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Ростовский Государственный Медицинский Университет

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Книга_3751_Библиотеки_им_академика_М_И_Перельмана

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aortic wall injury is higher than with stent angioplasty or surgery. This is likely related to the overdistensionneededtoachieveatherapeuticresult.

3.Somestudieshaveshowntheriskofpostangioplastyaorticaneurysmformationtobeashighas35%.

27,28

Ratesofrecoarctationfollowingballoonangioplastyhavebeenreportedtorangeanywherefrom8%

to32%.

27,29,30

Inaprospective,multi-institutional,observationalstudy,balloonangioplastywasfoundto

be inferior to stent angioplasty for the treatment of native aortic coarctation. In this study, gradient reduction with balloon angioplasty alone was less than that seen with stent angioplasty or surgery. Furthermore,therateofaorticwallinjuryandaneurysmformationwassignificantlyhigherwithballoon angioplasty compared with stent angioplasty. Compared with its use in native coarctation, balloon angioplastyresultsinbettergradientreductionandlessaorticwallinjurywhenusedforthetreatmentof recurrentcoarctation.

4.Inourpractice,balloonangioplastyisgenerallyreservedforthetreatmentofrecurrentcoarctationin

infants and young children whose vasculature is too small to allow placement of a stent capable of reachinganticipatedadultaorticdimensions.SeeTable5A.2forequipment.

Table5A.2

BalloonAngioplastyEquipment:DescriptionandUses

Cathete rs

■Soft-tipped,atraumaticend-holecatheters

■Helpfulforcrossingthecoarctationanddeliveringguidewires

■Multimarkerpigtailangiographiccatheters

■Helpfulforcalibrationandlengthassessment

■Multi-Trackangiographiccatheter(NuMED,Inc.,Hopkinton,NY)

■Allowsforhemodynamicandangiographicassessmentwithoutneedtoremovetheguidewire

Balloons

■Noncompliantangioplastyballoonswithshortshouldersarepreferred

■Preciseinflationpressure/balloondiameterrelationshipsareneededforsafeangioplasty

Guidewires

■ExchangelengthguidewireswithenhancedstiffnesssuchasRosenWiresorAmplatzExtra-Stiffwires

Sheaths

■Sheathsmustbeabletoaccommodatetheangioplastyballoonsbeingusedandprovidegoodhemostasisataortic

pressurewhenawireandcatheter(suchastheMulti-Trackcatheter)areacrossthehemostaticvalve

■Largediameter(12-14French),long(75-90cm)sheathsshouldbeavailable,shouldemergentcoveredstent

placementbenecessary

Largediamete r covered stents

■Intheeventofaseriousaorticwallinjurysuchasalargedissection,acuteaneurysmformation,oraorticwall

rupture,coveredstents—balloonexpandableorself-expanding—ofsufficientdiameterforuseintheaortashouldbe immediatelyavailable,andtheoperatorshouldbecomfortablewiththeiruse.Giventhespectrumofaortic coarctation,thisnecessitatesaninventoryofvarioussizesandlengths

■Inourpractice,werelyontheMountedCPCoveredStent(NuMED,Inc.,Hopkinton,NY).Thesecanbedelivered

througha12or14Frenchsheathandmostcanbeexpandedto30mm.Thesestentsexhibitsignificant foreshortening,andthuscarefulreviewofthestentlengthattheintendedimplantdiameterisnecessary

B.TechniqueandProceduralConsiderationsforBalloonAngioplasty

1.KeyPoints

Excellent and detailed discussion of the techniques and materials required for coarctation balloon angioplastycanbefoundinDrCharlesMullins’textbookCardiacCatheterizationinCongenitalHeart

https://t.me/med1917

Disease.31Thefollowingkeypointsshouldbeconsidered:

a. Werecommendthatallpatientsundergopreproceduralimaging—eitherCTAorMRA.

b. Werecommendtheuseofgeneralanesthesia,asaorticwallinterventionsarepainfulandinadvertent

patientmovementcanresultinsignificantcomplications.

c. Typeandcross-matchedbloodshouldbeavailableintheroomduringtheprocedure.

d. A careful hemodynamic assessmentshould beperformed prior to intervention. In cases wherethe

indicationforinterventionwill dependontheinvasivehemodynamicassessment,onemaywantto perform a baseline assessment prior to induction of general anesthesia. If the presence of a significantobstructionisconfirmed,thepatientcanthenbeinducedpriortointervention.

e. Detailed,multiplaneangiographyshouldbeperformedpriortoanyintervention.

i. Inourpractice,weroutinelyuserotationalangiographytoassesstheaorticarchandcoarctation

anddeterminetheoptimalgantryangleforintervention.

ii. Utilizeanangiographiccatheterwithcalibrationmarkerstoallowforaccuratemeasurements;

thewidthofacatheterdoesnotprovideasufficientlyaccuratereference.

