Catheter-based therapy of the femoro-popliteal tree is the most frequently performed peripheral intervention and is an accepted first-line therapy in selected patients with intermittent claudication in whom exercise treatment combined with pharmacological therapy has failed. While the degree of a patient's disability is a prime consideration, the anticipated short- and long-term clinical benefits are the major determinants of the role of catheter techniques in patients with femoro-popliteal disease. Balloon angioplasty and metallic stent implantation are major technical advances that have improved acute procedural results and increased the use of endovascular procedures in patients with more extensive, complex disease. However, the long-term efficacy of endovascular procedures in complex lesion types has not been fully defined.

• Indication
- Intermittent claudication
- Critical limb ischemia (rest pain, ulceration, gangrene, poor wound healing)
- Improve inflow or outflow, before or after vascular bypass surgery
- Bypass graft stenosis or anastomotic lesion
- Impending amputation (to improve the level)

• Relative contraindication
- Ulcerated plaque with atheroemboli
- Long total occlusion (iliac > 4cm, superficial femoral artery > 10cm), unless converted to shorter occlusion by thrombolysis
- Heavy, eccentric calcification
- Lesion in or adjacent to essential collaterals

• Absolute contraindication
- Mild or moderate stenosis with no significant pressure gradient
- Stenosis immediately adjacent to an aneurysm
- Embolic occlusion

American Heart Association and TransAtlanttic Inter-Society Consensus (TASC II) document provides evidence-based recommendations for treatment to intermittent claudication patients. In TASC II, femoro-politeal lesions are classified into 4 categories: type A-D. TASC classification of femoral popliteal lesions.

• TASC A and D lesions: Endovascular therapy is the treatment of choice for type A lesions and surgery is the treatment of choice for type D lesions.
• TASC B and C lesions: Endovascular treatment is the preferred treatment for type B lesions and surgery is the preferred treatment for good-risk patients with type C lesions. The patient's co-morbidities, fully informed patient preference and the local operator's long-term success rates must be considered when making treatment recommendations for type B and type C lesions.

- ACC/AHA guideline summary : endovascular treatment for claudication

Class I - There is evidence and/or general agreement that endovascular treatment is beneficial in the following settings
• A patient with claudication that causes significant disability that limits lifestyle and/or work is not adequately responsive to exercise or pharmacologic therapy, has a reasonable likelihood of improvement, and is due to a lesion with a favorable risk-benefit ratio (eg, focal aortoiliac occlusive disease). Before intervention for 50 to 75 percent angiographic iliac artery stenoses, translesional pressure gradients should be obtained, with and without vasodilation, to determine the significance of the lesion.
• A patient with claudication that causes significant disability that limits lifestyle and/or work is not adequately responsive to exercise or pharmacologic therapy, has a reasonable likelihood of improvement, and is due to a lesion with a favorable risk-benefit ratio (eg, focal aortoiliac occlusive disease). Before intervention for 50 to 75 percent angiographic iliac artery stenoses, translesional pressure gradients should be obtained, with and without vasodilation, to determine the significance of the lesion.
• TASC type A (single stenosis less than 3 cm) iliac and femoropopliteal arterial lesions for which endovascular treatment is the preferred revascularization technique.
• Provisional stent placement in iliac arteries as salvage therapy for a suboptimal or failed result from balloon angioplasty alone (as manifested by a persistent translesional gradient, residual diameter stenosis of more than 50 percent, or a flow-limiting dissection).
• Stenting as primary therapy for stenoses and occlusions of the common or external iliac artery.

Class IIa - The evidence or opinion is in favor of endovascular treatment being beneficial in the following setting
• Stents (and other adjunctive percutaneous techniques such as atherectomy and cutting balloons) in the femoral, popliteal, and tibial arteries as salvage therapy for a suboptimal or failed result from balloon angioplasty alone as defined above.

