Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema

New Therapies in Outpatient Pulmonary Medicine

Newer medications and devices, as well as greater understanding of the benefits and limitations of existing treatments, have led to expanded treatment options for patients with lung disease. Treatment advances have led to improved outcomes for patients with asthma, chronic obstructive pulmonary disease, interstitial lung disease, pulmonary hypertension, and cystic fibrosis. The risks and benefits of available treatments are substantially variable within these heterogeneous disease groups. Defining the role of newer therapies mandates both an understanding of these disorders and overall treatment approaches. This section will review general treatment approaches in addition to focusing on newer therapies for these conditions..

Surgical and bronchoscopic pulmonary function-improving procedures in lung emphysema

COPD is a highly prevalent, chronic and irreversible obstructive airway disease without curative treatment. Standard therapeutic strategies, both non-pharmacological and pharmacological, have only limited effects on lung function parameters of patients with severe disease. Despite optimal pharmacological treatment, many patients with severe COPD still have a high burden of dyspnoea and a poor quality of life. If these patients have severe lung emphysema, with hyperinflation as the driver of symptoms and exercise intolerance, lung volume reduction may be an effective treatment with a significant impact on lung function, exercise capacity and quality of life. Currently, different lung volume reduction approaches, both surgical and bronchoscopic, have shown encouraging results and have been implemented in COPD treatment recommendations. Nevertheless, choosing the optimal lung volume reduction strategy for an individual patient remains challenging. Moreover, there is still room for improving durability of effect and safety in all available procedures. Ongoing and innovative research is essential to push this field forwards. This review provides an overview of results and limitations of the current lung volume reduction options for patients with severe lung emphysema and hyperinflation.

By deflating the lungs pulmonologists help the cardiologists. A literature review

In this review, we present the effects of lung hyperinflation on the cardiovascular system (CVS) and the beneficial outcomes of different deflation treatment modalities. We discuss the effects of long-acting bronchodilator drugs, medical and surgical lung volume reduction on the performance of the CVS. Although there is a small number of studies investigating lung deflation and the CVS, the short-term improvement in heart function was clearly demonstrated. However, more studies, with longer duration, are needed to verify these significant beneficial effects of deflation of the lungs on the CVS. Dynamic hyperinflation during exercise could be a research model to investigate further the effects of lung hyperinflation and/or deflation on the CVS.

Lung Volume Reduction Surgery Reduces Pulmonary Arterial Hypertension Associated With Severe Lung Emphysema and Hypercapnia

Lung volume reduction surgery (LVRS) represents a standard surgical approach for patients with severe pulmonary emphysema. One of the relevant risk factors for LVRS is the presence of pulmonary arterial hypertension (PAH). The aim of this study is to assess the postoperative changes in pulmonary arterial pressure (PAP) after LVRS for patients with severe pulmonary emphysema compared with preoperative measures. N = 61 consecutive patients with severe pulmonary emphysema and preoperative evidence for PAH (pulmonary arterial systolic pressure [PASP] ≥ 35 mmHg) were prospectively included into this study. In all patients, thoracoscopic LVRS was performed. PASP was assessed by echocardiography before surgery, early postoperatively, and 3 months after surgery. Data were prospectively recorded and analyzed retrospectively. Primary end points were the postoperative changes in PASP as well as the 90 day mortality rate. Secondary endpoints included: pulmonary function test, exercise capacity, quality of life, and dyspnea symptoms (Borg scale). Early after surgery, a significant reduction in PASP was observed at the day of discharge and at 3 month follow-up. In n = 34 patients, no tricuspid valve regurgitation was detectable anymore suggesting normal PAP. In n = 3 patients, venovenous extracorporeal lung support (VV ECLS) was already implemented preoperatively. In the remaining cases, VV ECLS was applied intraoperatively and continued postoperatively. Mean duration of postoperative ECLS support was 2 days. Four patients died due to acute right heart failure, two patients from sepsis with multiorgan failure, and one patient from acute pulmonary embolism. Ninety day mortality was 11.5 %. A significant improvement was postoperatively observed regarding the performance status, dyspnea scale, as well as quality of life. This study suggests a beneficial effect of LVRS on PAP, which may ultimately help to protect and stabilize right ventricular function. Further studies, implementing pre- and postoperative right heart catheterizations including invasive PAP evaluation, are necessary to support the findings in this study in greater detail.

Perioperative Pulmonary Atelectasis: Part I. Biology and Mechanisms

Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.

The physiology and pathophysiology of exercise hyperpnea

In health, the near-eucapnic, highly efficient hyperpnea during mild-to-moderate intensity exercise is driven by three obligatory contributions, namely, feedforward central command from supra-medullary locomotor centers, feedback from limb muscle afferents, and respiratory CO₂ exchange (V̇CO₂). Inhibiting each of these stimuli during exercise elicits a reduction in hyperpnea even in the continuing presence of the other major stimuli. However, the relative contribution of each stimulus to the hyperpnea remains unknown as does the means by which V̇CO2 is sensed. Mediation of the hyperventilatory response to exercise in health is attributed to the multiple feedback and feedforward stimuli resulting from muscle fatigue. In patients with COPD, diaphragm EMG amplitude and its relation to ventilatory output are used to decipher mechanisms underlying the patients' abnormal ventilatory responses, dynamic lung hyperinflation and dyspnea during exercise. Key contributions to these exercise-limiting responses across the spectrum of COPD severity include high dead space ventilation, an excessive neural drive to breathe and highly fatigable limb muscles, together with mechanical constraints on ventilation. Major controversies concerning control of exercise hyperpnea are discussed along with the need for innovative research to uncover the link of metabolism to breathing in health and disease.

Lung Volume Reduction Surgery in Patients with Homogeneous Emphysema

Randomized controlled trials have demonstrated that lung volume reduction surgery (LVRS) improves exercise capacity, lung function, and quality of life in patients with heterogenous emphysema on computed tomographic and perfusion scan. However, most patients have a nonheterogenous type of destruction. These patients, summarized under "homogeneous emphysema," may also benefit from LVRS as long they are severely hyperinflated, and adequate function is remaining with a diffusing capacity of the lungs for carbon monoxide greater than 20% and no pulmonary hypertension. Surgical mortality is low when patients are well selected.

Alpha1-antitrypsin Disease, Treatment and Role for Lung Volume Reduction Surgery

Chronic obstructive pulmonary usually is subcategorized into 2 groups: chronic bronchitis and emphysema. The main cause of chronic bronchitis and emphysema is smoking; however, alpha1-antitrypsin also has been seen to cause emphysema in patients who are deficient. As symptoms and lung function decline, treatment modalities, such as lung volume reduction surgery, have been used in individuals with chronic obstructive pulmonary disease and upper lobe predominant emphysema. This article analyzes multiple published series where lung volume reduction surgery has been used in individuals with alpha1-antitrypsin deficiency and their overall outcomes.

Critical Analysis of the National Emphysema Treatment Trial Results for Lung-Volume-Reduction Surgery

The National Emphysema Treatment Trial compared medical treatment of severe pulmonary emphysema with lung-volume-reduction surgery in a multiinstitutional randomized prospective fashion. Two decades later, this trial remains one of the key sources of information we have on the treatment of advanced emphysematous lung disease. The trial demonstrated the short- and long-term effectiveness of surgical intervention as well as the need for strict patient selection and preoperative workup. Despite these findings, the key failure of the trial was an inability to convince the medical community of the value of surgical resection in the treatment of advanced emphysema.

