Experience with cryopreserved arterial allografts in the treatment of prosthetic graft infections

Vascular allografts for clinical application in Europe: assessment of 30 years of experience with vascular tissue banking in Brussels

Vascular tissue banking has been carried out in Brussels for over 30 years in compliance with EU and Swiss tissue banking regulations. A total of 2.765 vascular tissue donations were performed in Belgian, French, Netherlands and Suisse transplant centres: 547(20%), 1.013(37%) and 1.205(43%) during the first, second and third periods, respectively. 85% and 18% increase in donations during the second and third decades compared to previous one, were remarkable. Of the 7.066 evaluated vascular tissues, 2.407(227, 921 and 1.259) were discarded (34.1%), whereas 4.659(523, 1.861 and 2.275) accepted (65.9%) during the respective period. Of the 92 donated veins, 44(47.8%) were discarded and 48(52.2%) accepted. Allografts available for clinical application were stored in vapours of liquid nitrogen. A total of 4.636 allografts were delivered and transplanted for cases of infection (58%), critical limb ischaemia (16%) and congenital cardiac surgery (15%). Thirty veins were implanted. The progressive increases in donations of 20%, 37% and 43% and in transplantations of 20.8%, 34.6% and 45% during the first, second and third periods, respectively, were remarkable. Complications were reported after transplantation and these included acute rejection of two femoral arteries one month after transplantation. We conclude that the donation and transplantation of cryopreserved vascular allografts was stable with a progressive increase over time. Allografts were used predominantly for the treatment of infection, limb salvage for critical ischaemia and for neonates and infants with congenital cardiac malformation. Immune related rejection was observed. This should be a subject of future investigation.

Obturator bypass remains a useful option

OBJECTIVES

The femoral tripod remains technically crucial in vascular surgery, as well for an elective revascularization as for an extensive approach to the arterial tree. The management of septic complications and healing disorders in this area is really challenging. Obturator bypass (OB) represents an alternative sometimes employed in this context, but few recent series were recently published. The objectives of this work were thus to evaluate the results of OB in terms of patency, morbi-mortality, healing evolution and absence of reinfection.

MATERIAL AND METHODS

This was a monocentric retrospective study including all the patients treated by OB, whatever the cause, between January 2010 and December 2020. Primary outcomes were the primary and the secondary patencies. The secondary outcomes were the morbi-mortality, freedom from infection and healing.

RESULTS

During this period, 23 OBs were carried out in 22 patients, with a majority of men (77%) whose median age was 70 years [34 - 87]. The indications were infection in 19 patients (86%), and iterative thrombosis in three patients (14%). The substitute was an arterial allograft in 82% of the cases, and the outflow was the deep femoral artery only in 14% of the cases. The median operative time was 224 min [111-391] and median blood losses were 900 mL [300-3900]. We observed seven systemic (32%), and eight local complications (36%). Healing was obtained in 90% of the cases, and freedom from infection was obtained in 100% of the cases. The median duration of follow-up was 594 days [5 - 2517]. One-year, two-year and three-year primary patency rates were 84%, 78%, and 63%, respectively. One-year, two-year and three-year secondary patencies were 94%, 94%, and 80%, respectively. One-month, one-year, two-year and three-year survival rates were 86%, 73%, 67%, and 53%, respectively.

CONCLUSION

Our study showed that the OB represents a relevant alternative in the event of complex lesions of the femoral tripod, with good patency and healing rates and good infection control. On the other hand, its consequences in terms of morbi-mortality confirm that OB is a major surgery that should be used when a traditional approach is not possible.

