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Endovascular Repair of AAA
What are AAA?Management OptionsEndovascular Repair
ProcedureComplicationsPost-Operative Management
Anatomy RevisitedAbdominal aorta
Hiatus of diaphragm bifurcation into common iliac arteries (L4)
Paired and unpaired visceral branchesCommon iliac a.Internal iliac a.External iliac a.
Common femoral a (after passing below inguinal ligament)
AAA DefinitionLocalised dilatation of abdo aortaDiameter >50% of normal aortic diameter
Normal 2cm (1.4-3cm)>3cm considered aneurysmal
Up to 40% assd with iliac artery anuerysm
Indications for RepairSymptomatic
Tenderness, abdo or back painEmbolizationRupture
AAA ≥ 5.5cm>0.5cm expansion withing 6-months
Management OptionsOpen AAA repairEVARConservative
What is EVAR?Nicholas Volodos, Kiev, 1987Endovascular aneurysm repair
Folded graft components inserted through femoral artery into aorta and then deployed
Graft expands contacting the aorta wallExcludes aneurysm sac from aortic blood flow and
pressure
Suitable for 2/3 of pts with infrarenal AAA
Benefits of EVARAccounts for nearly half of all AAA repairsSignificant peri-op mortality
No open exposure or aortic clamping incidence of ruptured AAACan be offered to pts not suitable for open repair
DisadvantagesNot suitable for allCost
£3,000 - £10,000 more expensiveMay need conversion to open repairLifetime surveillance
?radiation riskDoes not completely eliminate future risk of rupture
AssessmentPre-Operative AssessmentTechnical Assessment
Pre-Operative AssessmentAs for open repairPOAC
IHD is leading cause of early & late mortalityCOPDRenal insufficency
Technical AssessmentCT angiography with 3-D reconstruction(Arteriography in emergencies)Measurements:
Aortic neck diameterAortic neck lengthAortic neck angulationInfrarenal aortic length
Common iliac a. DiameterRenal or artery anomalies
Technical AspectsAortic neck diameter
Size + 15-20% Sufficient radial forceOversize - Kinking, thrombus formn, endoleak
Aortic neck10-15mm (sufficient landing zone)Normal appearance
Aortic neck angulation<60°
Iliac ArteriesMinimal calcification / tortuosityNo stenosis or mural thrombusSufficient diameter & length
If external Iliac art. = landing zone, internal iliac art. should be embolised (prevent backflow)
Pre-Operative PreparationThromboprophylaxisProphylatic antibiotics
Cephalosporin or vancomycin for <24hrsPrevent Contrast-Induced Nephropathy
Procedure1. Anaesthetise 2. Gain vascular access3. Place guidewires & sheaths4. Confirm anatomy5. Main body deployment6. Gate cannulation7. Iliac limb deployment8. Graft ballooning9. Completion imaging
1. Anaesthetise GA, regional, LA with sedation
2. Gain vascular access Bilateral femoral access Surgical cutdown or percutaneous
3. Place guidewires & sheaths4. Confirm anatomy
Aortography
5. Main body deployment Proximal radiopaque markers Below renal artery
6. Gate cannulation Guidewire through contralateral femoral vessel Into graft gate
7. Iliac limb deployment (bilateral)8. Graft ballooning
Angioplasty of attachment sites and endograft junctions
9. Completion imaging Renal artery patency & exclude endoleak
Post-Operative CareWard careEat & drinkAnalgesiaIV fluids (prevent contrast nephropathy)D1 – mobileLOWER LIMB PULSE MONITORING
SurveillanceContrast CTADuplex US
1 month12 monthAnnual thereafter
ComplicationsRenal damage
IV contrast, emboliDVT/PE
5.3% develop DVT despite thromboprophylaxisMILower limb ischaemia/emboliEndoleak
ComplicationsOverall complication rate ~ 10%
Device-related Open conversion (<2%)
30-day all cause mortality:1.6% vs 4.8% (all)4.7% vs 19.2% (ASA IV)
3-4 year mortality equal
EndoleakType Aetiology
I Incompetent seal at proximal (Ia) or distal (Ib) attachment sites- Ongoing risk of rupture, correct promptly
II Flow into and out of aneurysm sac via patent branch vessels (lumbar, IMA)- 10-25%
III Separation of graft components (IIIa) or fabric tear (IIIb)- Ongoing risk of rupture, correct promptly
IV Egress of blood through fabric pores
V Continued aneurysm sac expansion without demonstrable leak
Thank You