Bovine Graft Research Articles

Bovine pericardial graft for revascularization of the lower limb following mycotic aneurysm complicating infective endocarditis

Mycotic aneurysm, which complicates 2.5%–10% of cases of infectious endocarditis, is an important cause of morbidity and mortality despite antibiotic therapy. Elective surgery remains the cornerstone of the treatment of mycotic aneurysms because of the major risk of rupture. For femoral arteries, the surgical treatment is based on the resection of the aneurysm, with revascularization of the territory downstream. The recommended materials for revascularizations are in the first place biological grafts such as veins grafts (great saphenous vein) and homograft. In our observation, faced with the small diameter of the internal saphenous vein and the lack of homograft availability, and considering the high risk of infection recurrence at the operating site, we opted for the confection of biological graft using bovine pericardium and we think that it will be more resistant to infection than prostheses. According to our knowledge, this technique has not been reported before in the literature, and the validation of this technique on a series of cases and in the long term is necessary.

Which Pulmonary Homograft to Use in Patients With Major Aortopulmonary Collateral Arteries and Pulmonary Hypertension?

The patient was a 19-year-old male who had complex congenital heart disease with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries (MAPCAS). He underwent serial unifocalisation of unilateral MAPCAS to pulmonary homograft tubes with arterial pulmonary shunt supply. Anatomical correction was achieved by removal of arterial shunts, application of a Dacron tube graft to the homograft tubes, which was connected to a 20-mm Hancock bioprosthesis pulmonary valve associated with ventricular septal defect closure at age 7 years. Later in life, he developed right pulmonary artery stenosis and pulmonary valve stenosis. Right pulmonary artery stenosis was treated with a tissue patch and balloon expandable stent. Pulmonary valve stenosis was treated with balloon dilatation. A subsequent attempt at right ventricular outflow tract (RVOT) reconstruction with a pulmonary homograft failed, due to suture line rupture secondary to high RV pressures (90/12 mmHg). This required emergent surgery for a RV-pulmonary artery conduit change with a 22-mm Contegra conduit. Major aortopulmonary collateral arteries is one of the most challenging conditions to manage. Reconstruction of the RVOT may require pulmonary valve replacement with a cryopreserved homograft or bovine jugular vein graft (Contegra) during primary repair or re-operation. One study showed that although survival and freedom from distal stenosis were similar between the two conduits, freedom from failure, dysfunction, and explantation were better with Contegra conduits in patients needing RVOT reconstruction. Furthermore, choice of RV-pulmonary artery conduit must take into account the pulmonary artery pressure, with a pulmonary homograft contraindicated with PAP >50 mmHg.

Histomorphometric Assessment of the Impact of Bovine Demineralized Bone Graft on Bone Healing Versus Autogenous, Allogeneic and Synthetic Grafts in Experimentally- Induced Critical Size Bone Defects in Rats

Aim: Bone tissue has the ability to heal itself (regeneration) and may restore its morphology and function when injured. However, healing may be limited in the case of large wounds. A “critical-size defect” is an intraosseous wound in a particular bone and species of animal that will not heal spontaneously morphologically and functionally during the lifetime of the animal. Autogenous bone grafts have been regarded as “gold standard” for treatment of critical-size bone defects. Known drawbacks of autogenous bone graft have led to research efforts focusing on different graft materials and resulted in several alternative substitutes including xenografts, allografts and synthetic graft materials. The aim of the present study was to perform a histomorphometric study to investigate the effect of bovine demineralized bone graft on bone healing in comparison to autogenous, allogeneic and synthetic graft materials when applied into critical size bone defects with a diameter of 5 mm. Materials and methods: Experimental animals were divided into 4 groups, each having 8 rats. In the control group, a mandibular defect was created and then filled with a bovine graft (Integros Bone Plus XS Adana/Turkey). In the experimental groups, autogenous bone was reinserted into the critical-size defect which was created using a trephine bur in Group I (autogenous group) and Group II received a human graft (Korea Bone Bank (KBB) Gasandong Keumcheongu Seoul/South Korea) to fill the critical-size defect. For Group III, a synthetic bone graft β-tricalcium phosphate (Cerasorb North Carolina/USA) was applied on the critical-size bone defect. Specimens were obtained for histomorphometric examination and rats were sacrificed on day 28. Results: Histomorphometric examination performed on day 28 to evaluate the relative effects of different graft materials on new bone formation showed no significant difference in the volume of newly formed bone between groups receiving autogenous bone graft, allograft and bovine xenograft but a significant difference was observed versus synthetic bone graft group. Conclusion: While autogenous bone graft is currently regarded as the gold standard for bone regeneration, the difficulties in harvesting and application of autografts limit their use. Our results demonstrate that bovine bone graft may be used as a safe and effective alternative to autogenous bone graft.

