Polytetrafluoroethylene Grafts Research Articles

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.

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.

Retrograde approach for innominate artery stenting using flow reversal for neuroprotection in Re-operative carotid field

A case of a 74 year old female with a prior history of right carotid endarterectomy (CEA) followed by carotid interposition bypass with polytetrafluoroethylene (PTFE) graft several years later due to restenosis. At 1 year follow up, she was found to have low velocities in the bypass and reversal of flow in her right vertebral artery indicating proximal stenosis. A computed tomography angiography (CTA) and magnetic resonance angiography (MRA) were obtained showing high grade occlusive lesion at her innominate artery. After an unsuccessful attempt at transfemoral endovascular intervention, the patient was brought back for a transcarotid retrograde approach utilizing ENROUTE ® Neuroprotection System with flow reversal for embolic protection. The lesions was crossed successfully in this approach and a balloon mounted covered stent was deployed using Gore ® VBX stent. There was significant amount of debris in the filter which would have embolized without neuroprotection. Patient was discharged on postoperative day 1 with no neurological deficits. In conclusion, this case highlights a successful use of ENROUTE ® Neuroprotection System flow reversal for retrograde transcarotid approach to treat difficult innominate lesions with satisfactory embolic protection.

Compari̇son of PTFE sutures with polypropylene sutures in suprapopliteal femoropopliteal bypass with PTFE grafts

Aim: Infrainguinal bypass surgery stands as the predominant open surgical procedure for lower limb revascularization and is reserved for cases of intermittent claudication (IC) that have proven unresponsive to maximal medical management. Polypropylene monofilament sutures have been widely used for peripheral vascular surgery operations. Aim of this study is comparing this new type of suture with propylene sutures. Material and Methods: Between January 2022 and December 2022, two cohorts who underwent suprapopliteal femoropopliteal bypass surgery, each comprising 15 patients were included in the study. In Group I (polytetrafluoroethylene (PTFE) Group), PTFE served as the suture material, whereas in Group 2 (Non PTFE Group), polypropylene sutures were employed. All preoperative demographics, perioperative and postoperative data were collected carefully. Results: All patients underwent surgical interventions due to either rest pain or ischemic ulcers. Among the 30 patients, 11 fell into Fontaine class 4, while 19 were categorized as Fontaine class 3. Out of the 30 patients, 18 received cilostazol treatment. The mean age of the patient cohort was 66.97±7.4 years, with a mean body mass index of 29.03±6.2. When we compared the two groups, no statistically significant difference was found between groups according to demographic data. In the evaluation of intraoperative data, the mean operation time was 88.7±9.37 minutes, and the mean hemostasis time was 5.8±2.8 minutes. Group I (PTFE group) exhibited significantly lower hemostasis time and drainage levels on the first and second postoperative days (p<0.0001, p=0.03, and p=0.017, respectively). The use of absorbable hemostats were significantly less in PTFE suture group. Conclusion: The selection of sutures significantly influences the achievement of soft tissue approximation, reduced inflammation, suture hole leakage and capsule formation.

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.

Management of lower extremity vascular injuries in pediatric trauma patients: 20-year experience at a level 1 trauma center

IntroductionPediatric lower extremity vascular injuries (LEVI) are rare but can result in significant morbidity. We aimed to describe our experience with these injuries, including associated injury patterns, diagnostic and therapeutic...

Our Surgical Results in Popliteal and Infrapopliteal Artery Injuries: 21 Cases without Amputation.

