The results of in situ prosthetic replacement for infected aortic grafts.

BACKGROUND: Treatment of aortic graft infection with graft excision and axillofemoral bypass may carry an increased risk of limb loss, aortic stump blowout, and pelvic ischemia. A review of patients with aortic graft infection treated with in situ prosthetic graft replacement was undertaken to determine if mortality, limb loss, and reinfection rates were improved with this technique. METHODS: The clinical data of 25 patients, 19 males and 6 females, with a mean age of 68 years (range 35 to 83), with aortic graft infection, treated between January 1, 1989, and December 31, 1998, by in situ prosthetic graft replacement were reviewed. Follow-up was complete in the 23 surviving patients and averaged 36 months (range 4 to 103). RESULTS: Twenty aortofemoral, 3 aortoiliac, and 2 straight aortic graft infections were treated with excision and in situ replacement with standard polyester grafts in 16 patients (64%), or with rifampin-soaked collagen or gelatin-impregnated polyester grafts in 9 patients (36%). Fifteen patients (60%) had aortic graft enteric fistulas, 8 patients (32%) had abscesses or draining sinuses, and 2 patients (8%) had bacterial biofilm infections. Thirty-day mortality was 8% (2 of 25). There were no early graft occlusions or amputations. There was one late graft occlusion. There were no late amputations. The reinfection rate was 22% (5 grafts). All reinfections occurred in patients operated upon for occlusive disease. Only one reinfection occurred in the rifampin-soaked graft group (11% versus 29%, P = NS). Reinfection tended to be lower in patients with aortoenteric fistulas and without abscess. Autogenous tissue coverage provided statistically significant protection against reinfection. There were no late deaths related to in situ graft infection. CONCLUSIONS: Patients treated with in situ graft replacement had an 8% mortality and 100% limb salvage rate. Reinfection rates were similar to those of extra-anatomic bypass, but a trend of lower reinfection rates with rifampin-impregnated grafts was apparent. Patients with aortoenteric fistula and without abscess appear to be well treated by the technique of in situ prosthetic grafting and autogenous tissue coverage.     

In situ repair of mycotic abdominal aortic aneurysms with rifampin-bonded gelatin-impregnated Dacron grafts: A preliminary case report

Treatment of mycotic aortic aneurysm by excision and extraanatomic bypass is difficult to apply when the infectious process involves the visceral arteries. On the basis of experimental studies in our laboratory that demonstrated prolonged antistaphylococcal activity of rifampin-bonded, gelatin-impregnated Dacron grafts after implantation in the arterial circulation, this conduit was successfully used for in situ replacement of a native aortic infection in two patients. Both patients had fever, leukocytosis, abdominal or back pain, and a computed tomographic scan that demonstrated contained rupture of a mycotic aneurysm. Preoperative computed tomography guided aspiration and culture of periaortic fluid from one patient grew Staphylococcus aureus. Treatment consisted of prolonged (6 weeks) culture-specific parenteral antibiotic therapy, excision of involved aorta, oxychlorosene irrigation of the aortic bed, and restoration of aortic continuity by in situ prosthetic replacement. A preliminary right axillobifemoral bypass was performed in the patient who had an infection involving the suprarenal and infrarenal aorta. In both patients intraoperative culture of aorta wall recovered S. aureus. Patients were discharged at 20 and 21 days. Clinical follow-up and computed tomographic imaging of the replacement graft beyond 10 months after surgery demonstrated no signs of residual aortic infection. In the absence of gross pus and frank sepsis, the use of an antibiotic-bonded prosthetic graft with antistaphylococcal activity should be considered in patients who have arterial infections caused by S. aureus when excision and ex situ bypass are not feasible. (J Vasc Surg 1996;24:472-6.)     

