Tubular Reconstruction with Bovine Pericardium Xenografts to Treat Native Aortic Infections

Early and Mid-Term Results of Native and Abdominal Aortic Graft Infection Treatment via Surgeon-Constructed Porcine Pericardial Aortic Tubes

The search for optimal material for aortic infection reconstruction is ongoing. Our study presents the early and mid-term results of surgeon-constructed porcine pericardial tubes in the in-situ reconstruction of abdominal aortic infections, focusing on the safety as well as the durability of surgeon-created tubes. We performed a retrospective analysis of 8 patients treated for native aortic (n = 3) and aortic graft infections (n = 5) with surgeon-created tubes made of porcine pericardium patch (8 × 14 cm NO-REACT Ⓡ, BioIntegral Surgical Inc., Mississauga, ON, Canada). There were 7 males and 1 female, aged 68.5 (±4.8 years). Three patients had an aorto-enteric fistula. Technical success was obtained in all patients. Thirty-day mortality was 12.5% (n = 1). Mid-term follow-up was 12 months (2-63 months). One-year mortality was 37.5% (n = 3). Reintervention rate was 28.5% (n = 2). False aneurysm rate in the follow-up was 14.2% (n = 1). Surgeon-constructed porcine pericardial tubes seem to be a promising alternative as a replacement for native as well as graft-related abdominal aortic infections. The mid-term durability is encouraging, once the infection is controlled in cases with successful fistula repair and in native aortic infections patients. Further observations on larger groups, in longer follow-ups are necessary to confirm these preliminary observations.

Physician Made Bovine Pericardial Tube Grafts in Aortic Infection: A European Multicentre Study

OBJECTIVE

This study examines outcome and durability of physician made bovine pericardial tube grafts in aortic infections in all anatomical locations.

METHODS

This was a retrospective and prospective international multicentre study. Peri-operative and long term outcomes of patients undergoing in situ aortic reconstruction for native or graft infections with physician made bovine pericardial tube grafts between January 2008 and December 2020 in four European tertiary referral centres were analysed. The primary endpoint was recurrent aortic infection. Secondary endpoints were persistent infection, aortic re-operation for infection, graft related complications, and death.

RESULTS

One hundred and sixty eight patients (77% male, mean age 67 ± 11 years) were identified: 38 (23%) with native and 130 (77%) with aortic graft infection. The thirty day mortality rate was 15% (n = 26) overall, 11% (n = 4), and 17% (n = 22) for native and aortic graft infections, respectively (p = .45). Median follow up was 26 months (interquartile range [IQR] 10, 51). Estimated survival at one, two, three, and five years was 64%, 60%, 57%, and 50%, and significantly better for native (81%, 77%, 77%, and 69%) than for graft infections (58%, 55%, 51%, and 44%; p = .011). Nine patients (5.3%) had persistent infection and 10 patients (6%) had aortic re-infection after a median of 10 months (IQR 5, 22), resulting in an estimated freedom from re-infection at one, two, three, and five years of 94%, 92%, 90%, and 86%. Estimated freedom from graft complications at one, two, three, and five years was 91%, 89%, 87%, and 87%.

CONCLUSION

This multicentre study demonstrates low re-infection rates when using physician made bovine pericardial tube grafts, comparable to those of other biological grafts. The rate of graft complications, mainly anastomotic aneurysms and stenoses, was low, while graft degeneration was absent. Physician made bovine pericardial tube grafts are an excellent tool for in situ reconstruction in the setting of native aortic infection or aortic graft infection.

Outcomes Following Use of Bovine Pericardium (Xenoprosthetic) Grafts for Reconstruction of Mycotic Aortic Aneurysms and Infected Aortic Grafts: A Systematic Review and Meta-Analysis

BACKGROUND

Infected aortic grafts and mycotic aneurysms represent one of the most complex challenges faced by vascular surgeons. Treatment has progressed from extra-anatomical bypass to in situ reconstruction. Additionally, bovine pericardium reconstruction (BPR) has increased, due to accessibility and reduced lower limb morbidity. There remains, however, limited evidence for its use. The aim is to pool all known data to understand outcomes following BPR of mycotic aneurysms or infected vascular grafts.

