Chronic obstructive pulmonary disease (COPD) remains one of the most prevalent lung disorders in the world. The main driver of this disease, as proven by studies time and again, is the cumulative impact of years of cigarette smoking.
The destruction to the lungs is so obvious that any physician auscultating the chest of a patient with this condition would almost certainly be able to identify the disease, especially with the corroboration of smoking history. COPD is deeply unpleasant as patients contend with it day and night; some patients describe the sensation as similar to “drowning.”
In the lungs of people with AATD, airflow is profoundly limited, meaning patients lose the quiet equilibrium one feels when breathing in fresh air; they are, in a sense, perpetually gasping. In most cases, patients with COPD also have some issues with their heart, since the cardiac and pulmonary systems are closely intertwined. Studies indicate that patients with both COPD and cardiac failure have substantially poorer outcomes.
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At the end stage of COPD is severe emphysema; this is characterized by significant losses of terminal bronchioles and the collapse of airway patency. In patients with end-stage COPD, intrathoracic pressure is high and the pulmonary vasculature is compressed; this invariably leads to pulmonary hypertension. In addition, the abnormally high intrathoracic pressure obstructs normal venous return, causing a reduced cardiac output.
“Hyperinflation increases the work of breathing by pushing the tidal volume loop to the less compliant portion of the respiratory volume-pressure curve, so that patients must generate more pressure to breathe in or out,” Alshabani and colleagues wrote in the Cleveland Clinic Journal of Medicine.
Providing Relief From Symptoms
It is no exaggeration to say that patients with severe COPD are under extreme duress. So what can be done about it? Traditional drugs used to treat COPD, such as bronchodilators and anti-inflammatory medications, may no longer suffice. Extreme circumstances call for extreme measures, and one of the means for achieving symptomatic relief is lung volume reduction.
Lung volume reduction surgery has been around since the mid 1950s. Its main goal is to remove emphysematous lung in the hopes that some sense of normal pulmonary physiology can be restored. Despite advancements in surgical practice, the mortality rate for this procedure remains relatively high, between 4% to 17%.
Because this surgical procedure is so risky, there are stringent inclusion criteria to meet to be considered a candidate for this operation. The primary criterion is showing signs of severe emphysema; forced expiratory volume in 1 second (FEV1) must be less than 45% of predicted. In addition, individuals must have abstained from cigarette smoking for 6 months or more and have completed pulmonary rehabilitation.
“[This surgery] offers a means of restoring some normality to the intrathoracic mechanics and has been shown to compare favorably with standard of care in patients with severe emphysema and hyperinflation,” Garner and colleagues wrote in a letter to the editor published in the American Journal of Respiratory and Critical Care Medicine.
Treating Emphysema Driven by AATD
Alpha-1 antitrypsin deficiency (AATD) is a rare genetic disorder that can drive COPD, even in the absence of an extensive smoking history (however, cigarette smoking can accelerate lung function decline). Patients with AATD tend to become symptomatic in their 30s; in contrast, patients without AATD but with COPD tend to present in their 50s.
Read more about AATD etiology
“Emphysema in AATD typically presents as panlobular and predominantly in the lower lobes, in contrast to the centrilobular and apical smoking-induced emphysema,” Everaerts and colleagues wrote in a study published in Respiration.
The research team sought to understand the effects of bronchoscopic lung volume reduction using one-way endobronchial valves (EBVs) on the symptoms of patients with AATD and severe emphysema. They retrospectively analyzed the clinical data of all patients with a confirmed AATD diagnosis who underwent EBV treatment at the University Medical Center Groningen in the Netherlands between 2013 and 2021 (n=30).
They reported that “all response variables improved significantly after treatment.” For example, there was a median increase of 12% in the FEV1 and a median improvement of 62 minutes in the 6-minute walk distance test (6MWD). In terms of safety profile, a pneumothorax occurred in 10% of patients, and 10% of patients required revision bronchoscopy within 6 months.
“This study demonstrates that the EBV treatment is a feasible, effective, and . . . safe treatment option in selected patients with AATD,” the authors of the study concluded. “The functional outcome and quality of life were encouraging at 6 months and without safety concerns.”
Read more about AATD treatment
This study, as well as others, gives a generally favorable picture of the efficacy of lung volume reduction surgery in patients with severe emphysema. Nevertheless, more work needs to be done. For example, this study does not look at how lung volume reduction impacts COPD exacerbations, which are difficult to measure due to their sporadic nature. In addition, few studies explore the effect of lung volume reduction on the second half of the COPD equation: chronic bronchitis.
Nevertheless, because so few therapies are effective in end-stage COPD, the limited success of lung volume reduction should be lauded.
References
Garner JL, Shah PL. Bronchoscopic lung volume reduction: to the heart of the matter. Am J Respir Crit Care Med. 2022;206(6):655-656. doi:10.1164/rccm.202206-1026ED
Everaerts S, Hartman JE, Van Dijk M, Koster TD, Slebos DJ, Klooster K. Bronchoscopic lung volume reduction in patients with emphysema due to alpha-1 antitrypsin deficiency. Respiration. 2023;102(2):134-142. doi:10.1159/000528182
Alshabani K, Gildea TR, Machuzak M, Cicenia J, Hatipoğlu U. Bronchoscopic lung volume reduction with valves: what should the internist know? Cleve Clin J Med. 2020;87(5):278-287. doi:10.3949/ccjm.87a.19083
