Thoracic Aortic Stent Graft Research Articles

Thoracic endograft in traumatic aortic injury — an other job for cardiologist in University Hospital Center Zagreb

Cardiologia CROATICA 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 including emergent settings. Last year in our institution, three patients with an average age of 46,6 years (range 39-55) underwent emergent TEVAR for acute aortic injury during traffic accident; two in the car, and one on the motorcycle. The technical success rate was 100%. A standard Medtronic thoracic aortic stent graft VALIANT was used. There was no procedure-related complications: no stroke, spinal cord ischemia, or complications connected with vascular access. In all three cases graft was positioned bellow left subclavian artery. All three patients had polytrauma, and after successful graft implantation underwent other surgical procedures (ruptured diaphragm, subdural hematoma, multiple pelvic fractures). Fortunately all three patients overcome their complicated medical conditions. The control MSCT of aorta, before hospital discharge, has shown widely patent stent grafts with no migration and no change in the configuration. After 1 year, 8 month and 6 month of follow up, our patients confirm that TEVAR is a reliable method for the treatment of traumatic thoracic aortic injuries, even favorable in comparison with historical open surgery, with good results in the shortand medium-term follow-up.

Computer modeling for the prediction of thoracic aortic stent graft collapse

To assess the biomechanical implications of excessive stent protrusion into the aortic arch in relation to thoracic aortic stent graft (TASG) collapse by simulating the structural load and quantifying the fluid dynamics on the TASG wall protrusion extended into a model arch. One-way coupled fluid-solid interaction analyses were performed to investigate the flow-induced hemodynamic and structural loads exerted on the proximal protrusion of the TASG and aortic wall reconstructed from a patient who underwent traumatic thoracic aortic injury repair. Mechanical properties of a Gore TAG thoracic endoprosthesis (W. L. Gore and Assoc, Flagstaff, Ariz) were assessed via experimental radial compression testing and incorporated into the computational modeling. The TASG wall protrusion geometry was characterized by the protrusion extension (PE) and by the angle (θ) between the TASG and the lesser curvature of the aorta. The effect of θ was explored with the following four models with PE fixed at 1.1 cm: θ = 10 degrees, 20 degrees, 30 degrees, and 40 degrees. The effect of PE was evaluated with the following four models with θ fixed at 10 degrees: PE = 1.1 cm, 1.4 cm, 1.7 cm and 2.0 cm. The presence of TASG wall protrusion into the aortic arch resulted in the formation of swirling, complex flow regions in the proximal luminal surface of the endograft. High PE values (PE = 2.0 cm) led to a markedly reduced left subclavian flow rate (0.27 L/min), low systolic perfusion pressure (98 mm Hg), and peak systolic TASG diameter reduction (2 mm). The transmural pressure load across the TASG was maximum for the model with the highest PE and θ, 15.2 mm Hg for the model with PE = 2.0 cm and θ = 10 degrees, and 11.6 mm Hg for PE = 1.1 cm and θ = 40 degrees. The findings of this study suggest that increased PE imparts an apparent risk of distal end-organ malperfusion and proximal hypertension and that both increased PE and θ lead to a markedly increased transmural pressure across the TASG wall, a load that would portend TASG collapse. Patient-specific computational modeling may allow for identification of patients with high risk of TASG collapse and guide preventive intervention. A potentially devastating complication that may occur after endovascular repair of traumatic thoracicaortic injuries is stent graft collapse. Although usually asymptomatic, stent graft collapse may be accompanied by adverse hemodynamic consequences. Numerous anatomic and device-related factors contribute to the development of collapse, but predictive factors have not yet been clearly defined. In the present study, we assessed the relevant hemodynamics and solid mechanics underlying stent graft collapse using a computational fluid-structure interaction framework of stent graft malapposition. Our findings suggest that both increased stent graft angle and extension into the aortic arch lead to a markedly increased transmural pressure across the stent graft wall, portending collapse. Patient-specific computational modeling may allow for identification of patients at high risk for collapse and aid in planning for an additional, prophylactic intervention to avert its occurrence.