Expanded application of in situ replacement for prosthetic graft infection

PURPOSE: The purpose of this study was to analyze the outcome of an individualized treatment algorithm for prosthetic graft infection, including the application of in situ graft replacement, based on clinical presentation, extent of graft infection, and microbiology. METHODS: There was a retrospective review (1991-2000) of 119 patients with 68 aortoiliofemoral or 51 extracavitary (infrainguinal, 19; axillofemoral, 16; femorofemoral, 16) prosthetic graft infections presenting more than 3 months (range, 3-136 months) after implantation/revision. The treatment algorithm consisted of graft excision with or without ex situ bypass grafts for patients presenting with sepsis or graft-enteric erosion, whereas in situ replacement (autogenous vein, rifampin-bonded polyester, polytetrafluoroethylene [PTFE]) was used in patients with less virulent gram-positive graft infection, in particular infections caused by Staphylococcus epidermidis. Outcomes (death, limb loss, recurrent infection) were correlated with treatment type and infecting organism. RESULTS: In situ replacement was used in 52% of aortoiliofemoral (autogenous vein, 10; rifampin-bonded polyester, 6; PTFE, 9) and 80% of extracavitary (autogenous vein, 26; PTFE, 9; rifampin, 6) graft infections. Total graft excision with ex situ bypass was performed in 34 patients, including 21 patients with graft-enteric erosion/fistula, with a 21% operative mortality and 9% amputation rate. In situ graft replacement was used to treat 76 graft infections with a 30-day operative mortality rate of 4% and an amputation rate of 2%. Graft excision alone was performed in nine patients with one 30-day death. Gram-positive cocci were the prevalent infecting organisms of both intracavitary (59% of isolates) and extracavitary (76% of isolates) graft infections. S epidermidis was the infecting organism in 40% of patients, accounting for the expanded application of in situ prosthetic replacement using a rifampin-bonded polyester or PTFE prosthesis. During the mean follow-up interval of 26 months, recurrent graft infection developed in 3% (1 of 34) of patients after conventional treatment, 3% (1 of 36) patients after in situ vein replacement, and 10% (4 of 40) patients after in situ prosthetic graft replacement (P >.05). Failure of in situ replacement procedures was the result of virulent and antibiotic-resistant bacterial strains. CONCLUSIONS: In situ replacement was a safe and durable option in most (64%) patients presenting with prosthetic graft infection. In situ replacement with a rifampin-bonded graft was effective for S epidermidis graft infection, but when the entire prosthesis is involved with either a biofilm or invasive perigraft infection, in situ autogenous vein replacement is preferred. Virulent graft infections presenting with sepsis, anastomotic dehiscence, or graft enteric fistula should continue to be treated with total graft excision, and if feasible, staged ex situ bypass graft.     

Implantation of antibiotic-releasing carriers and in situ reconstruction for treatment of mycotic aneurysm.

Four patients with mycotic aneurysm of the extracranial carotid artery, the innominate artery, the ascending aorta, and the infrarenal aorta were treated with local implantation of antibiotic-releasing carriers after resection of the aneurysm, excision of all infected tissue, and in situ reconstruction by prosthetic graft replacement in two patients and patch plasty in two patients. The patient with a mycotic aneurysm of the ascending aorta was operated on again 1 month after the first operation because of a second mycotic aneurysm located on the aortic arch. No early or late signs of recurrent infection were seen on clinical and laboratory postoperative follow-up done between 9 and 16 months or on duplex scan or computed tomography done at these times. Implantation of antibiotic-releasing carriers after débridement of all infected tissue and in situ reconstruction for treatment of mycotic aneurysm was performed successfully in four patients with this life-threatening condition.     

