Neurological improvement following revision of vascular graft remnants in the upper extremity.

Remnant vascular grafts may result in significant neurological deficits owing to compression of adjacent neural structures. We report this finding in two cases after extracorporeal membrane oxygenation decannulation and removal of an arteriovenous fistula in the upper extremity. In both cases, removal of the graft, patch arteriotomy, and external neurolysis resulted in significant recovery of neurological function. We review the preoperative workup, diagnostic studies, and technical approach to treatment in an effort to increase recognition among vascular and cardiovascular surgeons and to demonstrate a safe and effective management option through a multidisciplinary approach.

Identification of a subpopulation of highly adherent endothelial cells for seeding synthetic vascular grafts.

OBJECTIVE: There is an unmet clinical need for alternatives to autologous vessel grafts. Small-diameter (<6mm) synthetic vascular grafts are not suitable because of unacceptable patency rates. This mainly occurs due to the lack of an endothelial cell (EC) monolayer to prevent platelet activation, thrombosis, and intimal hyperplasia. There are no reliable methods to endothelialize small-diameter grafts, as most seeded ECs are lost due to exposure to fluid shear stress (SS) after implantation. The goal of this work is to determine if EC loss is a random process or if it is possible to predict which cells are more likely to remain adherent. METHODS: In initial studies, we sorted ECs using fluid SS and identified a subpopulation of ECs that are more likely to resist detachment. We use RNA-sequencing (RNA-seq) to examine gene expression of adherent ECs compared to the whole population. Using fluorescence activated cell sorting (FACS), we sorted ECs based on the expression level of a candidate marker and studied their retention in small-diameter vascular grafts in vitro. RESULTS: Transcriptomic analysis revealed that fibronectin leucine rich transmembrane protein 2 (FLRT2), encoding protein FLRT2, is downregulated in the ECs that are more likely to resist detachment. When seeded onto vascular grafts and exposed to SS, ECs expressing low levels of FLRT2 exhibit 59.2±7.4% retention compared to 24.5±6.1% retention for the remainder of the EC population. CONCLUSIONS: For the first time, we show EC detachment is not an entirely random process. This provides validation for the concept that we can seed small-diameter vascular grafts only with highly adherent ECs to maintain a stable endothelium and improve graft patency rates.

Nitric Oxide Releasing Nanomaterials for Cardiovascular Applications.

A central paradigm of cardiovascular homeostasis is that impaired nitric oxide (NO) bioavailability results in a wide array of cardiovascular dysfunction including incompetent endothelium-dependent vasodilatation, thrombosis, vascular inflammation, and proliferation of the intima. Over the course of more than a century, NO donating formulations such as organic nitrates and nitrites have remained a cornerstone of treatment for patients with cardiovascular diseases. These donors primarily produce NO in the circulation and are not targeted to specific (sub)cellular sites of action. However, safe, and therapeutic levels of NO require delivery of the right amount to a precise location at the right time. To achieve these aims, several recent strategies aimed at therapeutically generating or releasing NO in living systems have shown that polymeric and inorganic (silica, gold) nanoparticles and nanoscale metal-organic frameworks could either generate NO endogenously by the catalytic decomposition of endogenous NO substrates or can store and release therapeutically relevant amounts of NO gas. NO-releasing nanomaterials have been developed for vascular implants (such as stents and grafts) to target atherosclerosis, hypertension, myocardial ischemia-reperfusion injury, and cardiac tissue engineering. In this review, we discuss the advances in design and development of novel NO-releasing nanomaterials for cardiovascular therapeutics and critically examine the therapeutic potential of these nanoplatforms to modulate cellular metabolism, to regulate vascular tone, inhibit platelet aggregation, and limit proliferation of vascular smooth muscle with minimal toxic effects.

Carotid Artery Reconstruction with an Autologous Bifurcated Saphenous Vein Graft.

We present a new technique for carotid artery reconstruction using a modified bifurcated saphenous vein graft in a patient with a malignant neck tumor. This technique can optimize the size match between the SVG and common carotid artery, as well as the internal and external carotid arteries. Post operative computed tomography performed a year after the operation demonstrated excellent graft alignment and patent carotid arteries.

Harnessing the Coil Electrospinning Method for Fabricating Superflexible and Multiscale-Patterned Fibrous Tubular Scaffolds with Topographical Features.