2.BalloonDilation

a. Usuallyperformedwithasingledilationballooninaretrogradefashion.

b. Selectaballoonthatis2.5-3timeslargerthanthenarrowestcoarctationdiameterbutnotlargerthan

diameterofthesmallestadjacent“normal”aorticlumen.Balloons>3timesthenarrowestdiameter increasetheriskforvesseldisruption,whereasthoselargerthantheadjacentnormalvesselincrease theriskofinjurytothenormalaorticwall.

c. Thelengthoftheballoonshouldbelongenoughtocovertheareaofcoarctationcompletely,without

extendingtoofarineitherdirection,thusavoidinginjurytothenormalaorticwall.

d. Thedistalendofthewireisusuallyfixedintherightorleftsubclavianartery.Iftheselocationsare

inadequate,thewirecanbefixedintheaorticroot;however,thispositionofferslessstability.Under nocircumstancesshouldthewirebepositionedinacarotidorvertebralartery.Theballoonshould bemeticulouslyprepped prior toinsertion sothatitis free ofair—ie, “negativeprep”. Thiswill avoidinadvertentairembolizationintheeventofaballoonrupture.

e. Theballoonshouldbecenteredacrossthestenosis,andcareshouldbetakentobesuretheproximal

shoulderdoesnotextendintoasmallcalibervessel—ie,thesubclavianartery.

f. Apressuremanometer should be used,andinflationpressuresshouldnotexceedtheballoonburst

pressureor4-6atm—whicheverisless.

g. Ballooninflationshould be stoppedifanadequatewaistdoes notappearor theballoonbecomes

displaced.

h. Leaving the guidewire in place, postdilation angiography should be repeated to assess for

improvementinthecoarctationandtoevaluate foraortic wallcomplicationsincludingdissection, aneurysmformation,andrupture.

i. Toavoid vessel dissectionor perforation,thedilatedsegmentshould onlybe recrossed over the

previouslyplacedguidewire.

3.ProgradeCatheter

Theuseofaprogradecatheterisreservedforspecialcases.

a. A prograde catheter froma radialorbrachial arterialaccesssitecanbe used toassistinballoon

positioning;tomonitorpressuresbefore,during,andafterthedilation;andforangiography.

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i. Advantages: Allows for these measurements and angiography prior to obtaining arterial

access. Postprocedure, allows for angiography without requiring any manipulation of wires/cathetersacrossafreshlydilatedcoarctation.

b. Aprogradecathetercanalsobeusedfromavenousaccesssiteviaatransseptalapproach.

C.ComplicationsFromBalloonAngioplasty

1.Complicationsrelatedtotranscatheterballoonangioplastyofaorticcoarctationcanbeclassifiedinto

3categories:(1)technical,(2)aortic,and(3)peripheralvascular.

a. Technicalcomplicationsincludeissueswiththeequipmentorproceduraltechniqueandinclude

balloonrupture,balloondisplacement,andguidewireinjury.

b. Aorticwallinjuryiscommonandincludesintimaltears,aorticdissection,andaneurysmformation.

i. IntheCCISCstudy,therewasa10%incidenceofacuteaorticwallinjuryandanincidenceof

21.4%inshort-termfollow-up(3-18mopostprocedure).

ii. Acutely,allcasesofaorticwallinjurywererelatedtodissection,whereasintheshort-term

follow-upgroup,themajorityofcaseswereduetoaneurysmformation.

iii. Inintermediatefollow-up(18-60mopostprocedure),theincidenceofaorticwallinjury

increasesto43.8%,mostofwhichareduetoaneurysmformation.

iv. Thisspeakstotheimportanceofpre-andpostinterventionangiographyandintervalfollow-up.

