D-dimer in VTE may not extrapolate to COVID-19
“The D-dimer test, which is a measure of circulating byproducts of blood clot dissolution, has long been incorporated into diagnostic algorithms for venous thromboembolic [VTE] disease, including deep vein thrombosis and pulmonary embolism. It is uncertain whether this diagnostic use of D-dimer testing can be extrapolated to the context of COVID-19 – an illness we now understand to be associated itself with intravascular thrombosis and fibrinolysis,” Matthew Tomey, MD, a cardiologist at Mount Sinai Morningside, New York, said in an interview.
“The authors of this study sought to evaluate the test characteristics of the D-dimer assay for diagnosis of pulmonary embolism in a consecutive series of 287 hospitalized patients with COVID-19 who underwent computed tomography pulmonary angiography (CTPA). This was a selected group of patients representing less than 20% of the 1,541 patients screened. Exclusion of data on the more than 80% of screened patients who did not undergo CTPA is a significant limitation of the study,” Dr. Tomey said.
“In the highly selected, small cohort studied, representing a group of patients at high pretest probability of pulmonary embolism, there was no patient with pulmonary embolism who had a D-dimer value less than 0.5 mcg/mL. Yet broad ranges of D-dimer values were observed in COVID-19 patients with (0.5 to >10,000 mcg/mL) and without (0.2 to 128 mcg/mL) pulmonary embolism,” he added.
Based on the presented data, it is likely true that very low levels of D-dimer decrease the likelihood of finding a pulmonary embolus on a CTPA, if it is performed, Dr. Tomey noted.
“Yet the data confirm that a wide range of D-dimer values can be observed in COVID-19 patients with or without pulmonary embolism. It is not clear at this time that D-dimer levels should be used as gatekeepers to diagnostic imaging studies such as CTPA when pretest suspicion of pulmonary embolism is high,” he said.
“This issue becomes relevant as we consider evolving data on use of anticoagulation in treatment of hospitalized patients with COVID-19. Wethat in critically ill patients hospitalized with COVID-19, routine therapeutic anticoagulation (with heparin) was not beneficial and potentially harmful when compared with usual thromboprophylaxis,” he concluded.
“As we strive to balance competing risks of bleeding and thrombosis, accurate diagnosis of pulmonary embolism is important to guide decision-making about therapeutic anticoagulation, including in COVID-19.”
Dr. Logothetis and Dr. Tomey have disclosed no relevant financial relationships.
A version of this article first appeared on.