Preprocedural Planning
Patients requiring arterial reconstruction of the lower extremities frequently have significant medical comorbidities, with a particularly high prevalence of coronary artery disease (CAD).
A thorough and expeditious perioperative assessment and optimization of underlying CAD and medical comorbidities should precede intervention. First, it is essential to confirm ischemia-related claudication and critical limb ischemia (CLI), which is defined as rest pain and tissue loss. Functional and ambulatory status should be carefully assessed; patients with limited function of the affected limb should not undergo major extremity revascularization.
Assessment of lower-extremity arterial insufficiency should begin with the ankle-brachial index (ABI) and be followed by detailed anatomic characterization of the inflow and outflow arteries. [15]
The criterion standard imaging modality for defining the vascular anatomy before revascularization is arteriography. Substantial advances have been made in computed tomography (CT) angiography (CTA) and magnetic resonance angiography (MRA), and these modalities may provide sufficient detail for operative planning. In patients with relative contraindications for these imaging modalities, duplex arterial mapping may provide the anatomic information needed to proceed without formal arteriography.
Equipment
Equipment employed for infrapopliteal bypass incldues the following:
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Standard vascular clamps and instruments
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Tunneling device (eg, Gore tunneler; W. L. Gore and Associates, Flagstaff, AZ)
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Polytetrafluoroethylene (PTFE) or other prosthetic grafts of appropriate length and caliber (for infrainguinal and infrapopliteal reconstruction, 6-mm grafts are commonly used)
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Doppler ultrasonography (US) device to assess blood flow intraoperatively
Patient Preparation
Anesthesia
The operation is most often performed with general anesthesia because exposure of the groin, exploration and harvesting of vein conduits, and tunneling of the graft proximal from the groin to the distal target site can be difficult to tolerate. In cases where underlying cardiopulmonary disease precludes general anesthesia, however, the procedure can be performed with spinal or regional anesthesia and sedation.
Positioning
The procedure is performed with the patient supine. The patient is prepared in a sterile fashion from the umbilicus down to the lower extremities. The extremities are prepared circumferentially. If an upper-extremity vein is required, the arms are extended and prepared.
Monitoring & Follow-up
Establishment of graft surveillance protocols is essential to maintaining the long-term patency of lower-extremity bypass grafts. Lesions that threaten graft patency can be readily identified and monitored for progression with serial ABI determination and graft duplex US.
The authors' center uses scheduled examination at 1 month postoperatively, then at 3 months, at 6 months, and yearly thereafter. Grafts with focal lesions associated with a peak systolic velocity higher than 300 cm/s, a velocity ratio greater than 3.5, or a change in ABI greater than 0.15 undergo further imaging with arteriography or MRA to identify potential inflow, outflow, or other graft lesions, which are addressed expeditiously.
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Infrapopliteal bypass from popliteal artery to dorsalis pedis artery. Procedure performed by Roman Nowygrod, MD, ColumbiaDoctors, New York, NY. Video courtesy of ColumbiaDoctors (http://www.columbiadoctors.org).
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Infrapopliteal bypass. Distal superficial femoral artery and above-knee popliteal artery exposure.
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Infrapopliteal bypass. Below-knee popliteal artery exposure.
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Infrapopliteal bypass. Posterior tibial artery exposure.
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Infrapopliteal bypass. End-to-side running anastomosis.
