Endoleaks in Abdominal Aortic Aneurysm Endoprosthesis: What radiologists need to know about Diagnostic, Characterization and Basic Management Strategies Poster No.: C-0150 Congress: ECR 2013 Type: Educational Exhibit Authors: M. E. Salazar Salazar, C. Carballo Fernandez, F. Romero 1 2 1 2 2 Cique, J. P. Giraldo Marin, Y. Arias Morales, A. Abu-Suboh 2 1 2 Abadia ; Orense/ES, Ourense/ES Keywords: Vascular, Arteries / Aorta DOI: 10.1594/ecr2013/C-0150 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 45
Learning objectives Describe and illustrate the most significant radiological findings present in the different types endoleaks. This complication is one of the most common procedures after prosthetic repair of abdominal aortic aneurysms. Understand the basic principles of management of each type of endoleak according to their classification. Background Abdominal Aorta Aneurysm (AAA) is a life-threatening condition that is present in 2-4% of the population over 50 years, being the average age at the time of diagnosis of 65-70 years. It is more common in men than in women and is usually secondary to atherosclerosis, but can also be caused by trauma and infection. Both open surgery and endovascular repairement (EVAR) is available for its handling. EVAR was developed by Parodi in 1990 and consists of inserting a prosthesis through the femoral arteries, and anchoring it to the proximal and distal ends of the non aneurysmal portion of the artery the AAA is excluded from the circulation, thus avoiding laparotomy and preventing the risk of growth and rupture of the aneurysm. This technique has been perfected and has rapidly become an alternative for patients who have a compatible anatomy, especially if they are considered high-risk patients for conventional surgery. However, with the increasing use of this technique, the frequency of complications has increased too. Endoleaks are one of the most frequent complications (20-25%) and may progress to the rupture of the aneurysm. The term endoleak is defined as an outflow of blood inside of the excluded aneurysmal sac after the placement of the prosthesis. Page 2 of 45
It has been developed a classification system which describes both the cause of the leak and recommended management according to its kind, been the last one both a conservative or urgent. Table 1 References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES For a correct evaluation of the abdominal aorta and detection of possible endoleaks in tomographic studies a protocol must be followed that includes 3 phases: a phase without contrast, an arterial phase and a late phase after 90 seconds. Images for this section: Page 3 of 45
Table 1 Page 4 of 45
Imaging findings OR Procedure details Type I Endoleak These occur when there is a leak of blood to the aneurysmal sac through one of the prosthesis s fixation sites. They are subdivided according to the location of the leak in type 1A when it is proximal (aortic end) and type 1B if it is distal (iliac end). In either of the two types, occurs a separation between the prosthesis and the native artery wall, creating a direct communication between the aneurysmal sac and the systemic blood circulation. Page 5 of 45
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Fig. 1: Type I endoleak: blood leakage from the prosthesis through one of the anchoring sites. References: Mustafa R. Bashir (2009) Endoleaks after endovascular abdominal aortic aneurysm repair: managment strategies according to CT findings. AJR:192 178-186 This type of endoleak is considered of high pressure since the aneurysmal sac is exposed to the aortic pressure and it has a high risk of rupture. It is frequently associated with a measurable increase in the size of the aneurysm. Findings CT scan of abdominal aorta: a hyperdense acute hemorrhage or a collection of extravasaded contrast into the aneurysmal sac, usually central, and in most cases in continuity with one of the sites of fixing. Fig. 2: 67 year old male patient with AAA treated with a biiliac stent graft. The abdominal aorta CT without contrast do not displayed hemorrhagic collections References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 7 of 45
Fig. 3: Abdominal aorta CT (arterial phase) of the same patient. There is a contrast active leakage at the distal end of the aortic stent, findings regarding of a type Ia endoleak. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 8 of 45
Fig. 4: Coronal reconstruction shows the contrast leakage into the aneurysm sac at the proximal level of the stent. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Treatment Page 9 of 45
They must be repaired immediately after being diagnosed since there is direct communication between the aneurysmal sac and the arterial blood under systemic pressure, they have a high risk of rupture. These leaks are corrected by making an anchor with balloon angioplasty or stents sites. The employment of embolization for these cases has also been described. Type II Endoleak They are the most frequent endoleak type and represent approximately 40% of the cases. Occurs by a retrograde blood flow to the aneurysmal SAC through the excluded aortic branches, being the lumbar and the inferior mesenteric arteries the most frequent sources. Page 10 of 45
