Diagnosis and management of aortic graft infection.

This report summarizes the currently available methods of diagnosing and treating aortic graft infections. These infections tend to present in subtle ways; therefore, no single diagnostic test is appropriate for all patients. Available imaging techniques have a wide spectrum of sensitivity and specificity. Complementary tests may be necessary to confirm the diagnosis, determine the extent of infection, and assist with operative planning. Once localized, the infectious organism should be cultured. Treatment should be highly individualized and determined by the virulence of the infectious organism, the extent of infection, and the medical status of the patient. Whereas graft excision and extra-anatomic revascularization remains the "gold standard" for treatment of aortic graft infection, the use of in situ replacement with autogenous vein has been shown to be an excellent alternative. In very limited circumstances, in situ replacement with allograft or rifampin-bonded prosthesis may be acceptable.     

Postinjury abdominal aortic graft infection: documentation and successful management

This case report illustrates that postinjury aortic grafts may become infected. A high index of suspicion should be maintained in the postoperative period to detect these infections as early as possible. Prevention and treatment strategies will continue to evolve.     

Long-term results following surgical management of aortic graft infection

Between January 1970 and June 1988, a total of 45 patients with aortic prosthetic graft infection underwent removal of the infected aortic prosthesis. In addition, 36 of these patients also underwent revascularization via an extra-anatomic bypass. We analyzed the early and long-term results with respect to survival, limb salvage, freedom from infection, and extra-anatomic graft patency. The 30-day mortality was 24% (11/45), and the amputation rate was 11% (8/73). During a mean follow-up of 36 months (range, 2 to 144 months), 80% (24/30) of the patients remained free of infection and are considered cured. Infection in the extra-anatomic bypass graft was the most common cause of recurrent sepsis and the leading cause of late amputations (four of seven). By life-table methods, 1-year survival was 63% and 5-year survival was 49%. Limb salvage rates at 1 and 5 years were 79% and 66%, respectively. The primary patency rate of extra-anatomic bypass was 43% at 3 years, with the secondary patency rate improved to 65%. These early and late results are in marked contrast to the natural history of untreated aortic graft infection. Nonetheless, a perioperative mortality rate of 24%, a 5-year limb loss rate of 33%, and 3-year graft thrombosis rate of 35% are testimony to the serious nature of aortic graft infection and the need to develop better methods to prevent this complication.     

Clostridial aortic graft infection

Aortic graft infection represents one of the most formidable challenges encountered by the vascular surgeon. Current principles of treatment are based on experience primarily derived from infection with Staphylococcus and enteric bacteria. Anaerobic prosthetic infection is a case event. Infection with Clostridium has heretofore been reported only twice. An additional case of clostridial infection of an aortic prosthesis is presented with review of the literature. Its clinical significance and management are discussed.     

Management of the aortic graft infection

Prosthetic graft infection is a life-threatening complication in aortic surgery. Ectopic gas, perigraft fluid collection, and pseudoaneurysm can be detected by CT scanning. In cases of graft-enteric fistula, the prosthetic material can sometimes be observed using gastroduodenoscopy. Several methods of treatment have been attempted clinically. Removal of the infected graft and additional extra-anatomic bypass are associated with acceptable surgical outcomes, although the mortality rates are high because of persistent infection or aortic stump rupture. In-situ prosthetic graft replacement or omental transposition has also been attempted, although control of the infection has rarely been achieved. In-situ replacement with a cyropreserved aortic allograft considered to be resistant against infection has recently been performed. The immunological rejection or long-term patency rate of aortic allografts is unknown. However, this technique appears to be a useful option for the management of aortic graft infection.     

Management of aortic graft infection

BACKGROUND: The optimal method of operative treatment of prosthetic aortic graft infection (PAGI) has been the subject of debate; incidence rates of PAGI are low. Diagnosis of PAGI can be difficult. The aim of this retrospective study is to evaluate our results in treating PAGI in order to try and optimize the treatment of this grave problem. METHODS: Thirty-eight patients (median age 68.5 years) were treated for PAGI between 1991 and 2000. Management of PAGI was performed with total graft excision and simultaneous extra-anatomic bypass (n=18), total graft excision and in situ repair with a Rifampicin-soaked gelatin-impregnated prosthetic aortic graft (n=8), or a partial excision with in situ repair (n=11). In 1 patient, only local irrigation was performed. The median follow-up was 45 months. RESULTS: Clinical presentation of PAGI (median interval 3 years) was: discomfort/pain (n=14), gastro-intestinal bleeding (n=11), persisting fever (n=8), or a non-healing wound (n=5). The primary patency rate in patients with extra-anatomic bypass was 67% at 6 months follow-up. In patients with other surgical reconstructions no graft occlusion was encountered. Overall amputation rate was 5%. Recurrent infection of the graft was 15%. The overall early mortality rate in this study was 21%. CONCLUSIONS: The diagnosis of PAGI is difficult and should be based on a combination of clinical symptoms, laboratory findings and imaging techniques. There are several treatment options that should be tailored to the extent of infection and the patients' physical condition. In a selected group of patients partial excision of the infected graft only can be justified.     

