Vascular prosthetic graft infection: epidemiology, bacteriology, pathogenesis and treatment.

UNLABELLED: Vascular prosthetic graft infection remains a major surgical challenge. Prevention of risk factors and antibiotic therapy can reduced but not eradicate it. Management of infected vascular grafts depends on several factors, including the location of the infected prosthesis, the extent of infection, and the underlying micro-organism. Classic treatment consists of extra-anatomic bypass grafting. The disappointing results due to the high mortality and amputation rate have kindled interest in alternative approaches, such as in situ reconstruction with antibiotic-bonded prostheses, autogenous veins or arterial allografts. PURPOSE: We focused on the treatment of aortic graft infection by means of both fresh and cryopreserved arterial allograft. Here, the experience of the Italian Collaborative Vascular Homograft Group is reported. METHODS: Between March 1994 and December 2000 seventy-nine patients with aortic graft infection were treated. The results of 68 patients are analysed. Eleven patients were treated with fresh, and 57 with cryopreserved homograft. Emergency surgical procedures were performed in 12 patients (17%). Aortoenteric fistula was diagnosed in 22 patients. The mean interval between the first procedure and the insertion of a homograft for patients with infected aortic graft was 3 years (range 1-15). The mean duration of follow-up was 30 months (range 1-68). Clinical and duplex scanning evaluation were routinely performed. Computer tomography (CT), magnetic resonance (MR), or arteriography were performed on the basis of duplex scanning results. RESULTS: The analysis was performed on 68 cases for which there were sufficient reliable data. Eleven deaths occurred during the early postoperative period (30 days), a mortality rate of 16%. There were also seventeen late deaths, a mortality rate of 25%. Eleven patients had graft occlusion; six cases were successfully treated with thrombectomy. In three cases leg amputation was necessary. The results of fresh and cryopreserved homografts were compared. No significant differences of early postoperative mortality, late mortality, homograft-related mortality, graft failure were observed. The presence of aortoenteric fistula is a negative predicting factor of perioperative early mortality, which causes a rapid decline in the survival curve. Thirty-six months after the surgery the actuarial survival of the patients was 57% and the actuarial patency of the allograft was 41%. CONCLUSION: No significant difference in terms of clinical outcome was observed when using fresh, rather than cryopreserved homografts. The only factor that significantly influenced the survival rate appeared to be the aorto-enteric fistula.

Fresh and cryopreserved arterial homografts in the treatment of prosthetic graft infections: experience of the Italian Collaborative Vascular Homograft Group.

Following the experience of cardiac surgeons with homografts in the treatment of infective aortic valve endocarditis, cardiovascular surgeons have investigated in situ revascularization by means of homografts in the management of vascular prosthetic graft infections. Preliminary results are encouraging, but their late fate in long-term follow-up and the influence of preservation techniques are still under investigation. This article reports the experience of the Italian Collaborative Vascular Homograft Group, with the use of fresh and cryopreserved arterial homografts for the treatment of prosthetic graft infections. Between March 1994 and December 1996, 44 patients with prosthetic graft infection were treated with homografts (13 preserved at 4 degrees C, 31 cryopreserved). The mean age of the patients was 65 years. Emergency surgical procedures were performed in eight patients (18%). Sepsis was diagnosed in 11 patients, aortoenteric fistula in 13, and false aneurysms in 10. Staphylococcus was the main cause of infection. The types of vascular reconstruction with homograft were: 32 aortobifemoral, 3 aortoaortic, 2 iliofemoral, 4 peripheral, and 3 axillobifemoral. Human lymphocyte antigen (HLA) and antibody (ABO) blood group system compatibility between donors and recipients was not respected. The mean duration of follow-up was 15 months (range 1-33). Clinical and duplex scanning evaluations were routinely performed. Computed tomography (CT) or magnetic resonance (MR) scanning or arteriography were performed on the basis of duplex scanning results. There were six deaths during the early postoperative period (30 days) with a mortality rate of 13.6%. During the follow-up there were five late deaths with a mortality rate of 11.4%. Eight patients had graft occlusion. Three cases were successfully treated with thrombectomy. Two cases were successfully treated with femoropopliteal bypass with autologous vein. In three cases leg amputation was necessary. The results of fresh and cryopreserved homograft were compared. No significative differences of early postoperative mortality, late mortality, homograft related mortality, and graft occlusion were observed. We have evaluated the actuarial survival of the patients and the actuarial patency of the homografts on the aortoiliac reconstructions. Twelve months after the surgery the actuarial survival of the patients was 73% and the actuarial patency of the homografts was 56%. In our preliminary experience, we have not observed any significant difference in terms of clinical outcome by using fresh rather than cryopreserved homografts. In the near future it will be our policy to employ only cryopreserved homografts. Moreover, we will extend vessel harvesting to nonheart-beating donors, thus maximizing retrieval. The aforementioned solutions will supply the best graft availability to obtain dimensional and ABO compatibility between donors and recipients.

