Pathway
Pathway Diagram
Images
Image Gallery
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Teaching Points
Teaching Points
- An initial early (less than 1-2 months) postoperative study is done to assess adequacy of AAA exclusion, baseline endograft positioning, AAA size. Subsequent studies to be performed at a 6-month interval.
- The majority of follow up is done with ultrasound to avoid CT radiation and contrast.
- CT is used if sac is increasing or duplex suggests an endoleak.
ct
Computed Tomography (CT)
- The 2-dimensional and 3-dimensional contrast-enhanced computed tomography imaging currently serves as the gold standard for serial endovascular aneurysm repair (EVAR) assessment 1,2,3
- It allows visualization of both the morphology of the aneurysm, including the presence of associated thrombus or calcification, and structural components of the endovascular device
- 3-phase contrast-enhanced CT imaging can diagnose the majority of EVAR complications with the possible exception of reliable detection of progressive iliofemoral occlusive disease that may threaten endograft limb patency. Duplex ultrasound can provide the best testing for anatomical and haemodynamic assessment of the stenosis 1
- Most centers use a surveillance protocol incorporating an initial early (<1-2 months) postoperative study to assess adequacy of AAA exclusion, baseline endograft positioning, AAA size 1,4
- Subsequent studies to be performed at a 6-month interval. 5 If regression of AAA sac diameter by 5 mm or more or to a size less than 5 cm occurs, then intervals are lengthened to annual testing. Imaging intervals are extended
to every 2 to 3 years if further sac regression to less than 4 cm diameter occurs 1
us
Duplex Ultrasonography
- High-quality duplex ultrasound can be used for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA 6
- 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 7
- The accuracy is limited by 1
- obesity
- intestinal gas
- artery or AAA wall calcification; they can block ultrasound transmission
References
References
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Back MR. Surveillance after endovascular abdominal aortic aneurysm repair. Perspect Vasc Surg Endovasc Ther. 2007;19(4):395-400. (Review article)
- Balm R, Jacobs MJ. Use of spiral computed tomographic angiography: in monitoring abdominal aortic aneurysms after transfemoral endovascular repair. Tex Heart Inst J. 1997;24(3):200-3. (Level V evidence)
- Hiatt MD and Rubin GD. Surveillance for endoleaks: how to detect all of them. Sem Vasc Surg. 2004;17(4):268-278. (Review article)
- Sternbergh WC, Greenberg R, Chuter T, Tonnessen B. Redefining postoperative surveillance after endovascular aneurysm repair: recommendations based on 5-year follow-up in the US Zenith multicenter trial. J Vasc Surg. 2008;48(2):278-84. (Level II evidence)
- Hirsch AT, et al. ACC/AHA guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic). 2005. (Practice Guidelines). 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)
- 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. (Level II evidence)
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