Polytetrafluoroethylene Stent Graft Research Articles

Covered stent assisted coil embolization of large Buhler aneurysm in setting of chronic celiac trunk occlusion

BackgroundThe arc of Bühler (AOB) is a residual embryonal anastomosis between the celiac artery (CA) and the superior mesenteric artery (SMA). Although usually asymptomatic, it has clinical relevance when compensatory reverse flow between the SMA and the CA in response to celiac artery obstruction leads to aneurysm formation and bleeding. Endovascular coiling is the mainstay therapy because of the deep AOB retropancreatic location, which hinders open surgery.Case presentationWe herein report a case of a 2.8-cm AOB saccular aneurysm and LAM compression of celiac trunk in a 47-year-old man during rehabilitation following motorcycle trauma and vertebral surgery. The patient was considered unsuitable for surgery. Neither conventional coiling nor bare-metal stent and balloon-assisted techniques for coiling were suitable because of the wide necked saccular shape of AOB aneurysm interposed between the SMA and the floor of celiac trunk. To exclude the aneurysm from direct SMA inflow and permit safe and efficient coiling to rule out retrograde sac perfusion, a 9-mm polytetrafluoroethylene stent graft (Viabahn; Gore, Phoenix, AZ, USA) was positioned in the mesenteric artery, followed by antegrade periprosthetic high-density packed coiling of the aneurysm. The AOB remained excluded from mesenteric perfusion. The patient’s clinical condition and abdominal contrast-enhanced multislice computed tomographic findings were unremarkable at the 9-year follow-up.ConclusionThe 9 year long-term efficacy in our case raises the possibility that perigraft coiling following stent-graft deployment in the SMA may represent a valuable technical option for large Bühler aneurysms that are not amenable to stand-alone coiling.

EE437 Economic Value of Covered Expanded Polytetrafluoroethylene (EPTFE) Stent Grafts Compared to Percutaneous Balloon Angioplasty for Treating Thrombosed and Dysfunctional Arteriovenous Grafts in Hemodialysis Patients in Germany

Hemodialysis patients with an arteriovenous graft (AVG) implant can experience AVG stenosis and thrombosis which require further procedural revision to maintain an open circuit for hemodialysis. This analysis aims to establish the economic value of revising an AVG with a covered stent graft compared to percutaneous balloon angioplasty (PTA) using clinical and resource use data from the Gore REVISE Clinical Study along with cost data specific to German treatment setting.

Improving Bioactive Characteristics of Small Diameter Polytetrafluoroethylene Stent Grafts by Electrospinning: A Comparative Hemocompatibility Study.

Polytetrafluoroethylene (PTFE) is a commonly used biomaterial for the manufacturing of vascular grafts and several strategies, such as coatings, have been explored to improve the hemocompatibility of small-diameter prostheses. In this study, the hemocompatibility properties of novel stent grafts covered with electrospun PTFE (LimFlow Gen-1 and LimFlow Gen-2) were compared with uncoated and heparin-coated PTFE grafts (Gore Viabahn®) using fresh human blood in a Chandler closed-loop system. After 60 min of incubation, the blood samples were examined hematologically and activation of coagulation, platelets, and the complement system were analyzed. In addition, the adsorbed fibrinogen on the stent grafts was measured and the thrombogenicity was assessed by SEM. Significantly lower adsorption of fibrinogen was measured on the surface of heparin-coated Viabahn than on the surface of the uncoated Viabahn. Furthermore, LimFlow Gen-1 stent grafts showed lower fibrinogen adsorption than the uncoated Viabahn®, and the LimFlow Gen-2 stent grafts showed comparable fibrinogen adsorption as the heparin-coated Viabahn®. SEM analysis revealed no sign of thrombus formation on any of the stent surfaces. LimFlow Gen-2 stent grafts covered with electrospun PTFE exhibited bioactive characteristics and revealed improved hemocompatibility in terms of reduced adhesion of fibrinogen, activation of platelets, and coagulation (assessed by β-TG and TAT levels) similar to heparin-coated ePTFE prostheses. Thus, this study demonstrated improved hemocompatibility of electrospun PTFE. The next step is to conduct in vivo studies to confirm whether electrospinning-induced changes to the PTFE surface can reduce the risk of thrombus formation and provide clinical benefits.

