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

EXTENT study: Medium-term outcomes of EXTra-design engineering inner-branch ENdografts for the treatment of complex aortic aneurysms from a multicenter collaboration

OBJECTIVE

This study aims to present the medium-term outcomes of Extra-Design engineering endografts with inner branches (EDE-iBEVARs, Artivion) in endovascular aortic repairs of complex aneurysms building upon promising early results.

METHODS

A retrospective, international, multi-center study was conducted including consecutive patients who underwent complex endovascular aortic repairs using EDE-iBEVARs between 2018 and 2022. Patient demographics, aneurysm anatomical features, procedural details, reinterventions, complications, and endograft failures during follow-up were assessed. The primary outcome was aneurysm-related mortality. Secondary outcome measures included the freedom from all-cause mortality and reintervention, technical and clinical success, and late related complications including branch instability, endoleaks, and serious adverse events.

RESULTS

Our study encompassed a total of 260 patients across 13 European centers. The cohort included patients with thoracoabdominal aortic aneurysms (n = 116), suprarenal or juxta-renal aneurysms (n = 95), and those who had previous open repair or previous endovascular aortic repair with type 1A endoleak (n = 49). Of 982 possible inner branches (937 antegrade and 45 retrograde), 962 (98%) were successfully cannulated and bridged with covered stents during the index procedure. Overall, the endograft was successfully deployed in 98% of patients, and 93% were discharged from hospital following surgery. At 3 years, freedom from aneurysm-related mortality was 97%, whereas the freedom of all-cause mortality was 89%. Freedom from reinterventions was 91% and 76% at 1 and 3 years, respectively. The rate of late complications such as endoleaks or branch instability events was 12% (n = 30). The late branch occlusion rate during follow-up was 1.5% (n = 15), of which 12 were renal branches.

CONCLUSIONS

EDE-iBEVARs demonstrate satisfactory medium-term outcomes with reintervention rates comparable to other endografts. Encouragingly, rates of branch patency were high, and major adverse events were low. This technology could expand the treatment options for patients with challenging complex aortic conditions.

Palliative Repair of a Mycotic Aortic Arch Pseudoaneurysm With a Physician-Modified Endograft and In-Situ Laser Fenestration

PURPOSE

Open aortic arch repair is the gold standard in the treatment of diseases involving the ascending aorta and aortic arch. However, due to the invasive nature of open repair, high-risk patients with multiple comorbidities are often not suitable candidates for open surgical repair. While endovascular aortic repair is far less invasive, endovascular arch repair remains a difficult challenge due to the aortic arch diameter and angulation, origin of the supra-aortic arteries, and the lack of commercially available thoracic branched devices in the United States.

CASE REPORT

Here we describe palliation of a mycotic aortic arch pseudoaneurysm with a physician-modified endograft and in situ laser fenestration. Our technique allowed for rapid repair of the pseudoaneurysm with minimal physiologic disturbances and no perioperative complications in a high-risk surgical patient.

CONCLUSION

Physician-modified endografts are feasible and may be an effective treatment option for palliation of acute aortic arch lesions in high-risk surgical patients.

Performance of Viabahn balloon-expandable stent compared with self-expandable covered stents for branched endovascular aortic repair

OBJECTIVE

The objective of this study was to compare the performance between the Viabahn balloon-expandable stent (VBX; Viabahn [W. L. Gore & Associates, Flagstaff, Ariz]) and a covered self-expandable stent (SES; Fluency [Bard Peripheral Vascular, Tempe, Ariz]) used as bridging stents for directional branches during fenestrated or branched endovascular aneurysm repair of complex aortic aneurysms.

METHODS

Patients with thoracoabdominal aortic aneurysms (type I-IV) or pararenal aortic aneurysms either at high risk for open repair or unsuitable for endovascular repair with commercially available devices were prospectively enrolled in a physician-sponsored investigational device exemption trial. Descriptive statistics of the cohort included demographics, risk factors, and anatomic and device characteristics. Individual branches were grouped as either VBX or SES and had data analyzed for primary patency, branch-related type I or type III endoleaks, branch instability, branch-related secondary intervention, and branch-related aortic rupture or death. Categorical variables were expressed as total and percentage, and continuous variables were expressed as median (interquartile range). Kaplan-Meier curves were used to estimate long-term results. Groups were compared with the log-rank test. P value <.05 was considered statistically significant.

