Hybrid Vascular Graft Research Articles

Over-the-balloon placement of the Gore Hybrid Vascular Graft in challenging clinical conditions

This report describes a useful technique for deployment of the Gore Hybrid Vascular Graft (W. L. Gore and Associates, Flagstaff, Ariz) in difficult clinical situations that create challenges in obtaining vascular control before introducing the nitinol-reinforced section of the graft. In both arterial and venous applications, introducing the Gore Hybrid Vascular Graft over a balloon allows concurrent vascular control by inflation of the balloon and easier introduction of the device into the recipient vessel by creating a smoother transition between the leading edge of thegraft and the guidewire. Examples of both arterial and venous applications of this novel technique are presented.

The Gore Hybrid Vascular Graft in renovisceral debranching for complex aortic aneurysm repair

This study reports our initial experience with the Gore Hybrid Vascular Graft (GHVG; W. L. Gore & Associates, Flagstaff, Ariz) for staged hybrid open renovisceral debranching and endovascular aneurysm repair in patients affected by thoracoabdominal aortic aneurysms and pararenal abdominal aortic aneurysms (PAAAs). Between December 2012 and December 2013, we analyzed outcomes of 13 patients who underwent open surgical debranching of renovisceral vessels for thoracoabdominal aortic aneurysm and PAAAs. All patients were considered at high risk for conventional surgery. Inclusion criterion was treatment by open surgical debranching of at least one visceral artery (renal artery, superior mesenteric artery [SMA], or celiac trunk [CT]) using the GHVG. In a second step, the aortic stent graft was implanted to exclude the aneurysm. If required, parallel grafts to the remaining visceral arteries were deployed in the same procedure. One patient had a symptomatic descending thoracic aortic aneurysm and another had a ruptured PAAA. Perioperative measured outcomes were immediate technical success rate, mortality, and morbidity. Median follow-up was 24.8months (range, 0-15; mean, 8.2; standard deviation, 4months). All open surgical debranching of renovisceral vessels were completed as intended. GHVG was used to revascularize 20 visceral vessels in 13 patients with a mean of 1.54 vessels per patient. Six renal arteries (30%; 2 right and 4 left), 9 SMAs (45%), and 5 CTs (25%) were debranched. In nine of 13 (66%) patients, other renovisceral arteries were addressed with chimney/periscope, Viabahn Open Revascularization Technique, and end-to-side anastomosis. Two of 13 patients (15%) died of bowel ischemia. Neither patient had GHVG revascularization to the SMA or CT. Perioperative complications occurred in three patients (23%; 1 renal hematoma, 1 respiratory insufficiency, and 1 small-bowel ischemia related to a SMA GHVG thrombosis). At 24months, estimated survival was 85%, and estimated primary and secondary patency were 94% and 100%, respectively. This limited series extracted from a more consistent hybrid procedure experience showed a mortality rate similar to most recent reports. Technical feasibility and the short-term patency rate of the GHVG for renovisceral debranching during staged hybrid open and endovascular procedures were satisfactory. Use of GHVGs may represent a useful revascularization adjunct to minimize visceral ischemia in these challenging patients.

Hybrid revascularization of the superior mesenteric artery in a patient with acute mesenteric ischemia and an occluded aorta

A 60-year-old man with a history of chronic mesenteric ischemia and chronic aortic occlusion presented with diffuse abdominal pain. On admission he was hypotensive and acidotic. A computed tomography angiogram revealed occlusion of his entire infrarenal aorta to the femoral arteries, an occluded celiac trunk and inferior mesenteric artery (previously stented), and severe stenosis of his superior mesenteric artery (SMA; A). He underwent explorative laparotomy, during which three segments of gangrenous small bowel were resected. The rest of the small bowel appeared ischemic but viable. Endovascular attempts to recanalize the SMA were unsuccessful. Owing to his hemodynamic instability and metabolic status, we performed a hybrid procedure. Under fluoroscopy, the thrombosed aorta was punctured. A wire and catheter were introduced into the thoracic aorta. After intraluminal position was confirmed, a 14F peel-away sheath was placed. A 6-mm hybrid vascular graft (W. L. Gore and Associates, Flagstaff, Ariz) was introduced (10-cm nitinol reinforced section and a 50-cm nonringed graft). The sheath was removed and the visible end of the nitinol section, which protruded through the aorta, was secured with stitches to the aortic wall. (model, B) An 8-mm ringed polytetrafluoroethylene graft was placed over the 6-mm graft to prevent kinking and the graft was anastomosed to the SMA. The remaining bowel improved immediately. Postoperative computed tomography angiography showed the hybrid graft was patent, with filling of the SMA (C and D/Cover).