EE443 Economic Value of Covered Expanded Polytetrafluoroethylene (eptfe) Stent Grafts Compared to Percutaneous Balloon Angioplasty for Treating Thrombosed and Dysfunctional Arteriovenous Grafts in Hemodialysis Patients in Spain

EE443 Economic Value of Covered Expanded Polytetrafluoroethylene (eptfe) Stent Grafts Compared to Percutaneous Balloon Angioplasty for Treating Thrombosed and Dysfunctional Arteriovenous Grafts in Hemodialysis Patients in Spain

Effect of expanded polytetrafluoroethylene thickness on paclitaxel release and edge stenosis in stent graft.

Stent grafts have been widely used to treat lower extremity arterial stenosis or occlusion. However, there are major issues with edge stenosis and loss of patency over time. Paclitaxel-coated stent grafts have been proven to be effective in preventing edge stenosis, but the insufficient amounts of paclitaxel released may limit the effectiveness of drug-eluting stent grafts. In this study, we examined whether paclitaxel-coated expanded polytetrafluoroethylene (ePTFE) stent graft thickness influences paclitaxel release properties and inhibits edge stenosis. Low-, medium-, and high-thickness paclitaxel-coated stent grafts were prepared by varying the thickness of inner and outer ePTFE layers. Surface morphologies of the stent grafts were analyzed using a scanning electron microscope. The stent grafts were then implanted in the iliac arteries of 20 healthy swine. Twelve pigs were used to assess edge stenosis, and digital subtraction angiography was performed at day 30 (n = 4), 90 (n = 4), and 180 (n = 4). Histological evaluation of the treated arteries was also performed. Eight pigs were used for pharmacokinetic analysis, and the treated arteries were obtained at day 1 (n = 2), 30 (n = 2), 90 (n = 2) and 180 (n = 2). Scanning electron microscopy confirmed that the mean pore size of the stent grafts decreased with increasing thickness. The results of angiographic and histological evaluation demonstrated that low-thickness ePTFE-stent grafts resulted in edge stenosis and apparent intimal hyperplasia at 180 days, whereas for medium-thickness ePTFE-stent grafts, no obvious edge stenosis and intimal hyperplasia was noted in the similar time period. The results of pharmacokinetic evaluation showed that at 180 days, the paclitaxel concentration of treated arteries of the medium group was 36 ± 53 ng/g, while concentrations in the low group was not detectable. Stent grafts with increased ePTFE thickness appear to allow for more delayed release of paclitaxel compared to low-thickness ePTFEs.

Experimental Analysis of In Situ Fenestration of Endovascular Stent-Grafts: Comparison between Needle and Laser Puncture

To evaluate the quality of in vitro fenestrations during in situ fenestration (ISF) and investigate the differences between needle and laser puncture in current stent-grafts. An in vitro study evaluated the damage created by needle ISF on stent-graft fabrics versus laser ISF. Fenestrations were made in 5 different commercially available stent-grafts, including polyester stent-grafts (Relay, Valiant and Hercules) and expanded polytetrafluoroethylene (ePTFE) stent-grafts (TAG and Ankura). Each stent-graft received fenestration by needle and laser separately, followed by gradual dilation (4 mm, 6 mm, 8 mm, and 10 mm sequentially) of noncompliant balloons. Quantitative and qualitative evaluations including fenestration diameter, area, shape and margins were conducted using light microscopy and scanning electron microscope. The primary fenestrations created by needle were slit-like with visible cut-off fibers in polyester stent-grafts and were almost circular with clear margins in ePTFE stent-grafts; those created by laser were squared or elliptical with ragged edges and burned fibers in all the stent-grafts. Fabric debris and toxic particles due to burning of the material were generated during laser-assisted fenestration. The Primary holes in polyester stent-grafts (Relay, Valiant and Hercules) by needle showed smaller area (0.05 mm2 vs. 0.22 mm2, 0.52 mm2 vs. 0.70 mm2 and 0.28 mm2 vs. 0.46 mm2; P < 0.01) and worse shape (0.93 vs. 2.46, 1.17 vs. 2.33 and 0.93 vs. 2.47; P < 0.01) than those by laser, while larger area (0.67 vs.0.43, 0.59 vs.0.45; P < 0.05), better shape (3.93 vs. 2.53, 3.90 vs. 2.93; P < 0.05) and better margin (3.83 vs. 2.47, 3.83 vs. 2.53; P < 0.05) in ePTFE stent-grafts (TAG and Ankrura). After gradual balloon dilation, the final holes showed no evident difference in maximal length, fenestration area, scores of shape and margin between the 2 ways of fenestration (P > 0.05). Ankura stent-graft showed the largest holes with best quality than the others. The primary fenestrations were different between needle and laser puncture, laser induced fabric debris and toxic particles release should be cautiously considered. The final fenestrations were similar after gradual balloon dilation.