One-Year Safety and Efficacy of Thoracic Aortic Stent Grafting (TEVAR) in Patients Who Are Poor Open Surgical Candidates: Results of the High-Risk Arm of the Valor Trial

One-Year Safety and Efficacy of Thoracic Aortic Stent Grafting (TEVAR) in Patients Who Are Poor Open Surgical Candidates: Results of the High-Risk Arm of the Valor Trial

In Situ Fenestration of the Internal Iliac Artery as a Bailout Technique Associated With Endovascular Repair of an Abdominal Aortic Aneurysm: Long-term Follow-up

To describe a bailout technique for in situ fenestration of an inadvertently covered internal iliac artery (IIA) associated with endovascular repair of an abdominal aortic aneurysm (AAA). The procedure is demonstrated in a 76-year-old patient who underwent elective repair of a 5-cm infrarenal AAA using an Excluder endovascular graft 2 years following thoracic aortic stent-graft repair of a chronic type B aortic dissection. A completion angiogram demonstrated unintentional coverage of the left IIA. The iliac limb of the stent-graft was not able to be displaced away from the ostium, so to preserve IIA perfusion in a patient with prior thoracic aortic stent-grafting, a bailout technique was performed using an Outback re-entry device to successfully fenestrate the polytetrafluoroethylene graft material. An iCast balloon-expandable stent was placed across the fenestration creating a patent side branch to maintain patency. Six-year follow-up demonstrates a stable repair. In situ fenestration of a stent-graft overlying the internal iliac artery can be a useful bailout technique when other options are unsuccessful.

TCT-127 The Impact of Later Generation Thoracic Aortic Stent Grafts as Demonstrated in the VALOR II Trial

TCT-127 The Impact of Later Generation Thoracic Aortic Stent Grafts as Demonstrated in the VALOR II Trial

Two cases of misaligned deployment of Valiant Captivia thoracic stent graft

Thoracic aortic stent grafts have been widely used. We report two cases of proximal misaligned deployment of the Valiant Captivia stent graft after hybrid treatment of thoracic aneurysms. This complication has, to our knowledge, never been previously reported in the literature with this stent graft. We discuss the various factors that may explain this complication. We also describe the bailout technique that was carried out.

An Easy and Useful Exposure Technique Using a Malleable Ring for the Distal Anastomosis in Total Arch Replacement

Even if the thoracic endovascular aortic repair or open stent grafting technique becomes popular, surgical total arch replacement is still important and will continue to be necessary. Distal anastomosis of total arch replacement is critical in this procedure. This article describes an easy and useful method for using a malleable retractor ring in the distal anastomosis of the total arch replacement.

Late Pseudocoarctation Syndrome After Stent-Graft Implantation For Traumatic Aortic Rupture

The present observation illustrates an unusual complication occurring after stent-grafting (S-graft) for aortic isthmus rupture. A 22-year-old patient, treated by S-graft in the emergency department for traumatic aortic rupture, was readmitted 10 months later with pseudocoarctation syndrome. A membrane was found inside the stent-graft that had induced a pseudo-dissection, which caused the pseudocoarctation syndrome. Surgical treatment consisted of removing the stent-graft and membrane and replacing it with a vascular implant. The patient's clinical course was fair. The suggested mechanism was circumferential neoendothelialization of the stent-graft. Dehiscence caused the superior part of the membrane to drop into the lumen of the stent-graft creating a "false channel" that compressed the "true lumen" and induced "pseudocoarctation" syndrome. The cause of the extensive neointimalization remains unexplained. Thoracic aortic stent-grafts require regular follow-up monitoring by angioscan or angio-magnetic resonance imaging.

