Prosthetic Vascular Graft Research Articles

Reconstruction of a Prosthetic Vascular Graft Infections in the Femoral Region with Gracilis and Sartorius Muscle Flaps

Reconstruction of a Prosthetic Vascular Graft Infections in the Femoral Region with Gracilis and Sartorius Muscle Flaps

Sigmoid Perforation Caused by an Aortobifemoral Vascular Graft

An 83-year-old man underwent aortobifemoral bypass graft surgery for an abdominal aortic aneurysm. Ten days after his discharge he was readmitted with fever and signs of infection. A computed tomography scan revealed sigmoid diverticulosis, a perigraft collection containing gas bubbles near the aortic anastomosis and smaller localized collections near the iliac vessels. He was started on antibiotics but a day later he developed hematochezia. A sigmoidoscopy was performed, which revealed a prosthetic vascular graft penetrating “through and through” the sigmoid colon (Figures A–C) with active bleeding at 1 site of the perforation (Figure D, arrow). The patient underwent a partial left colectomy of the involved sigmoid with a primary anastomosis, and explantation and replacement of the aortobifemoral graft. Postoperatively, he was transferred to the intensive care unit but unfortunately died 10 days later because of septic complications.

The giant staphylococcal protein Embp facilitates colonization of surfaces through Velcro-like attachment to fibrillated fibronectin

Staphylococcus epidermidis causes some of the most hard-to-treat clinical infections by forming biofilms: Multicellular communities of bacteria encased in a protective matrix, supporting immune evasion and tolerance against antibiotics. Biofilms occur most commonly on medical implants, and a key event in implant colonization is the robust adherence to the surface, facilitated by interactions between bacterial surface proteins and host matrix components. S. epidermidis is equipped with a giant adhesive protein, extracellular matrix-binding protein (Embp), which facilitates bacterial interactions with surface-deposited, but not soluble fibronectin. The structural basis behind this selective binding process has remained obscure. Using a suite of single-cell and single-molecule analysis techniques, we show that S. epidermidis is capable of such distinction because Embp binds specifically to fibrillated fibronectin on surfaces, while ignoring globular fibronectin in solution. S. epidermidis adherence is critically dependent on multivalent interactions involving 50 fibronectin-binding repeats of Embp. This unusual, Velcro-like interaction proved critical for colonization of surfaces under high flow, making this newly identified attachment mechanism particularly relevant for colonization of intravascular devices, such as prosthetic heart valves or vascular grafts. Other biofilm-forming pathogens, such as Staphylococcus aureus, express homologs of Embp and likely deploy the same mechanism for surface colonization. Our results may open for a novel direction in efforts to combat devastating, biofilm-associated infections, as the development of implant materials that steer the conformation of adsorbed proteins is a much more manageable task than avoiding protein adsorption altogether.

Human Thrombin–Gelatin Matrix With Rifampin: A Novel Technique for Treating Vascular Graft Infections

Approximately 1% to 6% of prosthetic vascular grafts will be complicated by infection. However, the mortality rates have ranged from 17% to 40%, and the morbidity is also high, including reinfection rates reported at 18% and limb loss close to 11%. Early aggressive surgical management, including graft excision and wide wound debridement with extra-anatomic bypass creation is the reference standard. Graft preservation techniques have been increasingly used, with high cure rates. Muscle flap, coverage, and antibiotic-coated absorbable and nonabsorbable beads have been reported to provide high cure rates but with associated technical difficulties and suboptimal graft salvage rates. We implemented a novel technique for localized antibiotic therapy using a human thrombin–gelatin matrix with rifampin (HTGM+R) at our institution for the past 5 years (Figs 1 and 2). We have described the rates of graft salvage, reintervention, limb salvage, and infection recurrence. We performed a retrospective cohort study of patients who had presented with prosthetic vascular graft infection from January 2016 through June 2021 and had been treated using our novel technique. Statistical analysis included descriptive frequencies of the demographic variables and outcomes of interest. A total number of 16 patients with a total of 32 interventions were included in the present study. Approximately 76.5% had required two or more interventions. HGTM+R was used for 15 interventions (46.9%) in 14 patients. Thrombectomy was the second most common intervention (n = 11; 34.4%). The mean age was 65.2 years, and the mean body mass index was 26.7 kg/m2. The common comorbidities are shown in the Table. The graft salvage rate was 80%, the limb salvage rate was 93.3%, and the freedom from infection rate was 86.7% for HGTM+R. However, the reintervention rate was 28.6%. Only four patients had required graft excision at an average follow-up of 12 months. Hypertension was the most common comorbidity, followed by diabetes and steroid use. Finally, no association with specific bacteria was seen. To date and to the best of our knowledge, the present study is the only study to describe this novel technique for treating prosthetic vascular graft infections. Moreover, it is the only study to describe the outcomes of HGTM+R in the treatment of prosthetic vascular graft infection.Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Human Thrombin–Gelatin Matrix With Rifampin: Novel Technique for Treating Vascular Graft Infections

