Abdominal Aortic Aneurysms

Aurelia Thibonnier-Calero

PGY-2

Vascular Surgery

Types of Aneurysms True vs. False (pseudoaneurysm)

True: involves all 3 layers of the arterial wall

False: presence of blood flow outside of normal layers of arterial wall. Wall of false aneurysm is compose of the compressed, surrounding tissues.

Types of Aneurysms Etiology

Degenerative- complex process that involves some degree of calcification, atherosclerotic pathology as well as degeneration by MMPs.

Inflammatory- thick inflammatory wall with fibrotic process in retroperitoneum that can encase aorta as well as surrounding structures. Associated with other inflammatory conditions : Takayasu’s, Giant cell arteritis, Polyarteritis nodosa, Behcet’s, Cogans’.

Post-dissection- up to 20% of aneurysms are related to previous dissection. Overtime, develops into true aneurysm

Traumatic- false aneurysms Developmental Anomalies- persistent sciatic arteries, aberrant right

subclavian artery. Infectious- Can be primary or secondary infections. Congenital- Tuberous sclerosis, aortic coarctation, Marfan’s.

Crawford Aneurysm Type

Assessing the AAA patient Normal - aorta 1-2.4cm & iliac 0.6-1.2cm Aneurysm - Aorta >3cm & iliac > 2cm RF for aneurysm

Older age, male gender, white race, positive family history, smoking, HTN, hypercholesterolemia, PVD, CAD.

Ultrasound used to diagnose and monitor AAA until aneurysm

approaches size at which repair considered. Computed Tomography

used in preop assessment of AAA.

Ruptured AAA No significant overall change in mortality with

open repair from 1991-2006 Overall mortality for ruptured AAA = 90%

Mortality rate for patients who arrive at hosptial alive = 40-70%

High postop mortality rate due to MI, renal failure, and multi-organ failure Ischemia-reperfusion injury, hemorrhagic shock, lower

torso ischemia rEVAR significantly reduces mortality of ruptured

AAA patients (31 vs 50%)

Screening for AAA US Preventive Services Task Force

Men 65-75 yo who have ever smoked No for or against men 65-75yo who have never smoked Does not recommend screening for women

Society of Vascular Surgery, Medicare Screening Men who have smoked at least 100 cigarettes during

their life men and women with a family history of AAA

Only screen patients who are candidates for repair.

Choosing between Surgery & Observation

1. Risk for AAA rupture without surgery

2. Operative risk of repair

3. Patient’s life expectancy

4. Personal preferance of patient

1. Risk of Rupture Size matters:

Aneurysm > 5cm 6-16% and > 7cm 33% annual rupture rate

Wall stress analysis Saccular aneurysm have higher rate of rupture HTN, COPD, active smoking are independent

predictors of rupture (+) family hx tend to rupture Expansion rate

2. Operative Risk of Repair Mortality after:

elective open AAA ~ 5% EVAR 1%

6 independent RF’s for mortality Open repair Creatinine > 1.8, CHF, EKG detected ischemia,

Pulmonary dysfunction, older age, female gender. Cardiac, pulmonary, renal, and GI risks with

each proceudre.

3. Patient’s Life Expectancy Very difficult to assess due to patient’s

co-morbidities Typical 60yo surviving AAA repair has

13year life-expectacy, 70yo has 10year life-expectancy, and 80 yo has 6 year life-expectancy.

4. Personal Preference of Patient Fear of AAA vs. Fear of surgery Anecdotal experiences of friends and

family Procedures provided in community by

interventional specialists and surgeons.

Medical Management of AAA Smoking Cessation- Single most important modifiable risk factor Exercise Therapy- Evidence suggests may benefit small

aneurysms Beta Blockers- May decrease the rate of expansion? Important

cardiovascular effects thus use advocated. ACE inhibitors- Evidence is mixed, however, implicated in less

aneurysm rupture. Doxycycline

Antibiotic activiety against chlamydia species Suppresses expression of MMP

Statins - associated with reduced aneurysm expansion rates. Decreases MMP-9 in aneurysm wall.

EVAR vs. OPEN EVAR-1 and DREAM Trials

Randomized AAA > 5.5 cm to EVAR vs. open repair Lower 30-day mortality for EVAR (1.6% EVAR vs.