Asdiscussedpreviously,itiscriticaltomaintainaninventoryofappropriatelysizedcovered stentsforuseinemergencysituationssuchasacuteaneurysmformationorrupture.

c. Peripheralvascularcomplicationsaresimilartothoseseeninanycardiaccatheterizationwith

arterialaccessandincludecerebralvascularaccidents,peripheralemboli,andinjurytoaccess vessels.

2.Accesssitecomplicationsareofparticularconcern,astheseproceduresoftenrequiretheuseoflarge-

sizearterialsheaths.

a. Adequacyoffemoralandiliacvesselsizeshouldbeassessedpriortotheintroductionoflarge-

diametersheaths.

b. Inourexperience,arteriotomyclosuretechniquessuchas“preclosure”oftheaccesssitewiththe

PerCloseProGlide(AbbottVascular,SantaClara,CA)canhelpreducepostproceduralbleedingand hematomaformationinappropriate-sizepatients.

D.StentAngioplasty

1.StudiesandEvaulations:

Balloon-expandablestentangioplastyforbothnativeandrecurrentaorticcoarctationhasbeenextensively evaluated over the past decade. In some studies, stent angioplasty has been shown to be superior to balloonangioplastyandsurgeryforthetreatmentofnativeaorticcoarctation.

25,29

a. Additionally, theratesofaneurysm formation and otheraortic wall complicationsfollowing stent

angioplastyofrecurrentcoarctationarelessthanthoseassociatedwithballoonangioplastyalone.

b. A prospective, multi-institutional registry study of 302 patients (median age 15 y, range 2-63 y)

undergoingstentangioplastyforcoarctation(55%native)foundnoproceduralmortality.Procedural adverseeventswereseenin5%includingacuteandintermediateaorticwallcomplicationsin1%

https://t.me/med1917

and2%,respectively.

2.Preferences:

Inourpractice,wefavorstentangioplastyforbothnativeandrecurrentaorticcoarctationinadolescent andadultpatients.Avarietyofstents are available withachievable diameters sufficientforuseinthe treatment ofaortic coarctation. However,only the CheathamPlatinum(CP) Stent and the Covered CP Stent (NuMED, Hopkinton, NY) carry a specific indication for use in native and recurrent aortic coarctation.Inour practice, we use a varietyofballoon-expandable stents.Theuseofself-expanding nitinol stents and stentgrafts forthe treatmentofnative andrecurrentcoarctation has been described; however,availabledataregardingtheiruseandoutcomesarelimitedtosmallcase series.33Thus,this chapterwillfocusonballoon-expandablestents.

3.StentSelection:

Stent selection depends uponseveral factors: the diameter required to avoid residual obstruction; the necessaryradialstrengthtomaintainstentandlumenintegrity;theanatomyofthelandingzone(straightor curvilinear);theneedtocrossorjailbrachiocephalicvessels;andtheneedforacoveredstent.Itshould be notedthat onlythe CP stentandCovered CP stentareavailable premounted on a delivery balloon catheter.Currently,allotherstentsmustbehand-crimpedontoanappropriatelysizedballoon.

a. ThePalmazXL10seriesofstents(J&J)areclosed-cellstentslaser-cutfromaveryrigidstainless-

steel tubeandare capable of expandingto28 mmin diameter.They are available in30, 40, and 50 mm, lengths, but at aortic diameters (16-28 mm), there is marked foreshortening. Thus, it is important tohavea foreshortening chart available so thatanappropriate stent lengthis selected. These stents have high radial strength butare inflexible andunmalleable, thus they are ideal for discrete coarctations in straight segments of the aorta. They will not conform to curvilinear anatomies and may cause severe distortion or vessel injury when used in such an environment. Finally,theclosed-celldesignlimitstheabilitytoopencellsbeyondafewmillimetersinsituations whereabrachiocephalicvesselisintentionallyorunintentionallyjailed.ThePalmazGenesisfamily ofstentsareavailablein3sizeranges—medium,large,andXD—“extra-diameter.”

LargediametercoveredstentssuchastheCoveredCPstentshouldbeimmediatelyavailable incaseofaorticwallinjury. Stentselectionismultifactorial:theanatomyofthelandingzone,diameterrequiredtorelieve theobstruction,radialstrengthofthestent,theneedtojailheadandneckvesselsandtheneed foracoveredstentareallimportantconsiderations.

