I N N OV ATI ON S
A t e ch n ica l a lt e r n a t ive for t h e e n dova scu la r t r e a t m e n t of poplit e a l a r t e r y
a n e u r ysm s
M a r ce lo Fe r r e ir a ,I Ale x a n dr e M e de ir os,I I M a r ce lo M on t e ir o,I Lu iz La n z iot t iI IMD. Servi€o Integrado de T•cnicas Endovasculares (SITE), Rio de Janeiro, RJ, Brazil.
IIResident, Hospital dos Servidores do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Correspondence
J Vasc Bras. 2008;7(1):44-8.
ABSTRACT
Popliteal artery aneurysm is relatively rare, but represents around 85% of all peripheral arterial aneurysms. It is usually presented with ischemic complication and high risk of limb loss. For that reason, its elective treatment is indicated and currently carried through with satisfactory results using endovascular techniques. We describe our experience with the use of an ePTFE-covered nitinol self-expandable stent graft - Fluency (Bard, Germany), reinforced internally with the nitinol self-expandable Zilver stent (Cook, USA) for the treatment of a popliteal artery aneurism.
Ke y w or ds:Aneurysm, popliteal, endovascular technique.
RESUM O
O aneurisma de art•ria popl‚tea • relativamente raro, por•m representa cerca de 85% de todos os aneurismas arteriais perif•ricos. Apresenta-se geralmente com um quadro de complica€ƒo
isqu„mica e elevado risco de perda do membro acometido. Em fun€ƒo disso, preconiza-se seu tratamento eletivo, atualmente realizado com resultados satisfat…rios pela t•cnica endovascular. Relatamos nossa experi„ncia com a utiliza€ƒo do stent de nitinol auto-expans‚vel revestido com PTFEe – Fluency (Bard, Alemanha), refor€ado internamente com o stent de nitinol auto-expans‚vel Zilver (Cook, EUA) no tratamento de um aneurisma de art•ria popl‚tea.
I n t r odu ct ion
Aneurysm al disease of t he poplit eal art ery is relat ively rare, but it account s for about 85% of all peripheral art erial aneur ysm s.1 High r at es of t hr om boem bolic com plicat ions, oft en being it s first m anifest at ion, grant it a significant r isk of lim b loss and vascular bed dest r uct ion. For t hat reason, surgical t reat m ent is cur r ent ly r ecom m ended for aneur ysm s larger t han 2 cm .2 Despit e t hat fact ,
surgical indicat ion based on aneurysm diam et er is st ill cont roversial. Som e r ecom m end clinical follow- up for t hose up t o 3 cm in diam et er , but , on t he ot her hand, som e are m or e focused on sm aller aneur ysm s ( < 2 cm ) , but pr esent ing int ralum inal t hr om bi or sym pt om s of
m icroem bolizat ion, claim ing t hat t hey should be repaired due t o a high risk of ischem ic com plicat ions.3
At herosclerosis, w hich pr obably has m ult ifact or ial or igin, seem s t o be t he m ain cause in t he elderly.4
Poplit eal art ery aneur ysm is t he m ost com m on per ipher al aneur ysm . I t s pr evalence is 1% in t he general populat ion, and it is oft en bilat eral. Occurrence of associat ed aneur ysm s in ot her sit es is obser ved in 35% of pat ient s, w it h pr evalence for t he abdom inal aort a, ranging bet w een 27- 50% in t he lit erat ure. Ther e are r epor t s st at ing t hat such associat ion is m or e frequent in pat ient s w it h bilat eral poplit eal aneurysm , r eaching up t o 70% .5
I n asym pt om at ic pat ient s, 14- 24% develop sym pt om s over a 1- year per iod, and acut e ischem ia is t he first sy m pt om in 20- 50% of cases. I n 5 years, unt r eat ed aneur ysm s w ill have com plicat ions in 70% of cases, leading t o lim b loss in 30- 40% .6