The fibrous tubular scaffold (FTS) has potential as a vascular graft; however, its clinical application is hindered by insufficient mechanical properties. Inadequate mechanical properties of vascular grafts can lead to some serious side effects such as intimal hyperplasia, luminal expansion, and blood thrombogenicity. In this study, we developed a novel fibrous tubular scaffold comprising multiscale fibers to ensure superior mechanical properties. Our novel approach involves a one-step manufacturing method that can fabricate the superflexible fibrous tubular scaffold (SF-FTS) with topographical features via a modified electrospinning setup. We investigated the effect of humidity and temperature during the fabrication process on the formation of multiscale fibers. It was demonstrated that the incorporation of multiscale fibers and topographical features significantly enhances the mechanical properties of FTS. The mechanical advantages of SF-FTS were confirmed through the kinking resistance test, compressive test, and in vivo experiments. Additionally, we explored the interaction between the multiscale fibers and human umbilical vein endothelial cells (HUVECs) behavior. Our results suggest a novel strategy for fabricating FTS with advanced mechanical properties, and the designed SF-FTS holds promise as a potential candidate for clinical applications.

Comparative outcomes of arterial bypass using the human acellular vessel and great saphenous vein in patients with chronic limb ischemia.

OBJECTIVE: The Human Acellular Vessel (HAV) is a novel, off-the-shelf biologic conduit being evaluated for arterial reconstructions. Regulatory studies in peripheral arterial disease (PAD) to date have consisted of single-arm cohorts with no comparator groups to contrast performance against established standards. This study aimed to compare outcomes of the HAV with autologous great saphenous vein (GSV) in patients with advanced PAD undergoing infrageniculate bypass. METHODS: Patients with advanced PAD and no autologous conduit who underwent bypass with the 6-mm diameter HAV (Group 1; n = 34) (March 2021-February 2024) were compared with a multicenter historical cohort who had bypass with single-segment GSV (group 2; n = 88) (January 2017-December 2022). The HAV was used under an Investigational New Drug protocol issued by the Food and Drug Administration (FDA) under the agency's Expanded Access Program. RESULTS: Demographics were comparable between groups (mean age 69 ± 10 years; 71% male). Group 1 had higher rates of tobacco use (37 pack-years vs 28 pack-years; P = .059), coronary artery disease (71% vs 43%; P = .007), and prior coronary artery bypass grafting (38% vs 14%; P = .003). Group 1 had more patients classified as wound, ischemia, and foot infection clinical stage 4 (56% vs 33%; P = .018) and with previous index leg revascularizations (97% vs 53%; P < .001). Both groups had a similar number of patients with chronic limb-threatening ischemia (Rutherford class 4-6) (88% vs 86%; P = .693) and Global Anatomic Staging System stage III (91% vs 96%; P = .346). Group 1 required a composite conduit (two HAV sewn together) in 85% of bypasses. The tibial vessels were the target in 79% of group 1 and 100% of group 2 (P < .001). Group 1 had a lower mean operative time (364 minutes vs 464 minutes; P < .001). At a median of 12 months, major amputation-free survival (73% vs 81%; P = .55) and overall survival (84% vs 88%; P = .20) were comparable. Group 1 had lower rates of primary patency (36% vs 50%; P = .044), primary-assisted patency (45% vs 72%; P = .002), and secondary patency (64% vs 72%; P = .003) compared with group 2. CONCLUSIONS: Implanted under Food and Drug Administration Expanded Access provisions, the HAV was more likely to be used in redo operations and cases with more advanced limb ischemia than GSV. Despite modest primary patency, the HAV demonstrated resilience in a complex cohort with no autologous conduit options, achieving good secondary patency and providing major amputation-free survival comparable with GSV at 12 months.

Influence of Substrate Structure and Associated Properties on Endothelial Cell Behavior in the Context of Behaviors Associated with Laminar Flow Conditions.

