ePTFE Grafts Research Articles

Impact of Stent Graft Design on External Iliac Artery Limb Occlusion Rates After Endovascular Aneurysm Repair: Post-hoc Analysis of a Japanese Multicentre Database

It was hypothesised that a helical stent with expanded polytetrafluoroethylene (ePTFE) grafts could provide a preventive effect for external iliac artery (EIA) limb occlusion following endovascular aortic aneurysm repair (EVAR). Therefore, a post-hoc analysis of a Japanese multicentre database was conducted to assess the impact of the stent graft design on EIA limb occlusion rates. Patients who underwent EVAR with EIA limb deployment between 2008 and 2016 were evaluated. The stent graft limbs were divided into two groups: group A comprised stent graft limbs made of a helical stent with ePTFE grafts (Excluder; n=255), and group B comprised stent graft limbs made of a Z stent with polyester grafts (Zenith, Flex and Endurant; n=173). The main outcome was the incidence of limb occlusion and severe limb stenosis (EIA related limb complications). The risk factors for EIA related limb complications were analysed and the midterm results between groups A and B compared. Fine-Gray generalisation of the proportional hazards model was used after propensity score matching to calculate the hazard ratio (HR). One complication occurred in group A and 10 complications occurred in group B. The risk factors for EIA related limb complications for the entire group were a stent graft limb size ≤10mm (HR 5.41; p=.01) and inclusion in group B (HR 14.9; p=.009). After propensity matching, group A (n=159) was matched with group B (n=159). The cumulative incidence function of EIA related limb complications at five years was 0.66% in group A and 7.8% in group B (HR 8.67; p=.039). Stent graft design can affect limb patency in EIA limb deployment. When EIA limb deployment is necessary for patients with a small EIA, such as Japanese patients, stent graft limbs made of a helical stent with ePTFE should be used to reduce the risk of limb occlusion.

Comparison of Acuseal and Standard ePTFE Vascular Grafts for Hemodialysis: A Retrospective Case Series

Background: Grafts, which allow early cannulation have been increasingly used to avoid starting dialysis via tunneled hemodialysis catheters. As we noted graft failures in patients with early cannulation grafts, we reviewed the outcome of these grafts and compared it to ePTFE grafts. Materials and Methods: We retrospectively analyzed time to first intervention, primary and secondary patency rates as well as the number of interventions needed to maintain patency in patients who received an early cannulation graft (GORE® ACUSEAL, acuseal) or an ePTFE (GORE-TEX®) vascular graft between January 2016 and November 2017 in our medical center. Results: 12 patients who had received an acuseal vascular graft were compared with 13 patients with an ePTFE vascular graft. The mean time to first intervention was similar in both groups. On average 0.33 interventions per graft were needed per month to maintain patency in the acuseal group, and 0.08 in the ePTFE group (p = 0.02). The primary patency rate did not differ significantly between the groups. The secondary patency rate at the end of the observation period was significantly worse in the acuseal group (p = 0.02). Four acuseal grafts were lost after a mean of 202 days, whereas none of the ePTFE grafts was lost. Conclusion: Our data is consistent with our clinical impression of an increased number of interventions and lower longevity of the acuseal vascular graft. These data need conformation in a larger cohort.

A Novel Method to Enhance Dynamic Rhinoplasty Outcomes: Double "V" Carving for Alloplastic Grafts.

Augmentation rhinoplasty is one of the most common plastic surgery procedures performed in Asia. Most Asian patients desire not only a natural-looking nose but also a nose with natural feel. Achieving such rhinoplasty outcomes with grafts has been a challenge for surgeons due to rigidity of grafting material. We propose a novel technique to address this limitation. A total of 200 healthy adult patients aged from 18 to 25 years were randomly chosen and classified into 5 groups: A, B, C, D, and control. Each group included 40 patients. The patients assigned to conventional grafting underwent rhinoplasty with L-shaped silicone prosthesis (group A) or expanded polytetrafluoroethylene (e-PTFE; group B), using traditional carving methods. The patients assigned to dynamic rhinoplasty underwent silicone (group C) or e-PTFE grafts (group D) using the modified double "V" method, which involves removing bilateral wedges from the graft to decrease rigidity. Patients in control group do not undergo the surgery. A 3-dimensional raster surface scanner was used to capture the images of the patients accurately and nasal mobility was measured. Subjective evaluations were carried out by a series of questionnaires asked to the patients. The angle α of nasal mobility was significantly lower in conventional grafting (23.09 [5.34] mm for silicone and 17.88 [4.96] mm for e-PTFE) versus the "V" carving (30.53 [3.76] mm for silicone and 23.77 [4.53] mm for e-PTFE; P < .05). The double "V" carving method is a simple, effective, and practical method for improving dynamic nasal outcomes in patient undergoing augmentation rhinoplasty.

