Endovascular Repair of the Descending Aorta
Ayman Saeyeldin, MD
Young Erben, MD
Mohammad A. Zafar, MD
Afsha Aurshina, MBBS
Camilo A. Velasquez, MD
Wei-Guo Ma, MD
Chandni Patel, MD
Jeremy D. Asnes, MD
Bulat Ziganshin, MD, PhD
John A. Elefteriades, MD, PhD (hon)
Bauer E. Sumpio, MD, PhD
Key Points
TEVAR is a safe and effective method for treatment of various pathologies affecting the descending thoracic aorta.
Various devices are currently FDA approved for TEVAR, with growing evidence supporting their safety and efficacy.
Careful preoperative planning is indispensable in order to choose the correct stent type and minimize complications.
Revascularization and debranching procedures (hybrid repair) should be considered on an individualized basis.
Endovascular treatment has less perioperative morbidity and mortality than open repair; however, long-term results regarding the durability and reliability of these devices are scarce.
I. Introduction
Since the preliminary reports on thoracic endovascular aortic repair (TEVAR) in 1994,1 major advancements have been achieved in the stent materials, sizes, conformability, graft tapering, techniques of deployment, and the applications of this life-saving method of treatment. TEVAR has successfully reoriented the current treatment guidelines of descending thoracic aortic aneurysms (DTAs) as TEVAR permits the introduction of a stent graft into the descending or thoracoabdominal aorta through a minimally invasive incision. Although TEVAR was initially introduced for the treatment of degenerative aneurysmal aortic diseases in nonsurgical candidates, TEVAR is now considered a valid treatment option for an array of other aortic pathologies, with the advantages of lower morbidity, avoidance of a thoracotomy incision, and the elimination of the need for partial or total circulatory support. This chapter discusses the endovascular repair of aortic pathologies afflicting the descending thoracic aorta.
II. Anatomic Background
The descending aorta is the longest segment of the thoracic aorta, beginning at the isthmus between the origin of the left subclavian artery and the ligamentum arteriosum and coursing anterior to the vertebral column, giving off paired thoracic arteries (T1-T12), and then traversing the aortic hiatus in the diaphragm into the abdomen to continue as the abdominal aorta. The abdominal aorta extends retroperitoneally to its bifurcation into the common iliac arteries at the level of the fourth lumbar vertebra.
A. Landing Zones For the purpose of describing the extent of endovascular coverage, the thoracic aorta is divided into landing zones,2 which determine the location of the stent and define the need for a concomitant debranching procedure (Fig. 6.1):
Zone 0: Proximal to the takeoff of the innominate artery
Zone 1: Distal to the innominate artery, but proximal to the origin of the left common carotid artery
FIGURE 6.1: Zones of attachment. Reprinted with permission from Fillinger MF, Greenberg RK, McKinsey JF, Chaikof EL. Society for Vascular Surgery Ad Hoc Committee on TRS. Reporting standards for thoracic endovascular aortic repair (TEVAR). J Vasc Surg. 2010 52:1022-1033, 1033. e1015.
Zone 2: Distal to the origin of the left common carotid artery, but proximal to the left subclavian artery
Zone 3: ≤2 cm from the left subclavian artery without covering it
Zone 4: >2 cm distal to the left subclavian, but within the proximal half of the descending aorta (T6)
Zone 5: Starts in the distal half of the descending thoracic aorta, but proximal to the celiac artery
Zone 6: Coeliac origin to the top of the superior mesenteric artery
Zone 7: Superior mesenteric artery origin, suprarenal aorta
Zone 8: Covers at least one renal artery
Zone 9: Infrarenal
Zone 10: Common iliac
Zone 11: External iliac
B. Spinal Perfusion The spinal cord is supplied by branches of the vertebral artery: one anterior spinal artery (supplying the anterior two-thirds of the spinal cord) and two posterior spinal arteries (supplying the posterior one-third), which anastomose distally at the conus medullaris. The thoracic aorta is dependent on radicular contributions to the anterior spinal artery via the artery of Adamkiewicz, which can be found between T9 and T12 in 75% of individuals, and other segmental (intercostal) arteries.3
III. Indications for TEVAR
TEVAR was initially introduced for the treatment of thoracic aortic aneurysms in patients who could not tolerate open repair. Keystone trials led to approval by the United States Food and Drug Administration (FDA) in 2005.4 Since then, TEVAR has been a treatment modality for other aortic pathologies, such as aortic dissection, blunt traumatic aortic injury, and penetrating aortic ulcers.5,6 TEVAR has also expanded its reach beyond the original nonsurgical patients to patients who would also be suitable for open surgery.