Approximately 1% to 6% of prosthetic vascular grafts will be complicated by infections. However, the mortality rates range from 17% to 40%, and morbidity is also high, including reinfection rates reported at 18% and limb loss close to 11%. Early aggressive surgical management, including graft excision and wide wound debridement with extra-anatomic bypass creation is the reference standard. Graft preservation techniques have been increasingly used, with high cure rates. Muscle flap, coverage, and antibiotic-coated absorbable and nonabsorbable beads have been reported to provide high cure rates but, owing to the associated technical difficulties, with suboptimal graft salvage rates.

Total arch replacement: When and how?

Acute type A aortic dissection (ATAAD) is a life-threatening disease, which often causes cardiac tamponade, rupture, and malperfusion. ATAAD is associated with a high hospital mortality rate. Open aortic surgery for ATAAD is always required to save the patient, particularly elderly patients. Tear-oriented surgery is recommended as the frontline treatment for ATAAD, and hemiarch replacement (HAR) is sufficient because the primary entry is often observed in the ascending aorta (60%-70%). However, HAR has some drawbacks, such as new creation of an anastomotic entry and unfavorable distal aortic remodeling during long-term follow-up. Although total arch replacement (TAR) is a demanding procedure, it is another useful option for ATAAD. Proper patient selection for TAR is controversial. Standardized procedure for TAR, including the optimal brain protection methods and the use of excellent sealed vascular prosthetic grafts, has been established over the past decades. Therefore, TAR is increasingly being selected for HAR in patients who are young or have enlarged aortic arch, severely dissected supra-aortic arch vessels, or hereditary thoracic aortic disorders. The emerging technology of commercially available frozen elephant trunk accelerated the application of TAR, facilitates distal anastomosis, and improves distal aortic remodeling. Although further evidence is required, TAR could be the best choice for HAR for selected patients. Currently, appropriate selection of the surgical technique is important to maximize the benefits of open surgery for ATAAD.

Repeated prosthetics of the ascending aorta and aortic arch with a homograft for prosthesis infection and ruptured aorta after Bentalla de Bono operation

Prosthetic vascular graft infection is a formidable complication after cardiac surgery. Until now, the question on the tactics of managing such patients remains open, as well as the timing of each of the treatment methods such as conservative antibiotic therapy and surgery. In addition, the choice of a method of surgical treatment in itself poses new questions for specialists in regard to what methods to adhere to including prosthesis-preserving technique, prosthesis explantation and its replacement with a synthetic or biological graft, and the use of omentum to cover the infected bed. We present a case of treating a patient with an infected synthetic valve-containing conduit after Bentall de Bono operation and aortic rupture with the formation of false aneurysms. Attention is drawn to the prolonged clinical patient condition manifesting with fever, and the lack of data suggesting an infectious process according to positron-emission tomography and blood cultures. We chose a homograft of the ascending aortic and aortic arch with aortic valve as a conduit. It is also of interest that cultures of infectious prosthesis and aortic valve did not reveal any infectious agent. Aggressive antibiotic therapy in combination with surgical replacement of the infected prosthesis with a cryoprepared allograft allowed for successful treatment of patient without complications.

