Based on recent reports that demonstrated a strong association between elevated D-dimer levels and poor prognosis, concerns have risen about thrombotic complications in patients with COVID-19. To address these concerns, the National Institute for Public Health of the Netherlands asked a group of radiology and vascular medicine experts to provide guidance for the imaging workup and treatment of these important complications.

A report published in Radiology outlines prevention, diagnosis, and treatment of complications stemming from blood clots in patients with COVID-19. The journal also published two research letters and a case study on this topic.

“Worldwide, COVID-19 is being treated as a primary pulmonary disease,” said Edwin J.R. van Beek, MD, PhD, director at Edinburgh Imaging, Queens Medical Research Institute, at the University of Edinburgh, U.K. “From the analysis of all available current medical, laboratory, and imaging data on COVID-19, it became clear that symptoms and diagnostic tests could not be explained by impaired pulmonary ventilation alone.”

Recent observations suggest that respiratory failure in COVID-19 is not driven by the development of the acute respiratory distress syndrome alone, but that microvascular thrombotic processes may play a role. This may have important consequences for the diagnostic and therapeutic management of these patients. There is a strong association between D-dimer levels, disease progression, and chest CT features suggesting venous thrombosis. In addition, various studies in patients with COVID-19 have shown a very strong association between increased D-dimer levels and severe disease and poor prognosis.

The report authors stress that careful attention needs to be paid to the initial diagnosis and treatment of the prothrombotic and thrombotic state that can occur in a substantial percentage of COVID-19 patients.

“Imaging and pathological investigations confirmed the COVID-19 syndrome is a thrombo-inflammatory process that initially affects lung perfusion but consecutively affects all organs of the body,” Professor van Beek said. “This highly thrombotic syndrome leads to macro-thrombosis and embolism. Therefore, strict thrombosis prophylaxis, close laboratory, and appropriate imaging monitoring with early anticoagulant therapy in case of suspected venous thromboembolism are indicated.”

Recommendations for diagnostic and therapeutic management, which vary based on patient symptoms and risk profiles, include prophylactic-dose heparin, chest CT, CT pulmonary angiography, and routine D-dimer testing.

Findings have also emerged linking COVID-19 more specifically with pulmonary embolism. A research letter from Hôpitaux Universitaires de Strasbourg published in Radiology reported that of 106 pulmonary CT angiograms performed for COVID-19 patients over a 1-month period in a tertiary-care center in France, 32 patients (30%) had acute pulmonary embolus (PE). This rate of PE is much higher than usually encountered in critically ill patients without COVID-19 infection (1.3%) or in emergency department patients (3%-10%).