Thesestentscanonlyreach18mmindiameter,limitingtheirusetopatientswithoverallsmalleraortic dimensions.TheGenesisXDisavailable inlengths from19to59 mm.Likethe PalmazXLstents,the GenesisXDstentsarelaser-cutfromstainlesssteel,havegoodradialstrength(althoughlessthanthatof the XL stents), and have a closed-cell design. This stent introduced an “S”-shaped “sigma hinge,” allowingthestenttoflexaroundcurves,andreducedthedegreeofshorteninguponfullstentexpansion. Thus,inpatients with a relatively smallaorta,the Genesis XDis agoodchoiceforuseincurvilinear anatomies.Theclosed-celldesignofthePalmazGenesisseriesmaylimittheabilitytoopenthecellsin situations where brachiocephalic vessels are crossed. However, with currently available ultra-highpressureballoons,thestentstrutscanusuallybefracturedwhennecessary,althoughthismaynegatively

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affectstentintegrity.Asmentioned,thesestentshavelessradialstrengththanthePalmazXLstentsand,in ourexperience,areatincreasedriskforfractureovertime.

a. Theev3IntraStentLDMaxwasapprovedforusein2002.Thesestentshaveuniquecharacteristics

includinganopen-celldesignthatreducesstentforeshorteningandallowsforexpansionofcellsup to 12 mm. With staged or sequential expansion,these stents can be expanded to 24-26 mm with minimal foreshortening.However,when expanded tofulldiameter with a singleballooninflation, theywillforeshorten.Thus,theyshouldonlybedeployedusingaballoon-in-balloon(BIB)catheter (NuMED,Hopkinton,NY)asdiscussedlater.Theyareavailableinlengthsof16,26,and36mm. Theopen-celldesignaffordsagreatdealofflexibilitymakingthisstentquiteamenabletoplacement incurvilinearanatomies. TheirradialstrengthislessthanthatoftheGenesisXDstents.Also,the open-cell design results in less metallic coverage and thus less support of the aortic wall. We reserveuseofthisstenttonarrowingwithinthecurvatureoftheaorticarchandinsituationswhere weanticipatejailingabrachiocephalicvessel.

b. TheNuMEDCPstentistheonlystentspecificallyapprovedforuseinaorticcoarctation.TheCP

stentwasdesigned tohaveroundededgestoreduceaortic wallinjury. Thezig-zag patternofthe stentcreatesaclosed-cellconfigurationwithsomeaddedflexibility.In2007,theCoarctationofthe AortaStentTrial(COAST)wasinitiatedtoassessthesafetyandefficacyoftheCPstentwhenused inadultsandchildrenwith native or recurrentcoarctation.34In long-termfollow-up,these stents havegenerallybeenbelievedtobesafeandeffective.Stentfracturehasbeencommoninfollow-up, butclinicallyinsignificant.Thereinterventionratewas13%andgenerallyduetoaorticwallinjury or forplannedstentdilation.34Thisstenthaslarge cells and is quitemalleable making itagood choiceforcurvilinearanatomies.Itisavailablebothpremounted(onaBIBcatheter)andunmounted. Itisavailableinlengthsfrom16to45mmandindiametersfrom12to30mm.AswiththePalmaz XLstents,theCPstentsforeshortensignificantlywithexpansion,andthusitiscrucialtorefertoa foreshorteningcharttoaccuratelypredictthefinalstentlengthattheintendedimplantdiameter.

c. TheCovered Cheatham Platinumstent(CCPS) is a bare-metal CP stent covered along almost its

entirelengthwithanexpandable sleeve ofePTFE(expandedpolytethrafluoroethylene;Fig. 5A.1). Thefabricsurroundingthestentisthoughttoprovideseveraladvantagesoverbare-metalstents:(1) additionalstructuralsupport,(2)aprotectivebarrieratthesiteofstentplacement,(3)areductionin shearstress.27One limitation of thisstent is theneedforlargersheathsizes. Moreover,the stent mustbecarefullypositionedtoavoidunintendedobstructionofbrachiocephalicvessels.TheePTFE doesnotextendallthewaytotheedgeofthestent;thismustbeconsideredwhenattemptingtocover a specific anatomic location. The COAST II trial demonstrated the ability of the CCPS to treat and/orpreventaorticwallinjuriesrelatedtocoarctation.23Long-termfollow-upisongoing.These stents (or a large diameter, covered, self-expanding stent or endograft) can provide life-saving coverageofpotentiallycatastrophicaorticwall injuriesandthusshouldbeimmediatelyavailable when performing balloon or bare-metal stent angioplasty. In patients with resistant lesions, ie, coarctationsthatwillnotresolveat<5-6atmwitheitherballoonorbare-metalstentangioplasty,we recommendimplantingaCCPSthatextendswellpastthelesionpriortohigher-pressureexpansion. Inolderpatients,especiallythosewithvisiblecalciumwithintheaorticwall,weimplantaCCPS primarilybecauseoftheknownrisksofaorticwallinjuryinthispopulation.

