• Contact
    Contact us
    USA OFFICE
    Office timings 9 am to 1 pm (EST)
    195 State Avenue
    Suite # 201
    New York CT 06032
    Tel: +1 (860) 674 8865
    Fax: +1 (860) 674 9007

24/7 HELPLINE 800-5234-987

Aneurysm Repair

INTRODUCTION: Endovascular aneurysm repair (EVAR) is an important advance in the treatment of abdominal aortic aneurysm (AAA). EVAR is performed by inserting graft components folded and compressed within a delivery sheath through the lumen of an access vessel, usually the common femoral artery. Upon deployment, the endograft expands, contacting the aortic wall proximally and iliac vessels distally to exclude the aortic aneurysm sac from aortic blood flow and pressure (figure 1).

Compared with open AAA repair, EVAR is associated with a significant reduction in perioperative mortality, primarily because EVAR does not require operative exposure of the aorta or aortic clamping. Since the approval of endograft devices for use in the United States, there has been a 600 percent increase in the annual number of EVAR procedures performed, with EVAR accounting for nearly half of AAA repairs. Concurrent with the increased use of EVAR, a decrease in the incidence of ruptured AAA and associated morbidity and mortality has been reported in the United States, likely due to the ability to offer EVAR to patients who would not otherwise be candidates for open surgical repair [1,2].

Endovascular repair of abdominal aortic aneurysm is reviewed here. General issues regarding the management of abdominal aortic aneurysm, and the clinical features and diagnosis of this condition, are presented separately. (See “Management of asymptomatic abdominal aortic aneurysm”.)

ANATOMIC CONSIDERATIONS: The abdominal aorta is the most common site of arterial aneurysm. The abdominal aorta is defined as aneurysmal when a localized dilation is identified, and the diameter of the dilated region is increased more than 50 percent relative to normal aortic diameter [3]. The normal diameter of the aorta at the level of the renal arteries is approximately 2.0 cm (range 1.4 to 3.0 cm). An aortic diameter greater than 3.0 cm is considered aneurysmal for most individuals.

Aortoiliac anatomy: The abdominal aorta is a retroperitoneal structure that begins at the hiatus of the diaphragm and extends to its bifurcation into the common iliac arteries at the level of the fourth lumbar vertebra (figure 2). It lies slightly left of the midline to accommodate the inferior vena cava which is in close apposition. The branches of the aorta (superior to inferior) include the left and right inferior phrenic arteries, left and right middle suprarenal arteries, the celiac axis, superior mesenteric artery, left and right renal arteries, possible accessory renal arteries, left and right gonadal arteries, inferior mesenteric artery, left and right common iliac artery, middle sacral artery and the paired lumbar arteries (L1-L4).

The common iliac artery bifurcates into the external iliac and internal iliac arteries at the pelvic inlet (figure 3). The internal iliac artery, also termed the hypogastric artery, gives off anterior and posterior branches to the pelvic viscera and also supplies the musculature of the pelvis. The external iliac artery passes beneath the inguinal ligament to become the common femoral artery [4].

Aneurysm extent: Abdominal aortic aneurysms (AAAs) are described as infrarenal, juxtarenal (pararenal), or suprarenal depending upon the involvement of the renal or visceral vessels.
– Infrarenal: aneurysm originates below the renal arteries
– Juxtarenal: aneurysm originates at the level of the renal arteries
– Suprarenal: aneurysm originates above the renal arteries

Abdominal aortic aneurysms (AAAs) most often occur in the segment of aorta between the renal and inferior mesenteric arteries; approximately 5 percent involve the renal or visceral arteries (figure 4).

Up to 40 percent of AAAs are associated with iliac artery aneurysm(s). The normal size and diameter corresponding to aneurysm for the iliac artery is discussed elsewhere. (See “Iliac artery aneurysm”, section on ‘Definition of iliac aneurysm’.)

Although the majority of endovascular aneurysm repairs are performed on aneurysms affecting the infrarenal aorta and iliac arteries, endovascular repair of juxtarenal and suprarenal aneurysms has been performed using advanced endovascular techniques with specialized investigational endografts. (See ‘Advanced devices and techniques’ below.)

Measurement definitions: Several aortic measurements are important for determining the feasibility of endovascular aneurysm repair and for endograft sizing. The definitions of important terms are as follows [5]:
– Aortic neck diameter: The aortic diameter at the lowest renal artery.
– Aortic neck length: The distance from the lowest renal artery to the origin of the aneurysm.
– Aortic neck angulation: The angle formed between points connecting the lowest renal artery, the origin of the aneurysm, and the aortic bifurcation.
– Conical/reverse tapered aortic neck: A conical neck is present when the diameter of the aorta 15 mm below the lowest renal artery is ≥10 percent larger than the diameter of the aorta at the lowest renal artery.
– Infrarenal aortic length: The distance from the lowest renal artery to the aortic bifurcation.

Other measurements that are important for sizing endografts include the maximal common iliac artery diameter, minimum external iliac artery diameter, distance from the aortic neck to the iliac bifurcation, and maximal AAA sac diameter. The criteria defining anatomic suitability for endovascular aneurysm repair are discussed below. (See ‘Anatomic suitability’ below.)

Renal artery anomalies: Accessory renal arteries are present in up to 30 percent of the population, and commonly originate from the lumbar aorta [6]. Exclusion of an accessory renal vessel by an endograft can lead to partial renal infarction.

Horseshoe kidney, a renal fusion abnormality, is associated with anomalous arterial supply with multiple renal arteries that may be derived from the aorta, or the iliac (common, external, or internal) or middle sacral arteries. Renal arteries often arise from the aneurysmal aortic segment. (See “Renal ectopic and fusion anomalies”.)

AORTOILIAC IMAGING: Prior to consideration for endovascular aneurysm repair, aortoiliac imaging is needed to define the anatomy, determine the feasibility of endovascular repair, and choose the size and configuration of endograft components. Computed tomography (CT) is typically used for elective abdominal aortic aneurysm (AAA) repair, but under urgent or emergent circumstances, endograft feasibility and sizing can be determined intraoperatively using arteriography. (See “Surgical and endovascular repair of ruptured abdominal aortic aneurysm”, section on ‘Endovascular repair’.)

We obtain CT angiography of the abdomen and pelvis with ≤2.5 mm cuts with three-dimensional (3-D) reconstruction. Although two-dimensional (2-D) CT images can be used, measurement errors (aortic diameter, aortic length) can occur due to volume averaging. In addition, aortic diameter measurements will be overestimated if the aorta is angulated and the longitudinal axis is not perpendicular to the imaging plane. CT angiography with 3-D reconstruction allows measurements to be made that are perpendicular to the true axis of the aorta (image 1). Centerline length measurements can also be obtained with 3-D reconstruction (image 2). 3-D length measurements are more accurate than 2-D measurements and can improve graft sizing, particularly in patients with tortuous vessels [7].

Magnetic resonance (MR) angiography can be used for preoperative endograft planning preoperatively; however, gadolinium administration in the setting of renal dysfunction is a relative contraindication.

The use of digital subtraction arteriography (DSA) to obtain aortic measurements is limited by measurement errors due to parallax and magnification. Since the inner lumen is imaged, but not the wall of the aorta, DSA cannot evaluate the true lumen diameter, extent of thrombus, plaque, or degree of calcification. Errors in length measurement can occur when intraluminal catheters that follow the shortest distance around the curves of the aorta are used. Arteriography can be used in emergent situations to estimate the proximal aortic diameter and the diameter of the iliac graft landings zones when treating a ruptured AAA with EVAR, but it is otherwise not recommended as a routine pre-EVAR imaging modality. (See “Surgical and endovascular repair of ruptured abdominal aortic aneurysm”, section on ‘Endovascular repair’.)

Surface duplex ultrasound is not an adequate imaging modality for determining feasibility or planning EVAR. On the other hand, intravascular ultrasound (IVUS), which provides accurate intraoperative diameter and length measurements (based on branch vessel location), can be used as the sole imaging modality during EVAR and is a particularly attractive imaging alternative for patients with renal insufficiency. IVUS is best used during EVAR and not as a preoperative imaging modality given its invasive nature, but has limited availability and requires significant skill and experience to perform and interpret.

INDICATIONS FOR REPAIR: Repair of AAA is indicated for patients with abdominal aortic aneurysm (AAA) who are symptomatic (tenderness or abdominal or back pain, evidence for embolization, rupture), have an AAA ≥5.5 cm, or an AAA that has expanded by more than 0.5 cm within a six-month interval. The clinical evaluation and management of AAA are discussed in detail elsewhere. (See “Clinical features and diagnosis of abdominal aortic aneurysm” and “Management of asymptomatic abdominal aortic aneurysm”.)

Anatomic suitability: Anatomic suitability is the most important determinant for successful endovascular aneurysm repair (EVAR) in the long term. With early endograft designs, about 50 percent of patients were not candidates for EVAR because of the site, extent, or morphology of the aneurysm, or unsuitability of access vessels. The availability of devices that allow for shorter proximal seal zones and lower profile devices has expanded the use of EVAR to almost two-thirds of patients with an infrarenal AAA.

To exclude blood flow from the aneurysm sac, the endograft must provide an adequate seal where the endograft contacts the arterial wall proximally at the aortic neck and distally in each of the iliac arteries, otherwise known as the landing zones. The security of the repair relies solely upon the radial force generated by the graft at the landing zones since endografts do not have any suture-mediated stability. Thus, certain anatomic criteria must be fulfilled to perform EVAR (figure 5) [8]. These criteria are measurements of the aortic neck, iliac, and femoral arteries (figure 5). Definitions for the measurement terms are described above and the criteria for each are described in detail below. (See ‘Measurement definitions’ above.)

