ED-ACT, Examining D-dimer and Empiric Anticoagulation in COVID-19 Related Thrombosis

Document Type

Conference Proceeding

Publication Date


Publication Title

Annals of Emergency Medicine



Thrombosis is thought to occur frequently in the setting of acute SARS-CoV-2 infection. We aimed to elucidate the relationship between macro/micro vascular thrombosis, D-dimer levels, and empiric anticoagulation in acute COVID-19.


This was an exploratory prospective, single-site, observational study. Adult emergency department patients with COVID-19 requiring hospitalization received a point-of-care lower extremity ultrasound. Relevant clinical and demographic data were obtained by review of the electronic medical record. The primary endpoint was venous thromboembolism and associated D-dimer level. Secondary endpoints included rates of micro and macro thrombotic complications as well as empiric anticoagulant use.


Between January 13th and April 12th 2021, 52 patients were enrolled. Median age was 55, 52% of patients were male. Median D-dimer at ED presentation was 650 ng/mL (range 250 to 10,000 ng/mL), among patients with negative duplex studies. One patient had a confirmed pulmonary embolism with a D-dimer of 5,082 ng/mL. During hospitalization, 18 patients underwent 20 studies assessing for VTE yielded one DVT event. Among patients with negative studies median D-dimer was 1,246 ng/mL (range 329-10,000 ng/mL). Two patients experienced microvascular complications. Seven patients were started on empiric full dose anticoagulation, with one non-severe bleeding event.


While VTE remains a major concern amongst patients with COVID-19, the normal D-dimer cut off of >500 ng/mL likely should not be used as a trigger to initiate further VTE workup. Additionally, mildly to moderately elevated D-dimer did not correlate strongly with microvascular complications and may not be relevant in the decision to initiate empiric full dose anticoagulation. · Classic D-dimer cut offs are likely unreliable in acute COVID-19. · Significantly elevated D-dimer in acute COVID-19 may be helpful in triggering a VTE workup. · Without evidence of VTE, D-dimer alone should not be used to initiate empiric AC in COVID-19. · Future research should focus on how best to utilize D-dimer for risk stratification in acute COVID-19.




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American College of Emergency Physicians Research Forum, San Francisco, CA, October 1-4, 2022.