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

Contemporary outcomes for arterial reconstruction with non-saphenous vein cryo-preserved conduits

OBJECTIVE

Cryopreserved (CP) products are utilized during challenging cases when autogenous or prosthetic conduit use is not feasible. Despite decades of experience with cadaveric greater saphenous vein (GSV), there is limited available data regarding the outcomes and patency of other CP products, specifically arterial and deep venous grafts. This study was designed to evaluate outcomes of non-GSV CP conduits in patients undergoing urgent, emergent, and elective arterial reconstruction at our institution. We hypothesized that non-GSV CP allografts have adequate patency and outcomes and are therefore a feasible alternative to GSV in settings where autologous graft is unavailable or prosthetic grafts are contraindicated.

METHODS

This study was approved by the Institutional Review Board at our institution. We retrospectively reviewed charts of patients undergoing arterial reconstructions using CP conduits from 2010 to 2022. Data collected included demographics, comorbidities, smoking status, indications for surgery, indication for CP conduit use, anatomic reconstruction, urgency of procedure, and blood loss. Time-to-event outcomes included primary and secondary graft patency rates, follow-up amputations, and mortality; other complications included follow-up infection/reinfection and 30-day complications, including return to the operating room and perioperative mortality. Time-to-event analyses were evaluated using product-limit survival estimates.

RESULTS

Of 96 identified patients receiving CP conduits, 56 patients received non-GSV conduits for 66 arterial reconstructions. The most common type of non-GSV CP product used was femoral artery (31 patients), followed by aorto-iliac artery (22 patients), and femoral vein (19 patients), with some patients receiving more than one reconstruction or CP product. Patients were mostly male (75%), with a mean age of 63.1 years and a mean body mass index of 26.7 kg/m2. Indications for CP conduit use included infection in 53 patients, hostile environment in 36 patients, contaminated field in 30 patients, tissue coverage concerns in 30 patients, inadequate conduit in nine patients, and patient preference in one patient. Notably, multiple patients had more than one indication. Most surgeries (95%) were performed in urgent or emergent settings. Supra-inguinal reconstructions were most common (53%), followed by extra-anatomic bypasses (47%). Thirty-day mortality occurred in 10 patients (19%). Fifteen patients (27%) required return to the operating room for indications related to the vascular reconstructions, with 10 (18%) cases being unplanned and five (9%) cases planned/staged. Overall survival at 6, 12, and 24 months was 80%, 68%, and 59%, respectively. Primary patency at 6, 12, and 24 months was 86%, 70%, and 62%, respectively. Amputation freedom at 6 months, 12 months, and 24 months was 98%, 95%, and 86%, respectively for non-traumatic indications.

CONCLUSIONS

Non-GSV CP products may be used in complex arterial reconstructions when autogenous or prosthetic options are not feasible or available.

Transplantation of cryopreserved cardiovascular homografts

Due to degeneration, homografts were since the 1950s only used strictly for replacement of complex arterial segments and lesions incl. the aortic valve, replacement of infected arterial prostheses, and vascular access for patients on haemodialysis. During the 1990s, rate-differentiated freezing methods and anti-crystallization agents proved to prevent crystallisation, and more widespread use with expanded indications incl. coronary and lower limb bypasses began justified by promising midterm results. In 2021, the first Scandinavian homograft biobank was founded in Odense in Denmark. This review summarises the history and the experiences from this biobank.

Ten-year experience with cryopreserved vascular allografts in the Croatian Cardiovascular Tissue Bank

The Croatian Cardiovascular Tissue Bank (CTB) was established in June 2011. Activities managed by CTB are processing of heart valves and blood vessels, as well as quality control, storage, medical release and distribution of allografts. The aim of this report is to present CTB's vascular tissue activities and retrospectively evaluate the outcomes of their use in the University Hospital Centre Zagreb. Between June 2011 and July 2021, 90 vascular allografts (VAs) from 55 donors after brain death were referred to CTB. Only 54% of VAs met the tissue quality requirements while 46% of tissues were discarded. The most frequent reasons for discard were unacceptable morphology and initial microbiological contamination. Altogether 42 VAs were released for transplantation and 37 of them were used in 27 surgical procedures. The most common indication for surgery was prosthetic graft or stent infection. According to the anatomic position of vascular reconstruction, patients were divided in the aortic and peripheral reconstruction group. A total of 23 patients were treated. In the aortic reconstruction group 58% of patients did not experience any graft-related complications. In the group of patients who underwent peripheral reconstruction significant incidence of reinfection was observed highlighting it as a major graft-related complication. Despite the small patient groups and limited duration of follow-up, presented clinical outcomes provide valuable information on the efficacy of vascular allografts. Additional clinical results collected on a larger patient groups and comparison to other reconstructive treatment options are necessary.

In situ repair or reconstruction of the abdominal aorta-iliac artery by autologous fascia-peritoneum with posterior rectus sheath for the treatment of the infected abdominal aortic and iliac artery aneurysms: A case series and literature review

Background

Infected abdominal aortic and iliac artery aneurysms are considered acute and severe diseases with insidious onset, rapid development, and high mortality in vascular surgery. Currently, there is no better treatment, either anatomic or extra-anatomical repair.

