AAA : Procedural Management

Evaluation for endoluminal AAA repair

· Spiral CT with contrast ± 3D reconstruction

— Confirm:

Size

Diameter, shape & character of neck

Diameter & tortuosity of iliacs

— If OK ® calibrated aortogram

· Aortogram

— Neck

³ 20 mm long from renal arteries

< 30 mm diameter

<30° angulation

°thrombus / irregular calcification in neck

° flared

— Iliacs

³ 7mm to accommodate graft

Tortuosity / calcification make deployment difficult



AAA

(Ruptured)

· Cell saver, anasethetic management of blood turnover and replacement agents, infusion lines and monitoring as appropriate

Forced air warming devices to preserve temparture and thus coagulation.
Transperitoneal midline access
Supine, both arms abducted

· (Shave), Prep, drape - exposing both groins (± set up retractor) prior to induction

— (Depends on clinical state of pt)

· Midline incision xiphi - pubis

· ± control supra coeliac aorta with direct pressure of aorta against L spine

· Incise posterior peritoneum lateral to D-J flexure

· Mobilise D-J & SB mesentery on AAA to (R)

· Blunt dissection to define neck

· Initial digital control of neck

· Assess for & place proximal clamp

— Can use intraaortic ballon control initially

· For supra coeliac control

— Incise gastrocolic omentum

— Incise R crus

— Blunt dissection of aorta laterally L & R

— Place straight clamp

· Once proximal control gained:

— Place retractors

— Expose & clamp iliacs (identify v & ureter)

— Resuscitate

· Identify IMA

— Assess patency

— Ligate & transect if patent & no compromise to colon

— Or if compromise on assesment excise button of AAA with IMA

· Open AAA

· Evacuate contents

· Control bleeding lumbars

· Prosthetic graft replacement; tubed or bifurcated as necessary.

— Dacron / PTFE

· Proximal anastomosis with 3-0 prolene

· Clamp graft

· Assess proximal suture line by release of proximal clamp

· Reapply proximal clamp distal to anastomosis

· Irrigate & suction graft

· Stretch & cut to length

· Distal anastomosis(es) with 3-0 prolene

· Flush aorta from above & below prior to completion of anastomoses

— If ° back bleeding ® thrombectomy of iliacs

· Slowly release clamp

· Assess iliac & femoral pulses

· Reimplant IMA if necessary using Satinsky

· Confirm haemostasis

· Close aneurysm sac over graft

· Appose peritoneum


Notes:


1. Depending on length of neck, may need to mobilise the left renal vein.
After division of ligament of Treitz, expose and mobilize the left renal vein.
- ligate left adrenal, gonadal and renal-lumbar veins to expose the left renal artery and suprarenal aorta.

2. Proximal Control

 Supraceliac clamping
- if ruptured AAA, juxtarenal disease, infected graft / tissue, neck heavily involved with atheroma.
Note the following technically important steps:
- incision must high; be well onto xiphoid; maybe even splitting lower sternum if costal arch in the way
- Must take down the triangular ligament of the left lobe of liver.
- adequately retract underside of diaphragm on either side; folding hepatic lobe onto itself, padding to right of midline.
- NG tube; aids in dissecting off the oesophagus
- gentle traction on stomach and GE junction then divide gastrohepatic ligament (lesser omentum)
- beware replaced left hepatic artery that may travel beneath here (pre-op imaging should have been examined).
- Dissect out the aorta, attached to crus and oesophagus.
- surround it with vessel tape

3. Difficulty?
Use a swab-stick to compress aorta against the spine while progressing control
Dangerous blind clamping can injure iliac, renal, mesenteric veins ureters and bowel

4. Hypotension on unclamping?
Gentle intermittent digital pressure; controlled slow release
Allows anaesthetic buffering of haemodynamic status.