Predictors of amputation-free survival and wound healing after infrainguinal bypass with alternative conduits.

OBJECTIVE: Inadequate vein quality or prior harvest precludes use of autologous single segment greater saphenous vein (ssGSV) in many patients with chronic limb-threatening ischemia (CLTI). Predictors of patient outcome after infrainguinal bypass with alternative (non-ssGSV) conduits are not well-understood. We explored whether limb presentation, bypass target, and conduit type were associated with amputation-free survival (AFS) after infrainguinal bypass using alternative conduits. METHODS: A single-center retrospective study (2013-2020) was conducted of 139 infrainguinal bypasses performed for CLTI with cryopreserved ssGSV (cryovein) (n = 71), polytetrafluoroethylene (PTFE) (n = 23), or arm/spliced vein grafts (n = 45). Characteristics, Wound, Ischemia, and foot Infection (WIfI) stage, and outcomes were recorded. Multivariable Cox proportional hazards and classification and regression tree analysis modeled predictors of AFS. RESULTS: Within 139 cases, the mean age was 71 years, 59% of patients were male, and 51% of cases were nonelective. More patients undergoing bypass with cryovein were WIfI stage 4 (41%) compared with PTFE (13%) or arm/spliced vein (27%) (P = .04). Across groups, AFS at 2 years was 78% for spliced/arm, 79% for PTFE, and 53% for cryovein (adjusted hazard ratio for cryovein, 2.5; P = .02). Among cases using cryovein, classification and regression tree analysis showed that WIfI stage 3 or 4, age >70 years, and prior failed bypass were predictive of the lowest AFS at 2 years of 36% vs AFS of 58% to 76% among subgroups with less than two of these factors. Although secondary patency at 2 years was worse in the cryovein group (26% vs 68% and 89% in arm/spliced and PTFE groups; P < .01), in patients with tissue loss there was no statistically significant difference in wound healing in the cryovein group (72%) compared with other bypass types (72% vs 87%, respectively; P = .12). CONCLUSIONS: In patients with CLTI lacking suitable ssGSV, bypass with autogenous arm/spliced vein or PTFE has superior AFS compared with cryovein, although data were limited for PTFE conduits for distal targets. Despite poor patency with cryovein, wound healing is achieved in a majority of cases, although it should be used with caution in older patients with high WIfI stage and prior failed bypass, given the low rates of AFS.

Longer Operative Time for Lower Extremity Bypass Surgery is Associated With Inferior Outcomes.

INTRODUCTION: This study aims to assess the association of operative time with the postoperative length of stay and unplanned return to the operating room in patients undergoing femoral to below knee popliteal bypasses, stratified by autologous vein graft or polytetrafluoroethylene (PTFE). MATERIALS AND METHODS: A retrospective analysis of vascular quality initiative database (2003-2021). The selected patients were grouped into the following: vein bypass (group I) and PTFE (group II) patients. Each group was further stratified by a median split of operative time (i.e., 210 min for autologous vein and 155 min for PTFE) to study the outcomes. The outcomes were assessed by univariate and multivariate approach. RESULTS: Of the 10,902 patients studied, 3570 (32.7%) were in the autologous vein group, while 7332 (67.3%) were in the PTFE group. Univariate analysis revealed autologous vein and PTFE graft recipients that had increased operative times were associated with a longer mean postoperative length of stay and a higher incidence of all-cause return to the operating room. In PTFE group, patients with prolonged operative times were also found to be associated with higher incidence of major amputation, surgical site infection, and cardiovascular events, along with loss of primary patency within a year. CONCLUSIONS: For patients undergoing femoral to below knee popliteal bypasses using an autologous vein or PTFE, longer operative times were associated with inferior outcomes. Mortality was not found to be associated with prolonged operative time.

Regenerative and durable small-diameter graft as an arterial conduit.