Characteristics of currently available endografts and potential advantages for different anatomic situations are given in the table (table 1). The specific criteria recommended for a specific device are given in the instructions for use (IFU) that are published and packaged with each device used. Failure to follow device specifications increases the risk for complications. (See ‘Perioperative morbidity and mortality’ below.)

Aortic neck diameter: The required endograft diameter is determined by measuring the aortic neck diameter (eg, 20 mm) and adding an additional 15 to 20 percent of the aortic neck diameter (20 mm + 3 to 4 mm = 23 to 24 mm). Under-sizing the diameter of the endograft will lead to an inadequate seal and failure to exclude the aneurysm. Over-sizing the endograft 15 to 20 percent over the measured aortic neck diameter should provide sufficient radial force to prevent device migration. Commercially-available devices have endograft diameters as large as 36 mm, which allow endovascular repair of aneurysms to a maximal aortic neck diameter of 32 mm. However, the durability of EVAR fixation in an aneurysmal aortic neck (ie, ≥30 mm) remains to be determined. Over-sizing the endograft may lead to kinking of the device, which can form a nidus for thrombus formation or endoleak. Over-sizing may result in incomplete expansion of the endograft with infolding and inadequate seal, and can also be associated with intermediate and long-term neck expansion [9].

Aortic neck length: The aortic neck length should be at least 10 to 15 mm to provide an adequate proximal landing zone for endograft fixation.

Qualitative assessment of the proximal neck is also important. Ideally, the proximal aorta should be normal in appearance, without significant thrombus or calcification. Although not an absolute contraindication for EVAR, large amounts of thrombus or calcification will interfere with fixation of the graft and increase the risk for graft migration or type I endoleak. (See ‘Handling endoleak’ below.)

Aortic neck angulation: Ideally, the aortic neck angle should be less than 60º. Angles that are greater lead to difficulties in implantation, kinking, endoleak, and the potential for distal device migration. Severe angulation (>60°) is generally considered to be a contraindication to EVAR. However, the ability to place a device in aneurysms with significant angulation at the neck is ultimately determined by the conformability of the specific device type and its delivery characteristics (table 1). The specific characteristics of individual devices are discussed in detail elsewhere. (See “Endovascular devices for abdominal aortic repair”.)

Iliac artery and access vessel morphology: Suitable iliac artery morphology is also required for endograft placement. The iliac arteries should have a minimal amount of calcification and tortuosity, and no significant stenosis or mural thrombus should be present in the distal graft landing zones. The common iliac artery is the preferred distal attachment site, but the external iliac artery can also be used. When the external iliac artery is used for distal fixation (eg, common iliac artery aneurysm), the origin of the hypogastric artery (ie, internal iliac artery) is covered by the endograft. Thus, prior to endograft placement, the hypogastric artery will need to be embolized to prevent backbleeding into the aneurysm sac, unless there is severe stenosis at its origin. (See “Surgical and endovascular repair of iliac artery aneurysm”, section on ‘Associated abdominal aortic aneurysm’.)

A minimal external iliac artery diameter of 7 mm is needed to allow safe passage of the endograft delivery sheath. The common iliac artery diameter should measure between 8 and 22 mm, and the length of normal diameter common iliac artery into which the limbs of the endograft will be fixed should measure at least 15 to 20 mm to achieve an adequate seal.

Focal narrowing and mild angulation can be overcome with standard guidewire and catheter techniques, while diffuse narrowing or significant calcification is more problematic. If the device fails to pass, an iliac conduit can be created [10]. (See ‘Iliac conduits’ below.)

Aneurysmal iliac arteries (>22 mm) are treated by excluding them. The management of iliac artery aneurysm in conjunction with abdominal aortic aneurysm is discussed elsewhere. (See “Surgical and endovascular repair of iliac artery aneurysm”, section on ‘Associated abdominal aortic aneurysm’.)

Other considerations: The inferior mesenteric artery is often occluded by thrombus in patients with an abdominal aortic aneurysm, and in these cases, excluding the inferior mesenteric artery with an endograft will be of no consequence. However, if the inferior mesenteric artery is patent but associated with significant stenosis of the superior mesenteric artery, the inferior mesenteric artery may provide important collateral blood flow to the intestine. Under this circumstance, covering the origin of a patent inferior mesenteric artery with an endograft may lead to intestinal ischemia [10].

A visceral hybrid procedure combines endovascular exclusion of the aneurysm with open visceral revascularization, and is more commonly used for the endovascular repair of thoracoabdominal aortic aneurysm (TAA), but in some circumstances may be needed in patients with AAA who have visceral artery disease. Prior to endovascular repair, retrograde revascularization of the visceral and renal arteries is performed (surgical debranching) using an open approach, allowing subsequent coverage of the origins of these vessels during endovascular stent-graft placement [11-13].

Contraindications: Endovascular repair of AAA is contraindicated in patients who do not meet the anatomic criteria required to place any of the available endografts (table 1). Adverse anatomic features include suprarenal or juxtarenal AAA, small caliber vessels, circumferential aortic calcification, and extensive tortuosity. Depending upon the location of the main and accessory renal arteries, endovascular repair may also be contraindicated for the management of AAA associated with horseshoe kidney. A variety of next-generation devices are being developed to treat suprarenal and juxtarenal abdominal aortic aneurysms. (See ‘Anatomic suitability’ above and ‘Endografts’ below and “Endovascular devices for abdominal aortic repair”.)

A relative contraindication to endovascular aneurysm repair (EVAR) is the inability to comply with the required post-EVAR surveillance. (See ‘Endograft surveillance’ below.)

Whether younger patients (<60 years of age) who are not at high risk for open surgery should undergo open surgical repair versus EVAR remains controversial. Surveillance over an extended period of time exposes the patient to greater levels of cumulative radiation, and EVAR does not completely eliminate the risk of future aortic rupture. Guidelines from major medical and surgical societies emphasize an individualized approach when choosing endovascular repair, taking into account the patient’s age and risk factors for perioperative morbidity and mortality [14-16]. The decision for open surgical repair versus endovascular repair is reviewed elsewhere. (See “Management of asymptomatic abdominal aortic aneurysm”, section on ‘Open versus endovascular aneurysm repair’ and ‘Preoperative risk assessment’ below.)

ENDOGRAFTS: Endovascular repair of abdominal aortic aneurysm is accomplished using a fabric-covered stent, termed an endograft or stent-graft. The first endovascular aneurysm repair (EVAR) was performed in 1987 by Nicholas Volodos in Kiev [17]. Juan Parodi popularized stent-grafting following his initial clinical experience in 1991, and was the driving force for commercializing stent-graft systems [18]. Stent-grafts were approved for clinical use in the United States in 1999.

Adoption of stent-graft technology by vascular surgeons has been rapid. EVAR has become a preferred approach across all ages for the repair of infrarenal abdominal aortic aneurysm (AAA) due to decreased perioperative morbidity and mortality [1,2,19].

Stent-graft design: Six stent-graft systems are currently available in the United States. These are listed below and discussed in detail elsewhere. (See “Endovascular devices for abdominal aortic repair”.)
– AneuRx (Medtronic, Inc., Minneapolis, MN)
– Talent (Medtronic, Inc., Minneapolis, MN)
– Endurant (Medtronic, Inc., Minneapolis, MN),
– Excluder (W.L. Gore and Associates, Flagstaff, AZ)
– Zenith (Cook, Inc., Bloomington, IN)
– Powerlink (Endologix, Irvine, CA)

New endograft designs are continually being tested to enhance performance. Targeted improvements have focused upon lower device and delivery profiles, more accurate deployment, improved fixation systems, and flexibility in managing challenging anatomy. These improvements, along with increased operator experience, have led to improvements in the short-term and long-term results of endovascular aneurysm repair, and have expanded the application of endovascular repair to many whose aortic anatomy was previously deemed unsuitable. Careful preoperative sizing and planning, along with strict adherence to device-specific instructions for use, lead to the best outcomes. Other devices that have received approval for use in other countries or are at the clinical trial or preapproval stage in the United States are discussed separately. (See “Endovascular devices for abdominal aortic repair”, section on ‘Withdrawn and investigational devices’.)

Endovascular grafts for infrarenal aneurysm repair share a bifurcated, modular design. Although there are variations from device to device, three components (delivery system, main body, and iliac extensions) are common to all endograft device systems and are briefly described below.
– Delivery system: The endograft is typically delivered through the femoral artery, either percutaneously or by direct surgical cutdown. If the femoral artery is too small to accommodate the delivery system, access can be obtained by suturing a synthetic graft to the iliac artery (ie, iliac conduit) through a retroperitoneal low abdominal incision. The size of the delivery system varies depending upon the device diameter.
– Main body device: The main body device is usually a bifurcated graft, but unibody grafts are available for use in special circumstances (image 3). Bifurcated-to-unilateral graft conversion kits are also available and effectively turn a bifurcated main body graft into a unibody graft by occluding one of the two proximal iliac limbs. The length of the limb(s) of the main body device varies. Two-component bifurcated grafts have one short and one long iliac limb. Three-component bifurcated devices have two short limbs. Endovascular grafts rely primarily upon tension to maintain the positioning of the main body device. Main body fixation is classified as infrarenal or suprarenal. Devices with infrarenal fixation may have barbs or hooks on the outer aspect of the devices, whereas suprarenal fixation is accomplished with a portion of uncovered graft extending superior to the renal arteries. Devices with suprarenal fixation may also have barbs and hooks.
– Iliac extensions: One or more iliac extension devices are required to complete the endograft construction. Following the deployment of the main body of a two-component system, the attached iliac limb is pulled down and deployed into the ipsilateral iliac artery. A separate iliac device is introduced into the contralateral iliac artery to complete the endograft. For a three-component device, both of the iliac limbs are introduced separately. Additional iliac extensions may be needed to obtain a proper seal in the iliac artery distally. (See ‘Endograft placement’ below.)

