Monday, April 10, 2017
Effectiveness of bronchial thermoplasty in patients with severe refractory asthma: clinical and histopathological correlations
Asthma is a disease in which the airways of the lung become very sensitive to certain triggers, leading to spasms, in turn causing shortness of breath, coughing and wheezing. The ultimate cause of asthma is unclear, but it has been shown in previous studies that there is remodeling of the airways in severe asthma. Airway smooth muscle (ASM) increases, along with fibrosis, infiltration of new blood vessels, and growth of cells that line the airways. Recently, a procedure called bronchial thermoplasty (BT) has been developed, in which an endoscope is inserted into the airways. This endoscope then delivers a temperature-controlled radio frequency to the airway wall. In this month’s issue of JACI, Pretolani and colleagues look at bronchial thermoplasty and its effect on various clinical and histopathological findings (J Allergy Clin Immunol 2017; 139(4): 1176-1185).
In order to do this, they recruited 15 patients with severe uncontrolled asthma that did not respond to medications. They looked at the symptoms through the Asthma Control Test (ACT) and the Asthma Quality of Life Questionnaire (AQLQ), as well as breathing patterns via spirometry and biopsy samples. Bronchial thermoplasty was then performed. At 3 and 12 months, the clinical and airway effects were examined.
What they found is that asthma control and quality of life increased considerably. Exacerbations requiring oral steroids, emergency room visits, and hospitalizations were also decreased by approximately 90%. Biopsy samples from 3 months showed a decrease in ASM size, as well as nerve fibers and neuroendocrine cells.
Based on these results, Pretolani and colleagues conclude that bronchial thermoplasty is an option for severe, uncontrolled, treatment refractory asthma. Bronchial thermoplasty seems to affect the structure of airways, especially muscle size and nerve connections. Targeting these structures, through thermoplasty or other means may be an effective way to help control these difficult-to-control cases.