Abstract
More than one mechanism may cause early and transient opacities in non-BT-treated lung zones http://ow.ly/3nfB30gzEpS
From the authors:
We read with great interest the correspondence by J.N.S. d'Hooghe and colleagues focusing on the pathophysiology of early transient radiological abnormalities following bronchial thermoplasty (BT). In line with our previous report [1], they have reported transient radiological opacities in all treated lobes of 12 BT-treated patients and in an adjacent untreated lobe in 31% of cases [2].
Atelectasis observed in this study directly after BT was of lesser magnitude than that we have previously reported. This discrepancy may be related to the severity of the lobe volume loss taken into account. Indeed, we considered any lobe volume loss, including mild aerated lobar collapse manifesting solely as displacement of interlobar fissures, whereas J.N.S. d'Hooghe and colleagues might have only considered partly aerated lobe atelectasis.
The authors propose that endobronchial blood, secretions or mucus moving from the BT-treated upper lobes down to the lower lobes may be a novel explanation for the observed opacities in BT-untreated lobes. We agree with this hypothesis that is supported by their observations showing a higher score of endoscopic mucosal injury in patients with opacities in distal areas of the untreated lobes, as compared to cases without opacities. We did not perform any endobronchial mucosal injury scoring at the time of BT and, therefore, comparisons cannot be performed on this particular issue. However, we found opacities of nondependent lung zones in six out of 12 untreated lobes (middle lobe (n=5) and culmen (n=1)). Therefore, the hypothesis raised by J.N.S. d'Hooghe and colleagues seems unlikely to explain all untreated lobe opacities found in our study. In addition, the possibility that endobronchial secretions or mucus cause parenchymal ground-glass opacities appears questionable. Rather, we believe that this event may promote bronchial and bronchiolar obstruction, with subsequent atelectasis or centrilobular opacities.
J.N.S. d'Hooghe and colleagues also question our hypothesis that heat shock diffusion along the bronchial tree may explain such untreated-lobe opacities. Pretolani and co-workers [3, 4] have demonstrated histopathological effects of BT in untreated middle lung lobes, including in the airway smooth muscle (ASM) area and ASM-related nerves. These findings support the hypothesis that the effect of BT extends to nondirectly treated zones. Whether this would lead to parenchymal opacities remains unknown.
Finally, we agree with J.N.S. d'Hooghe and colleagues that more than one mechanism may cause early and transient opacities in non-BT-treated zones.
Disclosures
Supplementary Material
M. Aubier ERJ-02067-2017_Aubier
P. Chanez ERJ-02067-2017_Chanez
M-P. Debray ERJ-02067-2017_Debray
M-C. Dombret ERJ-02067-2017_Dombret
A. Khalil ERJ-02067-2017_Khalil
C. Taillé ERJ-02067-2017_Taille
Footnotes
Conflict of interest: Disclosures can be found alongside this article at erj.ersjournals.com
- Received October 8, 2017.
- Accepted October 9, 2017.
- Copyright ©ERS 2017