Despite significant research efforts, clinical practice for arterial bypass surgery has been stagnant, and engineered grafts continue to face postimplantation challenges. Here, we describe the development and application of a durable small-diameter vascular graft with tailored regenerative capacity. We fabricated small-diameter vascular grafts by electrospinning fibrin tubes and poly(ε-caprolactone) fibrous sheaths, which improved suture retention strength and enabled long-term survival. Using surface topography in a hollow fibrin microfiber tube, we enable immediate, controlled perfusion and formation of a confluent endothelium within 3-4 days in vitro with human endothelial colony-forming cells, but a stable endothelium is noticeable at 4 weeks in vivo. Implantation of acellular or endothelialized fibrin grafts with an external ultrathin poly(ε-caprolactone) sheath as an interposition graft in the abdominal aorta of a severe combined immunodeficient Beige mouse model supports normal blood flow and vessel patency for 24 weeks. Mechanical properties of the implanted grafts closely approximate the native abdominal aorta properties after just 1 week in vivo. Fibrin mediated cellular remodeling, stable tunica intima and media formation, and abundant matrix deposition with organized collagen layers and wavy elastin lamellae. Endothelialized grafts evidenced controlled healthy remodeling with delayed and reduced macrophage infiltration alongside neo vasa vasorum-like structure formation, reduced calcification, and accelerated tunica media formation. Our studies establish a small-diameter graft that is fabricated in less than 1 week, mediates neotissue formation and incorporation into the native tissue, and matches the native vessel size and mechanical properties, overcoming main challenges in arterial bypass surgery.

Broad variation in prosthetic conduit use for femoral-popliteal bypass is not justified on the basis of contemporary outcomes favoring autologous great saphenous vein.

BACKGROUND: Single-segment great saphenous vein (GSV) has been the preferred conduit for femoral-popliteal (FP) bypass, particularly for a popliteal artery target below the knee. Yet, controversy persists surrounding whether prosthetic conduit can yield comparable outcomes to GSV for FP bypass to either the above-knee (AK) or below-knee (BK) popliteal artery. We sought to analyze national variation in conduit use and to compare contemporary outcomes in FP bypass. METHODS: A retrospective review of elective FP bypass in the Vascular Quality Initiative database using single-segment GSV or polytetrafluoroethylene (PTFE) from 2003 to 2018 was performed. Variation in conduit use was examined on a regional and center level. Characteristics of the patients and operative factors were compared. Effects of conduit on 1-year outcomes were assessed using Kaplan-Meier and multivariable Cox regression analyses. RESULTS: Of 7430 FP bypasses performed in the Vascular Quality Initiative, 3930 (53%) used GSV and 3500 (47%) used PTFE. Conduit use differed for AK-popliteal bypass (38% GSV and 62% PTFE) and BK-popliteal bypass (67% GSV and 33% PTFE). PTFE use was inversely correlated with preoperative vein mapping among centers (ρ = -0.55; P < .001). This inverse correlation was stronger for AK-popliteal bypasses (ρ = -0.61; P < .0001) than for BK-popliteal bypasses (ρ = -0.34; P = .0004). Overall, patients undergoing FP bypass with PTFE were more likely to be older and to have multiple medical comorbidities. Operative outcomes were similar between groups, although FP bypass with GSV incurred higher rates of wound infection (P < .001) and reoperation for bleeding, thrombosis, or revision (P < .01). At 1-year follow-up, GSV patients had higher graft occlusion-free survival (83% vs 78%; P < .001) and amputation-free survival (87% vs 82%; P < .001). These differences were observed for both AK-popliteal and BK-popliteal artery subgroups. On multivariable analyses stratified by bypass target, PTFE use was independently associated with increased risk of graft occlusion (AK-popliteal: hazard ratio [HR], 1.4 [P = .002]; BK-popliteal: HR, 1.3 [P = .02]) and amputation (AK-popliteal: HR, 1.4 [P = .006]; BK-popliteal: HR, 1.6 [P < .001]) at both target levels. CONCLUSIONS: PTFE is frequently used in FP bypass, representing two-thirds of AK-popliteal FP bypasses and one-third of BK-popliteal FP bypasses. However, PTFE use varies widely among centers. GSV was associated with higher rates of wound infection and reoperation and PTFE was associated with inferior 1-year outcomes independent of target artery level. GSV should be used for FP bypass whenever it is clinically feasible. Decreasing variation in prosthetic conduit use may be a useful quality improvement metric.

Autologous Vascularization: A Method to Enhance the Antibacterial Adhesion Properties of ePTFE.

