Sustained inflammation, coagulation activation and elevated endothelin-1 levels without macrovascular dysfunction at 3 months after COVID-19

INTRODUCTION

Endothelial damage and thrombosis caused by COVID-19 may imperil cardiovascular health. More than a year since the WHO declared COVID-19 pandemic, information on its effects beyond the acute phase is lacking. We investigate endothelial dysfunction, coagulation and inflammation, 3 months post-COVID-19.

MATERIALS AND METHODS

A cohort study was conducted including 203 patients with prior COVID-19. Macrovascular dysfunction was assessed by measuring the carotid artery diameter in response to hand immersion in ice-water. A historic cohort of 312 subjects served as controls. Propensity score matching corrected for baseline differences. Plasma concentrations of endothelin-1 were measured in patients post-COVID-19, during the acute phase, and in matched controls. Coagulation enzyme:inhibitor complexes and inflammatory cytokines were studied.

RESULTS AND CONCLUSIONS

The prevalence of macrovascular dysfunction did not differ between the COVID-19 (18.6%) and the historic cohort (22.5%, RD -4%, 95%CI: -15-7, p = 0.49). Endothelin-1 levels were significantly higher in acute COVID-19 (1.67 ± 0.64 pg/mL) as compared to controls (1.24 ± 0.37, p < 0.001), and further elevated 3 months post-COVID-19 (2.74 ± 1.81, p < 0.001). Thrombin:antithrombin(AT) was high in 48.3%. Markers of contact activation were increased in 16-30%. FVIIa:AT (35%) and Von Willebrand Factor:antigen (80.8%) were elevated. Inflammatory cytokine levels were high in a majority: interleukin(IL)-18 (73.9%), IL-6 (47.7%), and IL-1ra (48.9%). At 3 months after acute COVID-19 there was no indication of macrovascular dysfunction; there was evidence, however, of sustained endothelial cell involvement, coagulation activity and inflammation. Our data highlight the importance of further studies on SARS-CoV-2 related vascular inflammation and thrombosis, as well as longer follow-up in recovered patients.

Sustained endothelial, coagulation and inflammatory cytokine activation without macrovascular dysfunction at 3 months after COVID-19: a reflection on SARS-CoV-2 induced thrombo-inflammation

Background

Endothelial damage caused by COVID-19 may imperil the cardiovascular health of millions. More than a year since WHO declared the COVID-19 pandemic, information on the lasting effects of this infection on the cardiovascular system beyond the acute phase is still lacking.

Purpose

To study macrovascular endothelial dysfunction and activation, coagulation and inflammation, 3 months after resolution of acute COVID-19 symptoms.

Methods

A cross-sectional observational cohort study was conducted including 203 patients with PCR confirmed COVID-19 disease, 6–20 weeks after acute COVID-19. The primary endpoint was macrovascular endothelial function, assessed by the carotid artery reactivity (CAR) test. The CAR measures the carotid artery diameter in response to hand in ice-water immersion. A historic cohort of 313 subjects served as controls. Propensity score matching was used to correct for baseline differences. Plasma endothelin-1 (ET-1), interleukin (IL)-1ra, IL-6, IL-18 were measured by ELISA. ET-1 levels were also measured in a partially overlapping COVID-19 cohort of which plasma samples were available during the acute phase. Coagulation enzyme:inhibitor complexes for thrombin:antithrombin (TAT), factor (F) IXa:AT, FVIIa:AT, FXIa:AT, FXIa:alpha 1 antitrypsin (a1AT), FXIa:C1 esterase inhibitor (C1inh), kallikrein(PKa):C1inh and von Willebrand Factor:antigen (vWF:Ag), were assessed by in house developed ELISA.

Results

After propensity score matching, the prevalence of macrovascular dysfunction did not differ between the COVID-19 (22.5%) versus the historical control cohort (18.6%, RD −3.92%, 95%-CI −15 to 7.19, p=0.49). Plasma concentrations of markers for endothelial activation were elevated (>1 SD above normal); ET-1 (64.9%), and vWF:Ag (80.8%). In controls, ET-1 levels were significantly lower as compared to COVID-19 patients during the acute phase and after 3 months. ET-1 levels were significantly higher 3 months after COVID-19 as compared to the acute phase. Cytokines were high in a majority of patients: IL-18 (73.9%), IL-6 (51.2%), and IL-1ra (48.9%). TAT and FIXa:AT, reflecting a prothrombotic state, were high in 48.3% and 29.6% of the patients, respectively. FVIIa:AT, as marker of the extrinsic pathway, was elevated (35%). Markers of contact activation were also increased: PKa:C1inh (16.3%), FXIa:AT (16.3%), FXIa:a1AT (20.7%), and FXIa:C1inh (17.7%) (picture 1).

Conclusions

At 3 months after acute COVID-19 there was no indication of macrovascular dysfunction as compared to matched historic controls; there was evidence, however, of sustained thrombo-inflammation, indicated by high circulating concentrations of ET-1, vWF:Ag, proinflammatory cytokines, and markers of coagulation (picture 2). Elevated IL-18 levels could potentially induce arterial inflammation and subsequent atherogenesis. Our data highlight the importance of further studies on SARS-CoV-2 related thrombo-inflammation, as well as longer follow-ups in recovered patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by a grant from The Netherlands Organisation for Health Research and Development (ZonMw).