HISTOLOGICAL FINDINGS IN TRANSBRONCHIAL CRYOBIOPSIES OBTAINED FROM PATIENTS AFTER COVID-19

Abstract

Background: Following severe acute respiratory syndrome coronavirus 2-induced pneumonia, some patients develop diffuse interstitial lung disease (DILD). However, no histological study has confirmed this alteration. This study describes the histological findings of transbronchial cryobiopsy (TBC) specimens obtained with single-use flexible bronchoscope (FB) and cryoprobe from these patients.

Methods: 1996 patients were referred to a specialized consultation for assessment for post-COVID-19 sequelae, and to date 757 patients have already been visited. TBC through FB was recommended when radiological alterations suggestive of DILD were observed and in addition there were clinical criteria, based on the Modified Medical Research Council Dyspnea Scale, or functional criteria (forced vital capacity and/or DLCO between 40-70% of theoretical value, or desaturation in 6MWT).

Results: 50 patients were included. There were no significant complications in any procedure. A histological diagnosis was obtained for all patients, showing organizing pneumonia in 16 (32%) patients, interstitial pneumonitis in 9 (18%) patients, hypersensitivity pneumonitis in 4 (8%) patients, and patchy interstitial fibrosis in 4 (8%) patients. In the remaining 17 (34%) patients, the histological findings were normal or with mild nonspecific changes or related to smoking.

Conclusions: This study has evaluated histologically patients with suspected DILD after COVID-19 and confirm it in 66% of them. Modification of the usual TBC technique using single-use FB and cryoprobe is safe and provides a high diagnostic yield.