RESULTS

During the period from July 2012 through June 2019, there were 263 patients treated for complex aortic aneurysm (thoracoabdominal aortic aneurysm) with fenestrated or branched endografts. The devices used were either custom-manufactured devices or off-the-shelf p-Branch or t-Branch (Cook Medical, Bloomington, Ind) devices. The median age was 71 years (interquartile range, 66-79 years); 70% were male, and 81% were white. The most common cardiac risk factors were smoking (92%), hypertension (91%), hyperlipidemia (78%), and chronic obstructive pulmonary disease (52%). The total number of vessels incorporated into the repair was 977, with branches representing 18.4% (179 branches). Among these 179 branches, the celiac artery, superior mesenteric artery, right renal artery, and left renal artery received 54 (30%), 56 (31%), 38 (21%), and 31 (18%) branches, respectively. VBX and SES groups represented 96 (54%) and 81 (46%) of the branches implanted. The celiac artery, superior mesenteric artery, right renal artery, and left renal artery received VBX as a bridging stent in 40%, 46.7%, 33.8%, and 32.2% respectively. The overall cohort survival rate was 78.5% at 24 months. There was no branch-related rupture or mortality. Primary patency at 24 months (VBX, 98.1%; SES, 98.6%; log-rank, P = .95), freedom from endoleak (VBX, 95.6%; SES, 98.6%; log-rank, P = .66), freedom from secondary intervention (VBX, 94.7%; SES, 98.1%; log-rank, P = .33), and freedom from branch instability (VBX, 95.6%; SES, 97.2%; log-rank, P = .77) were similar between groups.

CONCLUSIONS

This initial experience with VBX stents demonstrated excellent primary patency and similarly low rates of branch-related complications and endoleaks, with no branch-related aortic rupture or death. Our results demonstrate that in a high-volume, experienced aortic center, the VBX stent is a safe and effective bridging stent option during branched endovascular aortic repair. Multicenter studies with a larger cohort and longer follow-up are necessary to validate these findings.

Single-center experience with an inner branched arch endograft

OBJECTIVE

Whereas open repair is the "gold standard" for most aortic arch diseases, a subgroup of patients might benefit from an endovascular approach. The introduction of branched stent grafts with dedicated design to address the challenges of the ascending aorta and the aortic arch has opened an entirely new area of treatment for these patients. We investigated the early outcomes of branched thoracic endovascular aortic repair (b-TEVAR) in various types of disease of the aortic arch.

METHODS

A retrospective analysis was conducted of prospectively collected data from a single center of all consecutive patients treated with b-TEVAR. The indication for elective endovascular repair was consented in an interdisciplinary case conference. All patients were treated with a custom-made inner branched arch endograft with two internal branches (Cook Medical, Bloomington, Ind) and left-sided carotid-subclavian bypass. Study end points were technical success, 30-day mortality, and complications as well as late complications and reinterventions.

RESULTS

Between 2012 and 2017, there were 54 patients (38 male; median age, 71 years) treated with diseases of the aortic arch. Indications for therapy involved degenerative aortic arch or proximal descending aortic aneurysms requiring arch repair (n = 24), dissection with or without false lumen aneurysms (n = 26), and penetrating aortic ulcers (n = 4). Forty-three cases (80%) were performed electively and 11 urgently for contained ruptures (n = 3) or symptomatic aneurysms (n = 8) with endografts already available for the patient or with grafts of other patients with similar anatomy. Technical success was achieved in 53 cases (98%). The 30-day mortality and major stroke incidence were 5.5% (3/54) and 5.5% (3/54), respectively; in-hospital mortality was 7.4% (n = 4), and minor strokes (including asymptomatic new cerebral lesions) occurred in 5.5% (n = 3). There were two cases of transient spinal cord ischemia with complete recovery and one of paraplegia. No retrograde type A dissections or cardiac injuries were observed. Three early stent graft-related reinterventions were necessary to correct proximal endograft kinking with type IA endoleak in one patient, a bridging stent graft stenosis in another patient, and false lumen persistent perfusion from dissected supra-aortic vessels in the last patient. Mean in-hospital stay was 14 ± 8 days. During a mean follow-up of 12 ± 9 months, three nonaorta-related deaths and one aorta-related death distal to the arch repair were observed.