The degree of structural support (nitinol or stainless steel stents) throughout the graft varies from device to device. The support structure may be internal or external to the graft fabric, which is typically made of polyester (eg, Dacron) or polytetrafluoroethylene (PTFE). Proponents of designs that have less metallic support structure claim the device is better able to adapt to changes in aneurysm configuration over time. On the other hand, some physicians feel that fully supported endografts are less prone to kinking and subsequent thrombosis.

Advanced devices and techniques: When aneurysmal disease is more extensive, involving the visceral vessels proximally or associated with common or hypogastric artery aneurysms, the complexity of the required endovascular or open repair increases. Fenestrated and branched graft technology is under investigation to manage more challenging anatomy without the need for surgical debranching. The early results using these endografts have been promising, with high rates of successful exclusion of juxtarenal and thoracoabdominal aneurysms, but with an increased risk of visceral artery or stent-branch occlusion. The devices and techniques for more advanced endovascular repair are briefly reviewed below and are discussed in more detail elsewhere. (See “Endovascular devices for abdominal aortic repair”, section on ‘Advanced devices’ and “Complications of endovascular abdominal aortic repair”, section on ‘Ischemic complications’.)
– Fenestrated: Fenestrated endografts have openings in the fabric of the endograft, which allow flow into the visceral arteries. Stent-grafts with fenestrations at the renal arteries can be used when the proximal aortic neck is short (ie, <10 mm) [20,21].
– Branched: Branched grafts have a separate small graft sutured to the basic endovascular graft for deployment into a vessel to preserve flow into it. Branched grafts have been designed to accommodate the hypogastric (ie, internal iliac) and renal arteries.
– Chimney grafts: The chimney (ie, snorkel) endografting technique is used to preserve perfusion to branch vessels when an endograft needs to be placed in a suprarenal position to gain additional neck length [22]. Peripheral stents are placed into the branch vessel(s) before the aortic endograft is completely deployed. The branch vessel stent is deployed alongside the endograft (parallel position between the inside of the aortic wall and outside the endograft) [23,24]. Although this technique maintains flow into the visceral vessels, complications related to device insertion and type I endoleak continue to be a problem. In the absence of available fenestrated or branched grafts in the United States, chimney grafts remain a feasible endovascular option for high-risk patients who have more extensive abdominal aortic aneurysms, particularly in emergency situations.

Choice of graft: There are no clear advantages of one stent-graft design over another. The overall performance among the available devices is similar and the available data confirm uniformly low complication rates. (See “Endovascular devices for abdominal aortic repair”.)

The choice of a particular device design is based upon multiple factors, including patient anatomy, operator preference, and cost. An endograft system that can handle all types of AAA, including those with angulated or tortuous anatomy, has yet to be achieved.

Bifurcated grafts are most often chosen, but are not appropriate for patients with unilateral severe iliac stenosis or occlusion. Under this circumstance, unibody (nonbifurcated) grafts, also known as aorto-uni-iliac (AUA) devices, are used. AUI devices are used when contralateral iliac access or gate cannulation is difficult or impossible, and for the treatment of some ruptured aneurysms for expeditious control of hemorrhage. After deployment of an AUI device, a plug will need to be inserted into the contralateral iliac artery if it remains patent to prevent retrograde flow of blood into the aneurysm sac. To provide adequate perfusion to the contralateral lower extremity, a femoro-femoral crossover bypass may be needed.

Whether to use a graft with suprarenal or infrarenal fixation remains debated. Suprarenal fixation may provide more durable proximal fixation of the stent-graft when anatomic features are not optimal, such as with a short aortic neck, aortic angulation, conical aortic neck, or circumferential mural thrombus or calcification. However, the placement of stents in the region of the visceral vessels has raised concerns for embolization both at the time of the endograft placement and over time. Suprarenal fixation may lead to a higher incidence of small renal infarcts, but most are not clinically evident. However, in the face of preexisting renal insufficiency, suprarenal fixation should be used with caution.

Aortic endografts are prefabricated in various diameters and lengths. Once the graft design has been chosen, the particular device components that are used are determined by the measurements and configuration of the aneurysm being treated. The various manufacturers provide templates to assist the surgeon in choosing graft components based upon aneurysm measurements. (See ‘Measurement definitions’ above.)

Cost: There is some variability in the cost of EVAR, partially based upon the choice of the endograft and number of device components needed to complete the repair. The list price for main body devices ranges from about $8300 for the AneuRx graft to $11,200 for the Powerlink graft. Various other components, such as ipsilateral and contralateral limbs, limb extensions, and other devices needed to correct any endoleaks add cost per component used. Negotiated institutional prices for the grafts may vary from the list price, and costs related to the surgical suite, operating personnel, anesthesia services, and hospital costs based on the type of hospital bed and length of hospital stay are also variable. Other costs are incurred following discharge from the hospital for ongoing surveillance and re-intervention due to endoleak, when needed.

Compared with open repair of AAA, EVAR is more costly [25-31]. In an analysis of the EVAR 1 trial, the mean costs for the initial EVAR and open repair were £13,019 ($20,271 US) and £11,842 ($18,438 US), respectively [26,30]. The difference in lifetime cost was £3519 ($5479 US) higher with EVAR, but there was only a very small difference in quality-adjusted life-years (QALYs) of -0.032 (95% CI, -0.117 to 0.096) in favor of open repair. In EVAR 2, the mean cost difference was £10,596 ($16,499 US) higher for EVAR compared with open repair.

PREOPERATIVE RISK ASSESSMENT: Although endovascular aneurysm repair (EVAR) is associated with lower perioperative morbidity and mortality compared with open surgical repair, there is a small risk that the endovascular repair may need to be converted to an open repair, and thus, patients should be evaluated and prepared as if undergoing an open surgical repair. Coronary artery disease (CAD) is the leading cause of early and late mortality following AAA repair, and other comorbidities such as chronic obstructive pulmonary disease (COPD) and renal insufficiency also increase perioperative morbidity and mortality. We agree with the Society for Vascular Surgery and other societies that recommend a comprehensive assessment of medical comorbidities prior to endovascular aneurysm repair (EVAR) including cardiac, pulmonary, and renal evaluation, also taking into account hypertension and patient age as relevant risk factors for morbidity and mortality [32,33]. The evaluation of cardiopulmonary risk and risk management strategies are discussed in detail elsewhere. (See “Estimation of cardiac risk prior to noncardiac surgery” and “Management of cardiac risk for noncardiac surgery” and “Evaluation of preoperative pulmonary risk” and “Strategies to reduce postoperative pulmonary complications”.)

PREPARATION

Antithrombotic therapy: Patients undergoing AAA repair (endovascular or open surgery) are considered to be at moderate to high risk for deep venous thrombosis and thromboprophylaxis is indicated. Thromboprophylaxis is discussed in detail elsewhere. (See “Prevention of venous thromboembolic disease in surgical patients”, section on ‘Moderate risk general and abdominal-pelvic surgery patients’ and “Prevention of venous thromboembolic disease in surgical patients”, section on ‘High risk general and abdominal-pelvic surgery patients’.)

In a study of 193 patients undergoing AAA repair, the incidence of thromboembolism was lower for endovascular aneurysm repair compared with open surgery; however, the incidence of deep vein thrombosis following EVAR was 5.3 percent in spite of pharmacologic thromboprophylaxis [34]. Delayed initiation of pharmacologic prophylaxis was associated with a trend toward an increased incidence of deep venous thrombosis.

Antibiotic prophylaxis: Prior to endograft placement, antibiotic prophylaxis is recommended within 30 minutes of the skin incision (table 2). A first generation cephalosporin or, in the case of a history of penicillin allergy, vancomycin, is recommended. Antibiotics are discontinued within 24 hours given the lack of added benefit beyond that time frame. (See “Overview of control measures to prevent surgical site infection”.)

Prevention of contrast-induced nephropathy: EVAR increases the risk of renal complications, primarily due to the administration of intravenous contrast agents but potentially also related to the dislodgement of embolic debris by manipulation of catheters and wires near the renal arteries, or impingement of the real ostia by the graft or suprarenal fixation portion of the stent-graft. When EVAR will be performed in a patient with preexisting renal insufficiency, strategies to reduce the risk for contrast-induced nephropathy should be used [32]. These strategies are discussed in detail elsewhere. (See “Prevention of contrast-induced nephropathy”.)

Prophylactic renal artery stenting: The need to deploy a stent-graft near the origin of stenotic renal arteries is not uncommon. Although grafts with suprarenal fixation do not seem to affect renal function in patients with normal renal arteries, it is not clear if this holds true in the setting of severe renal artery stenosis and preexisting renal insufficiency. Whether prophylactic renal artery stenting should be performed in this setting is unclear. If a device with suprarenal fixation is needed, the possibility that the renal artery flow will be compromised due to the suprarenal struts needs to be weighed against the risks and potential benefits of prophylactic renal artery stenting. (See “Chronic kidney disease associated with atherosclerotic renovascular disease”.)