S2384 Post-TIPS Hemolytic Anemia Due to Polytetrafluoroethylene Stent

INTRODUCTION: Transjugular intrahepatic portosystemic shunt (TIPS) procedures are performed to decrease the complications of portal hypertension in cirrhosis including salvage for variceal bleeds, medically refractory ascites, and hepatic hydrothorax. Although generally well-tolerated, encephalopathy and liver failure are major complications which can occur after the procedure. One of the lesser known complications of TIPS, however, is a transient hemolytic anemia, which we discuss here. It occurs in approximately 10% of cases. CASE DESCRIPTION/METHODS: A 65-year-old male with history of alcoholic cirrhosis decompensated by esophageal and gastric varices was referred to our facility after recent gastrointestinal hemorrhage to evaluate for a TIPS procedure. After being deemed a candidate, a 90 mm total length (70 mm covered / 20 mm uncovered) Viatorr (GORE, Flagstaff, AZ, USA) polytetrafluoroethylene (PFTE) stent-graft was successfully placed, and the portosystemic gradient decreased from 16 mmHg to 5 mmHg. Post-procedure, however, the patient developed worsening jaundice. Laboratory data demonstrated anemia with hemoglobin of 6.0 gm/dL, reticulocytosis with a reticulocyte index of 7.9%, hyperbilirubinemia with up-trending total bilirubin from 6.5 mg/dL to 18.9 mg/dL and an indirect bilirubin of 8.0 mg/dL, and findings consistent with hemolysis with an elevated LDH of 254 units/L, low haptoglobin of < 15 mg/dL, and a negative Coomb’s test. Peripheral smear showed anisocytosis, Burr cells, and target cells; no schistocytes were observed. This led to a diagnosis of non-immune hemolytic anemia. During the remainder of the patient’s hospital course, his hyperbilirubinemia slowly improved prior to discharge. DISCUSSION: Hemolytic anemia is one of the lesser known complications following TIPS. It was first described in the 1990s when bare metal stents (BMS) were commonly used. Literature refers to the hemolytic process with BMS as the “Naked Stent” syndrome due to injury of red blood cells after colliding with the exposed mesh of the stent. In order to improve stent patency and decrease complications, PFTE stents were introduced; however, hemolytic anemia may still occur as described in our case. The pathogenesis remains the same due to stent-related trauma to red blood cells as the covered PFTE stents have areas which remain exposed. With complete endotheliazation of the stent, the hemolytic anemia generally resolves without further intervention in 8–12 weeks.

Experimental Analysis of the Quality of Needle-Assisted Fenestration in Aortic Stent-Grafts and the Differences Between Gradual and Rapid Balloon Dilation

