The safety of bovine tissue arterial repair in removal of infected prosthetic hemodialysis grafts.

BACKGROUND: More than 400,000 Americans require dialysis, and many receive it via a prosthetic arteriovenous graft. Infection of these grafts is rare, but associated with significant morbidity and mortality. The gold standard is total graft excision with arteriotomy closure. This was previously done with autologous vein, but bovine tissue offers a reasonable alternative. The objective of this article is to evaluate a community hospital experience with bovine tissue arterial repair after total graft excision of infected prosthetic arteriovenous graft. METHODS: A retrospective review was performed of all cases of infected prosthetic arteriovenous graft removal with bovine tissue arterial repair was performed. Thirteen cases were identified. Presentation, location of graft, and causative organism were reviewed; outcomes including reoperation and mortality were recorded. RESULTS: Of the 13 patients, 12 (92%) had positive cultures of the graft, bloodstream, or wound. Methicillin-resistant Staphylococcus aureus was the most commonly isolated organism (54%). There were two unplanned reoperations including hematoma drainage and wound debridement within the first year. Over the 1-year follow-up period, 1 patient died for a mortality of 8%. There were no re-infections during follow-up. DISCUSSION: Prosthetic arteriovenous graft infection remains a difficult challenge and is associated with significant morbidity and mortality. It presents in a variety of ways, including within an old thrombosed graft. Over the last several years, the causative organism has increasingly become drug resistant. Treatment with total graft excision requires arteriotomy closure, and for this bovine tissue has been demonstrated to be a viable option.

Comparison between bovine carotid artery graft and polytetrafluoroethylene graft for haemodialysis vascular access: A systematic review and meta-analysis.

BACKGROUND: There is a renewed interest in using bovine carotid artery grafts for haemodialysis vascular access after recent advances in conduit manufacturing and endovascular management of access-related complications. Our aim was to summarize the results of the recent studies comparing bovine carotid artery grafts with polytetrafluoroethylene grafts as vascular access for haemodialysis. METHODS: A systematic review was conducted for original articles comparing bovine carotid artery with polytetrafluoroethylene grafts for haemodialysis vascular access published between January 2000 and December 2019 searching the databases of Medline, Scopus, Google Scholar, ClinicalTrials.gov and the Cochrane Central Register of Controlled Trials. RESULTS: Four studies were included (one prospective randomized controlled trial and three retrospective studies) with 676 patients in total (bovine carotid artery: 395, polytetrafluoroethylene: 281). There was lower graft infection rate per patient-year in bovine carotid artery grafts (mean difference: -0.03, p < 0.0001). Bovine carotid artery grafts required fewer interventions per patient-year to maintain or restore patency (mean difference: -0.81, p = 0.002). No significant difference was detected regarding pseudoaneurysm formation (p = 0.24), steal syndrome (p = 0.11) or patency rates (primary: 1 year: p = 0.15, 2 years: p = 0.69; primary assisted: 1 year: p = 0.18, 2 years: p = 0.54; secondary: 1 year: p = 0.22, 2 years: p = 0.17). CONCLUSION: Bovine carotid artery and polytetrafluoroethylene grafts have similar short-term and long-term outcomes, with a possible advantage of bovine carotid artery grafts concerning graft infections and number of required interventions. Thus, bovine carotid artery grafts can be a useful alternative modality for haemodialysis vascular access.

Airway reconstruction using decellularized aortic xenografts in a dog model.

Tracheal reconstruction after extensive resection remains a challenge in thoracic surgery. Aortic allograft has been proposed to be a potential tracheal substitute. However, clinically, its application is limited for the shortage of autologous aortic segment. Whether xenogeneic aortic biosheets can be used as tracheal substitutes remains unknown. In the present study, we investigated the possibility in dog model. The results show that all dogs were survived without airway symptoms at 6 months after tracheal reconstruction with gently decellularized bovine carotid arteries. In the interior of engrafted areas, grafted patch integrated tightly with the residual native tracheal tissues and tracheal defects in the lumen were repaired smoothly without obvious inflammation, granulation, anastomotic leakage, or stenosis. In addition, histological and scanning electron microscopy examination showed that grafted patches were covered with ciliated columnar epithelium similar to epithelium in native trachea, which indicated successfully re-epithelialization of decellularized bovine carotid arteries in dogs. These findings provide preclinical investigation of xenogeneic aortic biosheets in serving as tracheal substitute in a dog model, which proposes that decellularized biosheets of bovine carotid may be a potential material for bioartificial tracheal graft.