Successful treatment of ascending aortic graft infection after operation for acute aortic dissection with peripheral malperfusion

Mediastinitis with infection of an ascending aortic graft is hard to heal and is a highly fatal complication. We had a patient in whom mediastinitis with infection of such a graft as well as an ascending aorta–femoral artery bypass graft developed after the initial operation for type A aortic dissection accompanied by peripheral malperfusion. We treated it successfully by inserting a stent into the true lumen of the thoracoabdominal aorta and using a cryopreserved homograft to replace the infected ascending aortic fabric graft.     

Contemporary management of infrarenal aortic graft infection: early and late results in 82 patients

Management of aortic graft infection (AGI) remains contentious. The purpose of this study was to evaluate factors of clinical significance which influence the outcome of different treatment modalities for AGI. From 2000 to 2008, 82 consecutive patients were treated for AGI. In situ reconstruction (ISR) was performed in 63 patients with various conduits, extra-anatomic reconstruction (EAR) in 11, conservative treatment in five and resection without reconstruction in three. The perioperative mortality rate for the series (33%) was similar for EAR and ISR and was higher in patients with secondary aortoenteric fistula (P < 0.001) in those undergoing emergency aortic reconstruction (P < 0.001) and in AGI caused by virulent organisms (P < 0.05). Fifteen (27%) of the surviving patients developed a recurrence of infection (RI). EAR patients were more exposed to RI (P < 0.04). In conclusion, ISR may be more appropriate for AGI, but this study cannot draw a conclusion relating to the optimal conduit for ISR.     

Improved results with conventional management of infrarenal aortic infection.

PURPOSE: Interest in alternative methods, such as autogenous vein grafts and aortic allografts, for the management of infrarenal aortic infection (IRAI) has been stimulated by the historically disappointing results with conventional surgical management. Recently, there have been dramatic improvements in the results of axillofemoral bypass grafting (AXFB) followed by excision of the IRAI that have gone relatively unrecognized. The purpose of this report is the presentation of modern-day results in the treatment of IRAI with conventional surgical methods. METHODS: From January 1, 1983, through June 30, 1998, patients with IRAI underwent treatment with AXFB and complete excision of the IRAI. The patients were followed for survival, limb salvage, and AXFB graft patency. The results were tabulated with life-table methods. RESULTS: During the 15-year study period, 60 patients (51 men, nine women; mean age, 68 years) underwent treatment for IRAI (50 graft infections, including 16 graft-enteric fistulae, and 10 primary aortic infections). The mean follow-up period was 41 months. The perioperative mortality rate was 13% (12% for graft infection, and 20% for primary infection). The overall 2-year and 5-year survival rates were 67% and 47%, respectively. The limb salvage rates at 2 and 5 years were 93% and 82%, respectively. The 5-year primary AXFB graft patency rate was 73%. CONCLUSION: These results show an improvement with the conventional management of IRAI equal or superior to those results reported with alternative methods, including femoral vein grafts or aortic allografts. These results should be regarded as the modern standard with which alternative therapies can be compared.     

