動(dòng)脈瘤的認(rèn)識(shí)

認(rèn)識(shí)主動(dòng)脈夾層急診胸痛診斷“TheBigFive”

胸痛的五大致命病因AcutecoronarysyndromeAorticdissectionPulmonaryEmbolismTensionPneumothoraxEsophagealRupture主動(dòng)脈起自主動(dòng)脈環(huán)，沿脊柱偏后，上升部稱升主動(dòng)脈，至右無(wú)名動(dòng)脈分支橫行至鎖骨下動(dòng)脈，稱主動(dòng)脈弓，此后沿脊柱左側(cè)下行稱降主動(dòng)脈，穿過(guò)膈肌進(jìn)入腹部稱腹主動(dòng)脈，直達(dá)左右髂動(dòng)脈分支。主動(dòng)脈弓部重要分支的頭、頸動(dòng)脈供應(yīng)兩上肢及顱腦部的血流，以無(wú)名動(dòng)脈和左鎖骨下動(dòng)脈為標(biāo)志又分為右弓和左弓。降主動(dòng)脈有多個(gè)分支，供應(yīng)脊髓的血液。腹主動(dòng)脈是腹腔許多臟器血供的分支主干，如左右腎動(dòng)脈、肝、脾及腸系膜上動(dòng)脈等定義主動(dòng)脈夾層動(dòng)脈瘤，也有稱為主動(dòng)脈內(nèi)膜剝離癥或壁間動(dòng)脈瘤，是由于不同原因造成主動(dòng)脈內(nèi)膜破裂，在內(nèi)膜和中外層間有血液通過(guò)時(shí)的壓力導(dǎo)致大血管縱向剝離，形成雙腔主動(dòng)脈（double-barrel），或主動(dòng)脈瘤樣擴(kuò)張。少數(shù)病人可能沒有內(nèi)膜破裂而是中層出血形成夾層。病理變化動(dòng)脈內(nèi)膜撕裂、動(dòng)脈管壁剝離及血腫在動(dòng)脈壁中間蔓延擴(kuò)大至全層是夾層動(dòng)脈瘤發(fā)病的病理過(guò)程。動(dòng)脈內(nèi)膜的撕裂多見于升主動(dòng)脈近心端和降主動(dòng)脈起始部，即左鎖骨下動(dòng)脈開口遠(yuǎn)側(cè)。撕裂的長(zhǎng)軸常與主動(dòng)脈長(zhǎng)軸相垂直。病理變化內(nèi)膜一旦撕裂，由于血流的順向和逆向沖擊，剝離范圍會(huì)逐漸增大，對(duì)高血壓患者則更為危險(xiǎn)，管壁剝離血腫蔓延多在內(nèi)膜與中層的內(nèi)1/3和外1/3之間發(fā)展，使內(nèi)膜撕裂深達(dá)中層，并常止于中層的1/3，夾層血腫順行或逆行蔓延，可破入胸腔、心包導(dǎo)致猝死或心包填塞致死，或破入主動(dòng)脈內(nèi)出現(xiàn)第二個(gè)開口，形成主動(dòng)脈內(nèi)的假腔流道。AorticDissection流行病學(xué)特點(diǎn)多見于男性病人；多發(fā)于50－70歲；40歲以前發(fā)病患者多見于以下疾病:Marfan’ssyndrome,congenitalheartdisease,familialincidence,pregnancy,Turner’ssyndromeandtrauma等；2/3以上病人有高血壓病史。分類DeBakey:TypeI:病變包括升主動(dòng)脈、主動(dòng)脈弓和降主動(dòng)脈TypeII:限制于升主動(dòng)脈TypeIII:限制于降主動(dòng)脈TypeIIIA:橫膈膜以上；TypeIIIB:橫膈膜以下。AorticDissection分類Stanford:TypeA:包含升主動(dòng)脈TypeB:不包含升主動(dòng)脈Acute:lessthan2weeksChronic:morethan2weeksAorticDissectionNewClassification

Class1:classicalaorticdissectionwithanintimalflapbetweentrueandfalselumenClass2:medialdisruptionwithformationofintramuralhaematoma/haemorrhageClass3:discrete/subtledissectionwithouthaematoma,eccentricbulgeattearsiteNewClassification

