Expanded Polytetrafluoroethylene Grafts Research Articles

Long-term outcomes of below-the-knee bypass surgery using heparin-bonded expanded polytetrafluoroethylene grafts.

To report the outcomes of below-the-knee (BK) bypass surgery using heparin-bonded expanded polytetrafluoroethylene (ePTFE) grafts, performed in two centers since its launch in Japan. We conducted a retrospective analysis of databases from two medical centers, evaluating 51 limbs in 42 consecutive patients with peripheral arterial disease (PAD), who underwent BK bypass surgery using heparin-bonded ePTFE grafts between October, 2013 and April, 2023. Thirty-three limbs (64.7%) were classified as Rutherford category 4-6 and 33 limbs (64.7%) had a history of ipsilateral revascularization. Technical success was achieved in 98% of the patients. The 30day mortality rate was 2.4% (n = 1) and the overall 30day complication rate was 9.5% (n = 4). The median follow-up period was 38 (interquartile range 13-67) months. Three patients required major amputation and 14 died during follow-up. Primary patency rates at 1, 3, and 5years were 67.8%, 57.5%, and 46.5%, respectively, while secondary patency rates for these periods were 84.6%, 70.0%, and 66.0%, respectively. Overall survival rates at 1, 3, and 5years were 90.1%, 74.5%, and 70.9%, respectively. BK bypass surgery using heparin-bonded ePTFE graft is a viable and durable option for patients with PAD, who are deemed unsuitable for autologous vein bypass surgery.

Retrospective evaluation of three types of expanded polytetrafluoroethylene grafts for upper limb vascular access

Currently, three expanded polytetrafluoroethylene (ePTFE) prosthetic graft types are most commonly used for patients with end-stage kidney disease (ESKD) who require long-term vascular access for hemodialysis. However, studies comparing the three ePTFE grafts are limited. This study compared the clinical efficacy and postoperative complications of three ePTFE prosthetic graft types used for upper limb arteriovenous graft (AVG) surgery among patients with ESKD. Patients with ESKD requiring upper limb AVG surgery admitted to our center between January 2016 and September 2019 were enrolled. Overall, 282 patients who completed the 2-year follow-up were included and classified into the following three groups according to the ePTFE graft type: the GPVG group with the PROPATEN® graft, the GAVG group with the straight-type GORE® ACUSEAL, and the BVVG group with the VENAFLO® II. The patency rate and incidence of access-related complications were analyzed and compared between groups. The patients were followed up postoperatively, and data were collected at 6, 12, 18, and 24 months postoperatively. Respective to these follow-up time points, in the GPVG group, the primary patency rates were 74.29%, 65.71%, 51.43%, and 42.86%; the assisted primary patency rates were 85.71%, 74.29%, 60.00%, and 48.57%; and the secondary patency rates were 85.71%, 80.00%, 71.43%, and 60.00%. In the GAVG group, the primary patency rates were 73.03%, 53.93%, 59.42%, and 38.20%; the assisted primary patency rates were 83.15%, 68.54%, 59.55%, and 53.93%; and the secondary patency rates were 85.39%, 77.53%, 68.54%, and 62.92%, respectively. In the BVVG group, the primary patency rates were 67.24%, 53.45%, 41.38%, and 29.31%; the assisted primary patency rates were 84.48%, 67.24%, 55.17%, and 44.83%; and the secondary patency rates were 86.21%, 81.03%, 68.97%, and 60.34%, respectively. The differences in patency rates across the three grafts were not statistically significant. Overall, 18, 4, and 12 patients in the GPVG, GAVG, and BVVG groups, respectively, experienced seroma. Among the three grafts, GORE® ACUSEAL had the shortest anastomosis hemostatic time. The first cannulation times for the three grafts were GPVG at 16 (±8.2), GAVG at 4 (±4.9), and BVVG at 18 (±12.7) days. No significant difference was found in the postoperative swelling rate between the GPVG group and the other two groups. Furthermore, no statistically significant differences were found across the three graft types regarding postoperative vascular access stenosis and thrombosis, ischemic steal syndrome, pseudoaneurysm, or infection. In conclusion, no statistically significant differences in the postoperative primary, assisted primary, or secondary graft patency rates were observed among the three groups. A shorter anastomosis hemostatic time, first cannulation time, and seroma occurrence were observed with the ACUSEAL® graft than with its counterparts. The incidence of upper extremity swelling postoperatively was greater with the PROPATEN® graft than with the other grafts. No statistically significant differences were observed among the three grafts regarding the remaining complications.