Popliteal and infrapopliteal artery injuries have significant morbidity and mortality rates, especially in terms of amputation. In our study, we aimed to evaluate patients who operated due to popliteal and infrapopliteal vascular injuries in our clinic. Patients and Methods. Between 2016 and 2023; 21 patients who were operated in our clinic due to popliteal and infrapopliteal artery injuries were retrospectively evaluated. 2 of the patients were female (9.5%) and 19 were male (90.5%). Age ranges were 21-78. The causes of injury were gunshot wounds in 9 patients (42.86%), blunt trauma in 7 patients (33.33%), and sharp object injuries in 5 patients (23.80%). Reversed saphenous vein interposition in 7 patients (33.33%), primary repair in 6 patients (28.57%), 6 mm polytetrafluoroethylene graft (PTFE) interposition in 3 patients (14.28%), end-to-end anastomosis in 2 patients (9.52%), saphenous-PTFE composite graft interposition in 2 patients (9.52%), and embolectomy in 1 patient (4.76%) were performed. Arterial ligation was not performed. Simultaneous orthopedic intervention was performed in 8 patients. Fasciotomy was performed in 3 patients. Venous repair was performed in 5 patients with venous injuries. Vein ligation was not performed. Mortality was observed postoperatively in 1 patient. No patient developed amputation. Foot drop developed with nerve damage in 2 patients. Mortality and morbidity rates may increase in popliteal and infrapopliteal artery injuries in cases of hemodynamic disorder, simultaneous bone fracture, multivessel injury, and nerve transection. These rates can be reduced by appropriate surgical repair and ensuring hemodynamic stability.

Efficacy and safety of Apixaban for the prevention of thrombosis in arteriovenous grafts.

This research aims to fill a vital gap in existing studies by evaluating the efficacy and safety of Apixaban, a direct oral anticoagulant, in the prevention of arteriovenous graft (AVG) thrombosis, thereby offering substantial insights into alternative anticoagulant options for hemodialysis patients. Conducted as a multi-center, randomized, double-blind, placebo-controlled trial, this study involved end-stage renal disease (ESRD) patients who had recently received polytetrafluoroethylene grafts. Participants were assigned to receive either Apixaban at a dose of 2.5 mg twice daily or a placebo. The primary outcome measure was the occurrence of graft thrombosis, while secondary outcomes focused on the incidence and severity of bleeding. Analytical methods included Kaplan-Meier estimates, Cox proportional hazards models, and conventional statistical tests. With 96 patients enrolled, the study found that Apixaban significantly reduced the incidence of AVG thrombosis compared to placebo (16.7% vs. 62.5%, P < 0.0001). Notably, this reduction in thrombosis incidence was not accompanied by an increase in bleeding events, thus affirming the safety profile of Apixaban as established in prior research. Apixaban is identified as an efficacious alternative to traditional anticoagulants in the prevention of AVG thrombosis among hemodialysis patients, representing a notable advancement in the care of individuals with ESRD. The results of this study support further investigations into the optimal dosing strategies specifically tailored for this patient demographic.

Interaction of material- and structural elasticity – an approach towards a physiological compliance in small-caliber vascular grafts

Research purpose: The low patency rate (less than 50% at a 5-years follow-up) of commercial vascular grafts is strongly associated with compliance mismatch between graft und native artery. To address this deficit, we investigated the influence of the material and structural elasticity on the compliance behavior of small caliber vascular graft gaining for a stress-strain behavior adapted to the native vessel. Material &amp; Methods: By combining different thermoplastic polycarbonate urethanes (TPU) fibers with different elasticity and non-elastic polyvinylidene fluoride (PVDF) fibers in different warp knitted tubular textile structures, we incorporate material and structural elasticity in a vascular graft (I.D. &lt; 6 mm). The evaluation of the tubular fabrics is performed by determining the compliance properties in a mean pressure range between 20 and 120 mmHg by tensile testing. Results: We identified the draw ration of the TPU fiber production, the stitch course density of the fabric and the thread tension of the TPU yarn during the warp knitting process as statistically highly significant effects ( p &lt; .005) on the compliance. With an adapted setting of those parameters, we were able to improve the compliance of the textile vascular grafts over the entire physiological pressure range (20–120 mmHg) by 400–630 % compared to current clinical ePTFE (expanded polytetrafluoroethylene) grafts towards native vessels. Conclusion: By combining material and structural elasticity in a warp knitted textile structure, we were able to biomimic the compliance towards physiological properties. Our approach can be seen as blueprint to adapt elasticity properties in other implant applications.

