Help Me, I Need Air: Patient Satisfaction after Endobronchial Valve Placement for Emphysema

Chronic obstructive pulmonary disease (COPD) is defined as a disease state characterized by airflow limitation that is not fully reversible. As we are aware, the main symptom of COPD is dyspnea or breathlessness. We are all too familiar with the patient with severe COPD whose quality of life is significantly degraded by their breathlessness and their frustration with their abilities to do important activities in their lives because of dyspnea and decreased exercise tolerance despite medical therapy.

The causes of dyspnea and decreased exercise capacity in COPD are multiple and complex and include airway obstruction with expiratory flow limitation, static and dynamic hyperinflation, intrinsic positive end-expiratory pressure (PEEP_i), increased respiratory muscle load, decreased respiratory muscle capacity, changes in neural respiratory drive with efferent–afferent receptor mismatch, pulmonary vascular changes, and peripheral muscle changes (1). Of these causes, hyperinflation, particularly dynamic hyperinflation, plays a central role in patients with severe emphysema with a poor quality of life because of breathlessness and inability to do activities.

Lung hyperinflation is defined as an abnormal increase in the amount of air at the tidal expiration, that is, end-expiratory lung volume (EELV) or functional residual capacity (FRC) (2). With destruction of lung parenchyma in emphysema, there is damage to the elastic fibers of the lung, leading to decreased lung elastic recoil pressure with unchanged chest wall compliance. Thus, EELV or FRC will occur at a higher lung volume (3). In addition, in the dependent lung regions, there is small airway closure and extreme expiratory flow limitation at low lung volumes, resulting in air-trapping and an increase in the residual volume (RV) (4). Both mechanisms increase total lung capacity and produce static hyperinflation. Dynamic hyperinflation, as the name implies, is a variable increase in lung volume above EELV or FRC owing to dynamic forces. In general, dynamic hyperinflation results from a mismatch of the expiratory time constant of the lung and time between consecutive breaths (4). The expiratory time constant for lung emptying for patients with severe emphysema is increased because of decreased lung elastic recoil pressure and increased airway resistance (3, 5). During activity, the expiratory time needed for exhalation becomes insufficient as the respiratory rate increases, and thus EELV increases, resulting in dynamic hyperinflation.

A number of negative consequences results from lung hyperinflation. There is an increase in the work of breathing. In addition to the lung elastic recoil, an increase in the inspiratory elastic load results from EELV moving above the relaxation volume of the chest wall with significant hyperinflation such that at EELV the chest wall will recoil inward (1). When dynamic hyperinflation occurs, the expiratory alveolar pressure remains positive throughout expiration until the next breath, PEEP_i. The inspiratory muscles must overcome PEEP_i before negative pressure can be generated to produce inspiratory flow (4). Lastly, there is decreased capacity of the inspiratory muscles to generate negative intrathoracic pressure in the presence of hyperinflation owing to muscle sarcomere shortening, flattening of the diaphragm, and reduced zone of apposition of the diaphragm (1, 4).

Treatments that decrease hyperinflation should improve breathlessness and exercise capacity in patients with severe emphysema. Lung volume reduction surgery (LVRS) has been shown to decrease total lung capacity and RV with improvements in forced expiratory volume in 1 second (FEV₁), forced vital capacity, and inspiratory capacity (6). Global inspiratory muscle strength has been observed to increase after LVRS, as has maximal exercise capacity (6). In NETT (National Emphysema Treatment Trial), patients undergoing LVRS compared with medical therapy had greater improvements in exercise capacity, 6-minute walk distance, severity of dyspnea, and disease-specific quality of life (7). To obviate the morbidity and mortality issues with LVRS, various bronchoscopic modalities to produce bronchoscopic lung volume reduction (BLVR) have been studied. Of these, bronchoscopically implanted one-way valves have been the most successful and have been able to obtain U.S. Food and Drug Administration approval. One of these valves, the Zephyr valve (Pulmonx Corporation) has been shown to improve FEV₁, RV, 6-minute walk distance, and quality of life as measured by the St. George's Respiratory Questionnaire (8).