Surgical treatment of popliteal artery aneurysm. A 20 year experience.

OBJECTIVES: A retrospective study to evaluate the treatment, long term follow-up and factors affecting revascularization results particularly in regard to clinical presentation and prosthetic materials used after 20 years of experience. MATERIALS AND METHODS: Between 1974 and September 1995 there were 67 popliteal aneurysms in 58 patients. Three patients underwent a primary amputation because of irreversible ischaemia and 3 patients a surgical sympathectomy. Operative repair was performed in 61 cases: as an emergency in 9 (14.7%) limbs and as an elective procedure in 52 (85.3%) limbs. Graft replacement was performed employing polytetrafluoroethylene (PTFE) grafts in 34 (55.7%) cases 13 of which with Ringed PTFE, autogenous saphenous vein in 10 (16.4%) cases and Dacron in 17 (27.9%). RESULTS: The cumulative primary patency (CP) and limb salvage rate (LS) at 10 years were 75.1% and 83.3% respectively. We divided the patients into two groups: asymptomatic (Group I) and symptomatic with limb threatening ischemia (Group II). At 10 years the CP in Group I and II were 78.2% vs 67.2% respectively (p < 0.05 at 18 months) and the LS 87.4% vs 74.6% (p < 0.05). There was no statistical difference in terms of CP and LS rate between saphenous vein and PTFE. The use of PTFE grafts avoided harvesting of the long saphenous vein; this resulted in a significantly reduced operation time (135 +/- 18.6 vs 195 +/- 22.4 minutes, p < 0.001) and length of stay (7.4 vs 8.8 days, p < 0.02). CONCLUSIONS: We conclude that elective repair is indicated in all patients with popliteal aneurysm > or = 2 cm to avoid a critical ischemia with poorer results in terms of CP and LS. In the last 3 years our technique of choice is the exclusion of the aneurysm with a short PTFE bypass with good long-term of CP and LS rates.

[Epidemiology, natural history and indications for carotid thromboendarterectomy]. / Epidemiologia, storia naturale ed indicazioni alla tromboendoarteriectomia carotidea.

Stroke is the third most common cause of death in the occidental population and most important cause of disability. The average annual incidence of cerebral ischemia is increasing linked to population's mean age that is growing together with risk factors for cerebrovascular disease. There are many multicentre randomised trials (NASCET, ECST, Vet. Adm. SCT, CASANOVA, ACSV Adm. Study, ACAS, ACST) that identify surgical therapy as a prevention for stroke in symptomatic and asymptomatic patients. In discussing about all these studies it appears the necessity to follow the surgical guide-line proposed by multicentre trials in order to uniform indications for surgical or conservative therapy and to obtain data and results good enough to be effective in preventing really efficaciously stroke.

Role of bypass, endarterectomy, extra-anatomic bypass and endovascular surgery in unilateral iliac occlusive disease: a review of 1257 cases.

