incidence of filter slow flow in patient with acute...

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洛和会病院医学雑誌　Vol.30：86−91,2019

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Incidence of Filter Slow flow in Patient with Acute Coronary Syndrome Using Distal Protection Device

PhyoHtetOo¹,KoKoSoe¹,AyumuFujioka²,ToshihiroIwasaku²,TakeyaMinami²,HiroakiFujie²,NaofumiOyamada²,IchiroHamanaka²,KinzoUeda²

¹No.(2),DefenceServicesGeneralHospital,Naypyidaw,Myanmar²RakuwakaiKyotoCardiovascularInterventionCenter,RakuwakaiMarutamachiHospital

【Abstract】Aim: Effectiveness of distal protection device in primaryPCI has been controversial.Actually, in dailypracticewesometimesexperiencefilterslow-flowafterstentingandsometimesnot.Soweassumedthatthosecaseswhichfilterslowflowoccurredshouldbethesubsetswhichwouldreceivethebenefitsbyusingdistalprotectiondevicesforavoidingno-flow/slow-flowinACScircumstances.Method:Thesubjects consistedof 273consecutiveACSpatientswhounderwentprimaryPCIusingdistalprotectiondevice(Filtrap,NIPRO)betweenMay2009andJanuary2018.Theyweredivided into 2groupsdepending on the occurrence of filter slow-flowafter stenting; the filterslow-flow (FS)group (n=129)andno filter slow-flow (nFS)group (n=144).Patient’s characteristics, lesionandproceduralcharacteristicswereanalyzedbetweenthetwogroups.Results:Therewerenosignificantdifferencesinpatientcharacteristicsregardingcardiovascularriskfactors(Hypertension,Diabetes,HemodialysisandSmoking),exceptdyslipidemia(65.9%vs42.3%,p<0.01).Thetotalocclusion lesion on controlCAGwas significantly common inFSgroup thannFSgroup (69.8%vs 57.6%,p<0.05).Moreover, the largeamountof thrombusburden justafterwiringweremore likely found inFSgroupthannFSgroup(44.1%vs2.1%,p<0.01).Theexistenceofcalcificationandtortuosityof lesionwerefewerinFSgroupthannFSgroup(67.4%vs85.3%,p<0.01),whichshowedthelesionsinFSgrouphavemorefragileatherosclerosisor thrombus.Asaresult, aspiration thrombectomy justafterwiring (64.3%vs27.1%,p<0.01)andpredilatationprocedures(61.2%vs21.3%,p<0.01)werehigherinFSgroup.Conclusion:Theseresultsdemonstrate that the selectiveuseofdistalprotectiondevice in the fragileandhighthrombusburdenlesionwhicharemorelikelyfoundinFSgroupisthekeytoavoidslowflow/noreflowphenomenonandseriousadversecardiaceventsafterrevascularization.

【Introduction】

　　Itisevidentthattheoccurrenceofdistalembolization

and associated slow-flow/no-reflowphenomenon after

percutaneous coronary intervention (PCI) for acute

coronary syndrome (ACS) result in poor prognosis.

However, theeffectivenessofdistalprotectiondevice in

primaryPCIhasbeen controversial.Actually, in daily

practicewesometimesexperience filter slow-flowafter

stentingandsometimesnot.Soweassumed that those

caseswhichfilterslowflowoccurredshouldbethesubsets

whichwillreceivethebenefits foravoidingno-flow/slow-

flowinACSrecanalizationtreatment.

【Methods】

Study Population

　　BetweenMay2009andJanuary2018,273consecutive

ACSpatientswhounderwentprimaryPCIusingdistal

protectiondevice (Filtrap,NIPRO)wereenrolled in this

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study.Theyweredividedinto2groupsdependingonthe

occurrenceoffilterslow-flowafterstenting:thefilterslow-

flow(FS)group(n=129)andnofilterslow-flow(nFS)group

(n=144).

