3.1 / IAGS 2019
Session 3: Endovascular Session 1
Is “Leave Nothing Behind” the Right Approach to the SFA?
Problem Presenter: James P. Zidar, MD, FACC, FSCAI
Statement of problem and gaps in our knowledge
Current endovascular strategies for superficial femoral artery (SFA) and popliteal intervention started with “plain old balloon angioplasty” or PTA, often with long balloons. This approach is quick and cheap, but may not provide the optimum outcome, especially with very long lesions, calcified vessels, chronic occlusions (CTOs), or dissected vessels. Atherectomy provides an alternative to PTA at a higher cost, but may optimize vessel wall preparation for drug-coated balloons. We have the options of rotational and directional atherectomy (CSI, Rotoblator, Jetstream and TurboHawk) and also laser atherectomy. Although longer-term outcome data are quite sparse for these treatments, this strategy extends the lesion types one can approach from an endovascular perspective. Embolic protection is frequently required. Impressive early experience with Shockwave “lithoplasty” has been accumulating for calcified SFA vessels, and without the need for distal protection.
Self-expanding nitinol stents have been available for years and are ideal in the short term to treat severe dissections, but long stents do poorly in the longer term, with high restenosis rates and frequent re-occlusions. Even the Supera woven stent, which can sustain the forces of popliteal flexion, has long-term restenosis issues. Drug-coated nitinol stents (Zilver PTX) are more expensive and have shown modest long-term benefits over PTA, but restenosis within these and other stents is much harder to treat. The first drug-eluting peripheral stent on the US market (Eluvia) outperformed the Zilver PTX in the randomized Imperial trial at 1 year of follow-up.
Drug-eluting balloons (DCBs) with paclitaxel (In.Pact Admiral, Lutonix, Stellarex, and Ranger balloons) are currently the most popular strategy, after several small randomized trials suggested benefit vs PTA at 1 and 2 years of follow-up. However, dissections are often left behind and the cost of this technology is high. In the United States, DCBs are often used after lesion preparation with atherectomy or lithoplasty in calcified lesions. Heparin-coated stent grafts (Viabahn) have been used to treat very long SFA disease or sub-intimal recanalization of CTOs. Restenosis tends to limit itself to the edges of the graft. However, the cost is high and the failure mode is more dramatic, as the collateral circulation has been sacrificed.
Possible solutions & future directions
At the current time, most US peripheral interventionalists use an aggressive lesion preparation strategy followed by DCB for most SFA lesions, in an effort to “leave nothing behind.” However, it is much more difficult to avoid stents for severe adventitial dissections, or CTOs that were recanalized into the subintimal space. Most operators are much more likely to “spot stent” than a decade ago. Unfortunately, a recent meta-analysis from Greece (Katsanos, JAHA, published Dec 2018) suggested late mortality concerns with paclitaxel DCBs. This paper has thrown the clinical world into current confusion as we await further patient level outcomes data. Until these data are presented, the field remains in a state of uncertainty.