2249 First-dose ChAdOx1 vaccination and arterial thrombosis risk

We describe three patients diagnosed with vaccine-induced immune thrombocytopaenia and thrombosis syndrome (VITTs) who presented over a three-month period to a tertiary hospital, all of whom had both arterial and venous thrombosis. Case 1: A 53 year-old female had an acute left internal carotid artery (ICA) thrombus requiring intravenous alteplase and endovascular clot retrieval ten days following her first ChAdOx1 vaccination. Her admission was complicated by lower limb arterial thrombosis and pulmonary emboli. Case 2: A 67 year-old female presented with severe headaches 17 days following her first vaccination, and was found to have extensive cerebral venous sinus thrombosis (CVST) and intracerebral haemorrhage requiring decompressive craniectomy and drainage, and also developed multiple peripheral limb arterial thromboses. Case 3: A 57 year-old female who presented with convulsive status epilepticus after her first ChAdOx1 nCoV-19 vaccination ten days prior. She was found to have extensive clot burden with CVST complicated by haemorrhagic transformation of a venous infarct in addition to a complete left ICA occlusion needing thrombectomy. Similarly, she was found to have pulmonary emboli and arterial and venous limb thromboses. All patients received some combination of intravenous immunoglobulin, methylprednisolone, argatroban and ongoing apixaban or fondaparinux.ConclusionsWhilst venous thrombosis is well recognised in VITTs, we describe that the clinical spectrum can also commonly include arterial thrombosis, in the cerebrovascular and peripheral arterial tree. Furthermore, the presentation of this complication with arterial cerebral ischaemia acutely poses special difficulties in acute management given the degree of thrombocytopaenia as a contraindication for thrombolysis.