Complications of endovascular aneurysm repair of the thoracic and abdominal aorta: evaluation and management

Abstract

In recent decades, endovascular aneurysm repair or endovascular aortic repair (EVAR) has become an acceptable alternative to open surgery for the treatment of thoracic and abdominal aortic aneurysms and other aortic pathologies such as the acute aortic syndromes (e.g., penetrating aortic ulcer, intramural hematoma, dissection). Available data suggest that endovascular repair is associated with lower perioperative 30-day all-cause mortality as well as a significant reduction in perioperative morbidity when compared to open surgery. Additionally, EVAR leads to decreased blood loss, eliminates the need for cross-clamping the aorta and has shorter recovery periods than traditional surgery. It is currently the preferred mode of treatment of thoracic and abdominal aortic aneurysms in a subset of patients who meet certain anatomic criteria conducive to endovascular repair. The main disadvantage of EVAR procedures is the high rate of post-procedural complications that often require secondary re-intervention. As a result, most authorities recommend lifelong imaging surveillance following repair. Available surveillance modalities include conventional radiography, computed tomography, magnetic resonance angiography, ultrasonography, nuclear imaging and conventional angiography, with computed tomography currently considered to be the gold standard for surveillance by most experts. Following endovascular abdominal aortic aneurysm (AAA) repair, the rate of complications is estimated to range between 16% and 30%. The complication rate is higher following thoracic EVAR (TEVAR) and is estimated to be as high as 38%. Common complications include both those related to the endograft device and systemic complications. Device-related complications include endoleaks, endograft migration or collapse, kinking and/or stenosis of an endograft limb and graft infection. Post-procedural systemic complications include end-organ ischemia, cerebrovascular and cardiovascular events and post-implantation syndrome. Secondary re-interventions are required in approximately 19% to 24% of cases following endovascular abdominal and thoracic aortic aneurysm repair respectively. Typically, most secondary reinterventions involve the use of percutaneous techniques such as placement of cuff extension devices, additional endograft components or stents, enhancement of endograft fixation, treatment of certain endoleaks using various embolization techniques and embolic agents and thrombolysis of occluded endograft components. Less commonly, surgical conversion and/or open surgical modification are required. In this article, we provide an overview of the most common complications that may occur following endovascular repair of thoracic and AAAs. We also summarize the current surveillance recommendations for detecting and evaluating these complications and discuss various current secondary re-intervention approaches that may typically be employed for treatment.

Keywords: Endovascular aneurysm (or aortic) repair (EVAR); abdominal aortic aneurysm (AAA); endograft; imaging surveillance; secondary endovascular interventions; thoracic endovascular aneurysm repair (TEVAR).

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

Figures

Figure 1

Treatment of a type IA endoleak. Intraprocedural DSA images show (A) a short and conical proximal neck in a patient undergoing EVAR. This is a known predisposing factor for a type IA endoleak; (B) following deployment of the endograft, contrast can be seen coursing outside of the confines of the device (arrow) filling the aneurysm sac, a finding that is typical of a type I endoleak; (C) in order to maximally distend the endograft device at the proximal attachment site, a high radial force balloon-mounted bare-metal Palmaz® stent (arrows) was deployed; (D) after placement of the additional stent, the endoleak has been eliminated, with only the endograft filling. DSA, digital subtraction angiography; EVAR, endovascular aneurysm (or aortic) repair.

Figure 2

Treatment of a type IB endoleak. Axial contrast-enhanced post-EVAR surveillance CT images show (A) a large collection of contrast (arrow) anteriorly within the residual AAA sac external to the endograft limbs that (B) courses inferiorly (arrow) adjacent to the right iliac limb of the graft; (C) 3D image again shows the endoleak (arrows) and also demonstrates that the distal aspect of the right iliac limb is flared (short arrow); (D) intraoperative DSA shows contrast tracking outside of the flared end of the right iliac limb (black arrow), a finding that is typical of a type IB endoleak; (E) intravascular coils (black arrows) were placed in the right internal iliac artery so as to prevent retrograde perfusion of the area of endoleak and an additional modular graft limb (white arrows) was extended into the external iliac artery to achieve a satisfactory distal seal; (F) 3D image following endoleak repair shows the final configuration of the right iliac limb as well as resolution of the endoleak. EVAR, endovascular aneurysm (or aortic) repair; AAA, abdominal aortic aneurysm; DSA, digital subtraction angiography; CT, computed tomography.