Vascular Access Blood Purification Treatments in Chronic Renal Failure: Impact on Quality of Life

Objective: To observe the effects of blood purification treatment and assess the prognostic impact of different vascular pathways on patients with chronic renal failure (CRF). Methods: A retrospective analysis of clinical data was conducted on 68 CRF cases, categorizing them based on their choice of blood purification vascular access. Group A received an autologous arteriovenous fistula, Group B received an internal jugular vein tunneled polyester sleeve catheter, and Group C received a polytetrafluoroethylene graft vascular fistula. Clinically relevant observation indicators, complication rates, and quality of life scores among the three groups were compared. Results: No significant differences were found between the three groups regarding observed values of clinically relevant indicators and quality of life scores (P &gt; 0.05). When comparing thromboembolism rates Group A had the highest rate, followed by Group C and Group B; for infection rate comparison, Group C had the highest rate, followed by Group B and Group A (P &lt; 0.05). Conclusion: In comparison with the other two vascular access methods, although autologous arteriovenous fistula poses a higher risk of thromboembolism, it exhibits a lower infection rate. Therefore, it is recommended as the preferred vascular access form for blood purification in patients with CRF. If this approach is unavailable, careful consideration should be given. The use of an internal jugular vein with a tunneled polyester sleeve catheter is suggested to better ensure the effectiveness and safety of the patient’s treatment.

Systematic review of risk factors and outcomes of post-implantation syndrome following endovascular aortic repair

ObjectivePost implantation syndrome (PIS) is an early systemic inflammatory response following endovascular aortic repair (EVAR). The response is variable in patients and the clinical significance of PIS upon outcomes is unknown. This study aims to evaluate the incidence, risk factors, and prognostic implication of PIS. MethodsSystematic literature review and analysis was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Cochrane guidelines of PubMed, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials. Eligible English-language studies regarding PIS after infrarenal EVAR were included, after removing duplicates. ResultsAfter screening, 31 studies were included. A total of 2847 patients were reviewed, with mean age of 70.7 years, of which 2012 (90.4%) were male, with a pooled mean follow-up of 26.1 months. PIS was reported in 25.3% of cases, with mean aneurysm diameter of 56.4 cm. Polytetrafluoroethylene (PTFE) grafts were utilized in 794 patients (27.9%) with polyester in 1839 (64.6%). White blood cell count, C-reactive protein, interleukin (IL)-6, IL-8, and IL-10 levels were all significantly elevated postoperatively. Thirty-day outcomes included type I endoleak rate of 0.8%, type II endoleak rate of 1.7%, reintervention rate of 0.35%, and mortality rate of 0.25%. Subgroup pooled analysis of patients with PIS (n = 309) vs No-PIS (n = 691) revealed that polyester (n = 642), rather than PTFE (n = 234) grafts, were associated with a higher rate of PIS (94.8% vs 3.7%; P = .0001), White blood cell count was higher in the PIS group both preoperatively (7.61 vs 6.76 × 109/L; P = .04) and postoperatively (15.0 vs 9.8 × 109/L; P = .0007) and IL-6 levels were higher in the PIS group postoperatively (98.6 vs 25.2 pg/mL; P = .02). Aneurysm diameter and amount of chronic or new thrombus within the aneurysm sac was not identified as a risk factor for PIS. Pooled outcomes of patients with PIS vs No-PIS demonstrated a significantly higher rate of 30-day mortality (0.6% vs 0%; P = .03) and major adverse cardiac events (5.8% vs 0.43%; P < .0001) without any differences seen in reintervention or 30-day type I or type II endoleaks. ConclusionsThis systematic review suggests that polyester grafts are strongly associated with PIS compared with PTFE. Interestingly, this report is suggestive of an association between 30-day mortality and major adverse cardiac events and PIS. Given these clinical sequelae, consideration for use of PTFE over polyester grafts to reduce the incidence of PIS may be a simple step to improve overall outcome. Further, exploration of the relationship between inflammatory mediators associated with PIS and mortality and cardiac complications may engender deeper understanding of risks, leading to eventual mitigation of harm for patients experiencing PIS.