Case presentation

From February 2018 to April 2022, 7 patients with infected abdominal aortic and iliac artery aneurysms did not have sufficient autologous venous material for repair. With the consent of the Ethics Committee of the hospital, it uses the autologous peritoneal fascial tissue with rectus sheath to repair or reconstruct the infected vessels in situ. There were 5 cases of infected abdominal aortic aneurysm, 1 case of an infected common iliac aneurysm, and 1 case of the infected internal iliac aneurysm. Aortoduodenal fistula was found in 3 cases, all of them were given duodenal fistula repair and gastrojejunostomy and cholecystostomy. Three cases of infected abdominal aortic aneurysms were repaired with the autologous peritoneal fascial tissue patch, and 2 cases of infected abdominal aortic aneurysms were reconstructed by the autologous peritoneal fascial tissue suture to bifurcate graft in situ, the autologous peritoneal fascial tissue suture reconstructed the rest 2 cases of infected iliac aneurysm to tubular graft in situ. It was essential that Careful debridement of all infected tissue and adequate postoperative irrigation and drainage. Antibiotics were administered perioperatively, and all patients were subsequently treated with long-term antibiotics based on bacterial culture and susceptibility results of infected tissues and blood. All 7 patients had underwent surgery successfully. But there were 2 cases died of anastomotic infection or massive hemorrhage after the operation, the other 5 cases survived. The follow-up time was 2–19 months. The enhanced CT of postoperation showed that the reconstructed arteries were smooth without obvious stenosis or expansion, and no abdominal wall hernia occurred.

Conclusion

In situ repair or reconstruction with autologous peritoneal fascial tissue with rectus sheath is a feasible treatment for the infected aneurysm patients without adequate autologous venous substitute, but it still needs long-term follow-up and a large sample to be further confirmed.

Very Late Aortic Endograft Infection With Listeria monocytogenes in an Elderly Man

Endograft infection with Listeria monocytogenes is a rare, potentially devastating complication of endovascular aortic aneurysm repair. To our knowledge, only 8 cases have been reported. We describe the case of a 72-year-old man who presented with L. monocytogenes endograft infection and a 19-cm degenerative aneurysm 9 years after having undergone endovascular repair of an abdominal aortic aneurysm. The infection was successfully treated with open surgical excision of the infected aortoiliac endograft and its replacement with a rifampin-soaked, bifurcated Dacron graft.

Successful treatment of graft-duodenal fistula after renovisceral debranching thoracic endovascular aortic repair with limited graft resection based on 18F-fluorodeoxyglucose positron emission tomography with computed tomography

We present the case of a patient with a graft-duodenal fistula after renovisceral debranching thoracic endovascular aortic repair. ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography showed that the infection was localized to the renovisceral bypass grafts and the right kidney. Based on the preoperative imaging findings, a limited surgery with resection was performed in the fistula, right kidney, and fluorodeoxyglucose-positive bypass grafts, while preserving the fluorodeoxyglucose-negative grafts. No signs of reinfection were reported 2 years after the surgery. Accurate assessment of infection with ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography may be useful for performing adequate excision of infected lesions.

Editor's Choice - Cryopreserved Allografts for Arterial Reconstruction after Aorto-Iliac Infection: A Systematic Review and Meta-Analysis

OBJECTIVE

Native and aortic graft infections are rare, but they represent one of the most life threatening complications of vascular surgery. Several materials and surgical approaches have been developed so far. Among them, cryopreserved allografts have been proposed as a treatment option. A systematic review and meta-analysis was conducted to investigate the role of cryopreserved allografts for arterial reconstruction after aorto-iliac infection.

METHODS

The current meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patient baseline characteristics were investigated, along with 30 outcomes after use of cryopreserved arterial allografts for reconstruction after aorto-iliac infection. Pooled proportions with 95% CIs of outcome rates were calculated.

RESULTS

A total of 31 studies, including 1,377 patients, finally participated in the meta-analysis. Among the early outcomes, 30 day mortality was 14.91% (95% CI 11.78-18.31). Peri-anastomotic rupture/allograft disruption rate was 5.90% (95% CI 2.77-9.88), while pooled aneurysmal degeneration/allograft dilatation was 4.99% (95% CI 1.60-9.68). A pooled rate of 3.11% (95% CI 1.60-4.98) was estimated for pseudoaneurysm formation after the use of cryopreserved arterial allografts, while the allograft thrombotic/stenotic complication rate and peri-anastomotic infection were 12.19% (95% CI 7.90-17.15) and 3.32% (95% CI 1.90-5.03), respectively. Mortality during follow up was 19.24% (95% CI 11.97-27.58), while allograft related mortality during follow up was 3.58% (95% CI 1.56-6.15). A pooled allograft related re-operation rate was estimated at 24.87% (95% CI 17.89-32.51).

CONCLUSIONS

The use of cryopreserved allograft seems to be a safe and durable option with acceptable outcomes for treatment of aorto-iliac infection.

