EVAR Flashcards
What French can 1 and 2 percloses accommodate?
8; 21
What are benefits of EVAR over Open?
Periop mortality improved w EVAR (EVAR 1, DREAM, OVER): <2% vs 5% Survival benefit lost after 2-3 years (EVAR 1, OVER) 6 year survival similar ~70% (OVER)
What are 5 disadvantages of EVAR vs Open?
More expensive (EUROSTAR) More reinterventions (OVER): 30% vs 20% at 6 yrs More reinterventions per year (EUROSTAR): 5% per yr Continued sac expansion/rupture rate (EUROSTAR): 40% at 5 yr, 1% per yr despite EVAR 50% lost to follow up at 5 yr
Which trial compares EVAR vs medical management?
EVAR 2
What was the final conclusion of EVAR 2?
No difference in aneurysm related or all cause mortality between EVAR and Med managment in pats who were medically unfit for open repair
What is the risk of death for pts who undergo treatment for ruptured AAA
~ 35% at 30d (IMPROVE)
What are 4 advantages of EVAR vs Open for ruptured AAA?
IMPROVE Improved 3 year survival (48% vs 56%) Shorter hospital stay Lower cost Better QALY Similar reinterventions rate
Which graft brand has the highest rate of limb occlusion?
Zenith Cook - EUROSTAR
Which graft has the highest rates of migration?
AneuRx and Talent
Name 5 ways of treating a type 1a endoleak
- Proximal extension - Embolization w glue/coils - Palmaz - EndoStapling - Hemashielf patch aortic wrap
How frequent are type 2 endoleaks?
10-20% of EVARs
Name 5 ways of managing type 2 endoleak
- Watch and wait, 80% spontaneously resolve - Embolize with coil or glue via SMA/marginal Drummond, or slipping wire in between stent and iliac limb - Translumbar direct sac puncture - Retroperitoneal endoscopic ligation - Explant or direct ligation of back bleed vessels
Name 4 anatomic risk factors for EVAR migration
- Angulated neck - Short neck - Neck thrombus - Large diameter neck
What is the minimum neck length for a seal?
10-15 mm
What neck angulation is acceptable for EVAR?
< 60 degrees
Which stent is approved for neck angulation up to 90 deg?
Aorfix (Lombard)
What is the risk of EVAR limb occlusion?
3-7 %
What are 3 risk factors for EVAR limb occlusion?
Aortoiliac disease Small distal aorta < 14mm Tortuous iliac EVARs that land in external iliacs
How frequently do EVARs become infected?
Rarely <1%
How frequent is buttock claudication after EVAR?
Frequent. ~50%, higher when internals are embolized
What is the risk of erectile dysfunction following EVAR?
17% overall, up to 25% with bilateral internal iliac embolizations
Which imaging studies do you do to follow EVAR patients?
SVS guidelines: CTA at 1 month and 1 year If endoleak detected at 1 month, repeat in 6 months After 1 year, annual duplex.
What is the largest iliac seal zone diameter?
25 mm (28 is largest iliac limb diameter, Medtronic)
Which costs more - EVAR or Open?
Operative - EVAR Overall with length of stay - Open OVER trial - EVAR costs $37k vs Open 43k, benefit not significant after 2 years
What is the mortality rate of rAAA in hospital?
40%
What is the role of aortic thrombus in rupture
Weakens the wall - blocks wall from nutrients/hypoxia, MMP increased activity and increase vascular smooth muscle cell production of collagenase
Name 6 differentials for rAAA?
- Diverticulitis
- Renal colic
- Perforated ulcer
- MI
- GI bleed
- Pancreatitis
Is there time for a CT scan for a rAAA?
Yes. IMPROVE > 90% had CT scans. Avg 16 h to die.
Name 5 reasons why you should avoid crystalloid boluses for rAAA
- Reduce tamponade and increase bleeding
- Coagulopathy
- Hypothermia
- Acidosis
- Hemodilution
Should you use general anesthesia or local for ruptured EVAR?
Local - IMPROVE showed better 30 day survival
When should you suspect an aortocaval fistula during rAAA?
Persistent venous bleeding into the aneurysm after proximal and distal control
How do you repair an aortocaval fistula?
Sponge sticks for control, ligate from within the opened aortic sac
Define abdominal compartment syndrome
Elevation of abdominal pressure by 20 mm Hg with end organ dysfunction (resp, cardiac, renal or splanchnic)
What bladder pressures are indication for laparotomy?
Above 25 mm Hg
What are 4 signs/symptoms of abdominal compartment syndrome
- Resp - increased PEEP, decreased tidal volume, elevated PCO2
- Oliguria
- Tense abdomen
- Decreased cardiac output
What percentage of people experience a cardiac arrest with rAAA repair?
20%
What is the 2 hit hypothesis?
Hemorraghic shock + aortic clamping required for MOF. Either one on its own won’t cause such profound MOF
Name 3 RCTs comparing EVAR and open rAAA repair
- ECAR
- AJAX
- IMPROVE
What were the key 3 year outcomes of IMPROVE?
EVAR better - mortality, shorter LOS, cheaper, discharged home, local had survival benefit
Which stent graft is this?
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Endologix AFX
Which stent graft is this?
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Medtronic Endurant
Which stent graft is this?
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Gore Excluder
Which stent graft is this?
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Lombard Aorfix
Which stent graft is this?
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Trivascular Ovation
Which stent graft is this?
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Cook Zenith
Which graft should you use for an AAA with a short or angulated neck?
Lombard Aorfix only one approved
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What are 3 relative indications for Aortouni EVAR?