Outcomes of Cold Stored Saphenous Vein Allografts for Haemodialysis Vascular Access

The aim of this study was to evaluate the outcome of cold stored saphenous vein allografts (CSVAs) for haemodialysis vascular access. A retrospective, two centre study was conducted between January 2016 and December 2020 of all patients who had CSVA placement for haemodialysis vascular access. Primary, primary assisted, and secondary patency were analysed, as well as procedural complications and re-interventions. A total of 109 patients (n = 55 women) with a mean age of 67.2 ± 13.6 years, with no options for creating an autogenous arteriovenous fistula, were included in the study. At 1 year, primary, primary assisted, and secondary patency were 38%, 59%, and 73%, respectively; and at 2 years they were 20%, 43%, and 55%, respectively. During a mean follow up period of 26 ± 18 months, five patients (4.6%) had an access infection, with no related death. During the follow up period, 32 patients (29.4%) died and 13 patients (11.9%) underwent a kidney transplant. None of these patients showed immunoconversion before transplantation. The cumulative incidence of adverse events by the Fine-Gray method was calculated. Considering competing risks (death and renal transplantation), 9% of patients lost their vascular access at 1 year and 18% at 2 years. Moreover, 57.8% patients had stenosis, mainly on the outflow (45.9%), and 49.5% had thrombosis. With a comparable patency rate associated with a low rate of infection, CSVA offers a potential alternative to expanded polytetrafluoroethylene grafts. This creates haemodialysis vascular access when the venous capital is exhausted in patients with reported risk factors for vascular access infection, i.e., insertion in the thigh, advance age, diabetes mellitus, immunocompromised state, obesity, or revision of an infected prosthetic graft.

Intraoperative Transit-Time Flow as a Predictor of Failure after Infrainguinal Revascularization with Heparin-Bonded Expanded Polytetrafluoroethylene Graft

The heparin-bonded expanded polytetrafluoroethylene (He-ePTFE) conduit is an option for patients requiring infrainguinal revascularization (iIR), but the risk of failure may be unpredictable, especially in cases with poor run-off. Intraoperative transit-time flow (TTF) provides an automated and quantitative analysis of flow and may serve as an adjunct evaluation during surgical revascularization. The aim of this study was to assess TTF in patients undergoing iIR with He-PTFE at 3 referral hospitals and to establish a predictive flow threshold for graft occlusion. A prospective registry initiated in 2020 enrolled patients undergoing iIR using He-PTFE for critical limb ischemia or severe claudication, and TTF measurement was analyzed. Preoperative assessments of anatomical and clinical characteristics were available for all patients. The HT353 Optima Meter (Transonic Systems Inc., Ithaca, NY, USA) was used in all procedures according to a standardized protocol. The institutional ethics committee approved the study. A predictive model using receiver operating characteristic curve analysis was utilized to establish the threshold of flow, and variables were compared. Anatomical and clinical evaluation were reported according to Rutherford grade, Global Limb Anatomic System and Wound, Ischemia, and foot Infection classification. The main outcome considered was the correlation between TTF and graft occlusion. Secondary outcomes included survival, other predictors of graft occlusion, freedom from major adverse cardiovascular events, and freedom from major amputation. Among 68 patients, 55.8% had Rutherford 5-6, 45.6% had Global Limb Anatomic System 3 and 73.5% had Wound, Ischemia, and foot Infection 3-4. Distal anastomosis was at tibial level in 23.5% and mean diameter of conduit was 6.4mm. Basal and postoperative TTF were 27.8±15.6ml/min and 109.0±53.0 ml/min, respectively. After a mean follow-up of 18±13months, 7 (10.9%) patients presented graft occlusion and 5 (7.8%) required major amputation. TTF threshold=80ml/min revealed a sensitivity and specificity of 81.8% (95% confidence interval 48.2-97.7) and 80.7% (95% confidence interval 68.1-90.0) respectively, and it was selected as cut-off for graft occlusion. Freedom from graft occlusion in patients with TTF >80ml/min vs. TTF ≤80ml/min at 6, 12, and 24months was 95.7% (standard error (SE)=0.030) vs. 65.5% (SE=0.115), 95.7% (SE=0.030) vs. 58.9% (SE=0.120) and 90.9% (SE=0.054) vs. 51.6% (SE=0.126), P=0.0003. No statistical difference in primary patency, secondary patency and limb salvage was observed. At multivariate analysis, distal anastomosis at tibial vessel (odds ratio 8.50) and TTF ≤80ml/min (odds ratio 9.39) were independent predictors of graft occlusion. These results suggest that TTF may serve as a valuable tool in the management of iIR. A TTF measurement of ≤80ml/min should be regarded as a predictor of graft occlusion, prompting consideration of additional intraoperative maneuvers to enhance arterial flow. Caution should be exercised in patients requiring direct tibial artery revascularization, as it represents a predictor of failure independent of TTF levels. Larger cohorts of patients and longer follow-up periods are necessary to confirm these findings.

Long-Term Outcomes of a Japanese Prospective Multicenter Registry Using a Heparin-Bonded Expanded Polytetrafluoroethylene Graft for Above-the-Knee Femoropopliteal Bypasses.