Axilofemoral bypass in aortoiliac diseases: a case report

Introduction: In patients presenting with severe comorbid conditions and infra-renal aortic occlusion, an extra-anatomic bypass stands as one of the viable revascularization options for limb preservation. Axillofemoral bypass offers a valuable alternative in cases involving hostile abdominal environments or infectious aortic aneurysms. To our knowledge, this is the first report from Indonesia of a case of Aortoiliac Occlusive Disease (AIOD). This case report presents a 39-year-old female patient with complaints of left leg pain persisting for the past seven months. Case Description: A 39-year-old female patient sought care at our hospital, reporting left leg pain persisting for the past seven months. The pain worsened during physical activity and subsided during rest. She had a history of hypertension for the last eight years but no diabetes or smoking history. The previous hospital had diagnosed her with peripheral arterial disease, prescribing cilostazol and rivaroxaban, which provided only temporary relief. A computed tomography (CT) angiogram revealed occlusion of the abdominal aorta at the level of L2, extending to the left common iliac and right iliac arteries. We elected to perform an axilla-femoral bypass using a polytetrafluoroethylene (PTFE) graft, which yielded satisfactory results. The patient's progress was monitored for three months postoperatively. This report details the case of a female patient with aortoiliac occlusive disease. Given the absence of insurance coverage for endovascular treatment at our facility, we opted for an axilla-femoral bypass using a PTFE graft, which produced satisfactory outcomes during a three-month follow-up period. Conclusion: The axillofemoral bypass procedure is fairly safe and easy, especially in patients with a high risk of direct aortofemoral bypass and difficult anatomy. The number of collateral vessels in our patients based on CT scans and endovascular procedures that have not been supported by insurance in our hospital makes us choose the axillofemoral bypass option is the action we decided.

Hybrid stage 1 palliation with simultaneous off-pump ventricular assist device placement in neonates with high-risk single ventricle anatomy: Initial experience

BackgroundInfants with single ventricle heart disease and severe atrioventricular valve regurgitation have poor outcomes following conventional staged palliation. As such, ventricular assist device (VAD) placement along with hybrid stage 1 palliation has been proposed as a bridge to heart transplant. We present a novel surgical technique for VAD implantation concurrent with hybrid stage 1 that avoids cardiopulmonary bypass. MethodsWe performed a retrospective review of our institutional experience with this novel surgical technique. ResultsThree patients (weight, 2.7-3.5 kg; age, 3 to 5 days) underwent hybrid stage 1 with VAD placement, consisting of bilateral 3.5-mm expandable polytetrafluoroethylene (PTFE) pulmonary artery bands, a ductal stent, a 6-mm Berlin Heart outflow cannula onto the main pulmonary trunk with a 10-mm graft, a 6-mm Berlin Heart outflow cannula onto the right atrium, and a 10-mL Berlin Heart pump. In patients with severe aortic arch hypoplasia or coarctation, a 4-mm PTFE graft was sewn from the VAD outflow graft to the innominate artery to protect coronary and cerebral perfusion. Procedures were performed off bypass with minimal blood product use. Patients were extubated on postoperative days 2, 2, and 5. There were no procedural complications. All patients were transferred out of the intensive care unit and demonstrated appropriate weight gain. Anticoagulation strategy was bivalirudin and antiplatelet therapy. The patients underwent transplantation after 149 days, 157 days, and 288 days of support. ConclusionsOff-pump single ventricle VAD placement is technically feasible and can be done at the time of hybrid stage 1 palliation with minimal operative morbidity as a bridge to transplant.

Anticoagulation after pancreatic surgery with venous resection (TIGRESS): What should we do? Results from an international survey.

Patients who undergo pancreatic surgery with venous resection have high rates of morbidity/mortality. Also, they are high-risk for postoperative venous thromboembolism. Whether this group should be routinely anticoagulated is unknown. This study aimed to establish current anticoagulation practices. A survey (https://form.jotform.com/220242489107048) was sent out to pancreatic surgeons. Questions covered center volume, venous resection/reconstruction techniques and anticoagulation policies. Sixty-five centers from 17 countries responded. Following a "side-bite" venous resection with a patch repair, 40% used an autologous vein patch, 27% used peritoneum, and 27% used a bovine patch. After formally resecting a segment of vein, 17% of centers used an interposition graft (IG). Left renal vein (41%) and polytetrafluoroethylene (73%) grafts were the most commonly used autologous and prosthetic IGs, respectively. Following a prosthetic IG, an autologous IG, and a "side-bite" resection, 59%, 28%, and 19% of centers provided therapeutic anticoagulation, respectively (66% used low molecular-weight heparin). The duration of therapy provided varied from inpatient stay only (14%) to six months (32%). Our global survey indicates that anticoagulation practices are highly variable. Centers do not agree on when to anticoagulate, how to anticoagulate, or the duration of therapy. A robust trial is required to provide clarity.