Results of the Proliferative Activity’s Analysis of Bifidobacterium Exometabolites in Regard to Hospital Isolates from Patients after Vascular Synthetic Prosthetics Implantation

Problems ofdevelopment of purulent septic complications in vascular surgery during the usage of synthetic prosthetics for shunting and arterial prosthetics are described in this work.Leading factors of development of prosthetic infection are described. Specialties of diagnostics and bacteriological researches wound discharge of wound’s discharge are shown. Tactics of complex treatment of patients with prosthetic infection are presented. This work is dedicated to the experimental researchof proliferative activityof the most encountered opportunistic microorganisms found from the patients of vascular surgery profile with purulent septical complications under the influence of bifidobacteriumbifidium’sexometabolites. Presented results proof the submission of proliferative activity of the most widespread antibiotic-resistant hospital’s isolates under the influence of bifidobacteriumbifidium’sexometabolites.Evaluation during the experiment in vitro of the influence of bifidobacteriumbifidium’sexometabolites on proliferative activityof opportunistic microorganisms.

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.

Medical treatment of prosthetic vascular graft infections: Review of the literature and proposals of a Working Group

More than 400000 vascular grafts are inserted annually in the USA. Graft insertion is complicated by infection in 0.5-4% of cases. Vascular graft infections (VGIs) are becoming one of the most frequent prosthesis-related infections and are associated with considerable mortality, ranging from 10 to 25% within 30 days following the diagnosis. Treatment of VGI is based on urgent surgical removal of the infected graft followed by prolonged antibiotherapy. Data regarding the best antibiotherapy to use are lacking since no well designed trial to study antimicrobial treatment of VGI exists. Moreover, since VGIs demonstrate very specific pathophysiology, guidelines on other material-related infections or infective endocarditis treatment cannot be entirely applied to VGI. A French multidisciplinary group gathering infectious diseases specialists, anaesthesiologists, intensivists, microbiologists, radiologists and vascular surgeons was created to review the literature dealing with VGI and to make some proposals regarding empirical and documented antibiotic therapy for these infections. This article reveals these proposals.

Prevention and treatment of aortic graft infection

Prosthetic vascular graft infection remains one of the most challenging surgical problems for vascular surgeons. This condition is classically associated with high morbidity and mortality rates. Accurate diagnosis of a vascular graft infection can typically be made based on a thorough history and physical examination; although, infrequently, an extensive radiological evaluation is necessary to establish the clinical finding. Complete graft excision and extra-anatomic bypass grafting remains a commonly accepted surgical treatment strategy. Recent clinical data have supported other treatment modalities, including the use of in situ antibiotic-impregnated graft replacement, in situ allograft replacement and in situ autologous graft replacement. This article will review the pathobiology of aortic graft infection, as well as methods to prevent a prosthetic graft infection. Furthermore, various surgical treatment modalities of aortic graft infection will be discussed.

Preclinical evaluation of ice-free cryopreserved arteries: structural integrity and hemocompatibility

OBJECTIVE

Arterial allografts are routinely employed for reconstruction of infected prosthetic grafts. Usually, banked cryopreserved arteries are used; however, existing conventional freezing cryopreservation techniques applied to arteries are expensive. In contrast, a new ice-free cryopreservation technique results in processing, storage and shipping methods that are technically simpler and potentially less costly. The objective of this study was to determine whether or not ice-free cryopreservation causes tissue changes that might preclude clinical use.

METHODS

Conventionally frozen cryopreserved porcine arteries were compared with ice-free cryopreserved arteries and untreated fresh controls using morphological (light, scanning electron and laser scanning microscopy), viability (alamarBlue assay) and hemocompatibility methods (blood cell adhesion, thrombin/antithrombin-III-complex, polymorphonuclear neutrophil-elastase, β-thromboglobulin and terminal complement complex SC5b-9).

RESULTS

No statistically significant structural or hemocompatibility differences between ice-free cryopreserved and frozen tissues were detectable. There were no quantitative differences observed for either autofluorescence (elastin) or second harmonic generation (collagen) measured by laser scanning microscopy. Cell viability in ice-free cryopreserved arteries was significantly reduced compared to fresh and frozen tissues (p < 0.05).

CONCLUSIONS

The formation of ice in aortic artery preservation did not make a difference in histology, structure or thrombogenicity, but significantly increased viability compared with a preservation method that precludes ice formation. Reduced cell viability should not reduce in vivo performance. Therefore, ice-free cryopreservation is a potentially safe and cost-effective technique for the cryopreservation of blood vessel allografts.