In situ replacement of vascular prostheses infected by bacterial biofilms

Late prosthetic graft infections are commonly the result of coagulase-negative staphylococci that survive within a biofilm on prosthetic surfaces and provoke perigraft inflammation. The indolent nature and microbiologic characteristics of bacterial biofilm infections coupled with the morbidity of graft excision and extraanatomic bypass grafting prompted us to use in situ graft replacement in 15 patients admitted to the hospital with 17 infected graft segments at a mean (+/- SEM) time interval of 70 +/- 16 months after graft implantation (n = 6) or revision (n = 9). Since 1986, 17 grafts (14 aortofemoral, 2 axillofemoral, and 1 femoropopliteal) infected by bacterial biofilms have been treated. Signs on admission included femoral pseudoaneurysm (n = 7), perigraft abscess (n = 6), or graft-cutaneous sinus tract (n = 4). No patient exhibited septicemia. At operation graft incorporation was absent and Gram's stain of perigraft exudate showed polymorphonuclear leukocytes but no bacteria. Culture of explanted graft material isolated coagulase-negative staphylococci (n = 12), Staphylococcus aureus (n = 1), and no growth (n = 2). All patients were successfully treated by a regimen that included parenteral antibiotics, removal of involved graft material, excision of inflamed perigraft tissue, and in situ replacement with an expanded polytetrafluoroethylene prosthesis. No deaths, graft thromboses, or deep wound infections occurred after operation. Recurrent graft infection did not develop during a follow-up interval that ranged from 5 to 50 months (mean, 21 months). Diagnosis of vascular prosthesis infection caused by bacterial biofilms can be based on signs at admission and operative findings. Complications of this perigraft infection can be eradicated by antibiotic administration, local debridement, and in situ graft replacement.     

Infected lower extremity extra-anatomic bypass grafts: Management of a serious complication in high-risk patients

To determine optimal management and outcome of infected extra-anatomic bypass grafts (EABG), we reviewed 28 patients (19 men and 9 women; mean age 70 years) treated over a 13-year period. Mean follow-up was 42 months. There were 16 axillofemoral (AF), 10 femorofemoral (FF), and two axillopopliteal (AP) grafts. Risk factors included previous prosthetic graft infection in 13 patients, enterocutaneous fistula in two, and mycotic aortic aneurysm in one. Initial management involved complete graft excision in 12 patients, partial graft excision in 10, and nonresectional therapy in six. Failure of nonresectional therapy and partial excision in three patients each required further operative intervention with graft excision. Reconstruction in patients eventually requiring graft excision (n=25) entailed placement of a new prosthetic AF or AP graft in eight, an autogenous FF graft in five, combined prosthetic AF and autogenous FF bypass in two, autogenous iliofemoral bypass in one, obturator bypass in one, or no reconstruction in eight. Four autogenous FF reconstructions thrombosed immediately postoperatively, and three prosthetic reconstructions became infected. The mortality rate was 18% (FF=20%, AF=19%, AP=0%). The amputation rate was 25% (AP=100%, AF=25%, FF=10%) and was higher without arterial reconstruction (56% vs. 12%,p=0.02). Two patients required hemipelvectomies and one had bilateral hip disarticulation. We conclude that EABG infections can be successfully treated but carry significant morbidity and mortality. Optimal management includes EABG resection and prompt revascularization, bearing in mind the risk of early thrombosis in autogenous grafts and reinfection in prosthetic grafts.Presented at the Thirteenth Annual Meeting of the Southern California Vascular Surgical Society, Coronado, Calif., September 16–18, 1994.     

Mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum: a case report of surgical management and review of the literature

We report a surgical case of mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum. The patient was first treated with an in situ prosthetic graft replacement. When the infection recurred 5 weeks after the aortic surgery, the patient was successfully treated by transposition of rectus abdominis muscle flap around the graft. Only 19 cases of mycotic aneurysm or aortic dissection caused by Clostridium septicum have been reported. Ten of 12 patients who underwent vascular surgery survived, whereas all 7 patients who did not undergo surgery died. Surgical treatment should be undertaken since the surgical results seem satisfactory.     

Use of superficial femoropopliteal vein for suprainguinal arterial reconstruction in the presence of infection

BACKGROUND: Conventional treatment of mycotic aneurysms or graft infections of the aortoiliac segment by in situ or extra-anatomic prosthetic reconstruction has a high mortality and morbidity rate, with a substantial risk of persistent graft infection. The use of autologous vein may reduce this. METHODS: Eleven patients with suprainguinal arterial infections including two with mycotic aortic aneurysms, four with aortic graft infections, four infected femorofemoral grafts and an infected axillofemoral graft were treated by debridement and in situ reconstruction with autologous superficial femoropopliteal vein. All patients received appropriate antibiotic therapy and were followed by regular postoperative duplex imaging. Preoperative femoral vein duplex imaging was performed in eight of the 11 patients. RESULTS: Ten of the 11 patients survived with a functioning graft and without limb loss or evidence of infection at 4-33 months. One patient died from myocardial infarction after operation. Three patients had minor swelling of one leg. Four patients required subsequent angioplasty of anastomotic stenoses detected by duplex surveillance. CONCLUSION: Superficial femoropopliteal vein is an excellent conduit for suprainguinal reconstruction in the presence of infection. Duplex imaging is useful for confirming the suitability of deep veins for use as a graft and for postoperative surveillance.     

