Population Covered By The Guidance
This pathway provides guidance for imaging follow-up of adult patients following endovascular abdominal aortic aneurysm repair (EVAR).
Lead Researcher: Dr Sian Chin
Experts & Contributors: Dr Ravinder Dhillon, Dr Philip Misur, Prof Paul Norman, Dr Greg van Schie
Date reviewed: May 2018
Date Published: June 2018
- Endoleaks occur in 15-25% of patients within the first 30 days of EVAR and are often asymptomatic 1
- Type II endoleaks are the most common and often spontaneously occlude. 2 Type I and III endoleaks are associated with an increased risk of rupture 3 and are usually managed promptly 4
- An early one-month postoperative study is done to assess adequacy of AAA exclusion, baseline endograft positioning and AAA size. If no endoleak is detected, subsequent studies may be performed annually 5
- Delayed endoleaks may occur months or years after EVAR so lifetime surveillance is recommended. 5 The incidence of delayed complications requiring treatment is about 3% 6, 7
- Annual duplex ultrasound is most likely sufficient for routine surveillance in the absence of new endoleak or sac enlargement, and eliminates radiation exposure, reduces cost and avoids use of contrast 5
- CTA is used if sac is increasing or duplex suggests an endoleak 5
Date of literature search: March 2018
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Dias NV, Riva L, Ivancev K, Resch T, Sonesson B, Malina M. Is there a benefit of frequent CT follow-up after EVAR? Eur J Vasc Endovasc Surg. 2009;37(4):425-30. (Level III evidence). View the reference
- Liaw JV, Clark M, Gibbs R, Jenkins M, Cheshire N, Hamady M. Update: complications and management of infrarenal EVAR. Eur J Radiol. 2009;71(3):541-51. (Review article). View the reference
- Mehta M, Paty PS, Roddy SP, Taggert JB, Sternbach Y, Kreienberg PB, et al. Treatment options for delayed AAA rupture following endovascular repair. J Vasc Surg. 2011;53(1):14-20. (Level III evidence). View the reference
- Hallett RL, Ullery BW, Fleischmann D. Abdominal aortic aneurysms: pre- and post-procedural imaging. Abdominal radiology (New York). 2018 (Review). View the reference
- Chaikof EL, Dalman RL, Eskandari MK, Jackson BM, Lee WA, Mansour MA, et al. The society for vascular surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2. (Guideline). View the reference
- Hiramoto JS, Reilly LM, Schneider DB, Sivamurthy N, Rapp JH, Chuter TA. Long-term outcome and reintervention after endovascular abdominal aortic aneurysm repair using the Zenith stent graft. J Vasc Surg. 2007;45(3):461-5; discussion 5-6. (Level II evidence). View the reference
- Vallabhaneni SR, Harris PL. Lessons learnt from the EUROSTAR registry on endovascular repair of abdominal aortic aneurysm repair. Eur J Radiol. 2001;39(1):34-41. (Level II evidence). View the reference
- Back MR. Surveillance after endovascular abdominal aortic aneurysm repair. Perspect Vasc Surg Endovasc Ther. 2007;19(4):395-400; discussion 1-2. (Review article). View the reference
- Hiatt MD, Rubin GD. Surveillance for endoleaks: how to detect all of them. Semin Vasc Surg. 2004;17(4):268-78. (Review article). View the reference
- Chisci E, Setacci F, Iacoponi F, de Donato G, Cappelli A, Setacci C. Surveillance imaging modality does not affect detection rate of asymptomatic secondary interventions following EVAR. Eur J Vasc Endovasc Surg. 2012;43(3):276-81. (Level III evidence). View the reference
- Roos JE, Hellinger JC, Hallet R, Fleischmann D, Zarins CK, Rubin GD. Detection of endograft fractures with multidetector row computed tomography. J Vasc Surg. 2005;42(5):1002-6. (Level V evidence). View the reference
- Wolf YG, Johnson BL, Hill BB, Rubin GD, Fogarty TJ, Zarins CK. Duplex ultrasound scanning versus computed tomographic angiography for postoperative evaluation of endovascular abdominal aortic aneurysm repair. J Vasc Surg. 2000;32(6):1142-8. (Level III evidence). View the reference
- Sun Z. Diagnostic value of color duplex ultrasonography in the follow-up of endovascular repair of abdominal aortic aneurysm. J Vasc Interv Radiol. 2006;17(5):759-64. (Review article). View the reference
- Zaiem F, Almasri J, Tello M, Prokop LJ, Chaikof EL, Murad MH. A systematic review of surveillance after endovascular aortic repair. J Vasc Surg. 2018;67(1):320-31.e37. (Review article). View the reference
Pathway User Guide
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The relative radiation level (RRL) of each imaging investigation is displayed in the pop up box.
| SYMBOL | RRL | EFFECTIVE DOSE RANGE |
|---|---|---|
| None | 0 | |
| Minimal | < 1 millisieverts | |
| Low | 1-5 mSv | |
| Medium | 5-10 mSv | |
| High | >10 mSv |
Disclaimer
Status Of Recommendations Each pathway is designed to assist clinicians in situations when faced with a large array of possible diagnostic tests and examinations. However, it is recognised that diagnostic practice may differ from a particular pathway depending on local availability of equipment and expertise, as well as the experience of individual clinicians. Therefore each pathway is neither a rigid set of rules, nor a substitute for clinical assessment, and individual patient circumstances should always be considered.