Endovascular Repair of an Iliac Artery Pseudoaneurysm Using a Surgeon-Reconstructed Prosthetic Graft and a Bare Metal Stent.

Iliac artery aneurysms are usually asymptomatic. Herein, we report a novel strategy for the repair of a pseudoaneurysm involving the external iliac artery using a conventional artificial graft and bare metal stent. A 76-year-old male patient presented with severe resting pain and right foot discoloration. Computed tomography angiography revealed a right distal external iliac artery pseudoaneurysm, with severe calcified occlusion at the right common and superficial femoral arteries. After exposing the right femoral artery, long-segment endarterectomy and patch angioplasty with the ipsilateral greater saphenous vein were performed. Before the completion of patch angioplasty, a surgeon-modified 8-mm expanded polytetrafluoroethylene (ePTFE) graft was inserted for complete pseudoaneurysm repair. If a commercial covered stent is not available, minimally invasive endovascular repair can be safely performed using a surgeon-modified ePTFE graft and bare metal stent.

Towards compliant small-diameter vascular grafts: Predictive analytical model and experiments

The search for novel, more compliant vascular grafts for the replacement of blood vessels is ongoing, and predictive tools are needed to identify the most promising biomaterials. A simple analytical model was designed that enables the calculation of the ratio between the ultimate stress (σult) and the elastic modulus (E). To reach both the compliance of small-diameter coronary arteries (0.0725%/mmHg) and a burst pressure of 2031 mmHg, a material with a minimum σult/E ratio of 1.78 is required. Based on this result and on data from the literature, random electrospun Polyurethane/Polycaprolactone (PU/PCL) tubular scaffolds were fabricated and compared to commercial ePTFE prostheses. PU/PCL grafts showed mechanical properties close to those of native arteries, with a circumferential elastic modulus of 4.8 MPa and a compliance of 0.036%/mmHg at physiological pressure range (80–120 mmHg) for a 145 μm-thick prosthesis. In contrast, commercial expanded polytetrafluoroethylene (ePTFE) grafts presented a high Young's modulus (17.4 MPa) and poor compliance of 0.0034%/mmHg. The electrospun PU/PCL did not however reach the target values as its σult/E ratio was lower than expected, at 1.54, well below the calculated threshold (1.78). The model tended to overestimate both the compliance and burst pressure, with the differences between the analytical and experimental results ranging between 13 and 34%, depending on the pressure range tested. This can be explained by the anisotropy of random electrospun PU/PCL and its slightly non-linear elastic behavior, in contrast to the hypotheses of our model. Impermeability tests showed that the electrospun scaffolds were impermeable to blood for all thicknesses above 50 μm. In conclusion, this analytical model allows to select materials with suitable mechanical properties for the design of small-diameter vascular grafts. The novel electrospun PU/PCL tubular scaffolds showed strongly improved compliance as compared to commercial ePTFE prostheses.

Domino compensation of the external iliac vein using an ePTFE graft after its procurement for portal vein reconstruction in pancreatic surgery

Domino compensation of the external iliac vein using an ePTFE graft after its procurement for portal vein reconstruction in pancreatic surgery

Domino compensation of the external iliac vein using an ePTFE graft after its procurement for portal vein reconstruction in pancreatic surgery

Domino compensation of the external iliac vein using an ePTFE graft after its procurement for portal vein reconstruction in pancreatic surgery

Improved endothelialization of small-diameter ePTFE vascular grafts through growth factor therapy.

