Bronchial Thermoplasty in the Treatment of Severe Asthma

Abstract

Asthma is a chronic inflammatory airway disease with several distinct phenotypes, characterized by different immunopathological pathways, clinical presentation, severity of the disease, and response to treatment. The phenotypes of asthma include eosinophilic, neutrophilic, mixed granulocytic, and paucigranulocytic asthma. Approximately 3.6-10% of patients with asthma have severe refractory disease, which is unresponsive to high dose inhaled corticosteroids (ICS), and long-acting β2-agonists (LABA). Most patients with eosinophilic asthma are responsive to corticosteroids, and interleukintargeted biologics, whereas, patients from other phenotypes, such as neutrophillic and paucigranullocytic asthma are resistant to treatment with ICS and biotherapeutics. The hallmark of severe refractory asthma is airway hyperresponsiveness, and remodeling. Histopathologically, patients with severe asthma have airway smooth muscle (ASM) hyperplasia and hypertrophy; subepithelial basement membrane thickening and fibrosis; all which contribute to fixed airflow limitation. Severe refractory asthma is very difficult to treat pharmacologically. It requires innovative therapies, such as bronchial thermoplasty which reduces the hypertrophied ASM mass and relieves the AHR, and broncoconstriction. Bronchial thermoplasty has been shown to improve asthma control, reduce severe exacerbations, hospitalizations, emergency room visits, and improve the quality of life, which persist up to 5 years following the procedure