The Effects of Endobronchial Coil Therapy on Right Ventricular Functions

Lung hyperinflation is an important therapeutic target in symptomatic emphysema patients. Endobronchial therapies that reduce end-expiratory lung volume are increasingly being used in advanced cases. However, there is paucity of data regarding the effects of these therapies on the heart functions. The aim of this study is to evaluate the right ventricular functions before and after the procedure in patients who underwent endobronchial coil therapy (EBCT).Patients who were between 18 and 80 years of age and scheduled for EBCT with GOLD 3-4 were enrolled in the study. Right heart functions were evaluated using MPI, TAS, TAPSE. Right atrium area and maximum velocity of tricuspid regurgitation were also noted.A total of 23 patients were enrolled in the study. 21 patients underwent bilateral intervention, while only 2 patients received unilateral treatment. There was an improvement in MPI (0.49 ± 0.15 vs 0.39 ± 0.11, p < 0.001) and TAS (11.6 (9 - 15) vs 13.2 (9.80 - 17.0), p = 0.001). Peak TRV (2.52 ± 0.6, 2.38 ± 0.6, p = 0.02) and PASP values were lower in the post-operative period (41.15 ± 5.94 vs 36.83 ± 8.01 p = 0.019).In this current study, we found improved echocardiographic RtV parameters in patients who received EBCT treatment.

The effects of lung volume reduction treatment on diffusing capacity and gas exchange

Lung volume reduction (LVR) treatment in patients with severe emphysema has been shown to have a positive effect on hyperinflation, expiratory flow, exercise capacity and quality of life. However, the effects on diffusing capacity of the lungs and gas exchange are less clear. In this review, the possible mechanisms by which LVR treatment can affect diffusing capacity of the lung for carbon monoxide (D _LCO) and arterial gas parameters are discussed, the use of D _LCO in LVR treatment is evaluated and other diagnostic techniques reflecting diffusing capacity and regional ventilation (V')/perfusion (Q') mismatch are considered.A systematic review of the literature was performed for studies reporting on D _LCO and arterial blood gas parameters before and after LVR surgery or endoscopic LVR with endobronchial valves (EBV). D _LCO after these LVR treatments improved (40 studies, n=1855) and the mean absolute change from baseline in % predicted D _LCO was +5.7% (range -4.6% to +29%), with no real change in blood gas parameters. Improvement in V' inhomogeneity and V'/Q' mismatch are plausible explanations for the improvement in D _LCO after LVR treatment.

Emerging Interventional Pulmonary Therapies for Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease is a condition characterized by progressive airflow limitation caused by airway and parenchymal inflammation. Current medical therapies, including bronchodilators, corticosteroids, and anti-inflammatory medications, have been shown to variably improve pulmonary function or quality of life without providing a long-term mortality benefit. Mortality benefits to therapy have been demonstrated in only 2 therapeutic interventions to date: long-term use of daily supplemental oxygen and surgical lung volume reduction (LVRS) for upper-lobe-predominant disease in patients with a low baseline exercise capacity. Newer bronchoscopic techniques for lung volume reduction (bLVR) have attracted interest from clinicians and researchers. To achieve successful results, these advanced therapies require an interdisciplinary approach between general and interventional pulmonologists and thoracic radiologists. In this article, we aim to review the latest interventional pulmonary techniques for treatment of chronic obstructive pulmonary disease with an emphasis on bLVR. We will review the bLVR preprocedure imaging evaluation, postprocedure imaging findings, and explore the potential benefits and risks of therapy based on the most recent clinical trial evidence.

COMBORIDITY OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND CARDIOVASCULAR DISEASES: GENERAL FACTORS, PATHOPHYSIOLOGICAL MECHANISMS AND CLINICAL SIGNIFICANCE

Currently, the comorbidity (combination) of chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVD) is an relevant problem for health care. This is due to the high prevalence and continued growth of these pathologies. CVD and COPD have common risk factors and mechanisms underlying their development and progression: smoking, inflammation, sedentary lifestyle, aging, oxidative stress, air pollution, and hypoxia. In this review, we summarize current knowledge relating to the prevalence and frequency of cardiovascular diseases in people with COPD and the mechanisms that underlie their coexistence. The implications for clinical practice, in particular the main problems of diagnosis and treatment of COPD/CVD comorbidity, are also discussed.

Bronchoscopic device intervention in chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease is a heterogeneous syndrome associated with varying degrees of parenchymal emphysema and airway inflammation resulting in decreased expiratory flow, lung hyperinflation, and symptoms leading to decreased exercise tolerance and quality of life. Impairment in lung function and quality of life persists following guideline-based medical therapy, thus surgical and minimally invasive bronchoscopic approaches were developed to address this unmet need. We offer a narrative review of the available technologies.

RECENT FINDINGS

Although lung volume reduction surgery has been shown to improve survival in appropriately selected patients, it is infrequently performed. Less invasive bronchoscopic procedures have thus been explored including endobronchial valves, coils, lung sealant, thermal vapor, and other airway approaches. Selection criteria including severity of physiologic and radiographic impairment, degree of lung hyperinflation, presence of intact fissures, type of symptoms, and presence of comorbidities are critical in selecting appropriate candidates.

SUMMARY

Recent advances in minimally invasive approaches to lung volume reduction have offered alternatives to surgical approaches. Two endobronchial valve devices are Food and Drug Administration approved for clinical use, and investigations into alternative bronchoscopic therapies to treat both emphysema and chronic bronchitis have been performed or are currently underway. Notably, each of these treatments requires unique selection criteria and thus a personalized approach to treatment.

A Multicenter Randomized Controlled Trial of Zephyr Endobronchial Valve Treatment in Heterogeneous Emphysema (LIBERATE)

RATIONALE

This is the first multicenter randomized controlled trial to evaluate the effectiveness and safety of Zephyr Endobronchial Valve (EBV) in patients with little to no collateral ventilation out to 12 months.

OBJECTIVES

To evaluate the effectiveness and safety of Zephyr EBV in heterogeneous emphysema with little to no collateral ventilation in the treated lobe.

METHODS

Subjects were enrolled with a 2:1 randomization (EBV/standard of care [SoC]) at 24 sites. Primary outcome at 12 months was the ΔEBV-SoC of subjects with a post-bronchodilator FEV₁ improvement from baseline of greater than or equal to 15%. Secondary endpoints included absolute changes in post-bronchodilator FEV₁, 6-minute-walk distance, and St. George's Respiratory Questionnaire scores.

MEASUREMENTS AND MAIN RESULTS

A total of 190 subjects (128 EBV and 62 SoC) were randomized. At 12 months, 47.7% EBV and 16.8% SoC subjects had a ΔFEV₁ greater than or equal to 15% (P < 0.001). ΔEBV-SoC at 12 months was statistically and clinically significant: for FEV₁, 0.106 L (P < 0.001); 6-minute-walk distance, +39.31 m (P = 0.002); and St. George's Respiratory Questionnaire, -7.05 points (P = 0.004). Significant ΔEBV-SoC were also observed in hyperinflation (residual volume, -522 ml; P < 0.001), modified Medical Research Council Dyspnea Scale (-0.8 points; P < 0.001), and the BODE (body mass index, airflow obstruction, dyspnea, and exercise capacity) index (-1.2 points). Pneumothorax was the most common serious adverse event in the treatment period (procedure to 45 d), in 34/128 (26.6%) of EBV subjects. Four deaths occurred in the EBV group during this phase, and one each in the EBV and SoC groups between 46 days and 12 months.