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Fig. 5: Blood reflux into the aneurysm sac through collateral vessels, being the most frequent the lumbar or inferior mesenteric artery. References: Mustafa R. Bashir (2009) Endoleaks after endovascular abdominal aortic aneurysm repair: managment strategies according to CT findings. AJR:192 178-186 It is important the control of the growth of the aneurysmal sac since if it increases in size, there is a long - term increased risk of rupture. Findings CT scan of abdominal aorta: acute hemorrhage or presence of extravasated contrast of peripheral location within the aneurysmal sac. Fig. 6: 77 year old male patient with AAA and an aortobiiliac stent. Abdominal aorta CT without contrast shows no hemorrhagic collections. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 12 of 45
Fig. 7: Arterial phase abdominal aorta CT in the same patient where there is a significant extravasation of intravenous contrast medium (CIV) adjacent to the right side of both iliac branches. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 13 of 45
Fig. 8: Image immediately below of the previous one where it is displayed IVC located peripherally within the aneurysm sac(pink arrow) and a permeable inferior mesenteric artery (yellow arrow), findings in relation to type II endoleak. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 14 of 45
Fig. 9: 67 year old male patient with AAA treated with biiliac aortic stent. Abdominal aorta CT in a late phase shows contrast extravasation with peripheral location. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 15 of 45
Fig. 10: Sagittal MIP reconstruction of abdoimnal aorta CT in an arterial phase where there is a permeable lumbar artery and contrast extravasation into the aneurysm sac, findings regarding type II endoleak. Page 16 of 45
References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Treatment It is controversial. Some authors consider that this type of leak must maintain an indefinite follow up when the aneurysm does not increase in size. In fact, 40% of aneurysms thrombose. Others believe that they should be repaired because the collateral vessels can transmit blood pressure to the aneurysmal sac, which puts the patient at risk of a rupture. They can be treated with transarterial approach or by a direct translumbar puncture of the leak. Type III Endoleak It occurs when there is blood leakage through the prosthesis due to structural failure, which can be caused by a tear in the material or the presence of holes by a defective manufacture. A repeated stress on the prosthesis due to arterial pulsation can also cause this type of leak. Page 17 of 45
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Fig. 11: Type III endoleak: blood leakage through a defect in the prosthesis. References: Mustafa R. Bashir (2009) Endoleaks after endovascular abdominal aortic aneurysm repair: managment strategies according to CT findings. AJR:192 178-186 As well as I, type III endoleaks are considered a high pressure type with the high risk of rupture and measurable increase in the aneurysmal SAC. Findings CT scan of abdominal aorta: haemorrhagic or material collection of extravasated contrast located centrally within the aneurysmal SAC, distant from the anchor sites of the native vessel. Fig. 12: 64 year old male patient who went under emergency surgery for ruptured infrarenal AAA performing endovascular exclusion. Two weeks later he takes an abdominal aorta control where the no contrst phase showed an hemorragic collection into the aneurysm sac, of central location and adjacent to the left posterolateral region of the prosthesis, before the bifurcation. Findings regarding a type III endoleak. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 19 of 45
Fig. 13: Abdominal aorta CT in an arterial phase of the same where there is a significant IVC extravasation regarding type III endoleak. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 20 of 45
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Fig. 14: Sagittal reconstruction of the same patient where the IVC extravasation is displayed through the prosthesis in relation to type III endoleak. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Treatment It requires urgent handling. They can usually be corrected covering the defect with an extension of the prosthesis. It is believed that these endoleaks are the most dangerous because of the rapid growth of the aneurysmal sac. Endoleak type IV They are produced by porosity of the prosthesis. This type of leak is identified immediately after placement of the endoprosthesis with the patient being fully anticoagulated. It is an exclusion diagnosis. Page 22 of 45
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Fig. 15: Type IV endoleak: Prosthesis porosity with blood leaking therethrough. References: Mustafa R. Bashir (2009) Endoleaks after endovascular abdominal aortic aneurysm repair: managment strategies according to CT findings. AJR:192 178-186 Findings Post implantation angyography: Aneurysmal sac opacification without observing a clear source of the leak. Treatment They are self-limited, not requiring treatment and resolving spontaneously after removal of the anticoagulation. Endoleak type V It is produced by endotension. Although the exact cause is not known, the causes include a pre-existing leaking type I, II or III presented as radiologically hidden; ultrafiltration or a thrombus in the aneurysmal sac that produces an ineffective barrier to the transmission of pressure. Findings Abdominal aorta CT scan: continuous growth of the aneurysmal sac without clear radiological evidence of leakage. Page 24 of 45