Adventitial Collagen Crosslink Reduces Intimal Hyperplasia in a Rabbit Arteriovenous Graft Model.

BACKGROUND: Intimal hyperplasia (IH) is the initial lesion of vein graft failure after coronary artery bypass grafting. The weak venous wall is likely one of the primary reasons for IH after exposure to the arterial environment. We investigate whether adventitial collagen cross-link by glutaraldehyde (GA) reinforces the venous wall and then reduces IH. MATERIALS AND METHODS: Adventitial collagen cross-link by 0.3% GA was performed on the rabbit jugular veins. The degree of cross-link was accessed by tensile test. The jugular vein with or without cross-link was implanted into the carotid artery of rabbit. Vein dilatation at the immediate anastomosis and pathological remodeling of vein graft after 4 wk was assessed. RESULTS: Tensile test indicated that the mechanical property of 3-min cross-linked veins more closely resembled that of the carotid artery. In rabbit arteriovenous graft models, 3-min adventitial collagen cross-link limited overdistension (diameter: 3.24 mm versus 4.65 mm, P < 0.01) at the immediate anastomosis and reduced IH (intima thickness: 78.83 µm versus 140.19 µm, P < 0.01) of vein grafts 4 wk after implantation in the cross-link group as compared with the graft group (without cross-link). Compared with the cross-link group, the expression of proliferating cell nuclear antigen and vascular cell adhesion molecule-1 increased significantly at both the mRNA and protein levels within the graft group (P < 0.01), but the expression of smooth muscle-22α decreased significantly (P < 0.01). CONCLUSIONS: Adventitial collagen cross-link by GA increased the vessel stiffness and remarkably reduced IH in a rabbit arteriovenous graft model.

Decellularized equine carotid artery layers as matrix for regenerated neurites of spiral ganglion neurons.

Today's best solution in compensating for sensorineural hearing loss is the cochlear implant, which electrically stimulates the spiral ganglion neurons in the inner ear. An optimum hearing impression is not ensured due to, among other reasons, a remaining anatomical gap between the spiral ganglion neurons and the implant electrodes. The gap could be bridged via pharmacologically triggered neurite growth toward the electrodes if biomaterials for neurite guidance could be provided. For this, we investigated the suitability of decellularized tissue. We compared three different layers (tunica adventitia, tunica media, and tunica intima) of decellularized equine carotid arteries in a preliminary approach. Rat spiral ganglia explants were cultured on decellularized equine carotid artery layers and neurite sprouting was assessed quantitatively. Generally, neurite outgrowth was possible and it was most prominent on the intima (in average 83 neurites per spiral ganglia explants, followed by the adventitia (62 neurites) and the lowest growth on the media (20 neurites). Thus, decellularized equine carotid arteries showed promising effects on neurite regeneration and can be developed further as efficient biomaterials for neural implants in hearing research.

Comparison of Autologous Vein and Bovine Carotid Artery Graft as a Bypass Conduit in Arterial Trauma.

