Primary stenting versus balloon angioplasty in treating superficial femoral artery lesions

Primary stenting versus balloon angioplasty in treating superficial femoral artery lesions

Wagih Fawzy,MD; Ayman A Hassan,MD; Ahmed Abou Elnaga,MD

Department of Vascular Surgery, Ain Shams University, Cairo, Egypt.

Abstract

Background: The superficial femoral artery (SFA) is the site of> 50% of atherosclerotic

plaques that develop in the human vascular tree. These lesions were previously amenable only to surgical bypass, but now the endovascular therapy altered this line of treatment. However, still there is a debate in using primary stents to treat such lesions.

Aim of the study: To compare primary stenting versus simple balloon angioplasty in treating

SFA TASC II type A orB lesions.

Patients and methods: 40 patients presented by chronic lower limb ischemia were divided randomely into 2 groups. Each involved 20 patients. Group I was treated by primary stenting and group II by simple balloon angioplasty. The lesions treated belonged to TASC II (type A or B) lesions. Follow up at 6 months and one year was done as regards the patency and development of restenosis.

Results: The mean lesion length treated was 10.1 em ±3 em.30% of the lesions were complete occlusions. The patency in both groups was 100% along the whole period of the study.10% of group I and 25% of group II developed restenosis at 6 months. At the end of the first year, a total   of  20%   of  group  I  and   56.2%  group  II     developed  restenosis  >50%.

Conclusion: Primary stenting of SFA lesions (TASC II type A or B) is recommended as it improves the one year outcome as regards development of restenosis.

Keywords: Angioplasty, stenting, SFA.

Introduction:

Atherosclerosis is the most common cause of symptomatic arterial occlusion in human vascular tree: one of its most common sites is the femoropopliteal segment where more than

50% of atherosclerotic plaque lesions occur. The lesions may be focal, discrete or may involve the entire 30 em length of the vessel. Stenoses, occlusions or both may be present, although occlusions are three times more common than stenoses.1

The superficial femoral artery (SFA) is one

of the longest arteries in the body. It has two major flexion points, the hip and the knee. The presence of few collateral vessels, many forces exerted on the SFA include torsion, compression, extention and  flexion  exert significant stress on the SFA.2

Endovascular therapy  has dramatically altered the treatment of peripheral arterial disease (PAD). Lesions previously thought

amenable only to open surgical bypass can now be successfully managed percutaneously.3

Atherosclerotic lesions  with complex morphology such as calcified lesions, eccentric stenoses and plaques with ulceration or focal aneurysm, are prone to develop complications, when treated by balloon angioplasty alone, as elastic recoil, dissection and/or significant residual stenosis (which occur in up to 30% of cases). This results in unsatisfactory long term patency rates. Accordingly, primary stenting (stent placement without prior balloon angioplasty) is more effective in treating such lesions.4

For more than a decade, femoropopliteal stent implantation remained a bailout procedure after complicated balloon angioplasty. But the introduction of self-expanding nitinol stents once again, changed the treatment strategy of femoropopliteal disease.5

Self-expanding nitinol stents have improved radial strength with shape-memory characteristics that promots crush recoverability. They  also  have  reduced foreshortening which allows precise placement. These properties led to better patency rates compared to earlier stent designs encouraging the use of primary stenting of SFA lesions.6

Aim of the study:

The aim of the study was to compare primary  stenting versus simple balloon angioplasty in treating SFA lesions as regards the patency and restenosis over one year of trea1ment

Patients and methods: Study design:

A randomized controlled study was conducted in Ain Shams University hospitals involving 40 patients  comparing primary stenting to simple balloon angioplasty for the SFA  atherosclerotic occlusive diseases.

The patients were divided into 2 equal groups, each included 20 patients that were randomely treated as follows:

Group1:In whom primary stenting of the

SFA was done.

Group II: In  whom  simple balloon

angioplasty was performed.

