Ispitivanje upotrebljivosti stentova promjenjivih promjera izrađenih od polimera s memorijom oblika

master's thesis

• Title (english): Feasibility analysis of shape memory polymer stents with variable diameter
• Author: Ana Marija Šegon
• Mentor: Lana Virag (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-07-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Ateroskleroza je jedna od najčešćih kardiovaskularnih bolesti, a tijekom njezinog razvoja dolazi do zadebljanja i oštećenja stijenke krvnih žila stvaranjem različitih aterosklerotskih promjena, najčešće plaka. Liječenje se može provesti kirurškim ili endovaskularnim pristupom. Endovaskularni pristup često uključuje ugradnju stenta. Stentovi se, prema načinu ugradnje, dijele na one koje se šire balonom (npr. metalni stentovi) i samoekspandirajuće (izrađeni od legura ili polimera s memorijom oblika). Samoekspandirajući stentovi uzrokuju manje oštećenja stijenke prilikom ugradnje, ali je s druge strane poznato da polimerni stentovi imaju lošija mehanička svojstva od metalnih. Međutim, razvoj novih i unapređenje postojećih materijala i tehnologija izrade omogućuje izradu složenijih geometrija stentova, pa tako i prilagođavanje oblika stenta svakom pacijentu posebno. Primjerice, da bi se osigurala dovoljna radijalna čvrstoća polimernog stenta, moguće je izraditi stent koji ima promjenjiv promjer, umjesto često korištene ravne mrežaste cjevčice.
U sklopu ovog diplomskog rada definirana je pojednostavljena geometrija karotide s aterosklerotskim plakom kako bi se procijenila upotrebljivost stentova izrađenih od polimera s memorijom oblika i promjenjivim promjerom stenta. Razvijen je numerički postupak ugradnje stenta u karotidnu arteriju, koristeći hiperelastične modele za opisivanje materijala stijenke i stenta. Analizirana je upotrebljivost stentova s promjenjivim promjerom koristeći naprezanja u stentu kao kriterij, te je ocijenjena učinkovitost predloženih stentova s obzirom na smanjenje stenoze nakon ugradnje.

Abstract (english)

Atherosclerosis is one of the most common cardiovascular diseases, characterized by thickening and damage to the blood vessel walls due to the formation of various atherosclerotic changes, most commonly plaques. Treatment can be performed through surgical or endovascular approaches. The endovascular approach often involves the implantation of a stent. Stents are divided based on the method of implantation, into those that expand with a balloon (e.g., metal stents) and self-expanding stents (made of shape memory alloys or polymers). Self-expanding stents cause less damage to the vessel wall during implantation, but it is known that polymer stents have inferior mechanical properties compared to metal stents. However, the development of new and improved materials and manufacturing technologies allows for the production of more complex stent geometries, including customized stent shapes for individual patients. For example, to ensure sufficient radial strength of a polymer stent, it is possible to create a stent with a variable diameter instead of the commonly used straight mesh tube.
In this thesis, a simplified geometry of the carotid artery with an atherosclerotic plaque was defined to assess the usability of shape memory polymer stents with a variable diameter. A numerical procedure for stent implantation in the carotid artery was developed using hyperelastic models to describe the material behavior of the vessel wall and stent. The usability of stents with a variable diameter was analyzed using stress in the stent as a criterion, and the effectiveness of the proposed stents in reducing stenosis after implantation was evaluated.

• Keywords: numerička analiza; stent; stenoza; hiperelastični materijal
• Keywords (english): numerical analysis; stent; stenosis; hyperelastic material
• Language: croatian
• URN:NBN: urn:nbn:hr:235:643621
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechatronics and Robotics, Autonomous Systems; Course: Engineering Modelling and Computer Simulation; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-07-13 12:37:04