Decontamination of heart valve and arterial allografts in the European Homograft Bank (EHB): comparison of two different antibiotic cocktails in low temperature conditions

The aim of the study was to compare the efficiency of two different antibiotic cocktails in the cardiovascular allograft decontamination. Low temperature, low-concentration antibiotic cocktail with Cefoxitin, Lincomycin, Polymixin B and Vancomycin was decontamination protocol in EHB for many years. The modified cocktail doesn't contain Cefoxitin. The study had two steps. First step: cardiovascular allografts from 80 donors are incubated in classical (group 1) or modified cocktail (group 2). Second step: 184 and 182 allografts of group 1 and group 2 are incubated in the modified and classical antibiotic cocktail, respectively. The bacteriological examination is performed in three steps: A-transport solution, B-decontamination solution and C-cryopreservation solution. During the first step 23.75% of the tissues were initially contaminated mainly with Staphylococcus (78.95%). 93.75% of the allografts of group 1 and 100% of group 2 were sterile after incubation (p = 0.058). 25.54% and 30.77% of group 1 and 2, respectively were contaminated in A-examination during the second step. Staphylococci were isolated in 82.98% and 69.64% in group 1 and 2, respectively. About 4.35% of group 1 and 5.5% of group 2 were contaminated in A, B, and C whereas 5.4% of group 1 and 4.4% of group 2 were contaminated in B or C after being sterile in A. Finally 9.78% of the tissues were rejected and 90.22% cryopreserved in the modified, whereas 9.89% rejected and 90.11% accepted in the classical group (p = 0.1). The difference was non-significant in the level of decontamination between the two cocktails. Contamination of some tissues with low growing, low-pathogen germs that appeared in B or C examination, couldn't be explained. This issue needs complementary investigation.

Patency and structural changes in cryopreserved arterial grafts used as vessel substitutes in the rat

OBJECTIVE

To evaluate the patency and structural changes that occur in the short- and mid-term when cryopreserved syngenic arterial grafts are implanted in an experimental animal model.

MATERIAL AND METHODS

Segments of iliac artery from the Spraque-Dawley rat were cryopreserved in a biological freezer according a controlled, computerized freezing protocol whereby the specimens are cooled at a rate of 1 degrees C/min. After storage at -145 degrees C in liquid N2 vapor for 30 days, the cryografts were slowly thawed. These vessels were grafted to the common iliac artery in syngenic animals. The following study groups were established: group I (GI), non-implanted cryografts; group II (GII), autografts; and group III (GIII), cryoisografts. The control group (CG) was comprised of fresh iliac arteries. The animals were sacrificed 14, 30, or 90 days post-surgery. At each of these follow-up times, graft specimens were morphologically evaluated by light and scanning and transmission electron microscopy and immunolabeling of endothelial cells (vWf). Cell damage attributed to the cryopreservation or grafting process was also determined.

RESULTS

At the time of sacrifice, graft patency was 100% for the autografts, while 26.6% of the cryoisografts showed fully occlusive thrombosis. Among other complications, two pseudoaneurysms were detected. After cryopreservation, the grafts (GI) showed patches of endothelial denudation and good cellularity of the medial layer. The intimal hyperplasia observed in autografts implanted for 14 days (GII) was significantly delayed until day 30 when the graft was cryopreserved (GIII). Cryoisografts showed general thinning of the arterial wall and degeneration accompanied by medial layer cell loss. These grafts showed most cell damage at 90 days post-implant. Expression of the vWf in all specimens showing intimal hyperplasia was confined to the outermost graft layer.

CONCLUSIONS

Cryopreservation modified the reparative response of the grafts. Owing to faster degeneration of the medial layer and a delay in the appearance of intimal hyperplasia, arterial wall thickness was reduced relative to that of the non-cryopreserved autografts. This thinning, at least in the short-term (90 days), does not seem to give rise to aneurysms owing to the generation of a neointima that stabilizes the vessel wall.

