不稳定斑块论文：动脉粥样硬化斑块失稳破裂的突变理论研究

不稳定斑块论文：动脉粥样硬化斑块失稳破裂的突变理论研究【中文摘要】动脉粥样硬化斑块的破裂是导致急性心血管事件的触发因素,临床观测研究的结果对动脉粥样硬化斑块的破裂做出了一部分解释,总结了不稳定斑块的特征,但是斑块的破裂机制至今还没有一个完整的模型可以解释。苏海军等从弹性力学稳定性理论出发,利用有矩理论,建立了动脉粥样硬化斑块纤维帽运动的静力学及动力学模型,研究了纤维帽的力学失稳与斑块破裂之间的联系,提出了纤维帽的参数共振导致斑块破裂的新机制,得到与临床结果相一致的结论。本文基于静力学模型,从弹性力学突变理论出发,将斑块纤维帽视为可以承受弯曲力矩的各向同性的均匀的薄壳体,利用弹性力学的能量释放理论和势能驻值原理,建立了描述纤维帽运动的尖点突变模型,在此基础上进一步描述了纤维帽的跳跃性失稳能量释放与斑块破裂之间的联系。全文共分四个章节。第一章为。介绍了动脉粥样硬化的病理学基础,不稳定斑块观点的由来及常见特征,同时回顾了目前斑块破裂的生物力学研究进展及临床上的最新结果,简要介绍了弹性力学突变理论及本文的主要研究方法。第二章视动脉粥样硬化斑块的纤维帽为一个均匀扁平的薄壳体,根据能量守恒原理,建立了描述斑块纤维帽运动变化的能量方程和突变模型。模型结果表明,当纤维帽所承受的压力超过一定的临界值之后,纤维帽将会失稳而产生大的变形,从而诱发斑块破裂。纤维帽发生跳跃时的临界压力qcr的表达式为：根据对qc,的分析，证明了纤维帽具有厚度薄、弹性大、压缩性强的柔软斑块更容易发生破裂。第三章从能量的角度对斑块的稳定性进行了讨论,研究了纤维帽在失稳发生突变时单位体积释放的弹性能与斑块破裂之间的关系。纤维帽发生突变时单位体积释放的弹性能越大,斑块越容易失稳而发生破裂：反之,单位体积释放的弹性能越小,斑块的稳定性越强,即越不容易发生破裂。纤维帽发生突变时单位体积释放的弹性能(?)的表达式为：第四章为总结,阐述了尖点突变模型中斑块破裂的机制和斑块的各个参数对斑块稳定性的影响,同时指出了本文的不足之处及有待解决的问题。【英文摘要】Ruptureofatheroscleroticplaqueisthemaintriggerofacutecardiovascularevents,theresultsbasedontheclinicalresearchexplainedsomefactsoftheruptureofatheroscleroticplaqueandsummarizedsomecharacteristicsofunstableplaque,butthemechanismofplaqueruptureisstillunknown.HaijunSuetconstructedstaticanddynamicmodelstodescribetherelationbetweenthemotionofthefibrouscapandruptureofatheroscleroticplaqueusingthetheoryofelasticmechanics.Theygaveanewmodelthatparameterresonancecouldleadtoatheroscleroticplaquerupture.Theresultsobtainedfromthemodelwereconsistentwiththeclinicalexperiments.Beginningwithcatastrophetheory,thispaperconstructedacuspcatastrophemodelbasedonthestaticmodeltodescribethemotionofthefibrouscap.Inthispaper,assumingthatthefibrouscapoftheplaqueasahomogeneousisotropicandlinearelasticthinshell,andusingtheenergyliberationandtheprincipleofstationarypotentialenergy,wemakeafurtherstudybetweenthemotionofthefibrouscapandruptureofatheroscleroticplaque.Thisarticleiscomposedoffourchapters.Inthefirstchapter,wefirstintroducedthepathologyfoundationofatherosclerosis,theviewpointofthevulnerableplaqueaswellasthecommoncharacteristic.Meanwhile,webrieflyreviewedtheprogressinbiomechanicalstudiesofplaqueruptureandthenewresultsobtainedfromtheclinicresearch,andthenintroducedthecatastrophetheoryandthemainmethodsinthisarticle.Inthesecondchapter,assumingthatthefibrouscapoftheplaqueasahomogeneousisotropicandlinearelasticthinshell,weconstructedenergyequationandcuspcatastrophemodelbasedonthelawofconservationofenergy.Theresultsshowthatthecapwouldlosethestabilityanddeformlargelywhenthepressureofthefibrouscapexceededsomecriticalvalues,whichmayinducetheplaquetorupture.Theminimumcriticalpressureisshownasbelow,Accordingtotheanalysisofqcr,wehaveprovedthattheplaquewouldbemorevulnerablewhenithasaelastic,

compressive,thinandflexiblefibrouscap.Inthethirdchapter,wediscussthestabilityoftheplaquefromthepointofviewofenergyandanalyzetherelationshipbetweentheenergyperunitvolumewhichreleasedbythefibrouscapandruptureofatheroscleroticplaque.Ithasshowedthatthemoreenergyreleasedtheplaquerupturemoreeasily,andthereverseisalsotrue.TheenergyAn/Visshownasbelow,Thefourthchapteristhesummary.Weelaboratethemechanismsofplaqueruptureinthecuspcatastrophemodelanddiscusstheplaquestabilityaffectedbypathsofseveralparameters.Moreover,wealsopointouttheshortcomingsofthisarticleaswellastheproblemshouldbesolved.【关键词】不稳定斑块稳定性突变临界压力弹性能【英文关键词】vulnerableplaquestabilitycatastrophecriticalpressureelasticenergy【目录】动脉粥样硬化斑块失稳破裂的突变理论研究中文摘要6-8ABSTRACT8-9主要符号列表10-11第一章研究背景11-20§1.1动脉粥样硬化的现代概念11-12§1.2不稳定斑块的破裂12-14§1.3生物力学研究进展14-17§1.4初等突变理论简介17-20第二章尖点突变模型20-28§2.1模型的建立20-21§2.2模型的分析2.2模型的分析21-23§2.3结果与讨论23-28第三