Superficial
femoral artery recanalization with Zilver stents: standard technique and 3-year
retrospective analysis
(Portuguese
PDF version)
Marcelo
Ferreira, Luis Fernando Capotorto, Giafar Abuhadba, Marcelo
Monteiro, Luiz Lanziotti * *
Serviço Integrado de Técnicas Endovasculares (SITE), Rio de Janeiro,
RJ, Brazil. Correspondence:
Marcelo Ferreira
Rua Siqueira Campos 59/203 - Copacabana
CEP 22031-070 -
Rio de Janeiro, RJ, Brazil
Tel.: 55 21 2236.1637
E-mail: mmvf@uol.com.br
ABSTRACT Objectives:
To describe the endovascular recanalization technique of the superficial femoral
artery and perform a 3-year retrospective analysis of the technique. Methods:
Retrospective analysis of the patients treated between 2001 and 2004, with the
aim of obtaining the patency rates of the recanalizations. The sample consisted
of 79 recanalized superficial femoral arteries in 61 patients, exclusively using
the described technique and the same nitinol self-expanding stent model (Zilver,
COOK). Results: Of the 61 patients,
8% had critical lower limb ischemia and 92% had incapacitating claudication refractory
to the clinical treatment. Clinical improvement was observed and reported by the
patients in a direct correlation with the recanalization patency. The statistical
analysis showed accumulated assisted primary patency rates of 98, 91 and 84% in
12, 24 and 37 months, respectively. The patency rates, considered as the continuous
flow in the treated area, were 96, 93 and 93% in 12, 24 and 37 months, respectively. Conclusions:
We consider the recanalization technique of the superficial femoral artery a less
invasive method, with few complications and considerable anatomic success and
patency rates, which are able of promoting satisfaction and quality of life to
patients with peripheral obstructive arterial disease.
Keywords:
Femoral artery, angioplasty, stents, intermittent
claudication.
J
Vasc Bras. 2006;5(4):263-70 Article
submitted July 21, 2006, accepted December 18, 2006.
INTRODUCTION
The last decade of the 20th century
was certainly the golden age of endovascular surgery, now reaching the precise
repair of several arterial diseases, some allowing the treatment of high-risk
patients, who cannot undergo conventional surgery. Great part of that technical
evolution is due to the creation and constant enhancement of angioplasty balloons
and intravascular stents. Since 1994, when intracoronary balloon-expandable stents
were approved by the Food and Drug Administration (FDA), those devices have been
widely used. Today, they present satisfactory results in the treatment of coronary
atherosclerotic disease,1-5 and have also been used
in the superficial femoral artery (SFA).6 After
balloon angioplasty, it is essential to understand the occurrence of four factors:
formation of thrombi, intimal hyperplasia, negative remodeling and recoil effect.
Stents are able to eliminate, due to their radial force, those two latter factors.7,8
Formation of thrombi is preventively treated using platelet antiaggregating agents
and anticoagulants. Intimal hyperplasia has been successfully treated in the coronary
territory by using drug-releasing stents, which, in the femoral territory, are
being submitted to an international multi-centered trial. Intimal hyperplasia
basically consists of the proliferation of smooth muscle cells and deposition
of extracellular matrix, in response to the lesion caused by angioplasty and presence
of stent.9-12 An
important factor in the prevention of occlusion or recurrent stenosis is the structure
of stents, based on many factors, such as release mechanism, material used for
manufacturing, presence of polymers and/or other substances able to induce local
inflammation and others, called mechanic factors. Recurrent stenosis induced by
mechanic factors has been controlled due to constant advances in new devices at
each generation;9-12 many authors, such as Henry6
and Scheinert,13 confirmed the differences even in
different models of nitinol self-expandable stents.