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4.Equipment:

Much of the equipment needed for balloon angioplasty should also be available for stent angioplasty procedures, including, soft-tipped end-hole catheters, stiff guidewires, Multi-Track angiographic catheters,calibratedpigtailcatheters,large-diameterlongsheaths,andlarge-diametercoveredstents.

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5.SpecificBalloons:

WealmostexclusivelyusetheBIBcatheter(NuMED,Hopkinton,NY)forstentimplantationinadolescent andadultpatients.

a. This BIB catheter is specifically designed for stent placement and consists of two “nested”,

independently inflatable balloons on a single catheter shaft. It is available with outer balloon diametersof8-30mm.Theinnerballoonis½thediameterand10mmshorterthantheouterballoon.

b. When manually mounting a stent, the stent is centered and crimped on the outer balloon. The

premountedCPstentandCCPScomemountedontheseballoons.Onceatthetargetlesion,theinner balloonisinflated,expandingthe centerportionofthestentpriortothe proximal anddistalends. This prevents “dog-boning,” where the shoulders of the balloon and hence the ends of the stent expandfirst,andreducestheriskofthestent“milking”duringexpansion.Furthermore,withthestent fixedat½itsintendeddiameter,angiographyandrepositioncanbeperformedpriortoinflationof the outer balloon.Theabilitytoperform staged expansionallows the ev3 Mega LD stents tobe implantedwithminimalforeshortening.

c. Postimplant dilation is occasionally required after placement of a covered stent in a resistant

stenosis. Our inventory includes Z-Med II balloons (NuMED Inc., Hopkinton, NY) and VIDA balloons (BARD, Tempe AZ) forthis purpose.TheVIDA balloonsarelow profile andare often usedforlatepostdilationmonthsafterinitialimplant,thuslimitingtheneedforlargesheaths.

6.Wires

a. Mostoperatorsusealong,stiffwirewithasofttipsuchasaRosenwireortheAmplatzSuper-Stiff

wire

b. AllBIBcatheterstrackover0.035inchwires

7.Sheaths

a. Allhand-mountedcathetersrequiredeliverythroughalongsheath.Mostpopular:straightCookRB-

Mullinssheaths.

b. To accommodate the added stent material, a sheath2-3 French sizes larger than required forthe

angioplastyballoonshouldbechosen.

8.Large-DiameterCoveredStents

a. Intheeventofaseriousaorticwallinjurysuchasalargedissection,acuteaneurysmformation,or

aortic wallrupture,covered stents—balloon-expandableor self-expanding—ofsufficientdiameter foruseintheaortashouldbeimmediatelyavailable,andtheoperatorshouldbecomfortablewith theiruse.Giventhespectrumofaorticcoarctation,thisnecessitatesaninventoryofvarioussizesand lengths.

b. Inourpractice,werelyontheMountedCPCovered Stent(NuMED, Inc., Hopkinton,NY).These

canbedeliveredthrougha12or14Frenchsheathandmostcanbeexpandedto30mm.Thesestents exhibitsignificantforeshortening,andthuscarefulreviewofthestentlengthattheintendedimplant diameterisnecessary.

