Mycotic arterial aneurysm secondary to BCG intravesical instillation: A review

OBJECTIVE

Mycotic aortic aneurysm is a rare and life-threatening pathology. The first case of mycotic aneurysm induced by immunotherapy with bacille Calmette-Guérin for malignancy was published in 1988. The main objective of this review is to characterize this rare pathology.

MATERIALS AND METHODS

Since then, 60 cases of arterial aneurysm following intra vesical BCG instillation have been described in the literature. All cases have been included, and characteristics have been collected retrospectively, with simple statistical analyses of the cases.

RESULTS

We present a brief review from 1988 to 2022 enhancing the contemporary understanding of this arterial infection. Mycotic aneurysm secondary to BCG instillation has a poor prognosis, up to 50% complication and 15% mortality at 1 month, whether managed by open repair or endovascular means.

CONCLUSION

BCG mycotic aneurysm is an extremely serious condition, the diagnosis of which must be considered at an early stage in order to adapt diagnostic and therapeutic strategies.

A case of a 15-year evolution of a coral reef aortic lesion

We are reporting here the 15-year history of a patient affected by a chronic and evolutive coral reef aorta successfully treated by repeated revascularization.

Mycoplasma hominis wound infection after a vascular allograft

Cases of Mycoplasma hominis infections after allograft are rare. We report a case of M. hominis wound infection after a vascular allograft. The allograft was positive before having any contact with the recipient, and our investigation suggests that M. hominis may have been transmitted from the donor to the recipient. It is not clear, however, whether specific diagnosis of M. hominis should be performed on tissue before grafting in order to prevent such donor-to-host transmission.

Percutaneous Repair of Aortic Aneurysms: A Prospective Study of Suture-Mediated Closure Devices

PURPOSE

To evaluate prospectively the safety and efficacy of totally percutaneous placement of abdominal and thoracic aortic endografts using the Prostar XL suture-mediated closure system.

METHODS

From January 2002 to January 2005, we attempted to insert percutaneously all bifurcated abdominal aortic and thoracic endografts. Consecutive patients (25 men, four women), with mean age 74.9 years (range 44-84), underwent endovascular repair for 20 abdominal aortic aneurysms (AAA) and nine thoracic aortic aneurysms (repeat operation in one case). Endografts used included 21 Zenith (Cook), eight Talent (Medtronic), one AneuRx (Medtronic). For the <<pre-close>> technique, two Prostar XL 8F were used to close 22-24F access sites and one Prostar XL 10F to close 16F access sites.

RESULTS

Procedural success was achieved in 21/29 (72.4%) patients and in 39/47 access sites (83%). Closure of 22-24F access sites with tandem 8F Prostar devices was successful in 23/29 (79.3%) cases. Closure of 16F access sites with 10F Prostar device was successful in 16/18 (88.8%) cases. There were seven peri-procedural failures requiring surgery to repair the femoral artery in three cases. Four access complications healed without intervention. Overall 25/29 (86.2%) patients had complete percutaneous repair. No late complications were detected during follow-up (median 17.5 months).

CONCLUSIONS

Percutaneous treatment of patients with AAA and thoracic aneurysms is feasible in most cases, with a very low risk of access-related complication, providing that the operator has sufficient practical experience of this technique.

[Interest of D-lactate as a colic hypoperfusion marker during aortic abdominal aneurysm surgery]

OBJECTIVE

D-lactate is the dextrogyre form of the lactate usually measured in intensive care. Its bacterial origin should make it a marker of translocation during gut ischemia. The aim was to test D-lactate as a postoperative marker of colic hypoperfusion measured during aortic surgery.

STUDY DESIGN

Prospective observational cohort study.

PATIENTS AND MEASUREMENTS

Patients operated for abdominal aortic aneurysm. Two groups were stratified on inferior mesenteric arterial residual pressure (IMArP) measured during the surgery: Colic hypoperfusion during surgery (CHs) group: patients with an IMArP < 40 mmHg.

CONTROL GROUP

patients with an IMArP > or = 40 mmHg. Baseline data such as age, duration of aortic clamping and severity score (IGS II) were collected. The D-lactate was measured in postoperative at admission time in ICU and then daily. D-lactate(max) defined the maximum value of D-lactate for one patient.

MAIN RESULTS

Twenty-nine patients were included, 23 in the control group and 6 in the CHs group. Groups were comparable at baseline. D-lactate(max) was significantly higher in the CHs group (median: 0.13 mmol/l; min-max: 0.03-0.9 mmol/l) than in the control group (0.03; 0-0.26 mmol/l, p=0.007).

CONCLUSION

D-lactate could be postoperative marker of colic hypoperfusion measured during surgery for abdominal aortic aneurysm.

[Infectious or inflammatory aortitis? One case report]

INTRODUCTION

The infectious or inflammatory nature of an aortitis is difficult to assert because the microbiological results are often negative. The development of an aneurysm under treatment is rare, but requires a change in the therapeutic strategy and the etiologic diagnosis needs to be discussed again.

