第七讲第七讲动脉(dòngmài)粥样硬化和高血压AtherosclerosisandHypertension心血管疾病（cardiovasculardisease,CVD）发病率和死亡率居所有疾病之首发病率↑：90年代-200万/年以上2000年-1700万，总死亡人数1/32020年-2500万80%在发展中国家一种与血脂异常及血管壁成分改变有关的动脉疾病，主要累及弹性动脉和较多弹性纤维的肌性动脉，病变特征是血中脂质在动脉内膜沉积，引起内膜灶性纤维性增厚，病灶深部为由坏死组织和细胞外脂质池形成的粥样物质（粥样斑块=纤维帽+脂质核）。动脉粥样硬化（atherosclerosis）Atheroscleroticplaquehas2maincomponents:asoft,lipid-richcoreandahard,collagen-richfibrouscap.Instableplaques,athickfibrouscapmayrepresent>70%ofplaquevolume.Itstabilizestheplaqueandpreventsitfromundergoingrupture.Incontrast,unstableplaquehasathinfibrouscapandisatgreaterriskforrupture.Inunstableplaque,thelipid-richcoremayrepresentthemajorityoftheplaquevolume.Thecoreisrichinextracellularlipids,whichareformedbytrappingblood-derivedlipids,notablylow-densitylipoprotein,orbylipid-filledmacrophages,knownasfoamcells.Theplaquedestabilizesduetoinflammationbyfoamcellsandotherinflammatorymediatorsthatmaketheplaquemorevulnerabletorupture.Thiscommonlyoccursatthejunctionoftheplaqueandthelessdiseasedvesselwall.Asaresult,thelipidcoremaybeexposedtoflowingbloodleadingtoplatelet-mediatedthrombusformation.FalkreviewedtheworkofotherinvestigatorsregardingtheseverityofstenosisanditsassociationwiththeriskofMI.Resultsshowedthat>86%ofMIsresultedfromlesionsthatwere<70%stenosed.MostexpertspriortoFalkthoughtthatpatientshadheartattacksbecauseofblockagesthatincreasedinsizeuntiltheyblockedthebloodvesselandcausedaheartattack.1BasedonthefindingsofFalk,wenowknowtheprimarycauseofaheartattackistheruptureofunstableplaquesthatare<70%stenosedandareclinicallysilent.Approximately200patientsfrom4studieswerestudiedtogeneratetheseresults,whichhavebeenconfirmedinotherstudies.1不稳定斑块（unstableplaque）指脂质核较大、病变偏心、纤维帽较薄、炎症细胞浸润较重、在受到外力作用时容易破裂的斑块，又称脆性斑块（vulnerableplaque）。稳定斑块（stableplaq...