Transesophageal Echocardiography Guidance for Stent-Graft Repair of a Thoracic Aneurysm is Facilitated by the Ability of Partial Stent Deployment

Transesophageal echocardiography (TEE) is routinely used in our Institution for monitoring correct positioning of thoracic aortic stent grafts. We present a case of successful endovascular repair of three discrete thoracic aortic aneurysms with Zenith TX2 endovascular stent grafts in an 82-year-old female patient. Our focus is on the increased value of TEE guidance because of the ability of partial stent deployment and manipulation during insertion.

Magnetic Navigation for Thoracic Aortic Stent-graft Deployment Using Ultrasound Image Guidance

We propose a system for thoracic aortic stent-graft deployment that employs a magnetic tracking system (MTS) and intraoperative ultrasound (US). A preoperative plan is first performed using a general public utilities-accelerated cardiac modeling method to determine the target position of the stent-graft. During the surgery, an MTS is employed to track sensors embedded in the catheter, cannula, and the US probe, while a fiducial landmark based registration is used to map the patient's coordinate to the image coordinate. The surgical target is tracked in real time via a calibrated intraoperative US image. Under the guidance of the MTS integrated with the real-time US images, the stent-graft can be deployed to the target position without the use of ionizing radiation. This navigation approach was validated using both phantom and animal studies. In the phantom study, we demonstrate a US calibration accuracy of 1.5 ± 0.47 mm, and a deployment error of 1.4 ± 0.16 mm. In the animal study, we performed experiments on five porcine subjects and recorded fiducial, target, and deployment errors of 2.5 ± 0.32, 4.2 ± 0.78, and 2.43 ± 0.69 mm, respectively. These results demonstrate that delivery and deployment of thoracic stent-graft under MTS-guided navigation using US imaging is feasible and appropriate for clinical application.

Invited Commentary

Invited Commentary

Experience with Thoracic Aortic Stent-Grafting at the Royal Brisbane and Women’s Hospital: Outcomes from the First Decade

Objectives: To describe thoracic endovascular aortic repair (TEVAR) outcomes at the Royal Brisbane and Women’s Hospital between 2001-2010. Design: Prospective cohort study. Results: We successfully treated 95 of 97 patients for a 98% procedural success rate. Of the treated patients, 68 (72%) were males and mean age was 61 ± 17 years. Average follow up was 3.6 ± 2.0 years. Pathologies treated were: dissection (n = 35), aneurysmal disease (n = 32), traumatic disease (n = 19), coarctation (n = 5) and miscellaneous (n = 4). There was one peri-procedural myocardial infarction. Renal complications occurred in 7 patients (3 with doubling creatinine and 4 requiring temporary renal replacement therapy). Stroke occurred in 2 patients and paresis in 2 patients (permanent in one). Six patients died during index hospitalization and 17 deaths occurred during follow-up, 2 of which were confirmed secondary to aortic pathology. Age (HR 1.08 per year, p < 0.01) and ASA class (HR 2.2 per class, p = 0.02) were independently associated with mortality. There were 25 re-interventions in 22 patients. Eighteen of these re-interventions in 16 patients were related to the management of complications of TEVAR of which 13 were for endoleaks; eight type I, four type II, one type III. Conclusion: TEVAR can be used to treat thoracic aortic pathology but questions remain regarding long-term durability.

Hybrid Approaches to Complex Aortic Arch Aneurysms

The management of aortic arch aneurysms remains a clinical challenge. Although open operative techniques have been refined with improving results over the last 2 decades, neurologic and cardiovascular complications remain significant causes of morbidity and mortality. This is related to the requirement for hypothermic circulatory arrest with adjunct cerebral perfusion strategies during open aortic arch surgery. In patients thought to be at prohibitively high risk for conventional repair, an alternative therapy is much desired. The recent introduction of thoracic aortic endovascular stent grafting (TEVAR) has provided an alternative surgical option in patients felt to be at prohibitively high risk for conventional open aortic arch repair. Combining conventionalsurgicaltechniqueswithendovasculartechnology,this so-called “hybrid” aortic arch repair seeks to minimize the “operation” by either eliminating or significantly simplifying and shortening the arch reconstruction, thus limiting the duration of circulatory arrest and cerebral ischemia. The arch hybrid repair is a landing zone “0” endovascular repair of the aortic arch and is guided by the 2 following fundamental concepts: (1) brachiocephalic bypass, or revascularization of the great vessels; (2) construction of optimal proximal and distallandingzonesforTEVAR.Therefore,archhybridrepair comprises open surgical techniques for great vessel revascularization and landing zone reconstruction along with endovascular stent grafting performed concomitantly or at a later time. The arch hybrid repair is especially appealing in older patients and in those with significant comorbidities who may not tolerate prolonged cardiopulmonary bypass and circulatory arrest. This report focuses on aortic arch hybrid operative techniques.

