Thromboembolism in COVID-19: the unsolved problem

INTRODUCTION: The recent Sars-CoV-2 pandemic (COVID-19) has led to growing research to explain the poor clinical prognosis in some patients. While early observational studies highlighted the role of the virus in lung failure, in a second moment thrombosis emerged as a possible explanation of the worse clinical course in some patients. Despite initial difficulties in management of such patients, the constant increase of literature in the field is to date clarifying some questions from clinicians. However, several other questions need answer. EVIDENCE ACQUISITION: We performed systematic research using Embase and PubMed, inserting the keywords and mesh terms relative to the new coronavirus and to VTE: "COVID-19," "SARS," "MERS," "coronavirus," "2019 n-CoV," venous thromboembolism," "pulmonary embolism," "deep vein thrombosis," "thromboembolism," "thrombosis." Boolean operators "AND," "OR," "NOT" were used where appropriate. We found 133 articles of interest but only 20 were selected, providing the most representative information. EVIDENCE SYNTHESIS: A novel disease (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) infection was responsible for thousands of hospitalizations for severe acute respiratory syndrome, with several cases of thrombotic complications due to excessive inflammation, platelet activation, endothelial dysfunction, and stasis. COVID-19 and hospitalizations for COVID-19 may carry several potential risk factors for thrombosis. Severe coagulation abnormalities may occur in almost all the severe and critical ill COVID-19 cases. CONCLUSIONS: Despite a strong pathophysiological rationale, the evidence in literature is not enough to recommend an aggressive antithrombotic therapy in COVID-19. However, it is our opinion that an early use, even at home at the beginning of the disease, could improve the clinical course.