Cath Lab Digest

   Given the challenges of managing chronic wounds in patients with peripheral arterial disease, these authors offer a review of current concepts in revascularization and how these procedures may facilitate improved wound healing.

   Perfusion is the most fundamental requirement to heal a wound. According to current estimates, peripheral arterial disease (PAD) affects over 12 million people in the United States and more than half are asymptomatic.^1,2

   As PAD progresses to advanced stages such as non-healing wounds or critical limb ischemia (CLI), the risk of lower limb amputation increases. For these patients, it is paramount to ensure a strong vascular supply to the lower extremity if one is to accomplish the goal of wound healing.³

   Multidisciplinary care is critical for these high-risk patients. Accordingly, it is incumbent upon podiatrists to be aware of emerging advances in revascularization in order to make appropriate referrals, when necessary, to vascular specialists.

A Pertinent Primer On Bypass Techniques

   Over the years, physicians have employed multiple techniques to overcome and treat vascular diseases of the lower extremity. Lower extremity bypass, angioplasty and stenting are just a few of the treatments vascular surgeons have utilized for the revascularization of a compromised limb.³ Autogenous grafts remain the gold standard for vascular conduits.

   The graft material is one of the most important factors in influencing long-term patency.^2-6 The five-year patency rates for autogenous vein grafts reportedly range between 60 and 80 percent. The five-year patency rates of polytetrafluoroethylene (PTFE), the most common prosthetic material, are significantly less.

   Graft failure within 30 days is most commonly correlated with inadequate outflow, poor quality conduit or improper procedure selection. Progression of underlying atherosclerotic disease is the main contribution to graft failure after two years. Between these times, intimal hyperplasia is the predominant cause of graft failure. Intimal hyperplasia most commonly occurs at the distal anastomosis with higher failure rates occurring with longer grafts of small diameter.^2-6 Intimal hyperplasia is responsible for 60 percent of graft failures following peripheral arterial reconstruction. Likewise, it is the predominant lesion when it comes to mid- to long-term failure of angioplasty and stenting.^2-6

   The molecular basis for restenosis is not clearly defined but may share similar pathways as those identified for artherogenesis. These pathways include abnormalities of lipid metabolism and involvement of inflammatory cells. Evolving vascular strategies based on gene therapy techniques have been developed to prevent restenosis but there have not been sufficient results.

   When one performs an open procedure appropriately, it can follow an endovascular procedure that has failed. Similarly, an endovascular procedure can often follow an open procedure in the setting of a failing graft.⁴

What About Advances With Percutaneous Transluminal Angioplasty?

   Percutaneous transluminal angioplasty (PTA) with or without adjunctive stenting of iliac, femoral and popliteal and tibial lesions attempts to restore adequate perfusion to the lower extremity. The PTA involves a controlled injury to plaque in the arterial wall, which creates a localized dissection of the adventitial and medial layers with balloon angioplasty.