Standardization of Care for Complex Peripheral Arterial Disease

May 22, 2016

Craig Walker, MD

In the June issue of Vascular Disease Management, Nicolas W. Shammas, MD, proposes an algorithm for treating complex infrainguinal peripheral arterial disease (PAD) with interventional therapy. In his article, Dr. Shammas outlines his suggestions for therapy and his philosophy about what constitutes most effective therapy. 

This article highlights the lack of standardization that is present in today’s treatment of PAD. Unlike coronary disease, where there are high-quality level 1 data to guide therapy once lesions have been crossed, there is no clear evidence-based algorithm to guide peripheral arterial therapies. Treatment at present is by individual preference guided by bits and pieces of scientific information. Because of this, therapies vary widely among practitioners. This practice may result in increased overall costs and suboptimal outcomes. 

There are many reasons that therapies are not yet standardized. Whereas stents have typically resulted in higher patency than standard balloon angioplasty in the superficial femoral arteries, patency is not as good as it is in other vascular beds. Stenting is associated with fractures and problematic in-stent restenosis. We have no randomized trials comparing newer best-in-class stents to drug-eluting stents and covered stents. While atherectomy removes plaque and doesn’t require leaving a foreign body in place, other than 308 nanometer excimer laser utilized for treating in-stent restenosis, there are no randomized controlled data with atherectomy in PAD. There is a large observational study (DEFINITIVE LE) utilizing directional atherectomy that is encouraging, but it does not reach level 1 data. Other atherectomy trials in de novo lesions are not large and are not randomized. Paclitaxel drug-eluting balloon treatments have shown a statistically significant improvement in patency in the superficial femoral artery and popliteal vessels out to 1 year, and longer in several studies, but many patients were excluded from the studies. The excellent patency rates in the control arms are not yet explained. Paclitaxel treatment of infrapopliteal lesions has had conflicting results. Combination therapies utilizing atherectomy followed by drug-eluting balloons seem to be reasonable, but we lack randomized controlled data at this point. The trials that we have predominantly compare newer devices to standard percutaneous transluminal angioplasty rather than each other.

Without randomized controlled trials to guide therapies, it is difficult to achieve appropriate standardization. Unfortunately, the trials that are needed are prohibitively expensive, and appropriate randomization is difficult. The rapid pace of innovation in peripheral intervention has the potential to make conclusions obsolete because newer treatments with potentially better outcomes may not be included. Perhaps a reasonable alternative would be a large-scale registry that would include initial and long-term outcomes, initial and long-term costs, complications, and morbidity. Lesion lengths, lesion characteristics, disease states, symptomatic presentation, medical therapy, and comorbid conditions would need proper documentation.

We are far from having the type of data that will be required to make informed decisions about the proper therapy in each case. In the interim, decisions must be guided by limited scientific information, personal skillset, and experience.