Bronchial Thermoplasty in Severe Uncontrolled Asthma With Different Phenotypes

Endobronchial treatment of severe asthma and severe emphysema with hyperinflation

PURPOSE OF REVIEW

The field of interventional pulmonology has ushered in a wave of innovations for individuals with obstructive airways disease in whom established medical therapies have failed. Leading the charge are bronchial thermoplasty for severe refractory asthma and uni-directional valves for severe emphysema with hyperinflation: both have received regulatory approvals in the United Kingdom and United States. With the commissioning of these novel treatments comes new challenges relating to implementation, positioning within therapeutic algorithms, honing of patient selection, and establishing long-term safety and benefits beyond 5 years.

RECENT FINDINGS

This review summarises the evidence for their safety and efficacy, predictors of therapeutic response, mechanism(s) of action and emerging data supporting the durability of outcomes out to at least ten years.

SUMMARY

It is anticipated the experience of treating increasing numbers of patients, the adoption of international registries, and ongoing research evaluations will serve to optimise these therapies for future generations of patients.

Predicting the Response to Bronchial Thermoplasty

BACKGROUND

Although it is established that not all patients respond to bronchial thermoplasty (BT), the factors that predict response/nonresponse are largely unknown.

OBJECTIVES

To identify baseline factors that predict clinical response.

METHODS

The records of 77 consecutive patients entered into the Australian Bronchial Thermoplasty Registry were examined for baseline clinical characteristics, and outcomes measured at 6 and 12 months after BT, such as change in the Asthma Control Questionnaire (ACQ) score, exacerbation frequency, the requirement for short-acting beta-2 agonist (SABA) medication and oral corticosteroids, and improvement in spirometry.

RESULTS

This was a cohort of patients with severe asthma: aged 57.7 ± 11.4 years, 57.1% females, 53.2% of patients taking maintenance oral steroids, 43% having been treated with an mAb, mean FEV₁ of 55.8% ± 19.8% predicted.

RESULTS

BT resulted in an improvement in the ACQ score from 3.2 ± 1.0 at baseline to 1.6 ± 1.1 at 6 months (P < .001). Exacerbation frequency in the previous 6 months reduced from 3.7 ± 3.3 to 0.7 ± 1.2 (P < .001). SABA requirement reduced from 9.3 ± 7.1 puffs/d to 3.5 ± 6.0 (P < .001), and 48.8% of patients were weaned completely off oral steroids. A significant improvement in FEV₁ was observed. Using multiple linear regression models, baseline ACQ score strongly predicted improvement in ACQ score (P < .001). Patients with an exacerbation frequency greater than twice in the previous 6 months showed the greatest reduction in exacerbations (-5.3 ± 2.8; P < .001). Patients using more than 10 puffs/d of SABA experienced the greatest reduction in SABA requirement (-12.4 ± 10.5 puffs, P < .001).

CONCLUSIONS

The most severely afflicted patients had the greatest improvements in ACQ score, exacerbation frequency, and medication requirement.

Bronchial thermoplasty as a treatment for severe asthma: controversies, progress and uncertainties

INTRODUCTION

Bronchial thermoplasty is a licensed non-pharmacological treatment for severe asthma. Area covered: This article considers evidence for the efficacy and safety of bronchial thermoplasty from clinical trials and observational studies in clinical practice. Its place in the management of severe asthma, predictors of response and mechanisms of action are reviewed. Expert commentary: Bronchial thermoplasty improves quality of life and reduces exacerbations in moderate to severe asthma. Morbidity from asthma is increased during treatment. Overall, patients treated in clinical practice have worse baseline characteristics and comparable clinical outcomes to trial data. Follow-up studies provide reassurance on long-term safety. Despite some progress, future research needs to investigate uncertainties about predictors of response, mechanism of action and place in management of asthma.