Methicillin‑sensitive Staphylococcus aureus prosthetic vascular graft infection after a Fontan procedure in an adult patient: A case report

Heart infections are not limited to infectious endocarditis. In fact, prosthetic vascular graft infections are among the most severe complications associated with vascular and cardiac surgery. The risk of developing an infection on prosthetic material is estimated to be ~5%. The mortality rate associated with the infection is estimated to be ~10‑25% within 30 days of infection and 50% after 1 year. The present article describes a case of a methicillin‑sensitive <em>Staphylococcus aureus</em> (MSSA) infection on the prosthetic material following a heart Fontan procedure. To the best of our knowledge, only one other case of extracardiac prosthesis‑related infection following Fontan surgery has been reported to date in adults. Prosthetic vascular graft infections (PVGIs) are a rare complication of heart surgery. However, PVGIs can seldomly occur and are burdened by a decreased survival rate. Therefore, physicians need to promptly suspect and recognize such cases. Further studies are required however, in order to determine the feasibility and long‑term survival rates of a conservative therapeutic approach.

The Impact of Seasonality on Prosthetic Arteriovenous Vascular Access Graft Thrombosis

Highlights Abstract Introduction: Arteriovenous prosthetic grafts are susceptible to recurrent thrombotic occlusions mainly due to venous outflow disease secondary to neointimal hyperplasia. Maintenance of vascular access for dialysis is a perpetual challenge for both patients and health care systems. In regions with hotter climates, there is a clinical impression that episodes of prosthetic arteriovenous vascular access graft thrombosis are more frequent during hot dry summers secondary to dehydration and increased blood viscosity. Seasonality of thrombotic events has been observed in multiple vascular beds. However, a seasonal pattern or any association of arteriovenous graft thrombosis with temperature and relative humidity levels has never been fully demonstrated. Methods: Data were collected prospectively from January 2014 until December 2020 but analyzed retrospectively. In this 7-year timeframe, 289 episodes of arteriovenous graft thrombosis were identified from 142 grafts fashioned. Results: No monthly variation (P = 0.35) or seasonal variation (P = 0.91) was identified. No statistically significant correlation between episodes of thrombosis and mean monthly temperature and mean relative humidity was noted. Conclusion: No evidence was identified to support this theory. However, multiple issues with assessments of events must be conceded. Graft thrombosis is multifactorial in nature, and venous outflow disease contributes toward a significant number of these events. Within our local cohort, a low primary patency rate was identified, which further contributes to graft interventions. Relatively small numbers were recruited, and therefore, potential correlations could have been missed.

Comparison of the Bifurcated Graft Reconstruction and Aortic Stump Closure in Open Surgical Conversion After Endovascular Aneurysm Repair

The optimal management of the aortic stump in open surgical conversion (OSC) after Abdominal aortic aneurysm (AAA) endovascular aneurysm repair (EVAR) is debated. Therefore, we aimed to compare the efficacies and safety between the bifurcated prosthetic vascular graft in situ stump reconstruction (p-graft ISSR) and aortic stump closure (ASC) in OSC. We analyzed 973 elective AAA patients admitted from January 01, 2001 to December 31, 2020, at the First Affiliated Hospital of Sun Yat-sen University. We conducted a statistical analysis of the clinical characteristics, procedural data, as well as outcomes and technique considerations of aortic stump management in OSC patients. A total of 24 male patients had OSC after EVAR. The rate of stent graft infection was 54.17% before OSC. Eleven patients underwent ASC, and 13 patients were treated with p-graft ISSR. The major complication after OSC was aortic stump bleeding (total incidence was 37.50%) (1 patient with a periaortic hematoma and 8 patients with a stump blowout). The total incidences of stump blowout between the patients with ASC and those with p-graft ISSR were significantly different (45.45% vs. 23.08%, P < 0.05). The total perioperative mortality was 25.00% (6 patients with stump blowouts). The perioperative survival rates between these 2 aortic stump management approaches were 72.72% and 76.92% (ASC vs. p-graft ISSR, P < 0.05). In total, 18 patients were followed up (3-180 months). There were 3 aorta-related deaths during the late follow-up period (including both of the 2 stump-blowout-related deaths just treated with ASC). If the condition of the aorta and peri-aortic tissue are suitable for a prosthetic graft bypass, the p-graft ISSR is highly recommended for OSC patients after EVAR.