Systematic Review and Meta-Analysis on the Management of Open Abdominal Aortic Graft Infections

OBJECTIVE

Aortic graft infection (AGI) is a disastrous complication with an incidence of 0.2-6% in operated patients. With little or no high quality evidence, the best treatment option remains unclear. Therefore, the literature on the management of open abdominal AGI was systematically reviewed to determine optimal treatment.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review and meta-analysis was conducted for AGI. MEDLINE, Embase, and the Cochrane Database of Systematic Reviews were searched. Methodological quality was assessed using the Methodological Index for Non-randomised Studies (MINORS) score. Primary outcomes were 30 day mortality and one year survival. Secondary outcomes were survival, infection recurrence, limb salvage, and graft patency.

RESULTS

Of 1574 studies identified, 32 papers were included in the study. The overall quality of the studies was moderate, with an average MINORS score of 11.9. Pooled overall 30 day mortality and one year survival were 13.5% (95% CI 10.5-16.4) and 73.6% (95% CI 68.8-78.4), respectively. The lowest 30 day mortality and highest one year survival were found for in situ repair compared with extra-anatomic repair and for prosthetic grafts compared with venous grafts or arterial allografts. The infection recurrence rate was highest for prosthetic grafts.

CONCLUSIONS

There is a lack of well designed, qualitative comparative studies making conclusive recommendations impossible. The current best available data suggests that partial graft removal should be avoided and the lowest 30 day mortality and best one year survival are achieved with in situ repair using prosthetic grafts. Initiatives such as the MAGIC database to collaboratively collect prospective data are an important step forward in obtaining more solid answers on this topic.

Historical Overview of Vascular Allograft Transplantation

There is a mix of therapeutic options for revascularisation in vascular surgery. The authors performed a literature review on the evolution of vascular allograft transplantation and its use and acceptance by vascular surgeons. This review exposed three stages: the first stage involved preliminary experimentation; the second stage was a decline in use due to long-term complications, and the third stage is its current use in special indications subject to a thorough analysis. There are few indications for the use of vascular allografts in clinical guidelines. However, there are publications of long series of case studies with variable results reflecting international use of the procedure. There is a current trend that favours its use with limited and individualised indications.

Peripheral artery reconstructions using cryopreserved arterial allografts in infected fields

OBJECTIVE

Cryopreserved human arterial allografts are a recognized acceptable alternative for vascular reconstruction when other traditional conduits are either unavailable or contraindicated. We reviewed our experience using cryopreserved arterial allografts for peripheral artery reconstructions in contaminated and infected surgical fields.

METHODS

A single-center, retrospective review was conducted of 57 patients who underwent a peripheral vascular reconstruction using a cryopreserved arterial allograft from January 2002 through July 2017. Indications for repair included removal of infected prosthetic bypass (n = 29), revascularizations in contaminated fields (n = 11), primary arterial repair in the setting of infection (n = 10), and infected vascular closure devices (n = 7). Aorta-based repairs were excluded. Demographics, index procedural details, postoperative complications, and conduit patency were analyzed. Primary end points included conduit-related mortality and graft failure as measured by reinfection, hemorrhage, or aneurysmal degeneration. Mean follow-up for the study is 27.8 months (range, 2-125 months).

RESULTS

A total of 57 peripheral vascular reconstructions using cryopreserved arterial allografts were performed during the 15-year period. Among the 22 women and 35 men treated, the mean age was 61 years. The vascular beds involved included iliofemoral (n = 39), femoropopliteal or femoral-distal (n = 10), axillosubclavian or brachial (n = 2), mesenteric (n = 3), and carotid (n = 3) arteries. Adjunctive muscle flap coverage of the allograft conduit was performed in the majority of cases (61%; n = 35). The 30-day mortality was 9%; one death was directly related to conduit insertion. The 30-day conduit-related complication rate was 14% and included hemorrhage from the graft requiring return to the operating room (n = 4) and graft infection (n = 4). The late conduit-related complication rate was 15.8% and included graft infection (n = 1), graft thrombosis (n = 3), major amputation resulting from conduit failure (n = 1), pseudoaneurysm degeneration requiring repair (n = 2), graft hemorrhage (n = 1), and symptomatic graft stenosis (n = 1).

CONCLUSIONS

A cryopreserved arterial allograft is a useful alternative conduit for peripheral vascular reconstruction in infected or contaminated surgical fields when other autologous or prosthetic conduits are either unavailable or contraindicated. In the immediate postoperative period, these repairs demonstrate acceptable resistance to graft failure and reinfection, particularly in conjunction with adjunctive rotational muscle flap coverage. Late conduit-related complications appear to be infrequent.

Infrarenal Aortic Endograft Infection: A Single-Center Experience

PURPOSE:

Endograft infection is an infrequent but one of the most serious and challenging complications after endovascular aortic repair. The aim of this study was to assess the management of this complication in a tertiary center.