BACKGROUND: Expanded polytetrafluoroethylene (ePTFE), an ideal bioimplant material, is commonly used in surgical repair to treat soft tissue defects and deformities. However, the main disadvantage of ePTFE is that its distinctive porous ultrastructure is prone to bacterial adhesion that gives rise to infection and chronic inflammation, resulting in functional failure. Herein, a potentially promising approach to ePTFE autologous vascularization (AV-ePTFE) in vivo was established and developed to enhance the material's antibacterial properties. METHODS: Hematoxylin and eosin (H&E) staining and visual observation were performed to validate the intensity of the inflammatory response and related histological changes in surgical wounds after AV-ePTFE implantation. In addition, the antibacterial activities of AV-ePTFE were assessed by an in vitro bacterial adhesion assay and scanning electron microscope observation. RESULTS: The optimal time point of AV-ePTFE was 12 weeks after implantation. AV-ePTFE relieved inflammation based on an inflammation grading evaluation and expedited wound healing. Furthermore, AV-ePTFE effectively reduced the number of bacterial adhesions, inhibited bacterial biofilm formation, and prevented the occurrence of infection. CONCLUSIONS: We conclude that autologous vascularization is an effective method to improve the antibacterial adhesion properties and biocompatibility of ePTFE after implantation and that it may have a significant effect on clinical application of future porous biomaterials.

Comparison of Clinical Outcomes between Endovascular Therapy with Self-Expandable Nitinol Stent and Femoral-Popliteal Bypass for Trans-Atlantic Inter-Society Consensus II C and D Femoropopliteal Lesions.

BACKGROUND: Femoral-popliteal (F-P) bypass is the standard treatment for lower extremity peripheral artery disease with severe femoropopliteal (FP) artery lesions. However, in clinical settings, these patients are treated with endovascular therapy (EVT) because of frailty and difficulties with general anesthesia. We compared the clinical outcomes of F-P bypass and EVT for severe FP artery lesions and investigated the types of patients for whom EVT would be as appropriate as F-P bypass. METHODS: This multicenter, retrospective study included 452 Trans-Atlantic Inter-Society Consensus (TASC) II C and D FP artery lesions in 352 patients. A total of 350 lesions in 260 patients (74 ± 9 years, 66% male, 60% claudication) were treated with EVT with nitinol self-expandable stents, and 102 lesions in 92 patients (71 ± 9 years, 75% male, 40% claudication) were treated with F-P bypass. The primary outcome measure was primary patency, and the influence of baseline characteristics on its association with the treatment strategy (EVT versus F-P bypass) was assessed using a Cox proportional hazards regression model. RESULTS: Kaplan-Meier analysis indicated that the 3-year primary patency rate was significantly lower for EVT than F-P bypass (60% vs. 74%, P < 0.01). The body mass index (BMI) and C-reactive protein (CRP) levels significantly interacted with the treatment strategy for restenosis (P < 0.05). The adjusted hazard ratios of EVT versus F-P bypass for restenosis were 0.77 (P = 0.46) in cases with a low BMI (≤18 kg/m2) or an elevated CRP level (≥1 mg/dL) and 3.35 (P < 0.01) in other cases. The 3-year primary patency rate was not significantly different between the EVT and F-P bypass groups in patients with BMI ≤ 18 kg/m2 or CRP ≥ 1 mg/dL (57% vs. 45%, P = 0.84). CONCLUSIONS: In TASC II C and D lesions, EVT appears to yield patency comparable to that of F-P bypass in patients with a low BMI or an elevated CRP level, but lower patency in other patients.

Paclitaxel-coated balloon in the treatment of recurrent dysfunctional arteriovenous access, real-world experience and longitudinal follow up.

