We spoke to Dr. Jose Joaquin Muñoz Ruiz-Canela to learn more about his presentation at CIRSE 2022.
SFA – covered stents
Treatment of superficial femoral artery (SFA) occlusive disease remains one of the most challenging procedures for the peripheral vascular interventionalist. Unlike interventions, especially stenting of other vessels such as coronary, renal or iliac arteries, long-term patency following a SFA intervention has been difficult to achieve. Avoidance of femoral-popliteal bypass surgery using venous conduit is reasonable because many of these patients have concurrent coronary artery disease and the saphenous vein may be needed later for coronary artery bypass surgery . Many patients are simply managed medically; some, though relatively few, do achieve significant relief from symptoms with an exercise programme .
A large number of devices have been developed and studied for the treatment of SFA disease, likely due to the generally inadequate long-term results of balloon angioplasty for all but the simplest and shortest lesions .
Compared to femoropopliteal bypass, the interventional data remain limited, with only a handful of studies examining patency rates for more than one or at most three years, while surgical follow-up data often extends to ten years. This limitation is in part due to the “moving target” nature of intervention compared to surgery. While femoropopliteal bypass has been a stable procedure for decades, interventional devices constantly evolve, so that by the time a study with one- or two-year follow-up is completed, the device is often outdated either because a new and improved iteration has replaced the original device, or because an entirely new device has come into development. Complicating the issue further is that many trials include lesions that are simpler and shorter than the “real world” disease doctors face daily. For example, many trials exclude long lesions, chronic total occlusions, severely calcified stenoses, vessels with poor distal run-off and ostial SFA disease .
In many practices, these features are more the rule than the exception. The morphologic features that occur in the distal SFA and proximal popliteal artery, make it easy to understand why satisfactory long-term interventional results have been difficult to achieve, even with a host of different approaches. The length of the SFA and the extreme flexion, not to mention shortening/extension, torsion and compression also make long-term studies difficult . Lesions in SFA are complex in morphology and it is a unique vessel characteristic.
Although many devices have targeted various morphologic challenges (e.g. calcification, elastic recoil, dissection, thrombus), none has addressed the challenge of long lesion length. In general, the restenosis rate is linearly related to the length of the vessel treated for nearly every device available. Although most clinical trials report an average lesion length of <10 cm, patients with severe diffuse disease and/or chronic total occlusion often have lesion lengths >25 cm and sometimes longer .
- Plain balloon angioplasty (POBA)
- Bare metal stents (BMS), nitinol stents
- Paclitaxel based therapy
- Drug coated balloons (DCB)
- Drug coated stents (DES)
- Self-expandable covered stents
- Others: atherectomy (AT), etc.
Rationale to use covered stents 
- To reduce the incidence of restenosis
- To reduce the in-stent restenosis (ISR) to edge restenosis which is easier to treat and the incidence is independent of lesion length
- Clinical data is encouraging
Viabahn Endoprosthesis 
- It is an endoluminal bypass with potential edge restenosis
- In contrast with other stents, Viabahn has an length independent restenosis rate
- Some studies compare covered stent grafts versus others treatments on femoropopliteal lesions
Femoro-popliteal by pass versus Viabahn 
- Identical results for the two procedures
- Lesion length in Viabahn group 25.6 cm
- Similar results at one, two, three and four years
- Utilised the older version of Viabahn without heparin bonding and the contouring proximal edge
VIPER study 
- Gore VIPER clinical study data primary patency as a function of proximal oversizing
- Is a single arm study with 119 patients, with long SFA lesions (mean length 19 cm), chronic total occlusion 56% and moderate to severe calcifications in 61% of the patients
- One year primary patency was 74%, secondary one year patency was 92% with Doppler ultrasound (DUS)
- One year primary patency was 88% oversizing <20% and 70% when oversizing <20%
- Sizing is critical: primary patency is significantly better when IFU sizing is not exceeded at the proximal edge
VIASTAR study [5,6]
- Is a physician initiated, prospective, randomized multicenter trial
- It compares Viabahn (V) versus bare metal stents (BMS) in complex lesions
- The average lesion lengths were 19 cm (V) vs 17 cm (BMS)
- CTO procedures were 78% versus 70%, respectively
- One year primary patency were 78% versus 54% p=0.009, respectively
- One year primary patency of lesions>20 cm 73% versus 33% p=0.004, respectively
- It was significantly higher primary patency results using covered compared to BMS. This improvement is even greater in long, complex lesions
RELINE study 
- Is a prospective randomised trial comparing Viabahn versus PTA
- There were 39 versus 44 patients, respectively
- The mean of lesion length was 17 versus 19 cm and the incidence of CTO´s 23% vs 25%, respectively
- One year primary patency was superior in the Viabahn group (74.8%) versus PTA group (28%)
Japan IDE trial 
- Is a single arm, prospective study with 103 patients
- The mean of the lesions was 23 cm and CTO was 66%
