Utility of a thin bronchoscope in facilitating bronchial thermoplasty

Abstract

Background: A significant correlation has been previously demonstrated between the quantum of radiofrequency treatment delivered at bronchial thermoplasty and the degree of improvement in an asthmatic patient’s symptoms. The standard bronchoscope used for bronchial thermoplasty has an outer diameter of 4.8 mm at the distal tip. Thinner bronchoscopes are now available with the same internal channel size (2.0 mm). This study assesses whether using a thinner bronchoscope facilitates bronchial thermoplasty by increasing the radiofrequency activations delivered. Patients and methods: This was a sequential study in a single center, conducted in 27 patients with very severe asthma. The first 12 patients (Group 1) underwent bronchial thermoplasty using the standard bronchoscope, Olympus BF-Q190. In the next group of eight patients (Group 2), the standard bronchoscope was used for all procedures except the left upper lobe, while the left upper lobe was treated with a smaller bronchoscope, Olympus BF-P190, with an outer diameter of 4.2 mm. In the last group of seven patients (Group 3), the smaller bronchoscope was used for every lobe. The quantum of radiofrequency treatment was measured by activations delivered to each lung lobe in each patient, and patient groups were compared by ANOVA. Results: In this group of 27 patients, the mean age was 56.5±12.9 years, the mean Asthma Control Questionnaire-5 item version score was 3.2±1.0 and the mean FEV1% predicted was 55.2±15.7. Bronchial thermoplasty treatment resulted in significant improvements in predicted Asthma Control Questionnaire-5 item version score (to 1.8±1.3, P<0.005), salbutamol rescue usage and oral corticosteroid requiring exacerbations, with no significant change in lung function. Use of the smaller bronchoscope resulted in greater radiofrequency treatment (total activations Group 1: 155±21, Group 2: 176±46, Group 3: 213±37; P<0.01). There were no significant differences in efficacy or safety outcomes among groups. Conclusion: Using a thinner bronchoscope facilitates access to the bronchial tree and increases the radiofrequency treatment delivered at bronchial thermoplasty.