Elevated cerebral oxygen extraction in patients with post-COVID conditions.

Abstract

Objectives: Dysfunction of cerebral microcirculation due to SARS-CoV-2 infection has been postulated to be a plausible mechanism for the neurological symptoms of post-COVID-19 conditions (neuro-PCC), affecting oxygen homeostasis in the brain. In this study, we aimed to investigate the balance between cerebral oxygen delivery and consumption, measured by oxygen extraction fraction (OEF), in patients with neuro-PCC.

Methods: 25 participants with neuro-PCC (8 previously hospitalized and 17 not hospitalized) and 59 age-matched healthy controls were studied. Global OEF was quantified using TRUST MRI and compared across the three groups. Associations between OEF and neurobehavioral measures were also evaluated in participants with neuro-PCC.

Results: OEF was significantly different (one-way ANCOVA-p=0.046) among the three groups, after accounting for age and sex. On post-hoc analyses, previously hospitalized neuro-PCC participants had significantly higher OEF (42.40 ± 5.40 %) than both uninfected controls (37.70 ± 5.09 %, p=0.032) and neuro-PCC participants without hospitalization (37.02 ± 5.05 %, p=0.015). Within the participants with neuro-PCC, OEF was significantly associated with locomotor function assessed with the 4-m walk gait speed score (β=-0.03, r=0.34, p=0.003).

Conclusions: Participants with neuro-PCC had altered cerebral OEF, which is also associated with slower locomotion. OEF is a promising marker for studying neuro-PCC.