What is the key question?

• Investigate the effects of bronchial thermoplasty (BT) on airway smooth muscle (ASM) in asthma and predictors for response to treatment.

What is the bottom line?

• This was a multicentre randomized-control trial which enrolled 40 patients to either upfront BT or those having delayed BT (6 months later), and compared symptom scores, asthma exacerbations, lung function testing and histology.
• Primary endpoint found a significant 53% reduction in airway smooth muscle mass at 6 months.
• The right middle lobe, not usually treated with BT, was found to also have significant reductions of ASM of 3%. This reduction was histologically detected only in proximal segmental biopsies.
• Asthma control questionnaires and asthma quality of life questionnaires scores were significantly improved in the BT arm. Asthma exacerbations were significantly reduced (1.5 events per half-year compared to 0). Airway reversibility measures were also significantly reduced.
• Positive correlation was found between symptom score improvements post-treatment and elevated eosinophil or IgE counts.

Why read on?

• The authors provide details on the negative associations in the trial, and also an interesting discussion about how bronchial thermoplasty might produce some its clinical and histological benefits, particularly in areas not treated during the procedure.