A meta-analysis of outcomes of in-situ reconstruction after total or partial removal of infected abdominal aortic graft

INTRODUCTION

There is currently a lack of evidence for the relative effectiveness of partial resection (PR) and total resection (TR) before managing abdominal aortic graft infection (AGI). Most authorities agree that TR is mandatory for intracavitary AGI in patients with favorable conditions but there is an increasing number of patients with severe comorbidities for whom this approach is not suitable, resulting in a prohibitive mortality rate. The purpose of this study was to determine the most appropriate indication for TR or PR.

EVIDENCE ACQUISITION

A meta-analysis was conducted on the rates of early/late mortality, amputations and reinfection. A meta-regression was performed with eight variables: patient age, male prevalence, presence of virulent or nonvirulent organisms, urgency, omentoplasty and follow-up.

EVIDENCE SYNTHESIS

Twenty-one studies and 1052 patients were included. For TR and PR, the rates of early mortality and reinfection were 16.8% and 10.5%, 11% and 27%, respectively. For TR urgency and male gender were associated with increased rate of early mortality and male gender, PDF and virulent organisms were associated with increased risk of reinfection. For PR no statistical correlation was analyzable except for PDF with increased risk of reinfection.

CONCLUSIONS

Early mortality rates are higher for TR and reinfection rates are higher for PR. For TR early mortality increases in urgent cases and it is suggested that alternative option must be discussed, reinfection decreases in the presence of nonvirulent organisms and TR seems optimal. For TR and PR reinfection increases in presence of PDF and alternative technique may be more appropriate.

[Treatment of radiation-induced iliofemoral arterial complications with groin radionecrosis]

Long-term iliofemoral complications induced by radiation include vascular (arterial and venous) lesions, nervous lesions and soft tissue loss that can be cutaneous and subcutaneous and potentially lead to radionecrosis with vessel exposure. We present five cases of groin radionecrosis. There were three men and two women (age 30-73 years). Radiotherapy had been delivered 15 years earlier in three cases, and 2 years earlier in two cases. Symptoms were intermittent claudication (n=1), critical ischemia (n=1), and septic hemorrhage (n=1). Two patients had no vascular symptoms. Four patients underwent scheduled surgery after complete cardiac and cardiovascular evaluation with duplex-Doppler, CT scan and/or intra-arterial angiography. One woman underwent emergency surgery after septic hemorrhage of a previous in situ femoral revascularization fashioned 2 months earlier. Revascularization was achieved with trans-iliac (n=3), trans-muscular (n=1, and in situ (n=1) iliofemoral bypass. A retroperitoneal approach with section of large muscles was used. In three cases, a trans-iliac route was used by perforating the iliac wing with a 8-mm PTFE graft. Proximal anastomosis was done on the abdominal aorta (n=1) and the homolateral common iliac artery (n=2). Distal anastomosis was done on the distal profunda artery and popliteal artery (n=1) and on the distal femoral superficial artery (n=2). In two cases, an iliofemoral bypass was done with a 7-mm PTFE vascular graft. The proximal anastomosis was done on the proximal external iliac artery and the distal anastomosis on the proximal superficial femoral artery. A plastic procedure was performed in four cases. Three patients had a homolateral (n=1) or controlateral (n=2) rectus abdominis flap. In one case, plastic coverage was done with an antebrachial flap (Chinese flap), which has been released at 6 weeks. One patient had post-radiotherapy iliofemoral vascular disease, but there was no vascular exposure, and no plastic coverage was necessary. The postoperative course was uneventful in four cases. The patient treated with an in situ bypass developed septic hemorrhage at day 10, requiring revision. The patient died of multiple organ system failure, with a patent graft and a viable flap. The other four patients had no early or late complications. These patients have been followed annually for clinical examinations and duplex scans, and angio-scans. One patient died of ischemic heart disease. The three other patients are alive with a patent bypass with 11, 8 and 3 years follow-up. One patient had a late occlusion of the bypass treated by thrombectomy after 7 and 10 years. In conclusion, patients with femoral radionecrosis can be treated by an extra-anatomic bypass, with plastic coverage. The trans-iliac is a relatively simple and safe procedure.