Outcomes in the management of vascular prosthetic graft infections confined to the groin: A reappraisal

The management of vascular prosthetic graft infections confined to the groin continues to be controversial. To critically evaluate this problem, we reviewed the records of our vascular registry from December 1992 through February 1995 and found 17 incidences of groin sepsis involving a vascular prosthesis in 10 patients. These included a proximal prosthetic femoropopliteal bypass (n=6), an aortobifemoral graft limb (n=5), an ileofemoral bypass (n=3), a prosthetic femoral patch (n = 2), and an aortofemoral/femorofemoral bypass (n=1). The mean age of these patients was 65 years. Six patients were diabetic, four were on systemic steroids, and two were diabetic and on steroids. All infections were Szilagyi grade III including three in which the patients presented with local hemorrhage. Treatment consisted of irrigation, radical debridement with or without in situ graft replacement, and local rotational muscle flap coverage in nine cases, graft excision with extra-anatomic (obturator ileofemoral bypass) graft replacement in six cases, and excision alone in two cases. Of the 17 infections treated operatively and followed from 1 week to 18 months (median 5 months), eight (47%) showed no evidence of recurrence, six (35%) recurred, two (12%) caused early death, and one resulted in a thrombosed graft requiring extra-anatomic reconstruction. Of the nine infected grafts treated locally with muscle flaps, six showed recurrent infection from 3 weeks to 15 months and one thrombosed for a total local treatment failure rate of 78%. Only two grafts are free of infection at 4 and 5 months, respectively. Of the six incidences of infection treated with obturator bypass, four (66%) are free of infection and two resulted in patient death; both infections treated with excision alone were eradicated but resulted in a major lower extremity amputation. These data question the growing acceptance of debridement and local muscle flap coverage for the treatment of all prosthetic vascular graft infections confined to the groin, especially in patients who are diabetic or on systemic steroids.Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.     

Experimental treatment of vascular graft infection due to Staphylococcus epidermidis by in situ replacement with a rifampin-bonded polyester graft

In situ prosthetic graft replacement (ISPGR) of an infected prosthesis raises the risk of recurrent infection in the new graft, especially in cases involving drug-resistant microorganisms. The purpose of this animal study was to evaluate in situ replacement of a vascular graft infected by a highly rifampin-resistant strain of Staphylococcus epidermidis with the use of a rifampin-bonded polyester graft. Antibiotic bonding was obtained by soaking grafts in a high dose of rifampin solution (60 mg/mL). The infrarenal abdominal aorta of 20 dogs was replaced using a polyester prosthesis infected with a highly rifampin-resistant strain of Staphylococcus epidermidis. One week later, the 18 surviving animals were randomized into three groups. Group I (n = 6) did not undergo reoperation. Group II (n = 6) underwent ISPGR using a rifampin-bonded prosthesis. Group III (n = 6) underwent ISPGR using an untreated prosthesis. All surviving animals were killed 28 days after the first procedure. Infectious signs were noted and bacteriological study was carried out on explanted prostheses and various tissue samples. The findings of this experimental study show that soaking a polyester prosthesis in a high-dose rifampin solution can prevent reinfection after in situ replacement of a prosthesis infected by a highly rifampin-resistant Staphylococcus epidermidis.     

Aortic sepsis: is there a role for in situ graft reconstruction?