Class IIb - The evidence or opinion is less well established that endovascular treatment is beneficial in the following settings
• Stents and other adjunctive percutaneous techniques for femoropopliteal arterial lesions, except as salvage therapy for a suboptimal result from balloon angioplasty
• Uncoated/uncovered stents and other adjunctive percutaneous techniques infrapopliteal lesions, except as salvage therapy for a suboptimal result from balloon angioplasty

Class III - There is evidence and/or general agreement that endovascular treatment should not be performed in the following settings
• Absence of a significant pressure gradient across a stenosis despite flow augmentation with vasodilators.
• Primary stent placement (ie, not for salvage therapy) in the femoral, popliteal, or tibial arteries.
• As prophylactic therapy in asymptomatic patients.

The technical and clinical success rate of PTA of femoropopliteal artery stenoses in all series exceeds 95% (range 98%–100%, standard error 1.0%).1 Device developments such as hydrophilic guide wires and technical developments, such as subintimal recanalization, provide high recanalization rates in total occlusions of more than 85% (range 81%–94%, standard error 2.9%).2 The technique of subintimal angioplasty is not as dependent on length, but rather on the presence of normal vessel above and below the occlusion to allow access.3

Stents have been designed to improve the technical success rate and overall arterial patency after peripheral transluminal angioplasty (PTA). By fixing arterial plaque against the arterial tree, stents prevent immediately recoil and obstructive plaque dissection. However, there is a tendency for loss of initial patency due to restenosis (which usually occurs in the first six months) or to progressive atherosclerosis at the lesion site or elsewhere in the same vessel. The smaller vessel diameter is probably the major explanation for the higher rate of restenosis compared to iliac disease.

Previous small randomized trials failed to demonstrate the superiority of PTA plus stent over PTA alone in the femoro-popliteal tree. The largest randomized trial.4 comparing PTA alone versus PTA plus stent (Palmaz, stainless steel stent) in the superficial femoral artery in 227 patients showed that stent use was required in 15% of the PTA-alone group; and 1-year angiographic restenosis was not statistically different between PTA alone and PTA plus stent (32.3% vs. 34.7%, p=0.85). Survival was not different between the PTA alone group and PTA plus stent at 4 years. Therefore, the use of stents was not supported by previous data. Stents may have a role in salvaging acute PTA failure or complications.5-8

Recently, patency at one year improved significantly with development of nitinol stents (ex. Smart stent, Dynalink stent, Expander stent). The several studies using Smart stent achieved one-year patency in 83%-88% of cases. The use of nitinol stents has reported 3-year patency rates of up to 76%.9,10 In nonrandomized one study comparing nitinol and stainless stent implantation for femoro-popliteal artery showed that cumulative patency rates at 6, 12, 24 months were 85%, 75%, and 69%, respectively, after nitinol stent implantation verus 78%, 54%, 34%, respectively after stainless steel stent implantation (p=0.008).11 this results suggested that primary placement of nitinol stents might be more effective than conventional balloon angioplasty.

Recently, in a meta-analysis of randomized controlled trials, currently available data suggest no significant difference in the rate of TVR between PTA with provisional stenting and routine stenting for symptomatic patients with short SFPA lesions, although there is a trend for lower restenosis and a significant higher immediate technical success rate in favour of routine stenting as well as a non-significant trend towards lower TVR with the newer generation nitinol stents.12

*Pooled results of femoral popoliteal dilatation

Risk factors for recurrence were analyzed by multivariate stepwise backward regression analyses in various studies. Clinical stage of disease (intermittent claudication versus critical limb ischemia), length of lesion and outflow disease were most commonly found as independent risk factors for restenoses. Recently, a study by Schillnger of 172 patients successfully undergoing PTA of the superficial femoral and popliteal arteries observed that 6-month patency rates were related to hs-CRP levels at baseline and at 48 hours after intervention.13 Anatomic factors that adversely affect long-term patency include long or eccentric calcified lesions, occlusion instead of stenosis, and poor distal run-off..14,15
Patients undergoing coronary angioplasty or stenting are likely to experience an adverse outcome if they have clinical or angiographic characteristics including diabetes, long calcific lesion, long stent implantation, restenotic lesion, chronic total occlusion, or bifurcation lesion. In the field of peripheral intervention, especially in femoro-popliteal tree, the predictors such as symptoms (claudication vs. critical ischemia), type of lesion (stenosis vs. occlusion), length of lesion, and outflow are associated with adverse outcomes.16,17 Therefore, from the prognostic point of view, the correct choice of PTA or surgery based on published guidelines or the individual patient's condition is necessary to improve patient outcomes.