Biosynthetic vascular graft: a valuable alternative to traditional replacement materials for treatment of prosthetic aortic graft infection?

To report the experience of a tertiary vascular surgery center using Omniflow II® biosynthetic vascular grafts for treatment of prosthetic aortic graft infection. Retrospective analysis of all patients with prosthetic graft infections who underwent in situ aortic reconstruction using Omniflow II® grafts or other conduits between March 2015 and May 2017. Early and late mortality, perioperative complications, and reinfection rate were analyzed. Sixteen patients (14 males, median age 68.5, range 57-89) with prosthetic aortic graft infection were treated at our center. Eight patients received an Omniflow II® biosynthetic graft, two patients silver-triclosan coated grafts, three patients bovine pericardial tube grafts, and three patients composite bovine pericardial tube grafts with Omniflow II® graft extensions. Perioperative complications occurred in seven patients (43.8%). Early mortality rate was 18.7% (n = 3). In addition, four patients died during follow-up after a median of 11 months (range 0-34 months). We did not observe any reinfections. Bypass grafts were patent in all patients. No major limb amputations were performed during follow-up. Treatment of prosthetic aortic graft infection with Omniflow II® vascular grafts is feasible. Graft material seems to have an excellent resistance to infection and might be a valuable alternative to traditional replacement materials. Especially long-term durability has to be continuously monitored and documented.

Surgical Atrioventricular Valve Replacement With Melody Valve in Infants and Children.

Background Pediatric patients with atrioventricular valve disease have limited options for prosthetic valve replacement in sizes <15 mm. Based on successful experience with the stented bovine jugular vein graft (Melody valve) in the right ventricular outflow tract, the prosthesis has been modified for surgical valve replacement in pediatric patients with atrioventricular dysfunction with the intention of subsequent valve expansion in the catheterization laboratory as the child grows. Methods and Results A multicenter, retrospective cohort study was performed among patients who underwent atrioventricular valve replacement with Melody valve at 17 participating sites from North America and Europe, including 68 patients with either mitral (n=59) or tricuspid (n=9) replacement at a median age of 8 months (range, 3 days to 13 years). The median size at implantation was 14 mm (range, 9-24 mm). Immediately postoperatively, the valve was competent with low gradients in all patients. Fifteen patients died; 3 patients underwent transplantation. Nineteen patients required reoperation for adverse outcomes, including valve explantation (n=16), left ventricular outflow tract obstruction (n=1), permanent pacemaker implantation (n=1), and paravalvular leak repair (n=1). Twenty-five patients underwent 41 episodes of catheter-based balloon expansion, exhibiting a significant decrease in median gradient ( P<0.001) with no significant increase in grade of regurgitation. Twelve months after implantation, cumulative incidence analysis indicated that 55% of the patients would be expected to be free from death, heart transplantation, structural valve deterioration, or valve replacement. Conclusions The Melody valve is a feasible option for surgical atrioventricular valve replacement in patients with hypoplastic annuli. The prosthesis shows acceptable short-term function and is amenable to catheter-based enlargement as the child grows. However, patients remain at risk for mortality and structural valve deterioration, despite adequate early valvular function. Device design and implantation techniques must be refined to reduce complications and extend durability. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02505074.

Sandwich Osteotomy With Interposition Of A Bovine Block Bone Graft for Vertical Ridge Augmentation

The aim of the present study was to report the clinical case of a patient with a vertical defect of the alveolar ridge, which prevented the installation of dental implants without first treating the defect in question. A 32-year old female patient with a height defect of approximately 6 mm in the region of the missing absent teeth (13 and 14). The patient was treated using the sandwich osteotomy technique, with the interposition of a block bone graft of bovine origin. No complications were reported in the post- operative period. After seven months, two dental implants were installed in the relevant region. The bovine bone graft was incorporated into the relevant area. The bovine bone block graft used in this clinical case was shown to be a viable option for interposition between bone segments that have been osteotomized via sandwich osteotomy.