Conventional extraanatomic reconstruction for aortic sepsis is associated with a significant risk of operative death, as well as frequent late complications. We evaluated in situ aortic grafting in the treatment of primary or graft-related aortic infection. Eleven selected patients underwent in situ aortic graft reconstruction in the setting of mycotic aneurysm (n = 5), secondarily infected aortic aneurysm (n = 1), primary aortoenteric fistula (n = 1), and secondary aortoenteric fistula (n = 4). All patients survived: follow-up from 10 to 130 months reveals no evidence for graft thrombosis, pseudoaneurysm, new or recurrent aortoenteric fistula, or subsequent aortic operations in any patient. A literature review produced 110 cases of aortic sepsis managed by in situ aortic reconstruction during the last decade. Thirty-two patients (29%) either died in the operative period or suffered a lethal late complication associated with their aortic reconstruction. This mortality rate declined to 21% if patients undergoing incomplete removal of a contaminated graft were excluded, and to 19% with the addition of our 11 patients. Both our experience and that described in the literature suggest that, in properly-selected patients, in situ aortic graft replacement may be a rational treatment option for localized or circumscribed aortic sepsis.     

Mycotic abdominal aortic aneurysm induced by immunotherapy with bacille Calmette-Guérin vaccine for malignancy

Successful surgical treatment of a mycotic abdominal aortic aneurysm infected with Mycobacterium bovis is described. The infecting organism can be traced to an intraneoplastic injection of bacille Calmette-Guérin (BCG) vaccine into a cutaneous malignant melanoma nodule 14 months before aneurysm detection (17 months before operation). Treatment consisted of aneurysm excision, in situ prosthetic graft placement, and antituberculous medications. This patient represents the first reported case of BCG-induced mycotic aortic aneurysm.     

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.     

Mycotic aneurysms of the thoracic and abdominal aorta and iliac arteries: experience with anatomic and extra-anatomic repair in 33 cases

OBJECTIVE: A mycotic aneurysm of the aorta and adjacent arteries is a dreadful condition, threatening life, organs, and limbs. With regard to the aortic segment involved, repair by either in situ replacement or extra-anatomic reconstruction can be quite challenging. Even when surgery has been successful, the prognosis is described as very poor because of the weakened health status of the patient who has developed this type of aneurysm. The aim of our study was to find out whether any progress could be achieved in a single center over a long time period (18 years) through use of surgical techniques and antiseptic adjuncts. MATERIAL AND METHODS: From January 1983 to December 1999, a total of 2520 patients with aneurysms of the thoracic and abdominal aorta and iliac arteries underwent surgery for aortic or iliac replacement at our institution. During that period, 33 (1.31%) of these patients (mean age, 64.3 years) were treated for mycotic aneurysms of the lower descending and thoracoabdominal (n = 13), suprarenal (n = 4), and infrarenal (n = 10) aorta and iliac arteries (n = 6). Twenty (61%) of these 33 patients had histories of various septic diseases; in the other 13 (39%), the etiology remained uncertain. Preoperative signs of infection, such as leukocytosis and elevated C-reactive protein, were found in 79% of the patients, and fever was apparent in 48%; 76% of the patients complained of pain. At the time of surgery, eight (24%) mycotic aneurysms were already ruptured, and 20 (61%) had penetrated into the periaortic tissues, forming a contained rupture. Five (15%) aneurysms were completely intact. The predominant microorganisms found in the aneurysm sac were Staphylococcus aureus and Salmonella species. Careful debridement of all infected tissue was essential. In the infrarenal aortic and iliac vascular bed, in situ reconstruction was performed only in cases of anticipated "low-grade" infection. Alternative revascularization with extra-anatomic procedures (axillobifemoral or femorofemoral crossover bypass graft) was carried out in eight of 16 cases. All four suprarenal and all 13 mycotic aneurysms of the thoracoabdominal aortic segment were repaired in situ. Antibiotics were administered perioperatively, and all patients were subsequently treated with long-term antibiotics. RESULTS: In-hospital mortality was 36% (n = 12). Because of the smallness and heterogeneity of the sample, we could not demonstrate significant evidence for any influence of aneurysm location or type of reconstruction on patients' outcome. However, survival was clearly influenced by the status of rupture. During long-term follow-up (mean, 30 months; range, 1-139 months), 10 patients (48%) died-one (4.8%) probably as a consequence of the mycotic aneurysm, the others for unrelated reasons. Eleven patients (52%) are alive and well today, with no signs of persistent or recurrent infection. CONCLUSIONS: A mycotic aneurysm of the aortic iliac region remains a life-threatening condition, especially if the aneurysm has already ruptured by the time of surgery. Although the content of the aneurysm sac is considered septic, as was proved by positive cultures in 85% of our patients, in situ reconstruction is feasible and, surprisingly, was not more closely related to higher morbidity and mortality in our series than ligation and extra-anatomic reconstruction, although most of the aneurysms repaired in situ were located at the suprarenal and thoracoabdominal aorta. We assume that our operative mortality rate of 36%, which relates to a rupture rate of 85%, could be substantially lowered if the diagnosis of mycotic aneurysm were established before rupture.     