Procedures

　　Weretrospectivelyanalyzedthepatient’sclinicaldata,

procedures andangiographic findingsby twodifferent

observers.All patientswere pre-medicated 200mg of

aspirinandbolus injectionof5000IUheparinatERand

5000IUofheparin intracoronaryof theculpritvesselat

controlCAG. Inaddition,allpatientswereprescribeda

loadingdoseofClopidogrelorPrasugrelatER.PCIwas

performedaccording to thestandardclinical techniques

withradialor femoralarteryapproaches. Culprit lesions

wereclassifiedaccordingtotheAHA/ACCclassification.

Severityoflesionstenosiswasdividedintothreecategories

according topercentageof stenosisoncontrolCAG: (1)

Mild;stenosis<75%(2)Moderate;Stenosisbetween75and

99% (3)Severe; stenosis>99%orTotalocclusion lesion.

Thrombusburdenwasdefinedas: (1) Small;Only intra

luminal staining (2)Moderate;Other fillingdefectsnot

associatedwithcalcification, lesionhaziness, irregularity

withill-definedborders(3)Large;Intraluminal,roundfilling

defect,visibleintwoviews,largelyseparatedfromvessel

wall.Severityofcalcificationwascategorizedas: (1)Mild;

Arterialwallcalcificationseenas thin line (2)Moderate;

fillingdefect in lesionnotassociatedwiththrombusseen

evenbeforeandaftercontrast injection (3)Severe;heavy

easily seen calcification.Target lesion tortuositywas

definedas (1)Mild;straightsegmentoronlyonebendof

60degreeormore (2)Moderate; twobendsof60degree

ormore (3)Severe; threeormorebendsof60degreeor

more. Intra-arterial flowwasgradedas0-3according to

theThrombolysis inMyocardial Infarction trial (TIMI)

classification.Collateral flowwasgraded according to

Rentrop’sscore.Afterthecontrolangiogram,7Frguiding

catheterwasused forall of thepatients, and the lesion

wascrossedwith0.014 inch floppyguidewire.Usageof

thrombus aspirationprocedurewasdepended on each

operator’s choice.Thenwe evaluated IVUS findings

inmost cases except fromhemodynamically unstable

patients. In severe organic stenotic or calcified lesions

dilatationbyballoon(<3mm)wasadded.Accordingtothe

IVUS findingandangiographic information, theoperator

deployedFiltrap.Thenweimplantedadrug-elutingstent.

The Basic Principle of Filtrap

　　Details ofFiltrap (NIPRO, Japan)havealreadybeen

describedelsewhere. Inbrief, the filter isattachedto the

distalendofa0.014-inchguidewire.The filtermembrane

isattachedtohalfofthefilterbasket.Thefiltermembrane

ismadeofpolyurethaneandhasapproximately1800holes.

Eachholesizeisapproximately100μm,andthemembrane

is40μmthick.

Statistical Analysis

　　SPSSversion21.0(SPSSInc.,Chicago,IL)wasusedfor

allanalyses.Categoricaldatawasexpressedasabsolute

frequenciesandpercentage.Thedatewascomparedusing

aChiSquare testorFisher’sexact test, asappropriate.

Continuousvariables,whichareexpressedasthemean±

standarddeviation (SD),werecomparedusingeitheran

unpairedStudent’st-testortheMann-WhitneyUtest.Ap

valueof<0.05wasconsideredstaticallysignificant.

【Results】

Baseline Demographic

　　Filter slow-flowoccurred in129patients (Table1).

Although therewereno significantdifferences inother

basicbackgroundofpatient’scharacteristicbetweentwo

groups, patients in theFSgroup showed significantly

higherLDLcholesterollevelatadmissionthanthoseinthe

n-FSgroup.

Lesion Characteristics

　　Themorphological characteristics of the lesions in

twogroupsareshowninTable2andTable3.Asforpre-

IncidenceofFilterSlowflowinPatientwithAcuteCoronarySyndromeUsingDistalProtectionDevice

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proceduralangiographicfinding,target lesionsweremore

commoninRCAandLADthanLCXandtargetsegment

weredetected inproximalandmidsegmentsmorethan

distal segments,whichwerenosignificantdifferences in

bothgroups.Regarding the lesion characteristics, total

occlusionlesiononcontrolCAGwascommoninFSgroup

thannFSgroup(69.8%vs57.6%,p<0.05).Inaddition,the

FSgrouphad significantly larger amount of thrombus

burdenjustafterwiringcomparedwithnFSgroup(44.1%

vs2.1%,p<0.01).InFSgroup,mildcalcifiedlesionswere

significantlyhigher thannFSgroup (85.3%vs 67.4%,p

<0.001).On theotherhand, the lesionswithmoderate

calcification inFSgroupwere less thannFSgroup (9.3%

vs22.9%,p<0.01)