Despite the widespread use of PROPATEN®, a bioactive heparin-bonded expanded polytetrafluoroethylene graft, in bypass surgery, there are only a few reports of long-term results. We evaluated the long-term results of PROPATEN®use for above-knee femoropopliteal bypass (AKFPB).Methods and Results: After PROPATEN®-based AKFPB, patients were prospectively registered at 20 Japanese institutions between July 2014 and October 2017 to evaluate long-term results. During the median follow-up of 76 months (interquartile range 36-88 months) for 120 limbs (in 113 patients; mean [±SD] age 72.7±8.1 years; 66.7% male; ankle-brachial index [ABI] 0.45±0.27; lesion length 26.2±5.7 cm; chronic limb-threatening ischemia in 45 limbs), there were 8 major amputations; however, clinical improvement was sustained (mean [±SD] ABI 0.87±0.23) and the Rutherford classification grade improved in 105 (87.5%) limbs at the latest follow-up. At 8 years, the primary patency, freedom from target-lesion revascularization, secondary patency, survival, and amputation-free survival, as estimated by the Kaplan-Meier method, were 66.3±4.8%, 71.5±4.4%, 86.5±3.4%, 53.1±5.0%, and 47.4±5.3%, respectively. This multicenter prospective registry-based analysis showed sustained excellent clinical improvement and secondary patency for up to 8 years following PROPATEN®-based AKFPB. PROPATEN®constitutes a durable and good revascularization option for complex superficial femoral artery lesions, especially when endovascular treatment is inappropriate or an adequate venous conduit is unavailable.

A Systematic Review and Meta-Analysis of Heparin-Bonded Expanded Polytetrafluoroethylene Grafts for Below-The-Knee Femoral Bypass Surgery

Heparin-bonded expanded polytetrafluoroethylene (hb-ePTFE) synthetic grafts are an alternative to autologous vein grafts (AVG) for surgical bypass interventions in lower limb peripheral arterial disease (LLPAD). However, the clinical benefits of hb-ePTFE grafts have not been reviewed systematically for patients undergoing below-the-knee (BK) surgical bypass. This study aimed to meta-analyze available data on the utility of hb-ePTFE in patients undergoing BK surgical bypass. Medline, Embase, and Cochrane databases were searched, restricted to material in English with no date restriction. In addition, proceedings from relevant congresses were screened going back 2years. The search was performed in December 2021. Eligible studies included prospective or retrospective comparative studies or prospective single-arm cohorts with an hb-ePTFE arm. Methodological quality was assessed with the ROBINS-I criteria. Outcomes included primary patency, amputation/limb salvage, and overall survival. Clinical outcomes were expressed as event rates. Studies were compared using meta-analysis to generate a standardized mean event rate for each outcome, with its 95% confidence interval (95% CI), using a random-effects model. Following deduplication, 10,263 records were identified and 261 were assessed as full texts. No prospective comparative studies were identified. The level of evidence was uniformly low. Seventeen publications describing data from 9 individual patient cohorts met the inclusion criteria. These cohorts included a total of 1,452 patients undergoing BK surgical bypass with hb-ePTFE. The primary patency rate was 78.9% [95% CI: 72.2-85.7%] at 1year, 68.2% [95% CI: 62.8-73.6%] at 2years, decreasing to 48.0% [95% CI: 27.3-68.7%] at 5years. The secondary patency rate was 84.8% [95% CI: 77.0-92.5%] at 1year and 68.9% [95% CI: 43.0-94.9%] at 3years; the 1-year limb salvage rate was 88.3% [95% CI: 79.6-97.1%] at 1year and 79.0% [95% CI: 56.7-100%] at 3years. In patients undergoing BK bypass surgery, hb-ePTFE synthetic grafts, compared to uncoated grafts, perform well for patency and limb salvage. However, the quality of the evidence is low, and well-performed randomized clinical trials are needed to inform clinical decision-making on the choice of synthetic graft.

Tissue engineered vascular grafts are resistant to the formation of dystrophic calcification

Advancements in congenital heart surgery have heightened the importance of durable biomaterials for adult survivors. Dystrophic calcification poses a significant risk to the long-term viability of prosthetic biomaterials in these procedures. Herein, we describe the natural history of calcification in the most frequently used vascular conduits, expanded polytetrafluoroethylene grafts. Through a retrospective clinical study and an ovine model, we compare the degree of calcification between tissue-engineered vascular grafts and polytetrafluoroethylene grafts. Results indicate superior durability in tissue-engineered vascular grafts, displaying reduced late-term calcification in both clinical studies (p < 0.001) and animal models (p < 0.0001). Further assessments of graft compliance reveal that tissue-engineered vascular grafts maintain greater compliance (p < 0.0001) and distensibility (p < 0.001) than polytetrafluoroethylene grafts. These properties improve graft hemodynamic performance, as validated through computational fluid dynamics simulations. We demonstrate the promise of tissue engineered vascular grafts, remaining compliant and distensible while resisting long-term calcification, to enhance the long-term success of congenital heart surgeries.