The pathogenesis of restenosis after PTA is the same as that after coronary artery angioplasty, which smooth muscle cell proliferation and migration being the major events. A number of therapies have been tried in an attempt to prevent restenosis after femoral PTA.

1. Local delivery of paclitaxel – The THUNDER trial randomly assigned 154 patients to paclitaxel coated angioplasty balloons, uncoated balloons with paclitaxel dissolved in the contrast medium, or uncoated balloons with contrast solution containing no paclitaxel. The primary end point of mean late lumen loss after six months was significantly lower in the coated balloon group than either the paclitaxel solution or control groups (0.4 versus 2.2 and 1.7 mm, respectively). The coated balloon group also had a significantly lower rate of target lesion revascularization at six months (4 versus 29 and 37 percent).18 The findings in THUNDER were confirmed in the similarly designed FemPac trial, in which 87 patients undergoing angioplasty of femoropopliteal lesions were randomly assigned to either uncoated or paclitaxel-coated balloons catheters. The primary end point of late lumen loss at six month follow-up angiography was significantly less in the coated balloon group (0.5 versus 1.0 mm).19

2. Stenting - The composition of the stent may influence the rate of stent patency after femoropopliteal intervention and three studies have evaluated the safety and efficacy of self expanding nitinol stents compared to either PTA or steel stents. In an observation study with subsequent randomized trial showed significant reduction of restenosis in self expanding nitinol stents compared to either PTA or steel stents.20.21 But recent the FAST trial of 244 patients with a single, short (mean lesion length of 45 mm compared to 130 mm in the preceding trial) superficial femoral artery lesion and chronic limb ischemia found no advantage compared with PTA. At one year, there was no significant difference in the primary end point of binary restenosis as determined by intravascular ultrasound (32 versus 38 percent, respectively) or the secondary end points of target lesion revascularization and Rutherford category of PAD.22

3. Drug eluting stent – In SIROCCO trial, patients with chronic limb ischemia and TASC type C lesions treated with sirolimus-eluting versus bare SMART nitinol self-expandable stent, the sirolimus-eluting and the bare SMART stent are effective, safe, and free from restenosis in a majority of patients for up to 24 months. Because the restenosis rate in the bare stent group is unexpectedly low, no significant difference could be found between the sirolimus-eluting and the bare SMART stents.23