All patients enrolled in the study had the following inclusion criteria.

1- The presentation was critical limb ischemia (CLI) or very short distance claudication interfering with their life style. CLI was

defined by  the  European consensus document as the presence of ischemic rest pain requiring opiate analgesia for at least

2 weeks, ankle systolic presSltt'e lower than

50mmHg and/or toe systolic pressure lower

than 30 mmHg or presence of ulceration

or gangrene.

2- The lesion was type A or B according to classification of trans-atlantic inter-soceity consensus  (TASC)  IF femoropopliteal lesions, as shown inTable(l).

3- All lesions involved were atherosclerotic.

4- All patients had normal renal functions.

Table (1): Clllssification of trans-atlantic intN-soceity consensus (TASC) HfemoropoplituJ

lesions.

Type A loslons

o                        steoo5is  10cmtnlengtu

• sn,..nc:ck.lslon 5 em In ·

Type B lesions

o M.alplleSions (stcnoseo 01     lo eac:t1  5 em

0 Slncje 0116 em ncii-MIIvif1g tho

Wm gcriculiJte popliteal """'Y

o Sfr9e "'1JU14>1e lesions tn absence d coodnuaos

dblai \'OS5els 10 irnp'o.e .....lcf II c)isWI bypass

o Heuvliy ulcllecl ocduslon  5 an In1eng111

o SirpoplleelstenO>is

Type Clcolons

o MUitfple .,_or cx:c r.; ons totaling>15 em

wid1..-10ithou1 he8vy Cll4cillaltion

o Recurent .,enoscs or oc:cklslcns d10t need

·· - -- endovosculor '"'

TypcOie<loos

o  Clwoclic tacal orouslom ol CFA 0< SFA \>:10 em,

ltM>!Wlg ""' pcplilealartety)

o Chronic: tccal oroll5klnsdpcl!llilealarteryand

p.-Oldmol tmrcatlon \'OS5els

Any  patient not  fulfilling any  of these criteria, was  excluded from the  study.

A preoperative evaluation was done for all

patients involving:

1- Risk factors for atherosclerosis including: smoking, diabetes mellitus, hypertension, dyslipidemia, obesity, coronary artery disease, and  cerebral vascular disease.

2- Kidney  function tests  (S. creatinin , Bl.

Urea) to  exclude preoperative renal impairment.

3- Bleeding profile.

4- Clinical evaluation of the limb including the ankle brachial index (ABI).

5- Multi-slice CT angiography including the

lower abdominal aorta and the lower limb arteries  to   delineate  the    lesions. A loading  anti-platelet therapy namely,

clopidogrel, was given  24 hours  before  the procedure  which was continued  at least one year after the procedure.8

Procedures:

An access to the lesion was obtained through

an antegrade common femoral artery (CFA).9

Retrograde CFA  access was used in obese

patients  or if the lesion was in the proximal third of the SFA.3

A single-wall puncture needle  (16 or 18 gauge) accommodating up to 0.35 inch guide wire was used. Then a 6 French sheath  was introduced to obtain an access port to the artery.

After confirming an intra-arterial access, systemic  anticoagulation was obtained  with

50-100 IU/kg  of  intravenous heparin.

The lesion was crossed using a 0.035 inch hydrophilic guide wire.This may be aided by a 4 or 5 F diagnostic multipurpose catheter that improves the steerability of the wire and provides additional support  for crossing the lesion.

In group I, a self-expandable nitinol stent of 6 mm diameter was used to cover the lesion.

The stent was placed without prior balloon angioplasty.4 Thena 6 mm balloon was inflated inside the stent to obtain an optimum result as detected by  imaging control Figure(l).

In group II, a simple balloon angioplasty using 6 mm balloon  was used to dilate  the lesion controlled by intra-operative imaging Figure(2).

