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Point/Counterpoint: Covered stent grafts vs. drug-eluting stents for treating long superficial femoral artery occlusions


 

References

There is one report used to argue against the use of the Viabahn stent graft (J. Vasc. Surg. 2008;47:967-74). This study evaluated prospectively 109 patients (71 for claudication; 38 for critical limb ischemia) treated for SFA occlusive disease (mean lesion length 15.7 cm). Only 19 of the 109 patients (17%) were treated with Viabahn (17 for claudication; 2 for critical limb ischemia). The remaining limbs were treated with various other BMS devices (n=10). The authors concluded that patients initially treated with Viabahn who presented back with occlusion had a higher chance of presenting with acute symptoms (i.e., a worse Rutherford score). The lesion length treated in the Viabahn group, however, was nearly twice as long as all the other stent platforms combined (25.4 cm vs. 13.7 cm) and there was a higher level of tibial artery deterioration with thrombosis of the BMS group, compared with the Viabahn group (7.7% vs. 5.3%). The number of Viabahn patients presenting with acute thrombosis was not defined. With the small number of limbs treated in the Viabahn group, the conclusions expressed cannot be statistically supported.

What about the in-vogue DES device?

Dr. Dake and his colleagues recently presented 5-year data on the Zilver DES platform at VIVA 2014. He reported a primary patency at 5 years of 66.4% showing superiority to angioplasty alone as well as angioplasty with provisional stenting. This study enrolled 479 patients into the randomization arm and also had a registry arm that although often included in reporting of patency, does not stand up to the scrutiny of peer review. Even though there were some patients with longer lesions, the randomized arm mean lesion length was only 66 mm, which does not compare to the published longer mean lesion length of the Viabahn device. Bosiers et al. (J. Cardiovasc. Surg. 2013 54:115-222) reviewed 135 patients treated with the Zilver device (a subgroup derived from the 787 patients enrolled in the registry data of the Zilver trial) with a mean lesion length of 226 mm. They reported 77.6% primary patency but only at 1 year. Again, however, this is registry derived data and does not have the scientific validity of a randomized trial.

So what can I conclude from these experiences? We know today that covered stent grafts have been widely used and reported on, including by Dr. Dake himself (Radiology 2000 October;217:95-104) and all appear to have had similar conclusions.

The mean lesion length treated in these studies of Viabahn is often longer than 15 cm and nearly all studies report primary patency outcomes. Zilver supporters on the other hand are prone to quote TLR which is an inferior endpoint (as recently noted in an editorial by Dr. Russell Samson (Vasc. Spec. 2015;11:2). Costs of both devices are an issue but may vary by region and institution. However, Viabahn does have the advantage of longer devices, compared with the Zilver (15 and 25 cm vs. 10 cm) so fewer devices may be required to treat long lesions. Although short lesions may be better addressed with BMS or DES, for longer SFA lesions over 12-15 cm there are very few truly comparable data that argue against the use of Viabahn.

Dr. Gable is chief of vascular and endovascular surgery at The Heart Hospital Baylor Plano (Tex.). He is also an associate medical editor for Vascular Specialist. He disclosed that he is a consultant, speaker, and receives research support from W. L. Gore and Medtronic.

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