DISPARITIES IN 5-YEAR RELATIVE SURVIVAL FOR EARLY ONSET COLORECTAL CANCER

Prosthetic vascular graft procedures are a common treatment modality for peripheral vascular disease. A relatively common complication is graft infection, occurring at a rate of 0.5–5%. When they occur, graft infections are associated with significant morbidity and mortality. Vascular graft infections also represent a diagnostic and therapeutic challenge for the physicianHere, we report a case where the rare finding of secondary hypertrophic osteoarthropathy was an important indication of underlying aortic graft infection that was initially misdiagnosed. A review of the literature revealed 34 cases of vascular graft infection associated with hypertrophic osteoarthropathy.The mean interval from surgery to time of infection was approximately 5 years. Mortality was 35%. When combined with hypertrophic osteoarthropathy, vascular graft infection was complicated by an aortoenteric fistula in 53% of the cases.The complexity of this case highlights the challenges physicians face in order to diagnose and treat this condition.

The application of tissue-engineered fish swim bladder vascular graft

Small diameter (< 6 mm) prosthetic vascular grafts continue to show very low long-term patency, but bioengineered vascular grafts show promising results in preclinical experiments. To assess a new scaffold source, we tested the use of decellularized fish swim bladder as a vascular patch and tube in rats. Fresh goldfish (Carassius auratus) swim bladder was decellularized, coated with rapamycin and then formed into patches or tubes for implantation in vivo. The rapamycin-coated patches showed decreased neointimal thickness in both the aorta and inferior vena cava patch angioplasty models. Rapamycin-coated decellularized swim bladder tubes implanted into the aorta showed decreased neointimal thickness compared to uncoated tubes, as well as fewer macrophages. These data show that the fish swim bladder can be used as a scaffold source for tissue-engineering vascular patches or vessels.

Antimicrobial vascular grafts: experimental development and implementation in clinical practice

Prosthetic vascular graft infections, followed by severe complications and high mortality rates, remain one of the main issues in cardiovascular surgery. Therefore, the development of antimicrobial coating for vascular prostheses that is capable of preventing the infection is a very relevant field. This review outlines the main factors of development of antibiotic-resistant bacteria, the main directions in the development of vascular prostheses with an antimicrobial coating, and the prospects for the application of antimicrobial peptides and cationic amphiphiles as antimicrobial coating to develop an infection-resistant vascular prosthesis.

A Radiation-Crosslinked Gelatin Hydrogel That Promotes Tissue Incorporation of an Expanded Polytetrafluoroethylene Vascular Graft in Rats.

A prosthetic vascular graft that induces perigraft tissue incorporation may effectively prevent serious sequelae such as seroma formation and infection. Radiation-crosslinked gelatin hydrogel (RXgel) mimics the chemical and physical properties of the in vivo extracellular matrix and may facilitate wound healing by promoting tissue organization. Fibroblasts cultured on RXgel actively migrated into the gel for up to 7 days. RXgels of three different degrees of hardness (Rx[10], soft; Rx[15], middle; Rx[20], hard) were prepared, and small disc-like samples of RXgels were implanted into rats. In vitro and in vivo results indicated that Rx[10] was too soft to coat vascular grafts. Thus, expanded polytetrafluoroethylene (ePTFE) vascular grafts coated with RXgel were developed using Rx[15] and Rx[20] gels, and ring-shaped slices of the graft were implanted into rats. Alpha-smooth muscle actin (αSMA) and type III collagen (Col-III) levels were detected by immunohistochemistry. Immunohistochemical staining for αSMA and Col-III demonstrated that RXgel-coated vascular grafts induced more granulation tissue than non-coated grafts on days 14 and 28 after implantation. RXgel-coated ePTFE vascular grafts may provide a solution for patients by reducing poor perigraft tissue incorporation.

Prosthetic vascular graft infection: A systematic review and meta-analysis on diagnostic accuracy of 18FDG PET/CT.

