Author: Denise Baez
The American Society of Hematology (ASH) has published new guidelines on the use of anticoagulation for thromboprophylaxis in patients with coronavirus disease 2019 (COVID-19) who are acutely ill or hospitalised and do not have confirmed or suspected venous thromboembolism (VTE).
Although the optimal strategy for thromboprophylaxis in these patients remains uncertain, the panel issued conditional recommendations in favour of prophylactic-intensity anticoagulation over intermediate-intensity or therapeutic-intensity anticoagulation for patients with COVID-19-related critical illness or acute illness who do not have confirmed or suspected VTE.
This recommendation does not apply to patients who require anticoagulation to prevent thrombosis of extracorporeal circuits such as those on extracorporeal membrane oxygenation or continuous renal replacement therapy.
Patients with critical illness are defined as those suffering from an immediately life-threatening condition who would typically be admitted to an intensive care unit, such as patients requiring haemodynamic support, ventilatory support, and renal-replacement therapy. Patients with acute illness are defined as those with clinical features that would typically result in admission to a medicine inpatient ward without requirement for advanced clinical support, such as patients with dyspnoea or mild to moderate hypoxia.
“These recommendations were based on very low certainty in the evidence, underscoring the need for high-quality, randomised controlled trials comparing different intensities of anticoagulation,” the panel wrote.
The guideline, published in Blood Advances, will be updated when the full results of REMAP-CAP, ACTIV-4, and ATTACC become available.
“We conducted new systematic reviews to establish the base recommendation in our first phase,” the authors wrote. “We will use existing systematic reviews to supplement our ongoing living reviews.”
In the meantime, clinicians should weigh the potential benefits and harms based on the most up-to-date available evidence in caring for their patients. The guideline recommends an individualised assessment of the patient’s risk of thrombosis and bleeding when deciding on anticoagulation intensity. The panel acknowledged that higher-intensity anticoagulation may be preferred for patients judged to be at high thrombotic risk and low bleeding risk.
The selection of a specific agent for thromboprophylaxis may be based on availability, resources required, familiarity, and the aim of minimising use of personal protective equipment or staff exposure to COVID-19-infected patients, as well as patient-specific factors (ie, renal function, history of heparin-induced thrombocytopenia, concerns about gastrointestinal tract absorption).