Clot composition and recanalization outcomes in mechanical thrombectomy.

Background: Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

Transvenous embolization of cerebrospinal fluid-venous fistulas: Independent validation and feasibility of upper-extremity approach and using dual-microcatheter and balloon pressure cooker technique.

Background: Transvenous embolization is emerging as a promising treatment for cerebrospinal fluid-venous fistulas (CVF) associated with spontaneous intracranial hypotension (SIH).

Objective: To perform an independent validation of the efficacy and safety of the procedure and describe the procedural techniques used at our institution.

Methods: A retrospective review was performed including consecutive patients with SIH who had undergone CVF embolization with 3-month clinical and imaging follow-up.

Aneurysm healing after endovascular treatment in the Helsinki sidewall aneurysm model: a systematic review.

Aims: Intracranial aneurysms are treated with a variety of endovascular devices including coils, stents, and flow diverters. The mechanisms by which these devices result in aneurysm occlusion and subsequent healing have been the subject of significant research using various animal models. The murine Helsinki aneurysm model is a sidewall aneurysm created by the end-to-side anastomosis of a donor aortic graft onto the abdominal aorta of a recipient animal.

Evaluation of an in vivo preclinical model for human middle meningeal artery embolization using the posterior intercostal artery of the swine.

Background: Embolization of the middle meningeal artery (MMA) is a promising minimally invasive technique that is gaining traction in the treatment of chronic subdural hematoma. Unfortunately, the human meninges and associated arteries are significantly larger than those of conventional laboratory animals, making the development of a clinically relevant animal model for testing of embolization agents elusive.

Objective: To introduce the posterior intercostal artery (PIA) model in swine and provide anatomical, angiographic, histological, and procedural data to validate its relevance in modeling the human MMA.

Bioresorbable flow diverters for the treatment of intracranial aneurysms: review of current literature and future directions.

The use of flow diverters is a rapidly growing endovascular approach for the treatment of intracranial aneurysms. All FDA-approved flow diverters are composed of nitinol or cobalt-chromium, which will remain in the patient for the duration of their life. Bioresorbable flow diverters have been proposed by several independent investigators as the next generation of flow diverting devices.

Human "live cadaver" neurovascular model for proximal and distal mechanical thrombectomy in stroke.

Background: Preclinical testing platforms that accurately replicate complex human cerebral vasculature are critical to advance neurointerventional knowledge, tools, and techniques. Here, we introduced and validated a human "live cadaveric" head-and-neck neurovascular model optimized for proximal and distal vascular occlusion and recanalization techniques.

Methods: Human cadaveric head-and-neck specimens were cannulated bilaterally in the jugular veins, carotid, and vertebral arteries.

Quantification of clot spatial heterogeneity and its impact on thrombectomy.

Background: Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

Failure modes and effects analysis of mechanical thrombectomy for stroke discovered in human brains.

Objective: Despite advancement of thrombectomy technologies for large-vessel occlusion (LVO) stroke and increased user experience, complete recanalization rates linger around 50%, and one-third of patients who have undergone successful recanalization still experience poor neurological outcomes. To enhance the understanding of the biomechanics and failure modes, the authors conducted an experimental analysis of the interaction of emboli/artery/devices in the first human brain test platform for LVO stroke described to date.

Methods: In 12 fresh human brains, 105 LVOs were recreated by embolizing engineered emboli analogs and recanalization was attempted using aspiration catheters and/or stent retrievers.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy.

Background: Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective: To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Preclinical testing platforms for mechanical thrombectomy in stroke: a review on phantoms, in-vivo animal, and cadaveric models.

Preclinical testing platforms have been instrumental in the research and development of thrombectomy devices. However, there is no single model which fully captures the complexity of cerebrovascular anatomy, physiology, and the dynamic artery-clot-device interaction. This article provides a critical review of phantoms, in-vivo animal, and human cadaveric models used for thrombectomy testing and provides insights into the strengths and limitations of each platform.

Systematic review and meta-analysis of current rates of first pass effect by thrombectomy technique and associations with clinical outcomes.

Background: First pass effect (FPE) in mechanical thrombectomy is thought to be associated with good clinical outcomes.

Objective: To determine FPE rates as a function of thrombectomy technique and to compare clinical outcomes between patients with and without FPE.

Methods: In July 2020, a literature search on FPE (defined as modified Thrombolysis in Cerebral Infarction (TICI) 2c-3 after a single pass) and modified FPE (mFPE, defined as TICI 2b-3 after a single pass) and mechanical thrombectomy for stroke was performed.