Electrical stimulation: Complementary therapy to improve the performance of grafts in bone defects?

The limitations of bone reconstruction techniques have stimulated the tissue engineering for the repair of large bone defects using osteoconductive materials and osteoinductive agents. This study evaluated the effects of low intensity electric current on the inorganic bovine graft in calvaria defects. Bone defects were performed with piezoelectric system in the calvaria of Wistar rats divided into four groups (n = 24): (C) without grafting and without electrical stimulation; (E) with grafting; (MC) without grafting and submitted to electrical stimulation; (MC + E) with grafting and submitted to electrical stimulation. Inflammatory, angiogenic and osteogenic events during bone repair at the 10th, 30th, 60th, and 90th days were considered. Several inflammatory markers demonstrated the efficacy of grafting in reducing inflammation, particularly when subjected to electrical stimulation. Angiogenesis and collagen organization were more evident by electrical stimulation application on the grafts. Moreover, the osteogenic cell differentiation process indicated that the application of microcurrent on grafting modulated the homeostasis of bone remodeling. It is concluded that microcurrent favored the performance of grafts in calvarial rat model. Low-intensity electrical current might improve the osteoconductive property of grafting in bone defects. Therefore, electrical current becomes an option as complementary therapy in clinical trials involving bone surgeries and injuries. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 924-932, 2019.

Bioprosthetic pulmonary valve endocarditis: Incidence, risk factors, and clinical outcomes.

Pulmonary valve replacement (PVR) is a common operation in patients with congenital heart disease (CHD). As survival with CHD improves, infective endocarditis (IE) is a growing complication after PVR. The aim of this study was to assess the incidence, risk factors, and clinical outcomes of IE after surgical PVR in patients with CHD at our institution. Retrospective analysis of all cases of surgical PVR performed at Children's Hospital of Wisconsin between 1975 and 2016 was performed. All cases of IE after PVR were identified and clinical and imaging data were obtained by review of medical records. Out of 924 surgical PVRs, there were 19 (2%) cases of IE. The incidence of IE after surgical PVR was 333 cases per 100,000 person-years. The median age at diagnosis of IE was 21 years (range=1.2-34 years) and the median time from PVR to diagnosis of IE was 9.4 years. The overall freedom from IE after PVR was 99.1%, 96.9%, and 93.4%, at 5, 10, and 15 years, respectively. There was no significant difference in freedom from IE based on valve type, including bovine jugular vein grafts. Patients with IE were more likely to have had a history of multiple PVRs, while length of follow-up after PVR, age at time of PVR, and gender were not significant risk factors. Eleven (58%) cases of IE required surgical intervention, while 8 (42%) were successfully treated with intravenous antibiotics alone. There were no deaths and no recurrences of IE after treatment. The overall risk for IE after PVR is low. There was no association between age or type of pulmonary valve and risk of IE. The majority of cases require surgical intervention, but in general the outcomes of IE after PVR are good with low mortality and risk of recurrence.

Fetal bovine dermis as an alternative to allograft in large burn injuries

IntroductionDermal substitutes can be an essential treatment option for patients with very large burn injuries. We reviewed and compared our experience with a fetal bovine dermis dermal substitute versus allograft for adult burn patients with large burn injuries. MethodsAfter obtaining regulatory approval from our local institutional review board, we performed a 1 year retrospective review of adult burn patients with a TBSA of 50% or greater who underwent grafting with either fetal bovine dermis or allograft. We collected data that included age, TBSA, length of stay, number of operations,% area grafted with either allograft or fetal bovine dermis, and time between allograft or fetal bovine dermis grafting to autografting. All mean values are mean ± standard deviation, and all median values are median (interquartile range) ResultsOverall for this review 15 patients met entry criteria. The mean age was 36 ± 9 years and mean TBSA was 71 ± 15%. Mean area grafted with either allograft (ALLO) or fetal bovine dermis (FBD) was 20 ± 8%. Mean time from grafting with ALLO or FB was 30 ± 12 days. There was no difference in median age between the ALLO group (30 (26–31)) and FBD group (35 (32–46) and there was no difference in median TBSA between the ALLO group (68(60–75)%) and FBD group (69(59–88)%). The median area grafted with allograft was 20(20–30)% which was not significantly different than the median area grafted with FBD (16.5(11–26)%). Additionally, there was no difference between the time from grafting with ALLO to autologous skin grafting (26(22–36) days) and the time from grafting with FBD to autologous skin grafting (25.5(21–32) days). ConclusionsFetal bovine dermis is an acceptable alternative to allograft in patients with a large TBSA burn-injury. Further studies are needed to determine if infectious and functional outcomes are improved with fetal bovine dermis.

