Preliminary reports suggest that hemostatic abnormalities, including disseminated intravascular coagulation (DIC), occur in patients affected by COVID-19. Additionally, the severe inflammatory response, critical illness, and underlying traditional risk factors may all predispose to thrombotic events, similar to prior virulent zoonotic coronavirus outbreaks. Second, investigational therapies for treating COVID-19 may have adverse drug-drug interactions with antiplatelet agents and anticoagulants. In the current review-opinion based manuscript the authors raised some important points and recommendations for patients with COVID-19 who develop venous or arterial thrombosis, and of those with preexisting thrombotic disease who develop COVID-19, or those who need prevention or care for their thrombotic disease during the COVID-19 pandemic.
Considering the severity of the disease, the recommendations are presented in a severity based scale.
Patients with mild COVID-19 (outpatient)
- Increased mobility should be encouraged. Pharmacologic prophylaxis could be considered after risk assessment on an individual case basis for patients who have elevated risk VTE, without high bleeding risk.
- There is no known risk of developing severe COVD-19 due to taking antithrombotic agents (i.e. antiplatelet agents or anticoagulants). If patients have been taking antithrombotic agents for prior known thrombotic disease, they should continue their antithrombotic agents as recommended. For outpatients on vitamin K antagonists who do not have recent stable INRs, and are unable to undergo home or drive-through INR testing, it is reasonable to transition the treatment DOACs [Direct Oral Anticoagulants] if there are no contraindications and no problems with drug availability and affordability. If DOACs are not approved or available, low-molecular weight heparin can be considered as alternative.
Patients with moderate or severe COVID-19 without DIC [Disseminated intravascular coagulation ] (hospitalized)
- For hospitalized patients with COVID-19 and not in DIC, prophylactic doses of anticoagulation can be administered to prevent VTE.
- If pharmacological prophylaxis is contraindicated, it is reasonable to consider intermittent pneumatic compression.
- For hospitalized patients with COVID-19 and not in DIC, there is insufficient data to consider routine therapeutic or intermediate-dose parenteral anticoagulation with UFH or LMWH.
- Routine screening for VTE (e.g. bilateral lower extremity ultrasound) for hospitalized patients with COVID-19 with elevated D-Dimer (>1,500 ng/mL) cannot be recommended at this point.
- Prophylactic doses of LMHW in patients with hospitalized patients with moderate or severe COVID-19 and without DIC to prevent VTE.
- Monitoring anti Xa activity could be an option for determining the optimal dose of prophylactic anticoagulation.
- Extended prophylaxis (for up to 45 days) is reasonable for patients with elevated risk of VTE (e.g., reduced mobility, co-morbidities such as active cancer) and low risk of bleeding.
Areas requiring further investigation:
- To develop an appropriate algorithm for the diagnosis of incident VTE in patients with COVID-19 (D-dimer is elevated in many inpatients with COVID-19, although negative value may still be helpful).
- To determine the optimal total duration of prophylactic anticoagulation.
- To determine the optimal dose of prophylactic anticoagulation in specific populations (e.g. those with obesity or advanced kidney disease).
- To determine if routine use of higher doses of anticoagulants (i.e. higher than prophylactic doses as described in the international guidelines), confer net benefit (monitoring anti-Xa activity is an option).