- Endovascular repair is an accepted treatment for complicated Type B aortic dissection, with the goals of covering the primary entry tear, expanding the compressed true lumen, inducing false lumen thrombosis, and preventing aneurysm development or rupture. - Key procedural considerations include defining the indication clearly, reviewing imaging to locate the primary tear, choosing the best access vessel, using techniques like blood pressure manipulation to aid deployment, and being familiar with the capabilities and limitations of the endografts used. - There is still uncertainty around the optimal use of bare dissection stents and when TEVAR is appropriate for uncomplicated dissection. Ongoing research through randomized trials may provide answers.

1. Endovascular Repair of Acute
Aortic Dissection
Kent MacKenzie, MD
Division of Vascular Surgery
McGill University
Montreal, Quebec

2. Disclosures
• Medtronic consultancy agreement
• Speaking fees from Cook

3. Acknowledgements
• OK Steinmetz, MM Corriveau, CZ Abraham,
D Obrand
• J Titley MD, Hamilton, Ontario

4. Acute Aortic Dissection
What is it?

7. Basic Epidemiology of Dissection
• 4:1 male to female
• 60-75% are Stanford Type A
– Peak between 50-60 years
• 25% are Stanford Type B
– Peak between 60-70 years
• Hypertension in >70%

8. Basic Epidemiology of Dissection
• Other factors:
– Cystic Medial Necrosis (Marfan’s, E-D synd)
– Pregnancy
– Cocaine
– Bicuspid valve
– Aortic coarctation
– Syndromes - Turner’s, Noonan’s, etc
– Chronobiologic patterns
• Early am
• Winter vs. Summer

9. Clinical Findings in Dissection
• Pain
• Hypertension
• Neurologic
– Syncope
– Stroke
– Spinal cord ischemia
• Limb ischemia

10. Complications of Dissection
• Type A
– Death from coronary malperfusion,
tamponade, rupture
– Stroke and distal malperfusion
• Type B
– Rupture
– Malperfusion - visceral, spinal, extremity
– Aneurysm

11. Intervention
• Complicated or Failure of Medical Therapy
• What is Complicated? (Failure of Medical)
– Rupture
– Aneurysmal false lumen or expansion
– Malperfusion
– Persistent pain
– Untreatable hypertension

12. Open Repair

15. Open Repair
• Advocated by some for all cases of
complicated Type B dissection requiring
intervention
• Role of open repair in the Endo era is
further blurred

16. Endovascular Repair
• Currently accepted as a viable treatment
option in selected cases of complicated
Type B aortic dissection
• What is Complicated? (Failure of Medical)
– Rupture
– Aneurysmal false lumen or expansion
– Malperfusion
– Persistent pain
– Untreatable hypertension

17. Endovascular Repair
• Where did the generalized allure for TEVAR
for Aortic Dissection start?

19. Endovascular Repair
• Case reports
• Case series
• Cohort studies
• Single-center and multi-center Registries

20. Endovascular Repair

21. Endovascular Repair
• At RVH:
–Approx 170 TEVAR
–23% indication is either:
• Acute complicated type B dissection
• IMH with ulcer

22. Endovascular Repair
• Goals
– Cover entry tear of the dissection
– Expansion of compressed true lumen
– Induce false lumen thrombosis
– Allow remodeling of aorta
– Potentially prevent aneurysm development
– Without the morbidity of open repair

23. Endovascular Repair
• Concept of inducing true lumen expansion
and false lumen thrombosis is a valid one:
– Reduces morbidity/mortality of malperfusion
– Lowering the risk of false lumen enlargement
• aneurysm

28. Endovascular Repair
• In the real world:
• True lumen expansion and false lumen
thrombosis in complicated Type B dissection
can be achieved

29. Pain, expansion, HPTN 2008

35. Procedural issues to be considered
• Define your indication
• Review the CT images
• ‘Best guess’ for location of primary tear
• Determine appropriate vessel diameters
– Guiding graft selection

36. Procedural issues to be considered
• Deployment Access Vessel
– Best femoral/iliac for delivery
– Assure true lumen graft deployment
• Femoral access with true lumen imaging
• Brachial access
• TEE confirmation

37. Procedural issues to be considered
• Imaging
– Quality
– Flush catheter access and position
– Contrast delivery
– Image Intensifier angulation

38. Imaging - Angulation

39. 45
LAO
o

40. 45
LAO
o

41. Imaging Quality C-arm

42. Imaging Quality Angiosuite

43. Imaging Quality Angiosuite

44. What procedural issues should be
considered?
• Blood pressure manipulation during
deployment
– Low - nitro, beta blockers
– Very low - adenosine, rapid RV pacing

45. Rapid RV pacing
Nienaber C et al. J Endovasc Ther 2007.

46. What procedural issues should be
considered?
• Graft oversizing (? less)
• ? Limited use of ballooning
• Stent graft specific deployment steps
–Understand your grafts
• Strengths and Weaknesses

47. Graft Selection

48. Graft Selection

49. Have to be familiar with the grafts you will use
– What they are capable of doing
– How they will perform in routine cases
– What they will do when you ask it to do something
• Within the IFU
• Outside the IFU

55. Endovascular Repair
• The technique is useful
• The results can be gratifying

56. Endovascular Repair
• However:
–Caution is required
–Recognition of potential problems
–There is still a lot we don’t understand

60. Dissection Stent

63. Endovascular Repair
• Or:

64. May 2012

65. Ongoing pain, aortic expansion, spikes severe HPTN

72. Endovascular Repair
• What are we still unsure about?
– The use and utility of uncovered dissection stents
– The use of TEVAR for ‘uncomplicated’ dissection
• Predictors where treatment is reasonable?
– What is the best device?

73. Bare Dissection Stents

74. Bare Dissection Stents

75. Endovascular Repair
• What are we still unsure about?
– The use and utility of uncovered dissection stents
– The use of TEVAR for ‘uncomplicated’ dissection
• Predictors where treatment is reasonable?
– What is the best device?

79. • Randomized Trial
• Acute Dissection <2 weeks
• BMT vs. TEVAR
• Primary End-Point
– False-lumen thrombosis at 1 year
– Aortic dilatation at 1 year
– Aortic rupture at 1 year
• Expect to enroll 250-260 patients
ADSORB

80. Endovascular Repair
• What are we still unsure about?
– The use and utility of uncovered dissection stents
– The use of TEVAR for ‘uncomplicated’ dissection
• Predictors where treatment is reasonable?
– What is the best device?

81. Endovascular Repair
• That is for another day

82. Thank You