A Case of Delayed-Onset Stent-Induced Dissection of the Internal Carotid Artery After Stenting for Near-Occlusion.

Internal carotid artery near-occlusion (ICANO) is characterized by severe internal carotid artery (ICA) stenosis with distal collapse. Although carotid artery stenting (CAS) is a treatment option, its efficacy and the associated complications remain controversial. Herein, we report a case of ICANO treated with CAS complicated by delayed occlusive dissection at the distal stent edge, which was successfully managed with additional stenting. A 52-year-old man with hypertension, depression, and heavy smoking was referred for low left ICA signal intensity on magnetic resonance angiography (MRA). Carotid ultrasound and computed tomography angiography (CTA) confirmed severe stenosis with distal vessel collapse. Digital subtraction angiography (DSA) showed a delayed flow and collateral circulation through the anterior and posterior communicating arteries. The patient was diagnosed with asymptomatic ICANO and underwent CAS to prevent stroke. An open-cell stent was then deployed. While postprocedural imaging confirmed ICA patency, full vessel expansion was not achieved, leading to a diameter mismatch at the distal stent edge. The patient initially remained asymptomatic; however, mild posterior neck pain occurred on postoperative day 4. On day 5, carotid ultrasonography revealed an ICA occlusion. Urgent CTA and MRA revealed poor ICA visualization, and three-dimensional T1-weighted imaging (3D T1-volume isotropic turbo spin-echo acquisition (VISTA)) revealed a dissection flap extending to the proximal petrous ICA, causing severe stenosis. Urgent DSA confirmed a severely delayed contrast flow immediately distal to the stent. Endovascular treatment with closed-cell stents successfully restored ICA patency. The patient was discharged without neurological deficits or neck pain, and follow-up imaging confirmed sustained vessel patency. This case highlights that delayed arterial dissection is a rare but serious complication of CAS in patients with ICANO and vessel collapse. Stent selection and vessel diameter mismatch may contribute to intimal injury, which requires careful procedural planning.