BACKGROUND: Surgical revascularization is the mainstay treatment in treating most traumatic arterial injuries, and autologous great saphenous vein is widely regarded as the conduit of choice. However, the use of the great saphenous vein may be limited by many factors, and there are little data to guide management in this setting. Bovine carotid artery graft (Artegraft, Inc., North Brunswick, NJ, USA) is a biologic conduit that has been used in select trauma cases at our center. The objective of this study was to review and compare our experience with autologous vein and bovine carotid artery in traumatic arterial injuries requiring bypass or interposition. METHODS: This is a retrospective review of all patients with a traumatic arterial injury repaired with autologous vein or bovine carotid artery graft at a single center between April 2014 and October 2016. Outcomes of interest included differences in duration of ischemia, operative times, patency, limb salvage, graft-related complications, and functional status. RESULTS: Thirty patients were included in this study. Seventeen (57%) injuries were to the lower extremity (LE) and 13 (43%) to the upper extremity. Bovine carotid artery graft was used as a conduit in 12 (40%) cases, while autologous vein was used in 18 (60%) patients. Patients were predominantly male (90%). Mean age was 31 ± 15 years. Comorbidities did not differ significantly between the groups. Mean follow-up duration was 19 ± 13 months. Overall primary patency was 82%: bovine versus autologous vein (78% vs. 85%; P = 0.68). Overall secondary patency was 91%: bovine versus autologous vein (78% vs. 100%; P = 0.16). Overall limb salvage was 90%: bovine versus autologous vein (82% vs. 94%; P = 0.28). When comparing bovine carotid artery graft to autologous vein in LE interventions, primary patency (50% vs. 71%; P = 0.40), secondary patency (75% vs. 100%; P = 0.23), and limb salvage (80% vs. 86%; P = 0.76) did not differ significantly. There were no early or late graft infections with either conduit. There were no significant differences in ambulatory status at discharge by graft type. Overall survival was 100%. CONCLUSIONS: In this series, there is a trend toward improved patency and limb salvage with autologous vein. Autologous vein should be the standard of care for revascularization of traumatic arterial injuries. Bovine carotid artery graft appears be a viable alternative, especially in patients requiring urgent revascularization, that does not significantly compromise patency, limb salvage, or functional outcomes.

Outcomes of venous bypass combined with thoracic outlet decompression for treatment of upper extremity central venous occlusion.

BACKGROUND: Upper extremity central venous stenosis results from a variety of environmental and anatomic conditions, including venous thoracic outlet syndrome, the presence of device leads or catheters, and the turbulence created by the presence of arteriovenous fistulas or grafts. In cases of total occlusion, especially at the bony costoclavicular junction, options for endovascular treatment and open venous reconstruction are limited and bypass grafting may be needed. We describe our experience with venous bypass combined with thoracic outlet decompression in a cohort of symptomatic patients with subclavian vein occlusion. METHODS: A prospectively collected database of patients was queried for patients treated for central venous obstructive disease with venous bypass in the setting of both symptomatic venous thoracic outlet syndrome and ipsilateral arteriovenous access from July 2012 to December 2017. All but one patient presented with arm swelling and had either failed to respond to or were unsuitable for endovenous therapy. One patient desired elective removal of a venous stent because of pain and anxiety. Operative procedures were performed at the discretion of the operating surgeon. RESULTS: Fourteen patients (eight men; average age, 42 years) underwent open thoracic outlet decompression with first rib resection (n = 11) or claviculectomy (n = 4). Indication for treatment was dialysis-associated venous outlet obstruction in five, effort thrombosis (Paget-Schroetter syndrome) in seven, presence of a venous implantable cardioverter-defibrillator lead in one, and patent but painful venous stent in situ with significant anxiety. Nine patients required first interspace sternotomy for exposure of the proximal subclavian vein. One patient with acute Paget-Schroetter syndrome had been treated with preoperative thrombolysis without resolution; all others were chronically occluded. Bypass conduit was jugular vein in one, bovine carotid artery graft in two, paneled great saphenous vein in two, femoral vein in eight, and polytetrafluoroethylene in one. Mean operative time was 187 (±45) minutes, with mean estimated blood loss of 379 (±209) mL. There were two early graft thromboses that were revised with jugular venous turndown and femoral vein bypass, respectively. All patients experienced immediate symptom relief. Morbidity included two graft thromboses, two instances of wound dehiscence, two operative site hematomas, non-ST elevation myocardial infarction, vein harvest site infection, polytetrafluoroethylene graft infection, and phrenic nerve injury. At a mean follow-up of 357 (±303) days, primary assisted patency and secondary patency for the entire cohort were 71.4% and 85.7%, respectively, with 100% primary assisted patency among those with femoral vein conduit. At last follow-up, 13 of the 14 living patients (93%) remained symptom free. CONCLUSIONS: In our experience, venous bypass combined with thoracic outlet decompression achieves symptomatic relief in approximately 90% of patients with symptomatic upper extremity central venous occlusion, with morbidity limited to the perioperative period.