AIM: Dysfunctional arteriovenous (AV) access remains a significant cause of morbidity and hospital admission for patients with end stage renal failure on haemodialysis. This study was performed to evaluate the impact of paclitaxel-coated Balloon (PCB) on the patency of AV access with recurrent stenoses. METHODS: We retrospectively studied haemodialysis patients who presented to our centre with recurrent AV access dysfunction and compared intervention-free patency using plain balloon versus PCB. RESULTS: A total of 147 patients were followed up longitudinally. Intervention-free patency was better following PCB compared to previous intervention using plain balloons (6.4 ± 5.8 versus 4.0 ± 3.7, P < 0.01). The 3- and 6-month patency rates after PCB were significantly better compared to standard plain angioplasty balloon: 69.4% versus 52.4%, P < 0.01 and 42.9% versus 15.6%, P < 0.01 respectively. Kaplan-Meier survival analysis of circuit patency demonstrated the superiority of PCB over plain balloon angioplasty in both arteriovenous fistula and arteriovenous graft (P < 0.01 and P = 0.01 respectively) although the patency of arteriovenous fistula remained significantly better than arteriovenous graft following interventions with PCB (P < 0.01). Age of AV access and the number of previous interventions were found to be significant predictors of patency following PCB intervention. CONCLUSION: Arteriovenous access intervention with PCB was shown to be superior compared to plain balloon in the treatment of both non-thrombosed and thrombosed AV accesses in our multi-ethnic population.

Vascular Remodeling Process of Heparin-Conjugated Poly(ε-Caprolactone) Scaffold in a Rat Abdominal Aorta Replacement Model.

In the field of vascular graft research, poly-ε-caprolactone (PCL) is used owing to its good mechanical strength and biocompatibility. In this study, PCL scaffold was prepared by electrospinning and surface modification with heparin via hexamethylenediamine. Then the scaffolds were implanted into the infrarenal abdominal aorta of Wistar rats and contrast-enhanced micro-ultrasound was used to monitor the patency of grafts after implantation. These grafts were extracted from the rats at 1, 3, and 6 months for histological analysis, immunofluorescence staining, and scanning electron microscopy observation. Although some grafts experienced aneurysmal change, results showed that all implanted grafts were patent during the course of 6 months and these grafts demonstrated well-organized neotissue with endothelium formation, smooth muscle regeneration, and extracellular matrix formation. Such findings confirm feasibility to create heparin-conjugated scaffolds of next-generation vascular grafts.

External polytetrafluoroethylene reinforcement of varicose autologous vein grafts in peripheral bypass surgery produces durable bypass function.

OBJECTIVE: Use of autologous veins as peripheral bypass graft may become critical in the presence of significant varicose degeneration of the harvested vein. External support of such dilated veins with standard polytetrafluoroethylene (PTFE) prostheses was recommended as an option to use these veins for peripheral bypass. A single-center experience with this technique regarding long-term graft function, secondary reinterventions, and potential graft degeneration is presented. METHODS: Between January 1995 and January 2006, there were 54 patients with varicose veins who underwent 57 consecutive infrainguinal vein bypass operations with PTFE reinforcement in 57 limbs. Indications for surgery consisted of disabling claudication (5), chronic critical ischemia (40), popliteal aneurysm (11), and acute ischemia (1). Grafts were observed with duplex ultrasound scan supplemented by additional angiography in case of recurrent ischemia, with prospective documentation of follow-up data in a computerized vascular database. Graft patency, limb salvage, and possible degeneration of the vein grafts were retrospectively analyzed. RESULTS: Mean follow-up was 79 months (range, 1-219 months). The 30-day mortality was 2%. Secondary procedures to maintain or to restore bypass patency were necessary in 12 grafts (21%). Primary, primary assisted, and secondary patency rates were 54%, 73%, and 73% after 5 years for all bypasses, with a limb salvage rate for limbs operated on for chronic critical or acute ischemia of 83%. Significant stenosis of a reinforced vein segment was detected in one case after 56 months, with subsequent replacement of the vein graft with a biologic vascular prosthesis. CONCLUSIONS: Good late graft patency and limb salvage combined with a low rate of late vein graft degeneration justify the use of external PTFE reinforcement of varicose vein segments in infrainguinal bypass surgery.

The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm.