Purpose: To report the findings of an in vitro experiment to evaluate the quality of needle fenestrations dilated by different size balloons in various stent-grafts and to investigate the differences between gradual and rapid dilation. Materials and Methods: Fenestrations were made using an 18-G needle in 5 different polyester or expanded polytetrafluoroethylene (ePTFE) stent-grafts: Relay, Valiant, Hercules, TAG, and Ankura. Each stent-graft received 2 groups of fenestrations: one was followed by gradual sequential dilation (4-, 6-, 8-, and 10-mm balloons) and the other by rapid dilation (4- and 10-mm balloons). The pressure was increased to 10 atmospheres or until the balloon was fully inflated with no waist. Quantitative and qualitative evaluations, including fenestration diameter, area, shape, and margins were conducted using light microscopy and scanning electron microscopy. Results: Relay had the strongest resistance to dilation and Ankura the slightest. The maximum length and area of holes expanded as the balloon diameter increased. The fenestrations in polyester devices were mostly elliptical or slit-like, with limited tears but extensive fibers visible in the margin, while ePTFE stent-grafts showed larger fenestration areas with clearer margins. Ankura showed the best quality of fenestrations, which were always circular or square without fabric tears, while the holes in the TAG were square or elliptical but sometimes had a slit after large balloon dilation (≥6 mm). The Relay, Valiant, Hercules, and Ankura devices showed no difference in maximum diameter, fenestration area, or scores of shape and margin (p>0.05). Rapid dilation in the TAG increased the rate of uncontrolled fabric tear, resulting in a larger final diameter (12.90 vs 10.82 mm, p=0.047), smaller area (30.46 vs 41.09 mm2, p=0.028), worse shape (0.75 vs 1.20, p=0.268), and worse margin (0.40 vs 1.00, p=0.174). Though the decreased fenestration shape and margin scores did not reach statistical significance, the trend for decline was more obvious than with the other devices. Conclusion: Materials and structures of the stent-grafts determine the quality of fenestrations dilated by different size balloons. The use of sequential vs rapid balloon dilation is also crucial for fashioning high-quality fenestrations and should be selected judiciously.

Long-term patency and clinical outcome of the transjugular intrahepatic portosystemic shunt using the expanded polytetrafluoroethylene stent-graft.

BackgroundTransjugular intrahepatic portosystemic shunt (TIPS) creation is an established treatment option to management the complications of portal hypertension. Recent data on the long-term outcomes of TIPS are scarce.Materials and methodsIn this single-institution retrospective study, 495 patients underwent TIPS with the Fluency stent-grafts between December 2011 and June 2015 were evaluated. The cumulative rates of TIPS dysfunction, hepatic encephalopathy (HE), survival, and variceal rebleeding were determined using the Kaplan–Meier method. Cox regression analysis was used to assess the parameters on TIPS patency, occurrence of HE and all-cause mortality.ResultsTechnical success was 98.2%. TIPS-related complications occurred in 67 patients (13.5%) during the index hospital stay. TIPS creation resulted in an immediate decrease in mean portosystemic pressure gradient from 23.4 ± 7.1 mmHg to 7.6 ± 3.5 mmHg. The median follow-up period was 649 days. Primary TIPS patency rates were 93%, and 75.9% at 1 and 3 years, respectively. Previous splenectomy was associated with a higher risk of TPS dysfunction. The cumulative survival rates were 93.4% and 77.2% at 1 and 3 years, respectively. The 1- and 3-year probability of remaining free of variceal bleeding rates were 94.2% and 71.4%, respectively.ConclusionsThis retrospective single-center experience with TIPS using the Fluency stent-grafts demonstrates good long-term patency and favorable good clinical results. Previous splenectomy strongly predicts shunt dysfunction.

Long-term Results of Endovascular Treatment of TASC C and D Aortoiliac Occlusive Disease with Expanded Polytetrafluoroethylene Stent Graft

The aim of this study is to retrospectively analyze the early and long-term outcomes of endovascular treatment of Trans-Atlantic Inter-Society Consensus II class C and D (TASC II) aortoiliac occlusive disease with an expanded polytetrafluoroethylene-covered stent graft. Between January 2006 and November 2017, 61 patients (53 males, 8 females), with symptomatic aortoiliac stenotic and/or occlusive disease, were treated with VIABAHN (W.L. Gore and Associates, Flagstaff, Ariz) at 2 University medical centers. The morphology of the lesions was evaluated and classified by contrast-enhanced computed tomography angiography. Demographic data, operation details, and postoperative outcomes were collected. Follow-up data were analyzed by a life-table analysis (Kaplan-Meier test). Mean age of the patients was 64.89±10.77years (range 44-89). Thirty-seven patients (60.7%) presented with severe claudication (Rutherford 3), whereas 21 (34.4%) were in Rutherford class 4 and the remaining 3 patients (4.9%) suffered from necrotic lesions (Rutherford 5/6). Fifty-six patients were smokers (91.8%), 38 (62.3%) had hypertension, 23 (37.7%) had coronary artery disease, 30 (40.2%) had dyslipidemia, 18 (29.5%) had chronic obstructive pulmonary disease, 6 (9.5%) had renal insufficiency (serum creatinine>2.0mg/dL) and 24 (39.3%) had diabetes. Technical success was achieved in 59/61 patients (96.7%) with 16 patients (26.2%) requiring combined percutaneous brachial access to obtain iliac recanalization. Perioperative mortality was 1.6%, whereas postoperative major complications occurred in 2 patients (3.6%). The mean number of VIABAHN placed was 1.77/patient. Mean follow-up was 31.5months (range 1-108) and primary patency at 36 months was 94.9%. Two major amputations of the lower limbs occurred during the follow-up. Open surgery with the aortobifemoral bypass has been the gold standard treatment for complex aortoiliac occlusive disease although complications and mortality still remain significant issues. Our results suggest that endovascular therapy of TASC C and D iliac lesions using the VIABAHN stent graft is feasible, effective, and has good, long-term patency.