BackgroundProsthetic vascular grafts in humans characteristically lack confluent endothelialization regardless of the duration of implantation. Use of high-porosity grafts has been proposed as a way to induce endothelialization through transgraft capillarization, although early experiments failed to show increased healing in man.ObjectivesWe hypothesized that transduction of tissues around the prosthetic conduit with vectors encoding VEGF receptor-2 (VEGFR2) ligands would augment transinterstitial capillarization and induce luminal endothelialization of high-porosity ePTFE grafts.MethodsFifty-two NZW rabbits received 87 ePTFE uni- or bilateral end-to-end interposition grafts in carotid arteries. Rabbits were randomized to local therapy with adenoviruses encoding AdVEGF-A165, AdVEGF-A109 or control AdLacZ and analyzed at 6 and 28 days after surgery by contrast-enhanced ultrasound and histology.ResultsAdVEGF-A165 and AdVEGF-A109 dramatically increased perfusion in perigraft tissues at 6 days (14.2 ± 3.6 or 16.7 ± 2.6-fold increases, P < 0.05 and P < 0.01). At 28 days, the effect was no longer significantly higher than baseline. At 6 days, no luminal endothelialization was observed in any of the groups. At 28 days, AdVEGF-A109- and AdVEGF-A165-treated animals showed enhanced ingrowth of transinterstitial capillaries (66.0 ± 13.7% and 77.4 ± 15.7% of graft thickness vs 44.7 ± 24.4% in controls, P < 0.05) and improved luminal endothelialization (11.2 ± 26.3% and 11.4 ± 22.2%, AdVEGF-A109 and AdVEGF-A165 vs 0% in controls, P < 0.05). No increased stenosis was observed in the treatment groups as compared to LacZ controls.ConclusionsThis study suggests that transient local overexpression of VEGFR2 ligands in the peri-implant tissues at the time of graft implantation is a novel strategy to increase endothelialization of high-porosity ePTFE vascular grafts and improve the patency of small-diameter vascular prostheses.

Non-Anastomotic Complete ePTFE Axillobifemoral Bypass Disruption and Thrombosis Following Shoulder Dislocation.

Complete disruption of an expanded polytetrafluoroethylene (ePTFE) vascular graft is rare. This is a report of a case of a 70 year old man presenting with left shoulder dislocation, which was reduced immediately. Two weeks later, the patient presented with Rutherford 2b bilateral lower limb ischaemia related to the thrombosis of an ePTFE axillobifemoral bypass. The graft was implanted five years earlier for treatment of an aorto-enteric fistula secondary to an infected aortobifemoral bypass. A non-anastomotic pseudoaneurysm associated with complete disruption of the ePTFE graft was found. Systematic analysis of the explant showed that the rupture occurred at the level of a ringed external support and that ongoing tears also occurred on the posterior wall of the graft at the level of this external support. In conclusion, complete analysis of failure mechanisms even from an isolated report is mandatory.

Amnion-derived mesenchymal stem cells improve viability of endothelial cells exposed to shear stress in ePTFE grafts.

Blood vessel reconstruction is an increasing need of patients suffering from cardiovascular diseases. For the development of microvascular prostheses, efficient endothelialization is mandatory to prevent graft occlusion. Here, we assessed the impact of amnion-derived mesenchymal stem/stromal cells (hAMSC), known for their important angiogenic potential, on the integrity and stability of endothelial cells exposed to shear stress in vascular grafts. Human placental endothelial cells (hPEC) were cultured at the inner surface of an expanded polytetrafluoroethylene (ePTFE) graft positioned within a bioreactor and exposed to a minimal shear stress of 0.015 dyne/cm2 or a physiological shear stress of 0.92 dyne/cm2. hAMSC attached to the outer graft surface were able to interact with human placental endothelial cells by paracrine factors. Microscopical analysis and evaluation of glucose/lactate metabolism evidenced successful cell seeding of the graft: hPEC formed a stable monolayer, hAMSC showed a continuous growth during 72 h incubation. hAMSC improved the viability of hPEC exposed to 0.015 dyne/cm2 as shown by a decreased lactate dehydrogenase release of 13% after 72 h compared to hPEC single culture. The viability-enhancing effect of hAMSC on hPEC was further improved by 13% under physiological shear stress. Angiogenesis array analysis revealed that hPEC exposed to physiological shear stress and hAMSC co-culture reduced the secretion of angiogenin, GRO, MCP-1, and TIMP-2. hAMSC exerted best survival-enhancing effects on hPEC under exposure to physiological shear stress and modulated endothelial function by paracrine factors. Our data support further studies on the development of grafts functionalized with hAMSC-derived secretomes to enable fast clinical application.