CASE SERIES:

A retrospective analysis of a prospective database was performed including all patients who underwent elective endovascular abdominal aortic repair (EVAR) from 2003 to 2016 in a tertiary center. Seven cases of endograft infection were identified during the follow-up period from a total of 473 (1.48%) EVAR. Most frequent symptoms at presentation were fever (71.4%) and lumbar pain (57.1%). One case developed an early infection, while 6 cases were diagnosed as late infections. Mean time from endograft placement to symptom presentation was 28.3 months (2-91.5 months). Gram-positive cocci were the microorganisms most commonly isolated in blood cultures (66%). Two cases were managed with endograft removal and aortic reconstruction with a cryopreserved allograft, 2 cases with surgical drainage, and 2 cases exclusively with antibiotic therapy. In 1 case, the diagnosis was performed postoperatively based on intraoperative findings associated with positive graft cultures; and graft explantation was performed with "in situ" reconstruction using a Dacron graft. Perioperative mortality was 42.9%. One-year mortality was 57.1%. Mean follow-up was 21.5 months.

CONCLUSION:

Endograft explantation is the gold standard of treatment; however, given the overall high morbi-mortality rates of this pathology, a tailored approach should always be offered depending on the patient's overall condition. Conservative management can be an acceptable option in those patients with short life expectancy and high surgical risk.

Organization model for allotransplantations of cryopreserved vascular grafts in Czech Republic

The transplantation of fresh or cryopreserved vascular allografts in patients with a prosthetic graft infection or critical limb ischemia is necessary for their limb salvage and, in many cases, represents a lifesaving procedure. While transplantation of fresh allografts has a long history in the Czech Republic, the standard use of cryopreserved vascular allografts was introduced into the clinical practice in 2011 as a result of the implementation of EU Directive 2004/23/EC into national legislation (Human Cell and Tissue Act No. 296/2008 Coll.). The authors present an organizational model based on cooperation between the majority of Czech Transplant Centers with a tissue establishment licensed by the national competent authority. In various points, we are addressing individual aspects of experimental and clinical studies which affect clinical practice. Based on experimental and clinical work, the first validation of cryopreserved arterial and venous grafts for clinical use was performed between 2011 and 2013. The growing number of centers participating in this programme led to a growing number of patients who underwent transplantation of vascular allografts. In 2015 the numbers of transplanted fresh versus cryopreserved allografts in the Czech Republic were almost equal. Cooperation of the participating centers in the Czech Republic with the licensed Tissue Establishment made it possible to achieve a full compliance with the European Union Directives, and harmonized national legal norms and assured a high quality of cryopreserved vascular allografts.

Cryopreserved Human Allografts for the Reconstruction of Aortic and Peripheral Prosthetic Graft Infection

Background: This study aimed to present cases with cryopreserved human allografts (CHAs) for vascular reconstruction in both aortic and peripheral infected prosthetic grafts.

Materials and Methods: This is a single center, observational descriptive study with retrospective analysis. In all cases, the infected prosthetic graft material was completely removed. At discharge, patients were administered anticoagulants. Follow-up examinations included clinical visits, echo-color-Doppler ultrasounds, or computed tomography angiography within 30 days and at 3, 6, and 12 months after the treatment, and then twice per year.

Results: We treated 21 patients (90% men, n=19) with the mean age of 71±12 years and mean interval between the initial operation and replacement with CHA of 30 months [range, 1–216; interquartile range (IQR), 2–36]. In-hospital mortality was 14% (n=3); no CHA-related complication led to death. Limb salvage was 100%. No patient was lost at the median follow-up of 14 months (range, 2–61; IQR, 6–39). No rupture, aneurysmal degeneration, or re-infection occurred. Estimated freedom from CHA-related adverse events (95% confidence interval, 43–63) was 95% at 3 years.

Conclusion: In our experience, CHAs are a viable option for prosthetic graft infections and provide satisfactory clinical results and favorable stability because of a very low rate of CHA-related adverse events during follow-up.

Recurrent Aortoenteric Fistula: Two Different Bridge Solutions

A “recurrent” aortoenteric fistula (AEF) is very rare and in literature anecdotic. Currently, graft excision and extra-anatomic bypass are considered the treatments of choice, but are associated with significant mortality and morbidity. Herein, we describe the case of a “recurrent” AEF treated before definitive extra-anatomic bypass, by two different, staged bridge solutions: allograft in situ replacement and endovascular grafting. At 1, 3 and 6-month follow-up, the patient was asymptomatic and normally active.

Use of cryopreserved cadaveric arterial allograft as a vascular conduit for peripheral arterial graft infection

Major peripheral arterial graft infection is a potentially devastating complication of vascular surgery, associated with significant mortality and high amputation rates. Autologous saphenous veins are considered optimal arterial conduits for lower extremity revascularization in infected fields, but they are often unavailable or unsuitable in these patients. This study describes two patients with major peripheral graft infection, but without available autologous veins, who underwent graft excision and cryopreserved cadaveric arterial allograft reconstruction. Although long-term graft durability is unclear because of gradual deterioration and degeneration, these findings suggest that cadaveric allografts may be good options for patients with major peripheral graft infection.