Figure 3

Treatment of a type II endoleak. Axial contrast-enhanced post-EVAR surveillance CT images show (A) a contrast-filled patent inferior mesenteric artery (IMA) (arrow) emanating from the residual AAA sac; (B) a contrast collection anterior (arrow) to the endograft fills via retrograde flow within the IMA, which is typical of a type II endoleak; (C) a 3D image shows that the middle colic artery (white arrow), arising from the superior mesenteric artery (SMA) fills the left colic artery of the IMA (black arrow) in retrograde fashion, thereby perfusing the endoleak nidus (short arrow). This course is highlighted in red; (D) intraoperative DSA shows the same vascular arcade (arrows) that fills the type II endoleak nidus; (E) a microcatheter (black arrows) has been passed through this SMA to IMA route and contrast has been injected opacifying the nidus (white arrow); (F) the endoleak has been embolized using Onyx®, with the large cast (black arrows) evident in the AAA sac. EVAR, endovascular aneurysm (or aortic) repair; AAA, abdominal aortic aneurysm; CT, computed tomography.

Figure 4

Translumbar treatment of a type II endoleak. Axial contrast-enhanced post-EVAR surveillance CT image shows (A) a contrast (arrow) anteriorly within the residual AAA sac external to the endograft limbs; (B) intraoperative right internal iliac DSA shows filling of the iliolumbar artery (short arrow) with retrograde perfusion of a lower lumbar artery (arrow); (C) a more delayed image shows faint opacification of the endoleak nidus (arrow) within the aneurysm sac; (D) via percutaneous translumbar access, a catheter (arrow) has been introduced directly into the residual AAA sac and contrast has been injected, opacifying the nidus (short arrow) and additional lumbar arteries; (E) a combination of intravascular coils and liquid thrombin were used to embolize the nidus. A filling defect (arrow) in the base of the nidus is seen where the initial embolic agents have been introduced; (F) final image after translumbar embolization shows elimination of the type II endoleak. DSA, digital subtraction angiography; EVAR, endovascular aneurysm (or aortic) repair; AAA, abdominal aortic aneurysm; CT, computed tomography.

Figure 5

Type III endoleak repair. (A) Intraoperative DSA shows complete separation of components of a modular endograft, with the proximal aortic cuff (short arrow) remaining in the original position but with detachment of the endograft body (arrow), with an intervening segment in which there is no endograft, so that the AAA sac is no longer excluded; (B) a new endograft component (arrow) has been introduced and will be used to bridge the separated endograft components; (C) after placement of the new component the integrity is restored (arrows). The new component extends proximally (short arrow) above the original aortic cuff; (D) the type III repair required extension of the new component via only one limb of the bifurcated body of the original endograft. Thus, in order to perfuse the contralateral lower extremity, placement of a cross femoral bypass graft (arrow) was necessary, as seen in this 3D CT image. DSA, digital subtraction angiography; AAA, abdominal aortic aneurysm; CT, computed tomography.

Figure 6

Endoleak following TEVAR. (A) 3D CTA image of the thoracoabdominal aorta prior to TEVAR shows a large bilobed descending thoracic aortic aneurysm; (B) the aneurysm was treated with placement of a thoracic endograft (arrows); (C) axial image from a surveillance CT shows a contrast collection (arrow) adjacent to the endograft, c/w an endoleak; (D) intraoperative DSA shows that the endoleak (arrows) is adjacent to overlapping modular components of the TEVAR endograft, indicating that this is a type III endoleak; (E) an additional endograft component was placed bridging the area from which the endoleak originates: prior to balloon distension of the new component the endoleak is still evident (arrows); (F) after distending the newly placed device component with a compliant balloon, the endoleak is eliminated. CTA, CT angiography; TEVAR, thoracic endovascular aneurysm repair; DSA, digital subtraction angiography; CT, computed tomography.

Figure 7

Endograft migration. (A) Lateral radiograph 1 month after EVAR shows the expected configuration of the endograft post-placement; (B) the intraoperative DSA at the time of endograft placement shows a typical endograft configuration; (C) a lateral radiograph obtained 2 years after EVAR shows that the endograft limbs are now bowed anteriorly. This change in the endograft configuration occurred as a result of remodeling of the residual aneurysm sac; (D) the distal ends of the iliac limbs have now migrated cephalad, resulting in type IB endoleak (arrows). EVAR, endovascular aneurysm (or aortic) repair; DSA, digital subtraction angiography.

Figure 8

Kinked endograft limbs. DSA shows kinked endograft limbs (arrows), a phenomenon that may occur in association with remodeling of the AAA sac following EVAR, and may lead to limb occlusion and thrombosis. DSA, digital subtraction angiography; AAA, abdominal aortic aneurysm; EVAR, endovascular aneurysm (or aortic) repair.

Figure 9

Bird-beak configuration of TEVAR endograft. There is imperfect apposition at proximal end of the thoracic endograft to the lesser curve of the thoracic aortic arch. This lack of apposition results in a wedge-shaped gap between the undersurface of the endograft (white arrow) and the aortic wall (black arrow). The bird-beak configuration is significantly correlated with the risk of type IA endoleak formation, and it is a potential risk factor for proximal endograft collapse or infolding. TEVAR, thoracic endovascular aneurysm repair.