Ten Years Experience of Treating Aorto-Femoral Bypass Graft Infection with Venous Allografts

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.

Neoaortoiliac system and cryopreserved human allograft for the treatment of aortic graft infections

OBJECTIVE

To report and compare neoaortoiliac system reconstruction and cryopreserved human allograft in treating aortic graft infections.

METHODS

We retrospectively analysed the data of the patients treated for aorto graft infections between January 2015 and May 2021 in our hospital. The clinical data, diagnostic procedures, and surgical options were evaluated. The primary endpoint of this study was the 30-day and 1-year mortality; secondary endpoints were major postoperative complications.

RESULTS

We retrospectively reviewed a series of 31 consecutive patients (28 males; median age 72 years, range, 50-87 years) with aortic graft infection treated with NAIS (n = 20, 65%) or cryopreserved allograft (n = 11, 36%). The clinical presentation included fever attacks in 18 (58%) patients, abdominal pain in 15 (48%) patients, haemodynamic instability in 6 (19%) patients, and haematemesis in 2 (7%) patients. The median operative time of the NAIS was longer than CHA without a statistically significant difference (458 min vs. 359 min, p = .505). The postoperative morbidity for all patients was 81%, with no significant difference between NAIS and CHA groups (85% vs. 73%, p = .638). There was no limb thrombosis of the new reconstructions. Limb loss occurred in 4 (13%) patients, including 2 (10%) NAIS patients and 2 (18%) CHA patients. One NAIS patient developed complications in the form of a distal (femoral) disruption of the vein 15 days after surgery. There were no significant differences between NAIS and CHA groups in ICU stay (12 vs 8 days, .984) but in hospitalization (22 vs 33, p = .033). The most common bacteria isolated were staphylococci strains in 15 (48%). In 13 (36%) patients, candida was positive. The in-hospital 30-day and 1-year mortality for all patients was 16% (5/31) and 29% (9/31), with no significant differences between NAIS and CHA at 30 days (25% vs. 0, p = .133) or 1 year (35% vs. 18%, .429). Five NAIS patients died during the hospital stay; three of them had end-of-life decisions. After a median follow-up of 16 months (1-66 months), 12 (39%) patients died, including 9 patients with NAIS and 3 with CHA reconstructions. The causes of death included overwhelming sepsis in 5 (42%) patients, graft disruption in one (8%) NAIS patient, non-small cell lung cancer in one (8%) patient, COVID-19 in one (8%) patient and unknown causes (8%) in one.

CONCLUSIONS

Non-staged neoaortoiliac system reconstruction and cryopreserved human allografts show comparable short- and midterm results for treating aortic graft infections. However, both procedures remain challenging with high morbidity and mortality rates.

Neoaortoiliac system in treating aortic graft infections: a single center long-term experience and review of the literature

BACKGROUND

Aortic graft infection represents one of the most challenging and life-threatening complication of surgical and endovascular treatment of aortic pathologies. The aim of this study was to report the results of a single center with in-situ revascularization for the treatment of aortic graft infections using the neo-aorto-iliac system (NAIS) and to review the literature about this surgical technique.

METHODS

We retrospectively reviewed our aortic graft infection case series and in-situ revascularization using the neo-aorto-iliac system. The study was conducted from January 2009 to June 2020. The primary outcomes analyzed were early mortality (<30 days), late mortality (>30 days), reinfection rate. Secondary outcomes were the primary patency rate, the secondary patency rate, and the lower limb salvage rate. A literature review of the last twenty years was performed on international medical databases Pubmed (Medline), Scopus and Web of Science.

RESULTS

During study period, 12 patients, all male (median age of 69 years [range: 52-87 years]), underwent to infected graft explantation and revascularization by NAIS using femoral-popliteal veins. Six cases were complicated by aorto-enteric fistulas, five were duodenal and one was colon. Patients spent the immediate postoperative period in the Intensive Care Unit for a median time of 4 days (range: 0-9 days). The median length of hospital stay was 27.5 days (range: 1-66 days). The mean follow-up was 21.5 months (range: 0-120). The 30-day mortality rate was 25% (3 patients) due to postoperative complications. No patient dropped out of the follow-up protocol. The primary patency rate was 92% while the secondary patency rate was 100%. No patient underwent lower limb amputation. Persistence of infection occurred in 1 case (8.3%). Overall Kaplan-Meier survival estimates were 75% for 30 days, 50% for 1 year, 48% for 5 years. Literature analysis identified 19 case series.

