Stent-graft Component Research Articles

Fenestrated Aortic Arch Stent-Graft Malfunction With Endovascular Salvage

To describe a case of a fenestrated aortic stent-graft device malfunction in the aortic arch, which left the stent-graft deployed and almost irretrievable had it not been for an escalating series of endovascular salvage maneuvers. A 47-year-old man presented with a rapidly enlarging 6.9-cm thoracic aneurysm that was a complication of a chronic type B aortic dissection. A 2-piece, custom-made, tapered, fenestrated thoracic endoprosthesis (innominate scallop plus single carotid) was planned to seal from the innominate origin to immediately above the celiac axis after staged left carotid to subclavian bypass. Blood pressure control with rapid ventricular pacing aided deployment of the proximal, fenestrated stent-graft component with both openings accurately positioned over their respective branch vessel ostia. Attempted retrieval of the nosecone was hampered by a release failure of the single conformance tie that connects the stent-graft to its central cannula. This left the stent-graft fully deployed with the nosecone irretrievable beyond a point immediately distal to the small fenestration. A series of endovascular salvage maneuvers ensued, ranging from simple actions to manipulate and balloon dilate the graft through to more complex attempts to break the tie and lasso the nosecone using snares. Finally, attempts at antegrade retrieval of the nosecone straightened the device and released the offending tie, allowing case completion. This is a rare but cautionary example of the potential pitfalls of translating endograft technology from the abdominal aorta to the hostile environment of the aortic arch. It is likely that a combination of the arch curvature and hemodynamic forces, combined with the narrowed true lumen, contributed to failure of the trigger-wire tie release mechanism. Consideration of these endovascular salvage maneuvers may benefit interventional specialists who treat such diseases of the aortic arch.

Preservation of Hypogastric Artery Blood Flow During Endovascular Aneurysm Repair of an Abdominal Aortic Aneurysm With Bilateral Common and Internal Iliac Artery Involvement: Utilization of Off-the-Shelf Stent-Graft Components

A 72-year-old male presented with a 7.4-cm abdominal aortic aneurysm with bilateral common and internal iliac involvement. To maintain pelvic perfusion, preservation of the patient's left hypogastric artery (HA) was pursued. Two weeks after right HA embolization, endovascular repair of the patient's aneurysms was performed using a branched endograft approach. A 22-mm main body bifurcated endograft was unsheathed and the proximal covered stent was removed. The contralateral gate was preloaded with a wire and catheter. The device was resheathed and placed in the left common iliac artery. The preloaded wire in the contralateral gate was snared from the right side, establishing through-and-through femoral access. A contralateral femoral sheath was advanced up and over the aortic bifurcation from the right side into the contralateral gate of the bifurcated endograft. The repair was bridged to the left HA using a balloon-expandable stent-graft, followed by standard endovascular abdominal aortic aneurysm repair. Completion angiography demonstrated exclusion of patient's aneurysms, without evidence of endoleak, and maintenance of pelvic blood flow through the left HA. The patient recovered without complication and was discharged home on postoperative day 4. This technique illustrates the technical feasibility of using a preloaded commercially available endograft to preserve HA blood flow and maintain pelvic perfusion during endovascular aortic aneurysm repair.

Paraplegia prevention branches: A new adjunct for preventing or treating spinal cord injury after endovascular repair of thoracoabdominal aneurysms

In this report, we describe a technique that could potentially be used for both prevention and treatment of spinal cord ischemia (SCI) in endovascular repair of thoracoabdominal aneurysms. This technique involves using a specially designed endograft with side branches (paraplegia prevention branches [PPBs]), which are left patent to perfuse the aneurysmal sac and any associated lumbar or intercostal arteries in the early postoperative period. The use of PPBs with this technique is feasible and allows for a temporary controlled endoleak that may be useful for preventing or reversing spinal cord injury. This technique may be considered as an adjunct to the more standard perioperative physiological manipulations such as permissive hypertension and spinal fluid drainage.

