In this episode Dr Yogi Sivakumaran and Dr Sam Farah discuss how they prepare, plan and perform an endovascular aneurysm repair (EVAR).
General Principles
- Quality of the CT Scan
- 1mm slices
- If initial scan – scan thoracic, abdomen and lower limbs; allows for exclusion of aneurysmal disease elsewhere as well as if baseline status of the aortia prior to intervention
- Also allows planning if a fenestrated repair required
- Centerline – images are not cross-sectional and end up with cross-sectional diameters
- Narrow diameter of the elliptical cross-section more in keeping with the true diameter
- Draw a diagram and compare with the rep and consultant’s plan – appreciation of the complexity of the case
- Date of the index scan
- Documentation calcification, dissection, thrombus and stenotic disease
- Site of the lowest renal artery
- Clock face of the renal arteries origin as well as the origin of the internal iliac arteries
- Angulation of the aortic neck
- Type of neck
- Straight, angulated (plan according to IFU), tapered (oversize on the basis of the diameter below the renal arteries), reverse tapered (careful to avoid oversizing), bulge and short
- Access vessels
- Diameters and lengths (which will be discussed)
- Grafts chosen
- Talk to the reps re: planning books
Pre-operative consideration
- In the era of an endovascular repair, a durable repair is desired
- Patient’s age
- Patient’s co-morbidities
- Renal function, cardiac and respiratory history
- Life expectancy
- Fitness for GA vs. LA and Sedation
- The patient better of with an open or endovascular management strategy
- Suitability for endovascular
- Complex vs. Standard EVAR
Imaging
Renal artery position
- Lowest renal artery; accessory renal arteries
Diameters
- Infrarenal aortic neck diameter (assess for infrarenal thrombus; aim < 25% of the circumference and <2mm thickness) – multiple across the length of the neck
- Aneurysm sac diameter
- Aortic bifurcation diameter
- CIA proximal, mid and distal
Lengths
- Aortic neck length
- Length from lowest renal to aortic bifurcation (to ensure sure that there is enough length for the contralateral limb)
- Length from aortic bifurcation to iliac bifurcation
Angles
- Renal arteries origin off the aortic
- Internal iliac arteries origin off the bifurcation
- Supra and infrarenal angulation if appropriate
Access vessels
- Femoral/Iliac artery diameter
- Tortuosity of the iliac arteries
Large lumbar vessels or inferior mesenteric artery >3mm