Percutaneous Transanastomotic Stent Graft Deployment to Salvage Dysfunctional Native Forearm Radiocephalic Fistulae: Feasibility and Primary Patency at 12 Months

PurposeTo evaluate feasibility and efficacy of transanastomotic self-expandable polytetrafluoroethylene stent graft placement for salvage of radiocephalic arteriovenous fistulae (RCAVFs). Materials and MethodsFrom 2008 to 2016, 26 patients (21 male; age, 38–80 y) with dysfunctional RCAVFs for juxtaanastomotic lesions that were unresponsive to angioplasty underwent transanastomotic stent graft placement. Stenotic and thrombotic lesions were included. All were deemed unsuitable for surgical revision. Patency rates were calculated per Kaplan–Meier method. A Cox analysis was used to identify influencing factors. ResultsThirty-two stent grafts (6 patients had 2 stents) were deployed. Anatomic and clinical success were achieved in all patients; no major complications occurred. Mechanical and/or pharmacologic thrombolysis was performed in 6 cases before stent graft deployment. During follow-up (median, 34.7 mo; range, 1.9–102.7 mo), 17 repeat interventions were required in 10 patients (43 procedures overall), for an endovascular intervention rate of 0.27 per year. At 3, 6, 12, and 24 months, primary patency (PP) rates were 96% ± 4 (95% CI, 75%–99%), 83% ± 7 (95% CI, 61%–93%), 78% ± 8 (95% CI, 55%–90%), and 69% ± 10 (95% CI, 46%–84%). The corresponding assisted PP rates were 96% ± 4 (95% CI, 76%–99%), 96% ± 4 (95% CI, 76%–99%), 92% ± 5 (95% CI, 71%–98%), and 82% ± 8 (95% CI, 60%–93%). Five AVFs were ultimately abandoned. Per Cox analysis, arterial diameter ≥ 4 mm was associated with better PP (P = .032). ConclusionsTransanastomotic stent graft placement for RCAVF salvage is feasible and safe, providing patency rates comparable with historical endovascular and surgical data. Its role should be evaluated in larger studies.

Long-term outcome of endovascular popliteal artery aneurysm repair

ObjectiveThe position of endovascular treatment in the algorithm of popliteal artery aneurysm (PAA) repair is still a matter of debate. Although several studies have described results similar to those of open surgery, follow-up of the endovascular group has been relatively short so far. The aim of this study was to describe the long-term outcome of endovascular repair of PAA with endografts. MethodsAll patients with a PAA treated with an expanded polytetrafluoroethylene stent graft between June 1998 and November 2014 in a tertiary referral center were prospectively gathered in a database and retrospectively analyzed. The primary end point of this study was primary patency. Secondary end points included primary assisted and secondary patency, survival of the patient, stent fractures, secondary interventions, and limb loss. ResultsA total of 75 PAAs were treated in 64 patients with a mean age of 68.1 ± 9.4 years. Unilateral PAA was present in 39 patients (61%) and bilateral PAAs in 25 patients (39%), of which 11 (17%) were treated bilaterally. Median follow-up was 68 months (range, 2-187 months). Primary patency at 1 year, 5 years, and 10 years was 84%, 60%, and 51%, respectively; primary assisted patency, 84%, 65%, and 57%; and secondary patency, 89%, 71%, and 60%. Stent fractures occurred in 28% of the cases (n = 21) in a median follow-up time of 47 months (range, 14-187 months). One-third of the fractures were associated with an occlusion that mainly presented with claudication, and only one was associated with acute ischemia. Reinterventions were performed in 12 cases (16%) during a median follow-up of 14 months (range, 1-47 months). The reintervention-free survival after 1 year, 5 years, and 10 years was 93%, 79%, and 79%, respectively. No major amputations were performed. The overall survival rate after 5 years and 10 years was 78% and 46%, respectively. ConclusionsEndovascular repair has established a definitive role in the treatment protocol for PAAs. It is associated with acceptable long-term patency rates. Stent fractures occurred in almost one-third of cases but never led to limb loss. Future developments should focus on the design of more dedicated and durable stents for this specific indication.

