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.

Ten-year experience with use of cryopreserved allografts for redo infrapopliteal bypass

INTRODUCTION

The aim of this study is to report the early and late outcomes of cryopreserved saphenous vein (CSV) in redo infrainguinal bypass and to investigate possible predictors of primary patency loss.

METHODS

All patients who underwent a redo bypass for critical limb ischemia from January 2010 to December 2020 were reviewed. Early and late complications were analyzed and included. The endpoints of the study were all cause mortality, major limb amputation, and primary patency (PP).

RESULTS

Data were collected from 95 patients. Among the entire cohort, 16 (16.8%) patients received a cryopreserved vessel bypass with anastomosis in the popliteal artery and 79 (83.2%) patients had cryopreserved vessel bypasses with distal anastomosis in tibial vessels. Median duration of follow-up was 73 months; during this, period estimated survival at 5 years was 80.5 ± 4% (95% CI, 78.0-91.2) and estimates of freedom from limb amputation was 90.3 ± 3.2% (95% CI, 87.3-98.1). Overall, the estimated primary patency of the bypass was 43.7 ± 6.7% (95% CI, 30.2-51.4). On multivariable analysis, intraprocedural tibial vessel angioplasty (HR = 2.3, p = 0.01), distal anastomosis in tibial vessels (HR = 3.6, p = 0.36), and the use of a composite graft (HR = 2.4, p = 0.01) were independently associated with loss of PP.

CONCLUSIONS

The use of CSV in redo bypass is an effective strategy in salvaging threatened lower extremities and in preventing or delaying limb amputation. Our results confirm that further attempts at revascularization are generally appropriate, even in technically changing patients.

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.

Resistance to infection of long-term cryopreserved human aortic valve allografts

OBJECTIVE

To analyze the in vitro antimicrobial activity of 3 antibiotic regimens (group A, gentamicin-piperacillin-vancomycin-metronidazole-amphotericin B; group B, gentamicin-piperacillin-flucloxacillin-metronidazole-amphotericin B; and group C, meropenem-vancomycin-tobramycin-colistin-amphotericin B) used in the processing of cryopreserved human ascending aortic tissue and aortic valves against Staphylococcus epidermidis and Staphylococcus aureus. The results were additionally compared with the infection resistance of cryopreserved ascending aortic tissue against Escherichia coli and Pseudomonas aeruginosa.

MATERIALS

Each of 10 cryopreserved human allografts (CHAs) was divided into 25 pieces (separating aortic wall and valve). Eighteen segments were microbiologically tested, and 7 pieces underwent scanning electron microscopy. A bacterial solution (4 mL; optical density, 0.20 ± 0.02) was used for contamination. After incubation, the optical density of the solution was measured. CHAs underwent sonication to release viable adherent bacteria. The number of attached bacteria was quantified by the colony forming units per square centimeter of CHA surface.

RESULTS

Antibiotic regimen groups B and C were more efficient than group A in eradicating gram-positive organisms adherent to the aortic wall (P < .001). Group C showed enhanced resistance against E coli compared with group A or B (P < .001), whereas group B appeared to be more effective against P aeruginosa (P < .001). With reference to each antibiotic regimen, ascending aortic tissue showed significantly less bacterial contamination with staphylococcal bacteria than valve grafts (P ≤ .01).

CONCLUSIONS

CHAs possess antibacterial activity despite long-term storage over 5 years. Antibiotic combinations applied during CHA processing have a significant influence on their infection resistance. Ascending aortic tissue shows a significantly enhanced bacterial resistance against staphylococcal bacteria compared with aortic valves.