A. Thoracic Aortic Aneurysms
1. Patients with large DTAs are at risk of dire complications such as rupture or dissection. The risk of complications increases as the diameter of the descending aorta enlarges, with a “hinge point” at 7 cm.7,8 However, by the time the aorta reaches this size, 43% of patients suffer a devastating complication.9 Survival can be improved with preemptive open surgical repair of the aorta, before these critical diameters are reached.10,11 Although there is a paucity of data comparing endovascular repair to medical management, it is plausible to assume that outcomes would be better with endovascular repair (rather than purely medical management) in patients with indications for open surgical intervention.
2. The current recommendations for TEVAR in patients with degenerative aneurysms of the descending thoracic aorta include aortic size exceeding 5.5 cm, saccular aneurysms, or postoperative pseudoaneurysms (class: Ib).10 TEVAR aims to exclude the aortic aneurysm from the circulation by implanting a membrane-covered stent-graft across the lesion, in order to prevent further enlargement and eventual aortic rupture. In DTAs, it is recommended that stent-graft exceed the reference aortic diameter at the landing zone by at least 10%-15% (to produce a “seal”).
B. Thoracic Aortic Dissection
1. Repair of descending aortic dissection (DescAD) (type B in Stanford classification, or type III in DeBakey classification) is indicated in patients with complications, which typically occur within the first 2 weeks of diagnosis, affecting approximately 25% of patients.10,11,12,13 The suitable complications include the following:
End-organ malperfusion
Refractory pain in spite of optimized medical treatment (OMT)
Rapid expansion if the false lumen (which may be appreciated over the first several months following an acute presentation)
Impending or frank rupture
Aneurysmal dilation in a chronic DescAD meeting criteria for repair
2. TEVAR aims to stabilize the dissected aorta to prevent late complications by inducing favorable aortic remodeling. Obliteration of the intimal tear by implantation of a stent-graft helps redirect blood flow into the true lumen (TL), thus improving distal perfusion.14 At least 1 or 2 cm of dissected aorta must be covered to provide stent fixation. Thrombosis of the false lumen (FL) is also promoted by stent grafting, which induces the beneficial process of aortic remodeling.
3. For uncomplicated DescAD, reports from the International Registry of Acute Aortic Dissection (IRAD) show no benefit of TEVAR over medical therapy.15 For complicated acute DescAD, TEVAR is the treatment of choice.16
4. The INvestigation of STEnt grafts in patients with type B Aortic Dissection (INSTEAD trial),17 which compared TEVAR + OMT with OMT alone in patients with uncomplicated type B AD, has shown no significant difference in the 2-year all-cause mortality, with 88.0% survival at 2 years in the TEVAR group, versus 95.6% in the OMT group. Five-year follow-up (the INSTEAD-XL trial) was conducted via a special (controversial) statistical analysis method (Landmark analysis).18 Analysis showed that all-cause mortality in the TEVAR + OMT group versus OMT-alone group was 11.1% versus 19.3% (P = 0.13), aortic deaths were 6.9% versus 19.3% (P = 0.04), and progression of the pathology occurred in 27% versus 46.1% (P = 0.04), respectively.
5. The INSTEAD-XL trial was designed to evaluate patients with more chronic dissections (56 days in the stent-graft group vs 75 days in the medical management group). The controversy arose in that the Landmark method does not include periprocedural early mortality in the analysis. Detractors point out that the choice of Landmark analysis may have produced better apparent outcomes than would have been seen with standard analytic methods.