CONCLUSIONS

Zephyr EBV provides clinically meaningful benefits in lung function, exercise tolerance, dyspnea, and quality of life out to at least 12 months, with an acceptable safety profile in patients with little or no collateral ventilation in the target lobe. Clinical trial registered with www.clinicaltrials.gov (NCT 01796392).

Strain measurement on four-dimensional dynamic-ventilation CT: quantitative analysis of abnormal respiratory deformation of the lung in COPD

Purpose

Strain measurement is frequently used to assess myocardial motion in cardiac imaging. This study aimed to apply strain measurement to pulmonary motion observed by four-dimensional dynamic-ventilation computed tomography (CT) and to clarify motion abnormality in COPD.

Materials and methods

Thirty-two smokers, including ten with COPD, underwent dynamic-ventilation CT during spontaneous breathing. CT data were continuously reconstructed every 0.5 seconds. In the series of images obtained by dynamic-ventilation CT, five expiratory frames were identified starting from the peak inspiratory frame (first expiratory frame) and ending with the fifth expiratory frame. Strain measurement of the scanned lung was performed using research software that was originally developed for cardiac strain measurement and modified for assessing deformation of the lung. The measured strain values were divided by the change in mean lung density to adjust for the degree of expiration. Spearman’s rank correlation analysis was used to evaluate associations between the adjusted strain measurements and various spirometric values.

Results

The adjusted strain measurement was negatively correlated with FEV₁/FVC (ρ=−0.52, P<0.01), maximum mid-expiratory flow (ρ=−0.59, P<0.001), and peak expiratory flow (ρ=−0.48, P<0.01), suggesting that abnormal deformation of lung motion is related to various patterns of expiratory airflow limitation.

Conclusion

Abnormal deformation of lung motion exists in COPD patients and can be quantitatively assessed by strain measurement using dynamic-ventilation CT. This technique can be expanded to dynamic-ventilation CT in patients with various lung and airway diseases that cause abnormal pulmonary motion.

Patient Preferences for Endobronchial Valve Treatment of Severe Emphysema

Background: Patients with severe emphysema have limited treatment options. Little is known about patients' willingness to accept risks for new treatments that offer meaningful benefits. Methods: We determined treatment preferences of patients with severe emphysema using a web-based discrete-choice experiment survey. Respondents answered 9 questions that offered choices between 2 hypothetical interventional treatments or continuing current medical management. Variations in 5 attributes defined the 2 interventional treatments: improvement in ability to breathe and carry out day-to-day activities, frequency of hospitalized exacerbations, treatment type, risk of pneumothorax within 30 days of procedure, and risk of death within 3 months. Respondents were recruited through the COPD Foundation's COPD Patient-Powered Research Network and had a self-reported emphysema diagnosis and 2+ score on the modified Medical Research Council Dyspnea Scale. The relative importance of the attributes and the percentage of respondents who would select different treatment options was modeled using random-parameters logit. Results: Among 294 respondents, 51% always chose an interventional treatment option, while 19% always selected continued medical management. The most important change on average was moving from continued medical management (with no improvement in breathlessness) to an interventional treatment with improvement in breathlessness. The model predicted 71% of respondents would select a treatment option similar to removable endobronchial valve implants, 6% would select lung volume reduction surgery (LVRS), and 23% continued medical management. Conclusion: Patients with severe emphysema perceive that a procedure with risks and benefits similar to the Zephyr^® endobronchial valve implants is desirable over continued medical management or LVRS.

Effect of Lung Volume Reduction Surgery on Respiratory Muscle Strength in Advanced Emphysema

Background: Long-term effects of lung volume reduction surgery (LVRS) on respiratory muscle strength and effects of age, sex, and emphysema pattern on these changes are unknown. Therefore, we aimed to determine the long-term effect of LVRS on respiratory muscle strength changes in severe emphysema. Methods: The National Emphysema Treatment Trial was a prospective controlled multicentered trial, comparing LVRS to optimal medical treatment on survival and maximal exercise capacity. We examined percentage change in maximum inspiratory pressure (MIP) from baseline to 36 months follow-up to determine impact of LVRS as well as age, sex, emphysema pattern and exercise capacity on changes in MIP compared to medical treatment. Results: LVRS individuals had significantly greater increases in MIP from baseline compared to medical individuals at all follow-ups (LVRS 19.8 ± 42.3%, medical 3.2 ± 29.3%, p<0.0001, 12 months). The LVRS group had significant decreases in total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC) and RV/TLC compared to the medical arm at all follow-up periods. Males and individuals 65-70 years of age had significantly greater increases in MIP following LVRS compared to the medical arm at all follow-ups; this same relationship was seen at up to 24 months for low exercise capacity, upper lobe predominant emphysema. Conclusions: LVRS significantly increases inspiratory muscle strength up to 3 years post-operatively, with male sex, age 65-70 years and low exercise capacity, upper lobe predominant emphysema especially associated with increased MIP. Inspiratory muscle strength increases were associated with decreases in non-invasive markers of dynamic hyperinflation, suggesting that LVRS allows inspiratory muscles to return to their optimal length-tension relationship.

Can we estimate transpulmonary pressure without an esophageal balloon?-yes

A protective ventilation strategy is based on separation of lung and chest wall mechanics and determination of transpulmonary pressure. So far, this has required esophageal pressure measurement, which is cumbersome, rarely used clinically and associated with lack of consensus on the interpretation of measurements. We have developed an alternative method based on a positive end expiratory pressure (PEEP) step procedure where the PEEP-induced change in end-expiratory lung volume is determined by the ventilator pneumotachograph. In pigs, lung healthy patients and acute lung injury (ALI) patients, it has been verified that the determinants of the change in end-expiratory lung volume following a PEEP change are the size of the PEEP step and the elastic properties of the lung, ∆PEEP × Clung. As a consequence, lung compliance can be calculated as the change in end-expiratory lung volume divided by the change in PEEP and esophageal pressure measurements are not needed. When lung compliance is determined in this way, transpulmonary driving pressure can be calculated on a breath-by-breath basis. As the end-expiratory transpulmonary pressure increases as much as PEEP is increased, it is also possible to determine the end-inspiratory transpulmonary pressure at any PEEP level. Thus, the most crucial factors of ventilator induced lung injury can be determined by a simple PEEP step procedure. The measurement procedure can be repeated with short intervals, which makes it possible to follow the course of the lung disease closely. By the PEEP step procedure we may also obtain information (decision support) on the mechanical consequences of changes in PEEP and tidal volume performed to improve oxygenation and/or carbon dioxide removal.

Pulmonary hypertension in chronic obstructive pulmonary disease and emphysema patients: prevalence, therapeutic options and pulmonary circulatory effects of lung volume reduction surgery

The exact prevalence of pulmonary hypertension (PH) and cor pulmonale (CP) in chronic obstructive pulmonary disease (COPD) is unknown, and varies considerably from 20-91%. Usually, mean pulmonary artery pressure (mPAP) does not exceed 30 mmHg, and PH is not severe. However, PH and CP are important predictors of mortality in COPD and contribute to disability in this disease. Many factors contribute to the development of PH in chronic lung disease, including reduction of the pulmonary vascular cross-sectional area due to parenchymal loss and accompanying hypoxia, effects of abnormal pulmonary mechanics due to hyperinflation, but also vascular remodeling processes. So far, PH associated with chronic lung disease cannot be treated medically. Therefore, it is indicated to treat the underlying pulmonary disease. Patients with severe PH should be referred to centers experienced in the management of PH and enrollment in clinical trials should be considered. Lung volume reduction surgery (LVRS) theoretically further increases pulmonary vascular resistance (PVR) by reducing the vascular bed when resecting lung tissue, however, this might be compensated by better pulmonary mechanics through reduction of hyperinflation, which will be discussed in the present article.

