reconstructions due to the inferior patency of extraanatomic reconstructions and the risk of aortic stump

rupture.74–78 O’Connor performed a systematic review of the literature to compare the various methods

of reconstruction, comparing extraanatomic bypass, rifampin-soaked prostheses, cryopreserved

allografts, and autogenous venous reconstructions.106 Adverse events were more than 50% more

frequent with extraanatomic bypass, compared to in situ reconstruction. The lowest event rates were

noted with rifampin-soaked prosthetic bypasses. Early and late mortality was most likely after

extraanatomic bypass. Autogenous venous reconstructions provided the lowest rate of reinfection,

followed closely by cryopreserved allografts. Conduit failure was most likely with extraanatomic

bypasses. The patient numbers were too low to compare the patency of rifampin-soaked bypasses with

other reconstructions. Major amputation was most likely with either extraanatomic bypass or

autogenous venous reconstructions. Table 88-1 summarizes the authors selected studies reporting the

outcomes of various reconstructions in aortic infections.

NONAORTIC ARTERIAL AND GRAFT INFECTIONS

Lower Extremity Arterial Infections

Lower Extremity Graft Infections

The nonoperative management of Szilagyi III wounds was described previously. Older studies show that

lower extremity bypass graft infections carry a postoperative major amputation and mortality rate of

nearly 50% due to the underlying atherosclerotic disease burden.107 These patients often do not have

other conduit suitable for bypass, which is a major impetus for graft preservation strategies for infected

extremity bypass grafts. The use of local debridement with adjunctive vacuum-assisted closure and

muscle flaps has yielded promising results. Siracuse cited an estimated 1-year limb salvage rate of 71%,

which was attributed to the graft preservation techniques described above.17

Cryopreserved human allograft veins have been touted as an alternative if a prosthetic bypass graft

must be removed for infection. Unfortunately, human allograft veins have yielded relatively poor

results. In a series of bypasses for critical limb ischemia using cryopreserved greater saphenous vein,

primary patency at 1 and 3 years was 27% and 17%, respectively.108 Amputation-free survival at 1 and

3 years was 43% and 23%, respectively. Cadaveric vein grafts are expensive, ranging between $7,000

and $7,500. In view of the outcomes and cost, the use of cryopreserved veins must be weighed against

the outcomes of graft preservation techniques on a case-by-case basis.

Infected Common Femoral Artery Pseudoaneurysms

The management of infected common femoral artery pseudoaneurysms diverges from the management

of infected pseudoaneurysms in other anatomic locations. The most frequent clinical scenarios involve

infection after a history of recent arterial catheterization or intravenous drug abuse. The incidence of

infection after cardiac catheterization is less than 1%, although the use of arterial closure device

increases the risk due to the presence of a foreign body.109 Aggressive debridement, removal of the

closure device, and revascularization remains the mainstays of therapy. In situ repair with autogenous

greater saphenous or femoral vein is preferred if arterial replacement is necessary.27,110 A rotational

muscle flap may be necessary for graft coverage in some cases. Occasionally, in situ repair may not be

advisable due to the quality of the arteries or the surrounding tissue. Ligation of the native arteries in

the groin and an extraanatomic bypass, such as an obturator bypass, may be preferable.111 Ligation of

the common femoral artery without reconstruction is utilized as a last resort and is less likely to

threaten the limb if the femoral bifurcation remains intact.112

Conversely, infected common femoral artery pseudoaneurysms secondary to intravenous drug abuse

should be preferentially managed with aggressive arterial and soft tissue debridement and ligation of all

of the involved arteries. Immune suppression due to malnutrition and human immune deficiency virus

infections, delayed presentation, and patient recidivism make arterial reconstruction hazardous in this

setting. Reddy showed that ligation of the common, superficial, and profunda femoral arteries is

associated with a 33% major amputation rate.113 Rates of major amputation are very low in other

series, with some authors reporting zero amputations in their series.114,115 Claudication is almost

universal, however with debridement and femoral artery ligations.27 Some authors recommend limiting

revascularization attempts to patients with absent pedal Doppler signals after ligation of the femoral

vessels, whereas others recommend amputation for all subjects with infected pseudoaneurysms due to

intravenous drug abuse.116

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Table 88-1 Complications Associated with Different Methods of Aortic