Fig. 16: 65 year old male patient with an AAA excluded with a biiliac aortic stent. In the control study conducted in the year 2010 objective one infrarrerenal aneurysm sac with anteroposterior and transverse diameters of 6 cm. No evidence of IVC extravasations. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Fig. 17: Same patient as in the previous image. The control is performed annually, which demonstrates an increase of the aneurym's diameter, being in this study approximately 7 cm. No clear evidence of extravasation through IVC on the arterial phase or in the venous phase performed 90 seconds later, findings regarding endoleak type V. References: Radiodiagnóstico, Complejo Hospitalario Universitario de Orense Orense/ES Page 25 of 45
Treatment They are a short term low-risk injuries. However, the continuous growth of the aneurysmal sac usually requires surgical repair because there is a risk to a long-term rupture of the aneurysm. It is important to confirm the diagnosis with multiple imaging tests. Images for this section: Page 26 of 45
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Fig. 1: Type I endoleak: blood leakage from the prosthesis through one of the anchoring sites. Fig. 2: 67 year old male patient with AAA treated with a biiliac stent graft. The abdominal aorta CT without contrast do not displayed hemorrhagic collections Page 28 of 45
Fig. 3: Abdominal aorta CT (arterial phase) of the same patient. There is a contrast active leakage at the distal end of the aortic stent, findings regarding of a type Ia endoleak. Page 29 of 45
Fig. 4: Coronal reconstruction shows the contrast leakage into the aneurysm sac at the proximal level of the stent. Page 30 of 45
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Fig. 5: Blood reflux into the aneurysm sac through collateral vessels, being the most frequent the lumbar or inferior mesenteric artery. Fig. 6: 77 year old male patient with AAA and an aortobiiliac stent. Abdominal aorta CT without contrast shows no hemorrhagic collections. Page 32 of 45
Fig. 7: Arterial phase abdominal aorta CT in the same patient where there is a significant extravasation of intravenous contrast medium (CIV) adjacent to the right side of both iliac branches. Page 33 of 45
Fig. 8: Image immediately below of the previous one where it is displayed IVC located peripherally within the aneurysm sac(pink arrow) and a permeable inferior mesenteric artery (yellow arrow), findings in relation to type II endoleak. Page 34 of 45
Fig. 9: 67 year old male patient with AAA treated with biiliac aortic stent. Abdominal aorta CT in a late phase shows contrast extravasation with peripheral location. Page 35 of 45
Fig. 10: Sagittal MIP reconstruction of abdoimnal aorta CT in an arterial phase where there is a permeable lumbar artery and contrast extravasation into the aneurysm sac, findings regarding type II endoleak. Page 36 of 45
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Fig. 11: Type III endoleak: blood leakage through a defect in the prosthesis. Fig. 12: 64 year old male patient who went under emergency surgery for ruptured infrarenal AAA performing endovascular exclusion. Two weeks later he takes an abdominal aorta control where the no contrst phase showed an hemorragic collection into the aneurysm sac, of central location and adjacent to the left posterolateral region of the prosthesis, before the bifurcation. Findings regarding a type III endoleak. Page 39 of 45
Fig. 13: Abdominal aorta CT in an arterial phase of the same where there is a significant IVC extravasation regarding type III endoleak. Page 40 of 45
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Fig. 14: Sagittal reconstruction of the same patient where the IVC extravasation is displayed through the prosthesis in relation to type III endoleak. Page 42 of 45
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Fig. 15: Type IV endoleak: Prosthesis porosity with blood leaking therethrough. Fig. 16: 65 year old male patient with an AAA excluded with a biiliac aortic stent. In the control study conducted in the year 2010 objective one infrarrerenal aneurysm sac with anteroposterior and transverse diameters of 6 cm. No evidence of IVC extravasations. Fig. 17: Same patient as in the previous image. The control is performed annually, which demonstrates an increase of the aneurym's diameter, being in this study approximately 7 cm. No clear evidence of extravasation through IVC on the arterial phase or in the venous phase performed 90 seconds later, findings regarding endoleak type V. Page 44 of 45
Conclusion Endoleaks are one of the most frequent complications of endovascular repair of abdominal aortic aneurysm, which can lead to rupture of the aneurysmal sac or its growth if they are not repaired. The role of the radiologist in the presence of endoleaks consists in its proper diagnosis, characterization and classification, since it depends on the correct management both urgently as conservative. References 1. Mustafa R. Bashir. Endoleaks after endovascular abdominal aortic aneurysm repair: management strategies according to CT findings. AJR 2009; 192:W178-W186 2. Stavropoulos SW, Charagundla SR. Imaging techniques for detection and management of endoleaks after endovascular aortic aneurysm repair. Radiology 2007; 243:641-655 3. Gorich J, Rilinger N, Sokiranski R, et al. Leakages after endovascular repair of aortic aneurysms: classification based on findings at CT, angiography, and radiography. Radiology 1999; 213:767-772 Personal Information Page 45 of 45