EXEGESIS

We report the case of a 69-year-old woman treated by corticotherapy for an aortitis thought to be inflammatory, who required emergency surgery when a dissected aneurysm appeared. The peroperative samples were positive to Streptococcus pneumoniae using polymerase chain reaction and allowed a change of the diagnosis. The patient evolved favorably under antibiotic therapy.

CONCLUSION

The decision to treat an aortitis by corticotherapy must be made with caution even if the microbiological tests are negative.

Closure of carotid bifurcation endarterectomy using a polyurethane patch. A multicentre prospective study with 252 patients

BACKGROUND

In order to evaluate the results of carotid endarterectomy with closure using a polyurethane patch, a multicentre prospective study of 252 patients (263 interventions) undergoing this operation was performed between November 1996 and August 2001.

METHODS

One hundred and seventy-one men and 81 women with a mean age of 70 years were studied. Fifty-five percent of the patients had neurological symptoms. The degree of carotid stenosis evaluated using the European carotid surgery trialist's collaborative group (ECST) criteria was greater than or equal to 70% in 95% of cases.

RESULTS

The combined mortality-morbidity operation rate (CMMR) was 2% (1 death from cerebrovascular haemorrhage on Day 3, 1 non-regressive cerebrovascular accident (CVA), 3 regressive CVAs). The patients had follow-up clinical examinations and Doppler ultrasound scans for 2 years. Fifteen patients died during follow-up, 8 of these patients died from heart-related causes and 2 patients died from CVA. Four patients presented with CVAs ipsilateral or contralateral to the endarterectomy. Two false aseptic aneurysms and 1 false septic aneurysm required further surgery. Three asymptomatic carotid occlusions occurred during follow-up. The rate of restenosis greater than 50% was 1.2% at 6 months, 2.3% at 1 year and 5.3% at 2 years.

CONCLUSIONS

These results confirm the value of po-lyurethane patch closure of carotid endarterectomy.

Endoluminal smooth muscle cell seeding limits intimal hyperplasia

PURPOSE

Intimal hyperplasia is one of the main responses of the vascular wall to injury. In the current study, we tested the hypothesis that endoluminal seeding of host syngeneic vascular cells could limit intimal hyperplasia induced by either mechanical deendothelialization or chronic allograft rejection in rat aorta.

METHODS

An experimental model of in situ seeding of syngeneic endothelial cells, smooth muscle cells (SMCs), and fibroblasts (FIBs) was used in mechanically deendothelialized and allografted aortas. In a preliminary study, the ability of the three cell types (n = 5 per group) to seed on the deendothelialized luminal surface of the aortic wall was evaluated after 2 days, with the use of fluorescent PKH as marker. In the first model, the abdominal aorta of Lewis rats was deendothelialized (n = 6) or deendothelialized and seeded with either SMCs (n = 6) or FIBs (n = 6) before flow was restored. In the allograft model, aortas were harvested from dark agouti rats and orthotopically grafted in Lewis receivers, directly (n = 6) or after deendothelialization. Deendothelialization was performed alone (n = 6) or associated with the seeding of similar host (Lewis) syngeneic SMCs (n = 6) or FIBs (n = 6). Results were evaluated at 2 months with histologic and morphometric methods.

RESULTS

SMCs and FIBs were able to adhere in situ to the deendothelialized aortic wall, whereas endothelial cells were not. In mechanically deendothelialized aortas, the seeding of syngeneic SMCs led to a significant reduction in intimal thickness compared with deendothelialized aortas or FIB-seeded aortas (26.9 +/- 1.7 microm vs 55.5 +/- 1.7 and 56.7 +/- 1.7 microm, respectively), and a lower nuclear content (382.2 +/- 35.7 microm(2) vs 779.6 +/- 65.9 and 529.6 +/- 24.3 microm(2), respectively) of neointima. After SMC seeding, intimal hyperplasia was richer in elastin, whereas after FIB seeding it was richer in collagen. In allografts, the seeding of syngeneic SMC led to a significant reduction in intimal thickness compared with control aortas, deendothelialized aortas, or FIB-seeded aortas (31.6 +/- 1.1 microm vs 88.55 +/- 2.8, 74.6 +/- 2.9, and 85.7 +/- 2.6 microm, respectively), and a reduced nuclear content of the neointima (444.9 +/- 23.4 microm(2) vs 1529.1 +/- 116, 972.3 +/- 50, and 645.2 +/- 32.4 microm(2), respectively). Differences observed in the extracellular matrix composition were equivalent to those observed in the mechanically deendothelialized model.

CONCLUSIONS

Our results suggest that endoluminal seeding of syngeneic SMCs can be effective in reducing intimal hyperplasia both in a deendothelialization model and in arterial allografts. SMC and FIB endoluminal seeding led to a significatively different accumulation of extracellular matrix in the intima.