As t o rupt ure, a review of MEDLI NE and LI LACS dat a bet w een 1953 and 2003 found a t ot al of 4,109 poplit eal art ery aneur ysm s, 120 being r upt ur ed ( 2.92% ) .7
There are t w o hist or ic landm ar ks in t he sur gical t reat m ent of poplit eal aneur ysm s: t he fir st , ar ound 1785, w hen Desaut , in Fr ance, and Hunt er , in England, proposed ligat ion of t he super ficial fem or al art ery in t he adduct or canal, inaugur at ing t he so- called Hunt erian era of poplit eal aneur ysm
surgery. That t echnique result ed in 10.5% of cases pr ogr essing w it h lim b gangr ene. And t he second, w hen Mat as, in 1888, developed t he t echnique of endoaneur ysm or r aphy, only published in 1903, w hich pr im ar ily aim ed at pr eser ving collat er al circulat ion. That m et hod caused a 5.2% reduct ion in am put at ion r at e. Lum bar sym pat hect om y before endoaneur ysm or r aphy pr oposed by Bird and adopt ed and r ecom m ended by Lint on also show ed im pr ovem ent in result s regarding lim b loss.5
Wit h t he advent of t he m odern age of art erial surgery, poplit eal aneur ysm s st art ed being t reat ed by r esect ion of t he aneurysm al sac and reest ablishm ent of art erial cont inuit y, using aut ogenous vein or st ent graft as ar t er ial subst it ut es. I n 1969, w it h t he aim of sim plifying t his sur ger y,
Edw ards int roduced t he t echnique of aneurysm exclusion by ar t er ial ligat ions perform ed above and below it , w it h r eest ablishm ent of cir culat ion t hr ough a by pass graft , being t he first choice of m any vascular sur geons, w it h success rat e of 90% or m or e.8 , 9 Mor e r ecent st udies by som e r enow n
cent ers have claim ed t hat post er ior approach w it h gr aft int er posit ion could br ing ev en bet t er result s.1 0 , 1 1
Throughout t hese year s, t reat m ent of t his pat hology oscillat ed bet w een st ages of ext rem e int erest and ot hers m arked by a lack of r esear ch and m edical innovat ions. Since 1994, w hen t he first endovascular t reat m ent w as r epor t ed by Mar in et al.,6 w ho used a st ent gr aft pr oduced based on
t he sut ur e of t w o Palm az st ent s inside a 6- m m PTFEe, again placed on an angioplast y balloon, it has once again becom e an issue, ev en w it h report s of bilat er al t r eat m ent , such as t hat by Medeir os & Gaspar .1 2
Ca se r e por t
A 78- year - old m ale pat ient , Caucasian, w it h hyper t ension and dyslipidem ia, previously subm it t ed t o bilat er al car ot id art ery endar t er ect om y and w it h concom it ant abdom inal aor t ic aneur ysm sm aller t han 5 cm . On physical exam inat ion, t here w er e asym pt om at ic pulsat ile m asses in poplit eal
t opographies. Angiogr aphic t om ogr aphy w as r equest ed, confir m ing pr esence of bilat er al poplit eal art ery aneurysm (Figure 1) .
The t echnique consist ed of:
1.Ant erograde punct ure of t he ipsilat eral com m on fem or al art ery, exposed by dissect ion.
2.I nt roduct ion of a 9Fr 27- cm sheat h ( Cook, USA) .
3.Angiography w it h digit al subt r act ion (Figure 1A) .
4.I m plant at ion of cover ed Fluency st ent s, one 8x 80 m m dist al and one 9x80 m m pr oxim al, w it h an
overlap of appr oxim at ely 3 cm .
5.I m plant at ion of t w o Zilver 8x80 m m st ent s int er nally, w it h an overlap of 1 cm , ext ending for about 1 cm beyond dist al and proxim al ends of cover ed st ent s.
Cont rol angiogr aphic t om ogr aphy on t he 7t h post operat ive ( PO) day show ed t ot al aneurysm exclusion and gr aft pat ency w it h proper placem ent . Angio- CT aft er 2 m ont hs confir m s good out com e.