Case Study: Chronic Femoropopliteal Prosthetic Graft Infection With Exposed Graft

One of the most feared complications following vascular reconstruction is infection due to the attendant risks of limb loss, sepsis, or death. The reported incidence of infection following infrainguinal prosthetic graft infection is 2.5% with associated mortality rates and amputation rates of 18% and 41%, respectively. There are several options in treating infected prosthetic infrainguinal bypass grafts. Some authors have advocated complete removal of the infected graft with concomitant in situ revascularization using autogenous tissue or extra-anatomic bypass using either autogenous or prosthetic material, depending upon the clinical circumstances. Other authors have advocated attempting graft preservation to decrease the risk of amputation. Infected, thrombosed grafts are generally treated with graft excision alone with care taken to preserve collateral flow. The treatment options may also be influenced by the type of infection, as infections caused by gram-negative bacteria are thought to be more virulent than those associated with gram-positive bacteria. We recently treated a patient with an 18-month history of an exposed prosthetic graft in the groin, which was infected by Proteus mirabilis. Despite the extended period of graft exposure and despite gram-negative bacteria being the causative organism, the patient reported only intermittent drainage of pus from the groin. The management of this unusual infection forms the basis of this report.

Endovascular native vessel recanalization to maintain limb perfusion after infected prosthetic vascular graft excision

Prosthetic vascular graft infection is an uncommon yet serious condition. Traditional management has included debridement, excision of the infected graft, and revascularization as needed. We report on two cases in which limb viability was maintained by using endovascular native vessel recanalization after excision of infected prosthetic grafts. This approach was successful in maintaining adequate limb perfusion in both cases. Endovascular native vessel recanalization should be considered as an option to maintain limb viability after excision of infected prosthetic vascular grafts, especially when autogenous conduit is lacking or limitation of the extent of surgery is desirable.

In situ revascularization with silver-coated polyester grafts to treat aortic infection: early and midterm results

PURPOSE

In this prospective study we analyzed the immediate and midterm outcome in patients with abdominal aorta infection (mycotic aneurysm, prosthetic graft infection) managed by excision of the aneurysm or the infected vascular prosthesis and in situ replacement with a silver-coated polyester prosthesis.

METHODS

From January 2000 to December 2001, 27 consecutive patients (25 men, 2 women; mean age, 69 years) with an abdominal aortic infection were entered in the study at seven participating centers. Infection was managed with either total (n = 18) or partial (n = 6) excision of the infected aorta and in situ reconstruction with an InterGard Silver (IGS) collagen and silver acetate-coated polyester graft. Assessment of outcome was based on survival, limb salvage, persistent or recurrent infection, and prosthetic graft patency.

RESULTS

Twenty-four patients had prosthetic graft infections, graft-duodenal fistula in 12 and graft-colonic fistula in 1; and the remaining 3 patients had primary aortic infections. Most organisms cultured were of low virulence. The IGS prosthesis was placed emergently in 11 patients (41%). Mean follow-up was 16.5 months (range, 3-30 months). Perioperative mortality was 15%; all four patients who died had a prosthetic graft infection. Actuarial survival at 24 months was 85%. No major amputations were noted in this series. Recurrent infection developed in only one patient (3.7%). Postoperative antibiotic therapy did not exceed 3 months, except in one patient. No incidence of prosthetic graft thrombosis was noted during follow-up.

CONCLUSION

Preliminary results in this small series demonstrate favorable outcome with IGS grafts used to treat infection in abdominal aortic grafts and aneurysms caused by organisms with low virulence. Larger series and longer follow-up will be required to compare the role of IGS grafts with other treatment options in infected fields.

Exposure of plasma proteins on Dacron and ePTFE vascular graft material in a perfusion model

OBJECTIVES

to compare the exposure of plasma proteins adsorbed onto three vascular graft materials (polytetrafluoroethylene ePTFE and two modifications of polyethyleneterephthalate Dacron).

METHODS

surface exposure of fibronectin, vitronectin, thrombospondin, antithrombin III, IgG, high molecular-weight kininogen, fibrinogen, albumin and plasminogen was studied by incubation with radiolabelled antibodies in a perfusion model. Perfusion times with human plasma were 1, 4, 24 and 48 hours.

RESULTS

all proteins could be detected at 1, 4, 24 and 48 hours after the start of perfusion. Overall, the least amount of proteins adsorbed onto ePTFE.

CONCLUSIONS

the low adsorption of proteins onto ePTFE may be one of the reasons for the lower incidence of infections reported with this material.

Infection in the ischemic lower extremity

Infections in the lower extremity of the patient with ischemia can cover a broad spectrum of different diseases. An understanding of the particular pathophysiologic circumstances in the ischemic extremity can be of great value in understanding the natural history of the disease and the potential complications that may occur. Optimizing blood flow to the extremity by using revascularization techniques is important for any patient with an ischemic lower extremity complicated by infection or ulceration. Infections in the ischemic lower extremity require local débridement and systemic antibiotics. For severe infections, such as necrotizing fasciitis or the fetid foot, more extensive local débridement and even amputation may be required. Fundamentals of managing prosthetic graft infection require removing the infected prosthesis, local wound débridement, and systemic antibiotics while attempting to preserve viability of the lower extremity using autogenous graft reconstruction.