Hypogastric embolization: Hypogastric (ie, internal iliac artery) embolization may be needed to prevent type II endoleak during endovascular repair of aortic aneurysms involving the distal common iliac artery and/or hypogastric artery (ie, internal iliac artery). When unilateral hypogastric embolization is needed, it is often performed preoperatively; however, it can also be performed just prior to endovascular stent-graft placement. Patients with bilateral iliac artery aneurysms generally undergo a staged approach. Hypogastric embolization increases the proportion of patients who will have anatomy that is suitable for endovascular aneurysm repair. The endovascular management of patients with iliac artery aneurysm in conjunction with abdominal aortic aneurysm repair is discussed elsewhere. (See “Surgical and endovascular repair of iliac artery aneurysm”.)

ENDOGRAFT PLACEMENT: Endovascular aneurysm repair (EVAR) is performed by inserting folded graft components into the aorta to construct an endograft, which expands upon deployment, contacting the aortic wall proximally and the iliac vessels distally to exclude the aortic aneurysm sac from aortic blood flow and pressure.

The chosen device and its components should be present in the operating room before the start of the procedure and additional device components, guidewires, and sheaths should be immediately available to manage any technical issues that might arise.

Centers treating AAA using EVAR should ideally be equipped with a dedicated endovascular operating suite in which conversion to open repair can be performed efficiently, if needed. Endovascular aneurysm repair (EVAR) can be performed using portable digital subtraction fluoroscopic imaging or fixed imaging systems. Although fixed imaging systems provide better image quality and may include concomitant computed tomography (CT) and three-dimensional imaging, newer generation portable fluoroscopic systems provide adequate detail for routine EVAR.

Once the patient is anesthetized, endovascular aneurysm repair is accomplished through an orderly sequence that includes gaining vascular access, placement of arterial guidewires and sheaths, imaging to confirm aortoiliac anatomy, main body deployment, gate cannulation (bifurcated graft), iliac limb deployment, graft ballooning, and completion imaging. The general technique for routine endovascular repair is described below, and typical variations needed for troubleshooting common problems. The complications associated with EVAR are discussed separately. (See “Complications of endovascular abdominal aortic repair”.)

Anesthesia: Endovascular aneurysm repair (EVAR) can be performed under general anesthesia, regional anesthesia, total intravenous anesthesia (TIVA) or local anesthesia with conscious sedation. The type of anesthesia used is often one of surgeon preference, but multiple studies have shown a benefit to limiting the use of general anesthesia, when possible [35-37]. Local anesthesia is associated with shorter operating times, shorter hospital stays and fewer complications. If the cooperation level of the patient is anticipated to be poor, general anesthesia may be preferred to limit patient movement to allow accurate graft positioning.

Vascular access: Bilateral femoral access is needed to place endografts. Endovascular repair of AAA can be performed via surgical femoral cutdown or percutaneously. The cutdown approach is similar to that used for femoral embolectomy or femoral graft placement; however, in patients with a limited amount of atherosclerotic disease and no evidence for femoral aneurysm, exposure can be limited to the area of the common femoral artery that will be punctured. The incision can be longitudinal or transverse, but if patch repair of the common femoral artery is anticipated a longitudinal incision is preferred.

Open access can be more challenging in obese patients or in patients with prior groin surgery. Arteriotomy repair with a percutaneous suture device is feasible, even after the use of large-bore introducers [8,38-40]. In determining whether an artery is suitable for use with a percutaneous arterial closure device, several factors are important, including the size of the femoral artery, prior groin surgery or use of a closure device, significant arterial occlusive disease, and common femoral aneurysm.

Once the common femoral artery is accessed, deployment of the sheath into the anterior common femoral artery is critical. More proximal punctures through the inguinal ligament may cause problems with proper knot tying, and the proper application of pressure to achieve hemostasis may be more difficult. More distal access (eg, superficial femoral artery) can lead to vessel thrombosis.

 

Percutaneous access: Percutaneous access uses standard guidewire access and then uses progressive dilators to place the endograft sheath rather than direct exposure of the access vessel. Once the endograft is in place, closure of the defect in the vessel is accomplished using specialized vascular closure devices (eg, Perclose). The success rates of percutaneous endovascular aneurysm repair (EVAR) in various clinical studies approach 100 percent [8,38]. Variability in success appears to be related to the degree of femoral artery calcification and operator experience with the technique [40]. Sheath size and obesity do not appear to have a significant impact.

Iliac conduits: Small diameter access vessels increase the technical difficulty of EVAR, particularly in the setting of vessel calcification and tortuosity. Severe vascular stenoses or occlusions of the iliac arteries (TASC C and D lesions) increase the risk of a major iliac vessel complication and are an independent predictor of procedural failure [41]. Iliac rupture is a potentially fatal complication that appears to be more common in women, likely related to the generally smaller caliber of iliac artery [42].

Small caliber iliac vessels can be handled in a step-wise fashion. The initial approach is stretching the artery using graduated dilators or focal balloon angioplasty, as needed. If these maneuvers are not successful, the stent-graft can be delivered through an iliac conduit, which is a graft (eg, Dacron, expanded polytetrafluoroethylene [ePTFE]) that is sutured to the common iliac artery or distal aorta. The need for an iliac conduit should be anticipated based upon preoperative imaging. After providing adequate exposure of the pelvic vasculature through a low retroperitoneal incision, the iliac conduit is sutured into place, and the sheath inserted into the conduit (picture 1). To provide a less acute angle to pass the endograft, the iliac conduit can be passed through a subcutaneous tunnel under the inguinal ligament into the groin region before placing the sheath.
An alternative technique is termed an internal endoconduit. A covered stent is deployed within the iliac artery, and the endovascular sheath is subsequently passed from a common femoral artery access site; an adequately-sized femoral artery is a prerequisite for this technique. Any disruption of the iliac artery during passage of the sheath is contained by the covered stent [43]. Unexplained hemodynamic instability may indicate avulsion of the iliac artery. This technique can be useful in patients with a hostile retroperitoneum or colostomy, which can complicate the placement of an open iliac conduit.

Graft deployment: Once vascular access is established and landmarks for positioning the device are obtained with aortography, the main device is positioned with particular attention paid to the location of the opening for the contralateral iliac limb (“contralateral gate”). The aortic neck is imaged; a slight degree of craniocaudal and left anterior oblique angulation may improve imaging of the renal ostia. With the proximal radiopaque markers of the graft positioned appropriately below the lowest renal artery, the body of the graft is deployed to the level of the contralateral gate.

A guidewire is advanced through the contralateral access site into the contralateral gate. Gate cannulation is confirmed by placing a pigtail catheter over the guidewire into the main body of the graft, removing the guidewire and confirming that the pigtail catheter rotates freely within the main body of the graft; if it does not, the catheter is assumed to be in the aneurysm sac. Once the contralateral guidewire is positioned within the main body of the endograft, the deployment of the endograft at the neck of the aneurysm is completed followed by deployment of the contralateral, then ipsilateral iliac artery limbs (depending on the type of graft). Once the endograft components are in place, the attachment sites and endograft junctions are gently angioplastied with a compliant or semi-compliant balloon.

Completion aortography is performed to evaluate the patency of the renal arteries and evaluate for endoleak. Guidewire access is maintained throughout the procedure but is particularly important when removing the main graft body device sheath since disruption of the access vessels by an oversized sheath may not become apparent until after sheath has been removed.

Troubleshooting

Gate cannulation: Deployment of the main body of the device with the gate low in the aneurysm sac or below the aortic bifurcation can lead to a situation in which the contralateral gate does not open up when the device is deployed. This is referred to as “jailing the contralateral gate.” In some cases, pushing the device upward will allow the gate to flare open. Many currently available endovascular graft devices allow recapture of the graft to reorient the gate opening. If the gate of the graft cannot be moved more superiorly, conversion to an aortouniiliac (AUI) configuration or open conversion may be needed.

Even with correctly positioned grafts, it is not uncommon to encounter difficulties with gate cannulation, particularly with large aneurysm sacs that have minimal mural thrombus. Catheters with reverse angulation (eg, Vansche catheter, Cook Inc) can help engage the gate. If various types of catheters do help the wire pass through the gate, a wire can be passed up and over the graft flow divider from the ipsilateral to contralateral femoral access, or alternatively from an access site in the arm antegrade down through the gate. The antegrade wire can then be snared and pulled through the contralateral femoral access sheath.

Handling endoleak: Endoleak is a term that describes the presence of persistent flow of blood into the aneurysm sac after device placement, indicating failure to completely exclude the aneurysm from the aortic circulation [44]. Type I and type III endoleak identified at the time of endograft placement are repaired and generally respond to additional ballooning or the placement of additional endograft components. Open conversion is almost never required. Type II and type IV do not require any specific intervention when identified at the time of endograft placement.

