Esophageal variceWord格式文档下载.docx
- 文档编号:20589166
- 上传时间:2023-01-24
- 格式:DOCX
- 页数:15
- 大小:462.16KB
Esophageal variceWord格式文档下载.docx
《Esophageal variceWord格式文档下载.docx》由会员分享,可在线阅读,更多相关《Esophageal variceWord格式文档下载.docx(15页珍藏版)》请在冰豆网上搜索。
Mechanicsandhemodynamicsofesophagealvaricesduringperistalticcontraction
LarryS.Miller,1JosephK.Kim,1QingDai,1JyothiMekapati,1JamesIzanec,1ChanChung,1Ji-BinLiu,4AndrewSanderson,1MattBohning,1JoshDesipio,1JasneetGandegok,1JustinJ.Harberson,1CarsonSchneck,1MarkA.Nicosia,3VinodThangada,1BejeThomas,1BrianCopeland,1ElanMiller,1AaronMiller,1NajiAhmed,1andJamesG.Brasseur2
1TempleUniversityHospital,Philadelphia19140;
2ThePennsylvaniaStateUniversity,UniversityPark16802-1412;
4ThomasJeffersonUniversityHospital,Philadelphia,Pennsylvania19107;
and3UniversityofMinnesota,Minneapolis,Minnesota55455
Submitted13January2004;
acceptedinfinalform15June2004
Ourhypothesisstatesthatvaricealpressureandwalltensionincreasedramaticallyduringesophagealperistalticcontractions.Thisincreaseinpressureandwalltensionisanaturalconsequenceoftheanatomyandphysiologyoftheesophagusandoftheesophagealvenousplexus.Thepurposeofthisstudywastoevaluatevaricealhemodynamicsduringperistalticcontraction.Asimultaneousultrasoundprobeandmanometrycatheterwasplacedinthedistalesophagusinninepatientswithesophagealvarices.Simultaneousesophagealluminalpressureandultrasoundimagesofvariceswererecordedduringperistalticcontraction.Maximumvaricealcross-sectionalareaandesophagealluminalpressuresatwhichthevarixflattened,closed,andopenedweremeasured.Theesophageallumenpressureequalstheintravaricealpressureatvaricealflatteningduetoforcebalancelaws.Themeanflatteningpressures(40.11±
16.77mmHg)weresignificantlyhigherthanthemeanopeningpressures(11.56±
25.56mmHg)(P
0.0001).Flatteningpressures>
80mmHgweregeneratedduringperistalticcontractionsin15.5%oftheswallows.Varicealcross-sectionalareaincreasedameanof41%abovebaseline(range7–89%,P<
0.0001)duringswallowing.Thepeakclosingpressuresinpatientsthatexperiencefuturevaricealbleedingweresignificantlyhigherthanthepeakclosingpressuresinpatientsthatdidnotexperiencevaricealbleeding(P<
0.04).Patientswithameanpeakclosingpressure>
61mmHgweremorelikelytobleed.Inthisstudy,accuracyofpredictingfuturevaricealbleeding,basedonthesecriteria,was100%.Varicealmodelsweredeveloped,anditwasdemonstratedthatduringperistalticcontractiontherewasasignificantincreaseinintravaricealpressureoverbaselineintravaricealpressureandthatthepeakintravaricealpressuresweredirectlyproportionaltotheresistanceatthegastroesophagealjunction.Inconclusion,esophagealperistalsisincombinationwithhighresistancetobloodflowthroughthegastroesophagealjunctionleadstodistensionoftheesophagealvaricesandanincreaseinintravaricealpressureandwalltension.
esophagealvarices;
simultaneousultrasoundandmanometry;
varicealbleeding
ESOPHAGEALVARICEALBLEEDINGoccurswhenanexpandingforcewithinthevarixexceedsthemaximumwalltension.Walltensionisaninwardlydirectedforceopposinganoutwardlydirectedexpandingforce.WalltensioncanbecalculatedbytheLaplaceequation.TheLaplaceequation(WT=pv–pexr/w)statesthatthewalltension(WT)isequaltothetransmuralpressuredifference(pv–pe)(wherepvistheintravaricealpressureandpeistheesophageallumenpressure)timestheradiusofthevarix(r)dividedbythewallthickness(w).Thusthisforceisdirectlyproportionaltothetransmuralpressuredifferenceandtheradiusofthevarixandinverselyproportionaltothewallthicknessofthevarix.
Nomethodsarepresentlyavailablethatcanmeasurevaricealpressuresduringaperistalticcontractionoftheesophagus(1–3,7,12).Ourhypothesis,basedonthedatageneratedinthisstudy,statesthatvaricealpressureandwalltensionincreasedramaticallyduringesophagealperistalsisasanaturalconsequenceoftheanatomyandphysiologyoftheesophagusandoftheesophagealvenousplexus.
Theobjectiveofthisstudywastoestimatevaricealpressureandwalltensionandtocharacterizethemechanicalandhemodynamicbehaviorofesophagealvaricesduringperistalticcontractions.Thiswasdonethroughmeasurementsonpatientswithesophagealvaricesandinamodelvarixsystemthatsimulatesintravaricealpressuregeneratedduringperistalsis.