Although studies evaluating BLVR have reported on patient-centered outcomes such as dyspnea, walking distance, and disease-specific quality of life, patient-reported outcomes such as treatment satisfaction and improvements in patient pretreatment individual goals have not been evaluated. In this issue of AnnalsATS, Hartman and colleagues (pp. 68–74) provide information about these important questions (9). Their aims were to investigate patient satisfaction level 1 year after treatment and patient-specific goals before and 1 year after endobronchial valve (EBV) placement. Patients with severe emphysema who underwent EBV treatment as part of regular care in the authors’ registry before January 1, 2019, and planned for a 1-year follow-up visit were included in the study. Patients were asked to complete a self-designed patient satisfaction questionnaire, which consisted of five questions, at the 1-year follow-up after EBV treatment. Patients who did not visit the hospital for various reasons, for example, because of the need to remove the valves, were also asked to complete this questionnaire. Patient-specific goals were measured by the Dutch Patient-Specific-Complaints (PSC) questionnaire, which is similar to a patient-specific functional scale. Patients reported their personal three most important post-treatment desired goals and to score on a numeric rating scale (scale 0–10) the level of disability per goal, before treatment. Patients were then asked to score the scale for the same self-reported goals at baseline at 1 year after treatment.

In total, 134 patients underwent EBV treatment. Ninety-one (97%) of the 94 patients who visited the investigators after 1 year completed the patient satisfaction questionnaire. The questionnaire was also sent to 27 patients who were lost to follow-up, and 18 (67%) of these patients also filled out the questionnaire. A total of 88 patients filled out the PSC at baseline and 1 year after EBV treatment. Seventy-five percent on patients were satisfied or very satisfied with treatment, whereas only 11% were unsatisfied or very unsatisfied with treatment. Fifty-three percent were satisfied or very satisfied with reduction in symptoms, whereas 25% were unsatisfied or very unsatisfied with reduction in symptoms. The PSC-sum score significantly improved 1 year after EBV treatment. In addition, the five most frequently reported goals also significantly improved after 1 year. When adjusting for patients lost to follow-up, overall, 91% of patients would recommend the treatment to other patients, whereas only 2% of patients would not recommend the treatment to other patients. Improvements in the PSC-sum scores and higher level of patient satisfaction were associated with larger improvements in FEV₁, RV, exercise capacity, dyspnea severity, and quality-of-life measures.

There are some limitations to this study. First, the results could be biased by better satisfaction and goal improvements in those who returned for the 1-year visit and missing data from those who did not. The authors acknowledge this potential bias and attempt to adjust for it in their statistical methods, yet such a bias is possible. The second is that although there was an improvement in the numerical rated score of the PSC, there was not a meaningful important difference value for this questionnaire to provide further clinical context.

This study by Hartman and colleagues provides new and insightful information about BLVR using EBVs. Previous studies have demonstrated improvements in disease-specific quality of life, but this study generates important data about the patient’s perception’s and experience with the procedure. Overall, the patient-reported outcomes in this study are quite positive. However, only 75% of patients were satisfied or very satisfied with the treatment, and only 53% were satisfied or very satisfied with reduction in symptoms after treatment. On an analog scale with a score range of 1–5, the mean score for the question “did the result of your treatment fulfill your expectations” was 3.3. I am in agreement with the authors that these results suggest that more discussions about the expected benefits of BLVR and setting reasonable expectations for outcomes are sorely needed before the procedure and need to be part of the shared decision-making process. What I find interesting about this study is that despite the observed levels of satisfaction and fulfillment, 91% of patients who underwent EBV treatment would recommend it to other patients. Whether it is because these patients overall felt they had more benefit than satisfaction scores represented, or they feel patients with severe emphysema have no other good treatment option and it is worth a try no matter what, is unclear to me. Given my personal experience, I suspect that the latter is a strong component of that 91% yes response to “would recommend treatment to other patients” and, again, argues for having an honest and open discussion about the benefits and outcomes for the procedure so that patients have the proper expectations and are not overly disappointed by their results.