BACKGROUND: Decision-making related to the care of patients with an abdominal aortic aneurysm (AAA) is complex. Aneurysms present with varying risks of rupture, and patient-specific factors influence anticipated life expectancy, operative risk, and need to intervene. Careful attention to the choice of operative strategy along with optimal treatment of medical comorbidities is critical to achieving excellent outcomes. Moreover, appropriate postoperative surveillance is necessary to minimize subsequent aneurysm-related death or morbidity. METHODS: The committee made specific practice recommendations using the Grading of Recommendations Assessment, Development, and Evaluation system. Three systematic reviews were conducted to support this guideline. Two focused on evaluating the best modalities and optimal frequency for surveillance after endovascular aneurysm repair (EVAR). A third focused on identifying the best available evidence on the diagnosis and management of AAA. Specific areas of focus included (1) general approach to the patient, (2) treatment of the patient with an AAA, (3) anesthetic considerations and perioperative management, (4) postoperative and long-term management, and (5) cost and economic considerations. RESULTS: Along with providing guidance regarding the management of patients throughout the continuum of care, we have revised a number of prior recommendations and addressed a number of new areas of significance. New guidelines are provided for the surveillance of patients with an AAA, including recommended surveillance imaging at 12-month intervals for patients with an AAA of 4.0 to 4.9 cm in diameter. We recommend endovascular repair as the preferred method of treatment for ruptured aneurysms. Incorporating knowledge gained through the Vascular Quality Initiative and other regional quality collaboratives, we suggest that the Vascular Quality Initiative mortality risk score be used for mutual decision-making with patients considering aneurysm repair. We also suggest that elective EVAR be limited to hospitals with a documented mortality and conversion rate to open surgical repair of 2% or less and that perform at least 10 EVAR cases each year. We also suggest that elective open aneurysm repair be limited to hospitals with a documented mortality of 5% or less and that perform at least 10 open aortic operations of any type each year. To encourage the development of effective systems of care that would lead to improved outcomes for those patients undergoing emergent repair, we suggest a door-to-intervention time of <90 minutes, based on a framework of 30-30-30 minutes, for the management of the patient with a ruptured aneurysm. We recommend treatment of type I and III endoleaks as well as of type II endoleaks with aneurysm expansion but recommend continued surveillance of type II endoleaks not associated with aneurysm expansion. Whereas antibiotic prophylaxis is recommended for patients with an aortic prosthesis before any dental procedure involving the manipulation of the gingival or periapical region of teeth or perforation of the oral mucosa, antibiotic prophylaxis is not recommended before respiratory tract procedures, gastrointestinal or genitourinary procedures, and dermatologic or musculoskeletal procedures unless the potential for infection exists or the patient is immunocompromised. Increased utilization of color duplex ultrasound is suggested for postoperative surveillance after EVAR in the absence of endoleak or aneurysm expansion. CONCLUSIONS: Important new recommendations are provided for the care of patients with an AAA, including suggestions to improve mutual decision-making between the treating physician and the patients and their families as well as a number of new strategies to enhance perioperative outcomes for patients undergoing elective and emergent repair. Areas of uncertainty are highlighted that would benefit from further investigation in addition to existing limitations in diagnostic tests, pharmacologic agents, intraoperative tools, and devices.

A retrospective comparative study of venous vs nonringed expanded polytetrafluoroethylene extension grafts for anterior sector outflow reconstruction in right lobe living donor liver transplantation.

BACKGROUND: Prosthetic vessel grafts are increasingly being used for anterior sector (AS) outflow reconstruction in right lobe living donor liver transplantation (RL-LDLT) in view of easy availability and proper fit. The aim of the study was to analyze technique and outcomes of AS reconstruction using nonringed expanded polytetrafluoroethylene (ePTFE) grafts and compare outcomes with venous extension grafts. METHODS: This is a retrospective study of 437 consecutive RL-LDLTs from January 2014 to August 2015. Vein (V) and ePTFE (alone or composite) were used alternatively or best fit for particular right lobe graft. RESULT: V graft was used in 200 recipients and ePTFE in 237 recipients with comparable preoperative donor and recipient characteristics. Cold ischemia time was significantly high in the ePTFE group. Postoperative recipient outcomes were comparable between the groups. The graft patency rate was comparable between the groups at different time intervals of follow-up. However, 12-month patency was low in those with multiple venous tributaries than with single outflow reconstruction ([V 90%, ePTFE 86.7%] vs [V 97.4%, ePTFE 95.2%]). No patient was re-explored for graft blockage. There was no significant difference in 30-day (V 92%, ePTFE 94.5%, P = 0.34), 90-day (V 90%, ePTFE 90.7%, P = 0.87) and one-year (V 87.5%, ePTFE 89%, P = 0.66) patient survival between the groups. CONCLUSION: Expanded polytetrafluoroethylene gives equivalent patency and recipient outcomes with the added advantage of proper size match fit, allowing more complex AS reconstruction with ease without increased infection rate or associated complications.