4.6% open) Peripop mortality and severe complications 4.7%

EVAR & 9.8% open repair (DREAM) Similar all-cause mortality at 2 years Higher rate of secondary interventions in EVAR

group Total cost of Tx & 4 years of f/u is significantly

increased for EVAR.

Open Repair Transabdominal Approach

Previous retroperitoneal surgery

Ruptured AAA Exposure of mid/distal

portions of visceral vessels or R renal artery

R internal or external iliac artery

Co-existant abdominal pathology

Left-sided vena cava

Retroperitoneal Approach

Mult. Previous intraperitoneal procedures

Abd wall stoma, ectopic/ anomaly of kidney

Inflammatory aneurysm Proximal aortic access,

endarterectomy of viceral/renal arteries needed

Obese patients Fewer GI complications

Open Repair-Complications Cardiac Pulmonary Renal Lower Extremity Ischemia Spinal Cord Ischemia Incisional Hernia

14.2% ventral hernia, 9.7% SBO Graft Infection

Open Repair Complications:Colon Ischemia

Collaterals from SMA, IMA, internal iliac artery, and profunda femoris supply sigmoid colon

Mortality 40-65%, full-thickness necrosis 80-100% Occurs in 0.6-3% of elective and 7-27% of ruptured

AAA (much more common endoscopically than clinically)

Si/Sx: persistent acidosis & shock, increased WBCs and lactate levels, fluid sequestration, bloody bowel movements.

TX: Ischemia limited to mucosa/submucosa- npo, IVF, IV abx Transmural ischemia- bowel resection, fecal diversion, creation

of ostomy, washout of abdomen, IV abx.

Open Repair- Concomitant Pathology Treat the most life-threatening process first Avoid simultaneous operations that increase the risk

for prosthetic graft infection If secondary procedure can be staged without

increased risk - do aneurysm repair first Clean procedures (ie:nephrectomy, oophrectomy) can

be performed simultaneously with open AAA repair GI procedures should not occur at same time as open

repair Abort surgery if metastatic disease or abscesses which

increase risk for graft infection discovered.

Inflammatory AAA Perianeurysmal fibrosis & inflammation 5% of AAA Treatment of AAA resolves the periaortic

inflammation in 53% (open & EVAR) Duodenum, left renal vein, and ureters often

involved in inflammation. PreOp ureteral stent placement

recommended.

Infected AAA 0.65% of AAA Can be primary or secondary infection Potential causes of infection:

Continguous spread of local infxn, septic embolization from distal site, bacteremia.

In the past syphilis and steptococcal species was common: Now: staph and salmonella.

With HIV and wide-spread abx use- can be caused by any bacterial or fungal infection

Dx: fever, abdominal/back pain, high ESR, bacteremia.

EVAR

Types of Endoleak

Types of Endoleak Type I

Usually identified and treated @ time of stent graft implantation Must be treated if found on post-op imaging Associated with high likelihood of AAA rupture Bridge with short aortic cuff, Palmaz stent

Type II 10-20% of post-op CT scan show Type II leak 80% resolve spontaneously at 6 months Indication to treat: persistent leak, aneurysm growth Transcatheter tx (coil embolization)

Type III 0-1.5% incidence Strong predictor of rupture Tx: re-establish continuity by additional component to bridge gap or cover

hole. Type IV

Majority resolve within one month of stent graft implantation

EVAR Complications:EuroSTAR Registry

Annual Incidence of Complication (per 1,000 patients)

From Van Marrewijk CJ, Leurs LJ, Valabhaneni SR, et al. Risk-adjusted outcome analysis of endovascular abdominal aortic aneurysm repair. J Endovasc Ther. 2005; 12; 417-429

AneuRx Ancure Excluder Talent Zenith

Type I & II endoleak

52 86 50 66 41

Migration 43 5 11 24 7

Graft Occlusion

19 33 11 23 35

Rupture 4 0 1 5 2

EVAR complications Stent-graft infection

Net infection rate of 0.43% Pelvic ischemia

Internal iliac occlusion during EVAR Si/sx: buttock claudication (most common

16-50%), buttock necrosis, colon necrosis, spinal ischemia, lumbosacral plexus ischemia, ED (15-17%).

Ischemic colitis < 2%

Long-Term Outcome of Open or Endovascular Repair of Abdominal Aortic Aneurysm

De Bruin et al.