Five types of endoleaks are described (figure 6) [45]:
– Type I endoleak is due to an incompetent seal at the proximal (Ia) or distal (Ib) attachment sites [45,46]. Etiologies include under-sizing of the diameter of the endograft or ineffective attachment of the endograft to a vessel wall that is heavily calcified or surrounded by thick thrombus. Type I endoleak is associated with significant pressure elevation in the aneurysm sac and has been linked to an ongoing risk of rupture [32,33]. All type I endoleaks should be corrected promptly, as spontaneous resolution, though possible, is not typical, and treatment can usually be accomplished by endovascular means. The initial treatment of procedural type I endoleak typically involves re-ballooning of the distal attachment sites, but placement of additional aortic cuffs, iliac limb extensions, or balloon expandable stent (eg, Palmaz) (image 4) is sometimes required. Open conversion is almost never required at the time of EVAR, but is sometimes needed for delayed type I endoleak.
– Type II endoleaks (picture 2) are caused by flow into and out of the aneurysm sac from patent branch vessels (eg, lumbar arteries, inferior mesenteric artery) [45]. The incidence of type II leak has been correlated with the number of patent aortic branches prior to endograft placement. Type II endoleaks are the most frequent type, occurring in 10 to 25 percent of endovascular aortic aneurysm repairs [46].
– Type III endoleaks (image 5) represent flow into the aneurysm sac due to separation of the components of the modular graft system (IIIA), or tears in the endograft fabric (IIIB). Type III endoleaks are as serious as type I endoleaks because they pressurize the aneurysm sac. As with type I endoleaks, the treatment usually involves deployment of additional stent graft components to seal the fabric defect or bridge disjoined modular components.
– Type IV endoleak is due to egress of blood through the pores of the fabric and typically resolves in 24 hours. It has not been associated with any long-term adverse events and does not require any treatment. It can, however, be quite disconcerting to see at completion aortography, because it often obscures the more serious type I or III leaks.
– Type V endoleak occurs in the postoperative period as continued aneurysm sac expansion without a demonstrable leak on any imaging modality. These are not apparent at the time of initial graft placement

POSTOPERATIVE CARE: Following endovascular repair of abdominal aortic aneurysm, patients can be transferred to a regular floor once they have recovered from anesthesia. The patient can drink clear fluids and advance to a regular diet, as tolerated. Treatment of acute postoperative pain consists mainly of nonsteroidal antiinflammatory drugs (NSAIDs) and/or opioids. (See “Management of postoperative pain”.)

Ambulation is resumed on the first postoperative day. The majority of patients can be discharged home within 24 hours following EVAR, provided no complications have occurred. Fluid therapy is continued to minimize the risk of contrast nephropathy, particularly in patients with preoperative renal insufficiency. (See ‘Prevention of contrast-induced nephropathy’ above.)

The peripheral pulse exam should be assessed at regular intervals and compared with the baseline preoperative examination. Any abnormalities should prompt duplex evaluation for potential endograft limb complications. (See “Complications of endovascular abdominal aortic repair”, section on ‘Extremity ischemia’.)

Endograft surveillance: Failure of aortic endografts is well documented and can lead to continued aneurysm expansion and potential rupture. Thus, it is mandatory for all patients to undergo routine surveillance to assure the integrity of the repair. The principle concerns are endoleak, aneurysm sac enlargement, migration of the stents at the aortic and iliac landing zones, and separation of the device components. The most commonly used imaging modalities for ongoing endograft surveillance are contrast-enhanced computed tomographic (CT) arteriography and duplex ultrasonography (DU). Other surveillance modalities include magnetic resonance (MR) imaging and aneurysm sac pressure measurements.

Abdominal plain films are an economical and quick way to evaluate the integrity of the metallic structure of the graft and endograft alignment, and can be obtained prior to discharge from the hospital.

CT angiography with delayed images is the most widely used modality for follow-up after endovascular aneurysm repair (EVAR). It is accurate for maximal diameter measurement, and for the detection of endoleak (image 6) and other device-related complications [47-52]. However, CT angiography is costly and repeated radiation exposure is associated with an increased lifetime cancer risk [47]. Repeated administration of intravenous contrast may also contribute to a progressive decline in renal function that has been observed following EVAR [53,54]. The guidelines for the management of abdominal aortic aneurysm (AAA) from the Society for Vascular Surgery advocate CT angiography at 1 and 12 months during the first year after EVAR. Imaging at six months is no longer routinely recommended unless an endoleak or other device-related abnormality is identified at the one-month imaging study after EVAR [32]. If an endoleak or aneurysm enlargement is not documented during the first year after EVAR, DU is an alternative to CT angiography for ongoing postoperative surveillance.

DU and unenhanced CT scan are acceptable alternatives to avoid intravenous contrast load and repeated exposure to radiation associated with repeated CT angiography. An advantage of DU is that it is noninvasive and less expensive compared with CT angiography, but DU needs to be performed by a skilled technician in an appropriately credentialed laboratory. Several studies have established the efficacy of DU, and its ability to detect endoleaks and evaluate sac expansion [55-67]. However, some speculate a lower sensitivity of unenhanced ultrasound for diagnosis of endoleak, which has led to increasing interest in contrast-enhanced ultrasound imaging [50]. Systematic reviews have found a pooled sensitivity and specificity of contrast-enhanced ultrasound for detecting any type of endoleak to be 96 to 98 percent, and 85 to 88 percent, respectively, using contrast-enhanced CT angiography as the diagnostic standard [64,65]. In comparing contrast-enhanced ultrasound to unenhanced ultrasound for all types of endoleak, contrast-enhanced ultrasound had a greater sensitivity but lower specificity than unenhanced ultrasound; however, for only type I and type III leaks, no differences were found [65]. This appears to suggest that the greater sensitivity of contrast-enhanced ultrasound compared with unenhanced ultrasound is related to identifying type 2 endoleak, for which the need for intervention is less certain.

MR imaging is not a standard modality for EVAR surveillance, but can be used in specific situations where CT angiography is contraindicated [32,33]. The advantage of MR imaging is the lack of exposure to ionizing radiation. Disadvantages are its lack of wide availability and difficulty evaluating device integrity due to artifact. The placement of stent-grafts made of nitinol does not preclude MR imaging, though MR imaging is contraindicated for stainless-steel-based grafts (eg, Cook, Zenith) (table 1).

Direct measurement of the pressure within the aneurysm sac after EVAR can be performed and is a reliable indicator of intra-sac pressure, but is invasive. Noninvasive aneurysm sac pressure measurements using implantable wireless pressure sensing systems have been developed, but accuracy may be limited by the presence of mural thrombus [68]. For type II endoleaks of unclear clinical significance, the sensor may assist in therapeutic management. However, remote pressure sensing does not provide any information about device integrity and these devices are unlikely to be used as stand-alone surveillance after EVAR, but may complement other low-risk modalities such as DU imaging.

Digital subtraction arteriography is reserved for the evaluation of specific problems such as decreased limb flow, graft limb thrombosis, documented endoleak, or to measure aneurysm sac pressure when an enlarging aneurysm is identified in the absence of an endoleak [69].

PERIOPERATIVE MORBIDITY AND MORTALITY: The overall complication rate for endovascular aneurysm repair, including access-related issues, is approximately 10 percent. The complications associated with endovascular aneurysm repair are discussed in detail separately. (See “Complications of endovascular abdominal aortic repair”.)

Device-related complications may include vascular injury as a result of device deployment and endoleak. Following successful endograft repair, the aneurysm sac will eventually thrombose, and the sac of most aneurysms progressively shrinks. The endograft repair may respond to the changing configuration of the aneurysm which can lead to late endograft complications such as angulation, kinking, thrombosis, or migration. Thus, lifetime endograft surveillance is required. (See ‘Endograft surveillance’ above.)

The short-term technical success rate for endovascular aneurysm repair has improved with increasing experience with the technique [16]. Technical failures may be due to a vascular complication or inability to resolve a type I leak. Open conversion at the time of repair is uncommon and is required in fewer than 2 percent of patients [70-72]. Thirty-day technical success rates range from 77 to 100 percent [73,74].

A systematic review identified four trials that included 1532 patients who were considered suitable candidates for endovascular or open repair of nonruptured abdominal aortic aneurysms larger than 5.0 cm in diameter [74]. The 30-day all-cause mortality was significantly lower with endovascular repair (1.6 versus 4.8 percent). The short-term survival advantage of endovascular repair appears to be much greater when endovascular repair is limited to patients at highest risk for open surgery. This was illustrated in a report of 454 consecutive patients who underwent elective repair (206 endovascular and 248 open surgeries) of an abdominal aortic aneurysm [75]. The overall 30-day mortality rates did not significantly differ for endografting and surgery (2.4 and 4.8 percent, respectively). However, among patients at highest surgical risk (American Society of Anesthesiologists [ASA] class IV), the 30-day mortality rates were lower for endovascular compared with open repair (4.7 versus 19.2 percent).

Using the United States Medicare database, long-term survival was evaluated in 22,830 matched pairs of patients who underwent elective repair with an open or endovascular technique between 2001 and 2004 [72]. There was a significantly lower rate of perioperative mortality with endovascular repair (1.2 versus 4.8 percent); a more pronounced benefit was seen with increasing age. However, as seen with other studies, overall mortality at three to four years following repair was nearly identical in the two groups.

Over the long-term, however, it has not been definitively established that endovascular repair is superior to open surgical repair, even among patients at highest risk for surgery. Although a 3 percent reduction in aneurysm-related mortality persisted throughout the follow-up period, in both the DREAM and EVAR1 trials, the initial reduction in all-cause mortality was eliminated within one to two years with equivalent overall survival in both treatment groups. A later analysis from the Medicare database of 4529 patients treated between 2003 and 2007 and followed over a median of 2.4 years found similar results in the perioperative period [76]. Aneurysm-related mortality and perioperative (30-day) mortality were reduced in the endovascular group. Among patients who survived longer >30 days, no difference in all-cause mortality was seen (HR 1.01, 95% CI 0.84-1.22). However, in this study, the survival advantage conferred with endovascular repair was maintained throughout the study period such that the all-cause mortality risk for open repair relative to endovascular repair remained elevated (hazard ratio [HR] 1.24, 95% CI 1.05-1.47). The average age of the patients who underwent endovascular repair was not significantly different compared with those treated with open repair (75 versus 76). (See “Management of asymptomatic abdominal aortic aneurysm”, section on ‘Open versus endovascular aneurysm repair’.)