CONCLUSIONS

The literature regarding NAIS has low statistical evidence due to retrospective design of the studies. Our results are in agreement with retrospective studies in the literature. When the surgical team is confident with NAIS, this technique should be considered the preferred method, considering an acceptable and comparable mortality rate with other techniques and a better rate of patency, resistance to graft degeneration, recurrent infections and amputation rate.

Cryopreserved Venous Allografts in Supra-inguinal Reconstructions: A Single Centre Experience

OBJECTIVE

This study introduces a novel technique for supra-inguinal arterial reconstructions with cryopreserved femoral vein and caval allografts with a low re-infection rate and an acceptable graft re-intervention rate on early mid term analysis.

METHODS

Patients treated from February 2012 to March 2018 with cryopreserved venous allograft reconstructions owing to infection in the supra-inguinal area were reviewed retrospectively. The primary end points were re-infection and the treatment related mortality rate. Secondary end points were 30 and 90 day and overall mortality and graft re-intervention rate.

RESULTS

Of the 23 patients treated with cryopreserved venous allografts for infection in aorto-iliac area, 21 (91%) patients underwent reconstruction with cryopreserved femoral veins and two (9%) with vena cava. Indications for treatment were aortic graft infections (n = 12 [52%]), mycotic aneurysms (n = 5 [22%]), femorofemoral prosthetic infections (n = 3 [13%]), anastomotic pseudo-aneurysms (n = 2 [9%]), and aortic thrombosis with intestinal spillage (n = 1 [4%]). In hospital and 90 day mortality were 9% (n = 2); overall treatment related mortality during the median follow up of 15 months was 13% (n = 3). During the follow up, two allografts were re-operated on owing to anastomotic dilatation and one because of re-infection, resulting in a re-intervention rate of 13% (n = 3). None of the grafts was lost and there were no amputations. At the end of follow up 17 patients (74%) were alive. Kaplan-Meier estimation for survival was 76% (95% confidence interval [CI] 57%-95%) at one year and 70% (95% CI 49%-91%) at two years.

CONCLUSION

Cryopreserved venous allografts appear to be an infection resistant and reasonably safe reconstruction material in the aorto-iliac axis based upon the early mid term analysis from a single centre experience. Further research is needed to compare their performance with other biological reconstruction material.

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.

Aortobisiliac Bypass Using a Venous Homograft Concomitant With Kidney Transplantation in a Patient With Severe Bilateral Iliac Occlusive Disease: A Case Report

Aortoiliac occlusive disease (AOD) is a great threat for kidney transplantation (KT). Here we report the case of an aortoiliac bypass, performed simultaneously with renal transplantation using venous grafts obtained from the deceased donor. The recipient was a 68-year-old woman with significant stenosis of the aortoiliac axis. We performed an aortobisiliac bypass using donor's femoral veins because presence of methicillin-resistant Staphylococcus aureus was detected on donor hemoculture and contraindicated a prosthetic implant on the recipient. KT was then carried out using standard technique. Operative time amounted to 330 minutes and cold ischemia time of the renal graft was 900 minutes. Delayed graft function was observed until postoperative day 12, but the patient showed a good urine output and a serum creatinine of 2.1 mg/dL at discharge. AOD is not an absolute contraindication to renal transplantation, and simultaneous surgical repair of aortoiliac lesions with KT seems feasible. The patient's return to function after initial delayed graft function suggests that such interventions may allow transplantation to be offered to those patients who otherwise may be excluded for severe vascular comorbidities. Homologous vascular grafts are an excellent choice because prosthetic vascular replacement during immunosuppression must be avoided as long as possible, especially in patients with coexisting infective risk.