A Prospective, Randomized Study of an Expanded Polytetrafluoroethylene Stent Graft versus Balloon Angioplasty for In-Stent Restenosis in Arteriovenous Grafts and Fistulae: Two-Year Results of the RESCUE Study

PurposeTo assess the safety and efficacy of an expanded polytetrafluoroethylene stent graft versus balloon angioplasty for the treatment of in-stent restenosis in the venous outflow of hemodialysis access grafts and fistulae. Materials and MethodsTwo hundred seventy-five patients were randomized at 23 US sites to stent-graft placement or percutaneous transluminal angioplasty (PTA). Primary study endpoints were access circuit primary patency (ACPP) at 6 months and safety through 30 days; secondary endpoints were evaluated through 24 months. ResultsACPP at 6 months was significantly higher in the stent-graft group (18.6%) versus the PTA group (4.5%; P < .001), and freedom from safety events (30 days) was comparable (stent graft, 96.9%; PTA, 96.4%; P = .003 for noninferiority). The separation in ACPP survival curves remained through 12 months (stent graft, 6.2%; PTA, 1.5%). Treatment area primary patency (TAPP) was superior for the stent-graft group (66.4%) versus the PTA group (12.3%) at 6 months (P < .001), with a survivorship difference in favor of stent-graft placement maintained through 24 months (stent graft, 15.6%; PTA, 2.2%). ACPP and TAPP for the stent-graft group were better than those for the PTA group when compared within central and peripheral vein subgroups (P < .001). In central veins, TAPP was 13.6% in the stent-graft group versus 4.3% in the PTA group at 24 months (P < .001). ConclusionsStent-graft use provided better ACPP and TAPP than PTA when treating in-stent restenosis in patients receiving dialysis with arteriovenous grafts and fistulae.

Prospective, Randomized, Concurrently-Controlled Study of a Stent Graft versus Balloon Angioplasty for Treatment of Arteriovenous Access Graft Stenosis: 2-Year Results of the RENOVA Study

PurposeTo present final, 2-year data from randomized comparison of an expanded polytetrafluoroethylene stent graft (SG) and percutaneous transluminal angioplasty (PTA) for treatment of arteriovenous graft (AVG) anastomotic stenoses. Materials and MethodsA 28-site, prospective, controlled US study enrolled 270 patients with malfunctioning AVG anastomotic stenoses of ≥ 50%; 138 patients underwent SG placement, and 132 underwent PTA alone. Follow-up imaging and intervention were event-driven. ResultsThe study was completed by 191 patients (97 SG, 94 PTA). Five patients were lost to follow-up or withdrew; 74 patients died during the study (38 SG, 36 PTA). At 12 months, treatment area primary patency (TAPP) was SG 47.6% versus PTA 24.8% (P < .001), access circuit primary patency (ACPP) was SG 24% versus PTA 11% (P = .007), and index of patency function (IPF) was SG 5.2 months/intervention ± 4.1 versus PTA 4.4 months/intervention ± 3.5 (P = .009). At 24 months, TAPP was SG 26.9% versus PTA 13.5% (P < .001), ACPP was SG 9.5% versus PTA 5.5% (P = .01), and IPF was SG 7.1 months/intervention ± 7.0 versus PTA 5.3 months/intervention ± 5.2; estimated number of reinterventions before graft abandonment was 3.4 for SG patients versus 4.3 for PTA patients. There were no significant differences in adverse events (P > .05) except for restenosis requiring reintervention rates of 82.6% in PTA patients versus 63.0% in SG patients (P < .001). ConclusionsAt 2 years, SG use provided a sustained, greater than 2-fold advantage over PTA in treatment area and overall access patency. Time to subsequent intervention was longer in the SG group.