Figure (1): Primary stenting of occluded lower third of right SFA:

A.  Pre-stenting angiogram showing occluded lower   third  of  right  SFA  (arrows)

B. Past-stenting angiogram showing successfUl revascularization (site of the stent marked by

arrows)

-&iiihl!fiii!ffNtiiDfJ4fP'

Figure (2): Simple hal/on angioplasty of7 em.occlusion of left SFA:

A. Pre-stenting  angiogram  showing  occluded  7 em. segment  of  left  SFA (arrows) B. Balloon dilatation of the occluded segment (an-ow showing the waist of the balloon) C.   Past-stenting  angiogram  showing  successful  revascularization  (arrows)

Postoperative follow up:

1- Clopidogrel was given for all patients one year postoperatively.

2- Immediate postoperative clinical response

(technical success) was evaluated using the clinical response of the preoperative presentation and the ABI.

3- Patency of the procedure was assessed at 6 and  12  months   by  arterial  duplex.

4- A multi-slice CT angiography was done if

duplex was inconclusive.

The success of theprocedure was considered when there was freedom from> 500/o restenosis in the target vessel.

Results:

40 patients with SFA lesions were enrolled in the study, that were divided randomely into two equal groups:group (20 patients), treated

by primary stenting and group n(20 patients),

treated   by  simple  balloon  angioplasty.

Of the 40 patients, 30 (75%) were males

and 10 (25%) were females. Their ages ranged from (42-93 years) with a mean age of67.7 years. 32 patients (80%) were diabetics, 27 patients (67.5%) were hypertensive, 30 patients (75%) were smokers, 28 patients (70%) had dyslipidemia, 16 patients (40%) were obese,

25 patients (62.5%)badcoronary artery disease,

and 8 patients  (20%) had cerebral vascular

disease. There was no statistical significant difference between both groups as regarding demographic data  and atherosclerotic risk factors.

32 patients (80%) presented by tissue loss in the form of ischemic ulcers or foot gangrene. The remaining 8 patients (20%) had short distance claudication. The ABI ranged from

0.2-0.5. There was no statistical significant difference between both groups regarding the

clinical presentation of patients.

The   preoperative  multi-slice   CT

angiography revealed a mean lesion length of

10.1±3 em. 70% (28 patients) had diffuse disease (multiple or single stenosis in the affected segment) and 30% (12 patients) bad

complete occlusion. All the lesions were confined to the SFA with good distal ( tibial arteries ) run off. Also, there wasno statistical significant difference between the two groups considering CT  angiography findings.

4 patients (20%) from group II, required

secondary stenting due to suboptimal results of simple balloon angioplasty (in the form of residual stenosis > SO%,recoil or flow limiting dissection). However, these patients were excluded from the study.So, at the end of the study, group IIwere analyzed as 16 patients only.

Revascularization of SFA was associated with good clinical response in all patients of the two groups. After treatment, claudication

Table (1): Results at 6 months after treatment.

and  rest  pain  disappeared, and foot  ulcers and/or minor amputation stumps healed.

P value > 0.05

As shown in Table(2): after 6 months of treatment, patency of the treated arteries was

100% in both groups. 2 patients (10%) from group I and 4 patients  (25%)  from group II developed  restenosis >50%, but this was not statistically significant. However, all of these restenosis were asymptomatic and no further interventions were required.

Table (3): Results at 11months after treatment.

As demonstrated in  Table(3): after  12 months of treatment, patency  of the treated arteries was 100%. 5 patients (20%) in group I and 9 patients (56.2%) in group IT developed restenosis >50%, with aP-value of0.01, which is highly  significant. One patient  in group I

and 3 patients in group nbecame symptomatic

and required re-intervention.

