Another relative contraindications include prohibitively small iliac arteries, aneurysmal iliac arteries, prohibitively small femoral arteries, or circumferential calcification of the femoral or iliac arteries.In addition to a short proximal aortic neck, the neck may be angulated, large in diameter, or shaped like a funnel (conical) where the neck diameter at the top is larger than the neck diameter at the bottom. Along with a short proximal aortic neck, necks with any of these characteristics are called "hostile necks" and endovascular repair can be either contraindicated or associated with early-late complications of endoleak, or endograft migration, or both.Many of the advances in EVAR technique aim to adapt EVAR for these situations, and advanced techniques allow EVAR to be employed in patients who previously were not candidates. Technique
The procedure is carried out in a sterile environment under fluoroscopic guidance. It is usually carried out by a vascular surgeon, interventional radiologist or cardiac surgeon, and occasionally, general surgeon or interventional cardiologist. The procedure can be performed under general, regional (spinal or epidural) or even local anesthesia. Access to the patients femoral arteries can be with surgical incisions or percutaneously in the groin on both sides. Vascular sheaths are introduced into the patients femoral arteries, through which guidewires, catheters, and the endograft are passed.Diagnostic angiography images are captured of the aorta to determine the location of the patients renal arteries, so the stent-graft can be deployed without blocking these. Failure to achieve this will cause kidney failure.
Type III - Leakage between overlapping parts of the stent (i.e., the connection between overlapping components) or rupture through graft material. Type IV - Leakage through the graft wall due to the quality (porosity) of the graft material. As seen in first-generation grafts, changes in graft material in modern devices have decreased the prevalence of type IV leaks. Type V - Expansion of the aneurysm sac without an identifiable leak. Also called "endotension".Type I and III leaks are considered high-pressure leaks and are more concerning than other leak types. Depending on the aortic anatomy, they may require further intervention to treat. Type 2 leaks are common and often can be left untreated unless the aneurysm sac continues to expand after EVAR. Spinal cord injury
Spinal cord injury is a devastating complication after aortic surgery, specifically for thoracoabdominal aortic aneurysm repair; severe injury could lead to urine and fecal incontinence, paresthesia and even paraplegia. The risk varies between studies with two metanalysis demonstrating a pooled incidence of spinal cord injury 2.2% and 11%. Predictive factors include increasing extent of coverage, hypogastric artery occlusion, prior aortic repair and perioperative hypotension. Spinal cord injury related to aortic repair occurs due to impaired blood flow to the spine after coverage of blood vessels, important to the blood circulation of the spine, namely intercostal- and lumbar arteries. A few methods exist for potentially reversing spinal cord injury, if it arises, elevated blood pressure, increased oxygenation, blood transfusion and cerebrospinal fluid drainage.