Polyester Grafts Are a Risk Factor for Postimplantation Syndrome after Abdominal Endovascular Aneurysm Repair: Retrospective Analysis for Polyester Graft, Excluder®, and Endologix Powerlink®/AFX®.

Objective: Postimplantation syndrome (PIS) is a postoperative syndrome that occurs after endovascular aneurysm repair (EVAR), accompanied by high fever, leukocytosis, and high serum C-reactive protein (CRP). Its pathogenesis and clinical meaning are still under discussion. Here, we evaluate the relationship between postoperative fever after EVAR and graft fabric focusing on Endologix Powerlink® and AFX® (EPL/AFX).Materials and Methods: From January 2015 to July 2017, data on elective EVAR for abdominal aortic aneurysm (AAA) using mainbody were retrospectively collected. The primary endpoint was maximal postoperative fever.Results: We identified 128 patients who underwent elective EVAR for AAA (105 males, 82%; aged 57–90, median: 74 years). The median maximal postoperative fever was 37.8°C (36.6–39.7°C): polyester graft, 38.2°C (37.1–39.7°C); Excluder®, 37.8°C (36.6–39.2°C); and EPL/AFX, 37.7°C (37–38.7°C). The maximal postoperative fever with a polyester graft was significantly higher than that with an expanded polytetrafluoroethylene (ePTFE) graft (p<0.001). However, there was no difference between Excluder® and EPL/AFX (p=0.214).Conclusion: In this study, it was found that polyester grafts are significantly associated with PIS after elective EVAR for AAA. If patient anatomy is permitted, it may be better to choose the ePTFE graft, especially for patients with a poor general condition.

Improved endothelialization of small-diameter ePTFE grafts through growth factor therapy.

Background: Prosthetic vascular grafts in humans characteristically lack confluent endothelialization regardless the duration of implantation. Use of high-porosity grafts has been proposed as a way to induce endothelialization through transgraft capillarization, although early experiments failed to show increased healing in man. Objectives: We hypothesized that transduction of tissues around the prosthetic conduit with vectors encoding VEGF Receptor-2 (VEGFR2) ligands would augment transinterstitial capillarization and induce luminal endothelialization of high-porosity PTFE grafts. Methods: Fifty-two NZW rabbits received 87 ePTFE uni- or bilateral end-to-end interposition grafts in carotid arteries. Rabbits were randomized to local therapy with adenoviruses encoding AdVEGF-A165, AdVEGF-A109 or control AdLacZ and analyzed at 6 and 28d after surgery by contrast-enhanced ultrasound and histology. Results: AdVEGF-A165 and AdVEGF-A109 dramatically increased perfusion in perigraft tissues at 6d (14.2±3.6 or 16.7±2.6- fold increases, P&lt;0.05 and P&lt;0.01). At 28d the effect was no longer significantly higher than baseline. At 6d no luminal endothelialization was observed in any of the groups. At 28d, AdVEGF-A109 and AdVEGF-A165 treated animals showed enhanced ingrowth of transinterstitial capillaries (66.0±13.7% and 77.4±15.7% of graft thickness vs. 44.7±24.4% in controls, P&lt;0.05) and improved luminal endothelialization (11.2±26.3% and 11.4±22.2%, AdVEGF-A109 and AdVEGF-A165 vs. 0% in controls, P&lt;0.05). No increased stenosis was observed in the treatment groups as compared to LacZ controls. Conclusions: This study suggests that transient local overexpression of VEGFR2 ligands in the peri-implant tissues at time of graft implantation is a novel strategy to increase endothelialization of high-porosity ePTFE vascular grafts and improve the patency of small-diameter vascular prostheses.

Experimental comparative study of thrombogenicity of two differently luminal heparinized ePTFE vascular prosthetics.

