header-image

Hematology for the COVID-19 Frontline



Hematology for the COVID-19 Frontline

Ghaith Abu-Zeinah, MD

Instructor in Medicine
Division of Hematology and Oncology
Weill Cornell Medicine


It has become rapidly evident that COVID-19, the disease caused by the novel SARS-CoV-2 virus, is a multi-organ system disease with several hematologic manifestations. COVID-19 associated coagulopathy (CAC) and thromboembolism aremajor hematologic complications of COVID-19 that result inhigh morbidity and poor prognosis. It is important to recognize that CAC, unlike DIC from other critical illnesses, is primarily associated with a thrombotic rather than a hemorrhagic phenotype. Moreover, thrombosis in COVID-19 patients, as shown in autopsy studies,has an affinity for the pulmonary microvasculature but mayalso involve larger blood vessels, both veins and arteries, and occur in virtually any organ.

CAC,and the ensuing thrombotic predilection, can range from mild to severe. The severityof CACis linked to the host’s inflammatory response to the pathogen: severe cases are typically observed in critically ill patients with systemic hyperinflammation from a cytokine storm.The severity of CAC can be objectified using the SIC and DIC scoring systems developed by the ISTH. In these equations, the D-dimer elevation and its trend during hospitalization plays a major role in quantifying severity and predicting outcomes. Assessing the severity of CAC is important because it helps in clinical decision making with regards to anticoagulant therapy. Anticoagulation is considered essential to the management of all hospitalized COVID-19 patients but the optimal dosing is an area of ongoing investigation.

Additional therapies for primary prevention or treatment of thrombotic complications are emergingas we learn more about pathogenesis. Drugs that inhibit the inflammatory and complement activation pathways have served an experimental role because both the cytokine-mediated inflammatory response and the complement cascade have been implicated in the pathogenesis of thrombosis in COVID-19. Anecdotal evidence suggests that combining anti-inflammatory and anti-complement approach withanti-coagulation maybe effective in refractory cases of COVID-19 thrombosis and multi-organ dysfunction.

As a medical community, we have come a long way learning how to treat this disease and its complications. As a global community, however, we still have a long wayto go to eradicate this pandemic. The best way to prevent the complications of SARS-CoV-2 is to avoid getting it and stop spreading it. The most important clinical pearl is one that reminds us to stay current and follow public health recommendations.

References:

  1. Spyropoulos AC, Levy JH, Ageno W, Connors JM, Hunt BJ, Iba Tet al.Scientific and Standardization Committee communication: Clinical guidance on the diagnosis, prevention, and treatment of venous thromboembolism in hospitalized patients with COVID‐19.J Thromb Haemost2020;18: 1859–1865.
  2. Connors JM, Levy JH. COVID-19 and its implications for thrombosis and anticoagulation.Blood2020;135: 2033–2040.
  3. COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 (COVID-19) Treatment Guidelines. National Institutes of Health. Available at https://www.covid19treatmentguidelines.nih.gov/. Accessed 9/3/20