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Chapter10

RadiofrequencyAblationof Barrett’sEsophagus



ShajanPeterC.MelWilcox KlausMönkemüller

DEFINITION

■ Barrett’sesophagus(BE)isanacquiredconditionduetoachangeinthenormal esophagealsquamousepitheliumtocolumnarepitheliumcontaininggoblet cells.Thismetaplasticchangecanprogresstolow-gradedysplasia(LGD)and high-gradedysplasia(HGD),withthelatterhavinga5%to10%riskof developingintoesophagealadenocarcinoma.

1,2

■ Radiofrequencyablation(RFA)isasafeandeffectiveendoscopictreatment modalityforBEwherebysquamoustissuereplacestheablatedmetaplasticor dysplasticepithelium.RFAusesabipolarelectrodearraytogeneratethermal energytoresultintissuedissipation.

PATIENTHISTORYANDPHYSICALFINDINGS

■ ItmightbedifficulttodistinguishsymptomsofBEfromgastroesophagealreflux disease(GERD)clinically,althoughincreasedduration,severity,andearly ageofonsetforrefluxsymptomsaswellasobesitypredisposetoBE occurrence.

■ Ageolderthan55years,malegender,whiteethnicity,orsmokersare

predisposingfactorsforBEdevelopmentandprogressiontodysplasia. Geneticinfluencesmayplayarole,althoughonlyasmallproportion(7%)of patientswithBEhaveadocumentedfamilyhistoryofBEoresophageal cancer.

■ SelectionofpatientsforendoscopictreatmentofBErequiresamultidisciplinary approachconsistingoftheendoscopist,pathologist,andthesurgeon.

■ Confirmationofdysplasia(highorlowgrade)onbiopsiesorendoscopic mucosalresection(EMR)specimensisdonebyadedicatedgastrointestinal (GI)pathologist.

IMAGINGANDOTHERDIAGNOSTICSTUDIES

■ Detailedendoscopicexaminationwithhigh-definitionwhitelightoftheBE segmentisessentialformanagement.

■ TheextentoftheBEsegmentshouldbedefinedusingthePragueC&M classificationincludingthelengthofthecircumferentialsegment(C)andthe maximalextentoftheBEsegment(M)7(FIG1).

■ OtherimagingmodalitiesthatmighthelpindelineatingBEarenarrowband

imaging(NBI),chromoendoscopy,autofluorescenceimaging,andconfocal laserendoscopy.Theseadjunctsaidindirectedbiopsies.

■ AnyvisiblelesionsintheBarrett’ssegmentshouldbedescribedusingtheParis classification.

■ Targetedbiopsiesareobtainedfromvisibleabnormalities,followedbyfourquadrantbiopsiesofevery1to2cmoftheBEsegment(Seattleprotocol)and theseshouldbereviewedbyadedicatedGIpathologist.9Nodularlesionsare beststagedbyanEMRasdescribedinChapter11.

ENDOSCOPICMANAGEMENT

PreoperativePlanning

■ Patientsaregivenstandardesophagogastroduodenoscopy(EGD)preprocedure preparationinstructionswithspecificattentiontofactorsthatincreaseriskof sedationincludingmorbidlyobesepatients;anatomicvariantssuchasshort neck,cervicalosteophytes,cricopharyngealhypertrophy;andpriorhistoryof surgeryinvolvingtheGItract,radiation,ordocumentationofprevious strictures.

■ Noantibioticsarerequiredanditisdesirabletominimizeorstop antiplatelet/anticoagulationpriortotheprocedure.

■ EquipmentlistsforcircumferentialandfocalablationcanbefoundinTables1 and2.

Positioning

■ Thepatientisplacedintheleftlateraldecubituspositionandpreparedasfora routineupperendoscopy.

TECHNIQUES

CIRCUMFERENTIALABLATION

EndoscopywithInspectionandRecordingtheLandmarks

■ MeasurementsaretakentomaptheextentoftheBEshowing(1)topof intestinalmetaplasia(TIM),(2)proximalcontiguousareaofBE(M),(3) proximallevelatwhichtheBEiscircumferential,(4)andthetopofthe gastricfolds(TGF)(FIG2).

■ Carefulinspectionshouldbemadetoruleoutpriorulceration,strictures, previousscarringfromEMRorresidualnodularityasthesemaycompromise anyballooncircumferentialablation.Dilatationsshouldbeperformedpriorto ablation.

■ MucosaiswashedwithN-acetylcysteinetoclearanyexcessmucusandprepare thetissueforfurtherablation.

■ Afteradequateinspectionandrecordinglandmarks,aguidewireispassedinto thegastricantrumandthentheendoscoperemoved.

Sizing

■ Thesizingballoonisattachedtothecontrolunitandthencalibratedexternally alsotoruleoutanyleaks.Itisthenintroducedovertheguidewireintothe bodyoftheesophagus,placingit3cmproximaltotheTIMmeasurement.