Commentary: The Hybrid Vascular Graft

Commentary: The Hybrid Vascular Graft

Early Experience With a Novel Hybrid Vascular Graft for Hemodialysis Access Creation in Patients With Disadvantaged Anatomy

Purpose: To describe the use of the Hybrid vascular graft in disadvantaged anatomy for hemodialysis access creation and compare outcomes to standard-wall polytetrafluoroethylene (PTFE) grafts. Methods: In a retrospective analysis, 25 patients (mean age 65±14 years; 13 men) who received the Hybrid graft were compared with 35 contemporaneous patients (mean age 63±12 years; 20 men) who received a standard PTFE graft for hemodialysis access over a 2-year period. Criteria for Hybrid graft placement were (1) exhausted or inadequate peripheral veins for arteriovenous fistula (AVF) creation and concomitant small target veins that precluded conventional PTFE graft placement, (2) previous graft anastomosis or a stent in the venous target at the level of the axilla, or (3) failed brachial-basilic or brachial-brachial upper arm transposition AVF with a small target vein at the axilla. Efficacy, anatomic and clinical considerations, and technique were reviewed; patency rates, complications, and reinterventions were examined. Results: Technical success was achieved in all cases, and all grafts were usable for hemodialysis. Seven of 25 Hybrid patients required stent-graft extensions and 3 patients required angioplasty to improve venous outflow at the time of Hybrid graft insertion. Three of 35 standard PTFE graft patients required angioplasty to improve venous outflow at the time of graft insertion. There was no perioperative mortality or procedure-related morbidity in either group. Median follow-up was 21 months. The patient survival estimate was 66% at 2 years. Estimated primary patency (24% vs 18%, p>0.05), assisted primary patency (34% vs 28%; p>0.05), and secondary patency rates (40% vs 38%, p≥0.05) at 24 months were equivalent for Hybrid vs PTFE grafts, respectively. Venous hypertension was not a complication following Hybrid graft implantation but was seen in 2 patients with the standard PTFE graft. Conclusion: The Hybrid graft offers a safe, technically effective alternative for patients with disadvantaged anatomy requiring hemodialysis access and has comparable outcomes to standard PTFE grafts. Further clinical experience and long-term data are required for determining the proper utility of this device in chronic dialysis-dependent patients.

Fabrication and Short-Term in Vivo Performance of a Natural Elastic Lamina-Polymeric Hybrid Vascular Graft.

Although significant advances have been made in the development of artificial vascular grafts, small-diameter grafts still suffer from excessive platelet activation, thrombus formation, smooth muscle cell intimal hyperplasia, and high occurrences of restenosis. Recent discoveries demonstrating the excellent blood-contacting properties of the natural elastic lamina have raised the possibility that an acellular elastic lamina could effectively serve as a patent blood-contacting surface in engineered vascular grafts. However, the elastic lamina alone lacks the requisite mechanical properties to function as a viable vascular graft. Here, we have screened a wide range of biodegradable and biostable medical-grade polymers for their ability to adhere to the outer surface of the elastic lamina and allow cellular repopulation following engraftment in the rat abdominal aorta. We demonstrate a novel method for the fabrication of elastic lamina-polymeric hybrid small-diameter vascular grafts and identify poly(ether urethane) (PEU 1074A) as ideal for this purpose. In vivo results demonstrate graft patency over 21 days, with low thrombus formation, mild inflammation, and the general absence of smooth muscle cell hyperplasia on the graft's luminal surface. The results provide a new direction for developing small-diameter vascular grafts that are mass-producible, shelf-stable, and universally compatible due to a lack of immune response and inhibit the in-graft restenosis response that is common to nonautologous materials.