Expression of a Functional IL-2 Receptor in Vascular Smooth Muscle Cells.

Many nonlymphoid cell types express at least two, if not all three, subunits of the IL-2R; although, compared with lymphocytes, relatively little is known about how IL-2 affects the function of nonlymphoid cells. The limited information available suggests that IL-2 has a substantial impact on cells such as gastrointestinal epithelial cells, endothelial cells, and fibroblasts. In a previous report from our laboratory, we noted that IL-2 and IL-2Rß-deficient mice lose smooth muscle cells over time, eventually resulting in aneurysmal aortas and ectatic esophagi. This finding, combined with our work showing that IL-2 surrounds vascular smooth muscle cells by association with perlecan, led us to ask whether vascular smooth muscle cells express an IL-2R. Toward this end, we reported the expression of IL-2Rß on human and murine vascular smooth muscle cells. We now report that vascular smooth muscle cells express all three subunits of the IL-2R, and that expression of IL-2Rα varies with vascular smooth muscle cell phenotype. Furthermore, we show that, through a functional IL-2R, IL-2 initiates signaling pathways and impacts vascular smooth muscle cell function. Finally, we demonstrate that IL-2 expression increases upon initiation of conditions that promote intimal hyperplasia, suggesting a mechanism by which the IL-2/IL-2R system may impact this widespread vascular pathology.

Rapamycin Combined with α-Cyanoacrylate Contributes to Inhibiting Intimal Hyperplasia in Rat Models / Rapamicina em Combinação com α-Cianoacrilato Contribui à Inibição de Hiperplasia Intimal em Modelos em Ratos

Abstract Background: Vein graft restenosis has an adverse impact on bridge vessel circulation and patient prognosis after coronary artery bypass grafting. Objectives: We used the extravascular supporter α-cyanoacrylate (α-CA), the local application rapamycin/sirolimus (RPM), and a combination of the two (α-CA-RPM) in rat models of autogenous vein graft to stimulate vein graft change. The aim of our study was to observe the effect of α-CA, RPM, and α-CA-RPM on vein hyperplasia. Methods: Fifty healthy Sprague Dawley (SD) rats were randomized into the following 5 groups: sham, control, α-CA, RPM, and α-CA-RPM. Operating procedure as subsequently described was used to build models of grafted rat jugular vein on carotid artery on one side. The level of endothelin-1 (ET-1) was determined by enzyme-linked immunosorbent assay (ELISA). Grafted veins were observed via naked eye 4 weeks later; fresh veins were observed via microscope and image-processing software in hematoxylin-eosin (HE) staining and immunohistochemistry after having been fixed and stored" (i.e. First they were fixed and stored, and second they were observed); α-Smooth Muscle Actin (αSMA) and von Willebrand factor (vWF) were measured with reverse transcription-polymerase chain reaction (RT-PCR). Comparisons were made with single-factor analysis of variance and Fisher's least significant difference test, with p < 0.05 considered significant. Results: We found that intimal thickness of the α-CA, RPM, and α-CA-RPM groups was lower than that of the control group (p < 0.01), and the thickness of the α-CA-RPM group was notably lower than that of the α-CA and RPM groups (p < 0.05). Conclusion: RPM combined with α-CA contributes to inhibiting intimal hyperplasia in rat models and is more effective for vascular patency than individual use of either α-CA or RPM.

