Role of narrow band imaging in assessing bronchial mucosal hypervascularization in COVID-19 patients

Background: SARS-CoV-2 virus which targets the lung vasculature is supposed to affect both pulmonary and bronchial arteries. This study evaluated the tracheobronchial vascularization density observed with narrow band imaging (NBI) in patients hospitalized for COVID-19 pneumonia. To determine if the observed changes were specific of COVID-19 patients, the procedure was also performed in non-COVID-19 patients.

Methods: Thirty patients included in this monocentric, prospective study underwent videobronchoscopy using both white light and NBI: 10 with a COVID-19 infection, 10 with a non-COVID-19 pulmonary infection and 10 with a peripheral pulmonary nodule. The tracheobronchial vascular density observed through NBI was rated by two blinded pneumologists at three levels (carina, right main bronchus and left main bronchus).

Results: When compared to the two other groups, a significant increase of the tracheobronchial vascularization was found in COVID-19 patients. The median tracheobronchial vascularization global score obtained with NBI (out of 15 points) was: 10 [9 - 13] in the COVID-19 group, 5 [4 - 10] in the non-COVID-19 group (p < 0.001) and 6 in the Nodule group [4 - 9] (p = 0.002). Using a weighted Cohen's Kappa coefficient, we observed a good agreement between the two raters for the evaluation of the tracheobronchial vascularization score (κ = 0.75 [0.65-0.83]); p < 0.001).

Conclusion: Videobronchoscopy with NBI in COVID-19 patients showed diffuse changes in tracheobronchial vascularization. We suggest that such bronchial hypervascularisation with dilated vessels contributes, at least in part, to the intrapulmonary right to left shunt that characterized the COVID-19 related Acute Vascular Distress Syndrome (AVDS).