Lung volume reduction surgery beyond the NETT selection criteria

Lung volume reduction surgery (LVRS) for symptomatic patients with advanced emphysema was proven to be successful in a large randomized multi-center trial (NETT) and in several smaller randomized single center trials. This evidence primarily concerns patients with heterogeneous, upper-lobe predominant emphysema and low exercise tolerance within certain selection criteria regarding lung function values. As the most important effect of LVRS is generated by reducing the hyperinflation, even patients with homogeneous emphysema morphology profit from the procedure. Simultaneously, by removing distended and functionless areas in heterogeneous emphysema, also patients with seriously impaired diffusion capacity, moderate pulmonary arterial hypertension, a history of previous LVRS and alpha-1-antitrypsin-deficiency (AATD) can be considered as candidates for (re-)-LVRS. This article summarizes indications for LVRS in these various subtypes of emphysema patients.

Valve therapy in patients with emphysematous type of chronic obstructive pulmonary disease (COPD): from randomized trials to patient selection in clinical practice

In recent years a number of endoscopic methods have emerged to treat patients with severe emphysematous type of chronic obstructive pulmonary disease (COPD), who are primarily symptomatic due to hyperinflation despite optimal medical management. Of these techniques, implantation of endobronchial one-way valves into targeted airways of isolated emphysematous lobes appears to be one of the most promising innovations. Results from randomized controlled trials of valve therapy for emphysema show consistent benefits in terms of lung function, exercise capacity, symptoms, and quality of life. This review aims to provide a comprehensive summary of the currently available scientific data, discussion of typical treatment related side effects, and recommendations for patient selection in clinical practice.

The Link between Reduced Inspiratory Capacity and Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Low inspiratory capacity (IC), chronic dyspnea, and reduced exercise capacity are inextricably linked and are independent predictors of increased mortality in chronic obstructive pulmonary disease. It is no surprise, therefore, that a major goal of management is to improve IC by reducing lung hyperinflation to improve respiratory symptoms and health-related quality of life. The negative effects of lung hyperinflation on respiratory muscle and cardiocirculatory function during exercise are now well established. Moreover, there is growing appreciation that a key mechanism of exertional dyspnea in chronic obstructive pulmonary disease is critical mechanical constraints on tidal volume expansion during exercise when resting IC is reduced. Further evidence for the importance of lung hyperinflation comes from multiple studies, which have reported the clinical benefits of therapeutic interventions that reduce lung hyperinflation and increase IC. A reduced IC in obstructive pulmonary disease is further eroded by exercise and contributes to ventilatory limitation and dyspnea. It is an important outcome for both clinical and research studies.

Lung Volume Reduction Surgery for Respiratory Failure in Infants With Bronchopulmonary Dysplasia

Lung volume reduction surgery (LVRS) can be performed in patients with severe emphysematous disease. However, LVRS in pediatric patients has not yet been reported. Here, we report our experience with 2 cases of pediatric LVRS. The first patient was a preterm infant girl with severe bronchopulmonary dysplasia, pulmonary hypertension, and hypothyroidism. The emphysematous portion of the right lung was removed via sternotomy and right hemiclamshell incision. The patient was discharged on full-time home ventilator support for 3 months after the surgery. Since then, her respiratory function has improved continuously. She no longer needs oxygen supplementation or ventilator care. Her T-cannula was removed recently. The second patient was also a preterm infant girl with bronchopulmonary dysplasia. She was born with pulmonary hypertension and multiple congenital anomalies, including an atrial septal defect. Despite receiving the best supportive care, she could not be taken off the mechanical ventilator because of severe hypercapnia. We performed LVRS on the right lung via thoracotomy. She was successfully weaned off the mechanical ventilator 1 month after the surgery. She was discharged without severe complications at 3 months after the operation. At present, she is growing well with the help of intermittent home ventilator support. She can now tolerate an oral diet. Our experience shows that LVRS can be considered as a treatment option for pediatric patients with severe emphysematous lung. It is especially helpful for discontinuing prolonged mechanical ventilator care for patients with respiratory failure.

Defining the relationship between COPD and CVD: what are the implications for clinical practice?

Cardiovascular diseases (CVDs) are arguably the most important comorbidities in chronic obstructive pulmonary disease (COPD). CVDs are common in people with COPD, and their presence is associated with increased risk for hospitalization, longer length of stay and all-cause and CVD-related mortality. The economic burden associated with CVD in this population is considerable and the cumulative cost of treating comorbidities may even exceed that of treating COPD itself. Our understanding of the biological mechanisms that link COPD and various forms of CVD has improved significantly over the past decade. But despite broad acceptance of the prognostic significance of CVDs in COPD, there remains widespread under-recognition and undertreatment of comorbid CVD in this population. The reasons for this are unclear; however institutional barriers and a lack of evidence-based guidelines for the management of CVD in people with COPD may be contributory factors. In this review, we summarize current knowledge relating to the prevalence and incidence of CVD in people with COPD and the mechanisms that underlie their coexistence. We discuss the implications for clinical practice and highlight opportunities for improved prevention and treatment of CVD in people with COPD. While we advocate more active assessment for signs of cardiovascular conditions across all age groups and all stages of COPD severity, we suggest targeting those aged under 65 years. Evidence indicates that the increased risks for CVD are particularly pronounced in COPD patients in mid-to-late-middle-age and thus it is in this age group that the benefits of early intervention may prove to be the most effective.

Hyperinflated lungs compress the heart during expiration in COPD patients: a new finding on dynamic-ventilation computed tomography

Purpose

The aims of this study were to evaluate dynamic changes in heart size during the respiratory cycle using four-dimensional computed tomography (CT) and to understand the relationship of these changes to airflow limitation in smokers.

Materials and methods

A total of 31 smokers, including 13 with COPD, underwent four-dimensional dynamic-ventilation CT during regular breathing. CT data were continuously reconstructed every 0.5 s, including maximum cross-sectional area (CSA) of the heart and mean lung density (MLD). Concordance between the cardiac CSA and MLD time curves was expressed by cross-correlation coefficients. The CT-based cardiothoracic ratio at inspiration and expiration was also calculated. Comparisons of the CT indices between COPD patients and non-COPD smokers were made using the Mann–Whitney test. Spearman rank correlation analysis was used to evaluate associations between CT indices and the forced expiratory volume in 1 s (FEV_1.0) relative to the forced vital capacity (FVC).

Results

Cardiac CSA at both inspiration and expiration was significantly smaller in COPD patients than in non-COPD smokers (P<0.05). The cross-correlation coefficient between cardiac CSA and MLD during expiration significantly correlated with FEV_1.0/FVC (ρ=0.63, P<0.001), suggesting that heart size decreases during expiration in COPD patients. The change in the cardiothoracic ratio between inspiration and expiration frames was significantly smaller in COPD patients than in non-COPD smokers (P<0.01).

Conclusion

Patients with COPD have smaller heart size on dynamic-ventilation CT than non-COPD smokers and have abnormal cardiac compression during expiration.