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Computed Tomography Angiography (CTA)
CT Angiography
Considered the gold standard for EVAR assessment
- The 2-dimensional and 3-dimensional contrast-enhanced computed tomography imaging currently serves as the gold standard for serial endovascular aneurysm repair (EVAR) assessment. EVAR follow-up protocols usually include arterial and delayed phase contrast images as well as non-contrast images
- High spatial resolution allows precise measurement of anatomy, visualisation of endoleaks and assessment of device kink, fracture and migration
- Disadvantages include significant cumulative radiation exposure with lifetime surveillance and the use of iodinated contrast
- To reduce radiation exposure, CTA is only recommended at one-month and one-year follow-up, and if there is an abnormality detected on ultrasound thereafter
- Non-contrast imaging of the whole aorta is recommended every five years however CTA might be considered if there is no contraindication to contrast
Duplex Ultrasonography
Duplex Ultrasonography
Recommended with CTA for follow-up at 1-month and 1-year post EVAR
- High-quality duplex ultrasound can be used for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA
- In one systematic review, the unenhanced colour duplex scanning had a sensitivity of 66%, a specificity of 93%, a positive predictive value of 76%, and a negative predictive value of 90% compared with CTA. The sensitivity increased to 81% with contrast material-enhanced colour duplex US compared with unenhanced colour duplex US
- A recent meta-analysis found non-contrast enhanced ultrasound to have a lower endoleak detection rate than CTA, but concluded that missed findings are likely to be of lesser clinical significance
- There are no studies comparing the outcomes of different surveillance intervals
- Colour duplex ultrasound is suggested for annual surveillance, if neither endoleak nor AAA enlargement is observed 1-year after EVAR; CT imaging may be used if ultrasound is not possible
- If a type II endoleak is associated with an aneurysm sac that is shrinking or stable in size, 6-monthly colour duplex ultrasound surveillance is suggested for 24 months, then annually thereafter
- The accuracy is limited by
- obesity
- intestinal gas
- artery or AAA wall calcification; they can block ultrasound transmission
- operator skill
Duplex Ultrasonography
Duplex Ultrasonography
Sufficient for routine surveillance in the absence of a new endoleak to avoid radiation exposure
- High-quality duplex ultrasound can be used for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA
- In one systematic review, the unenhanced colour duplex scanning had a sensitivity of 66%, a specificity of 93%, a positive predictive value of 76%, and a negative predictive value of 90% compared with CTA. The sensitivity increased to 81% with contrast material-enhanced colour duplex US compared with unenhanced colour duplex US
- A recent meta-analysis found non-contrast enhanced ultrasound to have a lower endoleak detection rate than CTA, but concluded that missed findings are likely to be of lesser clinical significance
- There are no studies comparing the outcomes of different surveillance intervals
- Colour duplex ultrasound is suggested for annual surveillance, if neither endoleak nor AAA enlargement is observed 1-year after EVAR; CT imaging may be used if ultrasound is not possible
- If a type II endoleak is associated with an aneurysm sac that is shrinking or stable in size, 6-monthly colour duplex ultrasound surveillance is suggested for 24 months, then annually thereafter
- The accuracy is limited by
- obesity
- intestinal gas
- artery or AAA wall calcification; they can block ultrasound transmission
- operator skill
Computed Tomography (CT) or CTA
Computed Tomography (CT) or CTA
Imaging of the entire aorta is recommended every 5 years; consider CTA if no contraindication to contrast
Duplex Ultrasonography
Duplex Ultrasonography
Suggested for surveillance of a type II endoleak associated with an aneurysm sac that is shrinking or stable, at 6-month intervals for 24 months and then annually thereafter
- High-quality duplex ultrasound can be used for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA
- In one systematic review, the unenhanced colour duplex scanning had a sensitivity of 66%, a specificity of 93%, a positive predictive value of 76%, and a negative predictive value of 90% compared with CTA. The sensitivity increased to 81% with contrast material-enhanced colour duplex US compared with unenhanced colour duplex US
- A recent meta-analysis found non-contrast enhanced ultrasound to have a lower endoleak detection rate than CTA, but concluded that missed findings are likely to be of lesser clinical significance
- There are no studies comparing the outcomes of different surveillance intervals
- Colour duplex ultrasound is suggested for annual surveillance, if neither endoleak nor AAA enlargement is observed 1-year after EVAR; CT imaging may be used if ultrasound is not possible
- If a type II endoleak is associated with an aneurysm sac that is shrinking or stable in size, 6-monthly colour duplex ultrasound surveillance is suggested for 24 months, then annually thereafter
- The accuracy is limited by
- obesity
- intestinal gas
- artery or AAA wall calcification; they can block ultrasound transmission
- operator skill
