g/d) and polyunsaturated fatty acid (6.5 g/d) or placebo (safflower oil and milk powder) for 3 months. Cardiopulmonary exercise testing, dual-energy x-ray absorptiometry, 6-minute walk test, hand grip strength, functional muscle testing, echocardiography, and quality of life and lateral quadriceps muscle biopsy were performed at baseline and at follow-up. Oxidative capacity and metabolic gene expression were analyzed on muscle biopsies. No differences in muscle function, echocardiography, 6-minute walk test, or hand grip strength and a nonsignificant increase in peak VO2 in the treatment group were found. Lean body mass increased and quality of life improved in the active treatment group. Molecular analysis revealed no differences in muscle fiber composition, fiber cross-sectional area, gene expression of metabolic marker genes (PGC1α, CPT1, PDK4, and GLUT4), and skeletal muscle oxidative capacity.

CONCLUSIONS

The combined supplementation of l-alanyl-l-glutamine and polyunsaturated fatty acid did not improve exercise performance or muscle function but increased lean body mass and quality of life in patients with chronic stable heart failure. These findings suggest potentially beneficial effects of high-dose nutritional polyunsaturated fatty acids and amino acid supplementations in patients with chronic stable heart failure.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01534663.

The Impact of Aerobic Exercise on Brain-Derived Neurotrophic Factor and Neurocognition in Individuals With Schizophrenia: A Single-Blind, Randomized Clinical Trial

Individuals with schizophrenia display substantial neurocognitive deficits for which available treatments offer only limited benefits. Yet, findings from studies of animals, clinical and nonclinical populations have linked neurocognitive improvements to increases in aerobic fitness (AF) via aerobic exercise training (AE). Such improvements have been attributed to up-regulation of brain-derived neurotrophic factor (BDNF). However, the impact of AE on neurocognition, and the putative role of BDNF, have not been investigated in schizophrenia. Employing a proof-of-concept, single-blind, randomized clinical trial design, 33 individuals with schizophrenia were randomized to receive standard psychiatric treatment (n = 17; "treatment as usual"; TAU) or attend a 12-week AE program (n = 16) utilizing active-play video games (Xbox 360 Kinect) and traditional AE equipment. Participants completed assessments of AF (indexed by VO2 peak ml/kg/min), neurocognition (MATRICS Consensus Cognitive Battery), and serum-BDNF before and after and 12-week period. Twenty-six participants (79%) completed the study. At follow-up, the AE participants improved their AF by 18.0% vs a -0.5% decline in the TAU group (P = .002) and improved their neurocognition by 15.1% vs -2.0% decline in the TAU group (P = .031). Hierarchical multiple regression analyses indicated that enhancement in AF and increases in BDNF predicted 25.4% and 14.6% of the neurocognitive improvement variance, respectively. The results indicate AE is effective in enhancing neurocognitive functioning in people with schizophrenia and provide preliminary support for the impact of AE-related BDNF up-regulation on neurocognition in this population. Poor AF represents a modifiable risk factor for neurocognitive dysfunction in schizophrenia for which AE training offer a safe, nonstigmatizing, and side-effect-free intervention.

Effect of lung transplantation on heart rate response to exercise

OBJECTIVES

To evaluate if patients have a change in percent of predicted heart rate reserve used at peak exercise (%HRR) after lung transplantation, even at matching workloads.

BACKGROUND

Lung disease of obstructive, restrictive, and mixed types may be associated with an autonomic imbalance. Lung transplantation may improve the effects of pulmonary disease on cardiac function. However, the effect of lung transplantation on heart rate responses during exercise has not been investigated in detail.

METHODS

Retrospective review of patients who underwent lung transplantation. Pre and post transplant cardiopulmonary exercise tests were reviewed.

RESULTS

The %HRR significantly improved by a median of 37% (p < 0.001) following lung transplantation. When matching workloads were analyzed, the %HRR also decreased from a median of 36% to 24% (p < 0.001).

CONCLUSIONS

Corresponding to an increase in peak exercise capacity, percentage of heart rate reserve used improves significantly after lung transplantation, even at matching workloads, indicating a likely improvement in autonomic modulation.