There is a high risk of mortality and morbidity associated with Vascular Graft Infections (VGI) which requires early diagnosis. The aim of the present systematic review and meta-analysis was to evaluate the diagnostic accuracy, sensitivity and specificity of 18FDG PET/CT in diagnosing VGI. A systematic review was conducted according to the PRISMA guidelines through a search in Embase, PubMed, and Cochrane databases. We evaluated five parameters including specificity, sensitivity, negative and positive predictive values (NPV and PPV), and accuracy. We used STATA/MP 15.0 (StataCorp, College Station, TX) for all of our analyses. Overall 10 studies including 320 patients undergone 18FDG PET/CT were included. The sensitivity, specificity, positive and negative likelihood ratios along with their 95% CI were 0.92 (95% CI 0.88-0.95), 0.76 (95% CI 0.76-0.70), 3.49 (95% CI 3.49-2.32) and 0.14 (95% CI 0.09-0.23), respectively. The diagnostic odds ratio (DOR) for diagnosis of VGI was 37.12 (95% CI 14.84-92.82). The mean cut-off value of the maximum standardized uptake value (SUVmax) for diagnosis of VGI was 5.39 while the overall mean SUVmax among patients with VGI was 8.47. According to our results, 18FDG PET/CT is a useful diagnostic method in detecting active VGI with high diagnostic accuracy. Because of its ability to evaluate morphology and main texture using SUVmax, the 18FDG PET/CT provides an objective assessment of aspects and extent of disease activity, which results in preventing unnecessary surgery, proper treatment planning, and evaluating the effectiveness of treatment.

Midterm outcome of biosynthetic collagen prosthesis for treating aortic and peripheral prosthetic graft infections.

To report the midterm outcomes of treating prosthetic peripheral and aortic graft infections using a biosynthetic collagen prosthesis in a tertiary vascular center. A retrospective analysis of all patients with prosthetic peripheral and aortic graft infections who underwent in situ reconstruction using a biosynthetic collagen prosthesis between March 2015 and November 2020 was conducted. Perioperative and midterm outcomes were analyzed. A biosynthetic collagen prosthesis was used in 19 patients (14 males, median age 66years) to reconstruct the femoral artery (n = 6), iliac artery (n = 1), and infrarenal aorta (n = 12). All patients were treated for a prosthetic vascular graft infection. The median follow-up period was 26.6months (range 1-66months). The 30-day graft failure rate was 15.7% (n = 3), leading to a major amputation in one patient (5.3%). All grafts were occluded aortofemoral reconstructions in patients with occluded superficial femoral artery and were treated by immediate thrombectomy. The 30-day mortality rate was 5.3% (n = 1), and survival after 3years was 63.2%. The reinfection rate was 5.3% (n = 1). At 13.6months, the occlusion of a femoral graft was detected in 5.3% (n = 1) and was treated with a new interposition graft. We observed no graft rupture or degeneration during follow-up. Although results of in situ repair with autologous vein seem to be superior with little or none reinfection and low number of occlusions, biosynthetic collagen prostheses show acceptable midterm outcomes in terms of graft occlusion and mortality after prosthetic peripheral and aortic graft infections. Similar to other xenogenous materials, the reinfection rate is low with this prosthesis. With regard to immediate availability and easy handling, the use of a biosynthetic collagen prosthesis might be favorable compared to other replacement materials while treating prosthetic graft infections.

New method of hepatic artery reconstruction after its injury or resection.