[Humoral effectors and cellular targets of chronic arterial wall allorejection]

Contrasting with acute rejection, chronic rejection of arterial allograft don't involve leukocyte passengers from the graft to the host. Chronic rejection involves the proteins of the major histocompatibility complexes. Experimental studies in rats showed that the process evolved in three stages: a first stage of histo-incompatibility recognition mediated by the graft endothelium, a second stage of immune antibody-dependent injury of allogenic smooth muscle cells of the media associated with inflammatory infiltration of the adventitia, lastly a third stage of scarring process including intimal proliferation and adventitial fibrosis.

Prosthetic graft infection after descending thoracic/ thoracoabdominal aortic aneurysmectomy: management with in situ arterial allografts

PURPOSE

Prosthetic graft infection is an uncommon but life-threatening complication of descending thoracic/thoracoabdominal aortic aneurysmectomy. The purpose of this study was to assess the value of in situ arterial allografts in the management of this complication.

METHODS

From 1992 to 2000 we treated 11 consecutive patients with prosthetic graft infection after descending thoracic/thoracoabdominal aortic aneurysmectomy by replacing the prosthetic graft with an in situ arterial allograft. There were 10 men and one woman with a mean age of 50.8 years (range, 32-73 years). The primary aortic disease was degenerative aneurysm in 6 patients, chronic type B dissection in 2 patients, inflammatory aneurysm in 1 patient, Marfan's disease in 1 patient, and Behçet's disease in 1 patient. Replacement involved only the descending thoracic aorta in three patients and more or less extensive segments of the thoracoabdominal aorta in eight patients. Signs of severe infection were present in all patients, and false anastomotic aneurysms were noted in six patients. Aortoenteric fistula occurred in three patients and aortobronchial fistula in two patients. The causative organisms were identified in nine patients. The mean interval between the primary surgery and reoperation was 33.4 +/- 27.5 months. Reoperation was performed under emergency conditions because of hemorrhage in three patients. Cardiopulmonary bypass with deep hypothermic circulatory arrest was used in seven patients. Allograft replacement of the aorta was associated with reimplantation of intercostal and/or visceral arteries in all patients.

RESULTS

One patient died intraoperatively of heart failure during emergency surgery. Two patients died of persistent infection during the postoperative period at 19 and 58 days. Mean follow-up was 34 +/- 19 months. One patient died during the late follow-up period after surgery of the infrarenal aorta. Another patient underwent surgery for stenoses of one branch of a bifurcated allograft and a renal bypass graft to a solitary kidney.

CONCLUSIONS

The use of in situ arterial allografts is a significant advance in the management of prosthetic graft infection after descending thoracic/thoracoabdominal aortic aneurysmectomy provided that reoperation is performed early.

Involvement of antibody-dependent apoptosis in graft rejection

BACKGROUND

Both humoral factors and apoptosis have been recently suggested to play a role in chronic allograft rejection. However, a link between alloantibodies and grafted cell apoptosis has never been proposed. Using the aortic allograft model in the rat, we have previously demonstrated the presence of IgG associated with the disappearance of donor endothelial and medial smooth muscle cells. In the present study, we tested the interaction between recipient allosera, enriched with antibodies by presensitization, and primary culture of cardiovascular cells of donor origin.

METHODS

For this purpose endothelial cells, smooth muscle cells, adventitial fibroblasts, and cardiac myocytes of donor origin were cultured. Binding of alloantisera to these cells was analyzed by flow cytometry. Apoptosis of donor cells was evaluated by Tdt-mediated d' UTP-FITC nick end labeling, 4',6-diamidino-2-phenylindole and DNA ladder techniques. The alloantisera were compared with anti-MHC class I monoclonal antibodies. Finally the colocalization of antibodies and apoptosis was investigated in vivo.

RESULTS

In vitro, alloantisera bind to cardiovascular cells of donor origin. These cells expressed MHC class I but not MHC class II. There was a partial competition between anti-MHC I mouse monoclonal antibody and alloantisera mainly of the IgG isotype. Alloantisera bound to, but did not induce lysis of, donor RBC. Alloantisera induced apoptosis of donor cardiovascular cells as assessed by the typical morphological aspect of the donor cells after 24 hr of incubation. These data were confirmed by the Tdt-mediated d' UTP-FITC nick end labeling positivity of the cells and the fragmentation of the nucleus visualized by 4',6-diamidino-2-phenylindole and DNA ladder techniques. Similar apoptosis was induced by specific monoclonal antibodies directed against the MHC class I of donor cells. Primary culture of similar vascular cells of recipient origin was insensitive to alloantisera directed against donor alloantigens. Finally, in vivo, using allopresentization and aortic allografts, an association of alloantibody binding and endothelial cell apoptosis was observed at day 5, and a similar association with smooth muscle cell apoptosis on day 12 after grafting.