Resumo Fundamento: Reestenose de enxertos venosos tem um impacto adverso na circulação de pontagens e no prognóstico de pacientes após a cirurgia de revascularização miocárdica. Objetivos: Nós utilizamos α-cianoacrilato (α-CA) como suporte extravascular, rapamicina/sirolimus (RPM) como aplicação local e a combinação dos dois (α-CA-RPM) em modelos de enxerto venoso autógeno em ratos para estimular mudança no enxerto venoso. O objetivo do nosso estudo foi observar o efeito de α-CA, RPM e α-CA-RPM na hiperplasia venosa. Métodos: Cinquenta ratos Sprague Dawley (SD) saudáveis foram randomizados nos 5 grupos seguintes: sham, controle, α-CA, RPM e α-CA-RPM. O procedimento operacional descrito subsequentemente foi utilizado para construir modelos de enxertos da veia jugular na artéria carótida em ratos, em um lado. O nível de endotelina-1 (ET-1) foi determinado por ensaio de imunoabsorção enzimática (ELISA). As veias enxertadas foram observadas a olho nu 4 semanas após; as veias frescas foram observadas via microscópio e software de processamento de imagem com coloração hematoxilina-eosina (HE) e imuno-histoquímica depois de serem fixadas e armazenadas; α-actina do músculo liso (αSMA) e o fator de von Willebrand (vWF) foram medidos com reação em cadeia da polimerase-transcriptase reversa (RT-PCR). Realizaram-se as comparações com análise de variância de fator único (ANOVA) e o teste de diferença mínima significativa (LSD) de Fisher, com p < 0,05 sendo considerado estatisticamente significante. Resultados: Nós achamos que a espessura intimal nos grupos α-CA, RPM e α-CA-RPM era menor que no grupo controle (p < 0,01) e a espessura no grupo α-CA-RPM era notavelmente menor que nos grupos α-CA e RPM (p < 0,05). Conclusão: A combinação de RPM e α-CA contribui à inibição de hiperplasia em modelos em ratos e é mais efetivo para patência vascular que uso individual de α-CA ou RPM.

Supra-aortic vessel reconstruction in total arch replacement for acute type A dissection: Comparison of en bloc and separate graft techniques.

OBJECTIVE: To compare the outcomes of the en bloc and branched graft techniques for supra-aortic vessel reconstruction in total arch replacement (TAR) for acute type A aortic dissection (ATAAD). METHODS: In 53 ATAAD patients with intact supra-aortic arch vessels undergoing TAR, the arch vessels were reconstructed using the branched graft technique in 35 patients and en bloc technique in 18, i.e. reimplantation of the innominate artery and the left carotid artery (LCA) and transposition of left subclavian artery to LCA. The early and mid-term outcomes were compared between two groups. RESULTS: The selective antegrade cerebral perfusion time in en bloc group was significantly longer (33 ± 10 vs 24 ± 7 min, p = 0.001). Operative mortality was 5.7% (3/53), including 1 and 2 in the en bloc and branched graft groups, respectively (5.6% vs 5.7%, p = 0.981). Stroke occurred in 1 patient. No spinal cord injury occurred. At mean 4.3 ± 1.6 years, clinical and CT follow-up were complete in 100% and 86% (43/50). No cerebrovascular accidents or upper extremity claudication occurred. There were 4 deaths and 1 reintervention in follow-up. Survival was 88.6% and 88.9% at 3 months, and 83.3% and 88.6% at 6 months, 3 and 5 years in the en bloc and branched graft groups, respectively (p = 0.597). The arch vessels were patent in 100% (43/43) without stenosis or aneurysm. CONCLUSIONS: The modified en bloc technique could achieve comparable early and mid-term outcomes to the branched graft technique in patients undergoing TAR for ATAAD. This approach may be an alternative technique for ATAAD patients with intact supra-aortic arch vessels.

Early Cannulation of Bovine Carotid Artery Graft Reduces Tunneled Dialysis Catheter-Related Complications: A Comparison of Bovine Carotid Artery Graft Versus Expanded Polytetrafluoroethylene Grafts in Hemodialysis Access.