Fresh arterial homograft for bypass in critical limb ischaemia with infection

We present what we believe is Australia's first fresh peripheral arterial transplant for revascularisation of an ischaemic limb. Although cryopreserved homografts are accepted as a management option for revascularisation of critical limb ischaemia in infected fields, cryopreserved peripheral vascular tissue is not currently available in Australia. We describe a 72-year-old man without autologous conduit in whom infected prosthetic grafts were explanted, causing critical limb ischaemia of a below knee stump. Fresh peripheral arterial tissue was procured via the Australian organ donation authority, DonateLife, and was used to revascularise the stump with an axillofemoral bypass. This permitted successful healing of the stump within 6 weeks and mobilisation with a prosthesis. This case illustrates that fresh arterial homografts are a viable bridging solution for revascularisation of limb ischaemia with infection. However, it also highlights the need to establish a peripheral homograft bank so that cryopreserved conduits are readily available for similar scenarios.

How To Diagnose and Manage Infected Endografts after Endovascular Aneurysm Repair

The prevalence of endograft infections (EI) after endovascular abdominal aortic aneurysm repair is below 1%. With the growing number of patients with aortic endografts and the aging population, the number of patients with EI might also increase. The diagnosis is based on an association of clinical symptoms, imaging, and microbial cultures. Angio-computed tomography is currently the gold-standard technique for diagnosis. Low-grade infection sometimes requires nuclear medicine imaging to make a correct diagnosis. There is no good evidence to guide management so far. In the case of active gastrointestinal bleeding, pseudoaneurysm, or extensive perigraft purulence involving adjacent organs, an invasive treatment should always be attempted. In the other cases (the majority), when there is not an immediate danger to the patient's life, a conservative management is started with a proper antimicrobial therapy. Any infectious cavity can be percutaneously drained. Management depends on the patient's condition and a tailored approach should always be offered. In the case of a patient who is young, has a good life expectancy, or in whom there is absence of significant comorbidities, a surgical attempt can be proposed. Surgical techniques favor, in terms of mortality, patency, and reinfection rate, the in situ reconstruction. Choice of technique relies on the center and the operator's experience. Long-term antibiotic therapy is always required in all cases, with close monitoring of the C-reactive protein.

Infectious aortitis in a liver transplant recipient

The development of an abdominal aortic aneurysm secondary to infectious aortitis following solid organ transplantation is a rare event that in the absence of surgical intervention, can lead to uncontrolled sepsis, catastrophic hemorrhage and death. Arterial allografts have been a viable surgical option for the past 30 years, although operative modalities have undergone a paradigm shift in recent years. We describe the first case in the literature of a liver transplant recipient who developed an infrarenal aortic aneurysm secondary to Salmonella bacteraemia, which was treated successfully with aortic allograft transplantation.

Acute regeneration and chronic acellular transformation of rabbit cryopreserved aortic allografts

An analysis of rabbit cryopreserved aortic allografts excised on postoperative days (POD) 2, 5, 11, 60, 210, 360, and 720, as well as controls that were untransplanted native aortas and cryopreserved aortas, was performed. On POD2, the number of medial smooth muscle cells in the allografts was reduced to approximately 50%. Ki-67 analysis revealed that medial smooth muscle cells in the allografts proliferated from the 2nd day. By the 11th day, their proliferation ceased and the number of medial smooth muscle cells was restored to almost at the same level as in the controls. Polymorphic microsatellite DNA marker analysis disclosed that the restored medial smooth muscle cells were of donor origin. From 7 months through 2 years, the media of cryopreserved aortic allografts were transformed into acellular structures, in which the elastic fibers were preserved. On the other hand, newly accumulated smooth muscle cells were observed in the adventitia just outside of acellular media after 7 months. In some cases, scattered lamellar calcium deposition was observed in the same regions. This study presents a comprehensive documentation of regeneration and acellular transformation in cryopreserved aortic allografts based on short and long-term analysis.

Management of vascular graft and endoprosthetic infection of the thoracic and thoraco-abdominal aorta

Infection of a vascular prosthesis or endovascular stent-graft is probably the most serious complication that may occur after implantation and dramatically affects the patient's outcome. Surgical treatment is almost always required but even after surgery, morbidity can be significant. Several approaches have been described with some advantages and/or some limitations. Complete resection of the infected foreign material with debridement of the surrounding tissue gives most probably the better results. Orthotopic reconstruction is the best option for all thoracic and thoraco-abdominal pathologies and the use of coated prostheses, homografts or self-made vascular tubes from xenopericardial tissue has to be discussed from case to case. In some exceptional situations, endovascular stent-graft can be performed as bridging to a more complete treatment if general condition of the patient has to be stabilized.

Transplantation of a fresh cadaveric iliac homograft after celiac artery aneurysmectomy

The authors describe a case of a 34-year-old woman who presented to the ER with acute epigastric pain caused by an 8-cm celiac artery aneurysm. The patient underwent total aneurysmectomy, distal splenopancreasectomy, and reconstruction of the hepatic arterial inflow using a fresh cadaveric iliac artery homograft. The patient was discharged home on postoperative day 8 in good clinical condition. After 60 months of follow-up, the patient is well and with a patent vascular homograft. The use of a fresh cadaveric iliac homograft described here may represent an option in young patients with low operative risk undergoing visceral artery aneurysm repair.