Long-term Results of a Heparin-bonded Expanded Polytetrafluoroethylene Grafts for Above-the-knee Femoropopliteal Bypasses: A Japanese Prospective Multicenter Registry

Propaten (WL Gore & Associates, Flagstaff, AZ) is a bioactive heparin-bonded expanded polytetrafluoroethylene graft widely used for bypass surgery; however, its long-term results are yet to be established. In this study, we evaluated the long-term results of Propaten for above-the-knee femoropopliteal bypasses (AKFPB) using a Japanese prospective multicenter registry. In this prospective single-arm multicenter registry, 120 limbs (113 patients) underwent AKFPB for superficial femoral artery (SFA) lesion in 20 Japanese institutions between July 2014 and October 2017. We evaluated the long-term results by estimating primary patency (PP), secondary patency (SP), freedom from target lesion revascularization (TLR), and freedom from death at 6 years using the Kaplan-Meier method. Factors associated with the risk for the loss of PP were investigated using the Cox proportional hazards regression model. Baseline characteristics of 120 limbs are summarized in Table. Mean lesion length was 26.2 ± 5.7 cm, chronic limb-threatening ischemia was present in 45 limbs (37.5%), and only 35 limbs (29.2%) had all three runoff vessels patent. Technical success was achieved in all cases, and 49 limbs (40.8%) had concomitant additional procedure, mainly endovascular treatment (EVT), and cuffed distal anastomosis was employed in 93 limbs (77.5%). There were eight perioperative complications (6.7%), however, mean ankle brachial index (ABI) improved from 0.45 ± 0.27 to 0.96 ± 0.14, and improvement in Rutherford classification (RC) was achieved in 98 limbs (81.7%) at 30 days. Clinical improvement was sustained at the latest follow-up as mean ABI was 0.87 ± 0.23, and improvement in RC was achieved in 105 limbs (87.5%). PP, freedom from TLR, SP, and freedom from death at 6 years were 66.1% ± 4.9%, 72.4% ± 4.5%, 85.6% ± 3.6%, and 62.9% ± 4.8%, respectively (Fig 1). As for the factors associated with the risk for the loss of PP, prior coronary disease (unadjusted hazard ratio [HR], 2.57; 95% confidence interval [CI], 1.09-4.36; P = .006), hemodialysis (unadjusted HR, 2.62; 95% CI, 1.19-5.57; P = .02), three runoff vessels patent (unadjusted HR, 0.48; 95% CI, 0.22-1.06; P = .07), and cuffed distal anastomosis (unadjusted HR, 0.51; 95% CI, 0.25-1.07; P = .08) were selected for the multivariate analysis from the result of univariate analysis; however, only prior coronary disease remained significant (adjusted HR, 2.18; 95% CI, 1.09-4.36; P = .03). Long-term sustained clinical improvement and acceptable SP was achieved for AKFPB using Propaten. When good venous conduit is unavailable, AKFPB using Propaten is a reasonable revascularization option for complex SFA lesions, especially when EVT is inappropriate.TablePatients’ demographics and characteristicsVariableN = 120 limbsAge, years72.7 ± 8.1Male sex81 (67.5%)Body mass index, kg/m222.5 ± 3.8Rutherford classification 230 (25.0%) 345 (37.5%) 413 (10.8%) 531 (25.8%) 61 (0.8%)Ankle brachial index0.45 ± 0.27Number of runoff vessels 01 (0.8) 143 (35.8) 241 (34.2) 335 (29.2)TASC II classifications A0 (0.0) B6 (5.0) C20 (16.7) D94 (78.3)Lesion length, cm26.2 ± 5.7Outflow popliteal artery diameter, mm4.9 ± 1.1Key comorbidities and medical history Smoking, current31 (25.8%) Smoking, former67 (55.8%) Prior superficial femoral artery treatment32 (26.7%) Arterial hypertension91 (75.8%) Diabetes mellitus63 (52.5%) Dyslipidemia57 (47.5%) Chronic kidney disease (eGFR <60 mL/min)69 (57.5%) Hemodialysis17 (14.2%) Prior coronary disease38 (31.7%) Prior cerebrovascular disease24 (20.8%) Serum albumin <3.0 g/dL24 (20.8%)eGFR, Estimated glomular filtration rate.Categorical variables are presented as number (%), and continuous variables are presented as mean ± standard deviation. Open table in a new tab

Evaluation of vascular repair by tissue-engineered human acellular vessels or expanded polytetrafluoroethylene grafts in a porcine model of limb ischemia and reperfusion.

This study evaluated performance of a tissue-engineered human acellular vessel (HAV) in a porcine model of acute vascular injury and ischemia. The HAV is an engineered blood vessel consisted of human vascular extracellular matrix proteins. Limb reperfusion and vascular outcomes of the HAV were compared with those from synthetic expanded polytetrafluoroethylene (ePTFE) grafts. Thirty-six pigs were randomly assigned to four treatment groups, receiving either the HAV or a PTFE graft following a hind limb ischemia period of either 0 or 6 hours. All grafts were 3-cm-long interposition 6-mm diameter grafts implanted within the right iliac artery. Animals were not immunosuppressed and followed for up to 28 days after surgery. Assessments performed preoperatively and postoperatively included evaluation of graft patency, hind limb function, and biochemical markers of tissue ischemia or reperfusion injury. Histological analysis was performed on explants to assess host cell responses. Postoperative gait assessment and biochemical analysis confirmed that ischemia and reperfusion injury were caused by 6-hour ischemia, regardless of vascular graft type. Hind limb function and tissue damage biomarkers improved in all groups postoperatively. Final patency rates at postoperative day 28 were higher for HAV than for ePTFE graft in both the 0-hour (HAV, 85.7%; ePTFE, 66.7%) and 6-hour (HAV, 100%; ePTFE, 75%) ischemia groups, but these differences were not statistically significant. Histological analyses identified some intimal hyperplasia and host reactivity to the xenogeneic HAV and also to the synthetic ePTFE graft. Positive host integration and vascular cell infiltration were identified in HAV but not ePTFE explants. Based on the functional performance and the histologic profile of explanted HAVs, this study supports further investigation to evaluate long-term performance of the HAV when used to repair traumatic vascular injuries.