METHODS
In 2001, after initial cases of endovascular
revascularization of lower limbs, we standardized a technique to be used in SFA
and popliteal artery recanalization, which became our first choice in the treatment
of all patients with peripheral obstructive arterial disease (POAD), incapacitating
claudication and critical ischemia of the lower limb, without clinical therapeutic
success. The diagnostic of POAD was
performed using Doppler and clinical examination in most cases. In the postoperative
period, the patients are submitted to Doppler ultrasonography every 6 months,
or before that, in case of clinical worsening. Superficial
femoral artery recanalization (technique standardized by SITE) 1)
Contralateral retrograde femoral puncture. 2)
Introduction of a 5 F sheath. 3) Placement
of catheter with black tip mammary curve over a 0.035 x 260 cm hydrophilic guide
wire (Road Runner®, COOK) for catheterization of the contralateral iliac artery. 4)
Advancement of that catheter and guide until the contralateral femoral bifurcation,
where the guide is replaced by a 0.035 x 260 cm Amplatz stiff wire guide to support
the replacement of the short 5 F sheath by a wired long 55 cm 6 F sheath(Raabe®,
COOK). 5) Again, the hydrophilic guide
and the mammary curve catheter are inserted through the 55-cm sheath and gently
advanced toward the SFA, until reaching the true lumen of the distal popliteal
artery. In some cases, they pass through a subintimal path, but not necessarily
(Figures 1A and 1B); when the guide reaches the distal portion of the popliteal
artery, the hydrophilic guide is replaced by the Amplatz guide to provide more
support and advance the sheath until the SFA.  Figure
1 - A) Initial arteriography showing right superficial femoral artery occluded
at its origin; B) guide wire inserted in the superficial femoral artery to be
recanalized; C) control angiography after angioplasty
6)
Being careful to maintain the guide in position, the catheter is removed and replaced
by a 6 mm x 10 cm balloon (Pursuit®, COOK), which will be inflated to about
8 atm in all the extension of the recanalized artery for 3 min. 7)
Once again, maintaining the guide in position, the balloon is removed and all
the recanalized area is recovered with stents, being careful to perform an overlapping
of at least 10 mm between stents to make all areas between stents remain covered,
serving as a stimulus to recurrent stenosis (Figure 2). Figure
2 - A, B) Aspect after stent angioplasty; C) control angiography 
8)
After angiographic control, if necessary, dilatation is repeated using the same
balloon; next, the whole material is removed, followed by percutaneous arterial
sealing (Figure 3). Figure
3 - A) Preoperative tomography angiography; B) control after right superficial
femoral artery recanalization; C) control after left superficial femoral artery
recanalization (note in B and C the branches originated from the recanalized territory) 
In
the postoperative clinical treatment, we used the drug regime of continuous acetylsalicylic
acid at 325 mg/day, associated with clopidogrel at 75 mg/day for at least 6 months,
aiming to combat the formation of thrombi. Postoperative
control using duplex scan in 30 days and every 6 months thereafter is performed
to follow patency and detect possible recurrent stenoses, besides radiography
to detect fractures. Patients The
sample consisted of 79 recanalized SFA in 61 patients, exclusively using the described
technique and the same nitinol self-expanding stent model (Zilver, COOK). Excluded
patients were those without proper clinical follow-up and those who used other
models of stents or techniques. Seven patients (eight SFA) died in the follow-up
period, none of them due to the treatment under discussion, and all maintained
primary patency. Statistical
analysis Retrospective analysis
of the patients treated between 2001 and 2004, with the aim of obtaining the patency
and assisted primary patency rates of the recanalizations. The study was limited
to 12/31/2004, and the patients were divided into two groups: Group 1, considering
the cases in which there was primary patency or assisted primary patency, when
stenoses > 50% or clinical worsening were detected; Group 2, considering the
cases of stent occlusion, with absence of continuous flow in the treated area,
which reveals the patency rate of recanalizations. In these patients, arterial
bypasses, limb amputations or even clinical treatment were used to treat stent
thrombosis. For the statistical analysis,
the Kaplan-Meier method was used to calculate accumulated and survival probabilities,
and the SPSS software was used to estimate survival curves. The results were reported
according to the standards recommended by the Journal of Vascular Interventional
Radiology for clinical evaluation of peripheral revascularization devices.14
RESULTS
Of the 61 patients, 8% had critical lower limb
ischemia and 92% had incapacitating claudication refractory to the clinical treatment.
