Can we optimize d-dimer cut off value to predict pulmonary embolism in covid-19 patients?

Abstract Background Covid-19 is associated with an increased risk of pulmonary embolism (PE) therefore, should the cut off d-dimer value be adjusted for these patients? Material and methods Retrospective and observational study to understand if there is a d-dimer cut-off that could guide clinics to perform a thoracic computed tomography angiography (CTA) in patients with covid-19. The population was covid-19 patients admitted to covid-19 dedicated wards of a University Hospital Centre for one year. Results and conclusions 725 (52%) patients with covid-19 had a d-dimer value dosed during the first 5 days of the disease. Those, 63 (9%) did a CTA with a diagnosis of 16 (25%) PE. Gender was equally represented, median age was 70 years (ID = 3.49) and the majority (94%) survived. Thirteen (81%) patients with PE had a d-dimer value above 2500 ng/mL (OR = 9.244, 95% CI 2.248–9.837), with 7 (54%) with values over 10000 ng/mL, but in 3 (9%) it was under 1500 ng/mL. Seventy-three (63%) of patients with a d-dimer over 1500 ng/mL did not had a thoracic CTA performed. In our population PE was not a frequent outcome. The results are influenced by the low number of thoracic CTA performed because, even tough the cut-off d-dimer value used at our hospital to perform a thoracic CTA to exclude PE is 1500 ng/mL, most patients with that d-dimer value did not take the exam and so PE could not be excluded. Although in most PE cases the d-dimer value was above 2500 ng/mL, the results of our study cannot verify if that is a better cut-off value.