CONCLUSIONS

Treatment of aortic arch diseases with b-TEVAR is feasible and safe with acceptable mortality and stroke rates.

Techniques for Preserving Vertebral Artery Perfusion During Thoracic Aortic Stent Grafting Requiring Aortic Arch Landing

Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

Hybrid Strategy for Residual Arch and Thoracic Aortic Dissection following Acute Type A Aortic Dissection Repair

Progressive dilatation of the false lumen in the arch and descending aorta has been encountered in one-third of survivors as a late sequelae following repair of ascending aortic dissection. Conventional treatment for the same requiring cardiopulmonary bypass and deep hypothermic circulatory arrest is associated with high morbidity and mortality especially in the elderly cohort of patients. Herein we report a case of symptomatic progressive aneurysmal dilatation of residual arch and descending thoracic aortic dissection following repair of type A aortic dissection, successfully treated by total arch debranching and ascending aortic prosthesis to bicarotid and left subclavian bypass followed by staged retrograde aortic stent-graft deployment. This case report with relevant review of the literature highlights this clinical entity and the present evidence on its appropriate management strategies. Close surveillance is mandatory following surgical repair of type A aortic dissection and hybrid endovascular procedures seem to be the most dependable modality for salvage of patients detected to have progression of residual arch dissection.

The golden age of minimally invasive cardiothoracic surgery: current and future perspectives

Over the past decade, minimally invasive cardiothoracic surgery (MICS) has grown in popularity. This growth has been driven, in part, by a desire to translate many of the observed benefits of minimal access surgery, such as decreased pain and reduced surgical trauma, to the cardiac surgical arena. Initial enthusiasm for MICS was tempered by concerns over reduced surgical exposure in highly complex operations and the potential for prolonged operative times and patient safety. With innovations in perfusion techniques, refinement of transthoracic echocardiography and the development of specialized surgical instruments and robotic technology, cardiac surgery was provided with the necessary tools to progress to less invasive approaches. However, much of the early literature on MICS focused on technical reports or small case series. The safety and feasibility of MICS have been demonstrated, yet questions remain regarding the relative efficacy of MICS over traditional sternotomy approaches. Recently, there has been a growth in the body of published literature on MICS long-term outcomes, with most reports suggesting that major cardiac operations that have traditionally been performed through a median sternotomy can be performed through a variety of minimally invasive approaches with equivalent safety and durability. In this article, we examine the technological advancements that have made MICS possible and provide an update on the major areas of cardiac surgery where MICS has demonstrated the most growth, with consideration of current and future directions.

Hybrid endovascular repair in aortic arch pathologies: a retrospective study

The aortic arch presents specific challenges to endovascular repair. Hybrid repair is increasingly evolving as an alternative option for selected patients, and promising initial results have been reported. The aim of this study was to introduce our experiences and evaluate mid-term results of supra aortic transpositions for extended endovascular repair of aortic arch pathologies. From December 2002 to January 2008, 25 patients with thoracic aortic aneurysms and dissections involving the aortic arch were treated with hybrid endovascular treatment in our center. Of the 25 cases, 14 were atherosclerotic thoracic aortic aneurysms and 11 were thoracic aortic dissection. The hybrid repair method included total-arch transpositions (15 cases) or hemi-arch transpositions (10 cases), and endovascular procedures. All hybrid endovascular procedures were completed successfully. Three early residual type-I endoleaks and one type-II endoleak were observed. Stroke occurred in three patients (8%) during the in-hospital stage. The perioperative mortality rate was 4%; one patients died post-operatively from catheter related complications. The average follow-up period was 15 ± 5.8 months (range, 1–41 months). The overall crude survival rate at 15 months was 92% (23/25). During follow-up, new late endoleaks and stent-raft related complications were not observed. One case (4%) developed a unilateral lower limb deficit at 17 days and was readmitted to hospital. In conclusion, the results are encouraging for endovascular aortic arch repair in combination with supra-aortic transposition in high risk cases. Aortic endografting offers good mid-term results. Mid-term results of the hybrid approach in elderly patients with aortic arch pathologies are satisfying.

