Impact of Bronchial Thermoplasty on the FeNO Levels in Asthmatic Patients

Abstract

PURPOSE: Asthma affects 23 million American adults. It is characterized by intermittent airway hyper-responsiveness and inflammation which may be triggered by infection, allergens, stress, etc. Bronchial thermoplasty (BT) is a treatment for patients with severe asthma who continue to be symptomatic despite maximal medical treatment. Though randomized clinical trials of BT have shown an improvement in quality of life, they did not show a reduction in commonly followed markers to evaluate asthma control. Fractional excretion of nitric oxide (FeNO) is a new biomarker that is used to guide steroid therapy in asthmatics. The effect of BT on FeNO levels has not been reported. We hypothesized that BT may have an effect on FeNO levels. METHODS: We performed a retrospective review of our patients who underwent BT to assess its impact on FeNO levels. A change of 10ppb in FeNO level was considered significant. RESULTS: Eight out of eleven patients had pre and post BT FeNO levels. There was no statistically significant change in pre and post-BT FeNO levels. However, three out of four patients who had high baseline FeNO levels (greater than 25 ppb) showed a significant decrease in post-BT FeNO levels (p=0.03). The fourth patient had a high FeNO level attributed to an asthma exacerbation due to a URI at the time of post-BT FeNO measurement. Furthermore, all four patients with high baseline FENO levels showed a trend towards improved FVC post-BT (18±6% change in predicted values) compared to patients who had normal FeNO (8.25±1.37%) (p=0.08). Other interesting findings were that 70% of patients who were on chronic oral steroids pre-BT, regardless of their FENO levels, were weaned off oral steroids six weeks post-BT. CONCLUSIONS: BT reduced FeNO levels and increased FVC in patients who have high baseline FeNO.