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Most single-vessel, mildly symptomatic, or asymptomatic blockages of vessels below the knee aren't appropriate for endovascular intervention, according to new guidance from the Society of Cardiac Angiography and Interventions.

Critical limb ischemia with pain, skin breakdown, or both are the predominant clinical indications for such treatment of infrapopliteal arterial disease, , of the University of South Carolina in Greenville, and colleagues wrote in the consensus recommendations from the organization.

But treatment of moderate-to-severe claudication or major tissue loss in one-vessel disease, as well as mild claudication, even in two- or three-vessel disease, would rarely be appropriate, according to the document released .

Non-ambulatory patients with a short life expectancy and extensive necrosis or gangrene also wouldn't be candidates and should get primary amputation instead, it said.

Ambulatory patients with a patent infrapopliteal artery feeding direct flow to the foot and adequate autologous venous conduit should be considered for surgical bypass if its risk is acceptable.

"Patients with significant medical co-morbidities that limit life expectancy, those at increased risk for surgery, those without an adequate distal target for bypass, or with poor venous conduit should be considered for an endovascular-first approach," Gray and colleagues added.

Asymptomatic patients shouldn't get either interventional or surgical procedures to improve infrapopliteal blood flow, added co-author , chair of the Massachusetts General Hospital Institute for Heart, Vascular, and Stroke Care in Boston.

"I think that's an important statement from this document," he told 乌鸦传媒. "There's a temptation in patients who claim they're having a hard time walking due to leg discomfort and the predominance of their disease is below the knee to try to improve blood flow.

"The problem is the techniques we have available now have limited durability and so the patient will be dissatisfied if within the first year there's a significant amount of restenosis and they're symptomatically back to where they were," Jaff said.

"Also, there are risks involved. You could actually turn a patient with mild intermittent claudication into one with limb-threatening ischemia by having an adverse event from a procedure."

Balloon angioplasty is the current standard for endovascular therapy for clinically significant below-the-knee arterial disease, according to the guidelines.

Bailout bare-metal and drug-eluting stents in the tibial arteries should be considered when that procedure fails, it said.

Combined strategies, like atherectomy and drug-coated balloons, are being studied, but more data is needed on those and other alternative strategies for clearing infrapopliteal arteries.

"Until these results are available, given the increased costs of other modalities (e.g., cutting balloons, cryoplasty, laser, orbital, rotational, and directional atherectomy catheters), and the lack of comparative data to support their efficacy, balloon angioplasty should remain the initial endovascular therapy for most infrapopliteal disease," the guidelines stated.

Situations considered appropriate for treatment of below-the-knee arteries were:

• Moderate-to-severe claudication (50% or more stenosis) with two- or three-vessel infrapopliteal disease, if the arterial target lesion is focal
• Ischemic foot pain during rest -- Rutherford Classification 4, which improves with dependent position, like dangling off the bed -- with two- or three-vessel disease, "to provide direct flow to the plantar arch and to maximize volume flow to foot"
• Minor tissue loss with two- or three-vessel disease, for the same reason as with ischemic rest pain
• Major tissue loss, marked by skin necrosis and gangrene, with two- or three-vessel disease, "to prevent major amputation and to facilitate healing a minor amputation"

Intervention could also be appropriate, depending on individual circumstances, for the following:

• Moderate-to-severe claudication in two- or three-vessel disease with occlusion or diffuse disease
• Ischemic pain during rest with one- or two-vessel disease
• Minor tissue loss with one-vessel disease

Those recommendations assume that inflow disease has already been revascularized and that lifestyle-limiting claudication has been refractory to pharmacologic and exercise therapy, the document noted.

Follow-up after treatment should include noninvasive studies with the goal of normalizing the ankle-brachial index, and improving toe perfusion pressure and transcutaneous oxygen pressure, according to the guidelines.

The recommendations -- the first expert consensus appropriate-use document from a professional society for infrapopliteal arterial disease -- are third in an appropriate-use series from SCAI.

Aorto-iliac and femoral-popliteal arterial intervention guidelines have already been published. A fourth on renal artery procedures is due out in the next couple of months.

The guidelines are timely, Jaff suggested.

"Peripheral arterial disease of the limbs is becoming a more common problem for two reasons mainly. One, it's a disease of an older age population, and the population around the world is getting older. And two, diabetes is a very important risk factor for peripheral arterial disease of the limbs and is becoming pandemic in nature around the world," he said.

"We're going to be seeing more and more patients with this."

UPDATE: This article, originally published July 18, 2014, at 4:14 p.m., was updated with new material July 18, 2014, at 7 p.m.

From the American Heart Association:

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