INFORMATION FOR PATIENTS: UpToDate offers two types of patient education materials, “The Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)
– Basics topic (see “Patient information: Endovascular surgery (The Basics)”)
– Beyond the Basics topic (see “Patient information: Abdominal aortic aneurysm (Beyond the Basics)”).

SUMMARY AND RECOMMENDATIONS
– The abdominal aorta is defined as aneurysmal when a localized dilation is identified, and the diameter of that region is increased more than 50 percent relative to normal aortic diameter. For most individuals, an aortic diameter greater than 3.0 cm is generally considered aneurysmal. (See ‘Introduction’ above.)
– Endovascular repair of abdominal aortic aneurysm (EVAR) represents a widely available alternative to open surgical repair. However, the precise role of EVAR continues to be defined. Guidelines from major medical and surgical societies recommend an individualized approach to the patient when choosing between open and endovascular repair, taking into account the patient’s age, risk factors for perioperative morbidity and mortality, anatomic factors, and the experience of the surgeon. (See “Management of asymptomatic abdominal aortic aneurysm”, section on ‘Open versus endovascular aneurysm repair’.)
– The preprocedural evaluation of patients undergoing endovascular repair requires medical risk assessment and a careful quantitative and qualitative evaluation of aortoiliac anatomy to determine suitability for endovascular repair. With early endograft designs, about 50 percent of patients were not candidates for EVAR because of the site, extent, or morphology of the aneurysm, or unsuitability of access vessels. The availability of devices that allow a shorter proximal seal zone and lower profile devices have expanded the use of EVAR to almost two-thirds of patients with an infrarenal AAA. (See ‘Anatomic suitability’ above.)
– Endograft imaging is mandatory for the remainder of the patient’s life to evaluate endograft integrity and positioning. We use a combination of plain abdominal radiographs which can evaluate the metal stent structure, computed tomography and duplex ultrasonography to assess the graft at initial postoperative follow-up and then 1, 6, and 12 months postoperatively, and annually thereafter. (See ‘Postoperative care’ above.)
– Currently available endovascular grafts for infrarenal aortic repair share a bifurcated, modular design. There are no clear advantages of one design over another. The endovascular graft is constructed by the sequential delivery and deployment of device components in vivo. (See ‘Endografts’ above and ‘Endograft placement’ above.)
– Short-term mortality rates for endovascular therapy compare favorably with open surgical repair in randomized trials and large observational studies. The benefit is greatest for patients at highest surgical risk in whom the short-term mortality for endovascular repair is significantly lower compared with open repair (4.7 versus 19.2 percent at 30 days, in one report). It has not been definitively established that endovascular repair is superior to open surgical repair in the long term, even among patients at highest risk for surgery. (See ‘Perioperative morbidity and mortality’ above and “Management of asymptomatic abdominal aortic aneurysm”, section on ‘Open versus endovascular aneurysm repair’.)
– The overall complication rate for endovascular aneurysm repair, including access-related issues, is approximately 10 percent. Technical failures may be due to complications or the inability to resolve a type I leak, but these can usually be managed using adjunctive endovascular procedures. Open conversion may be required, but is uncommon, occurring in fewer than 2 percent of patients at the time of repair. Device-related complications include vascular injury as a result of device deployment and endoleak. (See ‘Perioperative morbidity and mortality’ above and “Complications of endovascular abdominal aortic repair”.)

INTRODUCTION: Thoracic endovascular aneurysm repair (TEVAR) refers to the percutaneous placement of a stent graft in the descending thoracic or thoracoabdominal aorta to improve long-term survival in patients with aortic aneurysms. The complications of elective thoracic aneurysm repair using an open surgical (OS) technique are higher than most elective surgical procedures, given anatomic constraints and operative complexity. TEVAR was initially developed to treat patients who were considered to not be surgical candidates but is now considered a suitable alternative to OS in most cases [1,2].

Potential benefits of TEVAR relative to OS include avoidance of long incisions in the thorax or abdomen, no cross-clamping of the aorta, less blood loss, lower incidence of visceral, renal, and spinal cord ischemia (SCI), fewer episodes of respiratory dependency, and quicker recovery [3].

The pivotal trials of TEVAR for treatment of thoracic aortic aneurysm led to its approval by the United States Food and Drug Administration in 2005 [1,4-7]. TEVAR has been increasingly used for other aortic pathologies such as complicated type B dissection, traumatic aortic transection, and aneurysmal disease extending into the arch. Each will be mentioned in brief, but this topic will principally address the endovascular treatment of thoracic aneurysms.

Issues related to etiology, clinical presentation, and diagnosis, as well as the medical and surgical management of thoracic aneurysmal disease, are discussed separately. (See “Clinical features and diagnosis of thoracic aortic aneurysm” and “Management and outcome of thoracic aortic aneurysm”.)

INDICATIONS FOR TEVAR: The indications for TEVAR of the descending aorta are similar to those for surgical repair and include width >6 cm, rapidly enlarging diameter (>5 mm of growth over six months), symptoms such as chest pain, and diagnosis of aortic rupture or dissection. (See “Management and outcome of thoracic aortic aneurysm”.)

This issue of whether to choose TEVAR or OS is discussed below. (See ‘TEVAR versus open surgery’ below and “Management and outcome of thoracic aortic aneurysm”.)

PREOPERATIVE PLANNING: Computed tomography angiography (CTA) of the chest, abdomen and pelvis with 3-D reformatting is performed preoperatively. It provides accurate information regarding the external and endoluminal diameter of the aorta to be used for the proximal and distal seal zones, the length of coverage required, the degree of angulation and tortuosity of the aorta, identification of important side branches, as well as characteristics of the lumen and wall of the aorta, including thrombus burden and calcification. From this information, the diameter and length of the graft(s) are chosen.

Additionally, the diameter of the external iliacs and the degree of calcification/tortuosity from the femoral vessels, through the iliacs, to the aortic bifurcation need to be noted, and a decision should be made whether to proceed with transfemoral or alternative access. (See ‘Conduct of the operation’ below.)

Magnetic resonance angiography (MRA) can also be used, but the degree of anatomical detailing is no better, and the risk of nephrogenic systemic fibrosis in patients with ESRD or chronic renal insufficiency affords no benefit compared to CTA [8]. MRA also fails to depict vessel wall calcification, which has implications for vascular access.

CONDUCT OF THE OPERATION: The procedure is typically done under general endotracheal anesthesia. A lumbar drain is placed in the L3-L4 disc space for drainage of cerebrospinal fluid (CSF) in cases where extensive coverage of the thoracic aorta is anticipated, where interruption of contributing blood supply to the artery of Adamkiewicz (T8-L1) is high, and in cases where the patient has had prior abdominal aortic aneurysm (AAA) repair. The artery of Adamkiewicz (Arteria Radicularis Magna) is the chief contributor to the anterior spinal artery in the thoracolumbar segment of the spinal cord. Therefore, deployment of a stent graft in this segment of the aorta may exclude blood flow from major contributors of spinal cord perfusion. A prior endograft in the abdominal aorta would cover the orifices of lumbar arteries which likewise contribute to spinal cord perfusion. Lumbar drainage of cerebrospinal fluid to decrease the pressure in the subarachnoid space and increase the spinal cord perfusion pressure (spinal cord perfusion pressure = mean arterial pressure-CSF pressure) is an important adjunct in preventing paraplegia (spinal cord ischemia) following TEVAR [9,10]. (See ‘Spinal cord ischemia’ below.)

Performance of the procedure requires the delivery of a large-bore sheath into the aorta as well as angiographic access. This is typically accomplished transfemorally, although patients presenting with disadvantaged femoral access sites may require delivery of the sheath through the common iliac artery, an iliac conduit, or an endovascular stent graft in the external iliac artery.

Anatomic considerations: The thoracic aorta is of larger caliber than that of the infrarenal abdominal aorta, which necessitates the usage of larger diameter stent grafts than those used for AAA repair. Thoracic grafts are housed in large sheaths, which sometimes preclude conventional transfemoral access and require delivery through the distal common iliac artery, creation of an iliac artery conduit, and, at times, direct delivery through the abdominal aorta.

In addition, the high force of blood flow in the thoracic aorta requires a longer seal zone (20 mm), defined as to either the proximal or distal ends of the thoracic stent graft where it is opposed to relatively normal aorta, on either end (compared with the abdominal aorta) to prevent displacement. The curve of the thoracic aorta at the arch presents special challenges in attempting to achieve adequate proximal fixation and seal. Radial support, defined as the ability to withstand external compression, must be weighed against the need for enough flexibility and conformability within the device in order to navigate this curve and achieve seal following deployment. The angulation of the aorta often progresses with age, as atherosclerotic changes lead to lengthening and increased tortuosity, adding to the difficulty of accurate device deployment and adequate proximal landing. (See ‘Proximal and distal landing zones’ below.)

When device deployment is performed close to or within the arch, the graft must closely appose the “inner curve” of the arch (figure 1). If the proximal end of the graft is oriented towards the apex of such a curve, “bird-beaking” where the graft is not apposed to the aortic wall will occur, increasing the risk of graft collapse, migration, and failure of aneurysm exclusion. With adequate preoperative planning, landing more proximally and debranching the arch as needed can usually circumvent these issues.

Proximal and distal landing zones: Placement of the proximal or distal end of the device may require covering important side branches. “Hybrid” procedures which combine open vascular bypass to important vessels followed by thoracic stent grafting have been developed [11].

