Complex modeling of the human lung has shown a likely explanation for how bronchial thermoplasty reduces health care needs and improves quality of life in patients with moderate to severe asthma.
The study found the observed benefits of bronchial thermoplasty could be explained by changes in whole-lung flow patterns, induced by structural changes in the treated airways.
Previously, it was thought that the small number of large airways treated during bronchial thermoplasty was insufficient to explain the observed benefits in what has been a controversial procedure.
The study used whole left lung specimens from non-asthma controls, non-respiratory deaths in people with asthma and confirmed asthma deaths, to create mathematically simulated lungs.
The research team was able to simulate lung structure and function and calculate airflow pre and post simulated bronchial thermoplasty.
The bronchial thermoplasty protocol was based on current clinical practice – treating the lower lobe bronchus, upper lobe bronchus, superior division bronchus and LB1-10 to effect a 75% reduction in airway smooth muscle.
They found that central airway structural changes trigger global flow redistribution toward more homogeneous and efficient flow patterns.
“It arises from the structural alteration of a small number of treated central airways only – no other mechanisms are required…,” they said.