Efficacy of boric acid used to treat experimental vascular graft infection by methicillin-resistant Staphylococcus aureus.

We aimed to investigate the efficacy of local boric acid (BA) and teicoplanin in prosthetic vascular graft infection (PVGI) caused by methicillin-resistant Staphylococcus aureus (MRSA) in a rat model. Fourty rats were divided into five groups. Group 1 received no treatments (control group); group 2 was uncontaminated polytetrafluoroethylene (PTFE) graft group; group 3 was untreated and the PTFE graft was contaminated with 2×107 CFU/mL MRSA; group 4 received local BA (8 mg/kg) and was contaminated with with 2×107 CFU/mL MRSA; group 5 received local BA (8 mg/kg) and intraperitoneal teikoplanin (10 mg/kg), and was contaminated with 2×107 CFU/mL MRSA; On the 3rd day, grafts and serums were removed for microbiological, histological and serological tests. The amounts of culture growth in groups 4 and 5 were significantly lower compared to group 3 (p < 0.001). TNF-α was significantly higher in Group 3 than the other groups (p = 0.001). There was no significant difference between the groups in serum IL-1 levels (p = 0.138). Monocyte chemotactic protein-1 (MCP-1) was not significantly different between groups 3, 4, and 5, but it was significantly higher than groups 1 and 2 (p < 0.001). The severity of inflammation was significantly higher in group 3 than the other groups, and fibroblastic proliferation, granulation tissue and collagen synthesis were significantly lower (p < 0.05). Our study showed that local BA and combined teicoplanin treatment is effective in preventing PVGI.

Use of Polytetrafluoroethylene Graft in Reconstruction of Middle Hepatic Vein and Right Inferior Hepatic Vein in Liver Transplantation and Rate of Non-Thrombosis of the Vein Our Three-Year Results

Amaç: Canlı Vericili Karaciğer Nakli (CVKN)’nde, modifiye sağ lob takılan hastalarda kullanılan Polytetrafluoroethylene (PTFE) greftlerin zamana göre açık kalma oranları değerlendirilmiştir. Ayrıca açık kalma oranını etkileyen faktörler, erken tıkanma sonrası gelişebilecek sorunlar ve olası greft ilişkili komplikasyonlar incelenmiştir. Materyal ve Metod: 2013-15 yıllarında ameliyat edilen, yaşları 17-74 arasında değişen 168 hasta çalışmaya dahil edildi. Postoperatif takiplerde çekilen Multislice Bilgisayarlı Tomografi (MSBT)’lerin venöz fazları retrospektif olarak incelendi. Hastalara kullanılan PTFE greftlerin tıkanma zamanları ve bu greftlerin drene ettiği segmentteki konjesyon durumu değerlendirildi. Greft ilişkili komplikasyonlar, Greft Alıcı Ağırlık Oranı (GAAO) değerleri ve postoperatif 1 aylık laboratuar bulguları da çalışmaya dahil edildi. Bulgular: Kullanılan PTFE greft açık kalma oranlarının, kriyopresipiye greft çalışmalarıyla kıyaslandığında, daha düşük olduğu görüldü. Greft lokalizasyonuyla açık kalma süreleri arasında anlamlı farklılık bulunmadı. Hastaların boy, kilo, BMI, karaciğer greft ağırlığı (KGA) ve greft alıcı ağırlık oranı (GAAO) ile ilk konjesyon, ilk tıkanma ve tüm venlerin tıkandığı zaman arasında anlamlı korelasyon bulunmadı. GAAO değerleri ile takiplerde tromboze olan greftlerin açık kalma zamanları arasında korelasyon tespit edildi. Kullanılan PTFE greft çapı ile açık kalma süresi arasında anlamlı ilişki bulunmadı. Transplantasyon nedenlerine göre açık kalma durumuna da bakıldı ancak anlamlı bir fark bulunmadı. Sonuç: PTFE greftler erken dönem açık kalma oranlarının yüksek olması nedeniyle, kriyopresipiye greftlerin bulunmadığı şartlarda ancak mevcut komplikasyon potansiyelleri akılda tutularak rekonstrüksiyon amaçlı olarak kullanılabilir.