Histologic and Histomorphometric Analysis of Bone Regeneration with Bovine Grafting Material after 24 Months of Healing. A Case Report.

Anorganic bovine bone mineral matrix (ABBMM) has been reported to have osteoconductive properties and no inflammatory or adverse responses when used as grafting material in sinus augmentation procedures. However, controversy remains in regard to degradation rate of ABBMM. The aim of this study was to histologically and histomorphometrically evaluate the degradation of ABBMM in human bone samples obtained in one patient 24 months after sinus augmentation. Materials and Methods: The histologic and histomorphometric analysis was performed by means of light microscopy in three specimens harvested from the same patient, Results: After 24 months the tissue pattern appeared to be composed of residual particles, some in close contact with the newly formed bone, others separated by translucent areas and osteoid tissues. Newly-formed bone presented different levels of maturation and numerous osteocytes, with greater numbers in bone closer to the grafted particles (27.3% vs. 11.2%, p < 0.05). The histomorphometric analysis showed mean values of 40.84% newly-formed bone, 33.58% residual graft material, 23.84% marrow spaces, and 1.69% osteoid tissue, Conclusions: Even though ABBMM underwent considerable resorption, a great amount of residual grafting material was still present after two years of healing following sinus augmentation. This study confirms that the bovine grafts can be classified as long-term degradation materials.

Extended Pre-Implant Horizontal Ridge Augmentation by Resorbable Membrane and Deproteinized Bovine Bone Mineral Graft: A 5-Year Follow-Up Case Report

Extended Pre-Implant Horizontal Ridge Augmentation by Resorbable Membrane and Deproteinized Bovine Bone Mineral Graft: A 5-Year Follow-Up Case Report

Early cannulation of bovine carotid artery grafts (Artegraft) after primary vascular access and fistula revision procedures

ObjectiveTunneled dialysis catheter (TDC) use has been associated with increased infectious complications and mortality in hemodialysis-dependent patients. Unfortunately, patients who undergo fistula revisions or creation of a new arteriovenous fistula frequently require a TDC during the postoperative period. Bovine carotid artery grafts (BCAGs) can be used as an early-access dialysis conduit to reduce TDC dependence. This study describes the performance of BCAGs that were cannulated early (<3 days) after implantation and associated clinical outcomes. MethodsBCAGs were implanted in 63 consecutive dialysis-dependent patients. Patients and dialysis centers were directly provided early cannulation instructions; 31 (49%) patients were cannulated early, and of the 31 patients cannulated early, 21 (68%) were cannulated during the first postoperative day. Early complications, primary patency, secondary patency, and TDC incidence were monitored through clinic visits, hospital records, and phone calls to dialysis centers. ResultsThe primary patency of BCAGs at 1 year in the early and late cannulation cohorts was 28% and 39%, respectively. The secondary patency of BCAGs at 1 year in the early and late cannulation cohorts was 74% and 77%, respectively. Early complications occurred in 11 (19%) patients who received a BCAG. There were no significant differences in complication rates between early and late cannulation patients. Of the 24 patients who underwent the operation without a pre-existing TDC, only three (13%) required TDC placement during the 30-day postoperative period. ConclusionsBCAGs can be cannulated early without increased complication rates or a negative impact on midterm patency. Early cannulation of BCAGs obviates the need for a TDC postoperatively in dialysis-dependent patients undergoing primary vascular access or fistula revision procedures.

Retraction.

Calvo-Guirado JL, Aguilar-Salvatierra A, Ramírez-Fernández MP, Maté Sánchez de Val JE, Delgado-Ruiz RA, Gómez-Moreno G. Bone response to collagenized xenografts of porcine origin (mp3®) and a bovine bone mineral grafting (4BONE™ XBM) grafts in tibia defects: experimental study in rabbits. Clin Oral Impl Res. 2016;27:1039-1046. The above article, published online on 5 October 2015 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 27, pp. 1039-1046, has been retracted by agreement between the journal Editor in Chief, L Heitz-Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to image discrepancies, resulting in unreliable data. Images in Figures 3d, 4f, 6b, 6c, 6e, and 6f have been used in other publications representing different time points and materials. Reference Calvo-Guirado JL, Aguilar-Salvatierra A, Ramírez-Fernández MP, Maté Sánchez de Val JE, Delgado-Ruiz RA. Gómez-Moreno G. Bone response to collagenized xenografts of porcine origin (mp3® ) and a bovine bone mineral grafting (4BONE™ XBM) grafts in tibia defects: experimental study in rabbits. Clin Oral Impl Res., 2016;27: 1039-1046. https://doi.org/10.1111/clr.12681.

