Severe Stenosis of the Distal M1 Segment Presenting with Repeated Transient Ischemic Events Despite Dual Antiplatelet and Statin Therapy in a Young Patient: Balloon Angioplasty Followed by Self-Expanding Stent Placement with Excellent Clinical and Angiographic Results

Although embolism is the predominant mechanism affecting the middle cerebral artery (MCA), primary atherosclerosis plays a significant role in MCA occlusive disease, especially in African Americans and Asians. Many patients with this disease have recurrent cerebral ischemic events despite standard medical therapy with antiplatelet agents or oral anticoagulants. In the Extracranial/Intracranial Bypass Trial, patients with symptomatic MCA stenosis randomized to medical therapy had annual ipsilateral stroke rates of 7.8% and total stroke rates of 9.5%. Only about one-third of patients had a warning transient ischemic attack (TIA) before the stroke. The most common presentation was a stroke without a warning TIA. This 28-year-old man presented with an unremarkable medical past, no known vascular risk factors, and no recent history of fever or recent viral infections. Blood tests, including coagulation and serologic studies, were unremarkable. His blood pressure was 120/80 mmHg, and cardiovascular evaluations were normal. He consulted a vascular neurologist after experiencing unusual left-sided headaches and three episodes of transient right hand weakness, and subtle motor speech alterations during the previous 2 weeks. Brain MRI showed cortical-subcortical ischemic lesions in the left parietal lobe. MRA showed severe stenosis of the distal M1 segment of the left MCA. 3T MR vessel wall imaging showed enhancing eccentric wall thickening, raising the diagnosis of active atherosclerotic plaque. Diagnostic angiography confirmed near-total occlusion of the distal left M1 segment of the left MCA. The stenotic process was tapered and proximal to the origin of a frontal cortical branch. The stenosis was hemodynamically significant and caused parenchymographic delay. The left vertebral artery (VA) angiogram showed the development of leptomeningeal posterior cerebral-to-middle cerebral collateral supply to the left temporal lobe. The patient was started on aspirin, clopidogrel, and atorvastatin. Platelet aggregation testing with VerifyNow (Accriva) showed a PRU of 154 (P2Y12). Six weeks after taking these medications, the patient was readmitted for another TIA. However, a new MRI did not show new parenchymal ischemic lesions. Clopidogrel was replaced by prasugrel, and the VerifyNow test result was now PRU 42. Under general anesthesia, we proceeded with balloon angioplasty of the stenotic lesion. The angioplasty caused a dissection of the plaque and clot formation. Re-angioplasty was performed, followed by the implantation of a self-expanding stent with excellent revascularization of the artery and normalization of the hemispheric arteriovenous transit. The patient had an uncomplicated subsequent hospital course with a remarkably rapid and complete reversal of his symptoms. This chapter presents the angioplasty and self-expanding stent revascularization strategy for intracranial atherosclerotic stenoses, its rationale, and its limitations.