Bronchial thermoplasty in asthma: Scrutinizing the current evidence

Abstract

Objectives: Severe asthma accounts for 5-10% of all asthma cases and half of asthma-related costs in developed countries. Targeting smooth muscle hypertrophy and hyperplasia using bronchial thermoplasty (BT) represents a novel therapeutic approach to this disease. This review aims to critically examine and appraise the methodology and interpretation of individual clinical trials concerning the use of BT in severe asthma. It is not intended to be a systematic review or a meta-analysis. Methods: PubMed, Ovid MEDLINE, Ovid EMBASE, Google Scholar, and Scopus were searched until August, 31st 2015 for published clinical trials concerning the use of BT in asthma patients. Search titles included BT, severe asthma, BT in asthma, BT and severe asthma and effectiveness and safety of BT in asthma. Results: One published non-randomized, three randomized and three extension trials were identified. The methodology and results of each individual trial were subjected to careful examination and appraisal. A good safety profile of BT as a novel therapeutic approach of severe asthma has been confirmed in multiple clinical trials. However, there are still unanswered questions and concerns regarding the effectiveness of this procedure in severe asthma. The evidence concerning this effectiveness needs to be augmented by further well-designed sham controlled trials. Conclusion: Well-designed controlled trials using hard outcome measures such as asthma control, lung function and ability to withdraw/reduce steroid are desperately needed to confirm the effectiveness of BT in severe asthma cases. Consideration of asthma phenotypes when conducting such trials would be rewarding.