CONCLUSION

These data demonstrate the role of humoral injury in chronic allograft rejection and suggest new therapeutical approaches focused on the induction of resistance to antibody-dependent apoptosis.

[Inflammatory abdominal aortic aneurysm. Role of corticosteroid therapy]

For more than 20 years it has been generally acknowledged that operation for inflammatory abdominal aortic aneurysm (IAAA) using the common in-lay-graft procedure will induce the regression of peri-aortic fibrosis. However in prospective studies, after a 2 years follow-up, no regression appeared in approximated 8% of the cases (table I). Moreover in some IAAA a corticosteroid treatment (CS) was prescribed and it produced a regression of fibrosis and therefore facilitated the operation. Nevertheless the usefulness of the CS remains debated. We report 4 new cases of IAAA with CS. Based on our cases and an analysis of the literature we conclude that when there is no urgency to operate (diameter inferior to 50 mm) CS is the best option in IAAA with either severe inflammation or ureter involvement. Due to the regression of the fibrosis it can facilitate the surgical procedure. However it needs to be conducted with an adequate dose and duration. Finally the CS is the only possibility when the inflammation persist following the treatment of the IAAA.

Bacterial resistance of refrigerated and cryopreserved aortic allografts in an experimental virulent infection model

PURPOSE

The bacterial resistance of refrigerated and cryopreserved aortic allografts in a highly virulent infection in a dog model was studied.

METHODS

The infrarenal aorta of 12 dogs was replaced with either a cryopreserved aortic allograft (group I, n = 6) or a refrigerated aortic allograft (group II, n = 6) in infected sites. Allografts were harvested from dogs and stored for 1 week, either by cryopreservation (-140 degrees C) or refrigerated method (4 degrees C), in a preservation medium. At the time of implantation, induction of infection was achieved with an infected piece of knitted Dacron placed just beneath the allograft. The Dacron was contaminated in vitro by soaking it in a solution with Staphylococcus aureus PR209. All 12 dogs received no adjunct antibiotic or antithrombotic therapy. Four weeks after implantation, the animals were killed to recover the grafts for bacteriological and histological analyses. Bacterial results were expressed as colony-forming units (CFU)/cm2 of graft material.

RESULTS

In group I, only one allograft grew bacteria at 2. 16 x 10(6 )CFU/cm2, with a blood culture positive for S aureus. In group II, one dog died at 3 weeks from a false septic aneurysm rupture, all the allografts were infected (P <.05) with a mean bacterial count of 9.41 +/- 6.8 x 10(4) CFU/cm2, and three blood cultures were positive for S aureus. The patency of the grafts was analyzed at the time of recovery. Three laminar thrombi without occlusion were present in group I; none were present in group II. A better preserved endothelium in group I was revealed by means of histologic analysis staining with factor VIII antibody before implantation. After 4 weeks of implantation in the infected site, infected allografts presented polynuclear infiltrates in the media with a high degree of inflammatory reaction, and endothelial recovery was more significant in group I, with numerous young plump cells.

CONCLUSION

This study demonstrates that cryopreserved allografts implanted in infected sites in a dog model can produce greater bacterial resistance.

Prosthetic reinforcement of varicose saphenous vein grafts for infrainguinal bypass

Use of varicose saphenous veins for infrainguinal bypass is often contraindicated because of the risk of immediate rupture or long-term aneurysm. In this report we describe four cases in which prosthetic reinforcement allowed successful femoropopliteal bypass grafting using highly varicose saphenous veins while preserving normal endothelium. No thrombosis or any other complication was observed after a mean follow-up of 41 months.

[Surgery of carotid lesions after irradiation. Apropos of 15 cases]

Out of 15 patients operated on for a carotid stenosis 3 to 19 years after a cervical irradiation, 2 were treated by a subclavian-carotid by-pass, 3 by a common carotid-internal carotid by-pass, 10 by an endarterectomy (6 closed with a patch), 3 of these endarterectomy extended largely down on the common carotid. Although the surgical approach was often difficult through the sclerotic tissues and 8 times the scar of a lymphadenectomy, the removal of the atherosclerotic core was as easy as usual. We observed neither mishap in arterial and cutaneous healings nor post operative stenotic myointimal hyperplasia.