1 - Very small < 15mm bifurcation
2-Severe unilateral iliac occlusive disease
3 - Treatment of migration of short body endograft
If you have to plan an EVAR based off of non contrast CT, what 3 things are you missing?
1 - laminated thrombus in aortic neck
2 - patency of important branches e.g. internal iliacs
3 - potential occlusive disease in access vessels.
Which devices require you to measure intima to intima?
Gore. All others are adventitia to adventitia
Which EVAR stent grafts are cobalt chromium based?
Endologix AFX
Which EVAR stent grafts are stainless steel based?
Cook
Which EVAR stent grafts are nitinol based?
Medtronic, Gore, Ovation, Aorfix
Which EVAR stent grafts have suprarenal fixation?
Cook Zenith, Medtronic Endurant, Trivascular Ovation
Which EVAR stent grafts have infrarenal fixation?
Gore excluder, Endologix can be infra or suprarenal, Lombard Aorfix
Which EVAR stent grafts have the lowest profile?
Gore excluder - 16F main body, 12F limb
Ovation - 14F main, 12F limb
AFX 19F main/9F limb
(In comparison - Cook = 21F main 14F limb, Medtronic 18F main 14F limb)
Which EVAR stent graft is repositionable?
Gore Excluder
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Which graft should you use if aneurysm has a 10mm neck?
Medtronic Endurant
How much should EVAR aortic neck be oversized?
10-20% (3-4mm)
What is the range of neck diameters that EVARs can accommodate?
16-32mm
What diameter measurement do you use for conical necks?
Split the difference. 10% over larger diameter, 30% smaller diameter. If there is more than 3-4mm conical change in the first 15mm, EVAR not advisable
Do centreline measurements under or over estimate length needed?
Overestimate in cases with extreme tortuosity or if balleting the limb
What are advantages of percutaneous EVAR?
3 RCTs, metanalysis
1 - Shorter procedure time
2-Lower postop pain
3-Shorter hospital stay
4- Less wound complications including infection and lymphocele
What are disadvantages of percutaneous EVAR?
Higher cost of procedure. Occasional conversion to open.
Name 6 relative contraindications to percutaneous EVAR
1 - Heavy anterior calcified plaque
2 - Severely scarred groin
3 - High femoral bifurcation
4-Need for multiple introducer sheath changes
5-Small iliofemoral
6-Significant proximal iliac disease
Name 5 ways of addressing small iliacs when putting up an EVAR
1 - coons dilators
2 - focal stenoses - angioplasty
3 - “internal endoconduit” = put up a covered stent and aggressively balloon
4 - balloon expandable sheath
5-iliac conduit
What rate/amount do you need for the initial aortogram using a power injector
“10 for 20” - 10 mL total contrast, 20 ml/s rate
What are your options if you cannot cannulate the contralateral gate?
1-antegrade from brachial and snare
2-up and over snare
3-convert to aortouni
What is the absolute minimum iliac seal zone?
2 cm
What percentage of AAA repairs in US are done by EVAR?
90%!
What are the zones of the thoracic aorta?
0 - between innominate and L CCA
1 - between L CCA and L SCA
2 - L SCA
3 - beyond L SCA
4 - beyond arch
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Which zones thoracic aorta should have open repair? which should have TEVAR?
0, 1 - open
3, 4 - TEVAR
(2 TEVAR w carotid subclavian bypass or transposition.)
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What are the anatomic size requirements of the native aorta to permit TEVAR?
Native aorta - 16-42 mm
How long do sealing zones need to be to permit TEVAR?
2 cm
What size do iliacs need to be to accomodate a TEVAR?
5-10 mm depending on device
What are your options for TEVAR deployment when iliacs are too small?
Retroperitoneal “transplant” incision, or laparotomy to put conduit on aorta or common iliacs
What 2 bypass options are available to do a Zone 1 TEVAR?
1) Right to Left carotid carotid bypass + left carotid to left subclavian bypass
2) Right subclavian to left subclavian + left subclavian to left carotid
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What are 2 approaches for a Zone 0 TEVAR?
1) Median sternotomy + proximal ascending aorta to left subclavian bypass + extra-anatomic bypass. benefit - do not require cardiopulmonary bypass
2) chimney technique - maintain flow to innominate artery by deploying from right brachial at same time as TEVAR deployed.
What are the 2 major limitations of using a chimney technique for zone 0 TEVAR
1 - gutters
2 - can collapse the innominate branch - the sole branch providing perfusion to the brain - fatal
What are 3 limitations of laser fenestration in the aortic arch to facilitate zone 0 TEVAR?
1 - holes may not line up
2 - potential trauma to aortic arch
3 - this modification to graft may cause type 2 endoleak
Which 4 aortic arch zone 2 TEVARs with branches are available?
1) Gore c-tag: precannulated side branch for left subclavian
2) Medtronic Valiant - flexible LSCA external cuff - not precannulated
3) Relay plus double branch arch - two parallel tunnels to cannulate and revasc innominate and left CCA, still require carotid to subclavian bypass
4) Cook Zenith 2 side branches for innominate and L CCA with 4 trigger wires
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What are the Cook IFU for fenestrated device?
1-non aneurysmal infrarenal neck of 4mm
2-prox neck diameter of 19-31mm
3 - angulation < 45 degrees
4 - 3 cm distal landing zone
5 - adequate access
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What is a p-branch device?
Fenestrations with outpouchings to allow for pivot points and a bit more flexibility than fenestrations.
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What is a t-branch device?
Tapered stent graft sockets for the visceral vessels
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What is the primary drawbac of T-branch devices?
Delivery system requires 20F sheath
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