Introduction; Heparin bonded grafts have proven to improve patency, at least transiently.Two different heparin bonded expanded polytetrafluoroethylene (ePTFE) grafts produced by different technologies are currently available.This pilot primary goal was to test these commonly used, but differently heparinized ePTFE grafts for differences in primary patency after a 6-months follow-up in a sheep model. Secondly, the aim was to establish a large animal model to enable future translational studies and further graft development.Method; End-to-side bypass of the common carotid artery was performed bilaterally in sheep. Either a Gore® Propaten heparinized graft or a Jotec® Flowline Bipore heparinized graft was used, both 5 mm in diameter.Following graft implantation, the sheep were kept on pasture for 6 months, with monthly duplex scans to determine patency. At termination, the grafts were duplex scanned a final time, with the animals sedated, and the grafts were removed for heparin activity analysis.Results; 14 sheep were operated, 11 survived total follow-up time. At final follow-up, 4 patent Gore® grafts, and 6 Jotec® remained. Mean patency time was 106.7 ± 21.9(SD) days and 96.2 ± 25.9(SD) days for Gore® and Jotec®, respectively. Log-rank test showed no significant difference at final follow-up after 6 months. Post mortem heparin analysis showed no significant difference in mean activity.Conclusion; Based on patency data alone, no significant difference between these grafts were found. In accordance, heparin activity analysis showed no difference between the grafts. The model itself, proved easily implementable, and provides many possibilities for future studies, though some adjustments should be made to improve survival.

In Situ Graft Replacement for a Ruptured Abdominal Aortic Aneurysm Infected with Listeria monocytogenes after Endovascular Aneurysm Repair.

Listeria monocytogenes infection and rupture of the aneurysm sac, after endovascular aneurysm repair (EVAR), are both rare. We report the case of an 82-year-old man who presented with a ruptured aneurysm by infection with L. monocytogenes after EVAR. We successfully treated him by in situ reconstruction with a bifurcated expanded polytetrafluoroethylene (ePTFE) graft, with partial removal of the infected stent graft. At 30 months from the reoperation, the patient was in good health at home, with no symptoms of infection, and the gallium-67-citrate single-photon emission computed tomography/computed tomography (SPECT/CT) fusion images confirmed no fluid accumulation.

Clinical outcomes of patients with adjacent-organ injuries by expanded polytetrafluoroethylene grafts used for middle hepatic vein reconstruction in living donor liver transplantation: a single-center experience

Introduction: Congestion of the right liver (RL) anterior section without middle hepatic vein (MHV) may lead to graft dysfunction. Various outflow reconstruction methods have been devised to prevent congestion. An expanded polytetrafluoroethylene (ePTFE) graft may be used for anterior section drainage. We recently experienced several cases of injuries of adjacent organs caused by ePTFE grafts. The aim of this study was to explore these rare complications and their clinical outcomes in a single center. Methods: From January 2005 to December 2016, 638 patients underwent RL living donor liver transplantation draining MVH branches with ePTFE grafts. Medical records of recipients who developed ePTFE-related adjacent-organ injuries were retrospectively reviewed. Results: ePTFE-related adjacent-organ injuries developed in 5 patients (0.78%). The mean interval between transplantation and identification of injury was 73.4±38.1 months. All patients presented with dyspepsia. ePTFE graft induced injury of the gastric antrum or duodenal bulb was observed in 3 patients, one at the small bowel with fistula formation, and another at the common bile duct (CBD). Such injuries were identified by gastroscopy and computed tomography (CT). The patient with gastric antrum perforation did not receive aggressive treatment although the remaining graft penetrated the gastric wall but no leakage. In one patient with duodenal bulb injury, ePTFE graft was removed with gastroscopy. In the remaining 3 patients, surgical exploration and ePTFE graft removal was performed. Conclusion: Although the incidence of adjacent-organ injuries by ePTFE graft is rare, close monitoring of ePTFE grafts is necessary since unexpected injuries can occur during long-term follow-up.

