Historical Background

The development of prosthetic grafts has extended the vascular surgeon’s ability to replace or bypass diseased arterial segments. However, the risk of infection, although small, constantly looms over a patient with an indwelling prosthetic graft, and preventive measures remain the most effective means of infection control. When infection occurs, subsequent degeneration of the anastomosis with arterial bleeding is potentially both limb and life threatening. Few attempts at drainage and sterilization can clear the infection when a foreign material remains in proximity, and infection involving the anastomosis inevitably leads to hemorrhage. The principles of management of an infected prosthetic have two objectives: removal of infected prosthesis and restoration of blood flow to the affected extremity. Although historical teaching mandates complete removal of the infected prosthetic with revascularization using a new conduit placed in an alternative, noninfected route, recent data have suggested that in situ reconstruction with an autogenous conduit or even a prosthetic conduit may provide an alternate treatment option in select patients. In 1963 the obturator bypass was described by Shaw and Baue, which proved to be a durable option for lower extremity revascularization. Although infection complicates the management of femoral pseudoaneurysm, most such lesions are degenerative without associated infection. In prior practice suture breakdown was an important etiology, whereas arterial degeneration is responsible in the modern era.

Indications

• •
  

  All anastomotic femoral aneurysms require treatment, because they are at risk for continued enlargement and rupture. This posture is, or course, tempered in patients with limited longevity.

Preoperative Preparation

• •
  

  The physical findings and time interval from initial operation can direct the extent of evaluation that is required before surgical intervention. Hemorrhage or a draining abscess are emergent conditions that are best managed in the operating room. Chronic infection or degenerative processes allow time for comprehensive evaluation.

  
  
• •
  

  Abscesses or wounds should not be probed at the bedside because of the risk of disruption of a loose clot that could lead to extensive bleeding.

  
  
• •
  

  If infection is suspected, blood cultures should be obtained and empirical antibiotics should be initiated.

  
  
• •
  

  Echocardiography should be considered to exclude valvular vegetations that may alter clinical management, antibiotic choice, and duration of treatment.

  
  
• •
  

  If infection manifests as a chronic process, thorough evaluation of vasculature with ultrasound, as well as conventional, computed tomography (CT) or magnetic resonance angiography, can be performed. Sinus tracts may be identified between the skin or bowel and the graft. Although normal in the postoperative period, perigraft fluid or soft tissue attenuation is suggestive of infection. Ultrasound- or CT-guided drainage of fluid may be diagnostic and suggest direct antibiotic therapy. Although rarely necessary, a tagged leukocyte study can also be obtained.

Pitfalls and Danger Points

• •
  

  Shaw and Baue advised that “a bold and well conceived surgical approach to this problem is much preferred over timid, unjustifiably hopeful procrastination and half measures.” The greatest pitfall with an infectious process is to be conservative, which inevitably leads to limb loss or death.

  
  
• •
  

  All infected graft should ideally be removed, but the physiologic condition of the patient sometimes mandates a less aggressive approach. Close monitoring of any residual prosthesis is mandatory because it remains at risk for infection.

  
  
• •
  

  Preservation of retrograde iliac artery flow may be difficult to achieve at the time of vascular reconstruction. Therefore the status of both hypogastric arteries must be appreciated on preoperative studies to ensure adequate pelvic perfusion.

Operative Technique for a Noninfected Anastomotic Femoral Artery Pseudoaneurysm

Exposure and Vascular Control

The dissection begins with identifying the superior portion of the proximal graft and the proximal common femoral artery. If there is a concern that complete dissection of the common femoral artery is precarious because of scar tissue, control may be best obtained with a balloon occlusion catheter or by treating the artery and the graft as one vascular “unit” and placing a vascular clamp across them both. The inguinal ligament can be incised if needed to provide adequate exposure. The proximal graft and femoral artery should be dissected free from the surrounding scar and encircled with vessel loops or umbilical tape. Sharp dissection continues on the lateral and medial sides of the common femoral artery to identify the bifurcation, the superficial femoral artery, and the profunda femoris artery. Each vessel can be dissected completely to be encircled with vessel loops for control or handling in preparation of placing clamps.

If the scar tissue is too severe to safely dissect, a retroperitoneal or midline incision should be considered to expose the abdominal component of the graft for proximal control. Distal control can be obtained through an incision lateral to the sartorius muscle. Mobilizing the sartorius medially and incising the deep fascia exposes the superficial femoral and the profunda femoris arteries. Another alternative for distal vascular control is to open the aneurysm and place balloon occlusion catheters in the distal vessel lumen ( Fig. 35-1 ).

Vascular control of a noninfected anastomotic common femoral artery. Inflammation and scar tissue may prohibit control with clamps alone. This illustration demonstrates proximal clamps on the common femoral artery and graft limb, and the aneurysm is opened. Balloon occlusion catheters have been placed in the superficial femoral and profunda femoris arteries for control.