- Used learning from VIPER for recommendations
- At 24 months primary patency was 92%, secondary patency 87,2% and freedom from TLR 78.8% and 79.1% at five years
VANQUISH trial 
- Physician initiated, prospective, multicenter study
- Enrolled 424 limbs in 371 patients treated with a Viabahn stent-graft placement in femoropopliteal artery
- The purpose of this study was one year patency outcomes in real world setting and evaluating the role of hypercoagulability
- A full-coverage stent-graft was selected in 343 limbs (81.1%), whereas the remaining 80 limbs (18.9%) underwent spot implantation
- The one year primary patency in full coverage group was 80.3% and in the spot group 68% (p=0.025)
- A smaller vessel size was significantly associated with loss of patency
- The prothrombotic state was not associated with loss of patency
VIABAHN in chronic limb threatening ischaemia 
- Most studies focus in intermittent claudication (IC)
- There are some studies focusing in Viabahn in chronic limb ischemia (CLI) patients
- Technical success was 93%
- Most patients were treated with one or two endografts with 6 mm the most common diameter
- The hospital stay was three days (IQR two to seven days) and 30-day mortality was 2%
- Survival at two years was 78% and 62% were free from other reinterventions
- The two-year patency rates were primary 60%, assisted primary 63%) and secondary 86%
- The two-year freedom from minor amputation was 95% and major amputation 99%
SFA covered stent possible indications
- Complex long lesions from 10-25 cm
- Complications of PTA (arterial rupture, dissection) in long lesions
- Long chronic total occlusions
- Complex lesions from 3-10 cm
Key technique points 
- Stent “normal to normal” vessel
- Do not worry about covering collaterals in SFA
- If stenting back to the proximal SFA, it is best to stent back to the SFA origin
- Use ipsilateral angulated view to align the Viabahn with the SFA origin
- Do not cover vessels < 4.5 mm in diameter
- Do not oversize Viabahn more than 20% of true diameter
- Dual antiplatelet therapy for a minimum of six months and preferably indefinitely if not clinically contraindication
- Posdilate with PTA but do not allow the balloon to extend pass the edge of the Viabahn stent to avoid edge dissection and restenosis
- Perform DUS every four months for one year then every six months, treat if peak systolic velocity > 300 cm/sec
- Consider telescoping from 5 mm Viabahn distally to larger 6 mm. Viabahn proximally, always overlap Viabahn stents by 1-2 cm
- SFA complex lesions are a challenge to treatment
- Covered stent are an endoluminal by pass
- A high percentage of long lesions and CTOs
- Studies have demonstrated a better performance compared with BMS and similar technical outcomes compared to FP bypass surgery with faster recovery
- Possibility of edge restenosis and thrombosis
- VIABAHN: smaller profile, contouring proximal edge and heparin bonding
- We have to choose an adequate size device
- Monitoring one year with DUS
- In case of thrombosis use thrombolysis
- BMS stenosis could be treated with covered stent (RELINE STUDY)
- Self-expanding covered stents can also be safely used in patients with CLI
Jose Joaquin Muñoz Ruiz-Canela
Regional University Hospital of Malaga, Malaga/ES
Dr. JJ Muñoz is the coordinator of the department of vascular and interventional radiology at the Regional University Hospital of Malaga in Malaga, Spain. He has published numerous book chapters and journal articles for national and international publications; he is also the author of the book: Learning Vascular and Interventional Radiology. In addition, he has participated in many national and interventional congresses with papers, posters and speaking lectures. He was the president of SERVEI from 2007-2009 and is a member of SIDI and CIRSE.
- Weinstock BS. Covered stents in the treatment of superficial femoral artery disease. VMD 2014;11 (4):E76-E86
- SFA Endoluminal Bypass: Optimizing clinical outcomes using the Gore Viabahn Endoprosthesis for the treatment of TASC C and D lesions in the SFA. Endovascular Today (supplement), February 2007.
- McQuade K et al. Four-year randomized prospective comparison of percutaneous ePTFE /nitinol selfexpanding stent graft versus prosthetic femoro-popliteal by pass in the treatment of superficial femoral artery occlusive disease. JVS 2010;52(3);584-591.
- Saxon RR, Chervu A, Jones PA, et al. Heparin-bonded, expanded polytetrafluoroethylene-lined stent graft in the treatment of femoropopliteal artery disease: 1-year results of the VIPER (Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease) trial. J Vasc Interv Radiol. 2013;24(2):165-173.
- Lammer J, Zeller T, Hauseger KA, et al. Heparin-bonded covered stents versus bare metal stents for complex femoro-popliteal artery lesions: the randomized VIASTAR trial. J Am Coll Cardiol. 2013;62(15):1320-1327.
- Geraghty PJ, Mewissen MW, Jaff MR, Ansel GM; for the VIBRANT Investigators. Three-year results of the VIBRANT trial of VIABAHN endoprosthesis versus bare nitinol stent implantation for complex superficial femoral artery occlusive disease. J Vasc Surg. 2013;58(2):386-395.
- Bosiers M. RELINE study: Randomized comparison of endoluminal grafting with Viabahn vs. PTA for femoral artery in-stent restenosis—6 months results. Paper presented at: Leipzig Interventional Course; January 28-31, 2014; Leipzig, Germany.
- Michael MPH Reijnen. Personal presentation. LINC 2022
- Aboyans V et al . European Heart Journal (2018) 39; 763-821. 2017 ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, in collaboration with the European Society for Vascular Surgery.