- Endovascular aneurysm repair
EVAR which stands for Endovascular Aneurysm Repair (or Endovascular Aortic Repair), is a type of
Endovascular surgery used to treat anabdominal aortic aneurysm or AAA.Patient screening
Before patients are deemed to be a suitable candidate for this treatment, they have to go through a rigorous set of tests. These include a CT scan of the aorta and blood tests. The CT scan gives precise measurements of the aneurysm and the surrounding anatomy. In particular the calibre/tortuosity of the iliac arteries and the relationship of the neck of the aneurysm to the renal arteries are important determinants of whether the aneurysm is amenable to endoluminal repair.
The procedure
The procedure is carried out in a sterile environment, usually a theatre, under x-ray fluoroscopic guidance. It is carried out by a vascular surgeon or an Interventional Radiologist who collaborate on most cases. The patient is either given a full GA (general anaestheic) or an epidural.
Vascular 'sheaths' are introduced into the patient's femoral arteries, through which the guidewires, catheters and eventually, the
Stent Graft is passed.Diagnostic angiography images or 'runs' are captured of the aorta to determine the location on the patient's renal arteries, so the stent can be deployed below these. The main 'body' of the stent graft is placed first, with the 'limbs' which join on to the main body and sit in the
iliac s, placed later.The idea is that the covered stent, once in place acts as a false lumen for blood to travel down, and not into the surrounding aneurysm sac. This therefore immediately takes the pressure off the aneurysm, which itself will thrombose in time.cite journal |author=Greenhalgh RM, Powell JT |title=Endovascular repair of abdominal aortic aneurysm |journal=N. Engl. J. Med. |volume=358 |issue=5 |pages=494–501 |year=2008 |pmid=18234753 |doi=10.1056/NEJMct0707524 |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=18234753&promo=ONFLNS19]
Complications
ystemic
Myocardial infarction, congestive heart failure, arrhythmias, respiratory failure,
renal failure Procedure related
Dissection, malpositioning, renal failure, thromboembolizaton,
ischemic colitis , groinhematoma , wound infectionDevice related
Migration, detachment, rupture, stenosis, kinking
Endoleaks
An endoleak is a leak into the aneurysm sac after endovascular repair. Four types of endoleaks exist:
*Type I - Perigraft leakage atproximal ordistal graft attachment sites (near the renal and iliac arteries)
*Type II - Retrograde flow from collateral branches such as the lumbar, testicular and inferior mesenteric arteries
*Type III - Leakage between different parts of the stent (at the anastomosis between components)
*Type IV - Leakage through the graft wallFootnotes
External links
* [http://www.evartrials.org/index.htm The EVAR Trial: Data and Information]
* [http://www.vascularweb.org/_CONTRIBUTION_PAGES/Patient_Information/NorthPoint/Endovascular_Stent_Graft.html Information for patients]
* [http://www.stent-graft.com Information for patients and medical professionals]
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