Improved management of infrainguinal bypass graft infection with methicillin-resistant Staphylococcus aureus

BACKGROUND: There is considerable debate over the management of infected infrainguinal grafts. This report describes recent experience in this field and documents the change in clinical practice needed to deal with methicillin-resistant Staphylococcus aureus (MRSA). METHODS: All infected infrainguinal grafts between January 1991 and July 1997 were reviewed. In the light of the findings, clinical practice was modified considerably. A further 1 year was audited prospectively up to August 1998. RESULTS: Twenty-six patients were treated for 27 infrainguinal graft infections (25 prosthetic, two vein). Twenty were treated by complete graft excision as the initial therapy; graft preservation was attempted in six patients. Before 1995, the infecting organisms were predominantly Pseudomonas aeruginosa or methicillin-sensitive staphylococci. Subsequently all 14 patients treated up to 1997 had infection with MRSA. The overall amputation rate was 17 of 26; ten amputations were in patients with MRSA. Four patients died, all with MRSA sepsis. As a result of this experience a policy of complete isolation was adopted for all patients infected with MRSA. In the 12 months since this policy was introduced, 77 infrainguinal grafts (61 vein, 16 prosthetic) have been inserted. Two grafts (3 per cent) have become infected, necessitating graft excision and amputation. CONCLUSION: MRSA infection of an infrainguinal graft is a serious complication with high associated amputation and mortality rates. Isolation and barrier nursing appeared to contain the problem.     

Conservative treatment of aortic graft infection

Conservative, nonresectional management of aortic graft infections is the optimal management for selected patients with aortic graft infections. The best candidates are those patients who have significant comorbidities, or where the existing aortic graft is in a location that precludes excision without causing a high likelihood of morbidity and/or mortality, such as thoracoabdominal and aortic arch grafts. When considering the conservative approach, computed tomographic angiography, supplemented by Indium(111) leukocyte scanning, is the best combination of diagnostic tests. Contraindications to a conservative approach are infected anastomotic aneurysms, graft-enteric fistulas, and suture-line hemorrhage. Needle aspiration of perigraft fluid or phlegmon, under ultrasound or computed tomography guidance, is useful to both culture the infection and provide drainage. A conservative approach should not be considered when the graft infection is due to invasive Gram-negative organisms, such as Pseudomonas or Salmonella species. Once a conservative approach is selected as the best treatment option, drainage of an infected perigraft space is critical to success, and can be performed either percutaneously or with open surgery, whether an endograft or surgically placed graft is in place. If open drainage is required, the perigraft space should be debrided and catheters placed for long-term antibiotic irrigation. With continuous antibiotic irrigation until the cultures are negative, followed by life-long oral antibiotics, there are multiple case reports and small series of long-term survivors. Whether the aortic graft infection is cured or controlled is debated, but outcomes for high-risk patients and those with grafts in critical vascular beds are often superior to a high-risk surgical graft resection.     

Redo aortic grafting after treatment of aortic graft infection

Purpose: This study was performed to determine the indications, operative strategy, and hemodynamic benefit of redo aortic grafting procedures after earlier excision of an infected aortic graft.Methods: Among 164 patients treated for aortic graft infection, 15 later underwent redo aortic grafting procedures an average of 18 months (range, 1 to 59 months) after removal of an infected aortic graft. Redo grafting procedures were performed for leg ischemia (n = 11) or infection (proven, n = 3; suspected, n = 1). The new aortic graft originated either from the distal thoracic aorta (n = 5) or from the juxtarenal aortic stump (n = 10). Follow-up averaged 56 months (range, 7 to 110 months).Results: All patients survived the redo grafting procedure. In the eleven patients who had ischemic symptoms, redo grafting procedures uniformly resulted in symptomatic improvement with an increase in ankle-brachial indexes (0.78 ± 0.34 vs 0.50 ± 0.29; p = 0.02). A graft limb occlusion developed in two of these patients (3 and 6 months), but no limbs were amputated. In the four patients who had proven or suspected extraanatomic bypass graft infection, there was one graft limb occlusion (29 months) and one amputation (17 months). Overall, recurrent graft infection occurred in three of 15 patients and may be more frequent in patients who have a proven extraanatomic bypass graft infection (2 of 3 vs 1 of 12; p = 0.08). Infection accounted for two of the three graft limb occlusions and two of the three late deaths. Recurrent infection was not associated with early (<1 year) regrafting procedures, and culture results did not correlate with the microbiologic features of the primary infection.Conclusions: Redo aortic grafting procedures can be performed safely and at relatively early intervals (6 to 12 months) after removal of the infected aortic graft. The procedure reliably relieves ischemic symptoms of the hemodynamically inadequate extraanatomic bypass graft. Reinfection remains a risk after redo aortic grafting procedures, particularly when treating established extraanatomic bypass graft infection. (J Vasc Surg 1996;24:328-37.)     