The seven-year' secondary patency of a fresh arterial allograft in the femorocrural position in a heart transplant recipient

Critical limb ischemia in patients with diabetes at the organ complication stage represents a considerable challenge in vascular medicine. Because of the complexity of the disease and the often symmetric involvement of both lower limbs, a discrepancy between suitable vascular conduit availability and the actual requirement can occur: notably, the prevalence of multilevel and diffuse arterial disease often limits the possibilities of endovascular treatment, and, in surgical cases, frequently prohibits the effective use of prosthetic material. In our patient with bilateral critical limb ischemia and previous coronary artery bypass graft followed by cardiac transplantation, only one great saphenous vein remained available. That was used in its entirety to salvage one limb as a sequential femorocrural bypass. A similar surgical procedure with a fresh arterial allograft retrieved from a deceased donor was performed on the other extremity . ABO compatibility as well as the chronic immunosuppressive therapy in a heart transplant recipient may have contributed to the favorable long-term clinical outcome of the allogeneic arterial reconstruction.

Arterial Allograft Allows In-line Reconstruction of Prosthetic Graft Infection with Low Recurrence Rate and Mortality

Surgical management of infected prosthetic vascular grafts is associated with a significant risk of recurrent infection, limb loss, and mortality. Treatment options include graft excision with extra-anatomic bypass and in-line repair with prosthetic graft, vein, or artery. We hypothesized that inline reconstruction using cryopreserved arterial allografts would be associated with a lower recurrent infection rate, limb loss, and mortality than other alternatives. We reviewed all cases where adults underwent surgical management of infected prosthetic aortic, iliac, or femoral bypass grafts with cryopreserved arterial allograft at our medical center from 2001 to 2008. Cryopreserved arterial allografts were used in 21 patients. There were nearly equal number of men (n = 11, 52%) and women (n = 10, 48%). The median age was 63 years and median time since cryoartery repair was 4 years. There have been no deaths in the follow-up period. Complications (19%) included colon perforation (n = 1), lower extremity compartment syndrome (n = 1), limb ischemia (n = 1), and reinfection with pseudoaneurysm and subsequent limb amputation (n = 1). These positive findings of low morbidity and absence of mortality in high risk patients have resulted in a shift at our institution to the preferential use of cryopreserved arterial allograft with in-line reconstruction for infected prosthetic grafts.

Successful surgical treatment of multilevel aortic aneurysms combined with renal transplantation

The concomitant presence of a thoracic aortic aneurysm and an abdominal aortic aneurysm in patients considered for renal transplantation is extremely rare. To our knowledge, this is the first case report of the successful treatment of multilevel aortic aneurysms together with renal transplantation. The treatment modalities in renal transplant patients with concomitant aortic aneurysms are discussed.

Use of Cryopreserved Femoral Vein for In Situ Replacement of Infected Femorofemoral Prosthetic Artery Bypass

Isolated groin infection following crossover femoral bypass is not uncommon, and its management may be challenging, especially in medically high-risk patients. When an in situ replacement is appropriate, using an autologous vein (femoral or saphenous) would be the preferred method; however, this may not always be feasible. The authors used cryopreserved femoral vein grafts for in situ replacement of femorofemoral bypass grafts with excellent results in 3 high-risk patients who developed early graft infections and failed graft preservation attempts. In situ replacement of infected femorofemoral grafts using a cryopreserved femoral vein graft can be considered as a second-line intervention when an adequately sized autologous vein is unavailable or unusable or is not feasible in high-risk patients.

Surgical strategy in aortoesophageal fistulae: endovascular stentgrafts and in situ repair of the aorta with cryopreserved homografts

OBJECTIVE

The surgical treatment of aortoesophageal fistulae (AEF) has a high morbidity and mortality rate. We report our experience with the sequential use of endovascular thoracic stentgrafts and cryopreserved aortic homografts for in situ repair of the descending thoracic aorta.

METHODS

In a 7-year period, 6 patients with AEF were treated at our center. After primary endovascular repair in all cases, 4 patients subsequently underwent in situ repair of the descending thoracic aorta with cryopreserved homografts. Long-term antibiotic therapy was given in all cases. Recent clinical status and radiologic findings on follow-up studies of each patient were analyzed. The mean follow-up time was 35 months (range, 2-76).

RESULTS

Endovascular stentgraft repair was technically successful in all cases. Two patients were not candidates for open surgical repair because of their medical condition; they both died within 8 weeks after discharge from the hospital, 1 from recurrent septic episodes, and the other from upper gastrointestinal bleeding. One of 4 patients who had undergone open surgical repair died 1 year later from upper gastrointestinal bleeding that occurred presumably due to an infectious degeneration of the homograft after secondary infection with a methacillin-resistant Staphyloccocus aureus. In 1 case persistent paraplegia and in another case persistent renal failure occurred.

CONCLUSION

The use of cryopreserved homografts is a valuable alternative to in situ repair with prosthetic vascular grafts or extra-anatomic reconstructions in the surgical treatment of AEF. Endovascular stentgraft placement plays a role as a bridging procedure in emergency situations.