Changes in dynamic lung mechanics after lung volume reduction coil treatment of severe emphysema

We assessed the relationships between changes in lung compliance, lung volumes and dynamic hyperinflation in patients with emphysema who underwent bronchoscopic treatment with nitinol coils (coil treatment) (n=11) or received usual care (UC) (n=11). Compared with UC, coil treatment resulted in decreased dynamic lung compliance (C_Ldyn) (p=0.03) and increased endurance time (p=0.010). The change in C_Ldyn was associated with significant improvement in FEV₁ and FVC, with reduction in residual volume and intrinsic positive end-expiratory pressure, and with increased inspiratory capacity at rest/and at exercise. The increase in end-expiratory lung volume (EELV) during exercise (EELV_dyn-ch=EELV_isotime EELV_rest) demonstrated significant attenuation after coil treatment (p=0.02).

Endobronchial Valve Therapy in Patients with Homogeneous Emphysema. Results from the IMPACT Study

RATIONALE

Endobronchial valves (EBVs) have been successfully used in patients with severe heterogeneous emphysema to improve lung physiology. Limited available data suggest that EBVs are also effective in homogeneous emphysema.

OBJECTIVES

To evaluate the efficacy and safety of EBVs in patients with homogeneous emphysema with absence of collateral ventilation assessed with the Chartis system.

METHODS

Prospective, multicenter, 1:1 randomized controlled trial of EBV plus standard of care (SoC) or SoC alone. Primary outcome was the percentage change in FEV₁ (liters) at 3 months relative to baseline in the EBV group versus the SoC group. Secondary outcomes included changes in FEV₁, St. George's Respiratory Questionnaire (SGRQ), 6-minute-walk distance (6MWD), and target lobe volume reduction.

MEASUREMENTS AND MAIN RESULTS

Ninety-three subjects (age, 63.7 ± 6.1 yr [mean ± SD]; FEV₁, % predicted, 29.3 ± 6.5; residual volume, % predicted, 275.4 ± 59.4) were allocated to either the EBV group (n = 43) or the SoC group (n = 50). In the intention-to-treat population, at 3 months postprocedure, improvement in FEV₁ from baseline was 13.7 ± 28.2% in the EBV group and -3.2 ± 13.0% in the SoC group (mean between-group difference, 17.0%; P = 0.0002). Other variables demonstrated statistically and clinically significant changes from baseline to 3 months (EBV vs. SoC, respectively: SGRQ, -8.63 ± 11.25 vs. 1.01 ± 9.36; and 6MWD, 22.63 ± 66.63 m vs. -17.34 ± 52.8 m). Target lobe volume reduction at 3 months was -1,195 ± 683 ml (P < 0.0001). Of the EBV subjects, 97.2% achieved volume reduction in the target lobe (P < 0.0001). Procedure-related pneumothoraces occurred in 11 subjects (25.6%). Five subjects required removal/replacement of one or more valves. One subject experienced two valve migration events requiring removal/replacement of valves.

CONCLUSIONS

EBV in patients with homogeneous emphysema without collateral ventilation results in clinically meaningful benefits of improved lung function, exercise tolerance, and quality of life.

Improvement in Ventilation-Perfusion Mismatch after Bronchoscopic Lung Volume Reduction: Quantitative Image Analysis

Purpose To evaluate whether bronchoscopic lung volume reduction (BLVR) increases ventilation and therefore improves ventilation-perfusion (V/Q) mismatch. Materials and Methods All patients provided written informed consent to be included in this study, which was approved by the Institutional Review Board (2013-0368) of Asan Medical Center. The physiologic changes that occurred after BLVR were measured by using xenon-enhanced ventilation and iodine-enhanced perfusion dual-energy computed tomography (CT). Patients with severe emphysema plus hyperinflation who did not respond to usual treatments were eligible. Pulmonary function tests, the 6-minute walking distance (6MWD) test, quality of life assessment, and dual-energy CT were performed at baseline and 3 months after BLVR. The effect of BLVR was assessed with repeated-measures analysis of variance. Results Twenty-one patients were enrolled in this study (median age, 68 years; mean forced expiratory volume in 1 second [FEV₁], 0.75 L ± 0.29). After BLVR, FEV₁ (P < .001) and 6MWD (P = .002) improved significantly. Despite the reduction in lung volume (-0.39 L ± 0.44), both ventilation per voxel (P < .001) and total ventilation (P = .01) improved after BLVR. However, neither perfusion per voxel (P = .16) nor total perfusion changed significantly (P = .49). Patients with lung volume reduction of 50% or greater had significantly better improvement in FEV₁ (P = .02) and ventilation per voxel (P = .03) than patients with lung volume reduction of less than 50%. V/Q mismatch also improved after BLVR (P = .005), mainly owing to the improvement in ventilation. Conclusion The dual-energy CT analyses showed that BLVR improved ventilation and V/Q mismatch. This increased lung efficiency may be the primary mechanism of improvement after BLVR, despite the reduction in lung volume. ^© RSNA, 2017 Online supplemental material is available for this article.

Three-dimensional computed tomographic volumetry precisely predicts the postoperative pulmonary function

PURPOSE

It is important to accurately predict the patient's postoperative pulmonary function. The aim of this study was to compare the accuracy of predictions of the postoperative residual pulmonary function obtained with three-dimensional computed tomographic (3D-CT) volumetry with that of predictions obtained with the conventional segment-counting method.

METHODS

Fifty-three patients scheduled to undergo lung cancer resection, pulmonary function tests, and computed tomography were enrolled in this study. The postoperative residual pulmonary function was predicted based on the segment-counting and 3D-CT volumetry methods. The predicted postoperative values were compared with the results of postoperative pulmonary function tests.

RESULTS

Regarding the linear correlation coefficients between the predicted postoperative values and the measured values, those obtained using the 3D-CT volumetry method tended to be higher than those acquired using the segment-counting method. In addition, the variations between the predicted and measured values were smaller with the 3D-CT volumetry method than with the segment-counting method. These results were more obvious in COPD patients than in non-COPD patients.

CONCLUSIONS

Our findings suggested that the 3D-CT volumetry was able to predict the residual pulmonary function more accurately than the segment-counting method, especially in patients with COPD. This method might lead to the selection of appropriate candidates for surgery among patients with a marginal pulmonary function.

Is preoperative hypercapnia a justified exclusion criterion for lung volume reduction surgery?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether potential surgical candidates for lung volume reduction surgery (LVRS), who have preoperative hypercapnia, should be excluded on this basis. Using the reported search, 45 papers were found, of which 14 represented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses were tabulated. Of these, seven papers showed a significant (P < 0.05) improvement in postoperative forced expiratory volume in 1 second (FEV1) at up to 6 months in hypercapnic patients. There were six papers which found significant decreases in postoperative arterial carbon dioxide partial pressures (PaCO2) levels following LVRS up to 6 months. There were three papers which showed significant (P < 0.05) improvements in the 6-min walk test in hypercapnic patients following LVRS. Only two papers showed an increased operative mortality in the hypercapnic group compared to the normocapnic group, while nine papers did not find a difference in perioperative mortality. The only randomized controlled study, the landmark NETT study, excluded patients with severe hypercapnia (PaCO2 >55 mmHg and >60 mmHg) and the mean PaCO2 in the surgical and medical group were 43.3 ± 5.9 and 43.0 ± 5.8, respectively. We conclude that the evidence is not strong enough to consider hypercapnia in isolation as high risk or unsuitable for LVRS.

Lung volume reduction surgery for diffuse emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) performed to treat patients with severe diffuse emphysema was reintroduced in the nineties. Lung volume reduction surgery aims to resect damaged emphysematous lung tissue, thereby increasing elastic properties of the lung. This treatment is hypothesised to improve long-term daily functioning and quality of life, although it may be costly and may be associated with risks of morbidity and mortality. Ten years have passed since the last version of this review was prepared, prompting us to perform an update.

