Infrapopliteal Bypass

Updated: Apr 11, 2017
  • Author: Cheong Jun Lee, MD; Chief Editor: Vincent Lopez Rowe, MD  more...
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Overview

Background

Infrapopliteal bypass is a major lower-extremity arterial reconstruction, the goal of which is to establish in-line flow to target vessels such as the tibial, peroneal, or pedal arteries. Arterial supply (inflow) sites therefore include the common femoral, deep femoral (profunda femoris), superficial femoral, and popliteal arteries. Occasionally, a tibial artery may become the inflow vessel.

The primary indication for infrapopliteal bypass is critical limb ischemia (CLI) due to atherosclerotic peripheral arterial disease (PAD). This method of surgical arterial reconstruction can be applied to patients with nonatherosclerotic conditions such as aneurysmal disease and traumatic arterial injuries. The bypass conduit should usually be composed of autogenous vein, but prosthetic material can be used in the absence of suitable autogenous conduit. [1]

With regard to conduit type, vein grafts are superior to all prosthetic conduits for infrapopliteal bypass, regardless of target vessel. [2, 3]  The great saphenous vein (GSV; also referred to as the long or greater saphenous vein) is the most commonly utilized autogenous conduit; however, the small saphenous vein (SSV; also referred to as the short or lesser saphenous vein), the superficial femoral vein, [4]  and spliced vein grafts from the arm can also be used. [5]

Numerous varieties of prosthetic conduits are available; options include the following:

  • Dacron
  • Heparin-bonded Dacron
  • Human umbilical vein
  • Polytetrafluoroethylene (PTFE)
  • Heparin-bonded PTFE

Of these, PTFE is the most commonly used material. All prosthetic grafts perform with similar patency rates in the infrapopliteal position and are inferior to autogenous grafts, regardless of type; composite grafts appear to be no better than prosthetic grafts in this regard. [3]  The 1-year patency rates of vein conduit in the infrapopliteal position reach 70-80%, whereas those of prosthetic grafts reach 30-50% at best. [2]  If a prosthetic graft is used in the infrapopliteal position, an adjunctive vein cuff at the distal anastomosis improves patency. [6]

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Indications

Indications for infrapopliteal bypass include the following:

  • Symptomatic lower-extremity ischemia (eg, disabling claudication, rest pain, or tissue loss)
  • Aneurysmal disease
  • Traumatic arterial injury
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Contraindications

Contraindications for infrapopliteal bypass include the following:

  • Debilitated patient with severe comorbidities
  • Lack of an appropriate distal target for revascularization
  • Unaddressed inflow disease
  • Severe joint contractures
  • Nonambulatory patient
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Technical Considerations

Best practices

The principles of surgical revascularization are based on the following three components:

  • Inflow
  • Outflow
  • Conduit

The inflow vessel (ie, the artery from which the bypass will originate) must have adequate flow and pressure and allow suturing. Significant vascular calcification or atherosclerotic disease of the inflow artery can present technical challenges. The outflow vessel should be the least diseased vessel with runoff to the foot. On imaging, inflow and outflow arteries must be well characterized. If disease exists in the proposed inflow vessel and a less diseased more proximal artery cannot be accessed or used because of bypass graft length constraints, an adjunctive procedure to address the inflow disease (eg, endarterectomy) must be added to the operative plan.

The distal target artery must be confirmed to be the dominant vessel to the foot. Tissue distribution of the outflow vessels must correlate with the operative indication. For example, whereas revascularization of the pedal arteries will aid in healing of ischemic foot ulcers, it will not improve calf claudication. In general, shorter reconstructions, if feasible, have better long-term patency. [2, 7]

With regard to conduit assessment, duplex vein mapping is vital for ensuring a graft of appropriate size and quality. The venous conduit should be at least 2.5 mm in diameter and soft throughout the length needed to perform the bypass. Calcified or sclerotic veins should not be used.

Complication prevention

Measures to help prevent complications include the following:

  • Thorough preoperative assessment of the inflow and target vessels
  • Thorough assessment of the vein conduit
  • Strict attention to sterile technique in the handling of prosthetic grafts
  • Systemic heparinization of patients before vessel clamping and after graft tunelling
  • Assessment of the reconstruction at the time of the operation with duplex ultrasonography or intraoperative arteriography
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