Clinical Outcome of Isolated Popliteal Artery Aneurysms Treated with a Heparin-bonded Stent Graft

The use of self-expanding stent grafts for treatment of popliteal artery aneurysms (PAA) is a matter of debate, although several studies have shown similar results compared with open surgery. In recent years, a new generation stent graft, with heparin-bonding technology, became available. The aim of this study is to present the results of endovascular PAA repair with heparin-bonded stent grafts. Data on all patients with PAA treated with a heparin-bonded polytetrafluoroethylene (ePTFE) stent graft between April 2009 and March 2014 were gathered in a database and retrospectively analyzed. Data were collected from four participating hospitals. Standard follow-up consisted of clinical assessment, and duplex ultrasound at 6 weeks, 6 months, 12 months, and annually thereafter. The primary endpoint of the study was primary patency. Secondary endpoints were primary-assisted and secondary patency and limb salvage rate. A total of 72 PAA was treated in 70 patients. Mean age was 71.2±8.5 years and 93% were male (n=65). The majority of PAA were asymptomatic (78%). Sixteen cases (22%) had a symptomatic PAA, of which seven (44%) presented with acute ischemia. Early postoperative complications occurred in two patients (3%). Median follow-up was 13 months (range 0-63 months). Primary patency rate at 1 year was 83% and after 3 years 69%; primary assisted patency rate was 87% at 1 year and 74% after 3 years. Secondary patency rate was 88% and 76% at 1 and 3 years, respectively. There were no amputations during follow-up. Endovascular treatment of PAA with heparin-bonded stent grafts is a safe treatment option with good early and mid-term patency rates comparable with open repair using the great saphenous vein.

Use of a hybrid polytetrafluoroethylene stent graft for iliofemoral bypass in the setting of femoral blow-out.

Revascularization in the setting of anastomotic “blow-out” in the groin is a technically demanding and morbid undertaking, often mandating transabdominal or retroperitoneal exposure of the iliac artery for proximal control or anastomosis, or both. The Gore Hybrid Vascular Graft (W. L. Gore and Associates Inc, Flagstaff, Ariz) is an expanded polytetrafluoroethylene graft with an external nitinol stent on one end designed for remote venous implantation for proximal axillary vein dialysis access outflow. We recently used this device to treat femoral anastomotic disruptions in two postoperative patients.

Grade III Coronary Artery Perforation Following PCI and Unusual Stent Graft Delivery System

ABSTRACT Coronary perforations are rare but vicious complications of PCI procedures. Ellis type III coronary artery perforation represents the most severe form and demands an urgent solution. It is often necessary to perform pericardiocentesis and utilizise multiple interventional techniques to seal the perforation. Polytetrafluoroethylene (PTFE)-covered stent implantation has become one of the most frequently used percutaneous solutions, but disadvantages of this intervention are its high profile and low device flexibility. In our case, we attempted to improve the deliverability of the PTFE stent graft alone by mounting it on a bare metal stent used as a stent graft carrier.

Outcome of Thrombolysis and Thrombectomy for Thrombosed Endografts Inserted in the Superficial Femoral Artery for Occlusive Disease

To evaluate the efficacy and outcome of thrombolysis and thrombectomy for thrombosed polytetrafluoroethylene stent-grafts inserted in the superficial femoral artery (SFA) for occlusive disease. A retrospective review was conducted of 79 consecutive patients with a thrombosed SFA endograft between November 2001 and December 2011. Of these, 46 (58%) were treated with thrombolysis (n=40, 87%) or thrombectomy (n=6, 13%) and form the study group (33 men; median age 66.8 years, range 30-80). Median time from stent-graft insertion to thrombosis was 3 months (range 0-53). Thrombolysis was successful in 38 (95%) patients over a mean 24 hours (range 3-48); one patient had failed lysis and another died during lytic treatment. Thrombectomy was successful in all 6 patients. Thrombosis without a causal lesion was significantly more common in occlusions that presented <30 days after insertion (p=0.01). Over a median follow-up of 14 months (range 1-69), reinterventions were performed for restenosis in 12 patients and reocclusion in 14 patients, all within 18 months after thrombolytic treatment. More than a third of patients (16/45) had definitive failures (2/6 from the thrombectomy group); 4 were treated conservatively (no/minor symptoms) and 12 had bypass grafts. Three (7%) patients eventually required a major amputation. The primary, assisted primary, and secondary patency rates of thrombolysis at 6 months were 56%, 56%, and 68%, respectively. Secondary patency for the entire cohort was 58% at 1 year. Thrombolysis and thrombectomy of thrombosed endografts in the SFA is effective and safe. Patency rates after treatment are moderate, but prolonged secondary patency can be achieved.