Quantification of Improvements in Static and Dynamic Ventilatory Measures Following Lung Volume Reduction Surgery for Severe COPD

Rationale: This study quantitatively measured the effects of lung volume reduction surgery (LVRS) on spirometry, static and dynamic lung and chest wall volume subdivision mechanics, and cardiopulmonary exercise measures. Methods: Patients with severe COPD (mean FEV₁ = 23 ± 6% predicted) undergoing LVRS evaluation were recruited. Spirometry, plethysmography and exercise capacity were obtained within 6 months pre-LVRS and again within 12 months post- LVRS. Ventilatory mechanics were quantified using stationary optoelectronic plethysmography (OEP) during spontaneous tidal breathing and during maximum voluntary ventilation (MVV). Statistical significance was set at P< 0.05. Results:Ten consecutive patients met criteria for LVRS (5 females, 5 males, age: 62±6yrs). Post -LVRS (mean follow up 7 months ± 2 months), the group showed significant improvements in dyspnea scores (pre 4±1 versus post 2 ± 2), peak exercise workload (pre 37± 21 watts versus post 50 ± 27watts ), heart rate (pre 109±19 beats per minutes [bpm] versus post 118±19 bpm), duty cycle (pre 30.8 ± 3.8% versus post 38.0 ± 5.7%), and spirometric measurements (forced expiratory volume in 1 second [FEV₁] pre 23 ± 6% versus post 32 ± 13%, total lung capacity / residual lung volume pre 50 ± 8 versus 50 ± 11) . Six to 12 month changes in OEP measurements were observed in an increased percent contribution of the abdomen compartment during tidal breathing (41.2±6.2% versus 44.3±8.9%, P=0.03) and in percent contribution of the pulmonary ribcage compartment during MVV (34.5±10.3 versus 44.9±11.1%, P=0.02). Significant improvements in dynamic hyperinflation during MVV occurred, demonstrated by decreases rather than increases in end expiratory volume (EEV) in the pulmonary ribcage (pre 207.0 ± 288.2 ml versus post -85.0 ± 255.9 ml) and abdominal ribcage compartments (pre 229.1 ± 182.4 ml versus post -17.0 ± 136.2 ml) during the maneuver. Conclusions: Post-LVRS, patients with severe COPD demonstrate significant favorable changes in ventilatory mechanics, during tidal and maximal voluntary breathing. Future work is necessary to determine if these findings are clinically relevant, and extend to other environments such as exercise.

Aerobic fitness and body mass index in individuals with schizophrenia: Implications for neurocognition and daily functioning

Previous reports indicate that among healthy individuals low aerobic fitness (AF) and high body-mass index (BMI) predict poor neurocognition and daily-functioning. It is unknown whether these associations extend to disorders characterized by poor neurocognition, such as schizophrenia. Therefore, we compared AF and BMI in individuals with schizophrenia and non-clinical controls, and then within the schizophrenia group we examined the links between AF, BMI, neurocognition and daily-functioning. Thirty-two individuals with schizophrenia and 64 gender- and age-matched controls completed assessments of AF (indexed by VO2max) and BMI. The former also completed measures of neurocognition, daily-functioning and physical activity. The schizophrenia group displayed significantly lower AF and higher BMI. In the schizophrenia group, AF was significantly correlated with overall neurocognition (r=0.57), along with executive functioning, working memory, social cognition, and processing speed. A hierarchical regression analysis indicated that AF accounted for 22% of the neurocognition variance. Furthermore, AF was significantly correlated with overall daily-functioning (r=0.46). In contrast, BMI displayed significant inverse correlations with neurocognition, but no associations to daily-functioning. AF was significantly correlated physical activity. The authors discuss the potential use of AF-enhancing interventions to improve neurocognitive and daily-functioning in schizophrenia, along with putative neurobiological mechanisms underlying these links, including Brain-Derived Neurotrophic Factor.

Ventilatory efficiency before and after lung volume reduction surgery

BACKGROUND

Lung volume reduction surgery (LVRS) has been shown to improve the clearance of carbon dioxide and minute ventilation (V̇E) in select patients with COPD. One variable often assessed in COPD is ventilatory efficiency (V̇E/V̇CO2 ).

METHODS

We compared 55 LVRS subjects with 25 controls from the National Emphysema Treatment Trial. V̇E/V̇CO2 was calculated from cardiopulmonary exercise testing at baseline and 6-months. We sought to assess V̇E/V̇CO2 changes with LVRS compared with controls who only received standard medical care.

RESULTS

At 6 months, the LVRS group significantly increased peak V̇O2 , work load, V̇E, V̇CO2 , and tidal volume while lowering peak and lowest V̇E/V̇CO2 (improved ventilatory efficiency) and end-tidal carbon dioxide pressure. The control group did not display these changes. The changes were greatest in the LVRS subjects who improved their exercise capacity after surgery (> 10 W).

CONCLUSIONS

The changes were greatest in the LVRS subjects who showed the most functional improvement, indicating an association of improved ventilation with improved functional outcome.