Amikacin-loaded vascular prosthesis as an effective drug carrier

Strong covalent immobilization of amikacin on Uni-Graft((R)) DV straight vascular prostheses made of gelatine-sealed poly(ethylene terephthalate) fibres was performed according to procedure described in the Polish Patent No. P-358934. The concentrations of amikacin in sample solutions were estimated either by HPLC or by UV spectroscopy method previously optimized for amikacin measurements. A high correlation was found between these two methods. It was found that the antibiotic was bound in mixed-type way via three types of interactions: strong covalent bonds (dominating amount: 81.84%) and weak interactions: physical adsorption and ionic bonds (18.19%). Even when total amount of physically and ionically attached drug has been released, the remaining covalently bound amount still locally protected the prostheses in vitro against bacteria. The release test was conducted in PBS at pH 7.4 at 37 degrees C and showed that about 15% of total drug amount was eluted from the matrix during the first 7 days of shaking, then no more antibiotic was released. It suggested that about 85% of amikacin attached to prosthesis modified in mixed-type mode was bound via covalent interactions. A bacterial inhibition test on Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 showed inhibition of growth for all strains at low inoculum concentrations up to 30 days as well as high inoculum concentration for E. coli. At high concentrations of S. aureus and P. aeruginosa, the modified prostheses showed slight bacteriostatic effect since 10th day of experiment. Amikacin-modified vascular prostheses might therefore be protected against bacterial infection locally, without long-lasting drug release to human system.

Endothelial cell fatty acid unsaturation mediates cold-induced oxidative stress

Ultraprofound hypothermia (< 5 degrees C) induces changes to cell membranes such as liquid-to-gel lipid transitions and oxidative stress that have a negative effect on membrane function and cell survival. We hypothesized that fatty acid substitution of endothelial cell lipids and alterations in their unsaturation would modify cell survival at 0 degrees C, a temperature commonly used during storage and transportation of isolated cells or tissues and organs used in transplantation. Confluent bovine aortic endothelial cells were treated with 18-carbon fatty acids (C18:0, C18:1n-9, C18:2n-6, or C18:3n-3), C20:5n-3 or C22:6n-3 (DHA), and then stored at 0 degrees C without fatty acid supplements. Storage of control cells caused the release of lactate dehydrogenase (LDH) and a threefold increase in lipid peroxidation (LPO) when compared to control cells not exposed to cold. Pre-treating cells with C18:0 decreased the unsaturation of cell lipids and reduced LDH release at 0 degrees C by 50%, but all mono- or poly-unsaturated fatty acids increased injury in a concentration-dependent manner and as the extent of fatty acid unsaturation increased. DHA-treatment increased cell fatty acid unsaturation and caused maximal injury at 0 degrees C, which was prevented by lipophilic antioxidants BHT or vitamin E, the iron chelator deferoxamine, and to a lesser extent by vitamin C. Furthermore, the cold-induced increase in LPO was reduced by C18:0, vitamin E, or DFO but enhanced by DHA. In conclusion, the findings implicate iron catalyzed free radicals and LPO as a predominant mechanism of endothelial cell injury at 0 degrees C, which may be reduced by increasing lipid saturation or treating cells with antioxidants.

Fresh Arterial Grafts as Conduits for Vascular Reconstructions in Transplanted Patients

OBJECTIVES

To assess the outcome of arterial allografts in patients receiving organ transplantation.

DESIGN

From October 1997 to June 2005, we used fresh arterial allografts as vascular conduits in 21 patients for the treatment of claudications (10), abdominal aortic aneurysm (6), complicated renal transplantation (2), acute lower extremity ischemia (2) and gangrene (1). At the time of the vascular procedure, ten of the patients (Group A) had already undergone organ transplantation. The mean follow up period was 32 months for renal and 37 months for heart recipients, respectively. In 11 patients (Group B), the vascular reconstruction was undertaken simultaneously with the renal transplantation. The mean follow up period was 49 months.

RESULTS

There was no arterial allograft related deaths. No signs of arterial graft infection or requirement for secondary intervention (angioplasty and/or thrombolysis) were observed during the follow up period.

CONCLUSIONS

Our experience suggests that it is possible to use fresh arterial allografts in the treatment of arterial occlusive disease or abdominal aortic aneurysm, both in already transplanted patients and simultaneously with organ transplantation, with good results.

Redo total aortic arch replacement using an extended homograft for graft infection

A 65-year-old man developed graft infection 3 years after total aortic arch replacement for a chronic dissecting aneurysm. Redo total aortic arch replacement was performed using an extended homograft following 2 days of open drainage of the mediastinum. The patient has been free from a recurrent mediastinitis over the last 3 years.

Evolution from axillofemoral to in situ prosthetic reconstruction for the treatment of aortic graft infections at a single center

OBJECTIVE

The primary purpose of this study was to analyze the clinical outcome in patients treated for aortic graft infections with in situ reconstruction (ISR). As a secondary aim, the outcomes were compared between patients who had similar clinical characteristics and extent of infection, needed total graft excision, and had either ISR or axillofemoral reconstruction (AXFR).

METHODS

117 consecutive patients treated for aortic graft infection over a 20 year period from January 1981 to December 2001 were identified. 52 patients had prosthetic ISR, 49 had AXFR, and 16 had other reconstructions. The ISR patients treated with total (n = 35) or partial (n = 17) graft excision comprised the primary analysis. A second analysis was done between 34 ISR and 43 AXFR patients (non-concurrent groups), as stated above. Primary outcome measures were early and late procedure-related death, primary graft patency and limb loss. Secondary outcomes were operative morbidity, patient survival, and graft reinfection rates.

