David Langton1, Wei Wang2, Francis Thien3, Virginia Plummer4. 1. Department of Thoracic Medicine, Frankston Hospital, Victoria, Australia; Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia. Electronic address: davidlangton@phcn.vic.gov.au. 2. Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia. 3. Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia; Department of Respiratory Medicine, Eastern Health, Vic, Australia. 4. Department of Thoracic Medicine, Frankston Hospital, Victoria, Australia; Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia.
Abstract
BACKGROUND: The most common adverse effect of bronchial thermoplasty (BT) is short-term aggravation of asthma immediately following the procedure. However, the magnitude and duration of this deterioration, and its predisposing factors are yet to be quantitated. This information will be particularly important as BT is extended to include more severely obstructed patients. METHODS: In this prospective, observational study of 20 consecutive patients with very severe asthma undergoing BT, post bronchodilator FEV1 was measured in the 30 min prior to surgery, and then 24 h following the 60 procedures. In half the patients, further spirometry was conducted on day 3 and day 7 post procedure. RESULTS: This study enrolled 12 males and 8 females, mean age 59.7 ± 12.8 years, with mean prebronchodilator FEV1 of 52.3 ± 15.2% predicted, mean forced expiratory ratio of 51.4 ± 12.6%, and mean improvement in FEV1 post salbutamol of 19.5 ± 15.3%. All patients were taking inhaled corticosteroids, mean beclomethasone equivalent dose 1950 ± 857 mcg, and 7 patients required maintenance oral corticosteroids for control of their asthma. Twenty four hours after BT, the mean deterioration in post bronchodilator FEV1 was 166 ± 237 mls (CI 102-224, p < 0.001) or 9.1 ± 15.2% of baseline. This deterioration was significantly greater after upper lobe procedures (p < 0.01, ANOVA repeated measures), where a mean fall in FEV1 of 17.1 ± 12.6% was observed. The change in FEV1 post procedure was significantly correlated with the number of radiofrequency activations applied, r = -0.376, p < 0.005. By multivariate analysis, the only factor other than activations predictive of the change in FEV1 was age, which was protective. When the lower lobes were treated, the postbronchodilator FEV1 had returned to baseline values by day 3, but patients took 7 days to recover after upper lobe treatments. Despite the severity of asthma in these patients, and the measured deterioration post treatment, there was only one instance of readmission in the 60 procedures. CONCLUSIONS: The deterioration in lung function after BT is transient and well tolerated, but is greatest after upper lobe treatment, and is significantly related to the number of radiofrequency activations applied.
BACKGROUND: The most common adverse effect of bronchial thermoplasty (BT) is short-term aggravation of asthma immediately following the procedure. However, the magnitude and duration of this deterioration, and its predisposing factors are yet to be quantitated. This information will be particularly important as BT is extended to include more severely obstructed patients. METHODS: In this prospective, observational study of 20 consecutive patients with very severe asthma undergoing BT, post bronchodilator FEV1 was measured in the 30 min prior to surgery, and then 24 h following the 60 procedures. In half the patients, further spirometry was conducted on day 3 and day 7 post procedure. RESULTS: This study enrolled 12 males and 8 females, mean age 59.7 ± 12.8 years, with mean prebronchodilator FEV1 of 52.3 ± 15.2% predicted, mean forced expiratory ratio of 51.4 ± 12.6%, and mean improvement in FEV1 post salbutamol of 19.5 ± 15.3%. All patients were taking inhaled corticosteroids, mean beclomethasone equivalent dose 1950 ± 857 mcg, and 7 patients required maintenance oral corticosteroids for control of their asthma. Twenty four hours after BT, the mean deterioration in post bronchodilator FEV1 was 166 ± 237 mls (CI 102-224, p < 0.001) or 9.1 ± 15.2% of baseline. This deterioration was significantly greater after upper lobe procedures (p < 0.01, ANOVA repeated measures), where a mean fall in FEV1 of 17.1 ± 12.6% was observed. The change in FEV1 post procedure was significantly correlated with the number of radiofrequency activations applied, r = -0.376, p < 0.005. By multivariate analysis, the only factor other than activations predictive of the change in FEV1 was age, which was protective. When the lower lobes were treated, the postbronchodilator FEV1 had returned to baseline values by day 3, but patients took 7 days to recover after upper lobe treatments. Despite the severity of asthma in these patients, and the measured deterioration post treatment, there was only one instance of readmission in the 60 procedures. CONCLUSIONS: The deterioration in lung function after BT is transient and well tolerated, but is greatest after upper lobe treatment, and is significantly related to the number of radiofrequency activations applied.