C. Other Pathologies TEVAR can also be utilized in patients with blunt thoracic aortic injuries due to high-speed deceleration, with significantly lower perioperative morbidity and mortality compared with open repair.19 Other lesions in the spectrum of aortic dissection (e.g., intramural hematoma/penetrating aortic ulcer) can also be managed with an endovascular technique, so as to exclude the aortic lesion, or to cover the intimal tear in any coexistent dissection. Endovascular techniques can also be utilized in cases of aortoesophageal fistula as a temporizing measure to prevent exsanguination and allow for fluid resuscitation.20
IV. Endograft Structure
Endovascular grafts are usually inserted via a transfemoral approach. Upon deployment, the endograft self-expands to exclude the native diseased aorta from the circulation and comes in contact with the aortic wall proximally and distally in a tight-seal fashion (Fig. 6.2). Significant variations in graft design exist. However, all stents are composed of a delivery system, main device, and device extensions.21
A. Delivery System The size of the delivery sheath depends on the diameter of the endograft that needs to be deployed to provide appropriate fixation. Delivery is usually accomplished via a femoral approach by direct surgical cutdown. If the diameter of the femoral or iliac artery is too small to withstand the delivery system, access can be obtained by direct puncture of the iliac artery or the aorta via a retroperitoneal incision, or by suturing a synthetic conduit onto the iliac artery.
FIGURE 6.2: The Zenith Alpha thoracic stent graft. Thoracic endovascular grafts require proximal and distal seal zones of least 2 cm. Permission for use granted by Cook Medical, Bloomington, Indiana.
B. Main Device The endograft can be straight or tapered and may or may not have a longitudinal support. The graft self-expands, but subsequent ballooning is an option. Fixation systems may include barbs or uncovered proximal stents.
C. Extensions These are utilized during deployment if adequate positioning of the endograft is not obtained, or if postdeployment aortography reveals endoleaks. Proximal or distal extension devices can provide a complete seal.
V. Available Endografts for TEVAR
Multiple devices are currently FDA approved for thoracic endovascular repair from different manufacturers (Table 6.1). These devices include the Gore TAG and CTAG (W.L. Gore & Associates, Newark, DE), Zenith TX2 and Zenith Alpha (Cook Medical, Bloomington, IN), Valiant (Medtronic Vascular, Santa Rosa, CA), and the Relay (Bolton Medical, Sunrise, FL).
A. TAG and CTAG
1. The TAG device (W.L. Gore & Associates) is a flexible tube-shaped stent-graft, lined with polytetrafluorethylene (ePTFE) “Teflon” and covered with an additional layer of Teflon and fluorinated ethylene propylene (FEP), to further reduce friction and the occurrence of endoleaks (Fig. 6.3). It is supported through its entire length with a nitinol exoskeleton. The proximal end of the graft consists of exposed stent apices, whereas the distal end remains in line with the graft material. Radiopaque bands are present at each end to facilitate placement under fluoroscopy. These flared endings are intended to improve sealing and attachment of the graft to the aortic wall.22
TABLE 6.1. Summary of Thoracic Device Characteristics
Device
TAG
CTAG
Zenith TX2
Zenith Alpha
Valiant
Relay
Manufacturer
W.L. Gore & Associates
W.L. Gore & Associates
Cook Medical
Cook Medical
Medtronic Vascular
Bolton Medical
Device structure
Tube-shaped stent-graft lined with ePTFE/FEP, and supported by a nitinol exoskeleton
Similar design to the TAG, but more conformable
Dacron graft sewn to a stainless steel stent
Similar to TX2
Self-expanding tube with nitinol scaffolding sewn to the outside of the graft material. Lacks a longitudinal support bar, for more flexibility
Self-expanding nitinol stent, sutured to a polyester fabric graft. Longitudinal support achieved via a nitinol wire
Proximal and distal ends
Flared exposed stent apices
Similar to the TAG device
External barbs proximally and distally. Extension BMS is available
Similar to TX2
Proximal end is bare stent with eight shorter bare stents. Distal stent graft with a closed web configuration
Two versions, the Relay with proximal bare stent, and the Relay-NBS, without bare stent. One distal configuration is available
Diameter (mm)
26-45
21-45
28-42
18-34
24-46
22-46
Length (cm)
10-20
10-20
12-21.6
10.5-16
Up to 22.7
10-25
Delivery system
20-24 F sheath
Sheathless delivery system
20-22 F delivery sheath
16-20 F sheath
Xcelerant delivery system
20-26 F delivery sheath
BMS, bare metal stent; ePTFE, polytetrafluorethylene; FEP, fluorinated ethylene propylene.