Cold-Stored Venous Allografts In Different Preserving Solutions: A Study On Changes In Vein Wall Morphology

BACKGROUND:

The saphenous vein is the most frequently used bypass conduit for vascular reconstructions, which may need to be stored for a prolonged time. The aim of this study was to compare the effect of different preservation solutions on the morphology of saphenous veins during the long-term cold storage.

DESIGN:

An in vitro study.

MATERIAL AND METHODS:

Saphenous vein samples, collected from 29 patients undergoing varicose vein surgery, were stored at +4°C in (1) 10% formalin, (2) isotonic saline with heparin and antibiotic, (3) phosphate-buffered saline, (4) 2.5% glutaraldehyde + phosphate-buffered saline, and (5) Custodiol (histidine-tryptophan-ketoglutarate). Changes in the vein wall were histologically investigated up to day 35. Possible retention of the capacity of endothelial function was evaluated by immunohistochemical detection of endothelial nitric oxide synthase.

RESULTS:

Formalin as the control medium well preserved the vein wall morphology, but endothelial nitric oxide synthase immunostaining was very weak. Phosphate-buffered saline and isotonic saline with heparin and antibiotic poorly preserved vein wall morphology. Phosphate-buffered saline endothelial nitric oxide synthase staining decreased dramatically throughout the study period. Compared to phosphate-buffered saline, stronger isotonic saline with heparin and antibiotic endothelial nitric oxide synthase staining was noted at day 35 (p < 0.001). Custodiol and glutaraldehyde better preserved vein morphology compared to ISHA and PBS at day 5 and later (p < 0.001), but compared to stronger isotonic saline with heparin and antibiotic their endothelial nitric oxide synthase staining was weaker.

CONCLUSION:

In terms of preserving the morphology of saphenous veins, phosphate-buffered saline and isotonic saline with heparin and antibiotic were the poorest, while Custodiol and glutaraldehyde were the best. Demonstrating good retention of endothelial nitric oxide synthase staining throughout the study period, isotonic saline with heparin and antibiotic seems to have the best potential to retain vein wall functionality, despite relatively poor morphological preservation.

Surgical Treatment of Native and Prosthetic Aortic Infection With Xenopericardial Tube Grafts

BACKGROUND

The study sought to report our results of surgical treatment of native and prosthetic aortic infection with xenopericardial tube grafts from the ascending aorta to beyond the bifurcation.

METHODS

Within a 28-month period, 20 patients were treated with a bovine self-made pericardial tube graft to replace infected vascular grafts (after conventional surgical aortic replacement or endovascular stent graft implantation) or to treat a contaminated surgical site. An integrated standardized therapeutic concept was applied in all patients, consisting of complete removal of the infected prosthetic material, extensive debridement, and orthotopic vascular reconstruction with self-made tube grafts constructed from a bovine pericardial patch.

RESULTS

Four patients died perioperatively (20%) due to sepsis, pulmonary failure, or sudden circulatory arrest. The mean follow-up was 18 months (first quartile 2, third quartile 17 months). Interval computed tomography scans revealed 100% freedom from proven aortic reinfection, but reinfection cannot be ruled out in 4 patients who died of unknown causes during follow-up or because of ongoing sepsis. Three patients required aortic reintervention for a suture-line aneurysm, for graft occlusion, and for the development of a neoaortointestinal fistulation, respectively.

CONCLUSIONS

Patients with infectious aortic disease present in a frail state and the initial and the late mortality is substantial. Yet, surgical treatment of native and prosthetic aortic infection with xenopericardial tube grafts shows promising short-term results with regard to durability and freedom from reinfection in any aortic segment. Further studies are needed to learn of the long-term behavior of these grafts.

A Meta-Analysis of Outcomes After In Situ Reconstructions for Aortic Graft Infection

OBJECTIVE

To confirm the advantage of in situ reconstruction (ISR) over extra-anatomic reconstruction (EAR) for aortic graft infection and determine the most appropriate conduit including autogenous veins, cryopreserved allografts, and synthetic prosthesis (standard, rifampicin of silver polyesters).

