Severe SARS-CoV-2 pneumonia: Clinical, functional and imaging outcomes at 4 months

Abstract

Introduction: Given the pathophysiology of coronavirus disease 19 (COVID-19), persistent pulmonary abnormalities are likely. Methods:We conducted a prospective cohort study in severe COVID-19 patients who had oxygen saturation <94% and were primarily admitted to hospital. We aimed to describe persistent gas exchange abnormalities at 4 months, defined as decreased diffusing capacity of the lungs for carbon monoxide (DLco) and/or desaturation on the 6-minute walk test (6MWT), along with associated mechanisms and risk factors Results: Of the 72 patients included, 76.1% required admission to the intensive care unit (ICU), while 68.5% required invasive mechanical ventilation (MV). 39.1% developed venous thromboembolism (VTE). At 4 months, 61.4% were still symptomatic. Functionally, 39.1% had abnormal carbon monoxide test results and/or desaturation on 6MWT; high-flow oxygen, MV, and VTE during the acute phase were significantly associated. Restrictive lung disease was observed in 23.6% of cases, obstructive lung disease in 16.7%, and respiratory muscle dysfunction in 18.1%. A severe initial presentation with admission to ICU (p=.0181), and VTE occurrence during the acute phase (p=.0089) were associated with these abnormalities. 41% had interstitial lung disease in computed tomography (CT) of the chest. Four patients (5.5%) displayed residual defects on lung scintigraphy, only one of whom had developed VTE during the acute phase (5.5%). The main functional respiratory abnormality (31.9%) was reduced capillary volume (Vc<70%). Conclusion: Among patients with severe COVID-19 pneumonia who were admitted to hospital, 61% were still symptomatic, 39% of patients had persistent functional abnormalities and 41% radiological abnormalities after 4 months. Embolic sequelae were rare but the main functional respiratory abnormality was reduced capillary volume. A respiratory check-up after severe COVID-19 pneumonia may be relevant to improve future management of these patients.

Identification of factors impairing exercise capacity after severe COVID-19 pulmonary infection: a 3-month follow-up of prospective COVulnerability cohort

“…We also found that an impaired exercise capacity was associated with a lower lung function and particularly with a decrease in lung volume that characterized COVID-19 survivors [ 8 , 9 , 22 , 30 , 31 ]. A reduction of gas transfer measured by DL CO was also present, but this difference disappeared when this value was related with alveolar ventilation (K CO ), confirming the restrictive pulmonary pattern in patients presenting a decreased effort capacity.…”

Reply to Noel-Savina and collaborators: DM and VC impairment after COVID-19

“…Indeed, this technique allows distinguishing between reductions of alveolar membrane diffusive conductance (D M ) and pulmonary capillary blood volume (V C ) [3] , [4] , [5] . Noel-Savina and collaborators reported a slight decrease in median V C in their cohort, and a preserved median D M [1] . This result drew our attention, because the opposite was found in two other monocentric series in which patients were reassessed after in-hospital treatment for COVID-19 pneumonia: one Italian study with 94 patients [6] , and one Spanish work with 200 subjects [7] .…”

“…TO THE EDITOR: We read with great interest the article of Noel-Savina and collaborators, from Toulouse university hospital (France), about the outcomes of 72 patients with coronavirus disease 2019 (COVID-19) pneumonia, at 4 months after hospital discharge [1] . In their monocentric cohort, 76% of patients were admitted to intensive care unit.…”

Protection by metformin against severe Covid-19: An in-depth mechanistic analysis

“…This finding indicates that SARS-CoV-2 infection strongly affects processes that are specific to small vessels [126] . It is particularly noteworthy that one study observed the persistence of vascular dysfunction in patients convalescing from Covid-19 [127] – possibly due to the persistence of ACE2 activity in plasma [128] and a lasting reduction in capillary volume [129] .…”