Demography also showed that 63% were male, 36% had diabetes, 55% were hypertensive
and 72% reported current or previous smoking. Around 20% of patients could be
classified as A and B in the TASC classification, and the others as C and D. The
immediate results were satisfactory, with 100% anatomical success in the recanalizations. Clinical
improvement in incapacitating claudication was observed and reported by the patients
in a direct correlation with the recanalization patency. Mean
follow-up time was 20 months (ranging between 0 and 37 months). There was only
one case of acute thrombosis, on the third postoperative day, and 50% of patients
presented more than 21 months of follow-up (P50 = 21 months), according to the
survival histogram (Figure 4). Figure
4 - Distribution histogram of the cases followed (in months) (P25 = 15, P50
= 21, P75 = 28; mean = 20.72; median = 21 months) 
Within
a 37-month horizon, around 10% of the sample (n = 7) presented hemodynamically
significant recurrent stenosis, with severe obstruction (> 50% at Doppler)
of the recanalized arterial lumen. These patients were submitted to a second endovascular
procedure, which assured a continuous assisted primary anatomical success in all
cases. Out of seven recurrent stenoses,
one occurred in month zero, another after 7 months and all others after 18 months,
requiring only one more procedure in all cases. Using the survival curve, we obtained
accumulated assisted primary patency rates of 98, 91 and 84% in 12, 24 and 37
months, respectively. (Figure 5). Figure
5 - Accumulated assisted primary patency over a 37-month period between 2001
and 2004, according to Kaplan-Meier's method 
The
distribution of recurrent stenosis cases showed that 75% (n = 5) of cases occurred
between 19-27 months of follow-up, whereas the others occurred up to the seventh
month (Figure 6). Figure
6 - Distribution histogram of recurrent stenosis occurrences over the evaluation
period 
The
patients who had stent thrombosis in SFA and untreated popliteal recanalizations
via endovascular represented about 7% of the sample (n = 5). There was one occlusion
in month zero, two in the fifth month and two in the 14th month of
follow-up. The survival curve in relation to this group (Figure 7) demonstrated
that, over the 37 months of follow-up, patency rates, understood here as presence
of continuous blood flow in the recanalized tract, were 96, 93 and 93% in 12,
24 and 37 months, respectively. Of these five cases, two underwent saphenous vein
arterial bypass, two had amputation of the recanalized limb and one is still under
clinical treatment, after the lesions that indicated initial treatment were healed. Figure
7 - Patency after 37 months of follow-up (note that the curve starts in 98.7%
due to the case of acute thrombosis in the immediate postoperative) 
In
primary procedures, 203 nitinol self-expandable stents (Zilver, COOK) were used,
mean of 2.6 stents per SFA (ranging between one and seven stents). Estimated length
of recanalizations ranged between 3 and 43 cm, mean of 16 cm in SFA recanalization.
The analysis of stent measures demonstrated the tendency of using long stents,
still prevalent in our most recent patients. As to diameters, the data reflect
the preference, in the first months using this technique, for 10-mm stents in
the segment above Hunter's canal and 8-mm stents in the SFA below Hunter's canal
and popliteal artery. This has not been observed in our recent patients, since
we have preferred 8-mm stents in the SFA segment above Hunter's canal associated
with 6-mm stents below this canal. Among
the complications inherent to the surgical technique, there were three femoral
ruptures (2.3%), which were treated with temporary balloon inflation using the
angioplasty balloon; three patients (2.3%) presented groin hematoma, with good
clinical evolution after conservative therapy, and 12 patients (9.3%) presented
elevation in serum creatinine levels greater than 1.9mg/dl; however, there was
no need of hemodialysis in any of these patients, who returned to preoperative
creatinine levels after about 30 days. As to the stents used, there was one case
of macroscopic fracture of a stent unit, visualized in the control high-definition
radiography, performed every 6 months. This fracture did not generate loss of
recanalization patency.
