How do you select a site of anastomosis in Peripheral Vascular Disease (PVD)?

Selection of Anastomosis Site in Peripheral Vascular Disease

For lower extremity bypass in PVD, select the most distal artery with continuous uncompromised flow from above and without stenosis >20% as the origin point, and anastomose to the most distal tibial or pedal artery capable of providing continuous outflow to the foot. 1

Principles of Anastomosis Site Selection

Proximal (Inflow) Anastomosis Site

• Use the most distal viable artery as the inflow source to preserve more proximal vessels for future revascularization procedures 1
• The proximal anastomosis should originate from an artery with continuous flow from above and stenosis ≤20% to ensure adequate hemodynamic inflow 1
• For aortoiliac disease requiring aortobifemoral bypass, end-to-end proximal aortic anastomosis yields significantly better patency (87% cumulative patency) compared to end-to-side anastomosis (75% cumulative patency), regardless of distal run-off 2

Distal (Outflow) Anastomosis Site

• Anastomose to the tibial or pedal artery that provides continuous and uncompromised outflow to the foot, even if this requires a longer bypass 1
• The distal target vessel must have adequate outflow without significant stenosis to ensure graft patency 1
• For above-knee popliteal artery bypasses, construct with autogenous saphenous vein when possible 1
• For below-knee popliteal artery bypasses, autogenous vein is strongly preferred 1

Anatomic Hierarchy for Bypass Planning

Upper Extremity (for dialysis access, not typical PVD)

• Follow a distal-to-proximal sequence: wrist radiocephalic fistula → forearm cephalic fistula → antecubital fistula → transposed basilic fistula 1
• This preserves maximum future access sites 1

Lower Extremity Arterial Bypass

• Femoral-popliteal bypass: Anastomose to above-knee popliteal when adequate outflow exists 1
• Femoral-tibial bypass: Use autogenous vein and select the tibial vessel with best continuous flow to the foot 1
• Pedal bypass: Reserved for patients with tibial occlusive disease but patent pedal vessels 1

Preoperative Assessment Requirements

• Duplex ultrasound is useful to select surgical bypass candidates and determine anastomosis sites (Class IIa recommendation) 1
• MRA of extremities may be considered to select patients for surgical bypass and identify optimal anastomosis sites 1
• Contrast angiography provides the most detailed anatomic information and should image iliac, femoral, and tibial bifurcations in profile without vessel overlap 1
• Complete anatomic assessment must include imaging of the occlusive lesion, arterial inflow, and outflow before deciding on intervention 1

Critical Technical Considerations

Arterial Inflow Assessment

• Preoperative evaluation must document anatomic and functional status of arterial vasculature, including brachial artery flow 1
• In diabetic patients, arterial calcification is more pronounced distally (wrist vs elbow), so consider more proximal anastomosis sites in this population 1
• Inadequate arterial inflow may require interventional angioplasty or a more proximally located anastomosis 1

Venous Outflow Considerations

• Hemodynamically significant stenosis is defined as >50% diameter reduction on angiography/ultrasound, supported by clinical symptoms and flow measurements 1
• Juxta-anastomotic venous stenosis commonly occurs from hemodynamic flow changes and venous wall devascularization during surgery 1

Common Pitfalls to Avoid

• Do not bypass distal sites prematurely by starting with proximal anastomoses, as this exhausts future revascularization options 1
• Avoid subclavian vein access for dialysis catheters unless no other option exists, as this can jeopardize future permanent access 1
• Do not place anastomoses in areas with >20% stenosis, as this compromises graft patency 1
• Surgical expertise significantly impacts outcomes—early fistula failure rates are 3-fold higher with occasional surgeons versus experienced surgeons 1

Special Circumstances

When Standard Revascularization Fails

• Venous arterialization (Class IIb recommendation) may be considered for chronic limb-threatening ischemia when no viable arterial revascularization options exist, with 75% limb salvage at 12 months 3
• This involves connecting a proximal artery to a distal vein with valve disruption to allow retrograde arterial flow through venous circulation 3

Axillofemoral Bypass

• Reserved for patients with extensive aortoiliac disease who are not candidates for aortobifemoral bypass 1
• Significantly inferior patency (50-76% at 5 years for axillobifemoral) compared to aortobifemoral bypass (87.5% at 5 years) 1