METHODS

A meta-analysis was conducted with rate of mortality, graft occlusion, amputation, and reinfection. A meta-regression was performed with 4 factors: patients' age, presence of prosthetic-duodenal fistula (PDF), virulent organisms, or nonvirulent organisms.

RESULTS

In situ reconstruction over EAR seems to favor all events. For the 5 conduits used for ISR, according to operative mortality, age of the patients looks to have a positive correlation only for silver polyester and no conduit present any advantage in the presence of PDF. Reinfection seems to be not significantly different for the 5 conduits, and only autogenous veins appear to have a positive correlation with infecting organisms.

CONCLUSION

In situ reconstruction may be considered as first-line treatment. Our results suggest that silver polyesters appear to be most appropriate for older patients, and in order to limit reinfection, autogenous veins are probably the most suitable conduit.

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.

Bovine Pericardium as New Technical Option for In Situ Reconstruction of Aortic Graft Infection

BACKGROUND

Alloplastic aortic graft infection is a devastating complication following aortic surgery. It is associated with excessively high mortality and morbidity caused by anastomotic rupture or septicemia. Many authors consider in situ replacement after complete surgical graft removal as the method of choice. However, there is an ongoing debate about the most suitable material for reconstruction. We present our first experiences with replacing the descending and infrarenal aorta using custom-made bovine pericardium grafts.

MATERIAL AND METHODS

From January 2013 to 2015, 13 patients (10 male, median age 70 years, range 53-84) were treated for 5 early-graft infections after open reconstructions and 7 late graft infections (1 TEVAR, 2 EVAR, and 4 open reconstructions), and 1 patient was treated for mycotic aneurysm. Septicemia was evident in 8 patients, whereas 5 patients were presented with low-grade infection. In all cases, graft infection was proven by a synopsis of clinical findings, laboratory tests, imaging, and microbiologic tests (positive pathogen detection in 11 patients). Cutaneous and aortoenteric fistulae were present in 3 and 4 patients, respectively. All patients received an in situ replacement using a hand-sewn xenoprosthesis or patch made from a bovine pericardium sheet. Follow-up was routinely performed 3, 12, and 24 months after discharge.

RESULTS

For reconstruction, 4 pericardium tubes, 7 bifurcated grafts, and 2 large patches were implanted in situ. Technical success was 100%. Median length of hospital stay was 44 days (range, 20-136 days), with an in-hospital mortality rate of 7.7% (n = 1). Major procedure- and disease-related complications were temporary (n = 2) and permanent dialysis (n = 1), limb loss (n = 1), and long-term ventilation (n = 5). Complete infection control and initial healing could be achieved in 75% (n = 10). During the follow-up (median 9 months, range: 1-27 months), primary graft patency was 100%, and mortality was 41.7%. We observed 2 secondary ruptures due to reinfection at 4 and 7 months.

CONCLUSIONS

Custom-made bovine pericardium grafts provide a good option for in situ replacement following early or late aortic graft infection. Despite of its high biocompatibility, pericardium provides not an absolute protection against ongoing retroperitoneal infection. For the treatment, the principles of septic surgery need to be applied and close follow-up is mandatory.

Salvage of infected vascular graft via 'perivascular venous banding' technique coupled with rectus abdominis myocutaneous muscle flap transposition

This is the case of a severe Pseudomonas aeruginosa biological vascular graft infection, completely involving the perianastomotic tract of a femoro - femoral crossover bypass and resulting in repeated bleeding from the offended vessel wall. After the failure of a sartorious rotational muscle flap transposition into the infected groin wound, this 'high-grade' vascular graft infection was finally treated successfully by wrapping a great saphenous vein patch reinforcement circumferentially around the damaged biological vascular conduit and filling the infected wound with a rectus abdominis myocutaneous muscle flap transposition. The aim of this report is to illustrate this novel, to our knowledge, 'perivascular venous banding' technique and to evaluate the prospective of future testing of this surgical procedure. Starting from this singular case, we will also review the role of the rotational muscle flaps in the conservative management of major vascular graft infections.