Quiz 8

Question 1

Eligibility as determined by imaging:

Answer 1

Proximal aneurysm neck

• Length > 15mm
• Diameter < 30mm
• Angulation < 60 degrees (in long axis)
• Thrombus < 2mm layer of mural thrombus
• Distal Landing Zone :adequate diameter and length
• Iliac arteries: Absence of aneurysm and occlusive disease
• Access Arteries: adequate diameter and absence of occlusive disease

Question 2

Local Anesthesia with MAC

Answer 2

• Should not decrease peri-operative monitoring
• Patient must be able to lay supine for 1-2 hours
• Must be accepted by patients- deep sedation will not be possible as they will need to hold their breath occasionally for imaging
• Favorable anatomy making retroperitoneal incision unnecessary
• Favorable aneurysm anatomy making the use of fenestrations or branched grafts unlikely, thus a shorter operative time.

Question 3

Central Neuraxial Blockade

Answer 3

• Both spinal and lumbar epidural have been used safely for EVAR’s.
• Patients should have no contraindications to central neuraxial blockade
• No need for TEE
• No need for MEP or SSEP’s
• No need for measures to achieve a motionless field during stent deployment

Question 4

General Anesthesia

Answer 4

• Good choice for a complicated EVAR (especially if planned fenestrated or branched endografts)
• Need for iliac access
• Planned use of TEE
• Planned hemodynamic manipulations to create a motionless field
• Planned SSEP and /or MEP monitoring
• History of difficult airway

Question 5

anesthetic Goals:

Answer 5

• Maintain hemodynamic stability
• Avoid hypertension and tachycardia
  - Decrease ischemic coronary events
  - Reduce dP/dT in respect to aorta
• Maintenance of intravascular volume and early identification / management of bleeding

Question 6

PRE-OP CONSIDERATIONS

Answer 6

• EVAR should still be considered high-risk surgery

- Patients should undergo functional testing consistent with ACC/AHA guidelines.

Question 7

Acute kidney injury (AKI) – may occur post-op due to:

Answer 7

• Hypoperfusion
• Mechanical encroachment of stent graft on renal vessels
• Emboli to the renal arteries
• Contrast induced nephropathy (occurs in 2-10% of patients)

Question 8

Renal Considerations

Answer 8

• Ensure perioperative euvolemia
• Maintain cardiac output and blood pressure
• Limit contrast dye exposure
• Use iso-osmolar non-ionic contrast dye
• Pharmacologic strategies in patients with baseline kidney disease
  - N-Acetylcysteine (Mucomyst)
  - Sodium Bicarbonate
  - Statin Drugs

Question 9

Iatrogenic Hypotension

Answer 9

• Intra-arterial injection of nitroglycerin into major aortic branches (tx vasospasm)
• Maneuvers to temporarily interrupt blood flow and create a motionless field during device deployment
  - IV adenosine
  - Rapid ventricular pacing 180 bpm induced so no output
  - Right atrial inflow occlusion

Question 10

CSF drainage

Answer 10

an attempt to increase spinal cord perfusion pressure

• SCPP = MAP (distal) – CSF pressure
• Efficacy of CSF drainage has been proven in open thoracic aneurysm repairs
• Multiple case reports on reversal of paraplegia with placement of CSF drain.
• Complications include meningitis, epidural abscess, persistent CSF leak and intracranial hypotension leading to herniation!!

Question 11

Blood supply of the spinal cord

Answer 11

• Posterior – 2 arteries originating form the PICA or vertebral artery
• Anterior Spinal Artery
  - Caudal contribution – Internal iliac and its branches
  - Thoracic contribution – radicular branches of the intercostal arteries
  - Largest is the Artery of Adamkiewicz (arteria radicularis magna)
  - Arises from the aorta at T9 – T12 but can arise anywhere from T5 to L5.*
  - Exclusion of this artery can result in paraplegia

Question 12

causes of SPINAL CORD ISCHEMIA

Answer 12

• Exclusion of the Artery of Adamkiewicz
• Exclusion of critical intercostal arteries
• Previous abdominal aortic aneurysm repair
  - May have already compromised collateral vascular supply to the spinal cord (ie: prior sacrifice of the IMA or median sacral artery)
• Injury to the external iliac artery – feeder of spinal cord collaterals.
• Hypotension associated with occult retroperitoneal bleed
• Severe atherosclerosis of the thoracic aorta – increased risk of emboli.

Question 13

Management of Paraplegia Following TEVAR

Answer 13

• Elevation of MAP (>80 mmHg)
  - Improves spinal cord perfussion pressure
  - Counteracts neurogenic shock caused by autonomic dysfunction
• Therapeutic CSF drainage
• Repeated neurologic examination for evidence of reversal of paraplegia
• Avoid abrupt cessation of CSF drainage

Question 14

Endoleaks:

Answer 14

Type I – involves the proximal or distal seal zone. May require further ballooning or placement of another graft.

Type II – Due to retrograde flow from the intercostals

Type III – Occurs with inadequate overlap and seal between modular components

Type IV – Occurs due to porosity of graft (rare in modern grafts)

Type V – Endotension – continued sac extension with no identifiable source

Question 15

look at slide 49

Answer 15

.

Question 16

Indications for CSF drain

Answer 16

• involvement T9-T12 (artery of Adamkiewicz)
• Involvement of arch vessels (origin ant. spinal a.)
• Previous TAA if AAA repair or vice versa
• Symptomatic spinal ischemia