Results of the Gore Hybrid Vascular Graft in Challenging Aortic Branch Revascularization during Complex Aneurysm Repair

Prolonged organ ischemia during complex aortic surgery is associated with increased morbidity and mortality. A novel hybrid graft (Gore Hybrid Vascular Graft) ascomposite of expanded polytetrafluorethylene vascular prosthesis that has a section reinforced with nitinol was investigated for feasibility and effectiveness during aortic repair. Retrospective analysis of all consecutive patients treated with the hybrid vascular graft (HVG). Indication for graft implantation was surgeon's preference for branch revascularization in challenging aortic repair. Within 26months, 25 Gore HVGs and 17 conventional grafts were implanted in 12 patients (age, 73years; range, 33-79 years, 8 men). Eleven patients were treated for thoracoabdominal aortic aneurysms and one for aortoiliac aneurysm (elective=6, urgent=6). Nine visceral debranching procedures, 2 Crawford procedures, and 1 repair of an internal iliac aneurysm were performed. The distribution of HVG use was left renal artery=10, right renal artery=9, superior mesenteric artery=4, celiac trunk=1, and internal iliac artery=1. Time to restore visceral blood flow during visceral debranching was 7±4min for the Gore HVG vs. 12 ± 6min for conventional grafts (P<0.01).Technical success was achieved in all cases. At 12months of median follow-up, cumulative patency of the HVGs was 96%. The Gore HVG offers a new, simplified, and time-sparing technique for visceral anastomoses during complex aneurysm repair. However, long-term results are still lacking and need to be awaited.

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.

Open repair of an aortic aneurysm in a patient with Loeys-Dietz syndrome using Gore hybrid vascular branch grafts.

A 44-year-old woman with Loeys-Dietz syndrome (transforming growth factor-β [TGFBR2] gene mutation) presented with a retrograde type B dissection. She developed rapid expansion of the thoracoabdominal aortic false lumen aneurysm. The patient was successfully treated with open thoracoabdominal repair using Gore Hybrid Vascular Grafts (W. L. Gore and Assoc, Flagstaff, Ariz) for revascularization of the celiac trunk, the superior mesenteric artery, and both renal arteries. Follow-up imaging documented patency for all visceral branches. The described off-label use for sutureless revascularization might be a fast, simple, and reliable solution for revascularization during open thoracoabdominal repair. Furthermore, anastomotic aneurysm in patients with connective tissue disease might be prevented by sutureless anastomosis.

Hybrid Gore Vascular Graft: A New Tool for the Hybrid Treatment of Thoraco-Abdominal Aneurysms

The Hybrid procedure, first performed in 1999 by QuinonesBaldrich and colleagues [1], has been proposed for thoracoabdominal aneurysms (TAAA) repair as a less invasive technique than the traditional open surgery (avoiding both thoracophreno-laparotomy and aortic cross-clamping): in our Institute, the Hybrid technique has been performed since 2005 [2]. Since then, Literature showed several disadvantages: the overall duration of the procedure due to extensive dissections to prepare each visceral vessel and to make 5 to 7 anastomoses and the length of end-organ ischemia during the execution of each anastomosis (15 to 30 minutes) can cause critical rates of post-operative organ failure, morbidity and mortality [3]. Furthermore, nowadays total endovascular techniques make the Hybrid repair less attractive, but it can still be useful when you don’t have enough time (at least 3-4 weeks) to develop customized endovascular prosthesis. The new Gore® Hybrid Vascular Graft (HVG) can be a useful tool because it allows performing a “sutureless anastomosis” in a few minutes, and minimizes both the ischemia time of the target organ and the overall length of the operation. Effectively, this device is an ePTFE heparin bonded vascular prosthesis which has a section reinforced with nitinol. This part is partially constrained into a tubular shape to allow for easy insertion and deployment into a vessel. Gore® HVGs Instruction for Use (IFU) presents the device as a vascular prosthesis for replacement or bypass of diseased vessels in patients suffering occlusive or aneurysmal disease, for dialysis access, and in each patient requiring vascular replacement.