In situ replacement of infected aortic grafts with rifampicin-bonded prostheses: the Leicester experience (1992 to 1998)

PURPOSE: Prosthetic graft infection after aortic aneurysm surgery is a life-threatening complication. Treatment options include total graft excision and extra-anatomic bypass grafting or in situ replacement of the graft. The latter option is gaining increasing popularity, but the long-term outcome remains uncertain, particularly in light of the increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA). We performed a prospective nonrandomized study to assess the outcome after graft excision and in situ replacement with a rifampicin-bonded prosthesis for the treatment of major aortic graft infection. METHODS: In a 6-year period from January 1992 to December 1997, 11 patients (eight men, three women) with major aortic graft infection underwent total graft excision and in situ replacement with a rifampicin-bonded prosthesis. The median age of the patients was 66 years (range, 49 to 78 years). Four patients had a hemorrhage from an aortoenteric fistula, three had a retroperitoneal abscess, two had graft occlusion, one had a perigraft collection shown by means of computed tomography, and one had a ruptured suprarenal false aneurysm. Organisms were cultured from 10 patients. RESULTS: MRSA was isolated in two patients, both of whom had originally undergone repair of a ruptured abdominal aortic aneurysm. Two patients died (18.2%) within 30 days, and three patients (27.6%) had nonfatal complications (peritoneal candidiasis, transient renal impairment, and profound anorexia). Two patients died late in the follow-up period. Seven patients remain alive and clinically free of infection. CONCLUSION: The long-term results after total graft excision and in situ replacement with a rifampicin-bonded prosthesis appear to be favorable. However, MRSA aortic graft infection appears to be associated with a poor prognosis.     

Infection of vascular prostheses caused by bacterial biofilms

A canine model was developed to study the efficacy of graft replacement as treatment for vascular prosthesis infections from Staphylococcus epidermidis. Infrarenal aortic graft infections were established in 18 dogs by implantation of Dacron prostheses colonized in vitro with a slime-producing strain of S. epidermidis to form an adherent bacteria-laden biofilm (5 X 10(6) colony-forming units/cm2 graft). Study animals developed a graft infection with anatomic and microbiologic characteristics typical of late prosthetic graft infections in humans (sterile perigraft exudate, absent graft incorporation, and normal serum leukocyte count and sedimentation rate). The S. epidermidis study strain was isolated from 14 of 18 explanted grafts (78%) by mechanical disruption of the graft surface biofilm and culture in broth media. Four dogs with sterile graft cultures had histologic evidence of bacterial infection. The established prosthetic surface biofilm infection was treated by graft excision, parenteral cefazolin, and graft replacement with a Dacron or polytetrafluoroethylene (PTFE) vascular prosthesis. One month after graft replacement, no PTFE graft had signs of infection, but perigraft exudate and inflammation involved three of nine Dacron grafts (33%). The study strain was recovered from four of nine PTFE grafts (44%) and two of nine Dacron (22%) replacement grafts (p greater than 0.05). Prosthetic replacement of Dacron prostheses infected by S. epidermidis as a bacteria-laden surface biofilm can result in early graft healing, but persistent colonization of one third of replacement grafts signify that recurrent clinical infection remains a risk.     