OBJECTIVES

The objective of this review was to gather all available evidence from randomised controlled trials comparing the effectiveness of lung volume reduction surgery (LVRS) versus non-surgical standard therapy in improving health outcomes for patients with severe diffuse emphysema. Secondary objectives included determining which subgroup of patients benefit from LVRS and for which patients LVRS is contraindicated, to establish the postoperative complications of LVRS and its morbidity and mortality, to determine which surgical approaches for LVRS are most effective and to calculate the cost-effectiveness of LVRS.

SEARCH METHODS

We identified RCTs by using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register, in addition to the online clinical trials registers. Searches are current to April 2016.

SELECTION CRITERIA

We included RCTs that studied the safety and efficacy of LVRS in participants with diffuse emphysema. We excluded studies that investigated giant or bullous emphysema.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed trials for inclusion and extracted data. When possible, we combined data from more than one study in a meta-analysis using RevMan 5 software.

MAIN RESULTS

We identified two new studies (89 participants) in this updated review. A total of 11 studies (1760 participants) met the entry criteria of the review, one of which accounted for 68% of recruited participants. The quality of evidence ranged from low to moderate owing to an unclear risk of bias across many studies, lack of blinding and low participant numbers for some outcomes. Eight of the studies compared LVRS versus standard medical care, one compared two closure techniques (stapling vs laser ablation), one looked at the effect of buttressing the staple line on the effectiveness of LVRS and one compared traditional 'resectional' LVRS with a non-resectional surgical approach. Participants completed a mandatory course of pulmonary rehabilitation/physical training before the procedure commenced. Short-term mortality was higher for LVRS (odds ratio (OR) 6.16, 95% confidence interval (CI) 3.22 to 11.79; 1489 participants; five studies; moderate-quality evidence) than for control, but long-term mortality favoured LVRS (OR 0.76, 95% CI 0.61 to 0.95; 1280 participants; two studies; moderate-quality evidence). Participants identified post hoc as being at high risk of death from surgery were those with particularly impaired lung function, poor diffusing capacity and/or homogenous emphysema. Participants with upper lobe-predominant emphysema and low baseline exercise capacity showed the most favourable outcomes related to mortality, as investigators reported no significant differences in early mortality between participants treated with LVRS and those in the control group (OR 0.87, 95% CI 0.23 to 3.29; 290 participants; one study), as well as significantly lower mortality at the end of follow-up for LVRS compared with control (OR 0.45, 95% CI 0.26 to 0.78; 290 participants; one study). Trials in this review furthermore provided evidence of low to moderate quality showing that improvements in lung function parameters other than forced expiratory volume in one second (FEV1), quality of life and exercise capacity were more likely with LVRS than with usual follow-up. Adverse events were more common with LVRS than with control, specifically the occurrence of (persistent) air leaks, pulmonary morbidity (e.g. pneumonia) and cardiovascular morbidity. Although LVRS leads to an increase in quality-adjusted life-years (QALYs), the procedure is relatively costly overall.

AUTHORS' CONCLUSIONS

Lung volume reduction surgery, an effective treatment for selected patients with severe emphysema, may lead to better health status and lung function outcomes, specifically for patients who have upper lobe-predominant emphysema with low exercise capacity, but the procedure is associated with risks of early mortality and adverse events.

Overview of the Novel and Improved Pulmonary Ventilation-Perfusion Imaging Applications in the Era of SPECT/CT

OBJECTIVE

In this article, we describe the concepts of ventilation-perfusion planar, SPECT, and SPECT/CT and outline the advantages of integrated ventilation-perfusion SPECT/CT over planar imaging. We present an overview of the traditional and new applications of ventilation-perfusion scintigraphy.

CONCLUSION

SPECT/CT has improved the diagnostic accuracy of ventilation-perfusion imaging and opened the door for a new spectrum of applications.

Transpulmonary and pleural pressure in a respiratory system model with an elastic recoiling lung and an expanding chest wall

Background

We have shown in acute lung injury patients that lung elastance can be determined by a positive end-expiratory pressure (PEEP) step procedure and proposed that this is explained by the spring-out force of the rib cage off-loading the chest wall from the lung at end-expiration. The aim of this study was to investigate the effect of the expanding chest wall on pleural pressure during PEEP inflation by building a model with an elastic recoiling lung and an expanding chest wall complex.

Methods

Test lungs with a compliance of 19, 38, or 57 ml/cmH₂O were placed in a box connected to a plastic container, 3/4 filled with water, connected to a water sack of 10 l, representing the abdomen. The space above the water surface and in the lung box constituted the pleural space. The contra-directional forces of the recoiling lung and the expanding chest wall were obtained by evacuating the pleural space to a negative pressure of 5 cmH₂O. Chest wall elastance was increased by strapping the plastic container. Pressure was measured in the airway and pleura. Changes in end-expiratory lung volume (ΔEELV), during PEEP steps of 4, 8, and 12 cmH₂O, were determined in the isolated lung, where airway equals transpulmonary pressure and in the complete model as the cumulative inspiratory-expiratory tidal volume difference. Transpulmonary pressure was calculated as airway minus pleural pressure.

Results

Lung pressure/volume curves of an isolated lung coincided with lung P/V curves in the complete model irrespective of chest wall stiffness. ΔEELV was equal to the size of the PEEP step divided by lung elastance (EL), ΔEELV = ΔPEEP/EL. The end-expiratory “pleural” pressure did not increase after PEEP inflation, and consequently, transpulmonary pressure increased as much as PEEP was increased.

Conclusions

The rib cage spring-out force causes off-loading of the chest wall from the lung and maintains a negative end-expiratory “pleural” pressure after PEEP inflation. The behavior of the respiratory system model confirms that lung elastance can be determined by a simple PEEP step without using esophageal pressure measurements.

Reduction in resting energy expenditure following lung volume reduction surgery in subjects with chronic obstructive pulmonary disease

Study objectives: Some subjects with COPD have an elevated resting energy expenditure (REE)which may be related to an increased work of breathing at rest. The purpose of this study was to examine the effect of lung volume reduction surgery (LVRS) on REE and body weight. Design: Ten subjects with COPD were recruited (mean age + SD = 61.4 + 6.1 years). At baseline (which was following preoperative pulmonary rehabilitation) and four months following LVRS (combined with postoperative pulmonary rehabilitation), each subject had tests of lung function, REE via indirect calorimetry using a canopy system, six minute walk distance (6MWD) and quality of life (QoL) using the St George's Hospital Respiratory Questionnaire (SGRQ). Measurements: The FEV, (% predicted) increased from 27.7 + 5.8% (mean + SD) at baseline to 33.9 + 7.8% following LVRS (P < 0.05). REE (% predicted) was 110 + 9.8% at baseline and decreased to 106 + 6.7% following LVRS (P = 0.04). Body mass index (BMI) following LVRS was unchanged (P = 0.67). No correlation between the change in BMI and change in REE was shown (r2 = 0.3, P = 0.1). Therewas a significant improvement in QoL following LVRS (P < 0.001). 6MWD also significantly increased from 354 + 83 m to 412 + 82 m following LVRS (P = 0.001). Conclusion: Whilst there was an increase in lung function and a reduction in REE following LVRS, there was no corresponding change to body weight. The improvement in REE following LVRS may be related to an improvement in work of breathing.