Some 1257 patients who had undergone revascularization procedures for unilateral iliac occlusions were reviewed retrospectively. A total of 824 patients were operated upon using conventional operations, 165 patients had femorofemoral bypass and 268 were treated using endovascular surgery techniques. Revascularization was performed through an extraperitoneal approach by means of iliac thromboendarterectomy (560) or iliac femoral bypass (264) if there was a total occlusion of either the common or external iliac artery (group 1). A femorofemoral crossover bypass was inserted when the operative risk was considered to be high (group 2). Endovascular procedures (percutaneous transluminal angioplasty 234, laser percutaneous transluminal angioplasty 11, stenting 22, atherectomy one) were used in recent years to treat stenoses or occlusions of 3 cm or less (group 3). The indications for operation were severe claudication in 79.7% in group 1 and 92.6% in group 3, whereas in group 2 66.7% of patients presented with symptoms of more advanced ischaemia. The immediate patency rate was 97.0% after extraperitoneal reconstructive surgery, 96.9% in the femorofemoral group and 92.1% in patients having an endovascular procedure. The operative mortality rate was 0.7, 4.2, and 0.3% for groups 1-3, respectively. The 5-year patency rate, analysed by the life-table method, was 77.9% in group 1, 75.3% in group 2 and 73.7% in group 3 (P = n.s., log rank test). The different revascularization techniques were chosen on the basis of the type of disease present and the patient's general condition. All procedures appeared to be effective when correctly selected.

[The role of iloprost in vascular surgery]. / Ruolo di iloprost nella chirurgia vascolare.

Use of prostanoids in vascular surgery is valuable in various conditions: intra and postoperatively, during limb salvage procedures, they are useful to lower peripheral resistances, and in patients with limited gangrene, when surgery is not feasible, they improve limb blood flow. After some years of subjective clinical evaluation, multicentric randomized clinical trials started; the aim was to quantify the real benefit derived from the use of prostanoids to the evolution of limb ischemia and to the improvement of results of surgical revascularization. We have not yet definitive results; preliminary data show a better immediate patency rate of femoro-distal bypass grafts and a critical reduction in long term limb amputations.

Intraoperative transluminal angioplasty of recurrent carotid stenosis.

A 61-year-old female presented with symptomatic recurrent left internal carotid stenosis. A method of intraoperative balloon dilatation under protective clamping of the common carotid artery is described.

Prediction of cerebral ischaemia using loco-regional anaesthesia.

The authors present their experience in cerebral monitoring during carotid surgery by surveillance of the clinical status of the patients. The operation was performed using loco-regional anaesthesia and employing a temporary shunt in those cases with cerebral ischaemic symptoms at clamping. In the 212 operations performed, no complication due to inadequate monitoring or complications related to coronary disease or respiratory insufficiency were observed.

In situ saphenous vein bypass for limb salvage.

A total of 130 infrapopliteal in situ saphenous vein bypasses were performed in 128 patients between January 1980 and June 1991. The indication for surgery was critical ischaemia with impending limb loss in 121 patients; seven suffered from severe claudication. The distal anastomosis was to the popliteal artery below the knee in 60 cases (46.2%) and in 70 (53.8%) to the tibioperoneal arteries. The results, in terms of secondary patency and limb salvage rates, of the first 68 procedures (1980-1985) and subsequent 62 (1986-June 1991) were compared. In the first period, a secondary patency rate of 42.6% and a limb salvage rate of 67.0% were obtained, compared with 71.3 and 80.8% respectively in the second. These differences are significant for patency (P < 0.005) and limb salvage (P < 0.01). These results show that the in situ technique can give acceptable results but a learning period with a high percentage of early failures is to be expected.

Thrombectomy for late graft limb occlusion: our experience in 182 consecutive cases.