Wall thickness control in biotubes prepared using type-C mold.

A type-C mold based on in-body tissue architecture was previously developed for preparing small-diameter biotube vascular grafts with a 2-mm diameter and approximately 1-mm wall thickness. In this study, the type-C mold was modified for preparing large-diameter biotubes with controlled wall thicknesses. Four types of molds were assembled by inserting silicone center rods (outer diameters 11, 13, 15, 17 mm) into stainless steel cages (inner diameter 19 mm) and surgically embedded in the abdominal subcutaneous pouches of Holstein cows. After 8-12 weeks, connective tissues occupied the rod-cage gap in the molds to form biotubes. The wall thickness of the biotubes obtained after removing the molds was approximately 1-3 mm, which corresponded to approximately 80% of each gap distance. The breaking strength almost linearly increased with the wall thickness of the biotubes. The strength of the biotubes with wall thickness over 1.5 mm was higher than that of beagle blood vessels. The thickest biotubes were as strong as bovine pericardium and can be used as an alternative trachea graft because of their adequate lumen-holding force.

Heparin-Coated Grafts Reduce Mortality in Pediatric Patients Receiving Systemic-to-Pulmonary Shunts.

We aimed to evaluate the outcomes of systemic-to-pulmonary (SP) shunt procedures utilizing heparin-coated (HC) polytetrafluoroethylene (PTFE) vascular grafts compared to uncoated (non-HC) grafts, in order to observe any benefits in pediatric patients. Our institution switched from using non-HC grafts to HC grafts in March 2011. We conducted a retrospective review of consecutive pediatric patients receiving SP shunts from May 2008 to December 2015. Perioperative variables including baseline characteristics, morbidity, mortality, and blood product utilization were evaluated between the HC and non-HC groups. A total of 142 pediatric patients received SP shunts during the study period: 69 patients received HC shunts and 73 patients received non-HC shunts. The HC group had significantly fewer desaturation or arrest events (P < 0.01), fewer shunt occlusions/thromboses (P < 0.01). There was no statistically significant difference in unplanned reoperations between groups (P = 0.18). The HC group demonstrated significantly lower overall 30-day mortality (P < 0.01), as well as shunt-related mortality (P < 0.01). The HC group had significantly lower postoperative packed red blood cell utilization as compared to the non-HC group (P < 0.01). In this study, pediatric patients receiving HC PTFE grafts in SP shunts demonstrated significantly lower shunt-related mortality. The majority of HC grafts remained patent. These findings suggest that HC grafts used in SP shunt procedures may benefit pediatric patients in terms of efficacy and outcomes.

[Effectiveness of biological prosthesis for femoro-femoral bypass in high risk patients]. / Éffektivnost' biologicheskogo proteza pri bedrenno-bedrennom shuntirovanii u lits s vysokim operatsionnym riskom.

AIM: To compare synthetic and biological prostheses for femoral bypass surgery. MATERIAL AND METHODS: There were 40 patients with critical ischemia of lower extremities due to atherosclerotic lesion of aorto-iliac segment and severe comorbidities. They were divided into 2 groups by 20 patients. C-shaped femoro-femoral bypass with synthetic polytetrafluoroethylene and lavsan prostheses was performed in the first group and S-shaped bypass procedure with biological prosthesis from the internal thoracic arteries of the bull - in the second group. RESULTS: Biological prosthesis is associated with reduced early postoperative morbidity by 10%, late graft thrombosis incidence by 20% and increased physical and psychological health by 7.1%. CONCLUSION: S-shaped femoro-femoral bypass with a biological prosthesis from the internal thoracic arteries of the bull is pathogenetically substantiated and effective.

Drug-eluting balloons and uncoated balloons perform equally to rescue infrainguinal autologous bypasses at risk.

