Lessons Learned with TEVAR

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Lessons Learned with TEVAR
SAVS 2007 Thoracic Endovascular Aortic Repair
Christopher J. Kwolek, MD FACS Division of
Vascular and Endovascular Surgery Massachusetts
General Hospital
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Faculty Disclosure

• Christopher Kwolek, MD

• I disclose the following financial relationships
• Receive grant/research support
• Cook, WL Gore, Edwards, Cordis
• Advisory board of
• Medtronic, Boston Scientific

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THORACIC STENT GRAFT

• SPECTRUM PATHOLOGY

Saccular

• Degenerative aneurysm
• Acute/ ? Chronic Dissection
• IMH
• Penetrating ulcer
• Acute transection
• Pseudoaneurysm
• ? Shaggy aorta syndrome

Focal
Fusiform
vs
Diffuse
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THORACIC STENT GRAFT

• TIMELY

(J Vasc Surg 2005)
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Fundamentals of Endovascular Repair of DTA
Aneurysms

• Minimally invasive procedure
• Reliable delivery and deployment
• Hemostatic seal excludes DTA aneurysm from
  circulation
• Exclusion prevents DTA aneurysm rupture

? limited to descending aorta
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Pivotal Study (TAG 99-01)
Operative Results
30 days or In-Hospital Events

• TAG Device Surgical Control
• Operative Mortality 2
  11.7 ? p .003
• Paraplegia / paraparesis 3 14 ?
  p lt .001
• Stroke 4 4

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Pivotal Study (TAG 99-01)
Operative Results
140 Patients Enrolled

• 137 successful implantation (98)
• 3 failures due to poor iliac access
• 77 patients (55) required gt1 device
  to bridge the aneurysm
• 21 patients (15) had a conduit to the aortoiliac
  segment for access

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TAG Device Selection
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Trauma Arch Anatomy
18 yr. old
60 yr. old
20 yr. old
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2. Small aortic diameters (stentgrafts lt 20 mm Ø)
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3. Lesion close to left subclavian artery
Landing Zone lt 10 mm LSA overstenting 70
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Mid-device MMS
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Aortic Dissection
PATHOLOGIC ANATOMY
DISTAL DISSECTIONS

• Entry tear typically just distal to left
  subclavian artery. Rupture at entry site is RARE
  in absence of localized aneurysmal dilatation _at_
  entry tear. Anatomic foundation of medical Rx for
  distal dissections.

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Aortic Dissection

• CONTEMPORARY PERSPECTIVE

• IRAD study group results
• 12 academic medical centers
• nearly 500 patients treated 1996-1998

• Overall mortality ? 27
• Urgent asc. aortic graft ? 26 op mortality
• Distal dissections

(Hagan et al. IRAD, JAMA 2000)
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• Aortic Dissection

TREATMENT OPTIONS TYPE B

• Intervention indicated only for specific
  complications (for now)

Threatened proximal rupture (rare)
Branch compromise
Open/endovascular methods for directed peripheral
intervention, a complication-specific approach
Open repair
Stent graft
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• Aortic Dissection

ENDOVASCULAR FENESTRATION

• Minimally invasive alternative to surgical
  fenestration
• Complex endovascular procedure

Role of IVUS/adjuvant stenting

• Local expertise a definite factor!

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Infrarenal aorta fenestrated and right renal
perfused from true lumen
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• Aortic Dissection

ENDOVASCULAR FENESTRATION
RESULTS
Series Year pts Mortality Stanford 1999
40 25 Michigan 2001 50
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CAVEATS Age/vascular beds affected/ mesenteric
ischemia correlates of death
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STENT GRAFT REPAIR OF ACUTE DISSECTION
ANATOMIC PRINCIPLES
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STENT GRAFT CONSTRUCT FOR ACUTE DISSECTION
ROLE OF UNCOVERED STENTS
ENTRY TEAR
DISTAL BARE STENTS REMODEL AORTA
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HYBRID PROCEDURE
Aortic arch debranching
Distal ascending aorta becomes proximal seal zone
for stent graft
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CASE REPORT
ENLARGING ARCH/DESCENDING TAA

• 18 yrs s/p AAA
• Aneurysm begins mid arch with significant mural
  debris
• Staged hybrid procedure

Sternotomy Asc-Ao ? innominate/left CCA BPG 5
days later stent graft Asc ? distal thoracic aorta
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VISCERAL AORTIC SEGMENT
HYBRID PROCEDURE

• 73 yr. old female with limiting COPD and
  enlarging extent III TAA small AAA
• Stage one infrarenal graft with
  renals/SMA/celiac re-routing and conduit to left
  groin area
• Stage two stent graft thoracic aorta via conduit

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• Adopted B/O 20-30 mortality open TAA
• 25pts Rx 2002-05 (80 extent II, III)
• Elective mortality 17 ? no paraplegia

(J Vasc Surg 2006431081-9)
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Next Generation Devices

• Longer lengths
• Larger and smaller diameters
• More flexible devices and delivery systems
• Improved accuracy of proximal and distal
  deployment
• Mechanism to deal with risk of embolization
• Insitu mechanism to deal with arch and visceral
  branches
• System to integrate with percutaneous aortic
  valve repair
• Pathology specific devices which are more durable

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Tips and Tricks

• Pre and perioperative imaging is critical
• CTA 3D reconstruction
• Intraoperative angiogram with ability to obtain
  lateral and LAO views to visualize origins of
  visceral vessels, aortic arch
• IVUS for complicated cases (Dissection, complex
  anatomy, minimize contrast load)

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AXIAL IMAGING

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Tips and Tricks

• Intraoperative case planning (Set the table)
• Start with the easy cases
• Prepping and positioning, role underneath left
  flank, retroperitoneal access
• Access, Access, Access
• Have proximal and distal extensions, large
  balloons (Gore tri-fold, Coda, Medtronic)
• Z-Med balloon, large Palmaz stents

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Conduits

• Consequences if being overly aggressive with
  traditional access can lead to
• Femoral and iliac artery dissection or rupture
• Need for iliofemoral bypass grafting
• Having to do a conduit anyway
• Possible conversion to open surgical procedure
  
  
• Possibly death

Iliac artery on a stick
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OPEN VS. TEVAR -- MGH EXPERIENCE
(J VASC SURG 2006)
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THORACIC STENT GRAFT
POTENTIAL FOR DECREASED SPINAL CORD ISCHEMIA

No cases of spinal cord ischemia were noted
With n105 implants 4 (4.9) patients with
paraparesis/paraplegia
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ROLE OF ADJUNCTS

• CSF Drainage
• Adequate spinal cord perfusion pressure must be
  maintained
• Difference between mean arterial pressure and CSF
  pressure spinal cord perfusion pressure
• Spinal cord perfusion may be enhanced by lowering
  intrathecal pressure with use of CSF drainage

Is this extension from the surgical paradigm
logical in either a prophylactic or therapeutic
mode?
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Summary

• Paraplegia following endovascular repair of TAA
  does occur, but likely less risk than open repair
• Patients appearing at greater risk are those
  with
• Increased segmental treatment lengths
• Prior aortic replacement
• Concomitant abdominal aortic surgery
• True benefits of current prevention and treatment
  methods remains to be determined as more
  experience accumulates ? for now CSFD and
  arterial line (pressure) management best strategy
  for at-risk patients

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Thoracic Stent Graft Procedures-MGH
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