E.TechniqueandProceduralConsiderationsforStentAngioplasty

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1.KeyPoints:

Excellentanddetaileddiscussionofthetechniquesandmaterialsrequiredforcoarcationstentangioplasty canbefoundinDrCharlesMullins’textbookCardiacCatheterizationinCongenitalHeartDisease

andinCoarctationoftheaorta:Stentinginchildrenandadults,anexcellentreviewbyDrsGoldenand Hellenbrand.24Thefollowingkeypointsshouldbeconsidered:

a. Generalanesthesiashouldbeused,asstentangioplastyispainfulandpatientmovementcanresultin

amyriadofcomplications.

b. Cross-matchedbloodshouldbeimmediatelyavailable.

c. As described earlier for balloon angioplasty, careful measurement of the gradient across the

coarctationanddetailed,multiplaneangiographyshouldbecompletedpriortotheintervention.

d. Use of a calibrated angiographic catheter is essential. Detailed measurements of the coarctation,

proximalanddistalaorticdiameters,thelengthofthelesion,andthedistancetothebrachiocephalic vesselsshouldbemade.Thiswilldictateballoonandstentsizeselection.

e. Similartoballoonangioplasty,astiffwireshouldbeanchoreddeepinasubclavianartery:

i. Forlesionsinthetransversearch,wirepositioningintherightsubclavianarterycanhelpkeep

theballoonandstentstraight.

ii. For lesionsin theproximal descendingaorta,wire placement in theleftsubclavianarteryis

ideal.

f. In tortuous and or highlystenotic lesions, it may be helpful to cross the lesion from a radial or

brachial artery approachandthensnareandexternalizea guidewire from thedescendingaortato allowretrogradepassageofcatheters.

g. Someoperatorschoosetotestthecomplianceofthecoarctationlesionpriortointervention:

i. Useaballoonthatisatleast2mmsmallerindiameterthantheintendedstent.

ii. Inflate balloon to low pressure (ie, not more than 2-3 atm). If there is a significant waist

remaining on the balloon, one may choose to implant the stent at a smaller diameter and postponecompleteexpansionofthestentuntilasecondcatheterization6ormoremonthslater. Thisallowstime for thestentand surroundingtissuetomatureandmaydecreasethe riskof aorticwallcomplications.

iii. Predilationofthecoarctationwiththeintenttodisrupttheintimashouldnotbeperformedprior

tostentplacement.Thishasbeenshowntoincreasetheriskofaorticwallcomplications.

2.StentSelection(Table5A.3)

Table5A.3

AvailableStentsforStentingofCoarctationoftheAorta(CoA)

Stent-Alone Available

Lengths(mm)

Maximum Diameter(mm)

CellDesign CoarctationApplication

PalmazXL 30,40,50 28 Closed/fixed DiscreteCoAinstraightsegmentsoftheaorta MaxLD 16,26,36 26 Open/dilatable

12mm

Transversearch;lesionswithriskofimpingingonhead vessels;curvilinearsegments

MegaLD 16,26,36 18 Open/dilatable

12mm

Transversearch;lesionswithriskofimpingingonhead vessels;curvilinearsegments

GenesisXD 19,25,29,39,

18 Closed/dilatable Smalleraortas;curvilinearsegments

CheathamPlatinuma16,22,28,34,

39,45

24 Closed/dilatable Curvilinearsegments

CoveredCheatham Platinum

16,22,28,34, 39,45

24 Closed/covered Lesionswithhighriskofaorticwallinjury

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Availableunmountedorpremountedonaballoon-in-balloondeliverycatheter.

a. Onemustbecognizantofthemaximumdiameterofthestentbeingselected.TheGenesisXDstent

can only reach 18 mm in diameter and thus should only be used in fully grown patients with relativelysmallaorticcaliber.

b. The anatomic landscape—curvilinear segment versus straight aortic segment—may necessitate a

moreflexiblestent.

c. Theneedtocrossorjailbrachiocephalicbranchesmaywarrantuseofanopen-cellstentsothatthe

coveringcellcanbedilated.

d. Some operators choose to implanta covered stent in most if notall patients. Certainly, inolder

adultsandthosewithcalcificationatoradjacenttothecoarctation,acoveredstentshouldbeused primarily,asthereisahigherriskforaorticwalldisruptioninthesepatients.

e. Inpatientswithnoncompliantlesions—ie,thoserequiring>4-5atmofpressuretoopen—acovered

stentshould beused.Thisholdstrueforpatients undergoingastagedexpansionwithabare-metal stent.If,atthetimeofthesecondprocedure,thelesionisstillresistant,acoveredstentshouldbe placed insidethe original bare-metal stent(extendingbeyond both ends ofthe bare-metal stentto avoidendoleak)priortousinghigherpressuretoexpandthelesion.

