A Case of Internal Carotid Artery Restenosis Due to Neointimal Hyperplasia Following Balloon Angioplasty

Objective: The causes of restenosis following balloon angioplasty are reported to be vasospasm, thrombosis, and recurrence of atherosclerosis. We report a case of internal carotid artery (ICA) occlusion treated by emergency endovascular renacalization and carotid endarterectomy (CEA) for the restenosis, which revealed that the cause of restenosis was neointimal hyperplasia.Case Presentation: A 70-year-old man was brought to our hospital because of sudden onset left hemiparesis. His National Institute of Health Stroke Scale (NIHSS) score was 13. Magnetic resonance imaging diffusion weighted imaging (MRI DWI) demonstrated hyper-intensity in the right basal ganglia, indicating acute ischemia. Neither the right ICA nor the MCA was visualized on MR angiography. Following intravenous tPA therapy, endovascular treatment was employed. First, the right ICA occlusion was treated by balloon angioplasty and the right M1 occlusion was recanalized by the stent-type thrombus retriever. Complete recanalization was achieved and the patient fully recovered. However, restenosis of the right ICA developed 5 months later and CEA was performed. The postoperative course was uneventful. Based on the pathological examination, the cause of restenosis was migration and proliferation of dedifferentiated smooth muscle (SM) cells, that is, neointimal hyperplasia.Conclusion: Neointimal hyperplasia can be a cause of restenosis following balloon angioplasty.