Femoropopliteal bypass: in situ or reversed vein grafts? Ten-year results of a randomized prospective study

One hundred femoropopliteal bypass procedures performed in 91 patients between October 1980 and January 1985 were randomly divided into two statistically comparable groups including 50 in situ vein grafts and 50 reversed vein grafts. The indication for bypass was chronic critical ischemia in 97% of cases. The lower anastomosis was made on the distal popliteal artery in 75% of cases. Follow-up ranged from 10 years (for the last patient included) to 14 years. Three patients have been lost to follow-up. Median survival was 54 months in the in situ graft group and 76.5 months in the reversed graft group. Actuarial survival at 10 years was 30.8% in the in situ graft group and 29.5% in the reversed graft group. Actuarial limb salvage at 10 years was 73.5% in the in situ graft group and 74.4% in the reversed graft group. Graft occlusion was observed in 10 cases during the perioperative period (six in the in situ graft group and four in the reversed graft group) and in 19 cases during the late postoperative period (12 in the in situ graft group and seven in the reversed graft group). Reoperation during follow-up was required in 13 cases in the in situ graft group (11 patients) and in nine cases in the reversed graft group (five patients). Discounting residual arteriovenous fistulas (FAV) (five ligations in four patients), the incidence of lesions involving the bypass and anastomoses threatening graft patency was 6% in the in situ graft group and 8% in the reversed graft group. Actuarial primary patency at 10 years was 41.7% in the in situ graft group and 64.5% in the reversed graft group (p < 0.05). Actuarial secondary patency at 10 years was 64.8% in the in situ graft group and 70.2% in the reversed graft group (NS). As a function of vein diameter, actuarial secondary patency at 10 years in the in situ graft group was 37.5% for bypasses using veins with a diameter of 4 mm or less and 80.6% for bypasses using veins larger than 4 mm (p < 0.05). In the reversed graft group the patency rate was 71.2% for bypasses using veins with a diameter of 4 mm or less and 65.5% for bypasses using veins larger than 4 mm. In addition to requiring a training period the in situ technique raises the problem of valve removal especially for small diameter veins. The absence of these disadvantages makes the reversed technique the procedure of choice for femoropopliteal bypass.

[Lumbar sympathectomy by retroperitoneal endoscopy: feasibility study]

Endoscopic surgery has been used as a new procedure to simplify different surgical processes. The goal of this study was to evaluate the benefits of endoscopic retroperitoneal surgery for lumbar sympathectomies. Between February 93 and November 95 we performed 35 lumbar sympathectomies using this technique. All patients were arteritic. The results were as follows: for 25% of the patients, conversion classical open technique was required; 6% complications (septic); 3% of the patients died. In comparing the various techniques of sympathectomy and sympatholysis, it would appear that the endoscopic technique produces fewer complications. However we believe that a learning period is necessary before this technique can be fully mastered.

Presensitization accelerates allograft arteriosclerosis

Transplant arteriosclerosis is the major factor influencing allograft survival after the first year posttransplantation. The host's immunologic response is one of the principal effectors responsible for the constitution of this vascular wall lesion, but the effector pathway and the factors influencing the immune injury are not clear. In a rat abdominal aortic allograft model, we used a skin priming method to study the influence of sensitization on the occurrence of vascular wall lesions. Primed rats developed transplant arteriosclerosis lesions involving medial decellularization and intimal proliferation before the 21st day, whereas naive animals had the same lesions at 2 months posttransplantation. A significant difference between primed and naive rats was found for medial thickness (48.00 +/- 2.85 microm versus 79.34 +/- 2.55 microm, P<0.001) and smooth muscle cell content (160 +/- 28 cell/mm versus 466 +/- 19 cell/mm, P<0.001) at 21 days posttransplantation, and intimal hyperplasia was seen in primed animals at that time, whereas it was not observed in naive rats until the 60th day. The immune profile in naive and primed animals was different. The immune cells infiltrating the arterial wall in naive rats, were principally macrophages and CD8+ T-lymphocytes. No Ig or complement deposition was detected. IgG and complement activated fraction were present in the media of primed animals as early as the fifth day posttransplantation and CD4+ T lymphocytes were the dominant immune cell population. In conclusion, sensitization influences the immune mechanisms responsible for the development of transplant arteriosclerosis and alters the rate of its evolution.

In situ arterial allografting for aortoiliac graft infection: a 6-year experience

Between October 1988 and May 1994, all aortoiliac graft infections seen in the authors' service were treated by in situ arterial allografting after resection of any infected graft or tissue. Some 83 consecutive cases were treated; there were 68 isolated primary prosthetic infections (82%) and 15 aortoenteric fistulae (18%). Emergency arterial allografting was performed in five cases (6%), elective allografting in 64 cases (77%) and elective allografting after emergency palliative revascularization using a temporary prosthetic graft in 14 cases (17%). Arterial allografts were harvested from cadavers as part of a programme to retrieve multiorgan transplant tissue. Fifteen patients (18%) died either intra- or postoperatively. Three died during the operation, one from septic shock and two from uncontrollable coagulopathy. Twelve patients died in the early postoperative period, from from septic shock, two from myocardial infarction, two from pneumonia, one from a pulmonary embolism, one from an intestinal infarction, one from recurrence of a duodenal fistula and one from disruption of the native aorta at the suture line. Three patients presented with an early complication directly related to the use of the allograft. Eleven early survivors of the series died during follow-up. Among these late deaths, only one could likely be allograft-related. In four patients, the aortic segment of the allograft was mildly dilated on late computed tomography scan; three were reoperated on for disruption of the extra-abdominal segment of their allograft. All four cases were managed with simple suture of the allograft or with the use of a new allograft. Fifteen patients exhibited 19 late occlusive lesions of their allograft; 17 of these lesions had to be treated either with transluminal angioplasty or with surgery using autogenous or allograft material. In all but one case, secondary patency could be achieved through these additional procedures. Late occlusive disease was more prevalent in the femoral segment of the allograft than in the iliac or, moreover, the aortic segment. There were no late amputations in this series.

