Post-acute COVID-19 syndrome (PACS) has been linked to microvascular endothelial dysfunction as a potential underlying pathomechanism and can manifest even following a mild course of the initial infection. Prevalence of microvascular endothelial dysfunction and circulating natriuretic peptides in such PACS patients remains unknown.

This prospective, cross-sectional cohort study enrolled 92 patients (82% females, median age 48 years) with PACS. Reactive hyperemia index (RHI) was evaluated with peripheral arterial tonometry, where <1.67 was defined as microvascular endothelial dysfunction, 1.67-2.0 as impaired function, and >2 normal endothelial function, on average 31 months after the acute infection. N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were collected at 2 different time points within over a 1-year span.

In total, 41% of PACS subjects had microvascular endothelial dysfunction and 20% had impaired RHI. No major differences in clinical characteristics, routine chemistry laboratory testing, or symptom burden were observed across the groups. Only subjects with microvascular endothelial dysfunction and impaired endothelial function had a significant increase in NT-proBNP levels over time, and those with larger increase in NT-proBNP had significantly lower RHI. There was a significant correlation between relative or absolute increase in NT-proBNP and RHI, which remained significant in a multivariable adjusted linear regression.

Peripheral microvascular endothelial dysfunction was prevalent in a symptomatic PACS population long after recovery from a mild acute infection. Increases in NT-proBNP levels were associated with microvascular endothelial dysfunction, suggesting a link between, and providing a foundation for, future studies on post viral microvascular endothelial dysfunction in PACS.

Ninety-two subjects with post-acute COVID-19 were enrolled in this prospective cohort study. Subjects contracted acute COVID-19 during the first wave. N-terminal pro-B-type natriuretic peptide (NT-proBNP) 1 and symptom evaluation were performed around 10 months after the acute infection. Around 2-3 years after the acute infection, an additional NT-proBNP was collected and evaluation of microvascular endothelial function with reactive hyperemia index (RHI) as readout was performed. Forty-one percent of the subjects had microvascular endothelial dysfunction microvascular endothelial dysfunction (MVD) and 20% had impaired RHI. These 2 groups had increase in NT-proBNP levels, whereas no change in NT-proBNP levels was observed in the group with normal RHI. A significant correlation between microvascular function in all patients and delta or relative change in NT-proBNP levels was observed. No major differences were observered in clinical characteristics.