The benefits of patch closure over primary arteriotomy closure in the reduction of the risk of peri-operative stroke, internal carotid artery thrombosis and recurrent stenosis have widely established the use of patches in carotid surgery. Today, available patching options include autologous (usually saphenous vein), polytetrafluoroeth-ylene (PTFE), polyester (Dacron, DuPont, Wilmington) and bovine pericardium patches. Vein patches offer the benefit of lower risk of infection, which is outweighed by a higher risk of rupture, poor predictability of diameter size, longer operative time, groin complications and depletion of sources for future vascular reconstruction. The simplicity of a readily available prosthetic patch graft, which prevents narrowing of a small-diameter internal carotid artery and offers a shorter operative time, has led to the widespread acceptance of prosthetic patch angio-plasty in carotid surgery .
Infection is an extremely rare complication of carotid surgery, ranging between 0.33% and 1.8% in the largest series published after the year 2000. The majority of reported cases of infections concern Dacron patches, perhaps reflecting their more frequent use compared to PTFE patches. Series in which vein patches were used report extremely low rates of infections, although few case reports concern autologous material infectious complications such as pseudoaneurysm formation. In all the aforementioned studies, antibiotic prophylaxis was administered prior to the procedure . Five episodes of infected false aneurysm formation have been reported in a series when primary closure of arteriotomy without patching was performed without primary antibiotic prophylaxis .
The time of presentation of the infection varies from 10 days to 41 months, but 62% of the reported infections were apparent within 3 months from surgery (early infection). Signs of early infections may be local, such as tenderness and swelling, cellulitis, abscess, pseudoaneurysm, massive haemorrhage from the vessel and patch rupture, or systemic, such as sepsis syndrome. Early carotid patch infections are often heralded by surgical wound infection . S. aureus and viridans group streptococci predominate (37.5% and 31.3% of infections respectively), while Gram-negative bacilli, Propionibacterium acnes and Bac-teroides fragilis are encountered less frequently. Streptococci, which are respiratory colonizers, invade the surgical site due to its proximity to the respiratory mucosa. In late patch infections, draining sinus and pseudoaneurysm formation predominate the clinical presentation. Coagu-lase-negative staphylococci are isolated in more than 80% of cases . Diagnosis of CPI is established peri-opera-tively, with sampling of purulent material or fluid collection or patch material for cultures revealing the infecting pathogen in 87% of cases. Doppler ultrasound, CT, MRI, MRA and angiography are helpful in the diagnosis ofCPIs [68, 82].
Treatment of PCPI requires total patch removal, extensive local debridement and, according to some specialists, use of antibiotic-impregnated sponges. Antimicrobial treatment varies in different series, from 2 to 6 weeks after prosthesis removal, but 4-6 weeks of treatment as described in the general part of this chapter is generally recommended. Replacement with autologous tissue is preferred in the majority (92%) of revascularization procedures, either as vein in situ replacement or as vein extra-anatomic by-pass. A small minority of patients cannot escape carotid artery ligation, a technique with a 50% rate of postoperative death or serious stroke . The use of rifampin-bonded synthetic carotid patches has been very promising in recent studies, provided that the patient has no systemic sepsis and the affected vessel is patent. In redo carotid surgery after infection, low death or relapsing graft infection rates have been reported, but complications such as stroke, cranial nerve injury, myo-cardial infarct and epidural abscess may sometimes be encountered [3, 7,15, 80].
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