[Treatment of prostheto-digestive using arterial allograft]

From October 1988 to March 1995, we operated 22 patients for fistulization between the prosthesis and the digestive tract to remove the in situ allograft. The delay between the initial operation and treatment for fistulization was 7.3 +/- 4 years. In these patients who had undergone multiple operations (2.5 +/- 1.9 operations per patient), the infected prosthesis was made of Dacron in 21 cases and polytetrafluoroethylene in one. The procedure was planned beforehand in 21 cases who benefited from a complete preoperative work-up and was required in an emergency situation in 6 for digestive bleeding (5 cases) or an abscess of the Scarpa (1 case). Among the patients with an emergency operation, three of the procedures were conducted within a single operative time and three with two separate procedures. The allografts were aorto-aortic tubes (n = 3), aortobifemoral bypasses (n = 14), aorto-iliac bypasses (n = 4) and one aorto-femoral-iliac bypass. Organ revascularization was associated in 8 patients. Seven patients (32%) died post-operatively. Five of them had undergone an emergency procedure. An amputation was required in 2 patients, one at the time the allograft was implanted and the second due to ischaemia despite a permeable allograft. None of the patients had to be amputated due to failure of the allograft. Mean follow-up was 36.6 +/- 20 months. There were 4 deaths post-operatively due to digestive bleeding in 2. The aortic allograft was dilated in 4 patients without re-operation. Thrombosis of the allograft branch occurred in 4 patients, including 3 who had been re-operated successfully. Despite these still perfectable results, treatment of secondary digestive-prosthesis fistulae with an in situ allograft constitutes a real progress in terms of patient survival and preservation of the limb in high-risk patients.

Sequential immunological targeting of chronic experimental arterial allograft

Arterial wall is the main site involved in the chronic rejection process. The rat aortic allograft model was used here to characterize and describe the sequential evolution of the different targets and effectors of arterial wall immunological injury and response during arterial allograft rejection. Rat abdominal aortae were isografted or allografted from Brown-Norway to Lewis rats. Endothelial and smooth muscle cell injury and humoral and cellular immunological effectors were characterized from 0 to 60 days after transplantation using a battery of specific antibodies. The intimal proliferative response was also characterized over this time. Isografted Brown-Norway aorta adventitia had very few cellular components, which suggests that donor adventitia would be poorly antigenic in allografts. In contrast, allograft adventitia was the site of a major inflammatory cell invasion in which the expression of an adhesion molecule by colonizing capillary endothelial cells could play a main role. This adventitial infiltration continued as long as medial smooth muscle persisted. The luminal endothelial cells disappeared early, probably associated with macrophage margination. In contrast, medial smooth muscle cell disappearance occurred later and was specifically targeted by immunoglobulins. Intimal proliferation was the most delayed phenomenon, involving both inflammatory cell infiltration at an early stage and later myofibroblastic proliferation, and could be related to the specific expression of growth factors in this layer. The rat aortic allograft model appeared useful for characterizing specific targets and effectors of chronic arterial graft rejection, demonstrating an early stage of endothelial injury and the presence of immunoglobulins involved in chronic medial smooth muscle cell injury.

Cell-free arterial grafts: morphologic characteristics of aortic isografts, allografts, and xenografts in rats

PURPOSE

Chronic rejection of arterial allografts and xenografts results in arterial wall dilation and rupture, making them unsuitable for long-term arterial replacement in vascular surgery. In the arterial wall, as in other organs, the cells probably carry major antigenic determinants. Arterial wall cellular components can be removed by detergent treatment to produce a graftable matrix tube.

METHODS

We compared the patency and macroscopic and microscopic morphologic changes that occurred in sodium dodecyl sulfate (SDS)-treated and untreated arterial isografts, allografts, and xenografts 2 months after implantation in rats. We quantified elastin, collagen, and nuclear density in the three layers of the graft wall (intima, media, and adventitia) by morphometric methods. The SDS treatment removed endothelial and smooth muscle cells and cells in the adventitia but preserved elastin and collagen extracellular matrix.