Biological mechanisms of infection resistance in tissue engineered blood vessels compared to synthetic expanded polytetrafluoroethylene grafts

ObjectiveSynthetic expanded polytetrafluoroethylene (ePTFE) grafts are known to be susceptible to bacterial infection. Results from preclinical and clinical studies of bioengineered human acellular vessels (HAVs) have shown relatively low rates of infection. This study evaluates the interactions of human neutrophils and bacteria with ePTFE and HAV vascular conduits to determine whether there is a correlation between neutrophil-conduit interactions and observed differences of their infectivity in vivo. MethodsA phase III comparative clinical study between investigational HAVs (n = 177) and commercial ePTFE grafts (n = 178) used for hemodialysis access (ClinicalTrials.gov Identifier: NCT02644941) was evaluated for conduit infection rates followed by histological analyses of HAV and ePTFE tissue explants. The clinical histopathology of HAV and ePTFE conduits reported to be infected was compared with immunohistochemistry of explanted materials from a preclinical model of bacterial contamination. Mechanistic in vitro studies were then conducted using isolated human neutrophils seeded directly onto HAV and ePTFE materials to analyze neutrophil viability, morphology, and function. ResultsClinical trial results showed that the HAV had a significantly lower (0.93%; P = .0413) infection rate than that of ePTFE (4.54%). Histological analysis of sections from infected grafts explanted approximately 1 year after implantation revealed gram-positive bacteria near cannulation sites. Immunohistochemistry of HAV and ePTFE implanted in a well-controlled rodent infection model suggested that the ePTFE matrix permitted bacterial infiltration and colonization but may be inaccessible to neutrophils. In the same model, the HAV showed host recellularization and lacked detectable bacteria at the 2-week explant. In vitro results demonstrated that the viability of human neutrophils decreased significantly upon exposure to ePTFE, which was associated with neutrophil elastase release in the absence of bacteria. In contrast, neutrophils exposed to the HAV material retained high viability and native morphology. Cocultures of neutrophils and Staphylococcus aureus on the conduit materials demonstrated that neutrophils were more effective at ensnaring and degrading bacteria on the HAV than on ePTFE. ConclusionsThe HAV material seems to demonstrate a resistance to bacterial infection. This infection resistance is likely due to the HAV's native-like material composition, which may be more biocompatible with host neutrophils than synthetic vascular graft material.

Aortic-tibial transiliac wing extra-anatomic bypass with distal fistula for treatment of an infected deep femoral pseudoaneurysm.