The proximal seal zone, also referred to as the landing zone, may abut or involve branch vessels of the arch, namely the brachiocephalic trunk, left common carotid artery, and left subclavian artery. In order to achieve the 20 mm proximal seal required and ensure that the graft will sit in close apposition to the inner curve of the arch, debranching procedures using “hybrid” techniques can be performed, which essentially “move” the branch vessels to a more proximal location, allowing coverage of the origins of these vessels [11]. When coverage of the left subclavian artery is required, duplex of the vertebral and carotid arteries should be completed to determine whether left common carotid-left subclavian bypass or left subclavian transposition is in order.

For more proximal landing zones involving the left common carotid artery or brachiocephalic trunk, antegrade bypass from the ascending aorta/transposition of the great vessels can be performed or, alternatively, extraanatomic bypass can be performed to avoid sternotomy [12-15].

The distal seal zone also must be at least 20 mm in length. Typically, the celiac axis is spared. Reports of covering the celiac artery in patients with a documented patent pancreaticoduodenal arcade have been successful in achieving up to an additional 25 mm in seal length with nominal incidence of mesenteric ischemia [16,17]. Once the device is deployed, the stent graft is typically ballooned at the seal zones and graft junctions.

On occasion the distal end of a thoracoabdominal aneurysm may extend below the level of the renal arteries blood flow, and intercostal, visceral and renal arteries may be compromised. Surgical and stenting techniques have been developed to decrease the likelihood of this complication [11].

Endoleak: Repeat angiography is performed at the conclusion of the procedure to ensure effective sac exclusion, preservation of essential vessels, and to detect any evidence of endoleak. An endoleak is the persistent flow in the aneurysm sac following endovascular repair of the aorta. There are five types:
– Type I endoleak: Involves the proximal or distal seal zones. Further ballooning or placement of another graft may be necessary to achieve seal. Vigorous proximal ballooning may be hazardous; retrograde proximal aortic dissection has been reported.
– Type II endoleak: Unusual in the thoracic aorta but due to retrograde flow from intercostal arteries into the sac. Typically resolves with observation
– Type III endoleak: Occurs with inadequate overlap and seal between modular components. Usually responds with further ballooning or additional graft or stent placement.
– Type IV endoleak: Occurs due to porosity of the graft, which is a rare occurrence with current generation devices.
– Type V endoleak: Otherwise known as “endotension,” occurs in the setting of continued sac expansion despite absence of an identifiable endoleak on subsequent imaging studies.

Once exclusion of the sac has been confirmed, the device sheath is removed, and the arteriotomy is repaired.

Devices: The following devices are currently approved or under investigation for treatment of descending thoracic aneurysms [18]:
– The Gore-TAG device is made of e-polytetrafluoroethylene and an exoskeleton made of nitinol. The proximal and distal ends of the graft have scalloped flares, which are thought to allow for conformity and better apposition to the tortuous aorta.
– The Medtronic Talent thoracic stent graft system was studied in the VALOR I trial, which proved its clinical efficacy. It is made of two components, a proximal straight tubular stent graft with a proximal bare stent configuration and a distal tapered tubular stent graft with an open web proximal configuration and closed web distal configuration. It consists of a woven polyester graft with a nitinol endoskeleton.
– The Medtronic Valiant endograft has a modified proximal bare stent configuration with eight bare peak wires compared with the five bare peak wires found in the Talent stent graft. The long connecting bar of the Talent device was removed in the Valiant device to afford better flexibility of the device.
– The Cook TX2 stent graft is a two-piece modular endograft system made of proximal and distal tubular endografts. The proximal endograft is covered and has stainless steel barbs, allowing for active fixation to the aortic wall. The distal component has at its distal end a bare metal stent similar to the suprarenal stent in the Zenith device for endovascular repair of AAA. This allows active fixation of the device over the origins of the visceral vessels. The TX2 is made of Dacron fabric covered by stainless steel Z-stents.
– The Bolton Relay stent graft is an investigational device used for the treatment of thoracic aortic pathologies. It is composed of self-expanding nitinol stents sutured to a polyester fabric graft with a curved longitudinal nitinol wire intended to provide columnar strength. It has a proximal bare stent, which remains constrained until the endograft is fully deployed. The pivotal study is underway.

OUTCOMES: Patients with thoracic aneurysms have a poor prognosis, particularly if they are large or expanding. (See “Management and outcome of thoracic aortic aneurysm”.)

In patients who meet criteria for OS, survival is improved with OS compared to medical therapy. (See “Management and outcome of thoracic aortic aneurysm”, section on ‘Morbidity and mortality’ and “Management and outcome of thoracic aortic aneurysm”.)

While little comparative data exists between TEVAR and medical management, it is reasonable to assume that outcomes will also be better with TEVAR in those patients with indications for OS, since TEVAR compares favorably with OS.

The outcomes presented below suggest that TEVAR is a promising alternative to open surgical (OS) repair [1,6,7].

Combined perioperative outcomes: In a study where perioperative morbid events including myocardial infarction, respiratory events such as pneumonia or ventilation for more than 24 hours, stroke and paraplegia were combined into a composite score, the percentage of patients who experienced at least one event was significantly lower in the TEVAR group compared to the OS arm (9 percent versus 33 percent) [1].

Stroke: Because the proximal seal zone is in proximity to the carotid arteries, embolic strokes can occur following TEVAR. Risk factors for embolic stroke include the need for proximal deployment of the graft, presence of mobile atheromata in the arch, and prior stroke [19]. The vertebral arteries arising from the subclavian may be the source for posterior circulation strokes [20]. Perioperative stroke has ranged from 4 percent to 8 percent [21-23], comparable to OS [24].

As described earlier, preoperative planning consists of carotid and vertebral artery duplex, sometimes with a CTA of the head and neck. Planned coverage of the left subclavian in a patient with a dominant left vertebral, hypoplastic right vertebral, or incomplete circle of Willis should be preceded by carotid subclavian bypass, as interruption of blood flow in these circumstances has been associated with an increased incidence of stroke and paraplegia [20,25,26]. Left upper extremity symptoms, while occurring in up to 15.8 percent of patients in one study, only required intervention in a minority of patients (5.3 percent), supporting expectant management in the majority of cases [27].

Spinal cord ischemia: Extensive coverage of the thoracic aorta as well as prior history of AAA repair places the patient at increased risk for spinal cord ischemia (SCI) with the potential for paraplegia [28-30]. The risk of spinal cord ischemia has been reported to be between 3 to 11 percent [1,3,5,23,31], comparable to the rate of OS [24].

Some studies have demonstrated a lower rate of SCI with TEVAR than with OS. In a well-performed, retrospective review of 724 patients at a single institution who were treated with either TEVAR (n=352) or OS (n=372) for thoracic or thoracoabdominal aneurysms, no statistically significant difference in the rate of SCI was found between the two approaches (4.3 versus 7.5 percent respectively) [3]. The extent of aortic disease was the strongest predictor of SCI.

Visceral ischemia: Visceral ischemia can occur with coverage of the celiac axis. Although, reports have suggested that collateralization through an intact pancreaticoduodenal arcade allows for extension of the distal seal zone to the level of the superior mesenteric artery (SMA) without physiologic consequence [16]. Similarly, stenting to below the SMA or renal artery levels requires revascularization of these vessels, or use of specialized fenestrated grafts [32].

Access complications: Because of the obligatory large sheath size for delivery of the device, passage of the sheath through a small diameter, tortuous, or excessively calcified external iliac artery can lead to iliac artery disruption. Intra-aortic balloon control, using a balloon-mounted catheter introduced through the femoral or common iliac artery, helps to stabilize the patient until proximal and distal control of the iliac artery and definitive repair can be conducted. Anticipation of the need for adjunctive access measures is thus important and is required in a significant percentage of patients, ranging from 9.4 percent to 23.8 percent in published reports [1,7]. From the percutaneous angiography puncture site, a pseudoaneurysm or hematoma may form. (See “Periprocedural complications of percutaneous coronary intervention”, section on ‘Vascular complications’.)

Postimplantation syndrome: This syndrome occurs during the early postoperative period and is characterized by leukocytosis, fever, and elevation of inflammatory mediators such as C-reactive protein, IL-6, and TNF-alpha [33-35]. It is thought to be due to endothelial activation by the endoprosthesis. For thoracic aortic stent grafts, development of either unilateral or bilateral reactive pleural effusions is not uncommon, with a reported incidence of 37 percent to 73 percent [34,36,37].

Thirty day mortality: Perioperative mortality with second generation stent grafts is low, ranging from 1.9 percent to 2.1 percent [1,2,5]. Patients with emergent procedures and aortic dissection have a higher 30-day mortality rate [31]. (See ‘Emergency stenting’ below.)

Short-term: The largest published series, which has reported one year follow up, included 443 patients treated with endovascular stents for a variety of indications, both emergent and elective: thoracic aortic aneurysm (249 patients), thoracic aortic dissection (131 patients), traumatic aortic injury (50 patients) and false anastomotic aneurysm (13 patients) [31]. Approximately one-third of the procedures were emergent, and one-half of the patients were deemed high-risk and would not have been considered candidates for surgical repair. The following findings were reported:
– Technical success was achieved in 87 percent of patients with aortic aneurysm, and 89 percent of patients with aortic dissection.
– One year all cause mortality among patients treated for aortic aneurysm and aortic dissection were 20 and 10 percent respectively.