Combined liver and inferior vena cava resection with reconstruction using artificial vascular graft for liver tumors

Introduction: In cases with liver tumors accompanied with inferior IVC invasion, IVC resection is sometimes required as a chance for cure with liver resection. Furthermore, IVC reconstruction with artificial vascular graft is also needed after the resection when area of defect after the IVC resection is large. There have been few reports of cases with IVC reconstruction using the graft. Methods: The study included 12 cases undergoing liver resection with IVC resection and subsequent reconstruction using artificial vascular graft. Surgical outcome of the cases were investigated. Results: The resected liver tumor was intrahepatic cholangiocarcinoma in four cases, metastatic liver tumor from colorectal cancer in three, liver sarcoma in two, adrenal cancer in one, malignant lymphoma in one, and inflammatory pseudotumor in one. IVC resection and reconstruction was performed under IVC clamp with remnant liver perfusion in six cases, and under THVE in six cases. ePTFE graft was used for IVC patch in one case and for replacement of the entire circumference of IVC in 11 cases Median operative time was 650 min. (range; 360 to 1050 min.) and blood loss was 2600 mL (range; 1196 to 8030 mL). Postoperative complication developed in two patients; bleeding in one and bile leakage in the other one. There were no operative mortality cases. During postoperative follow-up period, no complications associated with the graft were observed and the grafts remained patent in all the cases. Conclusion: These results suggested favorable outcome of liver resection with IVC resection and reconstruction using artificial vascular graft.

Proximalization of Arterial Inflow for Treatment of Hemodialysis-Induced Arterial Steal Syndrome

This was a retrospective analysis of proximalization of arterial inflow for treatment of hemodialysis access-related arterial steal syndrome. We performed 12 proximalization procedures during a span of 18 months. The proximalization procedure was performed by creating a bypass from the axillary artery to the arteriovenous (AV) fistula and disconnecting the AV fistula from the brachial artery inflow source. Retrospective review of data was performed to evaluate indications, outcomes, complications, and technical pitfalls. Retrospective review was conducted of patients who underwent proximalization of arterial inflow from July 2016 to March 2018. We performed this procedure on 12 patients. Indications for the procedure were intractable pain in the hand at all times in seven patients, tissue loss in three patients, and severe pain during dialysis treatment in two patients. All patients were diagnosed with arterial steal syndrome with Doppler ultrasound studies, and subsequent angiography was performed to confirm the diagnosis and to rule out inflow correctable lesions. Selection of patients for proximalization was based on relatively small size of the brachial artery in comparison to the AV fistula and low flow volumes. We used expanded polytetrafluoroethylene (ePTFE) grafts in all patients. Three patients received four to seven tapered grafts, and the remaining patients received 5-mm or 6-mm ePTFE grafts. Two patients had graft thrombosis within 30 days postoperatively. These appeared to be due to hypotension during dialysis. On further investigation, one of these had venous outflow stenosis, which was corrected by angioplasty of the venous outflow. This patient also required stenting of the anastomosis between the ePTFE graft and the fistula because of stenosis. The other patient had graft revision with a larger conduit. There was no mortality in 30 days. All patients showed improvement in perfusion of the affected hand. One patient had no significant improvement in numbness and was referred for neurologic evaluation. Two patients had partial resolution of pain. The remaining patients had resolution of pain, and all patients with tissue loss healed their ulcers. Proximalization of arterial inflow can help resolve hemodialysis access-related arterial steal syndrome in the majority of patients in whom the brachial artery is small.

Design and Fabrication of a Biomimetic Vascular Scaffold Promoting in Situ Endothelialization and Tunica Media Regeneration.

Multilayered vascular scaffolds may be considered advantageous in regenerating vascular tissues due to the nature of mimicking the native structure of a blood vessel. However, there are currently limited small-diameter vascular scaffolds integrating the specific features of native tunica intima (anti-thrombus and rapid endothelialization) and tunica media (the alignment and ingrowth of smooth muscle cells (SMCs), structural elements capable of promoting vascular regeneration and function). To address this limitation, we developed a modified electrospinning method capable of fabricating a bilayer vascular scaffold with a 2-mm inner diameter and investigated the in vivo performance and regenerative capacity using a rat abdominal aorta, with a 2-month implantation period. The vascular scaffold was fabricated from poly(l-lactide-co-caprolactone)/collagen (PLCL/COL) nanofibers and nanofiber yarns, comprising the luminal and medial layers, respectively. Heparin and anti-CD133 antibody (HEP/CD133) were incorporated into the PLCL/COL nanofibers comprising the luminal layer. The mechanical characterizationdemonstrated compliance of the bilayer scaffold, which was comparable to the human saphenous vein and improved over commercially available e-PTFE grafts. The incorporated components (HEP/CD133) were released over a period of nearly 40 days, during which the nanofibers and nanofiber yarns maintained their structure. Moreover, the released heparin contributed to lumen anticoagulation functionality initially, and the incorporated anti-CD133 antibody promoted the development of a neo-intima. In addition, SMCs proliferated and penetrated throughout the entire nanofiber yarn outer structure. In vivo evaluations demonstrated that a monolayer of endothelial cells (CD31 positive), as well as the aligned and infiltrated smooth muscle tissues (α-SMA positive), were regenerated on the inner and outer layers of the fabricated scaffold, respectively, demonstrating the capacity to regenerate structures mimicking native blood vessels. In conclusion, the functionalized bilayer scaffold can be viewed as a promising candidate for in situ vascular tissue regeneration.