Transiliac wing bypass has been reported to be a viable extra-anatomic alternative technique for patients presenting with a history of groin infection or irradiation.1Enzmann F.K. Nierlich P. Eder S.K. Aspalter M. Dabernig W. Aschacher T. et al.Trans-iliac bypass grafting for vascular groin complications.Eur J Vasc Endovasc Surg. 2019; 58: 930-935Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Of the 32 reported cases, only two patients had undergone transiliac aortic–tibial or iliotibial bypass.2Sekanina G. Lemminger F. Bruecher D. Iliaco-crural bypass through a borehole in the iliac fossa as extra-anatomic vascular bypass in infected inguinal canal and posterior aspect of the knee.Chirurg. 1995; 66: 142-145PubMed Google Scholar,3Heldenberg E. Lorber J. Cheyn D. Bass A. Transiliac wing alternate route bypass for infected groin vascular graft.J Vasc Surg. 2014; 60: 504-505Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar We report the case of a 72-year-old man with a complex history of multiple lower limb revascularizations, who had been admitted for a deep femoral infected anastomotic pseudoaneurysm (A) and left chronic limb threatening ischemia. Computed tomography showed chronic occlusions at the femoropopliteal level, with a previous thrombosed obturator canal bypass. The only patent lower leg artery was the posterior tibial artery (PTA) from its mid-third to the foot.A transiliac wing aortic–tibial prosthetic bypass was performed through a pararectal retroperitoneal approach (B/Cover). The infrarenal aorta and common iliac arteries were cross-clamped before implanting an 8-mm expanded polytetrafluoroethylene graft soaked in rifampicin at the terminal aorta level. It was tunneled into the retroperitoneal space, over the psoas muscle. A U-shape osteotomy was performed at the anterior left iliac wing border through a second lateral incision to guide the bypass. Another incision was made at the lateral side of the thigh to guide the graft route between the femoral condyles. It was associated with a distal arteriovenous bypass between the PTA and a fibular vein (C), before the distal anastomosis of the aortic–tibial bypass, to partially deviate the aortic blood flow from the PTA into the venous circulation.The second part of the procedure consisted of deep femoral pseudoaneurysm repair. It was developed at the distal anastomosis level of the thrombosed obturator canal bypass, which was removed to the obturator canal during the same procedure. The deep femoral artery was then ligated with 5-0 polypropylene suture. Transiliac wing bypass has been reported to be a viable extra-anatomic alternative technique for patients presenting with a history of groin infection or irradiation.1Enzmann F.K. Nierlich P. Eder S.K. Aspalter M. Dabernig W. Aschacher T. et al.Trans-iliac bypass grafting for vascular groin complications.Eur J Vasc Endovasc Surg. 2019; 58: 930-935Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Of the 32 reported cases, only two patients had undergone transiliac aortic–tibial or iliotibial bypass.2Sekanina G. Lemminger F. Bruecher D. Iliaco-crural bypass through a borehole in the iliac fossa as extra-anatomic vascular bypass in infected inguinal canal and posterior aspect of the knee.Chirurg. 1995; 66: 142-145PubMed Google Scholar,3Heldenberg E. Lorber J. Cheyn D. Bass A. Transiliac wing alternate route bypass for infected groin vascular graft.J Vasc Surg. 2014; 60: 504-505Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar We report the case of a 72-year-old man with a complex history of multiple lower limb revascularizations, who had been admitted for a deep femoral infected anastomotic pseudoaneurysm (A) and left chronic limb threatening ischemia. Computed tomography showed chronic occlusions at the femoropopliteal level, with a previous thrombosed obturator canal bypass. The only patent lower leg artery was the posterior tibial artery (PTA) from its mid-third to the foot. A transiliac wing aortic–tibial prosthetic bypass was performed through a pararectal retroperitoneal approach (B/Cover). The infrarenal aorta and common iliac arteries were cross-clamped before implanting an 8-mm expanded polytetrafluoroethylene graft soaked in rifampicin at the terminal aorta level. It was tunneled into the retroperitoneal space, over the psoas muscle. A U-shape osteotomy was performed at the anterior left iliac wing border through a second lateral incision to guide the bypass. Another incision was made at the lateral side of the thigh to guide the graft route between the femoral condyles. It was associated with a distal arteriovenous bypass between the PTA and a fibular vein (C), before the distal anastomosis of the aortic–tibial bypass, to partially deviate the aortic blood flow from the PTA into the venous circulation. The second part of the procedure consisted of deep femoral pseudoaneurysm repair. It was developed at the distal anastomosis level of the thrombosed obturator canal bypass, which was removed to the obturator canal during the same procedure. The deep femoral artery was then ligated with 5-0 polypropylene suture. Appendix

Early and mid-term outcomes of open popliteal artery aneurysm repair with prosthetic grafts

ObjectiveThe aim of the present study was to assess the early and mid-term outcomes of open surgical repair (OSR) for popliteal artery aneurysms (PAAs) with prosthetic grafts. MethodsThe pre-, intra-, and postoperative data for all the patients who had undergone OSR for PAAs with prosthetic grafts at our Institution between January 2009 and July 2019 were included in a prospectively maintained database, which was retrospectively analyzed. Primary patency was defined as uninterrupted flow (<50% stenosis) in the graft with no additional procedures performed. Secondary patency was defined as the restoration of graft patency. ResultsA total of 82 patients had undergone OSR for 104 PAAs (median age, 71 years; interquartile range [IQR], 67-78 years; 82 men) with prosthetic grafts. Of the 104 PAAs, 72 (68%) had been asymptomatic. The median diameter was 30 mm (IQR, 24-37 mm). A medial approach was used for 35 PAAs (34%) and a posterior approach for 69 (65%). The repairs consisted of aneurysmectomy or aneurysm ligation without removal with an interposition graft placed and end-to-end anastomoses. The median operative time was 120 minutes (IQR, 103-142 minutes). The estimated blood loss was 281 mL (IQR, 150-281 mL). Only one patient treated with a posterior approach sustained a permanent peroneal nerve lesion. A second patient also treated via the posterior approach had required surgical revision for bleeding on postoperative day 2. No temporary lesions were recorded. No early amputations were required, and no perioperative deaths occurred. The median length of stay was 3 days (IQR, 3-4 days). An expanded polytetrafluoroethylene graft was used in 92 cases (88%) and a Dacron graft in 12 cases (12%). An 8-mm graft was used in 64 cases (62%). The median follow-up was 34.6 months (IQR, 8.5-62.7 months). No related mortality occurred. Of the 104 PAAs, 19 had required reintervention, with primary and secondary patency of 78% and 88% at 3 years, respectively. The median interval to reintervention was 28.3 months. ConclusionsOSR of PAAs with prosthetic grafts is safe and feasible, with good mid-term results and satisfactory primary and secondary patency at 3 years.

A Unique Case of an Expanded Polytetrafluoroethylene Graft Rupture 14 Years after Abdominal Aortic Aneurysm Open Repair Managed with Placement of a Thoracic Endograft.