MATERIALSANDMETHODS
PatientStudies
ThisstudywasapprovedbytheinternalreviewboardatTempleUniversityHospital.Ninepatients(8menand1womanwithameanageof53.1±
10.9yr)withcirrhosis,portalhypertension,andesophagealvaricesdocumentedonprioroutsideendoscopywereevaluatedinthisstudy.TheetiologyofthecirrhosiswashepatitisCintwopatients,hepatitisBintwopatients,alcoholintwopatients,hepatitisBandCinonepatient,alcoholandhepatitisCinonepatient,andcryptogenicinonepatient.Noneofthepatientswastreatedwithbetablockersduringthestudyasperthereferringphysicians.Noneofthepatientshadbledfromesophagealvaricesbeforethestudy.
Esophagealvariceswereimagedincrosssectionwithhigh-frequencyendoluminalsonography,usinga20-MHzultrasonographytransducer(Olympus,Tokyo,JapanorMicrovasive,BostonScientific,Boston,MA).Thetransducerproducesareal-time360°
cross-sectionalultrasoundimageoftheesophagus.Real-timeimageswererecordedonSuperVHSvideotapeusingaKayelemetricsswallowingworkstation(Kayelemetrics,LincolnPark,NJ).
A3Fangiographycatheterwasgluedtotheultrasoundcathetertomeasurepressureintheesophageallumen.A1-mmsideportwasmadeintheangiographycatheteratthesamelevelastheultrasoundtransducer.Thedistalendofthecatheterwasclosedwithsiliconglue,whereastheproximalendwasattachedtoawater-perfusedmanometrysystem(Arndorfer,Milwaukee,WI).Waterwasperfusedatarateof0.5ml/minatapressureof15lb./in.2.ThemanometrysystemwasattachedtoaKayelemetricsswallowingworkstation,whichwasthenusedtosynchronizethepressuretracingswiththecorrespondingultrasoundimages(Fig.1).
Viewlargerversion
Fig.1.Simultaneousultrasoundimagesandmanometrypressurecurves.A:
displayscreenontheKayelemetricsworkstationwiththeesophagusatrest.Thedisplayscreenshowstheultrasoundimage.Notethelargeopenvarixismarked.Theesophageallumenpressureis12.4mmHg.B:
displayscreenshowingsimultaneousultrasoundandmanometryduringtheperistalticcontraction.Notetheflattenedvarixismarked.Theesophageallumenpressureatexactlythepointofvaricealflatteningis94.4mmHg.Intravaricealpressureandtheesophageallumenpressureareequalatvaricealflattening.
Allstudieswereperformedafteranovernightfastwithsubjectsinasupinepositionandwiththepatient’sheadelevatedat30°
.Viscouslidocaine(1%)wasadministeredfornasalanesthesia.Thedual20MHzultrasound/manometrycatheterwaspassedtransnasallythroughtheesophagusandintotheproximalstomach.Thedualcatheterwasthenpulledintotheesophagealbodyatalevelabovethegastroesophagealjunctionwherethevaricesappearedthelargest.Thetransducerwasstabilizedinpositionatthislevel,andrestingesophageallumenpressure(withbreathing)wasmeasuredforatleast10sandthenusedasthezerobaseline.Subjectswereaskedtorepeatedlyswallowabolusof5mlofwater,withatleast1minbetweenswallows,whiletheinvestigatorscontinuouslyacquiredultrasoundimagesandsimultaneouspressuredata.
StillimagesweredigitizedandanalyzedbyusingImageProPlussoftware(MediaCybernetics,SilverSpring,MD).Incompleteorinadequatetracingsorimagesduetoartifactwerenotusedforevaluation.Themaximumcross-sectionalareaofthevarixatrestandatmaximumdistensionwascalculatedbytheImageProPlussoftware,fromtheoutlinedstillimagesofthevarix.Theimageofeachvarixwasoutlinedattheborderofthehyperechoicinnervaricealwallandthehypoechoicbloodwithinthevarix.Thereadersoftheimageswereblindedtothepressuredata.Pressuremeasurementswerereaddirectlyfromthedatastoredandpresentedontheswallowingworkstation.
Ultrasoundimagingofthevarices,duringswallowingofwater,showedthatthevaricesinitiallyincreasedinsize,thendecreasedinsize,andthenflattened,closed,andopenedsequentially.Varicealclosurewasdefinedasthefirstpoint,ontheultrasoundimageduringtheperistalticcontractionatwhichthehypoechoicbloodwithinthevarixwasnolongervisibleintheimage.Peakclosingpressurewasdefinedasthepeakesophageallumenpressureatwhichaparticularvarixclosed.Varicealflatteningwasdefinedasthepointatwhichtheexposed(esophageallumen)sideofthevarixflattenedduringtheperistalticcontraction(Fig.2).Becausethevideotapeofthevaricescanberuninaforwardorbackwarddirection,varicealflatteningwasusuallydeterminedbyfindingthepointofvaricealclosureandthenbackingthevideotapeuptothepointofvaricealflattening.Varicealopeningwasdefinedasthefirstpointatwhichthehypoechoicbloodinthevariceallumenwasagainvisibleaftervaricealclosing.Thepointsatwhichthevarixclosed,flattened,andopenedwereidentifiedwiththecorrespondingpressuresontheesophageallumenpressurecurves.Varicealflattening,closing,andopeningpressureswerereferencedtobaselineesophagealpressureintherestingstate.Variceswerelabeledontheultrasoundimagetoidentifythesamevarixduringmultipleswallows.Theamplitudeofthepeakesophageallumenpressureduringtheperistalticcontractionwasrecordedand
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Esophageal varice