Emergency Procedures on the Descending Thoracic Aorta in the Endovascular Era

Thoracic endovascular aortic repair (TEVAR), initially developed for the treatment of degenerative aneurysms of the descending thoracic aorta, has been applied to the entire spectrum of descending thoracic aortic pathology in both the elective and emergent settings. This single center study evaluates the effectiveness of TEVAR for the treatment of acute surgical emergencies involving the descending thoracic aorta, including traumatic aortic disruption (TAD), ruptured descending thoracic aneurysm (RDTA), and acute complicated type B dissection (cTBD). A retrospective review of the medical records of all patients undergoing emergent TEVAR at a tertiary care medical center with a level 1 trauma center between August 2007 and August 2010 was undertaken. Study endpoints included: 30-day survival, complications, type of device used for the repair and technical aspects of the procedure. A total of 42 patients (62% male) with an average age of 50 years underwent emergent TEVAR during the study period. The technical success rate was 100%, with no patient requiring emergent open surgery for conditions involving the descending thoracic aorta at our institution during the study period. The majority (71%) of the repairs were accomplished using commercially available thoracic stent grafts. Abdominal stent graft components were used in 40% of patients undergoing repair of TAD. Twenty patients (48%) required coverage of the left subclavian artery, two of whom subsequently required subclavian artery revascularization. Procedure related complications included: 1 stroke, 1 spinal cord ischemia, 1 unintentional coverage of the left carotid artery, 1 episode of acute renal failure and 2 access site injuries. Two patients undergoing repair of TAD had collapse of the stent graft in the early postoperative period. Both were successfully treated by placement of an additional stent graft. Seven patients (17%) died within 30 days of surgery. Three had successfully undergone repair of a TAD and died of associated injuries.Tabled 1Type of aortic pathologyMean age (range)Type of deviceSubclavian artery coverage30-day survivalTAD43 (16-77)Thoracic-1815 of 30 (50%)27 of 30 (90%)N = 30Abdominal-12RDTA68 (54-87)Thoracic - 73 of 7 (43%)4 of 7 (57%)N = 7cTBD67 (50-77)Thoracic-42 of 4 (50%)3 of 4 (75%)N = 4Distal aortic tear42Thoracic-101/1 (100%)N = 1Total50 (16-87)Thoracic-3020 of 42 (48%)35 of 42 (83%)N = 42Abdominal-12 Open table in a new tab Emergent TEVAR has become the treatment of choice for acute surgical emergencies involving the descending thoracic aorta. Short-term results compare favorably to published historic results for emergent open surgical procedures on the descending thoracic aorta. Survival is highest in patients undergoing repair of TAD. Using current stent graft technology, nearly all emergent conditions of the descending thoracic aorta can be successfully treated with TEVAR. Subclavian artery coverage is required in half of patients, and can be performed safely. A minority will subsequently require subclavian artery revascularization.

Reversal of Fortune: Induced Endoleak to Resolve Neurological Deficit After Endovascular Repair of Thoracoabdominal Aortic Aneurysm

To describe a direct anatomical treatment approach using an induced type Ib endoleak to increase spinal cord perfusion and reverse paraplegia occurring after endovascular exclusion of a type 2 thoracoabdominal aortic aneurysm (TAAA). The approach is illustrated in an 82-year-old woman who underwent branched endovascular repair of an asymptomatic, 6.8-cm-diameter type 2 TAAA. In 4-hour procedure, 3 aortic components were implanted beginning 50 mm distal to the origin of the left subclavian artery and ending 33 mm proximal to the aortic bifurcation. Upon awakening, the patient had sluggish movement in her legs. She responded to vasoactive agents and cerebrospinal fluid (CSF) drainage, but 3 recurrent episodes of paraplegia within 24 hours and severe headache indicated that the limits of CSF drainage had been reached. The patient was taken back to the operating room, and a type Ib (distal) endoleak was created by placing a balloon-expandable stent between the distal end of the infrarenal stent-graft component and the aortic wall, partially re-establishing flow into the aneurysm. The patient had no further recurrence of lower extremity paraplegia or paraparesis. At 3.5 months postoperatively, a Palmaz stent was deployed inside the distal end of the infrarenal stent-graft component to crush and occlude the Express LD stent, re-establishing a complete seal to preclude flow into the aneurysm. The patient remains clinically stable without lower extremity neurological deficit 3 months after the last procedure and 7 months after endovascular TAAA repair. A direct anatomical approach to reverse spinal cord ischemia following endovascular TAA or TAAA repair is feasible by creating a type I or type III endoleak to afford partial, temporary reperfusion of the excluded aorta.

