Enhancing clot composition analysis in acute ischemic stroke with non-contrast spectral CT: A phantom-based study.

Acute ischemic stroke (AIS), caused by blood flow obstruction due to a clot, is a leading medical emergency, with mechanical thrombectomy (MT) being the standard of care intervention. The success of MT partly depends on the ability to effectively assess clot composition, as different clot types (e.g.

Impact of histological clot composition on preprocedure imaging and mechanical thrombectomy.

Introduction: We studied the relationship of acute ischemic stroke (AIS) large-vessel occlusion clot composition with vessel recanalization and preprocedure imaging.

Subjects And Methods: Individual clots from AIS patients who underwent mechanical thrombectomy (MT) between September 2016 and September 2018 were examined. Clot composition was analyzed histologically through a trichrome staining and image segmentation, and the area occupied by red blood cells (RBCs), fibrin, or mixed composition was quantified.

Quantitative Characterization of Recanalization and Distal Emboli with a Novel Thrombectomy Device.

Purpose: The first-pass effect during mechanical thrombectomy improves clinical outcomes regardless of first-line treatment approach, but current success rates for complete clot capture with one attempt are still less than 40%. We hypothesize that the ThrombX retriever (ThrombX Medical Inc.) can better engage challenging clot models during retrieval throughout tortuous vasculature in comparison with a standard stent retriever without increasing distal emboli.

Mechanical behavior of in vitro blood clots and the implications for acute ischemic stroke treatment.

Background: Clot mechanical properties are influenced by composition and the arrangement of components within the clot. This work investigates the effects of platelet-driven contraction on blood clot microstructure and mechanical behavior, and provides insight into some implications for mechanical thrombectomy.

Methods: Platelet-contracted clot analogues (PCCs) and non-contracted clot analogues (NCCs) were prepared from blood mixtures of various hematocrits (%H), that is, the volume percentage of red blood cells (RBCs) in the mixture.

Role of Balloon Guide Catheter in Modern Endovascular Thrombectomy.

Proximal flow control achieved with a balloon guide catheter (BGC) during endovascular treatment of acute ischemic stroke is reviewed in this article. In clinical practice, BGCs offer a multi-faceted approach for clot retrieval by creating proximal flow arrest, reducing embolic burden, and shortening procedure time. Evaluation of frontline thrombectomy procedures with BGCs revealed advantages of combined use over the conventional guide catheter (CGC), notably in the significant reduction of distal emboli to both the affected and previously unaffected territories.

Platelet-Rich Emboli in Cerebral Large Vessel Occlusion Are Associated With a Large Artery Atherosclerosis Source.

Background and Purpose- Nearly 30% of large vessel occlusion acute ischemic stroke clots are from an unknown source. We assessed histological clot composition in a series of patients with large vessel occlusion and investigated correlations between clot composition and stroke pathogenesis. Methods- As part of the multi-institutional STRIP registry (Stroke Thromboembolism Registry of Imaging and Pathology), consecutive emboli retrieved during mechanical thrombectomy were stained using Martius Scarlett Blue and analyzed using machine learning software.

A canine model of mechanical thrombectomy in stroke.

Purpose: To develop a preclinical model of stroke with a large vessel occlusion treated with mechanical thrombectomy.

Materials And Methods: An ischemic stroke model was created in dogs by the introduction of an autologous clot into the middle cerebral artery (MCA). A microcatheter was navigated to the clot and a stent retriever thrombectomy was performed with the goal to achieve Thrombolysis in Cerebral Ischemia (TICI) 2b/3 reperfusion.

Platelet-rich clots as identified by Martius Scarlet Blue staining are isodense on NCCT.

Background: Current studies on clot characterization in acute ischemic stroke focus on fibrin and red blood cell composition. Few studies have examined platelet composition in acute ischemic stroke clots. We characterize clot composition using the Martius Scarlet Blue stain and assess associations between platelet density and CT density.

Complete clot ingestion with cyclical ADAPT increases first-pass recanalization and reduces distal embolization.

Background: Evidence is mounting that first-pass complete recanalization during mechanical thrombectomy is associated with better clinical outcomes in patients presenting with an emergent large vessel occlusion. We hypothesize that aspiration achieving complete clot ingestion results in higher first-pass successful recanalization with quantitative reduction in distal emboli.

Methods: A patient-specific cerebrovascular replica was connected to a flow loop.

Microcatheter navigation through the clot: does size matter?

Background: Despite high recanalization rates achieved with endovascular treatment of acute ischemic strokes, around 50% of eligible patients will not achieve a good outcome. Parameters that may determine patient outcomes include: time from puncture to recanalization, the collateral status, the anesthesia regimen, blood pressure management, and distal emboli. Characterization of distal emboli generated during mechanical thrombectomy has been performed in previous studies.

Novel Distal Emboli Protection Technology: The EmboTrap.

Background: Over the course of the thrombectomy procedure, clot fragments may become dislodged and lead to downstream emboli due to manipulation of an endovascular device. The EmboTrap thrombectomy system features an inner stent channel with an outer stent trap design that may potentially reduce the risk of distal clot fragmentation during clot removal. We tested the hypothesis that distal emboli to both the same and new territory generated during mechanical thrombectomy are a function of device design.