Bacterial and clinical criteria relating to the outcome of patients undergoing in situ replacement of infected abdominal aortic grafts

OBJECTIVES

In a retrospective non-randomised study we assessed the outcome after in situ replacement of infected knitted Dacron abdominal aortic grafts in patients without septicaemia or retroperitoneal abscesses. We also assessed whether the specific bacterial infection influenced outcome.

MATERIALS AND METHODS

Over the 5 years studied, 18 patients (9 with perigraft infection and 9 with aortoenteric erosion) underwent in situ replacement of aortofemoral grafts. All patients were haemodynamically stable, none required emergency treatment. Preoperative assessment included CT, MRI, leukocyte-labelled scintigraphy, and bacterial cultures whenever possible. Infected grafts were totally excised and replaced in situ with standard PTFE prostheses. Bacterial diagnosis included intraoperative Gram-staining and postoperative graft cultures. None of the patients had retroperitoneal collections or proximal anastomotic dehiscence. All patients had 6 week intravenous antibiotic therapy.

RESULTS

One patient died of myocardial infarction, and another of haemorrhagic shock from proximal anastomotic dehiscence, accounting for a graft-related mortality of 6%. Dehiscence resulted from a polymicrobial infection. Mean 37 month surveillance showed no amputations and no graft-related infections.

CONCLUSIONS

In clinically and bacteriologically selected patients, total in situ replacement of infected abdominal aortic grafts offers an excellent outcome.

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 situ replacement 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.

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 grafted 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.

The aortic polytetrafluoroethylene graft: further experience

OBJECTIVES

We analysed our results with the use of aortic polytetrafluoroethylene PTFE grafts over the last 7.5 years. A historical comparison was also made between the results with non-stretch PTFE (NS-PTFE) (1987-91) and stretch PTFE (S-PTFE) grafts (1991-94).

MATERIALS

244 infrarenal aortic replacements or bypasses with PTFE grafts were performed at the University of Iowa Hospitals and Clinics from January 1987 to June 1994. Infrarenal aortic replacement was indicated for aortic aneurysmal disease in 192 patients (elective 151, symptomatic 20, ruptured 21) and bypass for aorto-iliac occlusive disease in 52 patients (disabling claudication 28, limb salvage 24). Patients ranged in age from 37 to 93 years (mean 68 years). There were 161 males and 83 females. Medical risk factors included hypertension (55%), coronary artery disease (31%), COPD (23%), diabetes mellitus (12%) chronic renal failure (9%), and smoking (61%). Aortic replacement or bypass was done with a NS-PTFE graft in 108 patients (44%) and a S-PTFE graft in 136 patients (56%). Postoperative ultrasound (US) scans and/or CT-studies were available in 40 patients with NS-PTFE and 26 patients with S-PTFE grafts.

MAIN RESULTS

The 30 day operative mortality was: elective AAA patients (1.3%), symptomatic AAA patients (10%), ruptured AAA patients (48%), limb salvage patients (4.1%) and disabling claudication patients (0%). Graft related complications included five graft limb thromboses (4 NS-PTFE, 1 S-PTFE). Two thromboses occurred perioperatively and the three others at 24, 28 and 30 months postoperatively. Two other graft related complications included a mixed pseudomonas and streptococcus groin infection with a culture negative perigraft fluid collection occurring 3 weeks following surgery (NS-PTFE), and distal aortic anastomotic suture line bleed on the first postoperative day following replacement of a ruptured AAA with a S-PTFE graft. Based on US and/or CT imaging studies, the mean internal diameters of the bodies of 40 NS-PTFE and 26 S-PTFE grafts were 11% and 10% greater than the manufacturer's specified sizes at a mean follow-up duration of 36 and 10 months respectively.

CONCLUSIONS

These data reveal that a PTFE graft performs satisfactorily in the aortic position with minimal adverse clinical sequence over a 7.5 year period. Continued long term follow up data will determine the ultimate suitability of aortic PTFE grafts.

Surgical management of infrainguinal arterial prosthetic graft infections: review of a thirty-five-year experience

PURPOSE

The purpose was to determine the early and late mortality and morbidity rates associated with infrainguinal arterial prosthetic graft infection (IAPGI) and to identify optimal methods of management.