Late occlusion of an aortofemoral bypass graft is usually caused by fibrointimal hyperplasia or progressive atherosclerosis. Several surgical approaches have been advocated in order to minimize the operative risk, to correct the impaired inflow and to provide a satisfactory outflow. In the last 16 years, in the Institute of Vascular Surgery and Angiology of the University of Milan, we have operated upon 182 consecutive thrombosed grafts. Inflow was restored by performing a graft limb thrombectomy using a Fogarty balloon catheter and simultaneously employing an endarterectomy ring stripper to dislodge tenaciously adherent fibrinous material and thrombotic plug. As the superficial femoral artery was generally occluded, usually a good outflow was achieved by profundaplasty in 101 cases (55.5%) or direct bypass (interposition graft), to a more distal segment of the profunda femoris artery in 55 cases (30.2%). Concomitant popliteal or tibial revascularization was done in the remaining 26 cases (14.3%) when pre-operative or intra-operative findings suggested an inadequate collateral network through the profunda femoris artery. Early re-occlusion, which occurred in 14 cases (7.6%), generally due to insufficient outflow, was corrected by additional intervention in 7 cases (3.8%), while 7 legs were amputated for extensive atherosclerotic disease. Six patients died giving a mortality rate of 3.3%. This low rate in a high risk population is probably related to our policy of operating under loco-regional anaesthesia. Long term results, with a patency rate of 62.0% at 3 years and 60.2% at 5 years (life table method), prove that this operation is a durable procedure for correction of graft limb thrombosis.

Femoral noninfected anastomotic aneurysms. A report of 56 cases.

Fifty-six femoral non infected anastomotic false aneurysms (FAAs) were observed in 49 patients admitted to the Institute of Vascular Surgery, University of Milan, from 1975 to 1988; in 6 patients they were bilateral. These aneurysms developed after primary revascularization procedures at a mean interval of 66 months (range 12 to 156 months); one recurred after reparative surgery. Forty-four FAAs (78.6%) were asymptomatic, whereas 3 (5.3%) were complicated by acute expansion and 9 (16.1%) by thrombosis. Host vessel degeneration was the cause of aneurysm formation in most cases. A history of hypertension was present in 30% of the patients. All anastomotic aneurysms were operated upon except for one small aneurysm that was asymptomatic. In 5 patients aneurysm resection was carried out on both sides. The surgical technique was endoaneurysmectomy in all the cases with insertion of an interposition graft in 48 cases, a fabric patch in 2 cases and prosthesis re-anastomosis in 5 cases. One case of peripheral embolization occurring in the early postoperative period was successfully treated and there was no operative mortality. In our opinion elective repair of these aneurysms should be recommended whenever possible because of their propensity to develop serious complications and the operative morbidity is low.

The role of regional nerve block anesthesia for carotid endarterectomy: an experimental comparison with previous series with the use of general anesthesia and barbiturates for cerebral protection.

A retrospective analysis was performed on a consecutive series of 60 cases divided into two groups given carotid endarterectomy (C.E.) for atherosclerotic disease. In the first group general anesthesia and barbiturate cerebral protection were employed; in group two, loco-regional anesthesia. Indications and risk factors were similar in the two groups; the surgical procedure was identical. The differences in the results are reported and factors contributing to cerebral protection or reduction in the risk of stroke are analyzed. The analysis indicates that loco-regional anesthesia for C.E. is a reliable method for detecting cerebral ischemia and guaranteeing cerebral protection by means of a temporary shunt when strictly necessary.

Semiclosed thromboendoarterectomy on femoro-popliteal tract revisited after a fourteen years experience on 595 cases.

In the seventies atherosclerotic femoropopliteal lesions were extensively treated by means of retrograde semiclosed thromboendarterectomy (FP-TEA) an analytic follow-up of cases, until 1980, induced the modification of the indications to FP-TEA. Currently the FP-TEA technique is only employed for patients at the 2nd Fontaine's stage with disabling claudication (generally less than 100 mt) with a good distal run-off (at least 2 tibial vessels patent). The report deals with a series of 595 cases operated in the period January 1971-December 1984. In 45% of cases FP-TEA was associated with a proximal revascularization. In an attempt to focus on the factors that may influence the outcome, the patients operated in 1976, 1980, 1984, were assessed and the results related to clinical stage, angiographic pattern and postoperative treatment.