The British Thoracic Society has published guidance on venous thromboembolic disease in patients with COVID-19.
Emerging data and clinical experience suggest an increased prevalence of venous thromboembolic events (VTE) in COVID-19, especially in patients with more severe disease.
COVID-19 infection is associated with inflammation, disseminated intravascular coagulation, hypoxaemia and immobility, which may all predispose the development of thromboembolic complications, the Society noted.
Abnormalities in coagulation appear to be common and are associated with poorer outcomes.
Clinicians should thus suspect VTE if sudden worsening of hypoxaemia, blood pressure or tachycardia occurs, or if clinical signs suggestive of deep vein thrombosis develop in patients with COVID-19.
As VTE appears to be especially common in patients requiring critical care management, there should be a particularly high index of suspicion and a low threshold for investigating/treating VTE in this cohort, the Society noted.
Diagnosing VTE may be more complex in patients with COVID-19 due to several factors:
- clinical state making movement to radiology departments difficult;
- local protocols regarding radiological investigations in patients with known COVID-19; and
- overrun radiological services due to very high numbers of hospitalised COVID-19 patients.
While stating clinical trials of the use of higher intensity low-molecular-weight heparin (LMWH) thromboprophylaxis in patients with COVID-19 are needed to better guide risk stratification and clinical management, the Society suggested the following possible approach:
- Standard-risk patient: standard prophylactic dose LMWH (e.g., for a 70 kg patient with creatinine clearance (CrCl) >30 mL/min: dalteparin 5000 units od, enoxaparin 40 mg od).
- High-risk patient: intermediate dose LMWH (e.g., for a 70 kg patient with CrCl >30 mL/min: dalteparin 5000 units bd, enoxaparin 40 mg bd).
- Proven or suspected acute VTE: therapeutic dose LMWH (bd dosing may be preferred in critical care patients who may require invasive procedures or if bleeding risk felt to be elevated). Duration of treatment would generally be three months due to the strong provoking factor.