Cryopreserved arterial allograft reconstruction for peripheral graft infection

OBJECTIVE

This prospective, observational study evaluated the safety and efficacy of cryopreserved arterial allograft reconstruction in the management of major peripheral arterial graft infections.

METHODS

From April 1996 to May 2003, data from patients with major peripheral arterial graft infection who underwent graft excision and cryopreserved arterial allograft reconstruction were prospectively collected. Arterial allografts were harvested from multiple organ donors and cryopreserved at -80 degrees C. The patients were observed for survival, limb salvage, persistence or recurrence of infection, and allograft patency. The results were calculated with the Kaplan-Meier method.

RESULTS

During the 7-year study period, 17 patients (14 men, 3 women; mean age, 68 years) with major peripheral graft infection underwent graft excision and cryopreserved arterial allograft reconstruction. Eight patients (47%) had systemic sepsis, 5 (29%) had acute ischemia at the time of the allograft reconstruction, and 9 (53%) had experienced anastomotic rupture. Allograft reconstruction was performed as an emergency procedure in 7 patients (41%). There were no perioperative deaths or early amputations. Two patients had allograft ruptures in the groin during the early postoperative period. The mean follow-up period was 34 months (range, 8 to 80 months). There was no persistent or recurrent infection, and none of the patients received long-term (>3 months) antibiotic therapy. Reoperation for allograft revision, excision, or replacement was performed in 2 patients. The 18-month primary and secondary allograft patency rates were 68% and 86%; the overall limb salvage rate was 82% at 2 years.

CONCLUSION

Our experience with cryopreserved arterial allograft in the management of major peripheral bypass graft infection suggests that this technique seems to be a useful option for treating one of the most dreaded vascular complications.

Cryopreserved arterial allografts for in situ reconstruction of infected arterial vessels

OBJECTIVE

To review our experience of using cryopreserved allografts for in situ reconstruction in the presence of infection involving the aorta, iliac or femoral arteries.

DESIGN

Retrospective clinical study.

METHODS

From 3/2000 to 8/2003 all patients with mycotic aneurysms or secondary infection following earlier prosthetic replacement were treated with cryopreserved human allografts. Forty-two patients, 39 (93%) with a prosthetic graft infection and 3 (7%) with a mycotic aneurysm of the abdominal aorta were treated. Six (14%) had aorto-enteric fistulas, 5 (12%) had ruptured aneurysms, and 2 also had vertebral destruction. The median follow-up time was 20 months (range 1-42 months).

RESULTS

Thirty-day mortality was 14%. Three patients died due to multi-organ failure, two patients died from hypovolaemic shock due to allograft rupture and one from rupture of the native aorta. The overall mortality was 24% (four additional patients). Graft patency was 100% at 30 days and 97% at follow up in the survivors. The mean actuarial survival time was 32 months (95% CI=27-37 months).

CONCLUSIONS

Cryopreserved allografts for the in situ reconstruction of infected arteries or grafts have acceptable intermediate results.

Allograft replacement for infrarenal aortic graft infection: early and late results in 179 patients

OBJECTIVES

We evaluated early and late results of allograft replacement to treat infrarenal aortic graft infection in a large number of patients and compared the results in patients who received fresh allografts versus patients who received cryopreserved allografts.

METHODS

From 1988 to 2002 we operated on 179 consecutive patients (mean age, 64.6 +/- 9.0 years; 88.8% men). One hundred twenty-five patients (69.8%) had primary graft infections, and 54 patients (30.2%) had secondary aortoenteric fistulas (AEFs). Fresh allografts were used in 111 patients (62.0%) until 1996, and cryopreserved allografts were used in 68 patients (38.0%) thereafter.