Supported and unsupported arm exercise capacity following lung volume reduction surgery: a pilot study

Study Objectives: Lung volume reduction surgery (LVRS) has been shown to improve lung function, leg exercise capacity and quality of life in subjects with severe COPD. This is the first study to examine the effect of LVRS on supported and unsupported arm exercise capacity. Design: Eight subjects with COPD (% pred FEV1 ±SD = 31.1 ± 9.8%) completed testing. At baseline (TI), after eight weeks pulmonary rehabilitation (T2) and four months after LVRS (T3), each subject had tests of lung function, and performed three symptom-limited exercise tests to peak work capacity:supported arm exercise (SAE), unsupported arm exercise (UAE) and leg exercise (LE).Measurements: The FEV1 (% pred) increased from 27.8 ± 7.4 (mean ± SD) at T2 to 36.3 ± 7.1 at T3 (P <0.05). Peak oxygen consumption (VO2) remained similar from TI to T2 for SAE, UAE and LE (all P=1.0) but increased from T2 to T3 (P <0.05) (SAE: T2 = 0.59 ± 0.2 L/min,T3 = 0.72 ± 0.1 L/min; UAE: T2 = 0.45 ± 0.1 L/min, T3 = 0.54 ± 0.1 L/min; LE:T2-0.68 ± 0.2 L/min, T3 = 0.81 ± 0.2 L/min). The ratio of end-expiratory lung volume to total lung capacity was reduced at peak SAE and LE from T2 to T3 (P < 0.01) (SAE:T2 = 81 ± 4.0%, T3 = 76 ± 2.7%; LE: T2-81 ± 5.1%, T3 = 75 ± 3.6%). Conclusion: There was a significant increase in SAE and UAE capacity following LVRS. Dynamic hyperinflation wras reduced during SAE following LVRS.

Current Controversies in Surgical Therapy for Emphysema

Interest in surgical therapy for emphysema has grown phenomenally since the reintroduction of lung volume reduction surgery (LVRS). Although early results have shown promise, important controversies have also emerged. Some of the central issues include refining patient selection criteria, identifying optimal measure ments of improvement after LVRS, achieving a more complete understanding of the functional consequences after LVRS, and, most importantly, identifying the effect of LVRS, an admittedly palliative procedure, on disease progression and mortality in emphysema. Secondary issues surrounding LVRS include its role in combination with other procedures and its potentially large eco nomic impact. The National Emphysema Treatment Trial, a joint effort between the National Heart, Lung, and Blood Institute and the Health Care Financing Administration, is designed to address and clarify these and other questions about LVRS.

Lung Deflation and Cardiovascular Structure and Function in Chronic Obstructive Pulmonary Disease. A Randomized Controlled Trial

RATIONALE

Patients with chronic obstructive pulmonary disease develop increased cardiovascular morbidity with structural alterations.

OBJECTIVES

To investigate through a double-blind, placebo-controlled, crossover study the effect of lung deflation on cardiovascular structure and function using cardiac magnetic resonance.

METHODS

Forty-five hyperinflated patients with chronic obstructive pulmonary disease were randomized (1:1) to 7 (maximum 14) days inhaled corticosteroid/long-acting β2-agonist fluticasone furoate/vilanterol 100/25 μg or placebo (7-day minimum washout). Primary outcome was change from baseline in right ventricular end-diastolic volume index versus placebo.

MEASUREMENTS AND MAIN RESULTS

There was a 5.8 ml/m(2) (95% confidence interval, 2.74-8.91; P < 0.001) increase in change from baseline right ventricular end-diastolic volume index and a 429 ml (P < 0.001) reduction in residual volume with fluticasone furoate/vilanterol versus placebo. Left ventricular end-diastolic and left atrial end-systolic volumes increased by 3.63 ml/m(2) (P = 0.002) and 2.33 ml/m(2) (P = 0.002). In post hoc analysis, right ventricular stroke volume increased by 4.87 ml/m(2) (P = 0.003); right ventricular ejection fraction was unchanged. Left ventricular adaptation was similar; left atrial ejection fraction improved by +3.17% (P < 0.001). Intrinsic myocardial function was unchanged. Pulmonary artery pulsatility increased in two of three locations (main +2.9%, P = 0.001; left +2.67%, P = 0.030). Fluticasone furoate/vilanterol safety profile was similar to placebo.

CONCLUSIONS

Pharmacologic treatment of chronic obstructive pulmonary disease has consistent beneficial and plausible effects on cardiac function and pulmonary vasculature that may contribute to favorable effects of inhaled therapies. Future studies should investigate the effect of prolonged lung deflation on intrinsic myocardial function. Clinical trial registered with www.clinicaltrials.gov (NCT 01691885).

Transcutaneous carbon-dioxide partial pressure trends during six-minute walk test in patients with very severe COPD

BACKGROUND

Transcutaneous carbon-dioxide partial-pressure (T_CPCO₂) can be reliably measured and may be of clinical relevance in COPD. Changes in T_CPCO₂ and exercise-induced hypercapnia (EIH) during six-minute walk test (6MWT) need further investigation. We aimed (1) to define patterns of T_CPCO₂ trends during 6MWT and (2) to study determinants of CO2-retention and EIH.

METHODS

Sixty-two COPD patients (age: 63±8years, FEV1: 33±10%pred.) were recruited and T_CPCO2 was recorded by SenTec digital-monitoring-system during 6MWT.

RESULTS

Half of patients (50%) exhibited CO₂-retention (T_CPCO₂[Δ]>4mmHg); 26% preserved and 24% reduced T_CPCO₂. Nineteen (31%) patients presented EIH (T_CPCO₂>45mmHg). EIH was associated to higher baseline-P_CCO₂, worse FEV1, lower inspiratory-pressures, underweight/normal BMI, and pre-walk dyspnea. Stronger determinants of CO₂-retention were FEV1 and pre-walk dyspnea, whereas baseline-P_CCO₂ and pre-walk dyspnea better predict EIH.

CONCLUSIONS

PCO₂ response to 6MWT is highly heterogeneous; however, very low FEV1 and elevated baseline-P_CCO₂ together with pre-walk dyspnea increase the risk for CO₂-retention and EIH. Overweight-BMI seems to carry a protective effect against EIH in very severe COPD.

Lung Volume Reduction Surgery following Single-Lung Transplantation

Although single-lung transplantation is an established therapy for respiratory failure secondary to emphysema, hyperinflation of the native lung with concomitant compression of the transplanted lung is emerging as a cause of morbidity. In non-transplant emphysematous patients with hyperinflated lungs, pneumectomy was found to improve pulmonary function and quality of life. We report our experience on 5 single-lung transplant recipients with emphysema who underwent lung volume reduction surgery (pneumectomy, bullectomy, or anatomic resection) following transplantation. There were no perioperative deaths. Three patients underwent lung volume reduction because of a progressive symptomatic decline in pulmonary function that was thought to be secondary to hyperinflation of the native lung. Two of these patients had a sustained improvement in lung function and functional status over several years. Two other patients underwent lung volume reduction for removal of suspicious pulmonary nodules in the native lung. Both patients had a subsequent improvement in forced expiratory volume in one second. In our experience, lung volume reduction surgery after single-lung transplantation in emphysematous patients was a safe means of providing long-term improvement in pulmonary function.

