In-vivo evidence of systemic endothelial vascular dysfunction in COVID-19.

"Declaration of Competing Interest The authors state that they do not have any conflict of interest related with the submitted study."

"This is a prospective, observational, case-control, and blinded study conducted from June 1 through November 20, 2020. The study included patients with history of COVID-19 that underwent assessment of vascular endothelial function in Hospital Clinico San Carlos, Madrid, Spain, at different stages of infection: group 1, constituted by patients assessed during acute phase of COVID-19 as documented by nasal swabs polymerase-chain-reaction assay (PCR); and group 2, constituted by patients assessed during post SARS-CoV-2 infection stage as documented by repeated negative PCR during follow-up. In addition, assessment of vascular endothelial function was repeated at post infection stage in patients within group 1. To assess the effect of SARS-CoV-2 infection on vascular endothelial function, the endothelial function in COVID-19 patients was compared with a matched control group comprised by subjects selected from an historical, pre-COVID 19 pandemic cohort of volunteers who underwent PAT evaluation as part of baseline assessment of cardiovascular risk at Mayo Clinic (Rochester, MN, USA). Written informed consent was obtained from all the participants, and the protocol was approved by local institutional review board (20/451-E COVID). The study was registered at ClinicalTrials (NCT04525443)."