Variable Total(n = 273)

FS group(n= 129)

n-FS group(n= 144) P value

Age (years) 70.2 ±12.1 70.1±11.9 70.3±12.3 0.89

Males 213(78.1%) 105(81.3%) 108(75.2%) 0.24

Hypertension 175(64.1%) 78(60.1%) 97(67.2%) 0.25

Diabetes Mellitus 101(37.0%) 51(40.3%) 50(35.1%) 0.45

Smoking 132(48.4%) 62(48.1%) 70(49.3%) 1.00

Hemodialysis 10(3.7%) 3(2.1%) 7(5.3%) 0.34

Dyslipidemia 80(29.3%) 51(65.9%) 29(42.3%) <0.01*

Systolic Blood ressure (mmHg) 146.7±29.3 144.1±29.7 149.1±28.8 0.53

LVEF (%) 53.8±12.2 51.7±11.6 55.7±12.6 0.12


FS group(n= 129)


Lesion Location

LAD 120(43.1%) 58(45.1%) 62(43.4%) 1.00

LCX 14(5.1%) 6(4.8%) 8(5.2%) 0.41

RCA 139(51.2%) 65(50.1%) 74(51.4%) 0.76

Target Lesion Segment

Proximal(Seg.1, 5, 6, 11) 147(53.8%) 71(55.0%) 76(52.8%) 1.20

Mid(Seg.2, 7, 9, 12, 13) 115(41.1%) 52(40.4%) 63(43.8%) 1.21

Distal(Seg.3, 4, 8) 11(4.1%) 6(4.6%) 5(3.4%) 1.00

Table 1. Baseline patient characteristics

Table 2. Pre-procedural morphological characteristics of target vessels

Continuous data is presented as mean ± standard deviation; categorical data is presented as a number (%) LVEF left ventricular ejection fraction

Categorical data is presented as a number (%)

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Procedural Characteristics

　　Regardingproceduralcharacteristics, therewereno

significantdifferences inpredilatationballoonsize (2.8±

0.6mmvs2.9±0.5mm,p=0.54),stentdiameter (3.4±0.4

mmvs3.4±0.3mm,p=1.0)andstentlength(25.1±7.0mm

vs24.4±6.4mm,p=0.23)betweenbothgroups. (Table4)

Moreover,therewasalsonosignificantdifferenceinsingle

stent procedure (75.9%vs 82.7%, p=0.24) andmultiple

stentprocedure (24.1%vs17.3%,p=0.45)betweenboth

groups (Table 4).The rate of thrombusaspiration just

afterwiringweresignificantlyhigher inFSgroup than

nFSgroup(64.3%vs27.1%,p<0.01).Inaddition,therateof

predilatationwithballoon(POBA)wassignificantlyhigher

inFSgroupthannFSgroup(61.2%vs24.3%,p<0.01).

【Discussion】

　　Incomparisonwith lesions found instablecoronary

arterydiseases, coronary lesions responsible for acute

coronarysyndromes (ACS)consistsofdisruptedplaques

with superimposed thrombus, and disrupted plaques

which tend to have larger necrotic cores andgreater

plaque inflammation (1).Distalembolizationof thrombus

or atheromatous gruel from epicardial culprit lesion

is common inACSandmightbe further triggeredby

percutaneouscoronary interventions (PCIs) (2,3).Factors

thatincreasetheriskofdistalembolizationwhichinturn

manifestas slow/noreflowphenomenon includePCI to

lesions containing large amounts of friable atheroma,

PCI to culprit lesions containing thrombus responsible

forACS,anduseofatherectomy. (4-6).Accordingtothis

study, thepatientswithdyslipidemiawerehigher inFS

group. So thesepatientshadmore chance of slow/no

flowafterprocedureforACS.Inthelesioncharacteristics,

total occlusion lesion on controlCAGand lesionwith


FS group(n= 129)