D iscu ssion
Endovascular t r eat m ent requires special at t ent ion for som e anat om ic det ails. Som e st udies based on ult r asound assessm ent s est im at ed m ean diam et er of t he nor m al poplit eal art ery r anging
bet w een 0.90± 0.11 cm , w hile ot her aut hor s r epor t ed sm aller diam et ers, r anging bet w een 0.47- 1.1 cm .3
Mean diam et er of t he nor m al poplit eal art ery is lar ger in m en, and in bot h genders it s diam et er is not unifor m ; proxim al and m edial poplit eal ar t er ies ar e sim ilar and t he dist al poplit eal art ery is sm aller.3 I n a st udy by Cur y et al. including 27 m en w it h 45 pat ent fusifor m aneur ysm s, t he m edial
Dist al poplit eal art ery w as not t he sit e of higher dilat at ion in any case, and it had diam et er > 10 m m in only one.2
The first published ar t icles r epor t ed use of Wallgr aft ( Bost on Scient ific, USA) as an endovascular alt ernat ive for poplit eal art ery aneur ysm s. Due t o it s design, based on Wallst ent ( Bost on Scient ific, USA) , it w as subj ect t o shor t ening/ w idening accor ding t o vessel caliber . Such char act er ist ic m ade it s placem ent im precise, m aking it s connect ions unst able, especially in t he ret ropat ellar ar ea, subj ect t o int ense m ovem ent s, especially flexion. How ell et al., in 13 cases using t hat graft , obser ved t hr om bosis in 31% of cases in 12 m ont hs.1 3
Wit h t he int r oduct ion of ePTFE- cover ed nit inol st ent s, such as Viabahn ( Gor e, USA) , int erest on t his t herapeut ic opt ion w as once again renew ed. Since Viabahn has m or e flexibilit y and is subj ect t o a low er shor t ening/ w idening effect t han Wallst ent ( Bost on Scient ific, USA) , it has bet t er r esult s in areas cont aining folds and m uch k nee m ovem ent . Tielliu et al., in 57 cases using Viabahn ( Gor e, USA) , had t echnical success in 100% of cases, w it h pr im ar y and secondar y pat ency in 2 year s of 77 and 87% , r espect ively. Acut e ischem ia at int ervent ion w as pr esent in 9% of cases.1 4 , 1 5
Despit e pr om ising init ial r esult s using t his device, use of Viabahn st ent graft ( Gore, USA) had t he disadvant age of not assim ilat ing ext ernal com pressions (Figure 3A) . Consider ing t he conical shape of t he nor m al poplit eal art ery ( 2- 4 m m difference bet w een proxim al and dist al diam et ers) , w hich is exacer bat ed w hen t here is an aneur ysm in it s pr oxim al and m edial segm ent s, t her e m ay be an incom plet e expansion of t he Viabahn ( Gore, USA) dist al segm ent , w it h consequent clam ping of t he device (Figure 3B) and likely occur r ence of t ype I B leakage, w hich w ould m aint ain blood flow inside t he aneur ysm al sac, as w ell as for m at ion of an ir r egular int er nal bed, causing em bolic
Considering endovascular devices current ly available in t he m ar ket , a feasible alt ernat ive is using t he cover ed Fluency st ent ( Bar d, Ger m any) , associat ed w it h use of self- expandable Zilver st ent ( Cook, USA) inside t he cover ed Fluency st ent , and advancing 1 cm beyond it s ends, w it h t he aim of st abilizing j unct ion bet w een cover ed st ent s and avoiding t heir kinking w hen subm it t ed t o k nee flexion for ces.
We believe t he follow ing are advant ages of t he proposed opt ion:
1.The ePTFE- cover ed nit inol Fluency st ent ( Bard, Ger m any) does not have t he phenom enon of shor t ening and w idening, m aking it s im plant at ion m or e pr ecise in t he poplit eal art ery.
2.Clam ping result ing from irregularit y in poplit eal art ery diam et er is reduced, since t he design of t he Fluency st ent allow s bet t er placem ent using st ent s of varied diam et ers, besides per for m ing a self- expandable Zilver st ent , w hich has m or e radial force, int ernally t o t he cover ed st ent ,
reinforcing sealing and prevent ing occurrence of device kinking.
3.Chance of disconnect ion of cover ed st ent s as a consequence of repet it ive m ovem ent of t he ret ropat ellar t errit ory, as w ell as t he possibilit y of t er m inal poplit eal art ery rect ificat ion during knee flexion m ovem ent s, are solved by placing a self- expandable st ent inside it , advancing 1 cm bey ond t he ends. This r esult s in a final gr aft w it h good flexibilit y, avoiding folds or fr act ur es, besides ensuring bet t er fixat ion and a st able union bet w een cover ed st ent s.
As negat ive point s, w e can m ent ion t he need of device over lapping, especially over t he j oint line. Unt il t he case w as perform ed, t he largest lengt h available for t he cover ed Fluency st ent w as 8 cm , w hich caused lim it at ion due t o t he t endency of using m or e st ent s. Models of t hat st ent m easur ing up t o 12 cm in lengt h have been r ecent ly launched in t he Br azilian m ar ket , w hich reduces such lim it at ion.
Good out com e report ed in t his case, alt hough in t he short t erm , dr aw s at t ent ion t o t he possibilit y of using t he cover ed Fluency st ent associat ed w it h int ernal reinforcem ent w it h self- expandable st ent in t he t reat m ent of poplit eal art ery aneur ysm s.
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Cor r e spon de n ce : Marcelo Ferreira
Rua Siqueira Campos 59/203, Copacabana CEP 22031-070 – Rio de Janeiro, RJ, Brazil Tel.: (21) 2236.1637
Email: mmvf@uol.com.br
