Treatment of ChAdOx1 nCoV-19 Vaccine-Induced Immune Thrombotic Thrombocytopenia Related Acute Ischemic Stroke

Abstract

Recently cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) and thrombosis following the adenoviral vector vaccine against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported. A mechanism similar to heparin-induced thrombocytopenia was proposed with antibodies to platelet factor 4 (PF4). Vaccine related arterial thrombosis in the brain is rare but life-threatening and optimal treatment is not established. We report clinical, laboratory, imaging findings and treatment in a 51-year-old female presenting with acute left middle cerebral artery (MCA) occlusion 7 days after the first dose of ChAdOx1 nCoV-19 vaccine. Due to low platelet count and suspicion of VITT she was not eligible for intravenous thrombolysis (IVT) and proceeded to mechanical thrombectomy (MER) with successful recanalization four hours after onset of symptoms. Treatment with intravenous immunoglobulin (IVIG) and heparin pentasaccharide fondaparinux was initiated. Presence of anti-PF4 antibodies was confirmed. The patient improved clinically with normalization of platelet count. Clinicians should be alert of VITT in patients with acute ischemic stroke after ChAdOx1 nCov-19 vaccination and low platelet counts. MER showed to be feasible and effective. We propose considering MER in patients with VITT and large vessel occlusion despite thrombocytopenia. High-dose IVIG should be started immediately. Alternative anticoagulation to heparin should be started 24 hours after stroke onset unless significant hemorrhagic transformation occurred. Platelet transfusion is contraindicated and should be considered only in severe hemorrhagic complications. Restenosis or reocclusion of the revascularized artery is possible due to the hypercoagulable state in VITT and angiographic surveillance after the procedure is reasonable.

Keywords: Mechanical thrombectomy; Stroke; Thrombocytopenia; VITT.

Fig. 1

Head CT and CT perfusion – TTP (time to peak) and CBV (cerebral blood volume); CTA – left M1 occlusion and chronic left ICA dissection with pseudoaneurysm.

Fig. 2

Digital subtraction angiography – left M1 segment occlusion; recanalisation of left M1 segment; chronic left ICA dissection with pseudoaneurysm.

Fig. 3

Head CT 24 hours after MER – small area of MCA territory infarction with mild hemorrhagic transformation. Surveillance head MRI on day 10, nine days after fondaparinoux was started (fluid attenuated inversion recovery – FLAIR and susceptibility weighted imaging – SWI sequence) shows no progression of hemorrhagic transformation.

Fig. 4

CTA performed on day 11 shows 80–90% restenosis of left M1 segment and subsequent resolution of stenosis on CTA performed on day 18, 17 days after introducing anticoagulant treatment.