Darren B. Schneider

Modular branched stent graft for endovascular repair of aortic arch aneurysm and dissection

PURPOSE We describe a modular stent graft for use in endovascular repair of aneurysms of the aortic arch. METHOD Carotid-carotid and left carotid-subclavian bypass grafts are created surgically. Two large, fully stented grafts are inserted endoluminally. The proximal component is bifurcated, with a wide proximal trunk and two distal limbs, one long and narrow, the other short and wide. This component is inserted through the carotid artery and deployed with the trunk and short wide limb in the ascending thoracic aorta; the long narrow limb opens into the innominate artery. After delivery system removal and carotid artery repair, a distal component is inserted through a femoral approach to bridge the gap between the short, wide distal limb of the proximal component and the nondilated descending thoracic aorta. The result is a branched stent graft, implanted proximally into the ascending aorta and distally into the innominate artery and descending thoracic aorta. CONCLUSION The system has been used successfully to treat a large wide-necked pseudoaneurysm of the aortic arch.

Heparin-bonded, Expanded Polytetrafluoroethylene-lined Stent Graft in the Treatment of Femoropopliteal Artery Disease: 1-Year Results of the VIPER (Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease) Trial

PURPOSE To evaluate the performance of a heparin-bonded, expanded polytetrafluoroethylene (ePTFE)-lined nitinol endoprosthesis in the treatment of long-segment occlusive disease of the femoropopliteal artery (FPA) and to identify factors associated with loss of patency. MATERIALS AND METHODS In a single-arm, prospective, 11-center study (VIPER [Gore Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease] trial), 119 limbs (113 patients; 69 men; mean age, 67 y), including 88 with Rutherford category 3-5 disease and 72 with Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) C or D lesions of the FPA, underwent stent graft implantation. The mean lesion length was 19 cm; 56% of lesions were occlusions. Follow-up evaluations included color duplex ultrasonography in all patients, with patency defined as a peak systolic velocity ratio< 2.5. RESULTS At 12 months, Rutherford category and ankle-brachial index (ABI) were significantly improved (mean category improvement, 2.4; ABI increased from 0.6±0.2 to 0.9±0.19; P<.0001). Primary and secondary patency rates were 73% and 92%. The primary patency for devices oversized<20% at the proximal landing zone was 88%, whereas the primary patency for devices oversized by>20% was 70% (P = .047). Primary patency was not significantly affected by device diameter (5 vs 6 vs 7 mm) or lesion length (≤20 cm vs>20 cm). The 30-day major adverse event rate was 0.8%. CONCLUSIONS The heparin-bonded, ePTFE/nitinol stent graft provided clinical improvement and a primary patency rate of 73% at 1 year in the treatment of long-segment FPA disease. Careful sizing of the device relative to vessel landing zones is essential for achieving optimal outcomes.

A Double-Barrel Stent-Graft for Endovascular Repair of the Aortic Arch

Purpose: To extend the role of endovascular aneurysm repair in the presence of angulation and dilatation of the distal arch that compromise the proximal implantation site. Case Report: A 70-year-old man with an asymptomatic 7-cm thoracic aortic aneurysm was treated with a TAG stent-graft. However, attempts to gain secure hemostatic implantation of the endograft resulted in inadvertent coverage of the subclavian and left carotid arteries. Flow to the left carotid artery was re-established by transcarotid insertion of a self-expanding covered stent alongside the primary stent-graft. Conclusion: This technique may have a role as an intended part of endovascular repair when there is no suitable implantation site in the descending thoracic aorta.

Expression of Fas Ligand in Arteries of Hypercholesterolemic Rabbits Accelerates Atherosclerotic Lesion Formation

Fas ligand (FasL) is expressed by cells of the arterial wall and is present in human atherosclerotic lesions. However, the role of FasL in modifying the initiation and progression of atherosclerosis is unclear. To investigate the role of arterial FasL expression in the development of atherosclerosis, we first established a model of primary lesion formation in rabbit carotid arteries. In this model, infusion of adenoviral vectors into surgically isolated, nondenuded arteries of hypercholesterolemic rabbits leads to the formation of human-like early atherosclerotic lesions. Expression of FasL in arterial endothelium in this model decreased T-cell infiltration and expression of vascular cell adhesion molecule-1 but did not affect expression of intercellular adhesion molecule-1. Intimal lesions grew more rapidly in FasL-transduced arteries than in arteries transduced with a control adenovirus that did not express a transgene. Total intimal macrophage accumulation was increased in FasL-transduced arteries; however, the proportion of lesion area occupied by macrophages was not elevated. The accelerated lesion growth was primarily due to the accumulation of intimal smooth muscle cells with a synthetic proliferative phenotype. There was no significant apoptosis in FasL-transduced or control arteries and no granulocytic infiltrates. Thus, the net result of elevated FasL expression is to accelerate atherosclerotic lesion growth by increasing lesion cellularity. Vascular expression of FasL may contribute to the progression of atherosclerosis.