Surgical treatment for primary infected aneurysm of the descending thoracic aorta,abdominal aorta,and iliac arteries

OBJECTIVE AND METHOD: In this retrospective review, we report the surgical results of infected aortic aneurysms treated at a single center over 5 years. RESULTS: From October 1996 to October 2001, 19 patients with infected aortic aneurysm were treated with surgery, nine with suprarenal infections (four proximal descending thoracic aortic aneurysms, two distal descending thoracic aortic aneurysms, and three suprarenal abdominal aortic aneurysms) and 10 with infrarenal infections (eight infrarenal abdominal aortic aneurysms and two iliac artery aneurysms). All had a positive blood or tissue culture; 89% were febrile, 89% had leukocytosis, and 32% were hemodynamically unstable. The most common responsible pathogens were Salmonella organisms (74%) followed by Streptococcus species (11%). Nine of 10 infrarenal infections were caused by Salmonella organisms. Both infrarenal and suprarenal infections were treated with wide débridement of infected aorta, in situ prosthetic graft or patch repair, and prolonged intravenous antibiotics. Hospital survival rate was 95%: 100% for infrarenal and 89% for suprarenal infections. There was no perioperative intestinal ischemia or perioperative limb loss. Acute renal failure occurred in two patients with suprarenal infection. Late deaths have occurred in three patients with one early graft infection (5%) resulting in the only one in-hospital death at 4 months. Sixteen patients remain alive at mean follow-up of 17.8 months (range, 4-47 months). There have been no late aortic or graft infections. During the same period, there were five unoperated patients, four of whom died of shock during hospitalization. CONCLUSIONS: Infected aortic aneurysm is common in Taiwan, and Salmonella species were the most common responsible microorganisms. With surgical intervention and prolonged intravenous antibiotics, in situ graft replacement provided a good outcome. The incidence of prosthetic graft infection was low, even in patients with infections due to Salmonella species and with in situ graft replacement.     

Experience with pyoktanin lavage for mediastinitis and prosthetic graft infection following thoracic aortic surgery

Pyoktanin, a triphenylmethane dye, is known to have a potent bactericidal activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). We used pyoktanin for irrigating wounds in 2 cases of mediastinitis and prosthetic graft infection following thoracic aortic surgery. Case 1 is mediastinitis and prosthetic graft infection due to Staphylococcus epidermidis following Cabrol procedure. After irrigating the anterior mediastinum with 0.1% pyoktanin solution twice a day for 8 days, omental transposition was performed, which let to cure of the infection. Case 2 is mediastinitis due to methicillin-resistant Staphylococcus epidermidis following ascending aortic and aortic arch replacement for acute type A aortic dissection. After irrigating the wound with 0.1% pyoktanin solution twice a day for 14 days, the wound was closed primarily, which resulted in cure of the infection of the wound. Using pyoktanin at low concentrations for irrigating wound for a short period of time is considered permissible and effective for mediastinitis and prosthetic graft infection due to Gram-positive bacteria including MRSA.     

Probable zoonotic aortitis due to group C streptococcal infection

Human infections due to group C streptococcus (SGC) are unusual. Among them, vascular compromise, especially aortic involvement, is extremely rare. A case of microbial aortitis with aneurysm formation, likely secondary to a SGC soft tissue infection, in a 61-year-old patient who was caring for a purulent leg wound of his horse, is presented. He was successfully treated with antibiotics and in situ aortic replacement with a prosthetic graft and an omental wrap. He remains well almost 2 years after surgical intervention. Aortic infection caused by SGC is a rare condition that can be successfully treated with in situ prosthetic graft replacement.     

Cardiac reoperation in a patient with osteogenesis imperfecta: a case report.

A case of a 40-year-old man with dehiscence of the prosthetic aortic valve and recurrence of mycotic aneurysm of the left ventricular outflow tract with osteogenesis imperfecta is presented. He had an operation of aortic valve replacement and direct closure of the mycotic aneurysm for infective endocarditis twenty-one months ago. We performed reoperation of prosthetic aortic valve, patch closure of the mycotic aneurysm and graft replacement of the ascending aorta. He was complicated with multiple fractures of bilateral scapla and dislocation of left shoulder one postoperative day. Fortunately, cardiac reoperation was performed successfully in this patient despite anticipated difficulties with tissue friability with osteogenesis imperfecta.