How arteriovenous grafts could help to optimize vascular access management.

A one-size-fits-all approach to vascular access for dialysis may be prejudicial. Arteriovenous fistulae (AVF) have high primary failure, failure to mature rate, and late-stage complications making them unsuitable choice for many patients. Aging of population with chronic kidney disease (CKD) coupled with venous injury during CKD stages depletes suitable superficial veins for AVF creation. The National Institutes of Health consortium demonstrated the difficulty in attaining a functional AVF in hemodialysis patients. Recognition of flaws in AVF and the quest to reduce catheter use bring to the fore the benefits of arteriovenous grafts (AVG). Advances in catheter technologies, flow, care, and antibiotic locks have resulted in significant improvement in catheter-related infections. However, widespread recognition of catheter-related complications like central vein stenosis, metastatic infections, and exhaustion of venous access sites preclude their being a viable alternative to AVF, furthering the need to explore AVG as a substitute. Placement of "early cannulation" AVG is a catheter sparing option in patients who are likely to have inadequate fistula maturation. Advances in biohybrid technology and tissue-engineered grafts are providing a robust opportunity to develop biocompatible graft materials with minimal tissue reactivity and thrombogenicity. Xenografts (bovine carotid artery grafts) are proving to be comparable and, in many cases, better than conventional polytetrafluoroethylene material. Older age, dialysis dependence, and smaller vein size are related to the appropriateness of AVG creation. An individualized approach in selecting optimal upper extremity vascular access option using patient-specific factors while incorporating the benefits of an AVG would greatly aid in achieving low catheter usage in the dialysis population.

PC198. Bovine Carotid Graft as a Conduit in Arterial Trauma

Although endovascular management of traumatic arterial injuries has become more common over the years, open reconstruction remains the mainstay of treatment. Autogenous vein is the preferred conduit for elective bypass, and, when feasible, traumatic injuries. When autogenous conduit is not available, or time does not permit harvest, bovine carotid artery graft (Artegraft, BCAG) is an option. While BCAG has been used for peripheral arterial disease treatment, there is Nothing to disclose on its use in vascular trauma. The purpose of this study was to review the experience with BCAG in vascular trauma at a single level 1 trauma center. The medical records of all patients with traumatic arterial injuries who underwent vascular bypass or interposition with bovine carotid artery from April 2014 to -October 2016 were retrospectively reviewed. Patient records were examined for patency, infection, and limb salvage. BCAG was used in 11 cases of arterial trauma which required open arterial reconstruction. For patients managed with BCAG, 8 were owing to penetrating trauma and 3 to blunt trauma. Patients ranged in age from 22 to 70 years (mean 35.8 years), eight male (73%), and three female (27%). Eighty-two percent involved the lower extremities, 9% involved the upper extremities, and 9% involved the carotid artery. Interventions included two iliofemoral, one femoral to above knee popliteal, two femoral to below knee popliteal or tibial, three SFA interposition grafts, one below the knee popliteal to tibial, one ulnar to radial bypass, and one carotid interposition. Follow-up ranged between 2 and 24 months (mean, 14 months). Based on most recent follow-up data, 64% of grafts had primary patency, while 82% had primary assisted patency. One graft occluded at 4 months in a patient with a posterior knee dislocation with a viable limb after failed attempts at graft salvage. There were no cases of graft or wound infection. There was one early failure, with resultant above knee amputation, on postoperative day 1. There were no deaths. While autologous vein remains the conduit of choice when feasible, traumatic situations do not always permit its use. BCAG is a suitable choice for traumatic arterial injuries when autogenous tissue is not available, either owing to time constraints or absence of suitable conduit. Further research will be needed to determine if BCAG is superior to prosthetic grafts for the trauma patients with arterial injuries.

Three-Dimensional Architecture and Mechanical Properties of Bovine Bone Mixed with Autologous Platelet Liquid, Blood, or Physiological Water: An In Vitro Study.