FIGURE 6.3: Original (top) and redesigned (bottom) GORE TAG devices. Reprinted with permission from Makaroun MS, Dillavou ED, Kee ST, et al. Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis. J Vasc Surg. 2005;41:1-9.
2. A next-generation device, the Conformable TAG (CTAG) shares a similar design but offers more conformability to accommodate more acute angles, often found in the aortic arch. This is achieved through modification of the material and the attachment of the exoskeleton to the graft.
3. TAG device is available in diameters from 26 to 45 mm in 10, 15, and 20 cm lengths. The delivery sheath ranges from 20 to 24 French in diameter depending on the
device size. CTAG offers a wider range of diameters (21-45 mm),23 with a sheathless delivery system. The endoprosthesis is constrained inside a deployment sleeve and mounted onto the leading end of the delivery catheter. Pulling the deployment knob, which is attached to the deployment line system, unlaces the sleeve and allows the self-expanding endoprosthesis to deploy. This allows the CTAG to conform to smaller and more tapered aortas and to provide a solution for nonaneurysmal aortic pathologies such as blunt aortic injury.22
4. The safety and efficacy of the TAG endograft have been demonstrated. Although the initial results with the TAG device were disappointing, and the trial was stopped owing to complications,24 further modifications of the device have proven to be efficacious. In a multicenter study comparing endovascular DTA repair using the TAG device with open repair, aorta-specific survival was significantly better in the endovascular group at 5 years (96% vs 88%, P = 0.24), and major adverse events were reduced at 30 days (21% vs 71%, P < 0.001) and at 1 year (42% vs 77%. P < 0.001).4,25
5. The Aortic Dissection Stent-graft OR Best Medical Treatment (ADSORB) trial, comparing outcomes of OMT only versus OMT and the Gore TAG device, in patients with uncomplicated type B dissection, demonstrated the safety of the device.26 The false lumen (FL) decreased in size in the OMT + TAG group (P < 0.001), whereas in the OMT group it increased. The true lumen (TL) increased in the OMT + TAG (P < 0.001), whereas in the OMT group it remained unchanged. The overall transverse diameter was the same at the beginning and after 1 year in the OMT group (42.1 mm), but in the OMT + TAG group it decreased (38.8 mm; P = 0.062). Remodeling with thrombosis of the FL, and reduction of its diameter is induced by the stent graft; however long-term results are still needed.
6. Criticism to the ADSORB study concerned the definition of FL thrombosis, which was not the same in the OMT plus TEVAR and OMT only groups. For patients treated with OMT plus TEVAR, the FL was considered thrombosed as long as no flow was visualized in the false lumen parallel to the endograft, excluding the distal 2 cm, whereas in the OMT group, the false lumen was only considered thrombosed if there was no flow in any segment of the thoracic aorta, a difference that would appear substantially to favor the TEVAR group.27
7. The safety and efficacy of the CTAG device was evaluated in a nonrandomized study with 51 patients suffering from blunt aortic injury,28 with no operative mortality and no major device events. Thirty-day mortality, unrelated to device, was 7.8%.
B. Zenith TX2 and Zenith Alpha
1. Zenith TX2 endograft (Cook Medical) and Zenith Alpha (new generation, low profile stents29) are two-piece systems, proximal and distal. They are constructed of full-thickness woven polyester fabric (i.e., Dacron), sewn to self-expanding special stainless steel stents, with braided polyester and monofilament polypropylene suture.
The graft body stents and the distal sealing stent are made from superelastic electropolished nitinol wire30 (Fig. 6.2). Active fixation at the proximal and distal ends is achieved via external barbs for each component. An extension bare metal stent is available, which can be used to distally fixate the graft over the origins of the visceral arteries. A modification of the TX2 device (Pro-form) is intended to improve conformability and apposition of the graft in the aortic arch during proximal descending thoracic aortic deployments, in order to minimize the risk of graft folding and collapse.31
2. Proximal and distal Zenith TX2 device components are available in diameters ranging from 28 to 42 mm, and the components range in length from 12 to 21.6 cm. Delivery sheath is a 20 or 22 French.29 Zenith Alpha is available in diameters from 18 to 34 mm, with component lengths from 10.5 to 16 cm.29 The devices are delivered through a 16-20 French sheath depending on the diameter of the device. Both devices are self-expanding; however, subsequent ballooning is an option when needed.