RESULTS

All arterial xenografts, whether SDS treated or untreated, were aneurysmal 2 months after grafting, with loss of the medial cellular and extracellular components. In allografts, SDS treatment prevented dilation, reduced adventitial inflammatory infiltration, and preserved medial elastin. The SDS-treated allografts had an evenly distributed, noninflammatory intimal thickening that was richer in elastin fibers than that in untreated allografts.

CONCLUSIONS

These results suggest an interspecies, but not an intraspecies, graft antigenicity of arterial extracellular matrix. The SDS treatment prevented chronic rejection of the arterial allograft and led to the proliferation of an elastin-rich and adapted intima.

In situ allograft replacement of infected infrarenal aortic prosthetic grafts: results in forty-three patients

PURPOSE

Dissatisfaction with conventional methods of treatment of infected infrarenal aortic prosthetic grafts and excellent long-term results reported by heart surgeons after allograft replacement for management of infections involving the ascending aorta have prompted us to investigate allograft replacement in the management of arterial infections.

METHODS

From October 1988 to April 1992, 43 consecutive patients with infected infrarenal aortic prosthetic grafts underwent in situ replacement with preserved allografts obtained from cadavers as part of a program to retrieve multiorgan transplant tissue. Thirty-four patients had isolated prosthetic infections, whereas nine had aortoenteric fistulas. One patient had a concomitant below-knee amputation for septic arthritis of the ankle as a result of septic emboli. Nineteen patients had nonvascular-associated procedures, including 17 intestinal procedures.

RESULTS

Five patients (12%) died after operation: four of general causes and one of rupture of the native aorta as a result of persistent infection. Three patients successfully underwent repeat operation for allograft-related complications (one case each of occlusion, septic rupture, and graft-enteric fistula). All surviving patients were discharged after control angiography showed patent allografts. Two patients were unavailable for follow-up. The other 36 patients have been monitored with serial duplex and computed tomography scanning for a mean follow-up of 13.8 months (range 1 to 42 months). There were four late deaths: three were unrelated to the vascular operation, and one may have been caused by late persistent or recurrent infection. Nine patients (26%) have had pathologic changes in the allograft, with three (9%) requiring repeat operation. There were no early or late postoperative amputations in the entire series.

CONCLUSIONS

Although complete protection against persistent or recurrent infection has not been achieved and late deterioration may be expected, in situ allograft replacement seems to be a major advance in the management of infected infrarenal aortic prosthetic grafts.

Additive and synergistic effects of a low-molecular-weight, heparin-like molecule and low doses of cyclosporin in preventing arterial graft rejection in rats

Arteriosclerotic intimal proliferation is one of the main long-term complications of organ transplantation. Low-molecular-weight, heparin-like molecules prevent myointimal proliferation in arterial wall injury and limit rejection in skin allografts. Cyclosporin limits rejection but has no major effect on intimal proliferation. Therefore, an experimental protocol was designed to test whether heparin-like molecules interacted with low doses of cyclosporin to prevent arterial wall immune system injury and response in a model of arterial graft rejection in normotensive and hypertensive rats. Aortic allografts were performed in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) normotensive control rats. Four groups of 10 allografted (SHR and WKY) rats were used: one group was treated with placebo, one with low doses of cyclosporin (2 mg/kg body wt per day), one with low-molecular-weight, heparin-like molecule (1 mg/kg body wt per hour), and one with low doses of cyclosporin plus low-molecular-weight, heparin-like molecule. Ten SHRs and 10 WKYs were isografted and served as the control groups. All rats were killed 8 weeks after aortic grafting. Structural parameters of the grafted segment were measured by morphometric analysis on formalin-fixed sections with specific stains. The classical signs of immune system injury and response were present in the untreated allografts in SHRs and WKYs: inflammatory infiltration of the adventitia, medial injury, and intimal proliferative response. Low doses of cyclosporin had a significant beneficial effect on immune medial injury by increasing medial thickness and the number of remaining smooth muscle cells and decreasing the extracellular matrix injury. Cyclosporin had no protective effect on intimal proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of glutaraldehyde on experimental arterial iso- and allografts in rats

The effects of glutaraldehyde pretreatment and allograft rejection in arterial grafts were assessed, using iso- and allografts in rats. An in situ glutaraldehyde fixation procedure was used to obtain homogeneous cross-linked vascular biografts. Ten Lewis rats were isografted, ten were isografted with a glutaraldehyde-treated aortic segment, ten were allografted with aortic segments from brown Norway (BN) inbred rats, and ten were allografted with glutaraldehyde-treated BN aortas. The macroscopic and microscopic appearances of the grafts were analyzed 3 weeks after the initial surgery. Immunological injury to the media and the intimal response were quantified morphometrically after monochromatic staining of cell nuclei (hematoxylin after periodic acid), elastin (orcein), and calcification (Von Kossa). Untreated isografts were normal. Untreated allografts showed the classical signs of arterial wall rejection: adventitial inflammatory granuloma, reduced medial thickness and smooth muscle cell density, and greatly increased intimal thickness (P < 0.005). Glutaraldehyde treatment significantly decreased the medial thickness in both iso- and allografts (P < 0.001) and prevented the intimal proliferative response (P < 0.005), but did not change adventitial inflammation. It also induced massive calcification mainly in isografts (P < 0.001). Histomorphological modifications of glutaraldehyde-treated grafts are consistent with a partial protective effect of glutaraldehyde against the rejection process, but also with an induction of a nonspecific inflammatory reaction. Glutaraldehyde-induced cross-linking of the extracellular matrix was responsible for ectopic calcification of the arterial grafts which was independent of the rejection process.