The Modified Chimney Technique With a Thoracic Aortic Stent Graft to Preserve the Blood Flow of the Left Common Carotid Artery for Treating Descending Thoracic Aortic Aneurysm and Dissection

While thoracic endovascular aortic repair is an effective treatment option for descending thoracic aorta pathology, it does have limitations. The main limitation is related to the anatomical difficulties when disease involves the aortic arch. A fenestrated, branched aortic stent graft and hybrid operation has been introduced to overcome this limitation, but it is a custom-made device and is time consuming to manufacture. Furthermore, these devices cannot be used in an emergency setting. We report two patients with massive descending thoracic aortic aneurysm and ruptured aortic dissection very near the aortic arch who underwent a procedure which we named the modified chimney technique. The modified chimney technique can be used as a treatment option in such an emergency situation or as a rescue procedure when aortic pathology is involved near the supra-aortic vessels.

Long-Term Survival After Open Repair and Thoracic Endovascular Aortic Repair for Descending Thoracic Aortic Aneurysms

Thoracic endovascular aortic repair (TEVAR) for descending thoracic aortic aneurysms (DTAs) was first reported by Dake et al1 in 1994. The advent of TEVAR was clinically relevant because open DTA repair had long been associated with operative mortality rates ranging from ≈5% to 7% at centers of excellence2,3 to as high as 20% to 22% in real-world practice.4,5 The favorable results6 of TEVAR with nearly 75% reduction in operative mortality in early industry-sponsored device trials led to US Food and Drug Administration approval for first commercial use in 2005 and subsequent device approvals in 2008.7,8 The operative mortality and morbidity benefits of TEVAR highlighted by numerous single-center reports,9–11 device registries,12,13 and device trials6–8 have led to widespread public and surgeon acceptance of this less invasive modality for the management of DTA in contemporary practice. As such, TEVAR has supplanted open surgical repair in the majority of patients with DTA.14,15 Article see p 2661 In the current issue of Circulation , Goodney et al16 reviewed the long-term survival of patients treated for DTA by the use …

Modified and “Reverse” Frozen Elephant Trunk Repairs for Extensive Disease and Complications After Stent Grafting

The frozen elephant trunk (FET) repair technique combines conventional arch repair with the patient under circulatory arrest with stent grafting and is increasingly being used to treat extensive thoracic aortic disease. This surgical approach is evolving, including its use for complications after thoracic aortic stent grafting - the so-called reversed frozen elephant trunk (RFET). We evaluated the safety and efficacy of FET and RFET operations in high-risk patients. Between July 2001 and December 2010, 31 patients underwent FET and 19 patients underwent RFET for extensive thoracic aortic disease. Causes included aneurysm (n=32), acute dissection (n=17), and rupture (n=1). Twenty-three cases (46%) were for urgent or emergency indications. Patient data and outcomes were collected through a prospectively maintained clinical database and 3-dimensional analysis of computed tomography (CT) scans. Outcomes were assessed using Kaplan-Meier methodology. In-hospital mortality was 8% (n=4, including 1 emergency RFET procedure for aortic rupture and 2 urgent FET procedures for symptomatic degenerative aneurysm). Stroke occurred in 5 patients (10%) and spinal cord injury in 4 patients (8%). Mean hospital stay was 14.3 days (range 4 to 67 days). Five endoleaks were observed (4 type II, 1 type I) requiring 2 endovascular reinterventions. Mean follow-up was 17 months (range, 1 to 76 months) and actuarial survival was 87% at 2 years. Frozen elephant trunk repair is an effective surgical strategy for managing high-risk patients with extensive pathologic conditions of the thoracic aorta. The RFET approach is a feasible option for proximal aortic complications after previous descending stent grafting. Intermediate outcomes are reasonable for both approaches and further evaluation of these techniques is warranted.