RESULTS

Early postoperative mortality was 20.1% (36 patients), including four (2.2%) allograft-related deaths from rupture of the allograft (recurrent AEF, n = 3), all in patients with fresh allografts. Thirty-two deaths were not allograft related. Significant risk factors for early mortality were septic shock (P <.001), presence of AEF (P =.04), emergency operation (P =.003), emergency allograft replacement (P =.0075), surgical complication (P =.003) or medical complication (P <.0001), and need for repeat operation (P =.04). There were five (2.8%) nonlethal allograft complications (rupture, n = 2; thromboses, which were successfully treated at repeat operation, n = 2; and amputation, n = 1), all in patients with fresh allografts. Four patients (2.2%) were lost to follow-up. Mean follow-up was 46.0 +/- 42.1 months (range, 1-148 months). Late mortality was 25.9% (37 patients). There were three (2.1%) allograft-related late deaths from rupture of the allograft, at 9, 10, and 27 months, respectively, all in patients with fresh allografts. Actuarial survival was 73.2% +/- 6.8% at 1 year, 55.0% +/- 8.8% at 5 years, and 49.4% +/- 9.6% at 7 years. Late nonlethal aortic events occurred in 10 patients (7.2%; occlusion, n = 4; dilatation < 4 cm, n = 5; aneurysm, n = 1), at a mean of 28.3 +/- 28.2 months, all but two in patients with fresh allografts. The only significant risk factor for late aortic events was use of an allograft obtained from the descending thoracic aorta (P =.03). Actuarial freedom from late aortic events was 96.6% +/- 3.4% at 1 year, 89.3% +/- 6.6% at 3 years, and 89.3% +/- 6.6% at 5 years. There were 63 late, mostly occlusive, iliofemoral events, which occurred at a mean of 34.9 +/- 33.7 months in 38 patients (26.6%), 28 of whom (73.7%) had received fresh allografts. The only significant risk factor for late iliofemoral events was use of fresh allografts versus cryopreserved allografts (P =.03). Actuarial freedom from late iliofemoral events was 84.6% +/- 7.0% at 1 year, 72.5% +/- 9.0% at 3 years, and 66.4% +/- 10.2% at 5 years.

CONCLUSIONS

Early and long-term results of allograft replacement are at least similar to those of other methods to manage infrarenal aortic graft infections. Rare specific complications include early or late allograft rupture and late aortic dilatation. The more frequent late iliofemoral complications may be easily managed through the groin. These complications are significantly reduced by using cryopreserved allografts rather than fresh allografts and by not using allografts obtained from the descending thoracic aorta.

[Long-term evolution of a thoraco-abdominal cryopreserved arterial allograft]

We report a case of thoraco-abdominal pseudo-coarctation which developed late after implantation of a cryopreserved arterial allograft. The allograft was placed in a thoraco-abdominal position to treat an aorto-esophageal fistula after colonic esophagoplasty. Follow-up was free of complications for eight Years. The pseudo-coarctation was discovered during the evaluation of hypertension. Surgical treatment involved transdiaphragmatic bypass between the thoracic and infra-renal abdominal aorta. Arterial pressure immediately returned to normal. Twelve Months later, the patient is alive and well with normal blood pressure. A review of the literature revealed rare cases of arterial allograft with a description of the long-term outcome.

Use of the superior pedicled rectus abdominis flap to cover infected aortic grafts

Replacement of aortic aneurysms by a prosthetic graft is a common procedure in vascular surgery. Although success is generally achieved, infection or fistula may occur. Prosthetic graft infection has been reported in between one and six percent in most large series and is one of the most dreaded complications of abdominal aorta surgery. Dissatisfaction with extraanatomic procedures has led to the development of techniques of in situ replacement by allogenic material. However, adequate debridement and coverage of the aortic graft is necessary. To our knowledge, this is the first report of the use of a rectus abdominis muscle flap to cover an aortic allograft when other reconstructive options were impossible.

Ten-year experience in autogenous reconstruction with the femoral vein in the treatment of aortofemoral prosthetic infection

OBJECTIVE

to study the short and long term effectiveness of in situ replacement of infected aortic grafts with the lower extremity deep veins.