Pivotal results of the Medtronic Vascular Talent Thoracic Stent Graft System: The VALOR Trial

This report summarizes the 30-day and 12-month results of endovascular treatment using the Medtronic Vascular Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, Calif) for patients with thoracic aortic aneurysms (TAA) who are considered candidates for open surgical repair. The study was a prospective, nonrandomized, multicenter, pivotal trial conducted at 38 sites. Enrollment occurred between December 2003 and June 2005. Standard follow-up interval examinations were prescribed at 1 month, 6 months, 1 year, and annually thereafter. These endovascular results were compared with retrospective open surgical data from three centers of excellence. The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial enrolled 195 patients, and 189 were identified as retrospective open surgical subjects. Compared with the open surgery group, the VALOR test group had similar age and sex distributions, but had a smaller TAA size. Patients received a mean number of 2.7 +/- 1.3 stent graft components. The diameters of 25% of the proximal stent graft components implanted were <26 mm or >40 mm. Left subclavian artery revascularization was performed before the initial stent graft procedure in 5.2% of patients. Iliac conduits were used in 21.1% of patients. In 33.5% of patients, the bare spring segment of the most proximally implanted device was in zones 1 or 2 of the aortic arch. In 194 patients (99.5%), vessel access and stent graft deployment were successful at the intended site. The 30-day VALOR results included perioperative mortality, 2.1%; major adverse advents, 41%; incidence of paraplegia, 1.5%; paraparesis, 7.2%; and stroke, 3.6%. The 12-month VALOR results included all-cause mortality, 16.1%; aneurysm-related mortality, 3.1%; conversion to open surgery, 0.5%; target aneurysm rupture, 0.5%; stent graft migration >10 mm, 3.9%; endoleak (12.2%), stent graft patency, 100%; stable or decreasing aneurysm diameter, 91.5%; and loss of stent graft integrity, four patients. No deployment-related events or perforation of the aorta by a graft component occurred. The Talent Thoracic Stent Graft showed statistically superior performance with respect to acute procedural outcomes (P < .001), 30-day major adverse events (41% vs 84.4%, P < .001), perioperative mortality (2% vs 8%, P < .01), and 12-month aneurysm-related mortality (3.1% vs 11.6%, P < .002) vs open surgery. The pivotal VALOR 12-month trial results demonstrate that the Medtronic Talent Thoracic Stent Graft System is a safe and effective endovascular therapy as an alternative to open surgery in patients with TAA who were considered candidates for open surgical repair.

Endovascular Repair of a Thoracic Aortic Injury in a Burn Patient

Mortality in burn patients who sustain concomitant mechanical traumatic injuries at the time of thermal injury is greater than in patients who sustain isolated injuries. Invasive interventions to treat these mechanical traumatic injuries may be a source of added mortality and contribute to an injury-induced state of immunosuppression. Less-invasive interventions may minimize morbidity and mortality and allow for improved recovery from thermal injury. A case is presented of a patient who sustained 20% TBSA electrical burns and an acute thoracic aortic injury near the diaphragmatic hiatus. Abdominal aortic stent-graft components were used to successfully exclude the patient's thoracic aortic injury. The patient made a successful recovery from his burns and sustained no infectious complications. This case report highlights the potential advantages of endovascular therapy for the treatment of aortic trauma in patients who sustain concomitant burn injuries.

Late Perforation of a Thoracic Aortic Dacron Graft by a Metallic Stent-Graft Component

To describe a case involving perforation of a previously placed aortic Dacron graft by the uncovered proximal stent of a thoracic stent-graft. A 76-year-old man with a surgically treated type A dissection presented with residual type B dissection. Thoracic stent-grafting of the entry site was performed successfully. After 2 years, the patient was admitted for evaluation of a non-pulsating parasternal mass. Computed tomography showed a large, hypodense liquid-like mass affecting the mediastinum up to the subcutaneous tissue. A false aneurysm at the proximal end of the stent-graft was observed arising from an aortic perforation by the uncovered stent. One week later, the mass had almost completely resolved, and the patient has been scheduled for close surveillance. This case illustrated the importance of thoroughly examining the long-term durability and compatibility of prosthetic materials.