3. The safety and efficacy of the Zenith TX2 endograft were evaluated in a multicenter study of 230 patients with DTAs, who were treated with TEVAR (n = 160) or open repair (n = 70).30 Perioperative morbidity was significantly lower for endovascular repair (composite index 1.3 vs 2.9, P < 0.01). Endovascular repair was also associated with fewer cardiovascular and pulmonary adverse events; however, incidence of neurologic events was not significantly different. At 12 months, aneurysm growth was identified in 7.1%, endoleak in 3.9%, and migration (>10 mm) in 2.8% of the endovascular patients.
4. The Zenith TX2 dissection system shares a similar design, and its efficacy was evaluated in the STABLE trial, in 40 patients with complicated DescAD, defined by branch vessel malperfusion, impending rupture, aortic diameter ≥40 mm, rapid aortic expansion, and persistent pain or hypertension despite maximum medical therapy.32 Seven combinations of stent grafts and dissection stents were used, and all devices were successfully deployed and patent. One-year survival rate was 90%. Morbidity occurring within 30 days included stroke (7.5%), transient ischemic attack (2.5%), paraplegia (2.5%), retrograde dissection (5%), and renal failure (12.5%). Favorable aortic remodeling was observed during the course of follow-up, indicated by an increase in the TL size, and a concomitant decrease in the FL size along the dissected aorta, with completely thrombosed thoracic FL observed in 31% of patients at 12 months.
C. Valiant Thoracic Stent-Graft System
1. The Valiant endograft (Medtronic Vascular) is a modified version of the earlier Talent endograft system (withdrawn by manufacturer). It is composed of a self-expanding tube. The nitinol scaffolding of the stent graft is composed of a series of serpentine five-peaked springs stacked in a tubular configuration. The scaffolding in this device
is sewn to the outside of the graft material (not the inside, as with the Talent device) (Fig. 6.4). Valiant device lacks the longitudinal support bar of the earlier device, which gives more flexibility. The device has a modified proximal bare stent with eight shorter bare stents proximally. A distal stent graft component has a closed web configuration at the proximal end (no bare spring) and a closed web or an eight-peak bare-spring configuration at the distal stent end.33
FIGURE 6.4: The Valiant thoracic stant graft. Reprinted with permission from Fairman RM, Tuchek JM, Lee WA, et al. Pivotal results for the medtronic valiant thoracic stent graft system in the VALOR II trial. J Vasc Surg. 2012;56:1222-1231. e1221.
2. The graft is available in straight or tapered versions, with diameters ranging from 24 to 46 mm, and lengths up to 22.7 cm. It is compressed and preloaded into the Xcelerant delivery system (Medtronic Vascular), which consists of a single-use disposable catheter with an integrated handle.33
3. Valiant endograft efficacy was evaluated in a retrospective study with 180 patients,34 treating various descending aortic pathologies (66 patients with thoracic aneurysms, 22 with thoracoabdominal aneurysms, 19 with an acute aortic syndrome, 52 with aneurysmal degeneration of a chronic dissection, and 21 patients with traumatic aortic transection). Overall 30-day mortality for the series was 7.2%, with a stroke rate of 3.8% and a paraplegia rate of 3.3%. Mortality rates differed according to the indication, with the highest rate for thoracoabdominal aneurysms (27.3%) and lowest for acute traumatic rupture (0%).
4. The VALOR II trial (Evaluation of the Clinical Performance of the Valiant Thoracic Stent Graft System in the Treatment of Descending Thoracic Aneurysms of
Degenerative Etiology in Subjects Who Are Candidates for Endovascular Repair) has led to the approval of the Captivia Delivery System (Medtronic vascular) in the United States.33,35 A cohort of 160 patients with degenerative DTAs and thoracoabdominal aneurysms were followed up for 5 years. Technical success rate was 96.3%, and the 30-day mortality was 3.1%. 38.1% of patients had ≥1 major adverse event at 30 days, while 48.7% of patients had ≥1 major adverse event at 12 months.