Volumetric analysis of type B aortic dissections treated with thoracic endovascular aortic repair

Type B aortic dissections are being successfully treated by thoracic endovascular aortic repair (TEVAR). Postoperative false lumen patency has been associated with aneurysmal dilatation and rupture of the thoracic aorta, necessitating further intervention. This is the first volumetric analysis of type B aortic dissections comparing patients with and without false lumen thrombosis (FLT) after TEVAR. We hypothesized that a greater increase in postoperative true lumen volume will lead to FLT, and without this change, false lumen patency will result. Preoperative and postoperative computed tomography angiography (CTA) imaging was analyzed using three-dimensional reconstruction to measure the short- and long-axis diameter and cross-sectional area of the true lumen, false lumen, and total aorta. Measurements were taken at 5-cm intervals from the left subclavian artery to the aortic bifurcation. Pre- and postoperative volumetric data were calculated and compared in patients with and without postoperative FLT. Between 2006 and 2010, 132 patients underwent thoracic aortic stent grafting. Of these, 31 (23%) had thoracic endografting for type B aortic dissection. Pre- and postoperative CTA images were available for analysis in 23 patients with a mean age of 59 ± 14 years treated for acute, complicated (n = 8, 35%), and chronic (n = 15, 65%) indications. Mean follow-up imaging was 9 months (range, 1-39 months). Thirteen patients (56%) had postoperative FLT and 10 (43%) had persistent false lumen patency. The dissections involved the left subclavian artery (n = 12), visceral arteries (n = 14), renal arteries (n = 16), and iliac arteries (n = 15). The left subclavian artery was intentionally covered in 15 patients (65%). There were no significant differences in age, acute vs chronic dissection, branch vessel involvement, coverage of the left subclavian artery, or distal extent of the endograft between patients with and without postoperative FLT. Patients with postoperative FLT had a significantly smaller preoperative maximum thoracic aortic diameter (5.05 ± 1.0 vs 6.30 ± 1.4 cm; P = .02). Volumetric analysis demonstrated significantly smaller preoperative true lumen volume (141.3 ± 68 vs 230.5 ± 92 cm(3); P = .01) in patients with FLT, but no difference in preoperative false lumen volume. Patients with FLT had a significant increase in the volume percentage of the true lumen from 42.7% to 61.7% (P = .02) after stent graft repair, compared with an increase from 46.7% to 47.7% (P = .75) in patients with persistent false lumen patency. This volumetric study of type B aortic dissection treated with TEVAR suggests that the ability of the endograft to significantly increase the true lumen volume as a percent of the total aorta most accurately predicts postoperative FLT. This is best demonstrated in a nonaneurysmal dissection regardless of timing since dissection.

Thoracic endovascular aortic repair: Evolution of therapy, patterns of use, and results in a 10-year experience