Early outcomes after elective and emergent endovascular repair of the thoracic aorta

Endovascular treatment of thoracic aortic pathology has emerged as a viable alternative to open surgical repair in both the elective and emergent settings. The aim of this study was to evaluate preoperative work-up, intra-operative strategy, and outcomes of endovascular stent-grafting of the thoracic aorta in patients undergoing elective repair and those undergoing emergent repair. All patient information was obtained by a retrospective review of an established clinical database for all endovascular thoracic stent-graft cases. From October 1999 to August 2005, 70 patients were treated with endovascular stent-grafts for lesions of the thoracic aorta. Thirty-five patients had an elective endovascular procedure, and 35 patients had an emergent procedure. Thirty-five patients in the endovascular (EL) group were treated for aneurysm (n = 34) and type B dissection (n = 1). Thirty-five patients in the emergent (EM) group were treated for aneurysm (n = 10), intramural hematoma (n = 10), type B dissection (n = 7), traumatic rupture (n = 7), and aortoesophageal fistula (n = 1). Preoperative angiography was performed in 94.3% (33/35) of EL patients but in only 45.7% (16/35) EM patients (P < .005). The EM procedures had significantly shorter operative times, used lower contrast volumes, used fewer stent-graft components (mode 2, range 1 to 5 vs mode 1, range 1 to 3; P = .02), and spinal cerebrospinal fluid drains were used significantly less often (82.9% vs 57.1%, P = .04). Both groups had similar 30-day morbidity, mortality (0/35 EL vs 1/35 [2.9%] EM, P = .99), postoperative endoleak (9/35 [25.7%] EL vs 7/35 [20.0%] EM, P = .78), endovascular failure (3/35 [8.6%] EL vs 5/35 [14.3%] EM, P = .71), and patient survival. There are significant differences in the underlying pathology, preoperative evaluation, and operative course between elective and emergency treatment endovascular procedures for lesions of the thoracic aorta. Endovascular repair of thoracic aortic lesions can be accomplished with low perioperative mortality and morbidity rates, as well as acceptable endoleak and endovascular failure rates for both elective and emergency procedures.

In Vitro Analysis of Modular Aortic Stent-Graft Failure

To investigate the theoretical forces involved in and the nature of fixation between the modular components of a variety of aortic stent-grafts. An in vitro study of 6 aortic stent-grafts was performed using a tensometer. The modular stent-graft components were distracted until the iliac limb was completely separated from the main body. Tests were repeated at least 6 times for each stent-graft. The maximum pullout force was 36.0 N using the Fortron stent-graft, which resulted in stent-graft disintegration. The maximum median forces of the other stent-grafts were 23.7 N (19.9-31.2) for the Aorfix, 7.3 N (6.9-7.6) for the AneuRx, 7.0 N (6.8-7.1) for the Zenith BiFab, 5.4 N (5.0-6.5) for the Talent, and 2.4 N (2.2-2.4) for the Vanguard II CONCLUSION: The results of this in vitro study suggest that current forms of iliac limb fixation in modular aortic stent-grafts are adequate provided the components are deployed with sufficient overlap. However, for many of the stent-grafts tested, the safety margin was small.