Conservative surgery for aortic graft infection

Surgery for aortic graft infection is a major challenge often characterized by the need for ingenuity and improvisation. Traditional treatment is by total graft excision and extra-anatomic bypass. In situreplacement of the infected graft using either autogenous tissue or antibiotic-impregnated Dacron is effective in selected cases but it is not clear when such conservative treatment may be employed. Graft excision and thorough débridement of infected tissue are important, whichever technique is used. It would seem unwise to perform in situ reconstruction unless the remaining operative field is free from contamination. When in situ replacement is selected, a rifampicin-soaked Dacron graft is the easy option, but large studies will be needed to determine whether this is a suitable long-term alternative to conventional treatment.     

Confirmation of infection of an aortic graft

The presentation of an aortic graft infection may be dramatic in the form of an aortoenteric fistula or drainage of pus from the wound. Some cases may be more subtle with presentations of fever of unknown origin. Prior to embarking upon major operative repair for these suspected lesions, it is essential to confirm the presence of infection. Under CT control, a fine needle may be inserted into the peri-graft space, and cultures may be obtained. Further confirmation may be achieved by an injection of a small amount of contrast material which will demonstrate lack of incorporation of the graft into surrounding tissues. Prior confirmation of graft infection permits a staged procedure to repair this technique is illustrated with a case history.     

Conservative treatment of major aortic graft infection

Major infections of Dacron aortic grafts involving the proximal anastomosis or the whole graft are rare but lethal. Traditional surgical treatment involves radical excision of the graft and extra-anatomic revascularisation of the lower limbs, and carries a forbidding mortality and complication rate. This paper describes an alternative conservative approach used on four patients, three of whom appear to have been successfully treated by continuous antibiotic irrigation of the prosthesis without removal of the graft, whilst the fourth died 42 months later of recurrent graft infection. This is the first time that prolonged survival has been reported following conservative treatment of major graft infection. The authors believe this method may offer substantial advantages over the traditional surgical treatment for this dreaded complication of aortic surgery.     

Antibiotic therapy of aortic graft infection: treatment and prevention recommendations

Surgical site infection (SSI) after aortic intervention, an uncommon but serious vascular condition, requires patient-specific antibiotic therapy. Effective treatment and prevention requires the vascular surgeon to be cognizant of changing SSI microbiology, advances in antibiotic delivery, and patient characteristics. The majority of aortic graft infections are caused by Gram-positive bacteria, with methicillin-resistant Staphylococcus aureus now the prevalent pathogen. Nasal carriage of methicillin-sensitive or methicillin-resistant S aureus strains, diabetes mellitus, recent hospitalization, a failed arterial reconstruction, and the presence of a groin incision are important SSI risk factors. Overall, the aortic SSI rate is higher than predicted by the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance risk category system; ranging from 5% after open or endovascular aortic interventions to as high as 10% to 15% after aortofemoral bypass or uni-aortoiliac grafting with femorofemoral bypass. Perioperative measures to reduce S aureus nares and skin colonization, administration of antibiotic prophylaxis, meticulous wound closure/care, and therapy directed to optimize patient host defense regulation mechanisms (eg, temperature, oxygenation, blood sugar) can minimize SSI occurrence. Antibiotic therapy for aortic graft infection should utilize bactericidal drugs that penetrate bacteria biofilms and can be delivered to the surgical site both parenterally and locally in the form of antibiotic-impregnated beads or prosthetic grafts.     

Antibiotic-impregnated beads for the treatment of aortic graft infection

Infection of a prosthetic graft after replacement of the ascending aorta is an uncommon but life-threatening complication of surgery. We report the use of antibiotic-impregnated calcium sulfate beads in a patient with ascending aortic graft infection to provide localized, high-dose therapy to the infected region. Perigraft placement of antibiotic beads provides an alternative method for the treatment of aortic graft infection.     

Surgical management of ascending aortic graft infection. No-sedation-technique for open mediastinal irrigation.

Two patients with ascending aortic graft infection were successfully treated. The first patient underwent ascending aortic replacement using a Dacron graft for aortic dissection, and developed graft infection. After 25 days' open mediastinal irrigation, allograft replacement and rectus muscle flap transfer were performed. The second patient underwent translocation of the aortic valve with a composite graft for calcific aortic stenosis, and developed graft infection. After 29 days' open irrigation, omental and rectus muscle flap transfer were performed. We were able to perform long-term open mediastinal irrigation using our original no-sedation-technique without any severe complication such as bleeding or secondary infection. We believe this technique is helpful in the management of severe ascending aortic graft infection.