We report a unique case of expanded polytetrafluoroethylene (ePTFE) tube graft rupture that occurred 14 years after abdominal aortic aneurysm (AAA) repair. Endovascular repair with a thoracic endograft was performed. Postoperatively, an increase in the size of the existing hematoma with active extravasation occurred and was managed with iliolumbar artery embolization. Τo the best of our knowledge, rupture of ePTFE graft used for AAA repair has not been reported in the literature.

Omniflow II biosynthetic grafts versus expanded polytetrafluoroethylene grafts for infrainguinal bypass surgery. A single-center retrospective analysis.

The aim of this study is to evaluate the outcome of Omniflow II biosynthetic vascular grafts as compared to synthetic expanded polytetrafluoroethylene (ePTFE) grafts in infrainguinal bypass surgery. A single-center, retrospective, observational study was performed reviewing patients with critical limb ischemia who underwent infrainguinal bypass surgery between 2014 and 2018. Patients characteristics, graft characteristics, and treatment outcomes were collected. Patency rates were compared using Kaplan-Meier estimates. Sixty bypasses were performed in 57 patients. For above-knee surgery, six were Omniflow and 13 were synthetic. For below-knee surgery, 19 were Omniflow and 22 were synthetic. Patient characteristics between groups were similar. However, American Society of Anesthesiologists (ASA) classification scores were higher in the Omniflow group as compared to ePTFE (88% was ASA 3 or higher versus 60%; p = 0.018). Furthermore, wound, ischemia, and foot infection (WIfI) composite scores were higher in the Omniflow group (p = 0.0001). There was a trend toward more active infection at time of surgery in the Omniflow group (40 vs 22.9%, p = 0.15). At 1year, primary patency rates were 60.0% versus 46.9% for above-knee Omniflow versus ePTFE grafts, respectively (p = 0.72). Secondary patency rates were 80.0% versus 82.5% (p = 0.89), and limb salvage rates were 83.3% versus 100% (p = 0.14). For below-knee surgery, 1- and 2-year primary patency rates in Omniflow versus ePTFE grafts were 36.0% versus 41.8% (p = 0.60) and 36.0% versus 31.1% (p = 0.87). Secondary patency rates were 66.8% versus 75.2% at 1year (p = 0.53) and 58.8% versus 48.3% (p = 0.77) at 2years. Below-knee limb salvage rates for Omniflow versus ePTFE after 2years were 88.0% versus 68.3% (p = 0.28), respectively. Aneurysmal degeneration occurred in 2/25 (8%) in the Omniflow group and 0/35 (0%) in the ePTFE group. Bypass infections occurred in 2/25 (8%) in the Omniflow group and 0/35 (0%) in the ePTFE group (p = 0.09). Omniflow bypasses were more commonly implanted in patients with higher limb infection rate as confirmed with a higher adapted WIfI score. A trend toward a higher infection rate of Omniflow grafts was observed but not statistically significant. Graft infection rates were relatively low and treatable with antibiotics. No significant difference in graft performance was observed. The choice between the two studied grafts remains based on surgeon's preference.

Evaluation of heparin-bonded ePTFE grafts for forearm loop vascular access: Comparison between Gore® PROPATEN vascular graft and ACUSEAL vascular graft.

This retrospective study evaluates the clinical outcomes of two heparin-bonded expanded polytetrafluoroethylene grafts, PROPATEN and ACUSEAL (W. L. Gore & Associates, Flagstaff, AZ, USA), for forearm loop vascular access. We prospectively collected data on 60 patients who had undergone arteriovenous graft of the forearm loop type between January 2015 and December 2019. The primary endpoints were graft primary, assisted primary, and secondary patency rates. Secondary endpoints were time to first cannulation and postoperative complications. We enrolled 36 patients in the PROPATEN group (Group P) and 24 in the ACUSEAL group (Group A). All procedures were successful without any 30-day mortality. The median times to first cannulation were 16.5 days and 3 days in Groups P and A, respectively (p < 0.001). Mean follow-up periods were 13.4 ± 14.5 and 17.3 ± 9.3 months, respectively. Primary patency rates were 81% and 64%, respectively, at 6 months, and 60% and 40%, respectively, at 12 months (p = 0.008). Assisted primary patency rates were 96% and 83% at 6 months, 91% and 73% at 12 months, and 81% and 35% at 24 months (p = 0.044). Secondary patency rates were 96% and 81% at 12 months, and 87% and 62% at 24 months (p = 0.207). As a remote-period complication, disruption of the luminal layer of the graft was observed in two patients (4.2%) in Group A due to puncture and thrombectomy. Although the ACUSEAL graft offers the advantage of early cannulation, its primary and assisted primary patency outcomes were inferior to those of the PROPATEN graft. It is important for physicians to be aware of the different characteristics of each graft to select the best option for each patient.