e16221 Background: Restoration the hepatic arterial blood flow is required in traumatic or iatrogenic damage to the hepatic artery and its branches, as well as in the planned resection of the hepatic artery with subsequent reconstruction. Various ways have been proposed to solve this problem: ligation of the hepatic artery and its branches, which is associated with an extremely high mortality rate, reaching 70%, and the need for extensive liver resections; portal vein arteriolization; transposition of the splenic artery with its severe complications (heart attack, abscess) or hepatic artery replacement sometimes are not available and imply aggressive anticoagulant therapy, which is often challenging after extensive oncological interventions. Prosthetic vascular grafts are associated with a high risk of infection. We propose replacement of the common hepatic artery defect by transposition of the left gastric artery and end-to-end anastomosis between the proximal end of the left gastric artery and the distal end of the hepatic artery. Methods: The proposed method was applied in 7 cancer patients - 4 cases of iatrogenic damage to the common hepatic artery in lymph node dissection of the hepatoduodenal ligament and 3 resection of the common hepatic artery with tumor infiltration. The mean age of patients was 53 years. 2 patients had surgery for gastric cancer, 5 - pancreatic cancer. Results: The vascular reconstruction lasted for 17 minutes. No thrombotic complications of the reconstruction area or liver necrosis in the postoperative period were registered. The main advantages of this method were the absence of synthetic materials or deficit blood supply to neighboring organs, and no need for extensive mobilization of the great vessels in other areas (renal artery, abdominal aorta). Conclusions: The proposed method for reconstruction of the hepatic artery allows performing a simple and adequate restoration of the hepatic arterial blood flow, reduced time of the vascular stage of the surgery and reduced incidence of postoperative complications associated with the vascular stage - reduced time of liver ischemia and reduced risk of thrombosis in the reconstruction area.

Stepwise immobilization of keratin-dopamine conjugates and gold nanoparticles on PET sheets for potential vascular graft with the catalytic generation of nitric oxide

Gold nanoparticles(AuNPs) are capable to catalyze the nitric oxide (NO) generation from endogenous and exogenous donors, thereby promoting re-endothelialization and inhibiting intimal hyperplasia and thrombosis. Herein, keratin-dopamine conjugates were synthesized and then immobilized on the surface of the pre-aminolyzed poly(ethylene terephthalate) (PET) via self-polymerization of dopamine residue, following by the formation of AuNPs in situ without extra reductant. The modified PET sheets(PET-AuNPs) could promote the growth of HUVECs while inhibit the proliferation of HUASMCs due to their catalytic generation of NO from GSNO. In addition, these sheets exhibited antibacterial properties and good blood compatibility without hemolysis. Taken together, this strategy for designing prosthetic vascular grafts to treat cardiovascular diseases has great potential.

Evaluation of the probe burst test as a measure of strength for a biologically-engineered vascular graft

Biologically-engineered vascular grafts have the potential to provide a viable alternative to donor vessels and synthetic grafts. In congenital heart defect patients, the need is even more dire since neither has the capacity to provide somatic growth. To ensure clinically-used grafts perform to accepted standards, mechanical strength is a crucial consideration, with burst testing being considered as one key metric. While ISO 7198 standards for prosthetic vascular grafts provide multiple choices for burst testing, most studies with tissue-engineered grafts have been performed with only pressure burst testing. Here, we compare the performance of a decellularized tube of collagenous matrix grown from dermal fibroblasts, possessing circumferential fiber alignment and anisotropic tensile properties, as determined from pressure and probe burst testing. The two burst tests showed a strong correlation with each other and with tensile strength. Further, relatively weak and strong batches of grafts showed commensurate differences in pressure and probe burst values. Both probe burst and tensile strength measurements in the central and edge regions of the grafts were similar in value, consistent with homogenous collagen content and microstructure throughout the grafts as indicated by histology, in contrast to ovine femoral and carotid arteries similarly tested. Finite element analysis of the probe burst test pre-failure for a homogeneous, isotropic approximation of the matrix constitutive behavior indicated dependence of the (inferred) effective failure stress achievable on probe diameter. The results indicate a probe burst test in a sampled edge region of this biologically-engineered graft provides a representative measure of burst strength of the entire graft.

Tissue engineering: Relevance to neonatal congenital heart disease

Congenital heart disease (CHD) represents a large clinical burden, representing the most common cause of birth defect-related death in the newborn. The mainstay of treatment for CHD remains palliative surgery using prosthetic vascular grafts and valves. These devices have limited effectiveness in pediatric patients due to thrombosis, infection, limited endothelialization, and a lack of growth potential. Tissue engineering has shown promise in providing new solutions for pediatric CHD patients through the development of tissue engineered vascular grafts, heart patches, and heart valves. In this review, we examine the current surgical treatments for congenital heart disease and the research being conducted to create tissue engineered products for these patients. While much research remains to be done before tissue engineering becomes a mainstay of clinical treatment for CHD patients, developments have been progressing rapidly towards translation of tissue engineering devices to the clinic.