■ Serialmeasurementsaretakenat1-cmintervals,startingproximallyand proceedingdistallybyinflatingthedeviceonthepedalprovided.The displayedmeasurementsontheconsolearethenrecordedbyatechnicianor nurse.Thesmallestdiametertreatmentballoonsuggestedthroughoutthe sizingischosenasappropriateablationcatheter.

SelectingAppropriateAblationDevice

■ Aftersizing,thecatheteristhenremoved,keepingtheguidewireinplace.

■ Thesmallestdiametertreatmentballoonsuggestedthroughoutthesizingis chosenasappropriateablationcatheterandattachedtothegenerator.

FirstAblationPass

■ TheBarrx™360RFABalloonCatheter(Covidien,Mansfield,MA)(FIG3), consistingofa3-cmelectrodearrayencirclinga4-cmlongballoon,isthen passedovertheguidewireintotheesophagus(FIG4A).Theendoscopeis intubatedalongsidethecathetertovisualizetheproximalendoftheballoon, whichisthenpositioned1cmproximaltotheTIM.

■ Theballoonisautomaticallyinflatedfirstandthenenergydeliveredbyusingthe footpedalsattachedtothecontrolunit.Theuniformenergyhasadensityof 12J/cm2andpowerof40W/cm2ablatingtoadepthof700to1,000μmover 3cmofarray(FIG4B).

■ Afterasecondofablation,theballoonautomaticallydeflatesandthe circumferentialburnisvisible.

■ Dependingonthelengthofthesegment,anadditional3cmofcircumferential ablationisperformedsuchthatthereisminimaloverlapwiththepreviously ablatedsegment(FIG4C).

CleaningProcedure

■ Theballooncatheteristhenremovedalongwiththeendoscope,leavingthe guidewireinplace.Outsidethepatient,itisinflatedandcleanedusingdamp

gauze,removingadherentablatedtissue.

■ ThetreatedareaisthencleanedofthecoagulumusingaHALOcapattachedto thetipoftheendoscope(FIG5).Afterreintroductionoftheendoscope,the coagulumisgentlyremovedusingtheedgeofthecap,debridingproximalto distalinacircumferentialmannerandthereaftercleaningwithsalinelavage. Theendoscopeisremovedandthenthecapdiscarded.

SecondAblationPass

■ Thecleanedablationcatheterdeviceisthenintroducedovertheguidewirewith theendoscopeandasecondsetofablationisperformedasdescribed previously,retreatingtheareaandfurthercoagulatinganysuperficialblood vesselspreventingbleeding.

FocalAblation

■ Thefocalablationisperformedfortreatingshortersegments,tonguesand islandsofBE,andduringfollow-upafteraninitialcircumferentialRFA.It mayalsobeofspecialuseintreatingareasadjacenttothesquamouscolumnarjunction.

■ Aftercarefulendoscopicexamination,theareasarerecordedandendoscope

removedwhileexternally,theHALO90device(arraymeasuring13×20mm) isattachedtothetipofthescope.Itispositionedsuchthatthebackofthe thumb-shapedarrayislocatedat12o’clockpositionontheendoscopicfield ofviewandcanbepivotedeasily.Itisreintroducedintoesophagusafter carefulintubation.

■ TheesophagusiswashedwithN-acetylcysteinesolution.Thetargetedareaof BEisidentifiedandtheendoscopeisangulatedsuchthattheablationdevice istightlyopposedtothemucosa(FIG6A).

■ Aftermaintainingoptimalcontact,theenergyisdeliveredusingthefootpedal usingthesimilarenergysettingspreviouslydescribed.Maintainingthesame position,asecondpulseofenergyisgiven.Thedeviceisthenmovedtothe nexttreatmentareaandpreviouslymentionedstepsrepeated,treatingall visualizedBE(FIG6B).

■ ThecoagulumofdesiccatedmucosaisthenremovedusingeitheraHALOcap aspreviouslydescribedoreventhetipoftheablationdevicecouldbeusedto scrapethetissue.Aftergentledebridement,thedeviceisthenexternally cleanedusingdampgauze,reintroducedwhilemountedonthescopeanda secondroundoftwoapplicationsperareaareperformedinanidentical mannersuchthateventuallyeachtargetedareareceivesatotaloffourenergy ablations.

FOLLOW-UP

■ Endoscopicevaluationoftheablatedareaisperformed2monthsfollowingthe procedure,andcompletehealingshouldhaveoccurredbythistime(FIG7).

PEARLSANDPITFALLS

Indications ■Carefulhistory,endoscopicfindings,andpathologic

reviewofrecordsshouldbedonepriortoselection ofpatientsforablation.

Selectionofablation method

■Long-segmentcircumferentialareasshouldbe

targetedusingthecircumferentialHALO

360

device.

■Shortsegmentandsubsequentsessionsor“touch

up”ofBEcanbetreatedusingthefocalHALO

device.

Circumferential ablation

■Endoscopicidentificationoflandmarksandlength

onsegmentbasedonPragueclassification

■Sizingofdeviceandselectionofballoonablating

catheter

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