INTRODUCTION:: In patients who receive chronic hemodialysis but do not have autogenous venous conduit for a native dialysis access, nonautologous grafts serve as an alternative conduit of choice. This study compared the clinical outcome of hemodialysis access using bovine carotid artery graft (BCAG) and prosthetic polytetrafluoroethylene (PTFE) graft in patients who receive chronic hemodialysis. METHODS:: An analysis of all patients undergoing hemodialysis using either BCAG or PTFE grafts from 2010 to 2017 was performed. Clinical outcomes were analyzed including graft patency as well as associated complications related to dialysis grafts and tunneled dialysis catheter (TDC). RESULTS:: During the study period, 142 patients received BCAG and 128 patients received PTFE graft implantation for dialysis access. The mean duration from graft implantation to graft cannulation in the BCAG and PTFE group was 12.3 ± 8.5 days versus 43.5 ± 16.4, respectively ( P = .01). Bovine carotid artery graft group had a higher 2-year primary patency rate (33% vs 14%, P = .03) and assisted primary rate (57% vs 23%, P = .02) compared to the PTFE group. The 2-year secondary patency rates were similar between the 2 groups (56% vs 53%, P = .69). Complication rates in the BCAG and PTFE group was 1.69 ± 0.24 per patient-year versus 2.54 ± 0.48 per patient-year, respectively ( P = .01). Tunneled dialysis catheter-related infection was greater in the PTFE group compared to the BCAG group (10.87 ± 2.61 vs 5.69 ± 0.98 per 1000 TDC days; P = .02). Bovine carotid artery graft cohorts group required a mean of 1.69 interventions per patient-year, compared to 2.76 per patient-year for the PTFE group ( P = .03). CONCLUSIONS:: Bovine carotid artery graft permits earlier cannulation for hemodialysis access with superior primary and assisted primary patency rates compared to PTFE grafts. Patients with BCAG experienced shorter indwelling TDC duration and less TDC-related complications compared to PTFE cohorts.

Rapamycin Combined with α-Cyanoacrylate Contributes to Inhibiting Intimal Hyperplasia in Rat Models.

BACKGROUND: Vein graft restenosis has an adverse impact on bridge vessel circulation and patient prognosis after coronary artery bypass grafting. OBJECTIVES: We used the extravascular supporter α-cyanoacrylate (α-CA), the local application rapamycin/sirolimus (RPM), and a combination of the two (α-CA-RPM) in rat models of autogenous vein graft to stimulate vein graft change. The aim of our study was to observe the effect of α-CA, RPM, and α-CA-RPM on vein hyperplasia. METHODS: Fifty healthy Sprague Dawley (SD) rats were randomized into the following 5 groups: sham, control, α-CA, RPM, and α-CA-RPM. Operating procedure as subsequently described was used to build models of grafted rat jugular vein on carotid artery on one side. The level of endothelin-1 (ET-1) was determined by enzyme-linked immunosorbent assay (ELISA). Grafted veins were observed via naked eye 4 weeks later; fresh veins were observed via microscope and image-processing software in hematoxylin-eosin (HE) staining and immunohistochemistry after having been fixed and stored" (i.e. First they were fixed and stored, and second they were observed); α-Smooth Muscle Actin (αSMA) and von Willebrand factor (vWF) were measured with reverse transcription-polymerase chain reaction (RT-PCR). Comparisons were made with single-factor analysis of variance and Fisher's least significant difference test, with p < 0.05 considered significant. RESULTS: We found that intimal thickness of the α-CA, RPM, and α-CA-RPM groups was lower than that of the control group (p < 0.01), and the thickness of the α-CA-RPM group was notably lower than that of the α-CA and RPM groups (p < 0.05). CONCLUSION: RPM combined with α-CA contributes to inhibiting intimal hyperplasia in rat models and is more effective for vascular patency than individual use of either α-CA or RPM.

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

OBJECTIVE: Tunneled 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. METHODS: BCAGs 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. RESULTS: The 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. CONCLUSIONS: BCAGs 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.

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

OBJECTIVE: Arteriovenous 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. METHODS: This 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. RESULTS: Once 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. CONCLUSIONS: The 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.

Decellularized and Secured Porcine Arteries with NaOH-based Process: Proof of Concept.

