Interventional Pulmonology for Asthma and Emphysema: Bronchial Thermoplasty and Bronchoscopic Lung Volume Reduction

Abstract

Emphysema and asthma are responsible for economic and social burden. Altering the natural course of these diseases is a field of intense research. The National Emphysema Treatment Trial showed that lung volume reduction surgery (LVRS) could significantly reduce both morbidity and mortality in properly selected patients. LVRS is seldom performed, however, due to the high morbidity associated with the surgery. Numerous bronchoscopic interventions have been introduced with the goal of providing the clinical benefits of LVRS without the surgical complications. Thus far, these modalities have not produced the results once hoped. However, through active modification of both technique and patient selection, the role of minimally invasive modalities in the treatment of emphysema continues to evolve. Bronchial thermoplasty (BT) is a method of delivering controlled heat to airway mucosa with the goal of reducing airway smooth muscle mass and hence bronchoconstriction. In patients suffering from asthma who cannot achieve control with standard medical care, BT has been shown to be safe and improves symptoms, with long lasting benefit. BT does not seem to affect traditional markers of asthma severity such as forced expiratory volume in 1 second and questions remain regarding proper patient selection for this therapy and its true physiologic effects. This article is a review of bronchoscopic modalities for emphysema and asthma.

Asthma

“…Bronchial thermoplasty, delivered by the Alair ™ System, is a treatment for severe asthma that was approved by the US FDA in 2010. This treatment involves the delivery of controlled, therapeutic radio frequency energy to the airway wall to heat the tissue and thereby reduce the amount of smooth muscle in the airway wall 226 . This procedure causes epithelial injury followed by regeneration of the epithelium, blood vessels, mucosa and nerves but not airway smooth muscle 227,228 .…”

Recommendations for the use of bronchial thermoplasty in the management of severe asthma

“…The latter approach is justified when interpreting AQLQ scores, which reflect within-group differences better than between-group differences. [11] Thirdly, the placebo effect is well recognised in asthma trials, and the AQLQ improvement in the sham group was probably due to more meticulous and protocol-driven asthma care during the trial, as well as standardisation of care before recruitment. Given this consideration, the AIR2 study should ideally have incorporated a longer run-in period, and in retrospect, chosen asthma exacerbation or ER visits as an a priori primary outcome.…”

“…It is performed as an outpatient hospital procedure over three treatment sessions by a trained pulmonologist under conscious sedation, after which the patient returns to the primary referring physician for long-term asthma management. The BT procedure itself has been outlined and reviewed in detail elsewhere [9][10][11] and is summarised in Fig. 1.…”

Recent trends in management of bronchial asthma

“…Bronchial thermoplasty, delivered by the Alair™ System, is a treatment for severe asthma that was approved by the US FDA in 2010 (Figure 6). This treatment involves the delivery of controlled, therapeutic radiofrequency energy to the airway wall to heat the tissue and thereby reduce the amount of smooth muscle in the airway wall (Miller & Murgu, 2014). This procedure causes epithelial injury followed by regeneration of the epithelium, blood vessels, mucosa and nerves but not airway smooth muscle (Castro et al, 2015).…”