In order to treat most vascular diseases, arterial grafts are commonly employed for replacing small-diameter vessels, yet they often cause thrombosis. The growth of endothelial cells along the interior surfaces of these grafts (substrates) is critical to mitigate thrombosis. Typically, endothelial cells are cultured inside these grafts under laminar flow conditions to emulate the native environment of blood vessels and produce an endothelium. Alternatively, the substrate structure could have a similar influence on endothelial cell behavior as laminar flow conditions. In this study, we investigated whether substrates with aligned fiber structures could induce responses in human umbilical vein endothelial cells (HUVECs) akin to those elicited by laminar flow. Our observations revealed that HUVECs on aligned substrates displayed significant morphological changes, aligning parallel to the fibers, similar to effects reported under laminar flow conditions. Conversely, HUVECs on random substrates maintained their characteristic cobblestone appearance. Notably, cell migration was more significant on aligned substrates. Also, we observed that while vWF expression was similar between both substrates, the HUVECs on aligned substrates showed more expression of platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31), laminin, and collagen IV. Additionally, these cells exhibited increased gene expression related to critical functions such as proliferation, extracellular matrix production, cytoskeletal reorganization, autophagy, and antithrombotic activity. These findings indicated that aligned substrates enhanced endothelial growth and behavior compared to random substrates. These improvements are similar to the beneficial effects of laminar flow on endothelial cells, which are well-documented compared to static or turbulent flow conditions.

Characteristics and Outcome of Vascular Graft Infections: A Risk Factor and Survival Analysis.

Background: Vascular graft infection (VGI) is a serious complication after implantation of arterial vascular grafts. Optimal surgical and pathogen-specific antimicrobial treatment regimens for VGI are largely unknown. We evaluated patients with arterial VGI according to onset, location, microbiological and imaging characteristics, and surgical and antimicrobial treatment and performed an outcome evaluation. Methods: Consecutive patients with VGI treated in 2 hospitals from 2010 through 2020 were retrospectively analyzed. Uniform definition criteria and standardized outcome evaluation were applied. Logistic regression was used for multiple analysis; survival analysis was performed with Kaplan-Meier analysis and a log-rank test. Results: Seventy-eight patients with VGI were included: 30 early-onset cases (<8 weeks after graft implantation) and 48 late-onset cases, involving 49 aortic and 29 peripheral grafts. The median time from initial implantation to diagnosis of VGI was significantly longer in aortic than peripheral VGIs (363 vs 56 days, P = .018). Late-onset VGI (odds ratio [OR], 7.3; P = .005) and the presence of surgical site infection/complication (OR, 8.21; P = .006) were independent risk factors for treatment failure. Surgical site infection/complication was associated with a higher risk for early-onset VGI (OR, 3.13; P = .040). Longer infection-free survival was observed in cases where the infected graft was surgically removed (P = .037). Conclusions: This study underlines the importance of timely diagnosis of VGI and preventing surgical site infections/complications at graft implantation. It highlights the complexity of infection eradication, especially for late-onset infections, and the importance of adequate antimicrobial and surgical treatment.

Artificial Neutrophils Against Vascular Graft Infection.

Efficient neutrophil migration to infection sites plays a vital role in the body's defense against bacterial infections and natural immune responses. Neutrophils have a short lifespan and cannot be mass-cultured in vitro. Therefore, developing more stable artificial neutrophils (AN) in a controllable manner has become a research focus. However, existing AN lack chemotaxis, which is the ability to migrate toward high-signal-concentration positions in a dynamic blood- flow environment. Supplying AN with chemotaxis is key to designing AN that are more similar to natural neutrophils in terms of morphology and function. In this study, micrometer-sized, spherical, biocompatible AN are developed. These AN consist of zeolitic imidazolate framework-8 nanoparticles encapsulating two enzymes, coacervate droplet frameworks, and outer phospholipid bilayers carrying enzymes. The AN exhibit responsiveness to elevated hydrogen peroxide levels at inflammation sites, actively chemotaxing toward these sites along concentration gradients. They also demonstrate effective combat against Staphylococcus aureus infections. The capabilities of the AN are further validated through in vitro experiments and in vivo evaluations using vascular graft infection models. This study replicates natural neutrophils in terms of chemical composition, functionality, and physiological impact. It introduces new ideas for advancing the development of advanced artificial cells.

A Comparison of Three-Layer and Single-Layer Small Vascular Grafts Manufactured via the Roto-Evaporation Method.