FIGURE 6.5: In the Relay stent-graft, the curved nitinol wire starts below the second row of proximal covered stents and ends close to the distal stent, allowing for sufficient column strength while at the same time providing flexibility and torque response. A, Relay has an alignment zone (dotted arrow) to provide optimal alignment with aortic anatomy and allow proximal capture of the stent-graft for accurate placement. B, In Relay-NBS, the proximal end is covered with polyester vascular graft fabric (solid arrow) to optimize apposition of the proximal end of the graft to the lumen wall while minimizing trauma to the intima and risk of fabric infolding. Reprinted with permission from Zipfel B, Czerny M, Funovics M, et al. Endovascular treatment of patients with types A and B thoracic aortic dissection using Relay thoracic stent-grafts: results from the RESTORE Patient Registry. J Endovasc Ther. 2011;18:131-143.
5. Five-year survival was 64%, with 5% aneurysm-related mortality. Secondary intervention occurred in 6.8% of patients.
D. Relay
1. The Relay thoracic stent-graft system (Bolton Medical) is composed of a self-expanding nitinol stent, sutured to a polyester fabric graft, with a curved longitudinal nitinol wire for the purpose of providing longitudinal strength (Fig. 6.5). Two different proximal standard configurations are available, the RELAY, with the proximal bare stent, and a non-bare-stent model (RELAY-NBS). Only one distal configuration is present.36
2. It is available in straight and tapered configurations, with diameters ranging from 22 to 46 mm, and lengths from 10 to 25 cm. The delivery sheath ranges from 20 to 26 French, depending on the diameter of the device.
3. The European experience with Relay was demonstrated in the RESTORE registry, with a success rate of 97.3%.37 A cohort of 150 patients were prospectively
accrued, in whom thoracic aortic aneurysms was treated in 64.7%, and DescAD in 19.3%. Paraplegia rate was 3.3%, recovered paraparesis 3.3%, and stroke only 0.6%. Reinterventions were necessary in 8.7% of the cases. The 30-day mortality rate was 10%. Reintervention rate during 2-year follow-up was 8.9%, owing to two stent graft migrations, three proximal type I endoleak, four type III endoleak, and five distal type I endoleaks. No open conversion was needed during follow-up.
4. The use of Relay system in DescAD was evaluated in another study of the RESTORE registry,38 in which the majority of patients had type B AD (84%). The technical success rate was 95%. Thirty-day mortality was 8%, and the type I endoleak rate was 7%. The 2-year survival rate was 82% in the overall population, and 84% in patients with type B AD.
5. Bolton Medical’s next generation device, the (Relay Pro), is currently being developed, offering diameters as small as 19 French, in both stented and NBS configurations.
The pivotal trials providing evidence regarding the thoracic devices have been summarized (Tables 6.2 and 6.3).
VI. Investigational Devices
These devices are currently being investigated but have not yet been approved in the United States. These include the LeMaitre TAArget device, the JOTEC E-Vita stent-graft system, and the Streamliner Multilayer Flow Modulator.
A. TAArget
1. The TAArget thoracic stent-graft (previously labeled EndoFit, LeMaitre Vascular) is composed of a nitinol skeleton of Z-shaped stents that are encapsulated between two thin sheets of expanded ePTFE. The Z-shaped stents aim at providing longitudinal support without a support bar. The device can be straight or tapered, and the proximal end is available with and without external fixation with a bare metal stent, allowing for different configurations of the device.39
2. The graft is available in diameters from 30 to 42 mm, with lengths from 7 to 22 cm. The graft is deployed through a 22 or 24 French sheath depending on the diameter of the device.40
3. In a study with 41 patients with various descending aortic pathologies, who were managed using the TAArget device, the graft was successfully deployed in all 41 patients. In-hospital mortality was 7.3%, and three patients developed endoleaks, with only one patient requiring intervention. One patient suffered from spinal cord ischemia. Two-year mortality was 17%, with 11% aneurysm-related mortality.39
4. Another study with 46 aneurysm patients and 41 with DescAD, managed using the TAArget device,40 showed 100% deployment success rate. In-hospital mortality was 9.2%, and neurological complications occurred in 9.3% of patients, including five strokes (two fatal) and three cases of paraplegia. Five patients had immediate
proximal type I endoleak. Mortality rate over a follow-up period of 5.2 months was 11.4% but was not felt to be aneurysm or stent-graft related.