Double-barrel technique for endovascular exclusion of an aortic arch aneurysm without sternotomy.

Purpose: To report the use of commercially available stents and a stent-graft in coaxial orientation to extend the proximal limits of endografting within the aortic arch. Case Report: A 70-year-old man was found to have an asymptomatic 7-cm saccular aortic arch aneurysm, extending distally from the origin of the left carotid artery and involving the left subclavian artery; there was only 11 mm between the innominate artery orifice and the aneurysm. The patient was deemed to be high risk for open surgical repair due to a history of 2 prior sternotomies and the requirement for hypothermic circulatory arrest. A “double-barrel” stent-graft strategy combining retrograde placement of an innominate stent with thoracic stent-graft implantation into zone 0 was successfully executed. The patient has continued to fare well after 10 months on close follow-up. Conclusion: The “double-barrel” stent technique may extend the limits of thoracic endografting by preserving the aortic arch branches while avoiding the need for sternotomy. Using this technique, proximal fixation can be obtained well into the ascending aorta using commercially available devices.

Double-Barrel Technique for Preservation of Aortic Arch Branches During Thoracic Endovascular Aortic Repair

Thoracic endovascular aortic repair (TEVAR) may involve either planned or inadvertent coverage of aortic branch vessels when stent grafts are implanted into the aortic arch. Vital branch vessels may be preserved by surgical debranching techniques or by placement of additional stents to maintain vessel patency. We report our experience with a double-barrel stent technique used to maintain aortic arch branch vessel patency during TEVAR. Seven patients underwent TEVAR using the double-barrel technique, with placement of branch stents into the innominate (n = 3), left common carotid (n = 3), and left subclavian (n = 1) arteries alongside an aortic stent graft. Gore TAG endografts were used in all cases, and either self-expanding stents (n = 6) or balloon-expandable (n = 1) stents were utilized to maintain patency of the arch branch vessels. In three cases the double-barrel stent technique was used to restore patency of an inadvertently covered left common carotid artery. Four planned cases involved endograft deployment proximally into the ascending aorta with placement of an innominate artery stent (n = 3) and coverage of the left subclavian artery with placement of a subclavian artery stent (n = 1). TEVAR using a double-barrel stent was technically successful with maintenance of branch vessel patency and absence of type I endoleak in all seven cases. One case of zone 0 endograft placement with an innominate stent was complicated by a left hemispheric stroke that was attributed to a technical problem with the carotid-carotid bypass. On follow-up of 2-18 months, all double-barrel branch stents and aortic endografts remained patent without endoleak, migration, or loss of device integrity. The double-barrel stent technique maintains aortic branch patency and provides additional stent-graft fixation length during TEVAR to treat aneurysms involving the aortic arch. Moreover, the technique uses commercially available devices and permits complete aortic arch coverage (zone 0) without a sternotomy. Although initial outcomes are encouraging, long-term durability remains unknown.

A modular multi-branched system for endovascular repair of bilateral common iliac artery aneurysms.

PURPOSE To describe a modular stent-graft for cases of bilateral common iliac aneurysm. TECHNIQUE The aortic aneurysm is repaired using a standard bifurcated modular system (Zenith). A modified bifurcated component is deployed with its trunk in one limb of the original aortic stent-graft, its long limb in the external iliac artery, and its short limb in the iliac aneurysm just above the internal iliac orifice. A flexible extension is introduced from the right brachial artery and used to bridge the gap between the short limb of the modified bifurcated component and the left internal iliac artery. CONCLUSIONS Endovascular repair of bilateral iliac aneurysm is feasible using a modular stent-graft with separate branches to the internal and external iliac arteries.