Use of a novel hybrid vascular graft for sutureless revascularization of the renal arteries during open thoracoabdominal aortic aneurysm repair

The aim of this study was to assess the safety and short-term effectiveness of a novel hybrid vascular graft used to address renal revascularization during open thoracoabdominal aortic aneurysm (TAAA) repair, performing a sutureless distal anastomosis. Between 2012 and 2013, 25 patients (16 men; mean age, 66 ± 8 years) underwent revascularization of one (24 patients) or both (one patient) renal arteries with the Gore Hybrid Vascular Graft (GHVG; W. L. Gore and Associates, Flagstaff, Ariz) during open TAAA repair. Specific indications included remote location of the ostium of the renal artery, severe atherosclerotic wall degeneration, focal dissection, and stenosis. All surviving patients underwent computed tomography angiography and follow-up visit at 1 month. Preoperative characteristics, intraoperative data, and short-term results were compared with those of 49 concurrent TAAA patients operated on within the same period by standard renal revascularization (SRR) techniques. All GHVG target renal vessels (26 of 26) were successfully revascularized without technical concerns. No significant differences were found between GHVG and SRR groups in preoperative and intraoperative data, except for a relative prevalence of aortic dissection (28% vs 6%; P = .026) and renal artery stenosis (44% vs 12%; P = .003) in the GHVG group and for intraoperative renal bare stenting that was predominantly used in the SRR group (12% vs 28%; P = .036). The 30-day mortality was 4% in both groups. Postoperative acute renal failure (doubling of creatinine level and creatinine level >3.0 mg/dL) occurred in two GHVG patients (8%) and seven SRR patients (14%; P = NS). Perioperative peak decrease of estimated glomerular filtration rate was lower in the GHVG group (26 ± 18 mL/min/1.73 m(2) vs 37 ± 22 mL/min/1.73 m(2); P = .034). At 1-month computed tomography angiography, renal artery patency was 92% for the GHVG vessels, 91% for the contralateral to GHVG renal vessels, and 92% for the SRR group arteries. No GHVG-related complications requiring reintervention or cases of new-onset renal failure requiring dialysis were observed at follow-up. Renal revascularization during open TAAA repair by the GHVG with distal sutureless anastomosis is feasible, especially in cases of aortic dissection, remote location of the renal vessel, and severe atherosclerotic disease of the ostium. Short-term results are satisfactory, at least comparable to those of SRR. Larger series and longer follow-up are needed to assess clinical advantages and durability of this new device.

Initial experience with a novel hybrid vascular graft for peripheral artery disease

This report describes the successful use of a new hybrid vascular graft as a conduit for above knee femoro-popliteal bypass surgery. The graft consists of a proximal (heparin coated) expanded polytetrafluoroethylene section but ends distally as a nitinol reinforced self-expandable stent that is covered and constrained, allowing a sutureless distal anastamosis. With this graft the creation of above knee bypasses in situations where lesions extend to the popliteal artery behind the knee, or in cases where the above knee popliteal artery is severely calcified is still possible. This avoids the necessity of an infragenicular bypass with potentially inferior long-term patency rates, especially when no autologous venous bypass material is available.

Arteriovenous Fistula Salvage Utilizing a Hybrid Vascular Graft

Loss of arteriovenous fistula as access for hemodialysis leads to significant morbidity and increased mortality risk. Maintenance of this access is of paramount importance and we describe a case of a patient with a functioning radiocephalic fistula with associated arm swelling due to poor narrow caliber venous drainage above the elbow but with normal central veins. A hybrid vascular graft was anastomosed to the upper extent of the fistula and the nitonol stent section introduced into the patent axillary vein. The described method led to resolution of symptoms and arm swelling. The described method allowed the continued use of a mature fistula.