METHODS

forty-nine patients operated on for infrarenal aortic graft infection since 1990 were studied. Diagnosis of infection was based on clinical signs, bacteriological tests and typical findings on CT scan and leukocyte scan. The surgical treatment consisted in harvesting the femoral vein, total graft excision, thorough debridement and in situ reconstruction with the femoral veins. After discharge, the patients were followed at 6 monthly intervals with clinical examination, duplex and/or CT scan.

RESULTS

there were four in-hospital deaths (8%). One patient required above-knee amputation (2%) and there were two graft limb occlusions (4%). With a mean follow-up 41 months, another 13 patients died, unrelated to the operation (29%). There were no late amputations and only two late graft limb stenoses (4%). We have a 5 year survival rate of 60%, a 5 year limb salvage rate of 98%, and a 5 year primary patency rate of 91%. There were no cases of aneurysmal dilatation of vein grafts and no incidence of reinfection.

CONCLUSION

in situ reconstruction with the lower extremity deep veins is in the long term a safe and attractive alternative in the treatment of infrarenal aortic graft infection.

Cryopreservation prevents arterial allograft dilation

Historically, immune-mediated degradation and subsequent aneurysm formation have limited the usefulness of cryopreserved arterial allografts. This study tested the hypothesis that modern cryopreserved arterial allografts are protected from immune-mediated dilation. Abdominal aortas were harvested from anesthetized rats (Lewis and Brown-Norway) for immediate implantation or cryopreservation. Subsequently, Lewis rats underwent infrarenal aortic replacement with either an acutely harvested or a cryopreserved graft. There were four experimental groups: (1) acutely harvested isografts (Iso; n = 6), (2) cryopreserved isografts (C-Iso; n = 6), (3) cryopreserved allografts (C-Allo; n = 6), and (4) acutely harvested allografts (Allo; n = 6). All grafts were explanted at 8 weeks. A video camera and edge detection software were used to measure systolic and diastolic in vivo graft diameter (d). Measurement of arterial blood pressure (p) allowed calculation of compliance (Dd/Dp). Tail-cuff plethysmography was used to assess graft patency at 1 week. Graft diameter and blood pressure measurements were repeated at harvest. All harvested grafts were examined histologically. Our results showed that cryopreservation prevented immune-mediated dilation in arterial allografts in our 8-week rat implant model. Furthermore, the compliance of the cryopreserved grafts and was similar to that of controls. Further investigation is needed to delineate the exact mechanism of these potential clinically significant findings.

Complicated chronic pancreatitis causing mycotic aortic aneurysm: in situ replacement with a cryopreserved aortic allograft

Mycotic aortic aneurysm, which resulted from infected pancreatic pseudocysts with retroperitoneal abscess, developed in a patient with chronic pancreatitis. The aorta was approached through median laparotomy. Necrotic material was debrided from the pancreatic pseudocysts, and the mycotic aneurysm was resected. The aorta was replaced in situ with a cryopreserved aortic allograft. This report discusses the rare complication of pancreatic pseudocysts, which affect the infrarenal abdominal aorta and cause a large mycotic aneurysm. This case suggests that the use of cryopreserved allografts is promising for in situ reconstruction, even in a grossly infected field.

Surgical repair of infected peripheral graft and abdominal aortic aneurysm using arterial homograft

We report a case of combined surgical repair including lower limb revascularization (below-knee bypass) and abdominal aortic aneurysm repair using cryopreserved arterial homograft. The patient experienced lower limb ischemia due to repeated thrombosis of a long-infected polytetrafluoroethylene (PTFE) graft, and was also shown to have a complicating abdominal aortic aneurysm. Infection was eradicated with total graft excision and intravenous antibiotics. Two-year patency of the in situ arterial homograft revascularization was demonstrated with hemodynamic and tomographic controls; no degenerations have been found to date. Benefits of the use of in situ arterial homograft for arterial reconstruction may include improved hemodynamics and greater resistance to infection compared to when alloplastic materials are used. Because of the risk of allograft deterioration, close follow-up of the patient is required.