Saving Infected Aortic Grafts for a Lifetime
abstract & commentary
Synopsis: Five patients with proven or suspected aortic grafts who were not fit enough for surgery were managed with suppressive antimicrobial therapy.
Source: Roy D, Grove DI. Efficacy of long-term antibiotic suppressive therapy in proven or suspected infected abdominal aortic grafts. J Infect 2000;40:184-204.
Roy and grove from queen elizabeth hospital in Woodville, South Australia, report the non-surgical management of five patients of whom "Two patients developed infection of an established graft, two patients had a graft inserted into an infected area and one patient was thought to be at high risk of developing infection of a recently placed graft." This infection usually has a high mortality rate and the "benchmark" of therapy has been full excision of the implant. Of the five patients, two had infection with Staphylococcus aureus, one with S. auricularis, and one with S. hemolyticus. None of the staphylococci were methicillin resistant. Three of the patients were treated with a long-term oral semisynthetic penicillin (flucloxacillin that in some cases here was tailed off from 1 g/three times daily to 500 mg/twice daily). The fourth patient had a pathogenic S. hemolyticus susceptible to ampicillin and was treated with amoxycillin 1 g three times a day that was tapered to 500 mg twice daily. The fifth case had an Enterococcus faecalis isolated from blood cultures and was treated with long-term amoxycillin/clavulanic acid 500 mg/125 mg for 32 months.
None of these patients was considered fit enough to undergo surgery. Thus, Roy and Grove argued that suppressive antimicrobial therapy was the only alternative. The five reported patients did well, having survived for a mean of 32 months. No morbidity developed in any of the five patients. ESR, and C-reactive protein, when obtained, generally dropped over time.
Comment by Joseph F. John, MD
Aortic grafts develop infection in about 2% of patients treated. While not a particularly high rate, these infections are devastating and traditionally have been treated with excision and replacement, adding to morbidity and mortality. This report is particularly important since few data like these have been reported in the literature. A report by Bouhoutsos and colleagues1 was one of the few found by Roy and Grove to use antibiotics alone to treat their patients’ graft infection, although these four patients had infections that developed within three weeks of surgery.
Many of us practitioners have had experience with therapy of graft infections prior to excision, although the presence of graft infection in some of their patients could be questioned. Knowing when to stop antibiotics remains the most difficult issue. From the work of Roy and Grove, one alternative now may be never to stop antibiotics, and to manage the patient nonoperatively, particularly if the patient is a poor surgical risk, and can be compliant with oral antimicrobial therapy. Also interesting in this report is the ploy to taper the ß-lactam used for these patients to tolerable schedules, usually twice a day.
The range of therapy in this report is 30 to 72 months; so both physician and patient must be, yes, patient. A declining sedimentation rate or CRP may give confidence to the therapeutic regimen. In this age of antimicrobial resistance, two other considerations emerge. First, many of the staphylococcal graft infections in this country are going to be caused by methicillin-resistant staphylococci. Australia has a national program for controlling methicillin resistance, and it really pays off when, as in these cases, older agents can be used long-term to treat these graft infections. Second, patients receiving long-term antimicrobial suppressive therapy are clearly at risk for harboring resistant bacteria. So, the true long-term risks of suppressive therapy remain unknown. For the individual patients, it is clearly worth the risk.
Reference
1. Bouhoutsos J, et al. Infected synthetic arterial grafts. Br J Surg 1974;61:108-111.
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