Neoaortoiliac System Procedure for Treatment of an Aortic Graft Infection

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

• 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.

• 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.

• 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.

Pitfalls and Danger Points

• Hemorrhage from conduit

• Acute limb ischemia

• Compartment syndrome

• Deep vein thrombosis and venous hypertension

Operative Strategy