OBJECTIVE: Endovascular treatment of a significant stenosis in an infrainguinal autologous bypass prevents bypass occlusion and improves bypass patency. Drug-eluting balloons (DEBs) have been proven to possess antirestenotic features in the treatment of femoropopliteal stenoses and occlusions. This study evaluated the effects of DEB angioplasty vs uncoated balloon (UCB) angioplasty to rescue infrainguinal autologous bypass grafts at risk (BAR). METHODS: The study included all consecutive patients treated endovascularly for BAR from December 1, 2012, to July 31, 2015. As of April 1, 2014, the primary treatment of BAR was changed from UCBs to DEBs. Patients treated with DEBs were prospectively recorded in a database and retrospectively analyzed. Patients treated with UCBs were retrospectively collected from a historical cohort with a similar inclusion period length as the DEB cohort. The follow-up scheme did not differ between the two groups. The primary end point was the combined end point of freedom from recurrent stenosis or bypass occlusion. Secondary end points were primary assisted patency, secondary patency, technical success, major amputation, and mortality. RESULTS: Twenty-one patients were treated in the DEB group and 18 were treated in the UCB group. The two groups were evenly distributed in demographics, bypass, treatment, and lesion characteristics. No statistically significant differences were found in the combined end point of freedom from recurrent stenosis and the occlusion rate after 1 year between the UCB group (77.8%) and the DEB group (80.0%; P = .76). After 1 year, the primary assisted patency rate was 88.2% in the UCB group vs 95.2% in the DEB group (P = .47), and the secondary patency rate was 94.1% in the UCB group vs 95.2% in the DEB group (P = .91). During follow-up, restenosis developed in four patients (22.2%) in the UCB group and in four patients (19.0%) in the DEB group (P = .80). One bypass (5.6%) in the UCB group and one bypass (4.8%) in the DEB group occluded during follow-up (P = .884). CONCLUSIONS: DEBs and UCBs perform equally in the treatment of significant stenosis in infrainguinal autologous bypasses with regard to freedom from restenosis or bypass occlusion, primary assisted patency, and secondary patency at 1 year. We suggest using a less expensive UCB in the treatment of BAR.

Monoether-Tagged Biodegradable Polycarbonate Preventing Platelet Adhesion and Demonstrating Vascular Cell Adhesion: A Promising Material for Resorbable Vascular Grafts and Stents.

We developed a biodegradable polycarbonate that demonstrates antithrombogenicity and vascular cell adhesion via organocatalytic ring-opening polymerization of a trimethylene carbonate (TMC) analogue bearing a methoxy group. The monoether-tagged polycarbonate demonstrates a platelet adhesion property that is 93 and 89% lower than those of poly(ethylene terephthalate) and polyTMC, respectively. In contrast, vascular cell adhesion properties of the polycarbonate are comparable to those controls, indicating a potential for selective cell adhesion properties. This difference in the cell adhesion property is well associated with surface hydration, which affects protein adsorption and denaturation. Fibrinogen is slightly denatured on the monoether-tagged polycarbonate, whereas fibronectin is highly activated to expose the RGD motif for favorable vascular cell adhesion. The surface hydration, mainly induced by the methoxy side chain, also contributes to slowing the enzymatic degradation. Consequently, the polycarbonate exhibits decent blood compatibility, vascular cell adhesion properties, and biodegradability, which is promising for applications in resorbable vascular grafts and stents.

Peculiarities of vitalization of grafts made of porous polytetrafluoroethylene in reconstruction of major veins (an experimental study). / Osobennosti vitalizatsii protezov iz poristogo politetraftorétilena pri rekonstruktsii magistral'nykh ven (éksperimental'noe issledovanie).

Increased incidence of locally disseminated malignant neoplasms with invasion of major veins compels modern surgery to search for an optimal material for reconstruction of major veins. Presented herein are the results of an experimental study aimed at exploring patency and peculiarities of vitalization of grafts made of porous polytetrafluoroethylene (7th generation, 2010) manufactured by the Closed Joint Stock Company 'Research and Production Complex 'Ecoflon' (St. Petersburg, Russia) with an internal diameter measuring 4.0 mm and used for reconstruction of major veins and arteries with a follow up period up to 270 days. Vitalization of porous polytetrafluoroethylene grafts in the venous position is comparable to that in the arterial position, having similar patterns. Both in the arterial and venous position, vitalization of the graft proceeds at the expense of 'crawling' of the neointima from the anastomoses to the centre of the graft. To distinctive peculiarities of vitalization of grafts in the venous position belong statistically significantly larger thickness of the neointima in the venous position at all stages of the study, lack of statistically significant difference of the neointimal thickness near the edges and in the central part of the graft in the venous position at 270 days. Neither thromboses nor haemodynamically meaningful stenoses of the porous polytetrafluoroethylene grafts and anastomoses in the venous position, despite low velocity of blood flow and its laminar pattern, were observed at any terms of follow up. The obtained findings are indicative of the possibility and validity of using porous polytetrafluoroethylene grafts for reconstruction of major veins in clinical practice.