Concomitant presentation and surgical management of an abdominal aortic aneurysm and translocation XP11.2 associated renal cell carcinoma in a female infant

Abstract Abdominal Aortic Aneurysms are rare in the infant population, when these occur are secondary to connective tissue diseases, vasculitis, and infectious etiology or in relation with tuberous sclerosis. We herein present an 11 month-girl who was diagnosed with a translocation Xp11.2 associated left renal cell carcinoma (RCC). In addition to this finding, a Computed Tomography Angiography (CTA) revealed a 2.8 centimeters (cm) dilatation of the infrarenal aorta consistent with a fusiform aneurysm. She underwent concomitant left nephrectomy and aneurysm repair with a 14 millimeters (mm) expanded polytetrafluoroethylene (ePTFE) graft. Following the procedure the patient recovered without complications and she was discharged five days later. To our knowledge this is the first concomitant presentation of an abdominal aortic aneurysm and a translocation Xp11.2 RCC in an infant patient treated successfully by tumor resection and aortic reconstruction. At one year of follow up she is developing according to her age without complications.

Resection of the inferior vena cava in patients with renal cell carcinoma with bulky tumor venous thrombosis

Objective: to develop an effective and safe surgical technique for the treatment of patients with renal cell carcinoma with invasive tumor venous thrombosis of the inferior vena cava (IVC).Materials and methods. The study included 75 patients underwent surgical treatment at the N.N. Blokhin Russian Cancer Research Center between 1995 and 2017. The median age of patients was 57 years (range: 32–72 years). All patients were diagnosed with RCC with invasive tumor venous thrombosis levels II–IV; of them, 55 patients (73.3 %) had complete IVC obstruction and mature venous collaterals. Twenty- seven patients (26.0 %) were diagnosed with regional, 37 (49.3 %) – with distant metastases. Prior nephrectomy was performed in 5 (6.7 %) cases. Surgical treatment included nephrectomy (n = 70; 93.3 %), thrombectomy with IVC resection (n = 75; 100 %), and metastasectomy in solitary distant lesions (n = 11; 14.7 %). Partial IVC resection was demanded in 18 patients (24.0 %): with infrarenal IVC plication – 14 (18.7 %), with reconstruction of IVC with synthetic patch – 4 (5.3 %). Fifty-seven patients (76.0 %) underwent circular IVC resection (with left renal vein (LRV) ligation – 35 (46.7 %)). The IVC was replaced with ePTFE grafts in 4 (5.3 %) patients, IVC reconstruction was not required in 53 (70.7 %) patients. IVC grafting was considered to be justified in patients without mature venous collaterals. Twenty-two patients (29.3 %) received systemic antitumor therapy. Median follow-up was 32.3 months (range: 1–226 months).Results. Median operative time was 237.5 min (range: 135–580 min); median blood loss – 7000 mL (range: 1200–27 000 mL). The post- operative complications rate was 52.1 % (grades III–V – 31.5 %). Hospital mortality was 13.3 % (10 of 75 patients). Thirty-two months overall, cancer-specific, and recurrence-free survival were 42.4 %, 49.5 %, and 61.2 % respectively. At 19 months all prosthesis were patent. None of the patients had glomerular filtration rate &lt;60 ml/min/1.73 m2 after LRV ligation. No patients developed disabling chronic venous insufficiency of the lower limbs after IVC ligation/resection without grafting.Conclusion. Nephrectomy, thrombectomy, and IVC resection is the only effective method of treatment for RCC with invasive tumor venous thrombosis. The development of IVC and LRV venous collaterals allows performing circular IVC resection with LRV ligation without graft replacement.