3.BalloonSelection

a. Thediameterofthe aortaeither at thetransverse archor atthe diaphragmistypicallyusedasan

ultimatetargetdiameter.Theaorticsegmentjustdistaltothecoarctationistypicallyaneurysmal,and oneshouldnotattempttomatchthisdiameter.

b. Aballoonthatisequaltoorjustslightlyshorterthantheselectedstentlengthshouldbeused.

c. TheNuMED BIB balloonis ideal for coarctation stent implant.Theouter balloon lengthshould

matchtheselectedstentlength.

4.Hand-crimping:

Thestentwillneedtobehand-crimpedontotheballoon.

a. The following techniques can be used to prevent the stent from slipping off the balloon during

advancementthroughthedeliverysheath:

i. Afterhand-crimpingthestent,alengthofumbilicaltapecanbeloopedaroundthestent/balloon

at its center and pulled tight to help tighten the stent down. This can be repeated a few millimetersfromeachendofthestentaswell.Oneshouldavoidtheendsofthestent,asthis techniquecancausethesharpendsofthestenttopuncturetheballoon.

ii. The balloon can be inflated to 0.5 atm prior to or immediately after introduction into the

deliverysheath.FortheNuMEDBIBballoon,theouterballoonshouldbeinflated.

b. Hand-crimpedstents shouldalwaysbe delivered totheir target vessel through a long sheath.The

sheathsizeshouldbe1-2Frenchsizeslargerthanthatneededfortheballooncatheteralone.

5.Itiscrucialtopositiontheshoulderoftheballoonproximaltotheoriginofwhicheversubclavianis

usedto anchor the guidewire. Failure to do so will cause the balloon to“milk”out of thesubclavian arteryduringinflationandwillresultinfailuretodeploystentinthedesiredlocation.

6.Inourpractice,ifthestenosisdoesnotresolveat≤5atmofpressure,wewillbringthepatientbackat

a second setting6-12 monthslater forfurther expansion.Thisprovides time forthe tissue toheal and

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mature,andoftenthelesionwillbecomemorecompliant.

7.Compliance:

When treating highly compliant lesions or lesions with only a mild amount of stenosis, rapid right ventricularpacingcanbe usedtodecreasecardiacoutputandaorticpulsepressure,therebyimproving balloonstabilityduringimplant.Thisisgenerallynotnecessaryintightstenoses.

a. Paceat180-200bpmwiththegoalofdecreasingthepulsepressureby10mmHganddecreasingthe

systolicBPto<100mmHg.

b. Pacing should be terminated after the delivery balloon is deflated to avoid a sudden change in

outputthatcouldforceapartiallyinflatedballoonthroughthestentanddislodgeit.

8.WhenusingaNuMEDBIBballoonforstentdelivery,anangiogramcanbeperformedeitherthrough

the delivery sheath or through an antegrade catheter to confirm the position of the stent prior to full expansion.

9.Aftertheballooncatheterisremoved,angiographycanbeperformedusingaMulti-Trackcatheterora

cutpigtailcatheteroverawire.

a. Assessforstentposition,size,andanyvascularcomplications

b. Repeatapullbacktoobtainapoststentgradient

10. Have inventory of large-diameter stents covered with polytetrafluoroethylene (PFTE) for use in

emergencysituations(seestentdiscussionintheprevioussection).

11.ProgradeCatheter:

Theuseofaprogradecatheterisreservedforspecialcases.

a. A prograde catheter froma radialorbrachial arterialaccesssitecanbe used toassistinballoon

positioning;tomonitorpressuresbefore,during,andafterthedilation;andforangiography.

i. Advantages: Allows for these measurements and angiography prior to obtaining arterial

access. Postprocedure, allows for angiography without requiring any manipulation of wires/cathetersacrossafreshlydilatedcoarctation.

b. Aprogradecathetercanalsobeusedfromavenousaccesssiteviaatransseptalapproach.