Statin therapy is associated with superior clinical outcomes after endovascular treatment of critical limb ischemia

OBJECTIVE The aim of this study was to determine if statin therapy improves clinical outcomes after endovascular intervention in patients with critical limb ischemia (CLI). METHODS A retrospective review of all patients undergoing endovascular treatment for CLI was performed. Two groups were created according to whether they were receiving statin therapy at the time of intervention. Demographics, lesion morphology, overall mortality, primary and secondary patency, and limb salvage were compared between these groups. Analysis was performed using multivariate regression and Kaplan-Meier analysis. RESULTS Between 2004 and 2009, 646 patients, 319 receiving statin therapy and 327 without, underwent an endovascular intervention for CLI. The statin group had significantly higher rates of diabetes mellitus, coronary artery disease, congestive heart failure, previous myocardial infarction, and coronary artery bypass grafting (P < .05). The two groups had similar lesion length, location, lesion type, TransAtlantic Inter-Society Consensus (TASC) classification, and primary procedure. At 24 months, the statin-treated group had higher rates of primary patency (43% vs 33%; P = .007), secondary patency (66% vs 51%; P = .001), limb salvage (83% vs 62%; P = .001), and overall survival (77% vs 62%; P = .038). Statin therapy was also independently associated with improved limb salvage by multivariate regression analysis (hazard ratio, 2.55; P < .001). CONCLUSIONS Patients who were receiving statin therapy when they underwent interventions to treat CLI had significantly improved overall survival, primary and secondary patency, and limb salvage rates. Our findings suggest that statins should be part of the periprocedural treatment regimen and support further investigation into the beneficial effects of statins in patients undergoing endovascular treatment of CLI.

Development of a Branched Stent-Graft for Endovascular Repair of Aortic Arch Aneurysms

Purpose: To develop a branched stent-graft for endovascular repair of aortic arch aneurysm. Methods: Four different prototypes of a branched aortic stent-graft were inserted into a rubber model of the human aortic arch under fluoroscopic guidance. Each prototype was tested, modified, and tested again through a series of 4 iterations. The first 3 prototypes had multiple short side branches, as docking sites for extensions into the branches of the aortic arch. The last iteration had only 1 short branch for an extension into the distal aorta and 1 long branch for direct perfusion of the innominate artery. Results: With every re-design, the prototype aortic stent-graft became shorter, and its insertion site moved to a more proximally located arch artery. Stent-graft insertion, orientation, and extension also became quicker and easier with each change in device design. However, the only system to perform reliably was the last, which was subsequently used to treat a large, symptomatic pseudoaneurysm of the aortic arch in a high-risk patient. Conclusions: None of our multibranched systems was simple, safe, or durable enough for insertion into the aortic arch; only an iteration that had a short branch for an extension into the distal aorta and a long branch for direct perfusion of the innominate artery could be deployed without difficulty or delay.

Branched endovascular repair of aortic arch aneurysm with a modular stent-graft system

A 60-year-old man with new-onset chest and back pain was found at computed tomography to have a 6-cm pseudoaneurysm of the aortic arch at the site of open surgical repair of an arch aneurysm 6 years previously. The history was notable for severe chronic obstructive pulmonary disease, previous coronary artery stenting, and type IV thoracoabdominal aneurysm repair. An arch aortogram showed a wide-necked, saccular pseudoaneurysm of the aortic arch, originating opposite the left common carotid artery (A). Because of poor cardiopulmonary function and previous arch surgery, the patient was considered at prohibitive risk for traditional open aneurysm repair. Endovascular repair of the aortic arch pseudoaneurysm was performed with the patient under general anesthesia, with a branched modular stent-graft device and insertion procedure, described in an accompanying article in this issue of the Journal. The bifurcated stent graft directed all flow from the ascending aorta into the innominate artery and descending thoracic aorta while excluding flow to the aneurysm. Preparatory reconstruction of the brachiocephalic circulation included carotid-carotid bypass grafting, transposition of the left subclavian artery, and implantation of the left vertebral artery into the left subclavian artery. The operation required 6 hours. Completion angiograms revealed proper graft placement, with perfusion of all brachiocephalic arteries and no endoleak (B). These findings were confirmed on postoperative computed tomography scans (C, Cover). Recovery was complicated by a week-long period of ventilatory support and an episode of atrial flutter. There were no cardiac or neurologic complications. The patient was discharged home with warfarin for prophylaxis against cerebral thromboembolism. Conventional repair of aortic arch aneurysm or dissection requires sternotomy and graft replacement, usually with deep hypothermic circulatory arrest, with high morbidity and mortality. Despite the appeal of less invasive techniques, development of an endovascular system has been slowed by site-specific challenges such as the need to maintain uninterrupted cerebral perfusion. We believe that this case illustrates the advantages of a modular approach that combines well-tried stentgraft components and techniques in a new application. The only previously reported case of endovascular arch repair involved deployment of a complicated unibody, branched stent graft. Its successful deployment reflected a level of technical skill that has not been replicated. If our method of aortic arch repair proves both durable and reproducible, potential applications might include not only aneurysms of the arch, but also some type A dissections.