TABLE 6.2. Summary of Evidence About Various Thoracic Devices in Aortic Dissection
Study
Year
Device
Aim
Number of Patients
Type of Dissection
Success
Results
Mortality
Complications
Comments
INSTEAD trial17
2009
Talent graft
Compare TEVAR + OMT to OMT alone in uncomplicated type B AD
140
Uncomplicated chronic type B AD
Access obtained in 70/72 cases randomized to TEVAR + OMT (97.2%)
Aortic remodeling occurred in 91.3% with TEVAR vs 19.4% in OMT group (P < 0.01)
No difference in 2-y all-cause mortality
Paraplegia: 3 cases in TEVAR vs 1 in OMT group
INSTEAD-XL trial18
2013
Talent graft
Long-term follow-up of the INSTEAD trial
140
Uncomplicated chronic type B AD
Access obtained in 97.2% of cases
Landmark analysis suggested a benefit of TEVAR for all end points (mortality and progression) between 2 and 5 y
All-cause mortality was lower in TEVAR group: 11.1% vs 19.3% (P = 0.13)
Aorta-specific mortality was lower in TEVAR group (6.9% vs 19.3%; P = 0.04) at 5 y
Landmark method does not include periprocedural early mortality in the analysis
ADSORB trial26
2014
Gore TAG
Compare OMT + TAG device to OMT alone in uncomplicated type B AD
61
Uncomplicated acute type B
Access obtained in 100% of cases
Incomplete FL thrombosis: 43% in TAG group vs 97% in OMT group
FL decreased and TL increased in TAG group and increased in the OMT group (P < 00.1)
No mortality within 30 d
One death in the TAG + OMT group during follow-up due to cardiac arrest, but no autopsy was performed
STABLE trial32
2012
Proximal Zenith TX2 and distal BMS
Evaluate the composite TX2 device in complicated type B AD
40
Complicated acute type B AD
Technical success: 100%
Complete FL thrombosis: 31% at 1 y
1-y survival: 90%
30-d morbidities:
Stroke: 7.5%
TIA: 2.5%
Paraplegia: 2.5%
Renal failure: 12.5%
Complications defined by branch vessel malperfusion, impending rupture, aortic diameter ≥40 mm, rapid aortic expansion, and persistent pain or hypertension despite maximum medical therapy
RESTORE trial37
2008
Relay
Evaluate the efficacy of the Relay graft in DTA and DescAD
150
Acute uncomplicated type B AD
Technical success: 97.3%
Aneurysm was the most common pathology treated (64.7%) followed by dissections (19.3%)
30-d mortality was 10%
Paraplegia: 3.3%
Recovered paraparesis: 3.3%
Stroke: 0.6%
Reintervention at 2 y: 8.9%
Zipfel et al38
2011
Relay
To evaluate the safety and performance of Relay stent-grafts in patients with acute or chronic aortic dissections
91
Acute and chronic uncomplicated type A and type B AD
Technical success: 95% (97% in acute, 95% in chronic, and 93% in type B dissections)
Relay stent graft showed favorable outcomes in treatment of thoracic aortic dissections
30-d mortality was 8% (13% in acute and 5% in chronic dissections); all deaths occurred in patients with type B dissections
2-y survival:
Overall: 82%
Type B AD: 84%
Paraplegia, paraparesis, and stroke occurred in 4, 1, and 2 patients, respectively; 2 cases of paraplegia occurred in patients with acute type B dissections
Type I endoleak: 7% (7% in acute and 8% in chronic dissections); all occurred in patients with type B dissections
AD, aortic dissection; ADSORB, acute dissection stent graft or best medical treatment; BMS, bare metal stent; DTA, descending thoracic aneurysm; FL, false lumen; INSTEAD, investigation of stent graft in aortic dissection; OMT, optimized medical treatment; RESTORE, European experience in the RELAY endovascular registry for thoracic disease STABLE, study of thoracic aortic type B dissection using endoluminal repair; TEVAR, thoracic endovascular aortic repair; TL, true lumen.
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