Fabrication of Shape Memory Polymer Endovascular Thrombectomy Device for Treating Ischemic Stroke.

Abstract

Stroke is the second result for death and ischemic stroke constitutes most of all stroke cases. Ischemic stroke takes place when blood clot or embolus blocks cerebral vessel and interrupts blood flow, which often leads to brain damage, permanent disability, or death. There is a 4.5-hour (golden hour) treatment window to restore blood flow prior to permanent neurological impairment results. Current treatments of stroke consist mechanical system or thrombolytic drug therapy to disrupt or dissolve thrombus. Thrombolytics given more than 4.5 h after initial onset of symptoms are not effective on all thrombi. Also, the drugs may cause intracranial hemorrhage, which may be severe or fatal. New treatment modality should improve mortality rates and decrease morbidity. An effective treatment method should be easy, fast to deploy and resolve thrombus faster than current therapies. Promising method for treatment of stroke is mechanical retrieving of thrombi employing device deployed endovascularly. Advent of smart materials has led to research fabrication of several minimally invasive endovascular devices that take advantage of new materials capabilities. One of these capabilities is shape memory, is capability of material to store temporary form, then activate to primary shape as subjected to stimuli. Shape memory polymers (SMPs) have been employed as good materials for thrombectomy device fabrication. Therefore, current review presents thrombectomy device development with SMPs and fabrication of SMP-based devices for improving stroke treatment is also described. Design, performance, limitations, and in vitro or in vivo clinical results of SMP-based thrombectomy devices are identified. Furthermore, future directions of SMP-based thrombectomy devices are highlighted. Review also sheds light on SMP's future outlook and recommendations for thrombectomy device application, opening a new era for advanced materials in materials science. This will demonstrate how new approaches can be achieved employing the latest trends in research world in the development of advanced SMP materials. This article is protected by copyright. All rights reserved.