Endovascular repair of lesions involving the descending thoracic aorta

Vascular lesions involving the thoracic aorta are often life-threatening conditions that carry significant morbidity and mortality with traditional open surgical repair. Preliminary results suggest that endovascular therapy is an effective and possibly advantageous treatment for diseases of the descending thoracic aorta. Between October 2000 and May 2004, 50 consecutive patients underwent endovascular stent-grafting of lesions involving the descending thoracic aorta. Attempted stent-graft deployment was performed electively in 39 patients and emergently in 11. The pathology of electively treated aortic lesions included degenerative/atherosclerotic aneurysms (n = 24), pseudoaneurysms (n = 11), aortic dissections (n = 2), and penetrating ulcers (n = 2). Emergently treated aortic lesions were for acute rupture due to infectious (mycotic) aneurysms (n = 4), atherosclerotic/degenerative aneurysms (n = 3), acute type B dissections (n = 2), and acute transections (n = 2). Devices used include Talent (n = 45), AneuRx aortic cuffs (n = 2), custom-fabricated Gianturco-Dacron grafts (n = 2), and a modified Cook-Zenith abdominal aortic graft (n = 1). Follow-up was performed at 1-month, 6-months, 1-year, and annually thereafter. Primary technical success, defined as successful deployment and exclusion of the lesion without evidence of type I or type III endoleak, was achieved in 48 (96%) of 50 patients. In one patient, the procedure was terminated due to inability to access the iliac vessels. In another patient, a type III endoleak was observed at the completion of the primary procedure that required deployment of an additional stent-graft component 2 months later. Of the 49 patients who received endografts, seven underwent secondary procedures to correct endoleaks, with five of these seven requiring the deployment of additional endovascular stent-graft components. Major complications included four in-hospital deaths, with three of these occurring in patients treated emergently. Additionally, respiratory failure (n = 6), multisystem organ failure (n = 2), cerebrovascular accident (n = 2), retroperitoneal hematoma (n = 2), acute renal insufficiency (n = 1), and pulmonary embolus (n = 1) were also observed. The overall endoleak rate was 20%, with five primary (< or = 30 days) and five secondary (> 30 days) endoleaks observed. Five of the endoleaks were treated with the deployment of one or more additional endovascular stent-graft components. Two of the endoleaks were treated with endovascular balloon remolding. Mean follow-up was 271 days. There were no aneurysm ruptures or aneurysm-related deaths. Endovascular treatment of vascular lesions involving the descending thoracic aorta can be safely performed with low morbidity in high-risk patients. Endovascular repair may become an attractive alternative for the treatment of a wide range of pathology along this vascular territory.

Fibrin Glue Aneurysm Sac Embolization at the Time of Endografting

To describe the procedural details for primary prevention of type II endoleak with fibrin glue injection into the aneurysm sac at the time of endografting. After deployment of the main stent-graft component, the angiographic pigtail catheter is withdrawn, leaving the 0.035-inch standard guidewire between the endograft and the native aorta. Through a brachial-femoral arterial guidewire loop, an 11-cm-long, 6-F introducer is advanced over the wire into the contralateral iliac artery. After deployment of the contralateral iliac extension, a 23-cm, 5-F sheath is advanced over the wire into the aneurysm sac. The wire and vessel dilator are removed, leaving the cannula in the sac. To prevent distal embolization of the sealant, a balloon is inflated in the contralateral limb to secure it to the native vessel before 5 mL of fibrin sealant are injected into the sac via a double-syringe delivery system inserted through the sheath. The balloon is left in place for 1 minute after sealant injection. In 64 consecutive patients in whom this technique has been used, sac embolization has been successful. There have been no intraoperative complications or in-hospital mortality. Over a mean follow-up of 9.3+/-4.4 months (range 1-18), only 1 lumbar endoleak has been detected on surveillance imaging. This preventive strategy appears to be an effective approach and the best therapeutic choice for preventive management of type II endoleak.

Diaphragmatic Paralysis after Endovascular Stent Grafting of a Thoracoabdominal Aortic Aneurysm

Diaphragmatic Paralysis after Endovascular Stent Grafting of a Thoracoabdominal Aortic Aneurysm

Endovascular Repair of Recurrent Thoracoabdominal Aortic Aneurysm

To report the endovascular repair of a complicated, recurrent thoracoabdominal aortic aneurysm (TAAA) using stacked, customized stent-grafts. A 75-year-old man was evaluated for an enlarging 7-cm suprarenal abdominal aortic aneurysm. The patient had repair of a distal TAAA in the past, as well as multiple visceral revascularizations from the infrarenal aorta. A 3-segment aortic endograft with proximal and distal extensions was delivered with the aid of a prosthetic conduit from the right common iliac artery to the end of the right renal artery; spinal fluid drainage was performed to mitigate paraplegia. The stent-graft components were serially deployed from the level of the left common carotid artery and ended with the bare springs of the distal extension covering the renal arteries. The patient was discharged but returned within a month for drainage of a purulent retroperitoneal hematoma. He has since resumed his preoperative activities and remains well with documented exclusion of the aneurysm and satisfactory visceral and distal perfusion at 21 months. This case illustrates that aortic endografting can be a viable option for the treatment of recurrent thoracoabdominal aortic aneurysms.