These results should not be compared directly to historical outcomes following surgical repair. Patients included in this series had a greater burden of comorbid disease and many would not have been candidates for surgery. The short duration of follow-up precludes direct comparison with the durable effects of successful surgical repair. (See ‘TEVAR versus open surgery’ below and “Management and outcome of thoracic aortic aneurysm”, section on ‘Morbidity and mortality’.)

Medium-term: The largest of the early series, for which there is now medium-term follow up, was a prospective, uncontrolled study of a first-generation, custom-fabricated self-expanding stent graft, including 103 patients with descending thoracic aortic aneurysms, 60 percent of whom were not candidates for conventional surgery [23].

After a 1.8 year follow up, the following findings were noted:
– Late stent graft complications occurred in 38 percent of patients and included stent graft misdeployment or removal, endoleak, aortic dissection, distal embolization, gut ischemia, and infection.
– Fatal complications occurred in 4 percent, including rupture of the treated aneurysm, stent graft erosion into the esophagus (aortoesophageal fistula), arterial injury, and excessive bleeding

In a subsequent report at 4.5 years of follow-up, actuarial survival at one, five and eight years was 82, 49, and 27 percent, respectively [21]. Patients who had been identified as suitable surgical candidates at the time of stent graft placement had significantly better survival at one year (93 versus 74 percent) and five years (78 versus 31 percent).

Device migration and endoleak: Migration of the graft (>10 mm) caudally can occur, with a published incidence of 1 percent to 2.8 percent over a 6 to 12 month period [1,2,5]. Factors predisposing to migration include excessive oversizing and tortuous seal zone anatomy.

The incidence of endoleak following thoracic aortic stent placement is less common than that for endoscopic repair of the abdominal aorta and is estimated at 3.9 percent to 15.3 percent [1,2,5,38]. The incidence of endoleak at five-year follow-up with the Gore TAG device was 4.3 percent with Type I attachment site leaks being the most common type. Ongoing surveillance for endoleak is necessary and discussed in the next section.

The rate of secondary intervention required following stent grafting due to either endoleak or device migration is 3.6 percent to 4.4 percent [1,2].

TEVAR versus open surgery: No randomized trials comparing TEVAR to open surgery (OS) have been published. The strength of the evidence from observational studies comparing TEVAR to OS is limited due to the following concerns [24]:
– Many studies compare TEVAR with older surgical techniques or operations with greater extents of repair.
– Many patients enrolled in TEVAR studies were not eligible for OS due to comorbidities.
– Many patients enrolled in OS studies include patients who would not be eligible for TEVAR because of anatomic constraints.

The best available evidence comes from a 2008 meta-analysis of 17 observational studies (1109 patients) which compared TEVAR to OS [39]. There was a significant reduction in perioperative mortality (OR 0.36; 95% CI 0.23-0.58) and in major neurological injury (OR 0.39; 95% CI 0.25-0.62). There was no difference in major reintervention rates, but a significant reduction in hospital and critical care stay. These benefits were seen predominantly in stable patients.

Nonrandomized comparisons published after the meta-analysis have suggested equivalent or better outcomes with the TEVAR:
– In a single center, retrospective study of over 700 patients who received either TEVAR or OS, mortality was not significantly different at 30 days (5.7 versus 8.3 percent respectively) and 12 months (15.6 versus 15.9 percent respectively) [3].
– In two smaller studies, each of which included around 230 patients, the perioperative mortality was lowered with TEVAR (2.1 versus 11.7 percent early after surgery, and 1.9 versus 5.7 percent at 30 days) [1,5].
– Patients in the first small study cited above were followed for five years [2]. Aneurysm-related mortality was lower for TEVAR (2.8 versus 11.7 percent) most of which was attributable to fewer perioperative deaths. MACE, defined as prolongation of treatment, new hospitalization, major disability, or death, was also lower (58 versus 79 percent). No significant difference in survival (68 versus 67 percent) or the rate of aneurysm related reintervention (3.6 versus 2.1 percent) was seen.

The evidence cited above argues for the use of TEVAR as opposed to OS in those patients who are candidates for both approaches. Even if patients’ important outcomes such as mortality, and the risks of stroke and paraplegia are equivalent, patients undergoing TEVAR have a shorter length of hospital stay, quicker rehabilitation, and a longer average number of months lived (due to a reduction in perioperative mortality).

Patients with thoracic aneurysm often have one or more significant comorbidities and both TEVAR and OS are extremely challenging procedures. Patients undergoing either procedure should be referred only to health care teams that are both experienced in the preoperative and intraoperative management of these patients.

EMERGENCY STENTING: The efficacy of stenting versus surgery in the emergent setting was specifically addressed in a nonrandomized study of 60 consecutive patients with acute rupture of the thoracic aorta; 28 patients were treated surgically and 32 were treated with an endovascular stent graft [40]. The following findings were reported:
– Perioperative mortality was significantly lower in the stented patients (3.1 versus 17.8 percent).
– At a mean follow-up of 36 months, four additional deaths occurred in stented patients, three of which were attributed to late procedural complications (one aneurysm, one dissection, and one traumatic transection). No additional procedure-related deaths occurred in the surgical patients.
– Reintervention rates were similar in the two groups. All of the surgical reinterventions were early reexplorations for bleeding. In the patients treated with stents, one required early drainage of an empyema and two required late interventions for endovascular leaks (one repeat stent, complicated by paraplegia; one surgical repair with stent removal).

OTHER POTENTIAL USES OF TEVAR: Because TEVAR is associated with a large reduction in perioperative morbidity and mortality compared to open repair, every effort is made to employ an endovascular strategy.

Traumatic aortic transection: Traumatic aortic transection typically occurs with high-speed, deceleration-type injuries and at the level of the ligamentum arteriosum. TEVAR has been associated with significantly lower morbidity and mortality compared to open repair in a younger trauma population [41] and in a 2008 meta-analysis [42]. No long-term data regarding the longevity of stent repair in this group are available.

Type B uncomplicated dissection: The INSTEAD trial (INvestigation of STEnt grafts in patients with type B Aortic Dissection) was a prospective, multicenter randomized trial comparing optimal medical therapy to endovascular stent graft placement for uncomplicated Type B dissection [43]. There was no significant difference in all-cause mortality at one year between groups. The preliminary conclusion of the trial was that careful monitoring and tailored antihypertensive therapy for these patients is justified. The one critique of the INSTEAD trial was that the study was designed to evaluate patients with more chronic dissections (56 days in stent graft group versus 75 days in the medical management group). The ADSORB study, currently underway in Europe, will compare best medical management to stent grafting for patients with uncomplicated type B dissection presenting <14 days after symptom onset.

Type B complicated dissection: Treatment of Type B dissection with malperfusion has been successfully treated endovascularly and consists of covering the primary entry tear and re-expanding the true lumen [44,45]. Assessment of the restoration of luminal flow to the true lumen can be performed with the use of IVUS (intravascular ultrasound), which offers real-time information regarding the true and false lumina throughout the cardiac cycle. (See “Clinical manifestations and diagnosis of aortic dissection”.)

Penetrating aortic ulcer/Intramural hematoma: These are lesions lying within the spectrum of aortic dissection pathology; treatment should consist of covering the intimal tear of any coexistent dissection, as well as exclusion of the aortic lesion. Although isolated penetrating ulcers are easy to cover with endovascular devices, it is unclear if extensive intramural hematoma is, in fact, a contraindication to this approach.

Thoracoabdominal aneurysms: Endovascular therapy of thoracoabdominal aneurysms is, thus, hindered by the presence of the intervening visceral segment. Hybrid approaches consisting of “debranching” procedures have been developed to provide separate blood flow to the visceral arteries and allow coverage of the visceral segment [46,47]. While debranching procedures are not without morbidity, they may be a suitable option in patients in whom avoiding a thoracotomy or cardiopulmonary bypass is appropriate [11].

LONG-TERM SURVEILLANCE: Computed tomography angiography is usually obtained within a month of the procedure, followed by an imaging study at six months and annually thereafter. Evidence of attachment site endoleak is intervened upon promptly. Type II endoleaks can be observed if the sac does not enlarge. Magnetic resonance angiography can also be used, although it is of limited applicability in patients with ESRD or CRI. Noncontrast computed tomography allows for measurement of the sac diameter and is sufficient in most circumstances to document effective aneurysm exclusion.

INFORMATION FOR PATIENTS: UpToDate offers two types of patient education materials, “The Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)
– Basics topic (see “Patient information: Endovascular surgery (The Basics)”)

SUMMARY AND RECOMMENDATIONS: For patients with indications for repair of thoracic aortic aneurysms, we suggest TEVAR instead of OS (Grade 2B). This recommendation is based upon the following points:
– Patients with thoracic or thoracoabdominal aortic aneurysm have a poor prognosis when they have the following indications for repair: width >6 cm, rapidly enlarging diameter (>5 mm of growth over six months), symptoms such as chest pain, or diagnosis of aortic rupture or dissection. (See ‘Indications for TEVAR’ above.)
– TEVAR, in patients with or without involvement of the abdominal aorta, has gained acceptance as a reasonable alternative to OS. While no randomized trial data is available to compare the two strategies, observational data suggests equivalent or better patient important outcomes with TEVAR. (See ‘TEVAR versus open surgery’ above.)
– Despite the significant rate of secondary intervention required following stent grafting (3.6 percent to 4.4 percent), the decreased morbidity of this approach makes it preferable to open repair in the majority of cases. (See ‘Medium-term’ above.)

The decision to perform TEVAR requires not only knowledge that the procedure is technically possible but that the patient’s general health makes it logical and feasible. (See ‘Conduct of the operation’ above and “Management and outcome of thoracic aortic aneurysm”.)

© 2014
go to top