P value> 0.01

Discussion:

Percutaneous transluminal interventional techniques have  profoundly changed the management of vascular occlusive disease. The acceptance of such techniques was gradual and hard fought, and there was significant resistance from the surgical community. Today, there is  a  major shift from   surgery to angioplasty in patients with peripheral arterial occlusive disease.IO

The SFA is one of the most common sites of  PAD where more than 50% of atherosclerotic plaques occur. As these lesions are mostly complex, they are prone to develop complications when treated by simple balloon angioplasty.l.4

The endovascular treatment of SFA lesions remained in a debate, some documented the essential use of primary  stenting although others  documented the  efficacy of simple balloon angioplasty and secondary stenting on

demand as a line of choice in the management of such lesions.ll·12

This randomized controlled study involved

40 patients aiming to compare primary stenting versus simple balloon angioplasty in treating SFA lesions as regards patency and restenosis over one year postoperatively.

Diabetes  mellitus,   smoking,  and

dyslipidemia account for the most common risk  factors for  atherosclerosis in our community. They were present in 80%,75%, and   70%,   respectively in  our   patients.

20%  of  our  patients treated by  simple balloon angioplasty (group II) developed intra­ operative complications that required secondary stenting. This  was  less than those in ABSOLUTE trial,13 balloon angioplasty versus stenting with nitinol stents in the SFA, in which

32% required secondary stenting, but, it was

more  than  those  in FAST  (femoral artery stenting trial),14 in which only 11% required

secondary stenting. This difference might be due to the short length of lesion treated in FAST (mean 4.5 em) , while in our study and in ASBOLUTE trial it was more than 10 em. The cause of use of secondary  stenting  was mainly  flow limiting dissection or residual stenosis > 30%.

The 6 months follow up of our patients revealed no difference inpatency inboth groups (100% in both) and no significant difference inrestenosis (I0% and 25% respectively). This was similar to the results in ABSOLUTE trial which was 23.5% and 43.4% respectively)3

However, at the end of the frrst year, there was high significant difference inthe incidence of> 50% restenosis, it was 20% ingroup I and

56.2% in group II. These results were similar to many trials, as in ABSOLUTE triaJ13 which was 36.7% and 63.5% and  RESILIENT (randomized study  comparing the Edwards self-expanding life stent versus  angioplasty alone)  trial ,15 which detected  restenosis  in

20% and 62%, respectively.

Also,  similar results were  obtained in ASTRON trial16 (balloon angioplasty versus primary stenting  of femoropopliteal arteries using self-expandable nitinol stents)  which were  34.4% and   61.1%,  respectively.

In the DURABILITY triaJ17 of the stented

SFA lesions done, only  8.7%  developed restenosis at 6 months and 27.7% at one year follow up.

However,in FAST trial,14 it was found that

there was insignificant difference inboth groups as regards the development of restenosis which was 32% and 39% , respectively denoting no benefit in using stent in SFA lesions with respect to restenosis prevention.

Table(4) summarizes the results of different trials compared to our study in using primary stenting (Group I)  versus  simple balloon angioplasty (Group  II) in treatment of SFA lesions.

Table (4): Results of different trials compared to our study.

Group I (primary  stenting) & Group II (simple balloon angioplasty)

So, most of the trials and our study, support the use of primary  stenting  in SFA  lesions (TASC  II type  A or B lesions), which  had superior results than simple balloon angioplasty as  regards  development of  restenosis.

Conclusion:

Primary stenting of the SFA  lesions described in TASC II (type A or B lesions) is recommended as an endovascular approach to treat these lesions because it improves the one year  outcome as  regards development of restenosis.

References:

1- Hertzer NR, Cambria RP, Stone DH, et al: The natural history of peripheral vascular disease. Implications for its management. Circulation 2004;  83:  112-119.

2- Cheng CP, Wilson NM, Hallett RL, et al: In vivo MR angiographic quantification of axial and twisting deformations of the SFA resulting from  maximum hip  and  knee flexion. J Vase Interv Radio/ 2006;  17:

979-987.

3-  Ayerdi J, Hodgson KJ:  Fundamental techniques in  endovascular surgery.