Analysis of Risk Factors for Tracheal Stenosis Managed during COVID-19 Pandemic: A Retrospective, Case-Control Study from Two European Referral Centre

Introduction: Benign subglottic/tracheal stenosis (SG/TS) is a life-threatening condition commonly caused by prolonged endotracheal intubation or tracheostomy. Invasive mechanical ventilation was frequently used to manage severe COVID-19, resulting in an increased number of patients with various degrees of residual stenosis following respiratory weaning. The aim of this study was to compare demographics, radiological characteristics, and surgical outcomes between COVID-19 and non-COVID patients treated for tracheal stenosis and investigate the potential differences between the groups. Materials and methods: We retrospectively retrieved electronical medical records of patients managed at two referral centers for airways diseases (IRCCS Humanitas Research Hospital and Avicenne Hospital) with tracheal stenosis between March 2020 and May 2022 and grouped according to SAR-CoV-2 infection status. All patients underwent a radiological and endoscopic evaluation followed by multidisciplinary team consultation. Follow-up was performed through quarterly outpatient consultation. Clinical findings and outcomes were analyzed by using SPPS software. A significance level of 5% (p < 0.05) was adopted for comparisons. Results: A total of 59 patients with a mean age of 56.4 (+/- 13.4) years were surgically managed. Tracheal stenosis was COVID related in 36 (61%) patients. Obesity was frequent in the COVID-19 group (29.7 +/- 5.4 vs. 26.9 +/- 3, p = 0.043) while no difference was found regarding age, sex, number, and types of comorbidities between the two groups. In the COVID-19 group, orotracheal intubation lasted longer (17.7 +/- 14.5 vs. 9.7 +/- 5.8 days, p = 0.001), tracheotomy (80%, p = 0.003) as well as re-tracheotomy (6% of cases, p = 0.025) were more frequent and tracheotomy maintenance was longer (21.5 +/- 11.9 days, p = 0.006) when compared to the non-COVID group. COVID-19 stenosis was located more distal from vocal folds (3.0 +/- 1.86 vs. 1.8 +/- 2.03 cm) yet without evidence of a difference (p = 0.07). The number of tracheal rings involved was lower in the non-COVID group (1.7 +/- 1 vs. 2.6 +/- 0.8 p = 0.001) and stenosis were more frequently managed by rigid bronchoscopy (74% vs. 47%, p = 0.04) when compared to the COVID-19 group. Finally, no difference in recurrence rate was detected between the groups (35% vs. 15%, p = 0.18). Conclusions: Obesity, a longer time of intubation, tracheostomy, re-tracheostomy, and longer decannulation time occurred more frequently in COVID-related tracheal stenosis. These events may explain the higher number of tracheal rings involved, although we cannot exclude the direct role of SARS-CoV-2 infection in the genesis of tracheal stenosis. Further studies with in vitro/in vivo models will be helpful to better understand the role of inflammatory status caused by SARS-CoV-2 in upper airways.