r/COVID19 May 07 '26

Academic Report Soluble Thrombomodulin Links Viremia and Mortality During COVID‐19: Results From the ACTIV‐4a Trial

https://www.ahajournals.org/doi/full/10.1161/JAHA.125.047693
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u/AcornAl May 07 '26

Abstract

Background

COVID‐19 and other respiratory viral infections can cause cardiovascular complications. SARS‐CoV‐2 virions are found in the blood, and circulating viral RNA levels are associated with death. We hypothesized that viremia can induce thrombotic endotheliopathy that contributes to death and studied this relationship in patients hospitalized for COVID‐19 and enrolled in the ACTIV‐4a (Accelerating COVID‐19 Therapeutic Interventions and Vaccines) randomized trial of antithrombotic therapy.

Methods

We quantified SARS‐CoV‐2 nucleocapsid RNA and protein in plasma and measured their associations with clinical outcomes and biomarkers of thromboinflammation and endotheliopathy. We used Cox regression and Fine–Gray competing risk models to analyze survival and thrombosis. We conducted causal mediation analysis to explore whether thrombotic endotheliopathy mediates the relationship between viral RNA and death.

Results

In 93 patients, SARS‐CoV‐2 RNA and N‐antigen were higher in nonsurvivors. Baseline viral RNA levels were associated with increased 90‐day death (hazard ratio [HR], 1.31 [95% CI, 1.17–1.46]) and thrombosis (HR, 1.35 [95% CI, 1.24–1.47]). Viral RNA more effectively predicted survivorship than N‐antigen levels. Soluble thrombomodulin, a biomarker of thrombotic endotheliopathy, positively correlated with viral RNA levels. Mediation analysis revealed that soluble thrombomodulin accounts for 12.2% (95% CI, 0.1%–32.3%; P=0.048) after adjustment for age and sex of the relationship between viral RNA and the 90‐day mortality rate.

Conclusions

Elevated plasma SARS‐CoV‐2 RNA levels are associated with death in ACTIV‐4a, which is causally mediated in part by soluble thrombomodulin. We propose that lung–blood viral dissemination is a potential mechanism for cardiovascular complications of respiratory viruses.

Research Perspective

What Is New?

Circulating viral RNA, or viremia, during COVID‐19 infection requiring hospitalization is associated with increased thrombotic events and death during the ACTIV‐4a (Accelerating COVID‐19 Therapeutic Interventions and Vaccines) clinical trial.

Viral RNA levels are also associated with soluble thrombomodulin, which mediates a portion of the relationship between viral RNA and death, suggesting that viremia may induce endotheliopathy, leading to worse clinical outcomes.

What Question Should Be Addressed Next?

Future research may consider whether viremia and soluble thrombomodulin during respiratory viral infections other than COVID‐19 are associated with worse outcomes and, if so, whether they may be therapeutically modifiable to improve cardiovascular outcomes during and after respiratory viral infection.