Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC, 3199, Australia.
Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Vic, Australia.
Respir Res. 2019 Jul 16;20(1):157. doi: 10.1186/s12931-019-1132-9.
The purpose of this study was to use CT scanning with computational fluid dynamics to evaluate the mechanisms by which Bronchial Thermoplasty (BT) improves asthmatic symptoms.
The study was conducted in a university teaching hospital, experienced in performing BT. Imaging studies were performed before, and after, BT of the left lung, and prior to treatment of the right lung, which therefore acted as a control. On each occasion, two high-resolution CT scans were performed, one at full inspiration (TLC) and the other at Functional Residual Capacity (FRC). The study protocol was offered to 10 patients, all of whom met the definition of severe asthma, despite high dose inhaled corticosteroids and dual long acting bronchodilators.
Significant increases in airway luminal volume were observed on the treated side, compared with control, at both full inspiration (by 27%) and at FRC (by 17%). The ratio of distal airway volume to lung volume significantly increased on the treated side. The change in airway volume with inspiration from FRC increased by 48% on the treated side compared to 5% in the control lung, suggesting treatment increased airway distensibility. No effect was observed on airway wall thickness, nor air trapping. There was a trend towards correlation between the improvement in airway volume at TLC and improvement in symptoms.
This study demonstrates that BT increases the luminal airway volume on the treated side compared to the control lung. We suggest that this is an important link between the airway smooth muscle atrophy demonstrated pathologically, and the improvement in symptoms observed clinically.
本研究旨在通过 CT 扫描和计算流体动力学来评估支气管热成形术（BT）改善哮喘症状的机制。
该研究在一家大学教学医院进行，该医院在进行 BT 方面经验丰富。在 BT 治疗左肺之前和之后，以及在治疗右肺之前，进行了影像学研究，右肺作为对照。在每次检查中，都进行了两次高分辨率 CT 扫描，一次在完全吸气（TLC）时，另一次在功能残气量（FRC）时。该研究方案提供给 10 名患者，所有患者均符合严重哮喘的定义，尽管接受了高剂量吸入皮质类固醇和双重长效支气管扩张剂治疗。
与对照侧相比，在治疗侧的完全吸气（增加 27%）和 FRC（增加 17%）时，气道管腔容积明显增加。远端气道容积与肺容积的比值在治疗侧显著增加。与对照肺相比，治疗侧的气道容积随 FRC 吸气的变化增加了 48%，这表明治疗增加了气道的可扩展性。气道壁厚度和空气滞留均无变化。气道容积在 TLC 上的改善与症状的改善之间存在相关性的趋势。
本研究表明，与对照肺相比，BT 增加了治疗侧的气道管腔容积。我们认为，这是病理上观察到的气道平滑肌萎缩与临床上观察到的症状改善之间的重要联系。
