A systematic review and meta-analysis of the use of the Omniflow II biosynthetic graft for aortic reconstruction

OBJECTIVE

Despite the improvements in xenogeneic grafts and surgical techniques, management of aortic graft infection has remained challenging. The optimal graft material has remained controversial, with high rates of reinfection using prosthetic grafts and a limited time for venous harvest in an emergent setting. Recent studies have highlighted an increase in the use of Omniflow II biosynthetic vascular grafts (LeMaitre Vascular, Burlington, MA) for aortic reconstruction. The primary aim of the present study was to review the key outcomes for the Omniflow II graft in terms of reinfection and complications.

METHODS

The National Healthcare Service healthcare databases advanced search function was used to search nine databases for the search term "Omniflow." The present study complied with the PRISMA (preferred reporting items for systematic review and meta-analysis) statement. Eligible studies related to aortic graft infection or in situ aortic reconstruction were selected in accordance with prespecified eligibility criteria and included for review. Data on the surgical technique, comorbidities, graft reinfection, mortality, and complications were combined. The data were analyzed using Stata/MP, version 17 (StataCorp, College Station, TX), and the probabilities were pooled using a DerSimonian and Laird random effects model with Freeman-Tukey arcsine transformation.

RESULTS

Six studies with 60 patients (44 men; age range, 29-89 years) were included. Of the 60 patients, 25 had undergone surgical reconstruction because of early graft infection (<4 months after the index procedure), 24 for late graft infection, and 3 because of mycotic aneurysms. Eight high-risk patients had undergone surgical reconstruction for prevention of an initial graft infection. Staphylococcus aureus, Escherichia coli, and S. epidermis were the most common organisms. Early mortality was 8.83% (95% confidence interval [CI], 1.12%-20.53%), and late mortality was 18.49% (95% CI, 5.51%-35.34%). Follow-up varied from 9 months to 2 years. No graft rupture or graft degeneration had occurred during follow-up. However, 6.2% (95% CI, 0.39%-15.81%) had experienced early graft occlusion, and 3.83% (95% CI, 0.00%-16.34%) had developed early graft stenosis. Two cases of postoperative reinfection were reported. The freedom from reinfection was 97.71% (95% CI, 87.94%-100.00%).

CONCLUSIONS

Use of the Omniflow II graft for aortic reconstruction is a feasible alternative with acceptable mortality and low reinfection rates. However, there is a risk of limb occlusion. Although these studies were of low quality, the Omniflow II graft shows promise in this difficult patient cohort, especially when bifurcated reconstruction is required.

Contemporary results with the biosynthetic glutaraldehyde denatured ovine collagen graft (Omniflow II) in lower extremity arterial revascularization in a septic context

OBJECTIVE

Prosthetic peripheral vascular graft infections are poorly evaluated, despite a grim prognosis with high mortality and major amputation rates. The vascular substitute of choice remains controversial when autologous veins are unavailable. The main objective of this study was to evaluate the mid-term results of a new alternative biosynthetic collagen graft (Omniflow II®) in an infected field in patients with unavailable or unsuitable autologous saphenous vein.

METHODS

This retrospective, observational, multicentric study included all consecutive patients in whom an Omniflow II® graft was used for infra-inguinal revascularization in the context of sepsis from January 2015 to January 2020. The primary endpoint was freedom from major amputation; secondary endpoints were 30-day mortality, perioperative morbidity, and estimated survival, patency, and freedom from reinfection estimated using the Kaplan-Meier method.

RESULTS

Twenty-nine patients (27 men, median age 69 years (IQR:60;76) were included. Fever was present in 58.6% of cases, a septic rupture in 17.9%, and a pseudo-aneurysm in 25.0%. The 30-day mortality rate was 3.4% (septic shock). The median follow-up reached 49 months. At 1 and 3 years, the estimated freedom from major amputation was 88.4% and 83.9%, survival was 96%, primary patency was 74.6% and 65.8%, secondary patency was 82.1% and 77.7% and reinfection free-survival was 85.6%. There were 7 occlusions (1 iliofemoral, 1 below-knee, and 5 above-knee bypasses), 3 explantations for persistent sepsis, 4 reinfections (all within the first 6 months which led to 1 death and 3 major amputations), and a total of 4 major amputations. The risk of major amputation increased with bypass reinfection (p=.004), occlusion (p=.005), and polymicrobial infection (p=.05).

CONCLUSION

In a septic context, the Omniflow II® bioprosthetic graft represents an acceptable vascular substitute in the absence of an autologous vein. It provides acceptable freedom from major amputation and reinfection considering the seriousness of this pathology. This usage remains outside the instructions for use, it is, therefore, essential to pursue longer-term studies in larger cohorts.

The potential for Lactoferrin to reduce SARS-CoV-2 induced cytokine storm

The COVID-19 pandemic is a serious global health threat caused by severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2). Symptoms of COVID-19 are highly variable with common hyperactivity of immune responses known as a "cytokine storm". In fact, this massive release of inflammatory cytokines into in the pulmonary alveolar structure is a main cause of mortality during COVID-19 infection. Current management of COVID-19 is supportive and there is no common clinical protocol applied to suppress this pathological state. Lactoferrin (LF), an iron binding protein, is a first line defense protein that is present in neutrophils and excretory fluids of all mammals, and is well recognized for its role in maturation and regulation of immune system function. Also, due to its ability to sequester free iron, LF is known to protect against insult-induced oxidative stress and subsequent "cytokine storm" that results in dramatic necrosis within the affected tissue. Review of the literature strongly suggests utility of LF to silence the "cytokine storm", giving credence to both prophylactic and therapeutic approaches towards combating COVID-19 infection.

In the Age of Viral Pandemic, Can Ingredients Inspired by Human Milk and Infant Nutrition Be Repurposed to Support the Immune System?

In 2020, with the advent of a pandemic touching all aspects of global life, there is a renewed interest in nutrition solutions to support the immune system. Infants are vulnerable to infection and breastfeeding has been demonstrated to provide protection. As such, human milk is a great model for sources of functional nutrition ingredients, which may play direct roles in protection against viral diseases. This review aims to summarize the literature around human milk (lactoferrin, milk fat globule membrane, osteopontin, glycerol monolaurate and human milk oligosaccharides) and infant nutrition (polyunsaturated fatty acids, probiotics and postbiotics) inspired ingredients for support against viral infections and the immune system more broadly. We believe that the application of these ingredients can span across all life stages and thus apply to both pediatric and adult nutrition. We highlight the opportunities for further research in this field to help provide tangible nutrition solutions to support one's immune system and fight against infections.