Contemporary imaging methods for the follow-up after endovascular abdominal aneurysm repair: a review.

Abstract

Abdominal aortic aneurysm (AAA) is defined as a localized enlargement of the aortic cross-section where the diameter is greater than 3 cm or more than 50% larger than the diameter in a normal segment. The most important complication of AAA is rupture, which, if untreated, results in mortality rates of up to 90%. Conventional open surgical repair is associated with significant 30-day mortality. Endovascular aneurysm repair (EVAR) is a significantly less invasive procedure; it is related to a lower early mortality rate and a lower number of perioperative complications. Although EVAR is a minimally invasive technique, lifelong follow-up imaging is necessary due to possible late complications including endoleak, recurrent aneurysm formation, graft infection, migration, kinking and thrombosis. The total rate of complications after EVAR is estimated at approximately 30%, and the rate of complications that require intervention is 2–3%. Early detection and progression analysis of such situations is crucial for proper intervention.

Contemporary follow-up imaging after endovascular repair of lower extremity atherosclerotic lesions

“…DSA is still called the “gold standard” of vessel imaging methods according to TASC II [6]. However, the main drawback of this technique is its invasiveness related to the vessel puncture, the possibility of arterial dissection or distal embolisation due to atheromatous plaque fragmentation, the significant radiation dose, and the intra-arterial contrast medium application, which, especially in atherosclerotic patients, may lead to contrast-induced nephropathy [20,28]. Moreover, similarly to plain radiograph, invasive angiography can only project three-dimensional plaque to a two-dimensional image.…”

“…CTA is the current reference standard for the follow-up after PTA. The modality is widely available, less operator-dependent than US, and can be performed rapidly in unstable patients [20]. Because contemporary CT units offer a very good spatial resolution, CTA enables a precise measurement of arterial diameters, detection of re-stenosis, as well as detection local PTA complications.…”

“…These techniques use multiple advanced mathematical operations to optimise the image by reducing the noise. Iterative reconstructions are widely available in contemporary CT scanners and should be used as a routine [20]. Model-based reconstructions are still a work in progress because the technology is expensive and time-consuming, but they allow a dose reduction of as much as 73% as compared with low-dose conventional adaptive iterative reconstruction while maintaining diagnostic accuracy [36].…”

“…Nitinol stents are most suitable for magnetic resonance angiography (MRA) surveillance because Nitinol does not produce susceptibility artefacts that completely prohibit vessel assessment. Conversely nickel-alloy and stainless-steel components should not be examined using MRA [20].…”

“…Although DSA is still considered the gold standard for arterial imaging [6], it is obvious that the invasiveness and the cost of the procedure strongly limit its application for follow-up after endovascular treatment [20]. In recent guidelines by the American College of Cardiology and American Heart Association, the strongest evidence (class of recommendation I/level of evidence C-EO) for longitudinal follow-up of patients with PAD, who have undergone lower extremity revascularisation, was given to clinical evaluation and ankle/brachial index (ABI) measurement [57].…”