Historical Background
Dissatisfaction with traditional single-stage or multistage extraanatomic bypass followed by resection of infected aortic grafts arises from aortic stump blowout after excision of the infected graft and more importantly from compromised long-term performance of axillofemoral reconstructions. Ehrenfeld and colleagues reported their experience with in situ reconstruction of the aorta using endarterectomized arterial autografts in 1979. Limitations with available arterial conduit prevented widespread adoption of this technique. Early reports of in situ reconstruction after excision of infected aortic grafts using saphenous vein described a conduit plagued by diffuse intimal hyperplasia. In 1981 Schulman and Badhey used femoral popliteal vein (FPV) as an alternative conduit for infrainguinal revascularization. Separate reports published in 1993 described the use of FPV as an autogenous graft for aortic reconstruction, and the term neoaortoiliac system (NAIS) was used to describe the reconstructed vessels using FPV. The large caliber of the FPV lends itself to direct anastomosis with the aorta, and concerns of late aneurysmal degeneration or graft blowout were not realized. Long-term follow-up suggests that clinically significant venous complications are infrequent. Excellent patency, limb salvage rate, and lack of recurrent infection make the NAIS procedure an often preferred method of treatment.
Preoperative Preparation
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The initial care of the patient with an aortic graft infection should be directed toward treatment of systemic or local sepsis. If possible, culture-directed systemic antibiotic therapy should be initiated. Hemodynamic instability related to sepsis may require aggressive intravenous hydration or resuscitation, invasive monitoring, and vasoactive medication. Extensive preoperative evaluation of cardiac risk is often unnecessary given the life-threatening nature of aortic graft infection and the need for expeditious surgical therapy.
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Duplex ultrasound, computed tomography angiography, magnetic resonance imaging, conventional arteriography, nuclear imaging, and positron emission tomography scanning aid in defining the extent of graft infection and arterial-graft anastomotic integrity. In instances of subacute biofilm infection, imaging studies may be inadequate and operative graft exploration may be necessary to confirm an infectious etiology as a cause for an anastomotic pseudoaneurysm. Preoperative imaging also provides information regarding the original procedure and arterial anatomy. The location and configuration of the aortic anastomosis and anastomotic pseudoaneurysms, and the presence of prior lower extremity arterial reconstructions can be accurately assessed. This knowledge is of great value if infrainguinal revascularization for ischemia is required after aortic reconstruction. Finally, radiographic studies define associated abscess or involvement of surrounding viscera.
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Both lower extremities should be evaluated with venous duplex imaging. The lower extremity veins should be evaluated for (1) patency and caliber of the FPV, (2) absence of deep vein thrombosis, (3) presence of duplicated FPVs, and (4) presence or absence of the great saphenous veins.
Operative Strategy
Selection of Conduit for in Situ Repair
Preoperative imaging of the FPV is used to confirm the absence of deep vein thromboses, assess conduit size, and identify duplication of the deep venous system. In the latter situation removal of the larger-caliber FPV and preservation of its duplicate may reduce complications related to chronic swelling or venous hypertension after complete harvest. Full reconstruction of an aortobifemoral configuration usually requires complete use of bilateral FPVs. However, reconstructions after partial graft excisions (“hemi-NAIS” procedures) or removal of aortic or aortoiliac grafts may require considerably shorter lengths.
Staging the Neoaortoiliac System Procedure
Clinical stability in a patient may afford some logistic flexibility. Staging FPV harvest as a separate procedure can save the more difficult graft excision and reconstruction for a second operation on a different day without an increase in overall operative time or complication rate. In such patients the veins are mobilized and left in situ, maintaining axial venous continuity and flow. The wounds are temporarily closed, and standard prophylactic antithrombotic therapy is initiated. When ready, the patient returns to the operating room, the veins are removed, and the definitive procedure is completed.
Operative Technique
Harvesting Femoral Popliteal Vein
Full lower extremity circumferential preparation is required, and the limbs are positioned in a frog-leg manner. The incision is made over the sartorius muscle, from the groin to the medial knee ( 
and Fig. 34-1 , A ). The sartorius is reflected medially, allowing exposure of the Hunter canal. This area represents the division between the anterior and the medial adductor compartments of the thigh; its contents include the femoral artery and vein and the saphenous nerve. The overlying aponeurosis is opened, and the vein is the first visible vascular structure. Mobilization of the vein begins with exposure of its anterior surface. Dissection of the femoral vein is carried centrally to its confluence with the deep femoral vein. Branches of the mobilized femoral vein are doubly ligated flush with the main vein rather than at a distance from the vein often described for saphenous vein harvest. This flush ligation pulls in adventitia, adding strength to the ligature, and does not result in significant impingement of the large lumen. If the full length of FPV is needed, exposure and dissection of the popliteal vein requires division of the adductor longus insertion at the adductor hiatus ( Fig. 34-1 , B ). Up to 15 cm of usable popliteal vein may be obtained in continuity with the femoral vein, but care should be taken to preserve major popliteal venous branches and at least one popliteal valve in the residual stump, thus preserving venous collaterals after graft excision and preventing excessive venous hypertension.
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