This study used the roto-evaporation technique to engineer a 6 mm three-layer polyurethane vascular graft (TVG) that mimics the architecture of human coronary artery native vessels. Two segmented polyurethanes were synthesized using lysine (SPUUK) and ascorbic acid (SPUAA), and the resulting materials were used to create the intima and adventitia layers, respectively. In contrast, the media layer of the TVG was composed of a commercially available polyurethane, Pearlbond 703 EXP. For comparison purposes, single-layer vascular grafts (SVGs) from individual polyurethanes and a polyurethane blend (MVG) were made and tested similarly and evaluated according to the ISO 7198 standard. The TVG exhibited the highest circumferential tensile strength and longitudinal forces compared to single-layer vascular grafts of lower thicknesses made from the same polyurethanes. The TVG also showed higher suture and burst strength values than native vessels. The TVG withstood up to 2087 ± 139 mmHg and exhibited a compliance of 0.15 ± 0.1%/100 mmHg, while SPUUK SVGs showed a compliance of 5.21 ± 1.29%/100 mmHg, akin to coronary arteries but superior to the saphenous vein. An indirect cytocompatibility test using the MDA-MB-231 cell line showed 90 to 100% viability for all polyurethanes, surpassing the minimum 70% threshold needed for biomaterials deemed cytocompatibility. Despite the non-cytotoxic nature of the polyurethane extracts when grown directly on the surface, they displayed poor fibroblast adhesion, except for SPUUK. All vascular grafts showed hemolysis values under the permissible limit of 5% and longer coagulation times.

Design and Synthesis of P(AAm-co-NaAMPS)-Alginate-Xanthan Hydrogels and the Study of Their Mechanical and Rheological Properties in Artificial Vascular Graft Applications.

Cardiovascular diseases (CVDs) are the number one cause of mortality among non-communicable diseases worldwide. Expanded polytetrafluoroethylene (ePTFE) is a widely used material for making artificial vascular grafts to treat CVDs; however, its application in small-diameter vascular grafts is limited by the issues of thrombosis formation and intimal hyperplasia. This paper presents a novel approach that integrates a hydrogel layer on the lumen of ePTFE vascular grafts through mechanical interlocking to efficiently facilitate endothelialization and alleviate thrombosis and restenosis problems. This study investigated how various gel synthesis variables, including N,N'-Methylenebisacrylamide (MBAA), sodium alginate, and calcium sulfate (CaSO4), influence the mechanical and rheological properties of P(AAm-co-NaAMPS)-alginate-xanthan hydrogels intended for vascular graft applications. The findings obtained can provide valuable guidance for crafting hydrogels suitable for artificial vascular graft fabrication. The increased sodium alginate content leads to increased equilibrium swelling ratios, greater viscosity in hydrogel precursor solutions, and reduced transparency. Adding more CaSO4 decreases the swelling ratio of a hydrogel system, which offsets the increased swelling ratio caused by alginate. Increased MBAA in the hydrogel system enhances both the shear modulus and Young's modulus while reducing the transparency of the hydrogel system and the pore size of freeze-dried samples. Overall, Hydrogel (6A12M) with 2.58 mg/mL CaSO4 was the optimal candidate for ePTFE-hydrogel vascular graft applications due to its smallest pore size, highest shear storage modulus and Young's modulus, smallest swelling ratio, and a desirable precursor solution viscosity that facilitates fabrication.

Hybrid Materials for Vascular Applications: A Preliminary In Vitro Assessment.

The production of biomedical devices able to appropriately interact with the biological environment is still a great challenge. Synthetic materials are often employed, but they fail to replicate the biological and functional properties of native tissues, leading to a variety of adverse effects. Several commercial products are based on chemically treated xenogeneic tissues: their principal drawback is due to weak mechanical stability and low durability. Recently, decellularization has been proposed to bypass the drawbacks of both synthetic and biological materials. Acellular materials can integrate with host tissues avoiding/mitigating any foreign body response, but they often lack sufficient patency and impermeability. The present paper investigates an innovative approach to the realization of hybrid materials that combine decellularized bovine pericardium with polycarbonate urethanes. These hybrid materials benefit from the superior biocompatibility of the biological tissue and the mechanical properties of the synthetic polymers. They were assessed from physicochemical, structural, mechanical, and biological points of view; their ability to promote cell growth was also investigated. The decellularized pericardium and the polymer appeared to well adhere to each other, and the two sides were distinguishable. The maximum elongation of hybrid materials was mainly affected by the pericardium, which allows for lower elongation than the polymer; this latter, in turn, influenced the maximum strength achieved. The results confirmed the promising features of hybrid materials for the production of vascular grafts able to be repopulated by circulating cells, thus, improving blood compatibility.