1.G. Muradin, J. Bosch, T. Stijnen and M. Hunink, Balloon dilation and stent implantation for treatment of femoropopliteal arterial disease: meta-analysis, Radiology 221 (1) (2001), pp. 137?145
2.N. London, R. Srinivasan, A. Naylor, T. Hartshorne, D. Ratliff and P. Bell et al., Subintimal angioplasty of femoropopliteal artery occlusions: the long-term results, Eur J Vasc Surg 8 (2) (1994), pp. 148?155.
3.M. Cejna, S. Thurnher, H. Illiasch, W. Horvath, P. Waldenberger and K. Hornik et al., PTA versus Palmaz stent placement in femoropopliteal artery obstructions: a multicenter prospective randomized study, J Vasc Interv Radiol 12 (1) (2001), pp. 23?31.
4. Becquemin JP, Favre JP, Marzelle BJ et al. Systematic versus selective stent placement after superficial femoral artery balloon angioplasty: A multicenter prospective randomized study. J Vasc Surg 2003;37:487-94
5. Vroegindeweij D, Vos LD, Tielbeek AV, et al. Balloon angioplasty combined with primary stenting versus balloon angioplasty alone in femoropopliteal obstructions: a comparative randomized study. Cardiovasc Intervent Radiol 1997; 20:420?425.
6. 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?255.
7. Cejna M, Turnher S, Illiasch H, et al. PTA versus Palmaz stent in femoropopliteal artery obstructions: a multicenter prospective randomized study. J Vasc Interv Radiol 2001; 12:23?31.
8. Grimm J, Muller-Hulsbeck S, Jahnke T, et al. Randomized study to compare PTA with Palmaz stent placement for femoropopliteal lesions. J Vasc Interv Radiol 2001; 12:935?942.
9. Duda SH, Pusich B, Richter G, et al. Sirolimus-eluting stents for the treatment of obstructive superficial femoral artery disease: 6-month results. Circulation 2002;106:1505?1509.
10. Lugmayr HF, Holzer H, Kastner M, et al. Treatment of complex atherosclerotic lesions with nitinol stents in the superficial femoral and popliteal arteries: a midterm follow-up. Radiology 2002; 222:37?43.
11. Sabeti S, Schillinger M, Amighi J et al. Primary patency of femoropopliteal arteries treated with nitinol versus stainless steel self expanding stents: propensity score-adjusted analysis. Radiology 2004;232:516-521.
12. Kasapis C, Henke PK, Chetcuti SJ, Koenig GC, Rectenwald JE, Krishnamurthy VN, Grossman PM, Gurm HS. Eur Heart J. 2009 Jan;30(1):44-55. Epub 2008 Nov 21.
13. M. Schillinger, M. Exner, W. Mlekusch, H. Rumpold, R. Ahmadi and S. Sabeti et al., Vascular inflammation and percutaneous transluminal angioplasty of the femoropopliteal artery: association with restenosis, Radiology 225 (1) (2002), pp. 21?26.
14. Matsi, PJ, Manninen, HI, Vanninen, RL, et al. Femoropopliteal angioplasty in patients with claudication: Primary and secondary patency in 140 limbs with 1-3 year follow-up. Radiology 1994; 191:727.
15. Capek, P, McLean, GK, Berkowitz, HD. Femoropopliteal angioplasty. Factors influencing long-term success. Circulation 1991; 83:I70.
16. Visona A, Perissinotto C, Lusiani L et al. Percutaneous excimer laser angioplasty of the lower limb vessels: results of a prospective 24-month follow-up. Angiology 1998;49:91-98.
17. Von Polnitz A, Nerlich A, Berger H et al. Percutaneous peripheral atherectomy : angiographic and clinical follow-up of 60 patients. J Am Coll Cardiol 1990;15:182-688.
18. Tepe, G, Zeller, T, Albrecht, T, et al. Local delivery of paclitaxel to inhibit restenosis during angioplasty of the leg. N Engl J Med 2008; 358:689.
19. Werk, M, Langner, S, Reinkensmeier, B, et al. Inhibition of restenosis in femoropopliteal arteries: paclitaxel-coated versus uncoated balloon: femoral paclitaxel randomized pilot trial. Circulation 2008; 118:1358.
20. Sabeti, S, Schillinger, M, Amighi, J, et al. Primary patency of femoropopliteal arteries treated with nitinol versus stainless steel self-expanding stents: propensity score-adjusted analysis. Radiology 2004; 232:516.
21. Schillinger, M, Sabeti, S, Loewe, C, et al. Balloon angioplasty versus implantation of nitinol stents in the superficial femoral artery. N Engl J Med 2006; 354:1879.
22. Krankenberg, H, Schluter, M, Steinkamp, HJ, et al. Nitinol stent implantation versus percutaneous transluminal angioplasty in superficial femoral artery lesions up to 10 cm in length: the femoral artery stenting trial (FAST). Circulation 2007; 116:285.
23.Duda SH, Bosiers M, Lammer J, Scheinert D, Zeller T, Oliva V, Tielbeek A, Anderson J, Wiesinger B, Tepe G, Lansky A, Jaff MR, Mudde C, Tielemans H, Beregi JP.J Endovasc Ther. 2006 Dec;13(6):701-10.
24. Norqren L, Hiatt WR, Dormandy JA et al. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). Eur J Vasc Endovasc Surg. 2007;33 Suppl 1:S1-75.
25. Hirsch, AT, Haskal, ZJ, Hertzer, NR, et al. ACC/AHA 2005 Practice Guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease): endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation. Circulation 2006; 113:e463.