BACKGROUND: There is a need for small caliber vascular prosthesis. Synthetic grafts are hindered by thrombogenicity and rapid occlusion. Decellularized matrices could be an alternative. We assessed in vitro and in vivo the biocompatibility of porcine artery treated with a chemical/physical process for decellularization and graft securitization with non/conventional pathogens inactivation. METHODS: Porcine carotid arteries (PCA) were treated. First, biopsies (n = 4/tissue) were performed before/after treatment to assess decellularization (hematoxylin and eosin/-4',6-diamidino-2-phenylindole/DNA/Miller). Second, 5 rats received an abdominal aortic patch of decellularized PCA (DPCA). Four pigs received subcutaneous DPCA implants (n = 2/pig). Half were explanted at day 15 and half at day 30. Finally, 2 pigs received DPCA (n = 2) and polytetrafluoroethylene prosthesis (n = 1), respectively, as carotid interposition. Implants were removed at day 30. Inflammation (CD3 and CD68 immunostaining) calcifications (von Kossa staining), remodeling (hematoxylin and eosin), and vascular characterization (CD31 and alpha-smooth muscle actin immunofluorescent staining) were investigated. RESULTS: Ninety-five percentage of decellularization was obtained without structural deterioration. No death occurred. Low inflammatory reaction was found in the 2 models for DPCA. Acquisition of vascular identity was confirmed in the rodent and porcine models. Similarity between native PCA and DPCA was observed after 30 days. In contrast, polytetrafluoroethylene graft showed severe calcifications, higher CD3 reaction, and higher intimal hyperplasia (P < 0.05). CONCLUSIONS: The physical and chemical process ensures decellularization of carotid porcine arteries and their in vivo remodeling with the presence of an endothelium and smooth-muscle-like cells as well as a low level of inflammatory cells.

The use of vascular homografts in pediatric small bowel transplantation: Single-center experience over a decade.

Intestinal transplantation in children has evolved with more isolated small intestine transplants being performed compared to combined liver-intestine transplants. Consequently, surgical techniques have changed, frequently requiring the use of vascular homografts of small caliber to revascularize the isolated small intestine, the impact of which on outcomes is unknown. Among 106 pediatric intestine and multivisceral transplants performed at our center since 2003, 33 recipients of an isolated small intestine graft were included in this study. Outcome parameters were thrombotic complications, graft, and patient survival. A total of 29 of 33 (87.9%) patients required arterial and/or venous homografts from the same donor, mainly iliac or carotid artery and iliac or innominate vein, respectively (donor's median age 1.1 years [2 months to 23 years], median weight 10 kg [14.7-48.5]). Post-transplant, there were three acute arterial homograft thromboses and one venous thrombosis resulting in two peri-operative graft salvages and two graft losses. Three of four thromboses occurred in patients with primary hypercoagulable state, including the two graft losses. Overall, at a median of 4.1 years (1-10.2) from transplant, 29 of 33 (88%) patients are alive with 26 of 33 (79%) functioning grafts. The procurement of intact, size-matched donor vessels and the management of effective post-transplant anticoagulation are critical.

Lower Extremity Bypass Using Bovine Carotid Artery Graft (Artegraft): An Analysis of 124 Cases with Long-Term Results.

INTRODUCTION: Although biological grafts have been utilized as a vascular conduit in leg bypass for many years, reports of a bovine carotid artery graft (BCAG) in lower extremity revascularization have been scarce. This study analyzed the outcome of lower leg bypass using BCAG. METHODS: A retrospective review of a prospectively collected database of all patients undergoing lower extremity bypass using BCAG from 2002 to 2017 was performed. Clinical outcomes including graft patency and limb salvage were evaluated. RESULTS: A total of 124 BCAG (Artegraft, North Brunswick, NJ) were implanted in 120 patients for lower extremity revascularization. Surgical indications included disabling claudication in 12%, rest pain in 36%, tissue loss in 48%, and infected prosthetic graft replacement in 3%. Autologous saphenous vein was either inadequate or absent in 72% of patients. BCAG was used in 46 patients (37%) who had a prior failed ipsilateral leg bypass. Distal anastomosis was performed in the above-knee popliteal artery, below-knee popliteal artery, and tibial artery in 30 cases (25%), 32 cases (26%), and 48 cases (39%), respectively. Distal anastomotic patch was created in all tibial artery to allow BCAG-tibial reconstruction. The yearly primary patency rates in 5 years were 86.5, 76.4, 72.2, 68.3, and 67.5%, respectively. The corresponding yearly secondary patency rates were 88.5, 84.7, 82.4, 78.5, and 75.6%, respectively. The limb salvage rate at one year was 83.6% and at five years was 86.2% for patients with critical limb ischemia. Multivariate analysis showed poor runoff score (P = 0.03, 95% CI, 1.3-5.3; OR, 1.6) was independently associated with graft occlusion. CONCLUSION: BCAG is an excellent vascular conduit and provides good long-term results in lower extremity bypass.