Invited commentary

The strengths of this multicenter prospective trial comparing bare nitinol stents to polytetrafluoroethylene stent grafts for TransAtlantic Inter-Society Consensus 1 C and D superficial femoral artery lesions include an uncommon effort to standardize methodology and an uncommon glimpse at 3-year outcomes. The investigators are to be commended for attempting to drive a guidepost into the riverbed and refusing to go with the flow, simply assuming that any decent study will be outdated by intercurrent innovations such as drug-eluting stents and heparin-bonded stent grafts. The study tests the reasonable hypothesis that covered stents would eliminate in-stent restenosis, a chief cause of nitinol stent failure. Though the patency comparisons at 3 years suffer from some attrition of patients with cautionary wobble in the Kaplan-Meier curves, there was no apparent patency advantage to stent grafts. The reader remains intrigued by the lack of details regarding the ultrasound and angiographic lesions responsible for device failure, which given the surveillance protocol and high rate of reintervention, must have been available to allow distinction between intimal hyperplasia at the stent margins or within the stents and progression of disease in untreated adjacent arterial segments. Among patients followed for 36 months, the stent fracture rate was 50% for nitinol stents and only 2% for stent grafts. Acknowledging that the impact of stent fracture is controversial, if one assumes a negative impact of fracture on nitinol stent patency and a positive impact of less in-stent restenosis on stent graft patency, we might have expected an unequivocal patency advantage for stent grafts rather than the somewhat disappointing equivalency between the two groups. If indeed nitinol stents and stent grafts do have similar efficacy, device cost would assume more importance in the current penny-pinching era. Comparison of trial results with surgical bypass is invalidated by randomization of patients only after lesions had been crossed by a guidewire. Nonetheless, optimal results at 3 years were attained only after one or more reinterventions in 40% of patients, a much higher rate than might be expected in a series of superficial femoral artery bypasses. Again, costs need consideration. The study employed somewhat confusing patency definitions unfamiliar to most surgeons accustomed to tracking bypass grafts. Development of standards for reporting has been one of the signal contributions to vascular surgery over the years, and we must extend this effort to the endovascular arena, including our colleagues in related subspecialties. Only by adopting uniform research methodology can we build fruitfully on earnest efforts such as those of the VIBRANT trial team. Three-year results of the VIBRANT trial of VIABAHN endoprosthesis versus bare nitinol stent implantation for complex superficial femoral artery occlusive diseaseJournal of Vascular SurgeryVol. 58Issue 2PreviewThe predominant mode of bare nitinol stent failure is diffuse in-stent restenosis, and failure rates correlate to the length and complexity of the treated lesion. Addition of an expanded polytetrafluoroethylene lining to a nitinol stent frame, as found in the VIABAHN endoprosthesis, mitigates the ingrowth of intimal hyperplasia. We compared the long-term outcomes of complex superficial femoral artery disease intervention using the VIABAHN endoprosthesis to those obtained with bare nitinol stent implantation. Full-Text PDF Open Archive

Percutaneous Balloon-Expandable Stent Graft Repair of a Ruptured Iliac Aneurysm

Elective stent graft repair of iliac aneurysm is successful and safe. There are, however, few published data on stent grafting unstable patients with acute iliac aneurysm rupture. Iliac diameter mismatch can also present a challenge to emergency endovascular treatment. We report the treatment of an unstable patient with iliac aneurysm rupture and diameter mismatch using a percutaneous balloon-expandable polytetrafluoroethylene (PTFE) stent graft. Outcomes were satisfactory up to 12-month follow-up. Treatment of iliac aneurysm rupture using a balloon-expandable stent graft can be successful in selected patients. A percutaneous approach and targeted stent graft postdilatation enable prompt repair in the presence of diameter mismatch, facilitating emergency therapy.