Effect of perindopril on the immune arterial wall remodeling in the rat model of arterial graft rejection

A model of arterial graft arteriosclerosis is described in which arterial wall immune injury was induced by grafting segments of abdominal aorta between two histologically incompatible strains of rats. The effect of hypertension and its treatment with the angiotensin-converting enzyme (ACE) inhibitor perindopril was tested using inbred spontaneously hypertensive rats (SHR) and their normotensive controls (Wistar-Kyoto [WKY]). Each of the grafted hypertensive and normotensive rats was randomly allocated to placebo treatment (10 SHR, 10 WKY) and perindopril treatment (2 mg/kg/day) (10 SHR, 10 WKY). The immune injury and the arterial wall response were quantified morphometrically 2 months after the grafting using specific stains for collagen, elastin, and nuclei. Hypertension was associated with a significant increase in intimal thickness. Treatment with perindopril greatly reduced intimal proliferation, decreasing the intimal thickness and the collagen content within the intimal layer. In contrast, hypertension and ACE inhibition had little effect on the arterial wall injury. We conclude that hypertension and its treatment with perindopril significantly affect graft arteriosclerosis. These effects seem to be independent of their effects on arterial wall injury, but not independent of blood pressure.

Allograft-induced arterial wall injury and response in normotensive and spontaneously hypertensive rats

The role of genetically determined immune attack and blood pressure in graft rejection-induced arterial wall injury and response was assessed by studying the compliance and changes in wall structure of aortic isografts and allografts in normotensive (Wistar-Kyoto [WKY]) and hypertensive (spontaneously hypertensive [SHR]) rats. Six groups of 8-week-old rats were compared: sham-operated in both strains, isografts, and allografts between the two strains (SHR aortas grafted in WKYs, designated SWs; WKY aortas grafted in SHRs, designated WSs; isografts in SHRs, designated SSs; and isografts in WKYs, designated WWs). Each arterial graft was studied 8 weeks after transplantation for volume and compliance (pressures of 75-175 mm Hg) under basal conditions. The amounts of collagen, elastin, and nuclei in the media and intima of the walls of control and grafted aortas were quantified morphometrically. Isografts and controls had the same mechanical characteristics under basal conditions: the arterial volume and arterial compliance of hypertensive rats were lower than those of normotensive rats (p less than 0.001). Allografts had a greater initial volume (p less than 0.001) and a lower compliance (p less than 0.001) than did isografts. Allografts in SHRs (SSs) were initially dilated, whereas allografted WKYs (WWs) were not. There was intimal proliferation in hypertensive isografts (14 +/- 0.77 microns) and in both types of allografts (WS, 69 +/- 1.55 microns; SW, 44 +/- 1.81 microns); nucleus density was higher in hypertensive allografts (WS) than in normotensive allografts (SW); and collagen density was also higher in SW than in WS allografts. Allografts had decreased medial thickness and decreased smooth muscle cell density.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of converting enzyme inhibition on allograft-induced arterial wall injury and response

Converting enzyme inhibition (CEI) can prevent myointimal proliferation after arterial wall balloon injury. Because intimal proliferation is the main long-term complication of chronic vascular rejection, we tested the effect of CEI (perindopril, 1 mg/kg twice a day) on arterial rejection-induced intimal proliferation, using a model of aortic allograft in normotensive Wistar-Kyoto and spontaneously hypertensive rats. Eight-week-old rats were grafted and studied 2 months later. The structural parameters of the transplanted aortic wall were measured by morphometric analysis of specifically stained, formol-fixed sections. CEI did not prevent adventitial inflammatory infiltration but significantly increased the number of living cells and prevented the partial destruction of elastic laminae in the media, thereby increasing medial thickness to close to that of sham-operated controls. CEI significantly decreased intimal thickness and intimal collagen density, without changing the absolute number of intimal smooth muscle cells. The intimal thickness and the intimal collagen density were significantly correlated with the effect of CEI on blood pressure. CEI partially prevented the consequences of immune injury to the media within the arterial wall, probably by suppressing the proinflammatory activity of angiotensin II. It also decreased the recipient arterial wall response by acting more on the trophicity of intimal cells and on their ability to produce collagen rather than by directly inhibiting smooth muscle cell proliferation in our model of arterial allograft.