Left axillary to right atrium anterior chest wall graft using bovine carotid artery conduit.

INTRODUCTION: Central venous occlusive (CVO) disease involving the superior vena cava (SVC) and inferior vena cava (IVC) can occur frequently in patients with end-stage renal disease (ESRD) on chronic dialysis. Dialysis access is essential for the survival of these patients. CASE DESCRIPTION: We report a case of a chest wall graft creation using bovine carotid artery conduit in a patient who was experiencing life-threatening loss of dialysis access secondary to her SVC and IVC occlusion along with a hypercoagulable state. We did a subcutaneous anterior chest wall graft from the left axillary artery to the right atrium (RA) using a mini thoracotomy incision. CONCLUSIONS: ESRD patients with CVO pose a unique challenge. We believe our approach can provide an excellent option for dialysis access in patients with exhausted conventional access options.

Use of bovine carotid artery for buttonhole technique hemodialysis.

PURPOSE: Assess the feasibility of using a bovine carotid artery graft for buttonhole technique hemodialysis in patients who are not candidates for a native fistula. METHODS: Case reports used to demonstrate selection criteria and results for this approach. Criteria include: knowledgeable patient with prior dialysis experience, stable graft in place for 3 months minimum, not a candidate for a native fistula, and able to maintain close follow-up. RESULTS: Both grafts were based on axillary vessels and have been in place for a total of 64 months. They have been used for dialysis via buttonhole for a total of 40 months. There have been three procedures on these patients, post-buttonhole use (.87/year). There have been no infections. CONCLUSIONS: These patients were carefully selected based on desire, support, knowledge/experience and ability. Their success suggests that buttonhole technique for hemodialysis on a synthetic semi-biologic graft can be accomplished with morbidity and longevity similar to any graft using non-buttonhole needle access.

Triton X-100 combines with chymotrypsin: A more promising protocol to prepare decellularized porcine carotid arteries.

BACKGROUND: Morbidity and mortality of cardiovascular diseases are increasing in recent years. To solve these problems, vascular transplantation has become a common approach. Decellularization has been a hot spot of tissue engineering to prepare vessel substitutes for vascular transplantation. However, there is no established canonical protocol for decellularization thus far. OBJECTIVE: To further understand the decellularization effect of decellularization protocols and the causal relationship between decellularization and mechanical properties. METHODS: Three decellularization protocols including two chemical protocols based on SDS and Trypsin respectively and a combination of Triton X-100 with chymotrypsin were adopted to obtain decellularized porcine carotid arteries in our study. After decellularization, histological analysis, scanning electron microscopy and mechanical tests were performed to evaluate their efficiency on removing of cellular components, retention of extracellular matrix and influence on mechanical properties. RESULTS: All these decellularization protocols used in our study were efficient to remove cellular components. However, SDS and trypsin performed more disruptive effect on ECM structure and mechanical properties of native arteries while Triton X-100 combines with chymotrypsin had no significant disruptive effect. CONCLUSIONS: Compared with decellularization protocols based on SDS and trypsin, Triton X-100 combines with chymotrypsin used in our study may be a more promising protocol to prepare decellularized porcine carotid arteries for vascular tissue engineering applications.