The introduction of aortic stent grafting in the treatment of thoracic aortic disease has pioneered unique treatment options and gained rapid clinical adoption despite a paucity of long-term outcome data. The purpose of this analysis is to examine all operations performed using thoracic aortic stent grafts at the University of Pennsylvania Health System. A total of 502 operations involving thoracic aortic stent grafting were performed between April 1999 and April 2009. Patients were followed in a prospectively collected clinical perioperative registry, and long-term outcomes were determined from administrative data sources. Aortic pathologies included aortic aneurysm, acute aortic dissection (types A and B), hybrid arch repairs, reinterventions with additional stents, pseudoaneurysm, chronic type B dissection, traumatic transection, penetrating aortic ulcer, and other unique indications. Patients' mean age at the time of thoracic endovascular aortic repair was 70.1 ± 12.4 years, and 51% of the patients were aged more than 70 years. Some 41% of patients were female, and the majority of patients (87%) were hypertensive. Overall 30-day mortality was 10.1%. Multivariable risk factors for 30-day mortality included urgent/emergency, Stanford type A aortic dissection, perioperative spinal ischemia, type C aortic coverage, hybrid arch operation, aortic transection, chronic renal failure, and age. Neurologic complications included permanent complete or incomplete paraplegia in 17 patients (3.4%), reversible spinal cord ischemia in 26 patients (5.1%), transient stroke in 16 patients (3.2%), and permanent stroke in 23 patients (4.6%). Greater extent of aortic coverage was not associated with risk of spinal cord ischemia. Access complications, stroke, and endoleaks diminished with increased operative experience over time. Risk factors for late mortality included urgent/emergency indications, hybrid procedures, traumatic aortic transection, age, perioperative paralysis, and chronic renal failure. Patients undergoing stent grafting for type B dissection were more likely to survive than patients undergoing stent grafting for aneurysms or other indications. Thoracic aortic stent grafting has evolved to be a viable option to complement, augment, or even replace traditional treatments for aortic disease. These data illustrate the applicability of this evolving technology in the establishment of new treatment paradigms for complex aortic pathologies.

‘‘Relining’’ of Thoracic Aortic Stent Grafts for Patients Presenting With Rupture/Impending Rupture

To report a series of patients following thoracic endovascular aortic repair (TEVAR) presenting with rupture, who were effectively treated with TEVAR relining. Five patients who underwent repeat TEVAR in an urgent fashion were identified. Chart review was performed to identify demographics, device type, aneurysm characteristics, and postoperative course. Mean time to relining procedure was 5.8 (range 2-10) years. All patients had ≥3 device components originally placed. Mean size of the original aneurysm was 7.2 cm (range 6.6-8). All patients underwent relining with proximal and distal extension with immediate technical success. At a mean follow-up of 1.3 years, there was no evidence of endoleak and no patients required repeat intervention. Complete relining with proximal and distal extension was effective in treating patients presenting with rupture. These findings suggest that proximal and distal landing zones provided, relining should be considered the initial management strategy in patients s/p TEVAR re-presenting with rupture.

Endovascular Stent Grafts in Urgent Blunt and Penetrating Thoracic Aortic Trauma

A traumatic thoracic aortic injury is fatal in the majority of cases. Surviving the aortic injury in addition to the myriad of associated trauma requires comprehensive medical management from many medical services. Balancing these services and coordinating the medical care requires free and open communication between services. Although one might assume a thoracic aortic injury takes precedence over other injuries, an organized plan of care in which the morbidity of the injury as well as the consequences of treatment of each injury helps provide an appropriate "rank order" in the treatment process. A patient with a thoracic aortic injury can be observed for several days while additional injuries are treated, as long as appropriate blood pressure controls are observed. The treatment order for multiple injuries must be reevaluated on a regular basis to adjust for changes in the overall clinical condition. This rank order to treatment and scheduled treatment plan allows for appropriate imaging, evaluation, and coordination of services in preparation for the placement of a thoracic aortic stent graft. The goal of treatment is to reduce the risk of aortic rupture and subsequent fatal hemorrhage. Choosing an open surgical repair versus an endovascular stent graft depends upon physician expertise and clinical status of the patient. In the appropriate clinical setting, endovascular repair of the thoracic aortic injury has become the treatment of choice at the authors' institution in patients with significant operative risks and extensive comorbid injuries. Specific characteristics of the injured aorta also dictate the type of endovascular device required for repair. Case reviews of a patient with blunt trauma and a patient with penetrating trauma used to demonstrate clinical parameters, imaging options, and details of stent graft choice and placement, are presented followed by a review of the literature.