All patients hospitalised with COVID-19 should be given thromboprophylaxis unless they have contraindications to help combat the ‘sticky blood’ phenomenon seen in those with the most severe disease, guidance from the International Society on Thrombosis and Haemostasis (ISTH) has advised.
Clinicians should move to a “universal” strategy for preventing blood clots due to the high rates of venous thromboembolism (VTE) seen in data of patients admitted with severe COVID-19 infection, an expert panel has said.
Early data suggests not only do COVID-19 patients in intensive care have three to six times the risk of deep vein thrombosis than patients with other conditions they also frequently develop microthrombi in the lungs.
The new ISTH guidance states that in patients hospitalised but not needing intensive care, a standard dose of thromboprophylaxis preferably low molecular weight heparin (LMWH) should be given.
The most severely ill patients who need intensive care support should also receive routine thromboprophylaxis after assessment of bleed risk and higher doses may be needed in those at greatest risk.
Multi-modal thromboprophylaxis with mechanical methods such as intermittent pneumonic compression devices should be considered, the guidelines published in the Journal of Thrombosis and Haemostasis state.
After discharge, extended thromboprophylaxis should be considered for all COVID-19 patients that meet high-risk criteria for VTE for 14 days up to a maximum of 30 days.
For those with confirmed VTE existing treatment guidance should be followed, the ISTH recommendations said.
And changing an anticoagulant regimen from a prophylactic to a treatment-dose can be considered in patients without established VTE but deteriorating pulmonary status or ARDS.
It is not yet clear whether changes the impact on haemostasis seen in COVID-19 patients is a direct consequence of the virus or a result of a systemic inflammatory response syndrome seen as a result of a cytokine storm.
The expert panel who put the guidance together stressed the guidance may change as data improves but said the recommendations are sufficiently supported to be adopted into practice.
Guideline author Professor Beverley Hunt, consultant in thrombosis and haemostasis at Guy’s and St Thomas’ NHS Foundation Trust said UK clinicians were seeing high rates of clots in patients even when they are on standard doses of blood thinners.
“These patients seem to need larger doses than other sick patients. We need to know the best doses going forward.”
Results from the UK REMAP-CAP trial which is evaluating therapeutic anticoagulation alongside other treatments for COVID-19 will help provide answers, she added.