Endovascular device design in the future: transformation from trial and error to computational design

Endovascular devices have been designed by trial and error, with bench and animal testing followed by human clinical trials to determine whether the devices are safe and effective. Despite remarkable advances over the past 15 years, there are persistent concerns regarding the long-term durability of endovascular devices. This may be due to deficiencies in device design, which has lagged behind other industries in adopting computational methods that are now routinely used to design, develop, and test new aircraft and automobiles. Similar computational design and failure mode simulations that evaluate performance under stress conditions have not been widely applied in the development of endovascular devices. Advances in medical imaging and computational modeling now allow simulation of physiological conditions in patient-specific 3-dimensional vascular models, which can provide a framework to design and test the next generation of endovascular devices. This modeling will allow the prospective design of devices that can withstand the force variations in the cardiovascular system that occur during bending, coughing, and varying degrees of exercise, as well as the extremes encountered during sudden impact in contact sports. Utilization of computational design methodology that takes into consideration the physiology of the cardiovascular system will improve future endovascular devices so that they are safer and more effective and durable.

The arch and beyond: bare stents in the ascending aorta

PURPOSE

To describe the management of complications from an unsuccessful hybrid repair of an aortic arch aneurysm.

CASE REPORT

A 63-year-old man with acute type B dissection and retrograde dissection into the aortic arch underwent emergent hybrid repair, with partial debranching (ascending aorta to left carotid artery bypass) and proximal stent-graft deployment. At 3 months, computed tomography (CT) showed stent-graft migration, causing a large type I endoleak; flow through the patent left subclavian artery (LSA) caused a large type II endoleak. At a second operation, a bilateral subclavian-to-carotid transposition was performed; the LSA was ligated and a Zenith TX2 thoracic endograft was deployed to seal the leak. Recurrent type I endoleak a year later prompted the final endovascular solution: total supra-aortic vessel debranching, proximal stent-graft deployment, and the unprecedented use of bare Z stents in the ascending aorta. CT at 18 months confirmed stable stent-graft position and no endoleak.

CONCLUSION

Based on this initial experience, bare Z stents can be used to enhance proximal aortic stent-graft fixation and accommodation within the aortic arch.

Stent-grafting of the thoracic aorta by the cardiothoracic surgeon

BACKGROUND

We evaluated endovascular stent-grafting as a new technique in aortic surgery.

METHODS

One hundred ninety-six stent-grafts were implanted in the thoracic aorta in 172 patients. All procedures but one were performed in the operating room by a team of cardiothoracic surgeons; 112 operations (57%) were emergency procedures. Twenty-four procedures (12%) were reoperations for endoleaks. The left subclavian artery origin was covered in 46 cases and the left common carotid artery in 2 cases. Access was by femoral cut-down in 174 procedures, percutaneous femoral approach in 1, and by conduit to the iliac arteries or infrarenal aorta in 17. Surgical reconstruction of damaged access vessels became necessary in 10 cases.

RESULTS

Thirty-day mortality was 9.7% (19 patients). Paraplegia occurred in 1.0% (2 patients). Primary technical success was 85.2%, secondary 91.8%. Six conversions to open repair were necessary, 3 during the procedures and 3 secondarily before discharge. Actuarial survival was 79% at 1 year, 67% at 3 years, and 55% at 5 years.

CONCLUSIONS

The results are excellent, taking into account the high incidence of emergency procedures and that open surgery is not promising in many patients. The cardiothoracic surgeon can perform the procedure after adequate training in endovascular techniques. Surgical skills are mandatory because of the potential need for extended surgical approach to the access vessels or immediate conversion to open surgery. Therefore, the operating room is the preferred site for this procedure.