Use of the Gore Hybrid Vascular Graft in a challenging high-lying extracranial carotid artery aneurysm

Extracranial carotid artery aneurysm is a rare condition with relatively significant morbidity and mortality. When surgery is not indicated, endovascular techniques are emerging as the preferred treatment. However, even this approach may be contraindicated due to anatomic factors. We present a case of a high-lying extracranial carotid artery aneurysm with challenging anatomy unsuitable for conventional or endovascular repair. After resecting the aneurysm, the carotid artery was revascularized using the new Gore Hybrid Vascular Graft (W. L. Gore & Associates, Flagstaff, Ariz). This straightforward procedure turned out to be safe and further reduced the cerebral ischemic time.

One-Stage Triple Hybrid Arch Debranching

Traditionally, repair of complex arch and descending aortic disease has required a two-stage surgical approach. We describe a novel one-stage repair that combines primary revascularization of the subclavian with stent coverage of diffuse aortic disease. A 31-year-old woman with Marfan syndrome presented with a growing arch aneurysm. At age 16 years, she had undergone the Ross procedure followed by a redo sternotomy and valve conduit. On follow-up, a distal arch aneurysm measuring 6 cm with an aneurysmal upper thoracic aorta and a localized distal thoracic aortic dissection was identified. In one stage, triple hybrid off-pump arch debranching with endovascular stent grafting was performed using two GORE Hybrid Vascular Grafts to perform the distal left carotid and subclavian anastomoses, which provided complete primary arch debranching without requiring a carotid-subclavian shunt. The patient had no complications, was discharged home on postoperative day 3, and continues to do well 3 months postoperatively. We conclude that one-stage repair of complex aortic arch disease with primary revascularization of the subclavian is feasible.

Use of Hybrid Vascular Grafts in Failing Access for Hemodialysis: Report of Two Cases

Purpose: Vascular access morbidity represents one of the most common indications for readmission in patients with end-stage renal disease (ESRD). We report the use of hybrid grafts in two patients for revision of failed vascular access for hemodialysis (HD). Case Presentations: The first patient was a 45-year-old woman with ESRD who presented with an arteriovenous graft (AVG) that had required multiple interventions for maintenance in whom much of the graft was lined with covered stents. The patient presented with erosion of a stent in the AVG through the skin to the emergency department. The second patient was a 41-year-old man with ESRD who also had an AVG that had required multiple interventions for maintenance. He presented to clinic with chronic bleeding from the AVG after HD sessions. Both patients were taken to the operating room for salvage of part of the AVG through the use of hybrid vascular access grafts. The patients have passed six and three months from the procedure, respectively, without needing additional interventions. Conclusions: This technique demonstrates successful use of hybrid vascular access grafts, specifically inside existing grafts in locations that contain stents utilizing the existing venous resources in that arm to carry out the surgical repair, thereby preserving venous capital.

Impact of various modifications of biodegradable membranous scaffolds surface on multipotent mesenchimal stromal cells adhesion and viability

Designing a hybrid vascular graft using biocompatible and biodegradable polymers is one of the ways to fill the market with vascular grafts of a small diameter necessary for coronary artery bypass surgery. Good adhesive properties of cultivated cells and low cytotoxicity of biopolymers can improve biocompatibility of polymer-based vascular grafts. The impact of protein modification of membranous polyhydroxyalkanoate and polycaprolactone scaffolds surface on their adhesive properties and cytotoxicity to multipotent mesenchimal stromal cells was evaluated. We used the following compositions of membranous scaffolds: № 1 polyhydroxybutyrate valerate ММ 2 307 kDa with polycaprolactone ММ 80 000 kDa, № 2 had the same composition but was made using a magnetic stirrer, №3 polyhydroxybutyrate ММ 541 kDa with polycaprolactone ММ 80 000 kDa and № 4 polycaprolactone ММ 80 000 kDa only. Premodification of scaffolds surfaces with 75, 50 and 25% fetal calf serum was found to significantly reduce cytotoxicity of scaffold № 4 and improve the adhesive properties of scaffolds № 1, 2 and 3. Premodification with fibronectin (10 µg/ml) mostly improved the adhesive properties of scaffolds № 1—4.