METHODS

A systematic review was conducted in November 2021 with subsequent computerized meta-analysis of the pooled results and a final search in March 2022. Three databases, Excerpta Medica dataBASE (EMBASE), Cumulative Index of Nursing and Allied Health Literature (CINAHL), and National Institutes of Health PubMed (PubMed), were searched for the search term "(bovine OR xenoprosthetic) AND (aneurysm)", according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

From 9 studies, there were 133 patients: 67% graft infections and 33% mycotic aneurysms. Fifty-seven percent of reconstructions were in the abdominal aorta and 33% were in the thoracic aorta. One hundred fifty-eight pathogens were identified, including Staphylococcus aureus (23%), Candida albicans (13%), and Escherichia coli (13%). In 12%, no microorganisms were identified. Thirty-day mortality was 19.14% (CI 10.83-28.71), late mortality was 19.08% (confidence interval [CI] 7.76-32.83), and overall mortality was 40.20% (CI 29.82-50.97). One patient died intraoperatively. There were a total of 151 in-hospital complications after 30 days postoperation. Common complications were acute renal failure (17%), pneumonia (14%), delirium (12%), respiratory insufficiency (11%) and renal insufficiency (7%). Lower limb ischemia was low, occurring in 5.66% (CI 0.54-13.82) of patients. Loss of graft patency leading to reintervention occurred in 1.20% (CI 0.00-7.71) of the grafts. Reinfection rate was 0.00% (CI 0.00-1.21).

CONCLUSIONS

This meta-analysis highlights low reinfection and high graft patency using BPR with medium-length follow-up; however, there remain limited long-term and comparative data regarding options for aortic reconstruction. As expected in this complex cohort, the complication rate and 30-day mortality remain high.

Similar long-term outcomes for venous, bovine pericardial, and polyester patches for primary carotid endarterectomy

BACKGROUND

Currently, the type of patch used for carotid endarterectomy closure depends on the preference of the operating surgeon. Various materials are available, including autologous venous patches, bovine pericardial patches (BPP), and synthetic patches. The purpose of this study was to compare the long-term outcomes.

METHODS

All patients who underwent primary carotid endarterectomy with patch angioplasty using a venous, bovine, or polyester patch between 2010 and 2020 at two high-volume medical centers were included in this retrospective analysis on largely prospectively collected data. Study endpoints included long-term ipsilateral transient ischemic attack or cerebrovascular accident, restenosis, reintervention, and all-cause mortality. Cox proportional hazard models were fitted to assess the effect of patch type to each outcome.

RESULTS

In total, 1481 CEAs were performed with a follow-up of 32 (13-65) months. Venous patch was used in 309 patients (20.9%), BPP in 1000 patients (67.5%), and polyester patch in 172 patients (11.6%). A preoperative symptomatic carotid artery stenosis of >50% was observed in 91.9% (n = 284) of the patients who received a venous patch, 92.1% (n = 921) of the patients who received BPP, and 90.7% (n = 156) of the patients who received a polyester patch (p = 0.799). Only in selected patients with an asymptomatic stenosis of >70% surgery was considered. Multivariable analyses showed no significant differences between the three patch types regarding long-term outcomes after adjusting for confounders.

CONCLUSIONS

In patients undergoing primary carotid endarterectomy, the use of venous, bovine pericardial, or polyester patches seems equally safe and durable in terms of comparability in long-term outcomes.

Self-made bovine pericardial tube grafts for the treatment of abdominal aortic infections

OBJECTIVES

Aortic infections are an uncommon but life-threatening disease. The material of choice for aortic reconstruction is still a matter of debate. The aim of this study is to examine the short and mid-term outcomes in the treatment of abdominal aortic infections using self-made bovine pericardium tube grafts.

MATERIAL AND METHODS

This retrospective, single-center study collected all patients who underwent in situ abdominal aortic reconstruction using self-made bovine pericardial tube grafts between February 2020 and December 2021 in a tertiary care center. Patient comorbidities, symptoms, radiological, bacteriological and peri-operative findings, as well as postoperative outcomes were analyzed.

RESULTS

Bovine pericardial aortic tube grafts were used in 11 patients (10 male, median age 68.7 years). Two patients presented a native aortic infection and nine had graft infections (four bypass grafts, four endografts and a plurioperated patient who had undergone both endovascular and open procedures). There were two emergent surgeries due to infectious aneurysm ruptures. All patients were symptomatic and the most frequent clinical finding was lumbar or abdominal pain (36%), followed by wound infection (27%) and fever (18%). Seven bifurcated and four straight pericardial tube grafts were needed. Purulent drainage was obtained around the previous graft or in the aneurysmal sac in 7 cases; intraoperative cultures were positive in 6 cases (Gram + bacteria). Two patients died in the immediate postoperative period (perioperative mortality 18%; urgent procedures 50%; scheduled procedures 11%). One patient had a major complication due to bilateral SARS-CoV2 pneumonia. There was one single reintervention to control hemostasis due to bleeding non-graft-related. The median follow-up was 14.1 months (3-24 months).

CONCLUSIONS

Our preliminary experience in the treatment of abdominal aortic infections by in situ reconstrucción with self-made bovine pericardial tube grafts shows promising results. These should be confirmed in the long term.