[Method of forming a distal anastomosis with an autovenous cuff]. / Sposob formirovaniia distal'nogo anastomoza s autovenoznoi manzhetoi.

Presented herein is a brief review of the world literature dedicated to methods of formation of composite arterial anastomoses in the femoropopliteal-tibial region The most justified is considered the use of a composite shunt formed proximally from a synthetic vascular graft made of polytetrafluoroethylene and distally with an extension from a portion of the suitable for reconstruction autovein (the so-called autovenous cuff of patch). The use of an autovenous cuff is more physiological since it provides closer correspondence of the diameters of the distal anastomosis being applied between the artery and autovenous extension, as well as contributes to creation of more adequate haemodynamic conditions in the shunt. Also analysed is the technique of performing the previously suggested anastomoses, demonstrating their main disadvantages. This is followed by describing a new original method of formation of a distal anastomosis using an autovenous insert, showing its advantages, with the main amongst them being the presence of only two vascular sutures and a decrease in the possibility of the onset and development of turbulence in the zone of the anastomosis. A conclusion is drawn that the suggested method contributes to decreasing the duration of the main stage of the operation, decreases the probability of technical defects and reduces the risk for the development of postoperative complications associated with impairments of the processes of haemodynamics in the zone of the anastomosis formed.

A Comparison between splenic fossa and subhepatic fossa auxiliary partial heterotopic liver transplantation in a porcine model.

To test the alternative possible locations for the placement of a liver graft and the relevant surgical technique issues, we developed a porcine model of auxiliary partial heterotopic liver transplantation (APHLT) and evaluated the difference between 2 styles of liver transplantation, either subhepatic fossa or splenic fossa APHLT, by comparing survival and biochemical indexes. Thirty-eight miniature pigs were randomly divided into 2 groups. A left hemihepatic graft without the middle hepatic vein (HV) was procured from the living donor. In group A (n = 9), an 8 mm diameter polytetrafluoroethylene (PTFE) graft approximately 2.5 cm long was connected to the left HV while another PTFE graft of the same size was connected to the left portal vein (PV). The liver graft was implanted in the right subhepatic fossa following splenectomy and right nephrectomy. In group B (n = 10), a PTFE graft of the same size was connected to the left HV while the liver graft was implanted in the splenic fossa following splenectomy and left nephrectomy. Survival rate and complications were observed at 2 weeks after transplantation. Data were collected from 5 animals in group A and 6 animals in group B that survived longer than 2 weeks. The liver function and renal function of the recipients returned to normal at 1 week after surgery in both groups. Eighty-eight percent (14/16) of the PTFE grafts remained patent at 2 weeks after surgery, but 44% of the PTFE grafts (7/16) developed mural thrombus. No significant differences in the survival rate and biochemistry were found between the 2 groups. In conclusion, the splenic fossa APHLT can achieve beneficial outcomes similar to the subhepatic fossa APHLT in miniature pigs, although it also has a high morbidity rate due to hepatic artery thrombosis, PV thrombosis, and PTEF graft mural thrombus formation. Liver Transplantation 22 812-821 2016 AASLD.

Surgical Exposure to Control the Distal Internal Carotid Artery at the Base of the Skull during Carotid Aneurysm Repair.

Extracranial carotid artery aneurysms are rare. Treatment options for these lesions include endovascular interventions, such as coiling and stenting, or surgical reconstruction, such as resection and primary reanastomosis, or interposition bypass grafting. In this report, we describe the surgical technique used to perform surgical repair of an internal carotid artery aneurysm extending up to the base of the skull. Anterior exposure of the infratemporal fossa and distal control of the carotid artery at the level of the carotid canal was achieved through a transcervical approach, performing double mandibular osteotomies with superior reflection of the middle mandibular section.