DISCUSSION
It seems obvious to believe that the same results
obtained in the coronary territory could be applied to the other arterial beds,
such as SFA. However, when the different studies on these territories are compared,
there is great disparity in the literature.15-20 It
is believed that this occurs because the SFA is longer, has a larger caliber and
is subject to more pressure, flexibility and mechanic changes in many directions.8
Other complications, such as stent fracture, seem to be more frequent in this
segment.5 This
controversy, however, is one step ahead in the discussion on its applicability
and benefits, well defined in studies such as SIROCCO I and II, which are important
studies assessing the use of nitinol stents in the femoropopliteal territory.5,8
To date, we only have data from a large consensus, TASC, recommending femoropopliteal
angioplasty as the first choice in classes A and B, and relative choice in classes
C and D.21 Nevertheless, this consensus is already
delayed due to the fast evolution in techniques and materials over the past years.
A TASC review has been increasingly recommended by many, including ourselves,
especially with regard to indications of SFA angioplasty. In
the lesions described in this study, the technique was always the same, independent
of TASC classification. The only influence of this classification concerned recanalized
distances, which were longer and used a greater number of stents in patients included
in categories C and D. Many studies
show promising success rates in SFA angioplasty, such as that by Karch et al.,
with around 40% of patients asymptomatic for 4 years and possibility of endovascular
reintervention in about 50% of primary failure cases.22
Age, final quality of angioplasty (for example, residual stenosis, presence of
dissection) as predictors of immediate success; the main factor influencing recurrent
stenosis and occlusion in the long term (more than 12 months) in this study was
the final quality of angioplasty.22-26 TASC
compared 11 studies dealing with stent angioplasty in the femoropopliteal segment,
in a total of 585 patients, and mean primary patency was 67% (ranging between
22 and 81%) in 23 months and 58% in 36 months. On the other hand, in the studies
referring only to angioplasty, without using stents (eight studies, 1,241 patients),
patency rates were 61% in 12 months and 51% in 36 months.22
It should be stressed that, in these studies, both the technique and the materials
were not exactly the same reported here. A
major differential in the main multi-centered studies on the use of stents in
SFA was confirming that, in this territory, the mechanic factor is significantly
overlapped, to the extent of judging that the disagreeing results as to recurrent
degree of stenosis, occlusion, clinical deterioration and fractures are directly
related to the material and design of stents, as well as to their physical characteristics,
markedly their radial force and flexibility.8 Schlager
et al.27 evaluated the rates of recurrent stenosis,
clinical deterioration and fractures among Wallstents (Boston Scientific) and
two types of nitinol self-expandable stents, SMART (Cordis) and Dynalink/Absolute
(Guidant). Both for immediate recurrent stenosis and for clinical deterioration,
the data were favorable to nitinol stents without differences between both types;
as to fracture rate, the difference between the two types of nitinol stents was
significant: whereas the fracture rate of SMART (Cordis) was 28%, the Dynalink/Absolute
(Guidant) presented a 2% rate. Results like these suggest that, in the current
stage of technological development, the individual results of each stent model
should be evaluated before using the stents available in the market. By
comparing the results obtained in this series with other similar series in the
literature, we tried to identify the clinical impressions that we associated with
the patency rates obtained and stressed some relevant issues of the technique
used in this study. The main difference
is undoubtedly in the tendency to perform long recanalizations and always cover
the angioplasty territory with self-expandable nitinol stents. We believe that,
by selectively using stents in cases of residual stenosis after angioplasty, only
the recoil effect, which is more immediate, is avoided, and not the remodeling,
which occurs late. Stents, when systematically used, will promote the contention
of these two main factors on angioplasty failure, out of the four factors mentioned
earlier. Homolateral femoral puncture,
for several reasons, as in obese patients, is impaired and may progress with obstructive
complications exactly in the origin of the artery to be treated, so we always
chose the contralateral puncture. A homolateral puncture avoids the resolution
of high lesions and increases the risk of plaque detachment and SFA embolism,
besides demanding compression or use of percutaneous closing devices, which are
not free from complications and have a potential to reduce distal blood flow,