METHODS

The study included 53 men and 14 women (mean age, 61 years) in whom a total of 68 IAPGIs developed in the years 1959 to 1993. IAPGI involved 58 femoropopliteal grafts (85%), six femorodistal grafts (9%), and four other grafts or synthetic patches (6%). Graft material was dacron in 36 (53%), polytetrafluoroethylene in 28 (41%), and human umbilical vein in four (6%). Sixteen IAPGIs (24%) involved limbs that had required amputations before IAPGI was diagnosed. Twenty-six (38%) of the 68 grafts were thrombosed, and 14 (88%) of the 16 amputees had occluded grafts.

RESULTS

Staphylococcal organisms were isolated from 34 (58%) of the 59 IAPGIs for which culture data were available. The median intervals until IAPGI was diagnosed were 3 months after implantation and 1 month after the last procedure involving the original graft. Initial management consisted of local measures only in 13 (19%), partial removal or in situ graft replacement in 15 (22%), and total graft excision in 40 (59%). Total excision was performed in 15 (94%) of the 16 patients with prior amputations and in only 25 (48%) of the 52 intact limbs. The overall postoperative mortality rate was 18%; seven (58%) of the 12 early deaths were related to sepsis, and all 12 occurred within the group of 51 patients (24%) for whom limb salvage was still being attempted (p = 0.056). IAPGI ultimately led to amputations in 21 (40%) of 52 intact limbs within the first year. Twenty-three (82%) of the 28 IAPGIs managed with incomplete graft removal required subsequent operations for continued sepsis, compared with five (13%) of the 40 treated with complete excision (p < 0.001). The cumulative 5-year survival rate (77%) for 53 patients who survived operation was less than that (89%) for the normal, age-matched U.S. male population.

CONCLUSIONS

IAPGI is associated with substantial early mortality and amputation rates. Complete excision of infected graft material results in a significant reduction in the incidence of recurrent sepsis.

Histopathological characteristics of explanted human prosthetic arterial grafts: implications for the prevention and management of graft infection

OBJECTIVE

to study the histopathological characteristics of prosthetic vascular graft infection.

DESIGN

prospective clinical study over 2 years.

SETTING

University Hospital.

MATERIALS

36 infected and 29 uninfected (control) chronically implanted vascular prostheses (half aortic) were removed and 352 sections prepared.

CHIEF OUTCOME MEASURES

light microscopy (multiple stains), scanning electron microscopy (SEM), and multiple culture techniques to identify characteristics of healing, infection, and microorganisms.

MAIN RESULTS

Acute inflammation (AI) (neurophils, granulocytes and necrosis) were seen in 75% of infected grafts, were most prominent in the perigraft tissue and rarely seen on the luminal surface. These were usually well localised, leaving the remainder of a graft well incorporated with no signs of infection. In 25% of clinically infected, culture-positive grafts there was no significant acute inflammation. Chronic inflammation (CI) (macrophages, lymphocytes, monocytes, giant cells) was seen in 70% of both control and infected grafts. In 50% of both groups a significant lymphocytic population was composed exclusively of T-lymphocytes suggesting a true host vs graft response. Unincorporated chronically implanted grafts (> 1 yr) were seen with equal frequency in the two groups although more diffusely unincorporated grafts were infected. Microorganisms were cultured from 23 infected grafts (64%) and were, at microscopy, mostly found outside the graft and nerves on the luminal side.

CONCLUSIONS

This data cast doubt on criteria commonly used to distinguish graft infections and host vs. graft reactions from normal graft healing. Acute and chronic inflammation are not predictive of infection.

The fate of the aortofemoral graft

OBJECTIVE

To determine the incidence and cause for reoperation following aortofemoral bypass surgery.

DESIGN

This paper describes the results of all aortofemoral grafts performed in the years 1978-1991, 251 of these patients underwent an aortobifemoral graft (ABF) whilst the remaining 50 had an aortounifemoral graft (AUF).

RESULTS

The aortofemoral bypass was the only operation performed in fewer than half of the patients. Sixteen per cent of ABF and 50% of the AUF patients had surgery before the index operation. Subsequently 33% of the ABF patients and 60% of the AUF group had one or more additional vascular procedures. Graft infections and false aneurysms continued to present in about 1% patients per year at least up to 10 years following surgery. The 5 year actuarial survival was 73% in the ABF group and 38% in the AUF patients. The primary patency at 5 years was 85% in the ABF patients and 81% in the AUF group. Amputation was performed in 6% of the ABF patients and in 20% of the AUF patients.

CONCLUSIONS

The frequent need for later surgery (1:3 for the ABF patients) should be considered in the decision to undertake the initial aortofemoral operation when the patient presents with intermittent claudication.