Optical Coherence Tomography Imaging in Acute Ischemic Stroke: Preliminary Animal and Human Results

Abstract

Abstract INTRODUCTION Studies evaluating endothelial injury after endovascular thrombectomy (EVT) have been done by means of retrieved human thrombus, magnetic resonance (MR) vessel-wall imaging, and animal histopathologic studies. These techniques have limitations, as MR imaging has insufficient spatial resolution to directly visualize endothelium, and histopathologic examinations are ex vivo and unable to provide real-time patterns of injury. The aim of the current study is intraluminal imaging after EVT using optical coherence tomography (OCT). We describe our animal model for thrombus preparation, vessel occlusion, mechanical thrombectomy, and subsequent endovascular OCT imaging. Furthermore, we describe the first human endovascular OCT imaging after EVT in 2 stroke patients. METHODS A total of 3 swine weighing 35 to 40 kg were selected for the animal model. Autologous venous whole blood drawn 48 h before the procedure was used to create thrombus. The bilateral superficial cervical arteries and right internal thoracic artery were used for occlusion given their diameters of 2 to 3 mm and 3 to 4 mm, respectively. A second-generation stent retriever was used for EVT. Thrombi were retrieved after 1, 3, and 6 h with subsequent intraluminal OCT imaging. Next, 2 consecutive patients with basilar artery occlusion underwent EVT and endovascular OCT imaging. RESULTS In the animal model, revascularization and OCT imaging was successful for all 9 vessels. Endothelial injury was observed in 4/9 (44%) of vessels, and residual thrombus was observed in 4/9 (44%) of vessels despite complete revascularization. All vessels undergoing EVT after 6 h had evidence of endothelial injury, and 2/3 (66%) had residual thrombus. Both basilar stroke patients had significant residual thrombus despite complete angiographic revascularization. CONCLUSION Endothelial injury and residual thrombus despite complete revascularization is present after EVT and can be observed in real time using intravascular OCT. It is possible that the longer occlusive thrombus is present, the more endothelial injury will occur during EVT.