Aortic Aneurysmal Repair With Surtureless Visceral Revascularization Using Novel Hybrid Vascular Graft and a Gradual Funneling Technique

This article details a novel technique in the treatment of a symptomatic thoracoabdominal aneurysm (TAA) involving the visceral segment and an infrarenal abdominal aortic aneurysm. The patient was treated in a 2-staged hybrid approach combining an endovascular repair of the infrarenal segment, followed by open TAA repair. The large visceral arteries were revascularized using expanded polytetrafluoroethylene GORE Hybrid Vascular Graft (GHVG) and a Gradual Funneling Technique with Dacron graft. This method assured a complete hemostatic seal and minimized visceral ischemic time. To our knowledge, this is the first case of sutureless visceral artery revascularization using GHVG reported in the literature.

Abstract No. 431: Early outcomes of the “hybrid” graft used as a conduit for hemodialysis access

Achieving functional dialysis access in patients with few or hard to access open deep veins is an ongoing challenge. The development of new technologies may provide an alternative to conventional approaches and maximize the use of the extremity's venous real-estate while reducing the operative insult to these generally fragile patients. We describe our early experience with the hybrid vascular graft (W.L. Gore and Associates, Flagstaff, Ariz.) in 23 patients. The hybrid graft allows for a stented and sutureless distal anastomosis which can be performed using endovascular access. Selection criteria included: no acceptable peripheral alternative access site, previous graft anastomosis or a stent in the venous target at the level of the axilla, failed brachial-basilic upper arm transposition arteriovenous fistula or a target vein < 0.3 cm within the axilla. Patient demographics and early patency were evaluated. Technical success was accomplished in all 23 cases (100%), 7 required a Viabahn (W.L. Gore and Associates, Flagstaff, Ariz.) stent-graft extension and two additional patients percutaneous angioplasty (PTA) to improve venous outflow at the axillary and/or subclavian veins at the time of surgery. Eighteen patients are currently using the hybrid graft, one case of early failure occurred secondary to thrombosis. Two patients recently had the procedure and are not yet using their grafts. 2 patients developed dialysis associated steal syndrome (DASS) requiring plication of the inflow graft segment and one of them also required stenting of the brachial artery to improve inflow. During the follow up period two patients died of comorbidities nonrelated to the access procedure while having a functioning graft. The Hybrid graft concept appears to be a safe and technically effective alternative for patients with a disadvantaged anatomy in whom dialysis access is needed. Long-term data will be required to validate it as a preferential option in patients with limited venous real-estate.

A multilayered synthetic human elastin/polycaprolactone hybrid vascular graft with tailored mechanical properties

Small-diameter synthetic vascular graft materials fail to match the patency of human tissue conduits used in vascular bypass surgery. The foreign surface retards endothelialization and is highly thrombogenic, while the mismatch in mechanical properties induces intimal hyperplasia. Using recombinant human tropoelastin, we have developed a synthetic vascular conduit for small-diameter applications. We show that tropoelastin enhances endothelial cell attachment (threefold vs. control) and proliferation by 54.7 ± 1.1% (3 days vs. control). Tropoelastin, when presented as a monomer and when cross-linked into synthetic elastin for biomaterials applications, had low thrombogenicity. Activation of the intrinsic pathway of coagulation, measured by plasma clotting time, was reduced for tropoelastin (60.4 ± 8.2% vs. control). Platelet attachment was also reduced compared to collagen. Reductions in platelet interactions were mirrored on cross-linked synthetic elastin scaffolds. Tropoelastin was subsequently incorporated into a synthetic elastin/polycaprolactone conduit with mechanical properties optimized to mimic the human internal mammary artery, including permeability, compliance, elastic modulus and burst pressure. Further, this multilayered conduit presented a synthetic elastin internal lamina to circulating blood and demonstrated suturability and mechanical durability in a small scale rabbit carotid interposition model.