% Stenosis Control CAG

<75% 46(17.0%) 16(12.4%) 30(20.1%) 0.17

75-99% 54(19.7%) 23(17.8%) 31(22.2%) 0.33

100% 173(63.3%) 90(69.8%) 83(57.6%) <0.05

Thrombus Burden just after wiring

Small 150(55.0%) 45(34.9%) 105(72.9%) <0.01

Moderate 63 (23.1%) 27(21.0%) 36(25.0%) 0.42

Large 60 (21.9%) 57(44.1%) 3(2.1%) <0.01

Calcification

Mild 207(75.8%) 110(85.3%) 97(67.4%) <0.001

Moderate 45(16.5%) 12(9.3%) 33(22.9%) <0.01

Severe 21(7.7%) 7(5.4%) 14(9.7%) 0.33

Target Lesion Tortuosity

Mild 178(65.2%) 75(58.1%) 103(71.5%) <0.05

Moderate 60(21.9%) 39(30.2%) 21(14.6%) <0.05

Severe 35(12.8%) 15(11.6%) 20(13.9%) 1.00

Table 3. Lesion characteristic on CAG

Continuous data is presented as mean ± standard deviation; categorical data is presented as a number (%)

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原　著

large thrombusburden justafterwiringwerehigher in

FSgroup thannFSgroup. Inaddition, theexistenceof

calcificationand tortuosityof lesionswere fewer inFS

groupthannFSgroup.Theseresults indicatethe lesions

inFS group have fragilemassive atherosclerosis and

thrombus.Asresult, aspiration thrombectomy justafter

wiringandpredilatationproceduresbyPOBAwereused

frequentlyinFSgroup.

Theeffectivenessofdistalprotectiondevice inprimary

PCIhasbeencontroversialso far.That isbecausethose

populationhavewidevariationsinbothpatientbackground

andlesioncharacterbackground.So,weneedtoselectthe

patientswhowouldgetmorebenefitofdistalprotection

device.Our studywas retrospective study fromsingle

centerexperience,howeveritcouldbeamilestoneforthe

beneficialuseofdistalprotectiondevicesinprimaryPCI.

【Limitations】

　　Thisstudyhasseveralpotentiallimitations.Firstthis

studywasa retrospective single-centerexperience ina

limitednumberofpatients. Second,wecannot analyze

lesionsmorphologiesinallpatientsbyIVUSstudybecause

ofhemodynamic instability in somepatients.However,

even under these conditions,we can exhibit that the

fragileatherosclerosis, totallyoccluded lesionsand large

thrombusburden lesions indyslipidemiapatientswere

associatedwithhigh frequencyoffilterslowflowduring

theprocedure.

【Conclusion】

　　This studydemonstrated thepatients, lesions and

proceduralcharacteristics that increasetheriskofdistal

embolization bymean of filter slow flow. So, selected

use of distal protection device in these patients and

lesioncategoriesare importantduringrevascularization

procedureinprimaryPCI.

【Acknowledgments】

　　Apartofthisworkwaspresentedatthe27thAnnual

Meetingof the JapaneseAssociation ofCardiovascular

InterventionandTherapeutics.

【Conflicts of Interest】

　　The authors report no financial relationships or

conflictsofinterestregardingthecontentherein.


FS group(n= 129)


Predilatation balloon size(mm) 2.9±0.5 2.8±0.6 2.9±0.5 0.54

Stent diameter (mm) 3.4±0.4 3.4±0.4 3.4±0.4 1.00

Stent Length(mm) 24.8±19.4 25.1±7.0 24.4±6.4 0.23

Number of Stent

One stent 217(79.4%) 98(75.9%) 119(82.7%) 0.24

Two or More Stents 56(20.6%) 31(24.1%) 25(17.3%) 0.45

Aspiration Thrombectomy Just after wiring 122(44.6%) 83(64.3%) 39(27.1%) <0.01

Predilatation (POBA) 114(41.7%) 79(61.2%) 35(24.3%) <0.01

Table 4.Procedural Characteristics

Continuous data is presented as mean ± standard deviation; categorical data is presented as a number (%)

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