Reconstruction after Aortic Graft Excision, Based on Selected

Publications

Arterial Infections in Other Sites

Carotid patch infection is a rare, but dreaded occurrence. Management entails removal of the patch,

wide debridement, and primary closure of the artery versus vein patch closure. Interposition grafting

with autogenous vein is often necessary after the artery is debrided adequately. Occasionally ligation of

a bleeding, infected artery is necessary as a life-saving intervention.18 In a series of carotid patch

infections, the stroke rate after debridement and reconstruction was 8.1% and increased to 14% when

carotid ligation was necessary.18 Endografting is an acceptable option to control hemorrhage and permit

stabilization and evaluation for definitive surgery.117

Case reports and small case series of infected pseudoaneurysms of the superior mesenteric, celiac, and

splenic arteries have been reported.118,119 Treatment is individualized by the patient’s comorbidities and

anatomy. Infected visceral artery aneurysms are prone to rapid growth and rupture.118,119 Arteriography

is often helpful to delineate the anatomic relationship of the aneurysms to nearby branch vessels and to

define the quality of the collateral circulation. Excision, debridement, and arterial reconstruction with

autogenous conduit remain the gold standard for infected pseudoaneurysms of main arterial trunks.

Resection and arterial ligation may be an option in some cases, depending on the anatomic location due

the abundant collateral circulation between the mesenteric arteries and branches.120 Coil embolization

and long-term antibiotic therapy should be reserved for surgically inaccessible aneurysms, such as

intrahepatic mycotic pseudoaneurysms, since coils may become infected.121,122

ANTIBIOTIC THERAPY

Unfortunately, there are no guidelines directing the type, dose, duration, or route of administration of

antibiotics in treating arterial infections. This reflects the wide spectrum of causal organisms that are

found in arterial graft infections, with approximately one-third of subjects having polymicrobial

infections. Moreover, physician preference and patient tolerance of antibiotic regimens vary

considerably. In addition, culture-directed therapy is not always possible since nearly 40% of patients

have negative cultures, presumably due to preoperative broad-spectrum antibiotic therapy.4 Finally, the

consequences of a reinfection are dire, so there is a tendency among physicians to overprescribe

antibiotics.

Initial broad-spectrum antibiotics should include agents with activity against gram-positive bacilli,

gram-negative rods, and anaerobes, as these are the most prevalent organisms in graft infections.

Currently our preferred combination therapy is vancomycin, piperacillin/tazobactam, and

metronidazole. Blood cultures and graft and tissue cultures should be obtained to direct therapy.

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Recommendations for the duration of antibiotics vary widely, ranging from 2 to 8 weeks after graft

excision. If a graft or stent is not fully excised, indefinite antibiotic therapy should be considered.

Fungal infections are particularly difficult to eradicate and may require the use of micafungin (FK463)

due to the increasing incidence of resistance to fluconazole and its related molecules.123

PREVENTION OF SECONDARY ARTERIAL INFECTIONS

Meticulous surgical technique is critical to minimizing arterial graft infections. Judging from the

microbial flora associated with graft infections, intraoperative contamination and surgical site infections

are the most likely sources of contaminations that result in arterial graft infections. Adherence to all

perioperative guidelines for reducing surgical site infections is important, but the use of prophylactic

systemic antibiotics appears to be critically important. A recent meta-analysis and systematic review

performed by Stewart concluded that prophylactic systemic antibiotics decreased the risk of wound and

early graft infection for peripheral arterial reconstruction.124 No benefit was seen in continuing

antibiotics for greater than 24 hours, prophylactic rifampin-bonding to the grafts, suction groin wound

drainage, or preoperative bathing with or without antiseptic agents.

CONCLUSIONS

Primary and secondary arterial infections constitute a myriad of some of the most technically,

intellectually, and emotionally challenging cases that vascular surgeons may encounter in clinical

practice. For aortic arterial infections, there is no consensus regarding the optimal method of in situ

reconstruction. Autogenous vein reconstruction may be the most resistant to recurrent infection and

most cost effective, but requires an additional, lengthy procedure for vein harvest. Reconstruction with

either antibiotic- or silver-impregnated grafts may also be a reasonable alternative, but appears to have

a higher rate of reinfection compared to the alternatives. Cryopreserved allografts have improved since

their initial development, but are still hampered by a minority of hemorrhagic complications and

pseudoaneurysmal degeneration. Moreover, cryopreserved allografts are considerably more expensive

than the other alternatives. Extraanatomic bypass remains a viable alternative for patients unable to

undergo a more extensive operation. Endovascular stent grafts are excellent tools to stabilize patients

with hemorrhagic complications of arterial infections prior to definitive surgery. Arterial infections in

other locations utilize the same principles of wide excision and debridement, arterial reconstruction, and

appropriate antibiotic coverage whenever technically feasible.

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