An elderly case with late carotid stent thrombosis: possible role of antiphospholipid antibodies

The case study speculates that the antiphospholipid antibodies acquired during the follow-up period of carotid artery stenting may cause late stent thrombosis that is resistant to direct oral anticoagulants. A 73-year-old man was hospitalized with complaints of weakness in the right lower extremity. The patient had undergone carotid artery stenting for symptomatic stenosis of the left internal carotid artery 6 years prior and had received antiplatelet therapy with clopidogrel 75 mg/day. As the patient had developed atrial fibrillation without stent stenosis at the age of 70 years, anticoagulation therapy with rivaroxaban15 mg/day was initiated while discontinuing clopidogrel. On admission, diffusion weighted imaging (DWI) revealed acute brain infarcts in the territory of the left middle cerebral artery. Contrast-enhanced computed tomography and cerebral angiography exposed severe stenosis in the left carotid artery accompanied by a filling defect caused by a floating thrombus. Laboratory examination revealed the presence of three types of antiphospholipid antibodies, with marked prolongation of activated partial thromboplastin time (APTT). Replacement of rivaroxaban with warfarin eliminated the thrombus without recurrent stroke. In conclusion, late stent thrombosis may be associated with antiphospholipid antibodies acquired during the follow-up period of carotid artery stenting.