Date of Graduation

5-2018

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering (MSBME)

Degree Level

Graduate

Department

Biomedical Engineering

Advisor/Mentor

Hestekin, Jamie A.

Committee Member

Jensen, Morten O.

Second Committee Member

Jensen, Hanna A.

Third Committee Member

Balachandran, Kartik

Keywords

Stroke; Treatment; Acute ischemic event; Emboli analog formation; In-vitro model

Abstract

Stroke is the leading cause of disability and a primary cause of mortality, resulting in an estimated $33 billion dollars spent on healthcare, rehabilitation and lost productivity in the United States each year. The most prevalent cause of stroke incidents are acute ischemic events, manifested as blood clots in the vasculature supplying the brain. Current gold standard treatments have improved since 2006 with the introduction of mechanical stent retrievers; however, several issues with the current treatments to acute ischemic stroke remain. Thrombolysis of the clot with a tissue plasminogen activator may lead to weakening the vessel wall and consequently, hemorrhaging. Mechanical thrombectomy may result in clot fragmentation causing embolization downstream in a subsequent vessel. The proposed methodologies for emboli analog (EA) formation and in-vitro model for AIS simulation offer platforms for continued development of retrieval mechanism prototypes. EAs were developed in static and dynamic environments to compare composition and mechanical properties with cerebral thromboemboli mechanical and physiological properties. EAs formed at 50 RPM with a vertical rotator were found to be most similar in material stiffness to thromboemboli extracted from carotid endarterectomy (CEA) procedures (p=0.972). These EAs were also fibrin-rich, which clinical studies have found that fibrin-rich thromboemboli are linked to lower recanalization rates. Although the static EAs were not significantly different in material stiffness from CEA thromboemboli, they are homogenously composed of RBCs. An in-vitro model was created to simulate AIS physiological parameters including flow rate, temperature and vessel dimensions for prototype testing as well. A model of the vasculature was created using additive manufacturing and silicone to mimic cerebral vasculature including the middle cerebral artery, internal carotid artery and basilar artery where the majority of strokes occur.

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