damaging arterial recanalization. In our experience, we did not have complications
due to the use of contralateral puncture. Similarly,
the experience in the conventional surgical treatment of femoral arteries shows
us that atherosclerotic plaques usually considered "localized" to arteriography
are actually much more extensive, and the "localization" is nothing
more than an area of greater stenosis concentration. We believe the stent recanalization
in a long segment avoids the occurrence of fractures in plaques located near this
greater stenotic concentration, which will already be a focus of greater inflammatory
reaction after angioplasty. It is known
that stent edges present the highest occurrence of recurrent stenosis after stent
angioplasty. For that reason also, in cases that present two or more "localized"
lesions, we cover the whole territory between the stents, according to the technique
described in this study. The stent
used in this series (Zilver, COOK) has specific characteristics of design and
resistance compared to other models, which we believe are responsible for part
of the favorable results. This stent markedly has increased radial force, maybe
because it is a stent also used in the treatment of biliary lesions, which can
assure greater recoil and arterial remodeling control. In addition, the stent
design has smaller spaces in its frame, which could prevent intimal hyperplasia,
but at the same time allow blood flow through it, maintaining the patency of arterial
branches originated from recanalized segments, as observed in many control examinations
(Figure 3). Platelet aggregation and
selective use of anticoagulation in some patients are other important measures
to maintain patency and, above all, the frequent follow-up of patients with clinical
and complementary examinations every 6 months promotes early identification of
recurrent stenoses, providing better results in a second recanalization, and especially
preventing the occurrence of occlusions. Our
experience using the technique of SFA recanalization has proved to be satisfactory,
with long-term patency rates similar or better than those obtained with femoropopliteal
bypasses before using the endovascular technique, without the undesired common
complications of conventional surgery. Surely
there is still skepticism around the technique of SFA recanalization, and the
use of stents in this segment is probably a controversial theme. However, in a
wide analysis of device evolution, we noted a strong tendency in favor of both.
In our daily experience, this already became the first choice about 5 years ago,
generating significant benefits to our patients. CONCLUSIONS
As observed by Palmaz in a recent review,28
the fast evolution in this area over the past years is remarkable, with greater
perspective for the following years in terms of nanotechnology, microelectronics
and material technology, all of these significantly involved in the engineering
of new generations of intravascular devices. Following the technological evolutions,
we believe that it is also necessary to adapt ourselves to the surgical techniques,
which is exactly what we tried to describe here. We
consider the SFA recanalization technique a less invasive method, with few complications
and considerable anatomic success and patency rates, which are able of promoting
satisfaction and quality of life to patients with POAD.
REFERENCES
1.
Sousa JE, Costa MA, Abizaid AC, et al. Sustained suppression of neointimal proliferation
by sirolimus-eluting stents: one-year angiographic and intravascular ultrasound
follow-up. Circulation. 2001;104:2007-11. 2.
Sousa JE, Costa MA, Abizaid A, et al. Lack of neointimal proliferation after implantation
of sirolimus-coated stents in human coronary arteries: a quantitative coronary
angiography and three-dimensional intravascular ultrasound study. Circulation.
2001;103:192-5. 3.
Marx SO, Jayaraman T, Go LO, Marks AR. Rapamycin-FKBP inhibits cell cycle regulators
of proliferation in vascular smooth muscle cells. Circ Res. 1995;76:412-7. 4.
Poon M, Marx SO, Gallo R, Badimon JJ, Taubman MB, Marks AR. Rapamycin inhibits
vascular smooth muscle cell migration. J Clin Invest. 1996;98:2277-83. 5.
Duda SH, Pusich B, Richter G, et al. Sirolimus-eluting stents for the treatment
of obstructive superficial femoral artery disease: six-month results. Circulation.
2002;106:1505-9. 6.
Henry M, Klonaris C, Amor M, Henry I, Tzvetanov K. State of the art: which stent
for which lesion in peripheral interventions? Tex Heart Inst J. 2000;27:119-26. 7.
Hoffmann R, Mintz GS, Dussaillant RG, et al. Patterns and mechanisms of in stent
restenosis: a serial intravascular ultrasound study. Circulation. 1996;94:1247-54. 8.
Davies MG, Waldman DL, Pearson TA. Comprehensive endovascular therapy for femoropopliteal
arterial atherosclerotic occlusive disease. J Am Coll Surg. 2005;201:275-96. 9.
Oliva VL, Soulez G. Sirolimus-eluting stents versus the superficial femoral artery:
second round. J Vasc Interv Radiol. 2005;16:313-5. 10.
