I. M. Pignat 1, V. Mendes Pereira 2, F. Perren 1
1 HUG, University Hospital and Medical Faculty of Geneva, Department of Neurology, Neurosonology Unit – Geneva,
2 HUG, University Hospital and Medical Faculty of Geneva, Department of Radiology, Interventional Neuroradiology Unit – Geneva, Switzerland
Objective: Stent retrievers are new devices that can be also used to perform mechanical intracranial thrombectomy. They have revolutionized endovascular treatment of acute ischemic stroke with good recanalization and acceptable safety. However, previous animal studies have shown that mechanical thrombectomy may cause endothelial injury of the arterial wall leading to myointimal hyperplasia.
Material and Methods: Acute ischemic stroke patients suffering from acute intracranial single large artery occlusion in which mechanical thrombectomy using stent retrievers was performed were studied. Only those with complete vessel recanalization as assessed by post-procedural DSA and in whom MRA and transcranial duplex sonography (TDS) were performed were retained. Complete revascularization was defined as modified TICI 2b or 3. Patients treated with intra-arterial thrombolysis or stenting of these arteries were excluded.
Results: 20 acute ischemic stroke patients (10 women; mean age 63.7 years) due to arterial occlusion (19MCA;1BA) showed complete recanalization post thrombectomy. All of them received acetylsalicylic acid. DSA post thrombectomy and post acute MRA confirmed complete recanalization without residual stenosis or vasospasm. However, in 18/20 patients TDS (mean 3.8 days after thrombectomy) showed segmental acceleration of blood flow velocities in the affected segments of these arteries (MCA PSVmax at least > 35% as compared at same depth with the controlateral side; BA PSVmax > 40% as compared to velocities measured in the same vessel). None of them showed clinical deterioration.
Discussion: This pilot study is the first showing with transcranial duplex sonography early very focal acceleration of blood flow velocities in intracranial arteries after thrombectomy with stent retrievers. In the absence of residual stenosis or vasospasms, this might be a sign of vessel wall i.e. intimal injury in humans. Whether this is due to local inflammatory agents, neothrombosis or myointimal hyperplasia is not yet clear.
Key words: acute ischemic stroke, stent retrievers, thrombectomy, transcranial duplex ultrasound.