Predicting the Response to Lung Volume Reduction Surgery Using Scintigraphy

This study was conducted to evaluate the use of quantitative scintigraphy with a newly designed marker to assess and predict the efficacy of lung volume reduction surgery in treating emphysema. In a series of 50 patients with severe emphysema who underwent the operation, ventilation/perfusion scintigraphy was performed and 2 markers of area ratio and lung uniformity were measured before and 6 months after surgery. The markers were correlated with the results of pulmonary function tests. The histopathological subtype of emphysema was also determined in the resected specimen and related to improvement in the markers. The markers were closely related to improvement in forced expiratory volume in 1 second, with the highest correlation being the marker lung uniformity measured by perfusion scintigraphy. Improvement in this marker was significantly greater in centrilobular than in panlobular emphysema. This quantitative method of scintigraphy could provide an excellent reflection of surgical efficacy as well as predict the surgical outcome. Additionally, it provides a mechanistic explanation for the differential improvement between the histopathological subtypes of emphysema following surgery.

Critical Care of the Lung Volume Reduction Surgery Patient

Lung volume reduction surgery (LVRS) offers the potential to improve lung function, exercise tolerance, and quality of life for patients with advanced emphysema. At present, the specific role of this procedure in the treatment of advanced emphysema is a subject of ongoing investigation. LVRS is most commonly performed bilaterally via either median sternotomy or video thoracoscopic approach with resection of the most severely affected lung tissue to reduce the overall lung volume by 20–30%. This results in improvements in lung elastic recoil, airway conductance, chest wall, and diaphragmatic function leading to greater inspiratory and expiratory airflow, decreased hyperinflation, and improved exercise tolerance. The greatest improvement after LVRS occurs within 3–6 months after surgery. In the perioperative period, however, lung function may be compromised by surgical incisions, pain, chest tubes, retained secretions, pneumonia, and parenchymal injury associated with resection. The risks of LVRS are not insignificant, with reported mortality prior to hospital discharge ranging from 2.5 to 14%. Pulmonary complications may include respiratory failure, persistent air leaks, pneumonia, tracheobronchitis, retained secretions, atelectasis, pneumothorax, bleeding, and sternal wound infections or dehiscence. Cardiac and gastrointestinal complications are the most common extrathoracic causes of perioperative morbidity after LVRS. Although many patients have an uneventful postoperative course, patients who experience complications frequently require prolonged mechanical ventilation and intensive care. Critical care practitioners must therefore be familiar with LVRS, its potential complications, and the ICU management of LVRS patients.

Non-pharmacological treatments for COPD

Chronic obstructive pulmonary disease (COPD) affects roughly 10% of the global population and is growing in prevalence annually. COPD is characterized by progressive non-reversible narrowing of airways mainly due to cigarette smoking. Therapeutic interventions aimed at altering this progressive disease course can largely be grouped into pharmacological or non-pharmacological therapies. The focus of this paper is on the non-pharmacological aspects of COPD management, reviewing the current literature to provide an evidence-based management approach. Non-pharmacological therapies reviewed in this article include the implementation of comprehensive care models utilizing a coordinated multidisciplinary team, tele-monitoring and patient-centred approach to optimize COPD care and improve compliance. Preventing progression of COPD via smoking cessation remains of paramount importance, and newer therapeutic options including electronic cigarettes show promise in small studies as cessation aids. COPD has systemic manifestations that can be ameliorated with the enrollment in pulmonary rehabilitation programmes, which focus on exercise endurance to improve dyspnoea and quality of life. Advanced therapeutics for COPD includes lung volume reduction surgery for a pre-specified cohort and minimally invasive bronchoscopic valves that in recent reviews show promise. Lastly, patients on maximal COPD therapy with progressive disease can be referred for lung transplantation; however, this often requires a highly selected and motivated patient and care team. Survival rates for lung transplantation are improving; thus, this procedure remains a viable option as more expertise and experience are gained.

Effective Bronchoscopic Lung Volume Reduction Accelerates Exercise Oxygen Uptake Kinetics in Emphysema

BACKGROUND

The impact of bronchoscopic lung volume reduction (BLVR) on physiologic responses to exercise in patients with advanced emphysema remains incompletely understood. We hypothesized that effective BLVR (e-BLVR), defined as a reduction in residual volume > 350 mL, would improve cardiovascular responses to exercise and accelerate oxygen uptake (Vo₂) kinetics.

METHODS

Thirty-one patients (FEV1, 36% ± 9% predicted; residual volume, 219% ± 57% predicted) underwent a constant intensity exercise test at 70% peak work rate to the limit of tolerance before and after treatment bronchoscopy (n = 24) or sham bronchoscopy (n = 7). Physiologic responses in patients who had e-BLVR (n = 16) were compared with control subjects (ineffective BLVR or sham bronchoscopy; n = 15).

RESULTS

e-BLVR reduced residual volume (-1.1 ± 0.5 L, P = .001), improved lung diffusing capacity by 12% ± 13% (P = .001), and increased exercise tolerance by 181 ± 214 s (P = .004). Vo₂ kinetics were accelerated in the e-BLVR group but remained unchanged in control subjects (Δ mean response time, -20% ± 29% vs 1% ± 25%, P = .04). Acceleration of Vo₂ kinetics was associated with reductions in heart rate and oxygen pulse response half-times by 8% (84 ± 14 to 76 ± 15 s, P = .04) and 20% (49 ± 16 to 34 ± 16 s, P = .01), respectively. There were also increases in heart rate and oxygen pulse amplitudes during the cardiodynamic phase post e-BLVR. Faster Vo₂ kinetics in the e-BLVR group were significantly correlated with reductions in residual volume (r = 0.66, P = .005) and improvements in inspiratory reserve volume (r = 0.56, P = .024) and exercise tolerance (r = 0.63, P = .008).

CONCLUSIONS

Lung deflation induced by e-BLVR accelerated exercise Vo₂ kinetics in patients with emphysema. This beneficial effect appears to be related mechanistically to an enhanced cardiovascular response to exercise, which may contribute to improved functional capacity.

Lung Volume Reduction Surgery and Improvement of Endothelial Function and Blood Pressure in Patients with Chronic Obstructive Pulmonary Disease. A Randomized Controlled Trial

RATIONALE

Cardiovascular disease is a major cause of morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD). Preliminary studies have shown that both airflow obstruction and systemic inflammation may contribute to endothelial dysfunction in COPD. Lung volume reduction surgery (LVRS) is a treatment option in selected patients with COPD with emphysema that improves breathing mechanics and lung function.

OBJECTIVES

To determine the effect of LVRS on endothelial function and systemic inflammation.

METHODS

We conducted a randomized controlled trial in 30 patients scheduled for LVRS. In the intervention group, immediate LVRS was performed after baseline evaluation followed by reassessment 3 months later. In the control group, reassessment followed 3 months after baseline evaluation, and thereafter LVRS was performed.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measures were the treatment effect on endothelial function and systemic inflammation. In the LVRS group 14 patients completed the trial and 13 in the control group. LVRS led to a relative reduction in mean (SD) residual volume/total lung capacity of -12% (12%) and an increase in FEV1 of 29% (27%). Flow-mediated dilatation of the brachial artery increased in the intervention group as compared with the control group (+2.9%; 95% confidence interval, +2.1 to +3.6%; P < 0.001), whereas there was no significant change in systemic inflammation. A significant treatment effect on mean blood pressure was observed (-9.0 mm Hg; 95% confidence interval, -17.5 to -0.5; P = 0.039).

CONCLUSIONS

Endothelial function and blood pressure are improved 3 months after LVRS in patients with severe COPD and emphysema. LVRS may therefore have beneficial effects on cardiovascular outcomes. Clinical trial registered with www.clinicaltrials.gov (NCT 01020344).