Lee C, Tan H, Lim Y. Update on drug-eluting stents for prevention of restenosis.
Asian Cardiovasc Thorac Ann. 2006;14:75-82. 11.
Duda SH, Poerner TC, Wiesinger B, et al. Drug-eluting stents: potential applications
for peripheral arterial occlusive disease. J Vasc Interv Radiol. 2003;14:291-301. 12.
Heldman AW, Cheng L, Jenkins GM, et al. Paclitaxel stent coating inhibits neointimal
hyperplasia at 4 weeks in a porcine model of coronary restenosis. Circulation.
2001;103:2289-95. 13.
Scheinert D, Scheinert S, Sax J, et al. Prevalence and clinical impact of stent
fractures after femoropopliteal stenting. J Am Coll Cardiol. 2005;45:312-5. 14.
Sacks D, Marinelli DL, Martin LG, et al. Reporting standards for clinical evaluation
of new peripheral arterial revascularization devices. J Vasc Interv Radiol. 2003;14:S395-404. 15.
Hong MK, Kornowski R, Bramwell O, Ragheb AO, Leon MB. Paclitaxel-coated Gianturco-Roubin
II (GR II) stents reduce neointimal hyperplasia in a porcine coronary in-stent
restenosis model. Coron Artery Dis. 2001;12:513-5. 16.
Zdanowski Z, Albrechtsson U, Lundin A, et al. Percutaneous transluminal angioplasty
with or without stenting for femoropopliteal occlusions? A randomized controlled
study. Int Angiol. 1999;18:251-5. 17.
Vroegindeweij D, Vos LD , Tielbeek AV, Buth J, vd Bosch HC. Balloon angioplasty
combined with primary stenting versus balloon angioplasty alone in femoropopliteal
obstructions: A comparative randomized study. Cardiovasc Intervent Radiol. 1997;20:420-5. 18.
Chatelard P, Guibourt C. Long-term results with a Palmaz stent in the femoropopliteal
arteries. J Cardiovasc Surg (Torino). 1996;37(3 Suppl 1):67-72. 19.
Sapoval MR, Long AL, Raynaud AC, Beyssen BM, Fiessinger JN, Gaux JC. Femoropopliteal
stent placement: long-term results. Radiology. 1992;184:833-9. 20.
Liermann D, Strecker EP, Peters J. The Strecker stent: indications and results
in iliac and femoropopliteal arteries. Cardiovasc Intervent Radiol. 1992;15:298-305. 21.
Strecker EP, Boos IB, Gottmann D. Femoropopliteal artery stent placement evaluation
of long-term success. Radiology. 1997; 205:375-83. 22.
TASC working Group. -Management of peripheral arterial disease (PAD) TransAtlantic
Inter-Society Consensus (TASC). Eur J Vasc Endovasc Surg. 2000;19 Suppl A:1-244. 23.
Karch LA, Mattos MA, Henretta JP, McLafferty RB, Ramsey DE, Hodgson KJ. Clinical
failure after percutaneous transluminal angioplasty of the superficial femoral
and popliteal arteries. J Vasc Surg. 2000;31:880-7. 24.
Vroegindeweij D, Tielbeek AV, Buth J, van Kints MJ, Landman GH, Mali WP. Recanalization
of femoropopliteal occlusive lesions: a comparison of long-term clinical, color
duplex US, and arteriographic follow-up. J Vasc Interv Radiol. 1995;6:331-7. 25.
Surowiec SM, Davies MG, Eberly SW, et al. Percutaneous angioplasty and stenting
of the superficial femoral artery. J Vasc Surg. 2005;41:269-78. 26.
el-Bayar H, Roberts A, Hye R, Davis G, Freischlag J. Determinants of failure in
superficial femoral artery angioplasty. Angiology. 1992;43:877-85. 27.
Schlager O, Dick P, Sabeti S, et al. Long-segment SFA stenting-the dark sides:
in-stent restenosis, clinical deterioration, and stent fractures. J Endovasc Ther.
2005;12:676-84. 28.
Palmaz JC. Intravascular stents in the last and the next 10 years. J Endovasc
Ther. 2004;11 Suppl 2:II200-6. |