In recent years, several techniques and material options have been investigated and developed for bone defect repair and regeneration. The progress in studies of composite graft materials and autologous platelet-derived growth factors for bone regeneration in dentistry and their biological and biomechanical properties has improved clinical strategies and results. The aim of this study was to evaluate the three-dimensional architecture and mechanical properties of three different combinations of composite bovine graft, adding autologous platelet liquid (APL), blood, or physiological water. One experimental group for each combination of biomaterials was created. In particular, in Group I, the bovine graft was mixed with APL; in Group II, it was mixed with blood, and in Group III, the biomaterial graft was combined with physiological water. Then, the composite biomaterials were evaluated by scanning electron microscopy (SEM), and a compression-loading test was conducted. The evaluation showed a statistical significance (p < 0.01) of the elastic regime of deformation resistance, in which the combination of APL with bone graft resulted in an 875% increase in the mechanical resistance. The protocol of APL mixed with bovine bone graft produced a composite sticky graft block that was capable of increasing the mechanical properties in order to improve its clinical use in the treatment of the maxillary bone defects.

Autogenous Bone Graft Versus Bovine Bone Graft in Association With Platelet-Rich Plasma for the Reconstruction of Alveolar Clefts: A Pilot Study.

To compare the outcomes of 2 different bone graft materials: autogenous bone grafts from mandibular symphysis and bovine bone grafts associated with platelet-rich plasma (PRP). Twenty individuals met the inclusion criteria and accepted to participate in the study. Group A patients underwent alveolar bone grafting using autologous bone and group B patients using a bovine bone graft associated with PRP. Cone beam computed tomography scans were taken and reconstructed 3-dimensionally for all patients preoperatively and 1 year postoperatively. A significant reduction was detected for area and volume within group A and group B. Between groups, no significant difference was found for area or volume. Bovine grafts associated with PRP are a good option for the reconstruction of alveolar clefts and provide good results such as autologous bone grafts.

Modified technique for Melody valve implantation in the mitral position

Modified technique for Melody valve implantation in the mitral position

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

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. 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. 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. 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 prospective randomized study of bovine carotid artery biologic graft and expanded polytetrafluoroethylene for permanent hemodialysis access

ObjectiveArteriovenous grafts (AVGs) remain reliable substitutes for permanent hemodialysis access in scenarios that preclude the placement of native arteriovenous fistulas (AVFs). The majority of AVGs are constructed of expanded polytetrafluoroethylene (ePTFE), which is relatively inexpensive and readily available, but synthetic AVGs have poor patency rates. On the other hand, biologic grafts confer an advantage by virtue of their inherent similarity to the native human vasculature. However, evidence to support the current preference of synthetic conduits over biologic grafts in clinical practice is scarce. The aim of this protocol is to propose a contemporary re-evaluation and comparison between ePTFE and bovine carotid artery (BCA) grafts. MethodsThis prospective randomized controlled trial is being conducted at an academic hospital center. A total of 100 patients at least 18 years of age and undergoing AVG placement will be recruited and prospectively randomized into two parallel groups with a 1:1 allocation ratio. Patients eligible to receive AVF and those with a known allergic reaction or history of intolerance to any ePTFE or BCA component will not be included in the study. Moreover, patients with a recent active infection at the site of previous AVG placement and patients with a bleeding disorder, an active malignant disease, or a life expectancy <1 year or who refuse blood transfusion and pregnant women will be excluded. Patients will receive either BCA (experimental) or standard ePTFE grafts (control) in compliance with the National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines for AVG creation. Primary end points include primary, primary assisted, secondary, and functional patency at 1 year and 2 years after graft placement. Secondary outcomes include complications (pseudoaneurysms, infections, and steal syndrome) and reintervention rates during the first and second postoperative years. Outcomes will be assessed and documented every 6 months. ResultsOnce the study is completed, analysis of the data will be performed using univariate methods, and Kaplan-Meier and multivariate Cox proportional regression analyses will be employed to evaluate and to compare outcomes between BCA and ePTFE over time. ConclusionsThe creation of a functional and durable dialysis vascular access is crucial in the treatment of patients with end-stage renal disease and is a challenging quest for vascular surgeons. The proposed study compares the outcomes of synthetic and biologic AVG options in patients who are poor candidates for a native AVF. This will help derive contemporary evidence and improve the care of vascular access patients.