Case 35 - TEVAR

Question 1

What is the differnece between TEVAR and open repair?

Answer 1

TEVAR

• minimially invasive - go through vascular access site
• avoid large incision –> less pain
• less hemodynamic fluid shifts
  
  • less blood loss
• less risk of hemodynamic instability perioperatively (no clamp, etc…)

Question 2

Anatomic requirements for EVAR?

Answer 2

• proximal neck (proximal landing zone) must be > 15 mm in length
• aneurysm neck diameter should not be larger than largest endograft available
• distal attach site must be nonaneurysmal and sufficent length to accomodate graft
• no important side branches (renal artery, IMA) should be involved
• one large straight iliac artery (to serve as a conduit for delivery of endograft system)
• no excessive aortic neck tortuosity or severe calcification

Question 3

What are surgical complications of EVARs?

Answer 3

• Insertion of endovascular delivery system precluded
  
  • iliac artery anatomy/pathology
  • aortic artery anatomy/pathology
• artery rupture with hypotension
• embolization of aortic material
  
  • bowel, lower extrem, brain, other organs
• guide wire trauma
  
  • aortic valve
  • myocardial perf with card tamp
• graft malposition
  
  • renal artery occlusion –> AKI
  • occluded intercostal or anterior spinal artery (artery of Adamkowitz) –> PARALYSIS

Question 4

Difference in outcomes between EVAR and open repair?

Answer 4

EVAR - assoc with lower incidence:

• early death
• paraplegia
• renal insuffiency
• tranfusion
• length of stay compared to pen

Long term outocme

• greater post-op surveillance required after EVAR
• greater secondary intervention with EVAR
• surival differences are the same after 2 years

Question 5

What are anesthetic options for EVAR patients?

Answer 5

• Local Anes
  
  • percutaneous catheter placement with limited incisions
• Regional (epid, continuous spinal)
  
  • extensive inguinal exploration
  • dissection or construction of fem-fem conduit
• general anes
  
  • surgical dissection retroperitoeum

Question 6

What are potential complications of proximal graft deployment?

Answer 6

• main complications = 1) distal migration with occlusion of major aortic branches, 2) inadequate exclusion of aneurysmal sac with resultant endoleak

Distal Migration

• occurs due to inadequate secure attachment to native aortic vessel wall
• Aortic blood flow pushes graft distally
  
  • induced hypotension during graft placement can prevent distal migration
  • Admin Adenosine –> temporarly stops heart and prevents forward flow during graft deployment

Question 7

what are the advantages of TEE during EVAR repair?

Answer 7

• aside from TEE able to assess cardiac function, TEE can assist with endograft placement
• assess distal aortic arch, descending thoracic aorta, prox abdominal aorta
• endograft leakage (doppler color flow)
• iatrogenic dissections
• endograft sizing and endograft location
• after graft placement –> TEE can assess for exclusion of flow into aneurysm sac - Endoleak.

Question 8

Is spinal cord ischemia a risk during EVAR?

Answer 8

Yes!

• SCPP = MAP - CSF (or venous pressure)
• reported incidence of spinal cord ischemia same between open vs EVAR
• descending aortic reconstruction can result in intercostal arteries being sacrificed (intercostal artery supply anterior spinal cord)
• RF for paraplegia = previous AAA repair, length of thoracic endograft
• pre-op lumbar drains and induced HTN should be considered during EVAR

Question 9

What is post-implantation syndrome?

Answer 9

• fever, elevated CRP, leukocytosis in abscence of infectious agent
• responds to NSAIDs
• EAR can induce an inflammatory response from endothelial cell activation 2/2 endograft device manipulation within the aneurysm
  
  • may lead to resp failure, ARDS, DIC, distributive shock
• thrombus of excluded aneurysm sac (s/p endograft) can initiate fibrinolysis (DIC)