Dalbavancin as suppressive therapy for implant-related infections: a case series with therapeutic drug monitoring and review of the literature.

Implant-related infections may need suppressive antibiotic therapy (SAT). We describe a SAT strategy using dalbavancin with therapeutic drug monitoring (TDM). This is a retrospective bicentric study of patients with implant-related infection who received dalbavancin SAT between January 2021 and September 2023. Fifteen patients were included. Median number of injections was 4 (IQR: 2-7). Median time between two reinjections was 57 days (IQR 28-82). Dalbavancin plasma concentrations were above 4 mg/L for 97.9% of dosages (93/95) and above 8 mg/L for 85% (81/95). These results support the use of dalbavancin SAT for implant-related infections.

Evaluation of the Patients with Recurrent Angina After Coronary Artery Bypass Grafting.

INTRODUCTION: In this study, we aimed to evaluate the most common causes of recurrent angina after coronary artery bypass grafting (CABG) and our treatment approaches applied in these patients. METHODS: We included all patients who underwent CABG, with or without percutaneous coronary intervention after CABG, at our hospital from September 2013 to December 2019. Patients were divided into two groups according to the time of onset of anginal pain after CABG. Forty-five patients (58.16 ± 8.78 years) had recurrent angina in the first postoperative year after CABG and were specified as group I (early recurrence). Group II (late recurrence) comprised 82 patients (58.05 ± 8.95 years) with angina after the first year of CABG. RESULTS: The mean preoperative left ventricular ejection fraction was 53.22 ± 8.87% in group I, and 54.7 ± 8.58% in group II (P=0.38). No significant difference was registered between groups I and II regarding preoperative angiographic findings (P>0.05). Failed grafts were found in 27.7% (n=28/101) of the grafts in group I as compared to 26.8% (n=51/190) in group II (P>0.05). Twenty-four (53.3%) patients were treated medically in group I, compared with 54 (65.8%) patients in group II (P=0.098). There was a need for intervention in 46.6% (n=21) of group I patients, and in 34.1% (n=28) of group II patients. CONCLUSION: Recurrent angina is a complaint that should not be neglected because most of the patients with recurrent angina are diagnosed with either native coronary or graft pathology in coronary angiography performed.

Small diameter vascular grafts: progress on electrospinning matrix/stem cell blending approach.

The exploration of the next-generation small diameter vascular grafts (SDVGs) will never stop until they possess high biocompatibility and patency comparable to autologous native blood vessels. Integrating biocompatible electrospinning (ES) matrices with highly bioactive stem cells (SCs) provides a rational and promising solution. ES is a simple, fast, flexible and universal technology to prepare extracellular matrix-like fibrous scaffolds in large scale, while SCs are valuable, multifunctional and favorable seed cells with special characteristics for the emerging field of cell therapy and regenerative medicine. Both ES matrices and SCs are advanced resources with medical application prospects, and the combination may share their advantages to drive the overcoming of the long-lasting hurdles in SDVG field. In this review, the advances on SDVGs based on ES matrices and SCs (including pluripotent SCs, multipotent SCs, and unipotent SCs) are sorted out, and current challenges and future prospects are discussed.

Recent Advances in the Fabrication and Performance Optimization of Polyvinyl Alcohol Based Vascular Grafts.

Cardiovascular disease is one of the diseases with the highest morbidity and mortality rates worldwide, and coronary artery bypass grafting (CABG) is a fast and effective treatment. More researchers are investigating in artificial blood vessels due to the limitations of autologous blood vessels. Despite the availability of large-diameter vascular grafts (Ø > 6 mm) for clinical use, small-diameter vascular grafts (Ø < 6 mm) have been a challenge for researchers to overcome in recent years. Vascular grafts made of polyvinyl alcohol (PVA) and PVA-based composites have excellent biocompatibility and mechanical characteristics. In order to gain a clearer and more specific understanding of the progress in PVA vascular graft research, particularly regarding the preparation methods, principles, and functionality of PVA vascular graft, this article discusses the mechanical properties, biocompatibility, blood compatibility, and other properties of PVA vascular graft prepared or enhanced with different blends using various techniques that mimic natural blood vessels. The findings reveal the feasibility and promising potential of PVA or PVA-based composite materials as vascular grafts.