SP2.8 AnTIcoaGulation afteR pancreatic surgery with vEnouS reSection (TIGRESS): what should we do? Results from an international survey

Abstract Aims Patients who undergo pancreatic surgery with venous resection/reconstruction (PSVRR) have high rates of morbidity/mortality and are at risk of postoperative venous thromboembolism (VTE). It is unknown if this group should be routinely anticoagulated. We developed a survey to establish current anticoagulation practices among pancreatic surgeons. Methods A JotForm.com survey was sent to members of various hepatopancreatobiliary societies. Questions covered: centre volume, venous resection/reconstruction techniques, and anticoagulation policies. Results Sixty-five centres from 17 seventeen countries responded. Following a “side-bite” venous resection and patch repair, 40% use an autologous vein patch, 27% use peritoneum and 27% use a bovine patch. When formally resecting a segment of vein, 17% of centres use an interposition graft (IG). Left renal vein (41%) and polytetrafluoroethylene (PTFE, 73%) grafts are the most commonly used autologous and prosthetic IGs, respectively. Following a prosthetic IG, an autologous IG, and a “side-bite” resection with patch repair, 59%, 28%, and 19% of centres provide therapeutic anticoagulation (TAG), respectively. Among the units that provide TAG, most (66%) use low molecular weight heparin. The duration of therapy provided varies from inpatient stay only (14%) to six months (32%). Conclusions Our global survey indicates that anticoagulation practices following PSVRR are highly variable. The centres do not agree on when or how to anticoagulate, or the duration of therapy. A robust trial is required to provide clarity on these issues.

Complications of e-PTFE Grafts in LDLT; Evaluation of Case Series

The expanded polytetrafluoroethylene (ePTFE) grafts are used to drain anterior sector veins during the living donor liver transplantation procedure. We aimed to analyze the potentially life-threatening complications, such as the infection and migration of ePTFE grafts. A total of 1264 liver transplantations (LTs) were performed for 1097 adult and 167 pediatric liver failure cases. In total, 1169 living and 95 cadaveric liver transplantation procedures were performed between 2011 and 2021. Right liver transplantation was performed in 1016 cases, including 1002 living donors and 14 cadaveric split right livers. Cadaveric LT was performed in 81 cases. For 1002 right living liver grafts, 905 vascular grafts were used during the backtable for anterior sector outflow venoplasty. The most commonly drained segments were 5 and 8 (472 cases); there were isolated (5 or 8) and multiple drained segments. Vascular graft migration was described in 7 of 905 (0.77%) patients. Although complication rates regarding ePTFE grafts are low, there are serious life-threatening causes of morbidity and mortality. We recommend cushioning the vascular graft with the omentum, which is effective in preventing graft migration.

A bio-instructive parylene-based conformal coating suppresses thrombosis and intimal hyperplasia of implantable vascular devices

Implantable vascular devices are widely used in clinical treatments for various vascular diseases. However, current approved clinical implantable vascular devices generally have high failure rates primarily due to their surface lacking inherent functional endothelium. Here, inspired by the pathological mechanisms of vascular device failure and physiological functions of native endothelium, we developed a new generation of bioactive parylene (poly(p-xylylene))-based conformal coating to address these challenges of the vascular devices. This coating used a polyethylene glycol (PEG) linker to introduce an endothelial progenitor cell (EPC) specific binding ligand LXW7 (cGRGDdvc) onto the vascular devices for preventing platelet adhesion and selectively capturing endogenous EPCs. Also, we confirmed the long-term stability and function of this coating in human serum. Using two vascular disease-related large animal models, a porcine carotid artery interposition model and a porcine carotid artery-jugular vein arteriovenous graft model, we demonstrated that this coating enabled rapid generation of self-renewable “living” endothelium on the blood contacting surface of the expanded polytetrafluoroethylene (ePTFE) grafts after implantation. We expect this easy-to-apply conformal coating will present a promising avenue to engineer surface properties of “off-the-shelf” implantable vascular devices for long-lasting performance in the clinical settings.