Use of Heparin-Bonded Expanded Polytetrafluoroethylene Grafts for Renal Artery Reconstruction

BackgroundThe purpose of this study was to analyze our initial experience in renal artery reconstruction with heparin-bonded expanded polytetrafluoroethylene (ePTFE) grafts. MethodsThe authors retrospectively reviewed the data of consecutive patients who received open renal reconstruction with a heparin-bonded ePTFE graft at our institution between January 2014 and December 2019. ResultsA total of 22 renal reconstructions with a heparin-bonded ePTFE graft were performed in 17 consecutive patients. In all cases, renal reconstruction was a concomitant procedure during surgical or endovascular aortic procedures. Postoperative complications within 30 days were observed in 9 (53%) patients, including acute kidney injury (n = 6), pneumonia (n = 1), retrograde type B aortic dissection (n = 1), and lower limb ischemia (n = 1). The 30-day mortality rate was 0%. In a median follow-up period of 32 (19–39) months, all grafts were patent without re-intervention. Six patients with preoperative stage 2 chronic kidney disease progressed to stage 3 during follow-up. No patient required temporary or permanent hemodialysis. One patient died from intestinal ischemia at 23 months after surgery. ConclusionsThis study showed that the patency after open renal reconstruction with a heparin-bonded ePTFE graft was excellent, with acceptable renal outcomes, and demonstrates its safety as a concomitant procedure during an aortic procedure. Heparin-bonded ePTFE grafts are a feasible and effective choice for open renal reconstruction in contemporary practice.

Long Term Degeneration and Spontaneous Rupture of an Expanded Polytetrafluoroethylene Graft

A 70 year old female presented acutely with a suprapubic pulsating mass 35 years after a femorofemoral crossover bypass. (A) Computed tomography angiography showed a pseudoaneurysm in the middle of an expanded polytetrafluoroethylene prosthetic graft (manufacturer unknown). Intra-operatively, there was severe plastic deformation and graft calcification without infection. It could neither be cross clamped nor oversewn and so was explanted and a new femorofemoral reconstruction with an 8 mm knitted polyester tube graft (Flownit Bioseal, Jotec GmbH, Hechingen, Germany) was performed. It is likely that due to these long term changes it spontaneously ruptured as a hole was found in its middle (B). The post-operative course was uneventful.Image 1

Risk Factors for Mid-Term Liver Disease After the Fontan Procedure.

The Fontan procedure is a palliative surgery performed for patients with complex congenital heart disease who exhibit functional single ventricular physiology. Although clinical outcomes of the Fontan procedure have improved in recent years and most patients who undergo the procedure reach adulthood, Fontan-associated liver disease (FALD) is a noncardiovascular complication that has become increasingly common; its risk factors remain unknown.A total of 95 patients who underwent the Fontan procedure and who were followed up for at least three years at Gunma Children's Medical Center and Kitasato University Hospital between 1996 and 2015 were retrospectively enrolled in this study.The mean age of the patients at the time of Fontan procedure was 2.3 ± 1.4 years. Overall, 21 patients (23.1%) experienced FALD. All Fontan procedures were performed with extracardiac total cavopulmonary connection using 16-mm expanded polytetrafluoroethylene grafts. The presence of systemic right ventricle, requirement of pulmonary vasodilator, application of a non-fenestrated Fontan procedure, and absence of fenestration flow at the time of follow-up catheter examination were identified as predictors of FALD using univariate analysis. All these factors, except the requirement of pulmonary vasodilator, remained significant predictors of FALD in multivariate logistic regression analysis.Patients with a systemic right ventricle who undergo the Fontan procedure are at a high risk of FALD in the mid-term. Creating fenestration at the time of Fontan and maintaining the fenestration flow may reduce the mid-term risk of FALD.

Simultaneous Axillary–Carotid and Carotid–Axillary Bypass

We here report a case of a 52-year-old man who underwent simultaneous bypass grafting surgery on his carotid–axillary arteries bilaterally (axillary–carotid and carotid–axillary bypasses) after a failed endovascular treatment. This has rarely been reported. Imaging follow-up at 5 days showed bypass graft patency, and he developed no complications. At 1-month follow-up, the patient had no discomfort or recurrence of vertigo and ataxia and his blood pressure was steady and normal bilaterally. The results in this patient indicate that axillary–carotid and carotid–axillary bypasses using expanded polytetrafluoroethylene grafts are a safe and valuable techniques for revascularizing common carotid artery and subclavian artery occlusive diseases, achieving patency and freedom from stroke in the short term. Long-term outcomes are yet to be determined.

Recent Advances in Arteriovenous Access Creation for Hemodialysis: New Horizons in Dialysis Vascular Access.

Recent advances in technology show promise in providing greater vascular access options for hemodialysis patients. This review discusses novel methods for creating an anastomosis for arteriovenous (AV) fistulas and new materials for prosthetic AV grafts. Two technologies for endovascular arteriovenous fistula creation, the Ellipsys and WavelinQ endovascular systems, are discussed. When an AV fistula is not possible, an AV graft or devices to augment the AV fistula may be appropriate. New materials that have been developed that show promise as an alternative to the expanded polytetrafluoroethylene graft are discussed. Such potential conduits include bioengineered vessels and both allogenic or xenogenic biologic grafts. Devices designed to optimize blood flow to reduce maturation failure and improve AV fistula outcomes are explored.