RESULTS

There were 40 males and 12 females with a mean age of 69 years treated with ISR. 43 patients had Rifampin-soaked grafts and 39 had omental flap or other autogenous coverage. Operative morbidity occurred in 23 patients (44%). There were 4 early and no late procedure-related deaths after a median follow up of 3.4 years (range, 2 months to 9.6 years). Primary patency and limb salvage rates at 5 years were 89% and 100%, respectively. Graft reinfection occurred in 6 patients (11.5%) and was not associated with procedure-related death. In the comparative analysis, the procedure-related death rate for patients treated with ISR was not different than those treated with AXFR (9% versus 23%; P = 0.11). There was a significant improvement in primary patency between ISR and AXFR at 5 years (89% versus 48%; P = .01). Limb salvage was 100% for ISR and 89% for AXFR at 5 years (P = .06). The incidence of graft reinfection was similar in both groups: 11% for ISR and 17% for AXFR (P = .28). Major complications or procedure-related deaths occurred in 12 patients after ISR (30%) and 26 patients (60%) after AXFR (P < .04).

CONCLUSION

ISR is a safe and effective alternative in the treatment of select patients with aortic graft infection. Graft reinfection occurred in 11.5% of the patients. The graft patency and limb salvages rates are excellent.

Limitations in the management of aortic graft infections

The use of aortic allografts has emerged as a management option in patients with aortic graft infections. We present a patient with a history of Takayasu's disease whose aortic graft infection was controlled with replacement of the excised infected aortic graft with an allograft. However, the patient died 9 months later after the rupture of a large anastomotic aortic aneurysm. Our report emphasizes the limitations in the management of aortic graft infections in patients with extensive vascular disease such as Takayasu's disease. This is the result of difficulties in performing extra-anatomical bypass as well as a possibly increased risk of formation of anastomotic aneurysms in these patients.

The Structural and Cellular Viability in Cryopreserved Rabbit Carotid Arteries

OBJECTIVE

We investigated the histological and mechanical changes in addition to viable cellular recovery in cryopreserved blood vessels.

MATERIALS AND METHODS

Rabbit carotids were cryopreserved in a cryoprotective medium containing 1.5 M of 1,2-propanediol (PD) and then were thawed slowly in an ice bag that had been precooled in liquid nitrogen. Fresh carotids were used as the control. The fresh and freeze-thawed arteries were cultured for the growth of vascular smooth muscle cells (VSMCs). The freeze-thawed arterial tissues were perfused in vitro for 6, 12, or 24 h, respectively, to assess the integrity of carotid walls and the mechanical properties.

RESULTS

The results showed that it took almost the same time (24 approximately 36 h) for the VSMCs of the PD-cryopreserved arteries to regenerate as those from the fresh arteries. Their growing speeds also were similar. On the contrary, Me2SO-cryopreserved (1.5 M) arteries were unable to regenerate VSMCs in culture. After freeze-thawing, the mechanical properties decreased significantly (P < 0.003 for elastic modulus and P < 0.001 for fracture strength). After in vitro perfusion of the freeze-thawed carotid arteries, all of the survived endothelial cells fell off, and some of the VSMCs denaturalized or necrosed. The internal elastic fibers and collagen showed various degrees of cracking. The mechanical properties were decreased (P < 0.05).

CONCLUSION

Our findings demonstrate that the PD-containing cryoprotective medium can preserve regenerative capacity of VSMCs, which makes it a useful technique for viable VSMC recovery. However, the freeze-thawing process and the in vitro perfusion caused serious disruption in the arterial mechanical properties, rendering the cryopreserved blood vessels less useful for vessel reconstruction.

Cryopreserved Arterial Allografts in the Treatment of Prosthetic Graft Infections

AIM

The purpose of this study was to evaluate the effectiveness of cryopreserved arterial allografts in the management of prosthetic graft infection.

MATERIAL AND METHODS

Over a 5-year period 45 patients with infection of prosthetic vascular grafts were treated. There were 39 intra-abdominal infected grafts (group I) and six extra-abdominal infected grafts (group II). Treatment consisted of total graft removal and in situ or extra-anatomic implantation of cryopreserved arterial allografts. Six patients were operated on as an emergency. Four patients presented with aorto-enteric fistula. Follow-up ranged from 30 to 78 months.

RESULTS

There were six in-hospital deaths and two additional patient deaths during follow-up, yielding an overall mortality rate of 18%. Six patients died due to complications directly related to infection or insertion of an allograft. Combined short and long-term mortality rate was much higher in patients operated on as an emergency (67%) compared to elective cases (11%). Patients with aorto-enteric fistula had the highest mortality rate (75%). Primary and secondary 3-year allograft patency rates for group I were 84 and 94%, respectively and for group II were 60 and 80%, respectively.

CONCLUSIONS

Aortic allografts are useful in the treatment of infection of major vascular prosthetic grafts, except for patients with aorto-enteric fistula. Patients with infection of the prosthetic graft should be promptly assessed for graft removal, since results of elective surgery are much better than results of emergency procedures.