Effect of reduced saturation and elevated D-dimer and interleukin 6 levels on vessel density and foveal avascular zone in patients with COVID-19 bilateral pneumonia

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can affect multiple organs, including the eyes.

Objectives: This study aimed to identify associations between vascular density (VD) and the foveal avascular zone (FAZ), assessed using optical coherence tomography angiography (OCTA), and baseline levels of D-dimers and interleukin 6 (IL-6) in patients with bilateral COVID-19 pneumonia, depending on oxygen saturation (SpO2) on admission.

Material and methods: The study included patients with COVID-19 bilateral pneumonia due to SARS-CoV-2 infection who were hospitalized between March and May 2021. Ophthalmological examination was performed 2 months after hospitalization. Optical coherence tomography angiography was used for the automatic assessment of the central retinal VD and the manual assessment of FAZ.

Results: A significant monotonic negative relationship was observed between SpO2 . 90% and VD in some areas of the superficial capillary plexus (SCP) (p = 0.048) and choriocapillaris (p = 0.021), and the mean VD in the deep capillary plexus (DCP) (p = 0.048). No significant monotonic negative relationship was noted between SpO2 . 90% and the FAZ in the SCP (p = 0.075). However, there was a significant monotonic positive relationship between VD in the nasal choriocapillaris and D-dimer levels in patients with SpO2 . 90% (p = 0.003, respectively). Finally, a monotonic negative relationship was identified between foveal VD in the DCP and IL-6 levels in patients with SpO2 . 90% (p = 0.027).

Conclusions: An OCTA study conducted 2 months after hospitalization for COVID-19 bilateral pneumonia showed reduced VD in those with SpO2 . 90% and elevated levels of D-dimers and IL-6 during hospitalization. Optical coherence tomography angiography testing can provide monitoring of ocular status in patients following SARS-CoV-2 infection, especially those who report visual disturbances.

Keywords: COVID-19; foveal avascular zone; optical coherence tomography angiography; oxygen saturation; vessel density.