Design and fabrication of dual-layer PCL nanofibrous scaffolds with inductive influence on vascular cell responses.

Confronted with the profound threat of cardiovascular diseases to health, vascular tissue engineering presents potential beyond the limitations of autologous and allogeneic grafts, offering a promising solution. This study undertakes an initial exploration into the impact of a natural active protein, elastin, on vascular cell behavior, by incorporating with polycaprolactone to prepare fibrous tissue engineering scaffold. The results reveal that elastin serves to foster endothelial cell adhesion and proliferation, suppress smooth muscle cell proliferation, and induce macrophage polarization. Furthermore, the incorporation of elastin contributes to heightened scaffold strength, compliance, and elongation, concomitantly lowering the elastic modulus. Subsequently, a bilayer oriented polycaprolactone (PCL) scaffold infused with elastin is proposed. This design draws inspiration from the cellular arrangement of native blood vessels, leveraging oriented fibers to guide cell orientation. The resulting fiber scaffold exhibits commendable mechanical properties and cell infiltration capacity, imparting valuable insights for the rapid endothelialization of vascular scaffolds.

Transformation of metallo-elastomer grafts in a carotid artery interposition model over a year.

Current vascular grafts, primarily Gore-Tex® and Dacron®, don't integrate with the host and have low patency in small-diameter vessels (<6 mm). Biomaterials that possess appropriate viscoelasticity, compliance, and high biocompatibility are essential for their application in small blood vessels. We have developed metal ion crosslinked poly(propanediol-co-(hydroxyphenyl methylene)amino-propanediol sebacate) (M-PAS), a biodegradable elastomer with a wide range of mechanical properties. We call these materials metallo-elastomers. An initial test on Zn-, Fe-, and Cu-PAS grafts reveals that Cu-PAS is the most suitable because of its excellent elastic recoil and well-balanced polymer degradation/tissue regeneration rate. Here we report host remodeling of Cu-PAS vascular grafts in rats over one year. 76 % of the grafts remain patent and >90 % of the synthetic polymer is degraded by 12 months. Extensive cell infiltration leads to a positive host remodeling. The remodeled grafts feature a fully endothelialized lumen. Circumferentially organized smooth muscle cells, elastin fibers, and widespread mature collagen give the neoarteries mechanical properties similar to native arteries. Proteomic analysis further reveals the presence of important vascular proteins in the neoarteries. Evidence suggests that Cu-PAS is a promising material for engineering small blood vessels.

An ex vivo study of infections of vascular grafts and endografts with scanning electron microscopy.

OBJECTIVE: Vascular graft and endograft infections (VGEIs) are complicated by high morbidity, mortality, and recurrence rates, notably due to biofilm formation on the graft surface, hardly dislodgeable by the sole anti-infectious treatment. The characteristics of this biofilm are still poorly documented. The aim of this study was to evaluate ex vivo biofilm on removed infected vascular grafts and endografts (VGEs). METHODS: Explanted VGEs were prospectively collected from 2019 to 2022 at Bordeaux University Hospital, France. Two samples per graft were used for scanning electron microscopy imaging; one was sonicated, and both grafts' sides were imaged. RESULTS: A total of 26 patients were included, 18 with VGEI, eight without any infection (endoleak and/or thrombosis), and 29 VGEs were collected. Microbial documentation was obtained in 83% of VGEIs. A thick layer of fibrin was visible on almost all grafts, mixed with a dense biofilm matrix on infected grafts visible as early as 1 month after the onset of infection. Bacteria were not always visualized on infected grafts' surface (80% on outer side and 85% on luminal side) but were surprisingly present on one-third of non-infected grafts. There was no significant difference between biofilm, fibrin, and microorganisms' distribution between the two grafts' sides. However, there were clear differences between infected and non-infected grafts, since immune cells, bacteria and biofilm were more frequently visualized on both sides of infected grafts (P < .05). Bacteria and immune cells although still visible, were significantly less present after sonication; the number of other elements including biofilm was not significantly different. CONCLUSIONS: The persistence of a thick layer of fibrin and biofilm embedding microorganisms on both sides of infected VGE even after 1 month of infection could be the explanation for the low success rates of conservative management and the usual need for graft removal to treat VGEIs.