Great Vessel Management for Endovascular Exclusion of Aortic Arch Aneurysms and Dissections

OBJECTIVES

To evaluate a recent approach for the endovascular repair of thoracic aortic aneurysms and dissections involving the aortic arch in high risk patients (HRP).

METHODS

Amongst 102 thoracic aortic aneurysms and dissections, we treated 25 patients for aortic arch endovascular exclusion after transposition of the great vessels, of which 14 (56%) had thoracic aortic arch aneurysms and 11 type A and B chronic aortic dissections. Total transpositions were done in 15 cases (60%) and hemi-arch transpositions in 10. We then used Talent, Excluder and Zenith endografts in 12, seven and six cases, respectively.

RESULTS

Surgical transpositions were complicated by one minor stroke, which worsened to a major stroke (4%) after endovascular exclusion. After endovascular exclusions, two patients (8%) died from catheterization related complications. One patient had a delayed minor stroke (4%). The successful exclusion rate was 92%. During follow-up (15+/-5.8 months), one patient (4%) developed unilateral limb palsy, successfully treated by CSF drainage. The late exclusion rate remained 92%. No stent-related complications were seen.

CONCLUSIONS

Transposition of supra-aortic vessels allows the endovascular exclusion of the aortic arch in HRP. Aortic endografting after surgical transposition proved to be feasible and offers good mid-term results. Specialized surgical centers with both endovascular and surgical expertise are required to treat these patients.

Surgical Correction of Ascending Type A Thoracic Aortic Dissection: Simultaneous Endoluminal Exclusion of the Arch and Distal Aorta

PURPOSE

To describe repair of an ascending type A dissection combining an open ascending tube graft with simultaneous great vessel transposition and antegrade deployment of an endoluminal graft across the arch and into the descending thoracic aorta.

CASE REPORT

A 50-year-old man was evaluated at an outside hospital and transferred to our service for treatment of an ascending aortic dissection with associated lower extremity ischemia. Imaging identified an aortic dissection extending from the aortic root to the aortic bifurcation and into the right common iliac artery. A hybrid procedure incorporating both open and endovascular techniques successfully repaired the dissection and aneurysm and restored blood flow to the extremity.

CONCLUSIONS

Although less invasive procedures are sometimes appropriate for repair in the descending thoracic aorta, surgical correction of an ascending dissection and endoluminal exclusion of the arch and distal aorta may form the basis of future treatment strategies for complex aortic pathologies, possibly eliminating the need for hypothermic cardiac arrest.

Endovascular Treatment of Aortic Arch Aneurysms

INTRODUCTION

The aim of this study was to review our clinical experience with endovascular treatment of aortic arch aneurysms using different commercially available grafts (Gore, Talent, Endomed, Cook).

METHODS

From 1999 to 2004, 97 patients received endovascular treatment for diseases of the thoracic aorta. In 30 cases (26 males, 4 females) the aortic arch was involved. The left subclavian artery was overstented (Ishimaru zone '2') in 18 cases (60%). Only in the first three cases had the subclavian artery been revascularized. The left common and subclavian arteries were covered (zone '1') in 6 (20%) cases-all had the carotid artery reconstructed, either simultaneously (five cases) or as a staged procedure (one case). Finally, the whole aortic arch was over-stented (zone '0') in 6 (20%) cases, with simultaneous (five cases) or staged (one case) grafting of the supra-aortic vessels from the ascending aorta.

RESULTS

Perioperative mortality was 2/30 (7%), due to graft migration (zone '2') and intra-operative stroke (zone '0'), respectively. One minor stroke was observed. No cases of paraplegia were recorded. Three type I endoleaks were observed. Two resolved at 6 months follow-up; one zone '0' graft is still being followed. There was one surgical conversion for endograft failure 2 weeks after implantation. Thus, the technical success rate was 87% (26/30) cases. The mean follow-up time was 23+/-17 months. No new onset endoleaks or aneurysm-related deaths were recorded.

CONCLUSIONS

Currently available grafts may be deployed in the aortic arch in most instances. De-branching of the aortic arch with surgical revascularization for zone '0' and '1' seems to be adequate to obtain a satisfactory proximal landing zone.