Impact of pulmonary hypertension on exercise performance in patients with interstitial lung disease undergoing evaluation for lung transplantation

BACKGROUND AND OBJECTIVE

Pulmonary hypertension (PH) is a known complication in patients with interstitial lung disease (ILD). Cardiopulmonary exercise testing (CPET) is an essential tool for the assessment of patients with cardiac and pulmonary diseases due to its prognostic and therapeutic implications. Few studies have evaluated the relationship between CPET response and mean pulmonary artery pressures (mPAP) in ILD. The purpose of the present study was to determine and compare the potential correlations between CPET, 6-min walk test (6MWT), pulmonary function testing (PFT) and PH in patients with ILD being evaluated for lung transplantation.

METHODS

The present study reviewed patients with ILD who received lung transplantations and had CPETs within 2 years before transplantation, right heart catheterizations, PFTs and 6MWTs within 4 months of CPET.

RESULTS

A total of 72 patients with ILD were analysed; 36% had PH. There were significant correlations between mPAP and CPET parameters in patients with PH; but mPAP had no impact on percent of predicted diffusion capacity of the lung for carbon monoxide or 6-min walk distance (6MWD). CPET parameters were able to detect differences between levels of severity of PH through the use of the ratio of minute ventilation to rate of carbon dioxide production (VE/VCO2) and the partial pressure of end-tidal carbon dioxide.

CONCLUSIONS

This is the first study that analyses 6MWD, PFT and CPET in patients with ILD awaiting lung transplantation with and without PH. The present study demonstrates the significant impact of PH on exercise capacity and performance in patients with ILD awaiting lung transplantation.

Comparison of cardiopulmonary exercise testing variables in COPD patients with and without coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a common concomitant condition and an important cause of morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD). Since COPD and CAD can both independently cause reduced exercise capacity, it is reasonable to hypothesize that the combination of these diseases may compound the abnormalities observed during cardiopulmonary exercise testing (CPET). However, little is known about the impact of CAD on the CPET response in COPD patients. The aim of this study is to compare exercise capacity and gas exchange variables in COPD patients with and without CAD.

METHODS

Fifty-four COPD subjects without CAD (COPDnoCAD) were matched to 54 COPD subjects diagnosed with CAD (COPD/CAD) according to age, gender, body mass index and severity of COPD. All subjects underwent resting pulmonary function and symptom-limited CPET.

RESULTS

Comparing COPDnoCAD patients with COPD/CAD patients revealed that exercise capacity, as measured by % peak oxygen consumption (42 ± 16% vs 53 ± 19%, p = 0.002) and % peak wattage (23 ± 13% vs 32 ± 16%, p = 0.001), was significantly lower in COPD/CAD. Ventilatory response, as measured by VE/VCO2 nadir (36 ± 9 vs 32 ± 5, p = 0.001), was significantly higher in COPD/CAD, with % peak VO2 and VE/VCO2 nadir correlating to % FEV1 and inversely correlating with %DLCO.

CONCLUSION

COPD patients with CAD have significantly impaired CPET responses with lower exercise capacity and impaired gas exchange compared to COPD patients without CAD. These findings may affect the clinical interpretation of CPET data in COPD patients who have concomitant CAD.

Chronotropic incompetence predicts mortality in severe obstructive pulmonary disease

We evaluated the prevalence of chronotropic incompetence (CI), a marker of autonomic dysfunction, and its prognostic value in patients with chronic obstructive pulmonary disease (COPD). We performed a retrospective analysis of 449 patients with severe COPD who underwent a cardiopulmonary exercise test, after excluding patients with lung volume reduction surgery, left ventricular dysfunction and those not in sinus rhythm. CI was defined as percent predicted heart rate reserve (%HRR). Events were defined as death or lung transplant during a median follow-up of 68 months. Median age was 61 years; median percent predicted forced expiratory volume in one second (%FEV1) of 25% and median %HRR of 33%. The hazard ratio for an event in the lowest quartile of %HRR, taking the highest quartile as reference, was of 3.2 (95% confidence interval: 2.1-4.8; p<0.001). In a multivariate regression model, %HRR was an independent predictor of events. In conclusion, CI was an independent and powerful outcome predictor in patients with severe COPD.