Methicillin-Susceptible Staphylococcus aureus Biofilm Formation on Vascular Grafts: an In Vitro Study

The aim of this study was to quantify in vitro biofilm formation by methicillin-susceptible Staphylococcus aureus (MSSA) on the surfaces of different types of commonly used vascular grafts. We performed an in vitro study with two clinical strains of MSSA (MSSA2 and MSSA6) and nine vascular grafts: Dacron (Hemagard), Dacron-heparin (Intergard heparin), Dacron-silver (Intergard Silver), Dacron-silver-triclosan (Intergard Synergy), Dacron-gelatin (Gelsoft Plus), Dacron plus polytetrafluoroethylene (Fusion), polytetrafluoroethylene (Propaten; Gore), Omniflow II, and bovine pericardium (XenoSure). Biofilm formation was induced in two phases: an initial 90-minute adherence phase and a 24-hour growth phase. Quantitative cultures were performed, and the results were expressed as log10 CFU per milliliter. The Dacron-silver-triclosan graft and Omniflow II were associated with the least biofilm formation by both MSSA2 and MSSA6. MSSA2 did not form a biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the Omniflow II graft was 3.89 CFU/mL (standard deviation [SD] 2.10). The mean count for the other grafts was 7.01 CFU/mL (SD 0.82). MSSA6 formed a biofilm on both grafts, with 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean biofilm growth on the remaining grafts was 7.33 CFU/mL (SD 0.28). The differences in biofilm formation on the Dacron-silver-triclosan and Omniflow II grafts compared to the other tested grafts were statistically significant. Our findings suggest that of the vascular grafts we studied, the Dacron-silver-triclosan and Omniflow II grafts might prevent biofilm formation by MSSA. Although further studies are needed, these grafts seem to be good candidates for clinical use in vascular surgeries at high risk of infections due to this microorganism. IMPORTANCE The Dacron silver-triclosan and Omniflow II vascular grafts showed the greatest resistance to in vitro methicillin-susceptible Staphylococcus aureus biofilm formation compared to other vascular grafts. These findings could allow us to choose the most resistant to infection prosthetic graft.

Xenogeneic materials for the surgical treatment of aortic infections

Background

The surgical treatment of aortic infections (AIs) is challenging. In situ aortic reconstructions represent nowadays the favored therapy for fit patients and xenogeneic materials are used increasingly. The aim of this study was to present our experience with xenogeneic reconstructions for AI using self-made bovine pericardium tubes and/or the biosynthetic Omniflow^® II graft.

Methods

This retrospective single-center study included all patients undergoing xenogeneic aortic and aortoiliac reconstructions from December 2015 to June 2020. Patient comorbidities, symptoms, procedural characteristics, types of pathogens and postoperative outcomes were analyzed.

Results

Twenty-eight patients [23 male (82%), median age 68 (range, 28–84) years] were included. Ten patients (36%) had native AIs and 18 (64%) had graft infections, including 3 (11%) aortoesophageal and 2 (7%) aortoduodenal fistulas (ADF). Twenty-four patients (86%) were symptomatic, the most common symptoms being contained aortic rupture (n=8) and sepsis (n=4). The surgical procedures were infra- and juxtarenal aortic repairs (n=11, 39% and n=7, 25%), thoracoabdominal aortic repairs (type IV: n=1, 4%; type V: n=3, 11%), descending thoracic aortic repairs (n=4, 14%) and 2 reconstructions (7%) involving the ascending aorta/aortic arch. Most were urgent (n=10, 43%) or emergent operations (n=11, 35%). Identification of pathogen(s), mostly Gram-positive bacteria, was possible in 25 patients (89%). Twelve patients (43%) had polymicrobial infections and 6 (21%) infections with multi-resistant bacteria. In-hospital mortality was 32% (n=9) due to acute cardiac failure (1/9), endocarditis (1/9), bleeding (3/9) and sepsis (4/9). The most frequent complications were transient need for dialysis (n=12, 43%) and persisting sepsis (n=11, 39%). Two early occlusions of Omniflow^® II grafts were observed (7%). Median follow-up (FU), during which 2 patients died of non-aortic causes, was 14 months (95% CI: 9–19 months). Freedom from reoperation was 100%, there was no evidence for reinfection during FU.

Conclusions

Xenogeneic orthotopic reconstructions for AI can be performed at all aortic levels. Combining bovine pericardium and the Omniflow^® II graft can be useful for reconstructing the branched aortic segments and both materials show appropriate early to midterm outcomes. Nonetheless, AIs are serious conditions associated with relevant morbidity/mortality rates, even in a specialized center.