Development of a high resolution MRI intracranial atherosclerosis imaging phantom.

Background And Purpose: Currently, there is neither a standard protocol for vessel wall MR imaging of intracranial atherosclerotic disease (ICAD) nor a gold standard phantom to compare MR sequences. In this study, a plaque phantom is developed and characterized that provides a platform for establishing a uniform imaging approach for ICAD.

Materials And Methods: A patient specific injection mold was 3D printed to construct a geometrically accurate ICAD phantom.

An in vitro evaluation of distal emboli following Lazarus Cover-assisted stent retriever thrombectomy.

Background: Formation of clot fragments during mechanical thrombectomy for acute ischemic stroke can occlude the distal vasculature, which may reduce the rate of good clinical outcome.

Objective: To examine the hypothesis that distal embolization can be reduced using stent retriever thrombectomy in combination with Lazarus Cover technology.

Methods: Hard, fragment-prone clots were used to create middle cerebral artery occlusions in a vascular phantom.

Quantitative assessment of device-clot interaction for stent retriever thrombectomy.

Purpose: Rapid revascularization in emergent large vessel occlusion with endovascular embolectomy has proven clinical benefit. We sought to measure device-clot interaction as a potential mechanism for efficient embolectomy.

Methods: Two different radiopaque clot models were injected to create a middle cerebral artery occlusion in a patient-specific vascular phantom.

Shear-Activated Nanoparticle Aggregates Combined With Temporary Endovascular Bypass to Treat Large Vessel Occlusion.

Background And Purpose: The goal of this study is to combine temporary endovascular bypass (TEB) with a novel shear-activated nanotherapeutic (SA-NT) that releases recombinant tissue-type plasminogen activator (r-tPA) when exposed to high levels of hemodynamic stress and to determine if this approach can be used to concentrate r-tPA at occlusion sites based on high shear stresses created by stent placement.

Methods: A rabbit model of carotid vessel occlusion was used to test the hypothesis that SA-NT treatment coupled with TEB provides high recanalization rates while reducing vascular injury. We evaluated angiographic recanalization with TEB alone, intra-arterial delivery of soluble r-tPA alone, or TEB combined with 2 doses of intra-arterial infusion of either the SA-NT or soluble r-tPA.

Imaging Inflammation in Cerebrovascular Disease.

Imaging inflammation in large intracranial artery pathology may play an important role in the diagnosis of and risk stratification for a variety of cerebrovascular diseases. Looking beyond the lumen has already generated widespread excitement in the stroke community, and the potential to unveil molecular processes in the vessel wall is a natural evolution to develop a more comprehensive understanding of the pathogenesis of diseases, such as ICAD and brain aneurysms.

Risk of distal embolization with stent retriever thrombectomy and ADAPT.

Background: There is a discrepancy in clinical outcomes and the achieved recanalization rates with stent retrievers in the endovascular treatment of ischemic stroke. It is our hypothesis that procedural release of embolic particulate may be one contributor to poor outcomes and is a modifiable risk. The goal of this study is to assess various treatment strategies that reduce the risk of distal emboli.

Aneurysm permeability following coil embolization: packing density and coil distribution.

Background: Rates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability.

Methods: Aneurysm models were coiled using either Guglielmi detachable coils or Target coils.

Endovascular treatment of tandem vascular occlusions in acute ischemic stroke.

Background And Purpose: Tandem vascular occlusions are an important cause of acute ischemic stroke (AIS) and present unique treatment challenges. We report our experience of managing a subset of AIS patients with extracranial vascular stenting/angioplasty and intracranial revascularization.

Methods: Consecutive patients who presented at three centers with AIS from tandem vascular occlusions confirmed by brain and neck CT imaging were included in the study.

Early detachment of the Solitaire stent during thrombectomy retrieval: an in vitro investigation.

Objective: To elucidate the early detachment of the Solitaire stent during mechanical thrombectomy, we tested the stent in vitro under various conditions and evaluated with microscopy.

Methods: A total of five stents were tested. Using a dynamic mechanical analysis machine, we calculated the tensile force needed for separation of the four stents from the pusher wire.

Clot injection technique affects thrombolytic efficacy in a rat embolic stroke model: implications for translaboratory collaborations.

Current recommendations encourage the use of embolic stroke (ES) models and replication of results across laboratories in preclinical research. Since such endeavors employ different surgeons, we sought to ascertain the impact of injection technique on outcome and response to thrombolysis in an ES model. Embolic stroke was induced in Male Wistar Kyoto rats (n=166) by a fast or a slow clot injection (CI) technique.

Reduction in distal emboli with proximal flow control during mechanical thrombectomy: a quantitative in vitro study.

Background And Purpose: To evaluate the impact of proximal flow control on efficacy and safety of mechanical thrombectomy in an in vitro middle cerebral artery occlusion.

Methods: Three independent variables, including clot type, device (Merci Retriever, Solitaire FR, and Trevo devices), and use of a balloon guide catheter, were used to ascertain the impact of proximal flow control on the size and number of distal emboli generated during thrombectomy. Secondary end points were the recanalization rate and amount of flow restored.