Class4:plaqueruptureleadingtoaorticulceration,penetratingaorticatheroscleroticulcerwithsurroundinghaematoma,usuallysubadventitialClass5:iatrogenicandtraumaticdissectionClasses1through5representasubdivisiontotheStanfordorDeBakeyclassifications臨床表現(xiàn)DiagnosticFindingsPainisbyfarthemostcommonpresentingcomplaint(90%)painisdecribedas“tearing,knifelike”usuallythepainoccursquiteabruptlyandismostsevereatonsetneurologicdeficit(20%)syncope(5%)臨床表現(xiàn)PhysicalExaminationpulsedeficitsanddiscrepanciesinBPbetweenlimbsarekeydiagnosticcluespulsedeficits(50%)aorticregurgitation(50%)neurologicfindings(20%):感覺障礙,偏癱,半身麻木,向患側(cè)凝視臨床表現(xiàn)KlompasM.JAMA.2002;287:2262-72.輔助檢查RoutineLab.Tests:non-specificEKG:長(zhǎng)期高血壓損害表現(xiàn)，常合并有心肌梗死表現(xiàn)心肌酶學(xué)、肌鈣蛋白等心肌損傷標(biāo)志物檢查。影像學(xué)檢查CXRCTUltrasoundMRIAngiogram影像學(xué)檢查ChestXraymediastinalwidening(75%)“calciumsign”-uncommonbuthighlyspecific,>5mmdouble-densityappearanceoftheaortaalocalizedbulgealonganormallysmoothaorticcontour影像學(xué)檢查adisparityinthecaliberbetweenthedescendingandascendingaortaobliterationoftheaorticknobdisplacementofthetracheaornasogastrictubetotherightbythedissectionpleuraleffusions(left)影像學(xué)檢查KlompasM.JAMA.2002;287:2262-72.影像學(xué)檢查超聲心動(dòng)圖transthoracicapproach:M-mode&2-D=lowsensitivityandspecificitytransesophageal=moreaccuracyandverysensitive,canbedoneinER(safer).影像學(xué)檢查ComputedTomographydilatationoftheaortaidentificationofanintimalflapdifferentialratesofflowintrueandfalseluminathecleardemonstrationofboththetrueandfalselumina影像學(xué)檢查limitationsofCTscan:itdosenotprovideinformationaboutthepresenceofaorticregurgitationnoinformationabouttherelationshipofthedissectiontothemajorarterialbranchesoftheaortatime-consumingandrequiresthepatienttobeoutsideER影像學(xué)檢查advantagesoveraortography:（主動(dòng)脈血管造影）greatercontrastresolutionanddetectssmallordelayeddifferencesintheopacification（乳濁狀）

oftrueandfalsechannelsmaybeabletodetectathrombosedfalselumendespitenonopacificationdoesnotrequirearterialcatheterization影像學(xué)檢查Aortographyfillingofafalsechannelorchannelswithorwithoutaninterveningintimalflapdistortionofthetruelumenbyeitherapatentorthrombosedfalselumenthickeningoftheaorticwallbymorethan5-6mmcausedbyathrombosedfalselumendisplacedintimalcalcification影像學(xué)檢查disadvantagesofaortography:mostinvasive,mostexpensiverisksofintravenouscontrastmaterialinadequatedetectionofpleuralleak影像學(xué)檢查advantagesofaortography:accuratefordeterminingthesiteoftheinitmaltearandextentofthedissectioneasilydemonstratedaorticregurgitationtheonlyprocedurethatdemonstratestheextentandlocationofdissectionintoaorticsidebranches影像學(xué)檢查MagneticResonanceImagingshowsthesiteofintimaltear,typeandextentofdissection,presenceofaorticinsufficiency,anddifferentialflowvelocitiesinthetrueandfalsechannelsandintheaorticsidebranchesadvantages:nocontrastmaterial,noionizingradiation,noninvasive鑒別診斷AcutemyocardialinfarctionpainismoretypicallypressurelikebutmayradiatetothearmsorneckpaindoesnottypicallymigrateovertimeCK-MBlevelsareelevatedelevationprominentinECG鑒別診斷Pulmonaryemboluspainisgenerallyrespirophasichypoxemiasecondarytoventilation/perfusionmismatchPericarditis（心包炎）paintypicallychangeswithpositionauscultationmayrevealapericardialfrictionrubEKGiscommondiagnostic(ST-segment）CaseStudy65yoAfricanAmericanmale3daysofintermittentchestpainEpisodeslastseveralhours“Squeezing”painRadiatedtobackandleftarmPositionalCaseStudy +fevers,chills,weightloss+productivecough+hoarsevoice-hemoptysis（咳血）,orthopnea（端坐呼吸）-nausea,vomiting,diarrheaCaseStudy PMH:高血壓、NIDDM,highcholesterol;negativestressecho2monthspriortopresentationMeds:Glyburide,Glucophage,ToprolXL,Lipitor,Cozaar,ASA,Clonidinepatch>20packyearsmokinghistory,noalcohol