Optoelectronic plethysmography compared to spirometry during maximal exercise

The purpose of this study was to compare simultaneous measurements of tidal volume (Vt) by optoelectronic plethysmography (OEP) and spirometry during a maximal cycling exercise test to quantify possible differences between methods. Vt measured simultaneously by OEP and spirometry was collected during a maximal exercise test in thirty healthy participants. The two methods were compared by linear regression and Bland-Altman analysis at submaximal and maximal exercise. The average difference between the two methods and the mean percentage discrepancy were calculated. Submaximal exercise (SM) and maximal exercise (M) Vt measured by OEP and spirometry had very good correlation, SM R=0.963 (p<0.001), M R=0.982 (p<0.001) and high degree of common variance, SM R(2)=0.928, M R(2)=0.983. Bland-Altman analysis demonstrated that during SM, OEP could measure exercise Vt as much as 0.134 L above and -0.025 L below that of spirometry. OEP could measure exercise Vt as much as 0.188 L above and -0.017 L below that of spirometry. The discrepancy between measurements was -2.0 ± 7.2% at SM and -2.4 ± 3.9% at M. In conclusion, Vt measurements at during exercise by OEP and spirometry are closely correlated and the difference between measurements was insignificant.

The effect of lung volume reduction surgery on chronotropic incompetence

BACKGROUND

Chronotropic incompetence (CI) is a marker of poor prognosis in patients with COPD. Treatments that improve pulmonary function and exercise capacity may affect CI. Objectives are to evaluate CI before and after lung volume reduction surgery (LVRS) and determine if changes in CI are associated with changes in pulmonary function and exercise capacity.

METHODS

We performed a retrospective review of 75 patients who underwent LVRS and who had complete cardiopulmonary exercise testing and concurrent pulmonary function tests two months before and about 6 months after surgery. Additionally we evaluated 28 control patients that were randomized to medical treatment as part of the National Emphysema Treatment Trial at our center. We studied CI using the percent of predicted heart rate reserve=(heart rate peak-heart rate rest)/((208-0.7×age)-heart rate rest)×100, before and after surgery and compared it to the control group.

RESULTS

Mean percent of predicted heart rate reserve improved from 41% to 50% (p-value <0.001) after LVRS, while the control group did not change. The mean forced vital capacity and expiratory volume in 1s, peak oxygen consumption, carbon dioxide production, ventilation, tidal volume and maximal workload all improved in the surgery group, while the controls did not improve.

CONCLUSIONS

CI improves after LVRS in a population of patients with COPD. CI improvements are associated with the increases in pulmonary function and exercise capacity. This improvement is seen in a domain of known cardiopulmonary impairment prior to surgery that improves as a positive response to the therapy of LVRS.

Exercise testing parameters associated with post lung transplant mortality

Exercise performance during cardiopulmonary exercise testing (CPET) is a predictor of all-cause mortality in the general population and in patients with coronary heart disease. Mortality beyond one-year after lung transplantation (LTx) is due to multiple causes, is difficult to predict, and has not been fully evaluated in LTx recipients. We hypothesized that, similar to other populations, exercise performance after LTx may be associated with mortality. A retrospective review of all LTx recipients who underwent CPET between 2001 and 2009 was conducted. Chosen endpoint was re-transplantation or death. Survival analysis was performed using Cox proportional-hazard models in 183 patients. After adjusting for bronchiolitis obliterans syndrome (BOS) score, for every 10% increment in percent-predicted peak watts or percent-predicted peak oxygen uptake patients were approximately 23% less likely to experience an endpoint. We conclude that after adjusting for BOS score, lower exercise capacity one-year post LTx is independently associated with mortality. This may imply a protective role of exercise capacity in the LTx population.

Exercise ventilatory kinematics in endurance trained and untrained men and women

To determine how increased ventilatory demand impacts ventilatory kinematics, we compared the total chest wall volume variations (V(CW)) of male and female endurance-trained athletes (ET) to untrained individuals (UT) during exercise. We hypothesized that training and gender would have an effect on V(CW) and kinematics at maximal exercise. Gender and training significantly influenced chest wall kinematics. Female ET did not change chest wall end-expiratory volume (V(CW,ee)) or pulmonary ribcage (V(RCp,ee)) with exercise, while female UT significantly decreased V(CW,ee) and V(RCp,ee) with exercise (p<0.05). Female ET significantly increased pulmonary ribcage end-inspiratory volume (V(RCp,ei)) with exercise (p<0.05), while female UT did not change V(RCp,ei) with exercise. Male ET significantly increased V(RCp,ei) with exercise (p<0.05); male UT did not. Men and women had significantly different variation of V(CW) (p<0.05). Women demonstrated the greatest variation of V(CW) in the pulmonary ribcage compartment (V(RCp)). Men had even volumes variation of the V(RCp) and the abdomen (V(Ab)). In conclusion, gender and training had a significant impact on ventilatory kinematics.