Biomedical Engineering Reference
In-Depth Information
Fig. 3
Endovascular aneurysm repair (EVAR), stent-graft deployment sequence
Tabl e 1
Complications
involving stent-grafts
(Adapted from [
3
])
Early complications
Late complications
Graft kink
Graft migration
Endoleaks
Neck dilatation
Graft explantation
Endoleaks
Structural failure
Structural failure: component separation,
fabric tears, hook fractures
Graft infection
complications can be classified as early or late and further detailed as systemic or
related with the delivery, deployment, or the device itself [
3
]. Table
1
presents some
of EVAR's problems involving stent-grafts.
The current surveillance protocol involves imaging exams, namely ultrasound
and computed tomography angiography (CTA), at 1, 6, and 12 months after the
procedure, and thereafter, on an annual basis [
9
].
Device migration and stent fractures or other indication of device fatigue are
clear in plain abdominal radiography. Ultrasonography, besides allowing measuring
the aneurysm sac, is effective in the detection of endoleaks but, even with enhanced
sensitivity obtained with the use of contrast agents, requires a skilled technician to
interpret the exams. CTA, MRI (magnetic resonance imaging) and MRA (magnetic
resonance angiography) are sensitive tools to detect endoleaks but cannot be
repeated often due to radiation and/or the use of nephrotoxic contrast agents.
Furthermore, these exams are considered time consuming and expensive.