F.ComplicationsFromStentAngioplasty

1. Similar to balloon angioplasty, complications of transcatheter stenting ofaortic coarctation canbe

classifiedinto3categories:(1)technical,(2)aortic,and(3)peripheralvascular.

a. Technicalcomplicationsincludeissueswiththeequipmentorproceduraltechniqueandincludestent

migration,stentfracture,balloonrupture,andoverlapofbrachiocephalicvessels.Stentmigration canoccurbecauseofanimproperlysizedballoonorballoonrupture.

i. IntheCCISCstudy,4.8%ofcasesinvolvedstentmigrationwith64%ofthesecasesoccurring

withtheuseofoversizedballoons.25Stentfracturewasrareandoccurredin6outof588 patientsinthesamestudy.Balloonruptureoccurredin2.2%ofpatientsintheCCISCstudy, primarilywiththeuseofolderPalmaz8-seriesstents.Balloonrupturecanresultinother

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complicationsincludingaorticwallinjury,embolizationofballoonfragments,andstent migration.Althoughunintentionaloverlaporjailingofthebrachiocephalicvesselsmaybe viewedasacomplication,itisnotuncommontointentionallyjailsuchvessels—theleft subclavianarteryinparticular.Whenthisoccurswithabare-metalstent,thereistypically preservedflowintothevessel.Ifanappropriatestentischosen,thecelloverlyingthevessel origincanbedilatedtoreducemetalliccoverage.TheCCISCstudyfollowed61suchcases (bare-metalstents)withnoevidenceofhemodynamicissuesorembolicevents.

ii. However,whenusingacoveredstent,severalfactorsmustbeconsidered:(1)didthevessel

havenormalantegradeflowinitially;(2)istheresufficientcollateralflow—eitherthrough dilatedcollateralsorthroughtheCircleofWillis—toavoidcompromisingcerebralblood flow;(3)istheresufficientcollateralflowtoavoidsubclaviansteal.Consultationwitha vascularsurgeonisrecommended.Insomecases,asurgicalcarotid-subclavianbypasspriorto stentimplantationmaybewarranted.

b. Aorticwallinjuriesmayincludeintimaltears,aorticdissection,andaneurysmformation.Stent

angioplastyisgenerallybelievedtoresultinlessaorticwallinjurythanballoonangioplastyalone. Thisislikelybecausestentangioplastydoesnotrequireoverdistensionofthetissuebeyondthe intendeddiameter,andthestentprovidessupportfortheaorticwallitself.

i. TheCCISCreported1.3%instanceofangiographicevidenceofintimaltearswithtwocases

requiringfurtherintervention,oneatthetimeoftheprocedureandone10monthslater.

ii. Aorticdissectionisarare,butpotentiallyfatalcomplication.Thisspeakstotheimportanceof

pre-andpostinterventionangiographyandtheimportanceofmaintaininganinventoryof coveredstents,shouldsuchacomplicationarise.About1.5%ofcasesintheCCISCstudyhad aorticdissectionwith3requiringemergentsurgery.

iii. Similarly,aorticaneurysmsareararebutpotentiallydangerouscomplicationoccurringinabout

of13casesof160,followeduplongitudinallyintheCCISCstudy.25Theycanpresentlateand therefore,werecommendfollow-upimaging(MRIorCTorangiography)6monthsafterstent placement.

c. Peripheralvascularcomplicationsaresimilartothoseseenwithanycardiaccatheterizationwith

arterialaccessandincludecerebralvascularaccidents,peripheralemboli,andinjurytoaccess vessels.Inourexperience,arteriotomyclosuretechniquessuchas“preclosure”oftheaccesssite withthePerCloseProGlide(AbbottVascular,SantaClara,CA)canhelpreducepostprocedural bleedingandhematomaformationinappropriate-sizepatients.

V.Follow-up

Balloonangioplastyandstentangioplastyforaorticcoarctationareassociatedwithlowlong-termrisks forevolvingaorticwallinjuryincludingdissectionandaneurysmformation.Thusroutineimagingofthe aorta with either CTA or MRA is warranted. We recommend imaging be obtained 3-6 months after interventionor soonerifthereisparticular concern.Subsequenttothat,follow-upimaging isgenerally recommendedevery5years.

References

1.BeekmanIIIRH.Coarctationoftheaorta.In:MossandAdams’HeartDiseaseinInfants,Children,andAdolescents.7thed.

Philadelphia,PA:LippincottWilliams&Wilkins;2008.

2.ErbelR,AboyansV,BoileauC,etal.2014ESCguidelinesonthediagnosisandtreatmentofaorticdiseases.EurHeartJ.

2014;35(41):2873-2926.doi:10.1093/eurheartj/ehu281.

3.CampbellM.Naturalhistoryofcoarctationoftheaorta.BrHearJ.1970;32(5):633-640.

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31.08.202625 Мб0Книга_3745_Библиотеки_им_академика_М_И_Перельмана.pdf
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