DREAM study groupThe New England Journal of Medicine

May 2010

Introduction Previous studies have shown initial survival benefit in

patients undergoing EVAR vs. Open repair of AAA

Concern that EVAR is not as durable as AAA and is associated with greater risk of rupture and secondary interventions.

Goal: Analyze results of Dutch Randomized Endovascular Aneurysm Repair (DREAM) study to provide long-term data comparing open repair vs. EVAR

Methods Multicenter, randomized, controlled trial comparing open

repair vs. EVAR in 351 patients AAA > 5cm Patients had to be candidates for both techniques of

repair Exclusion Criteria:

Ruptured or inflammatory aneurysms, anatomical variations, connective-tissue diseases, hx of organ transplant or life-expectancy < 2 years.

F/U visits at 30 days, 6/12/18/24months after procedure After first 2 years, pts received questionnaires every 6

months.

Methods EVAR patient received CT scan annually All patients were called at 5 years and invited

for f/u CT scan. Data acquisition stopped Feb 2009 Primary outcome was rate of death from any

cause & reintervention Survival calculated on intention-to-treat basis.

Results November 2000-December 2003 178 patients Open repair vs. 173 EVAR Mean age 7yo, 91% male, 43.9% concomittant

cardiac disease. 6 pts did not undergo aneurysm repair

4 declined tx, 1 died from rupture, 1 died from PNA.

8 in hosptial deaths open vs. 2 EVAR Mean f/u 6.4 years 25% of open patient underwent CT scan at 5

years, 100% of EVAR

Results @ 6 years post-op:

Survival rate: 69.9% open, 68.9% EVAR Freedom from reintervention: 81.9% open vs.

70.4% EVAR Analysis of causes of death

EVAR- mostly miscellaneous rather than CV Reintervention

Open repair- majority done for hernia repair EVAR- endoleak, endograft migration

Discussion “No significant difference between

endovascular repair and open repair in rate of overall survival at a median of 6.4 years.”

Previously DREAM and EVAR-1 trials demonstrated early (2years) survival advantage for EVAR group.

Significantly higher rate of reinterventions in EVAR group than open group

Study limited by difference in f/u between the open and endovascular group.

Conclusion At 6 years, Open repair and EVAR have

similar rates of suvival EVAR has a greater rate of

reintervention

Total Percutaneous Access for Endovascular Aortic Aneurysm Repair (“Preclose” technique)

Lee WA, Brown MP, Nelson PR, Huber TS.

Journal of Vascular Surgery 2007 June; 45(6):1095-101

University of Florida, Gainesville

large single institutional experience with the method and outcomes of a variation of the Preclose technique using the 6F Perclose Proglide (Abbott Vascular) device during endovascular aortic repairs.

Retrospective review of patient who underwent EVAR/TEVAR from Oct 03-Aug06

183 perc femoral access with 12-24F Perclose technique with Proglide device compared to 154 patients with open surgical exposure of femoral arteries

Anesthia used for Preclose vs. open: general, 49% vs 55%; regional, 45% vs 44%; and local, 5% vs 1% (P = .10).

Percutaneous group broken down into group of smaller 12-16F and group of larger 18-24F sheaths.

Data points: perioperative outcomes, procedure times, operating room usage costs, and technical success (in-hospital or 30-day).

F/U: CT scan at 1 month post-op The list price for each Perclose Proglide device is (US) $295.

Dilator set $170.44 cost of the operating room is (US) $3935 for the first 60 minutes

(not prorated for shorter periods) and then $50/min thereafter.

Results 137 EVAR, 118 TEVAR, 7 iliac repairs performed 381 femoral arteries accessed with 12-24F sheaths

279 were with 559 Proglide devices using Preclose technique in 183 patients

4 femoral artereries required 1 device (1.4%) -all 12F sheaths

270 arteries (96.8%) required 2 devices 5 arteries (1.8%) required 3 devices 63% of sheaths were > 18F

Overall technical success of Preclose technique was 94.3%

99% for smaller sheaths and 91% for larger sheaths.

Results 16 complications

13 open repairs of femoral arteries 2 emergent placement of covered stent for severe

retroperitoneal hemorrhage. 1 necrotizing arteritis with mycotic

pseudoaneurysm requiring replacement of femoral artery with autogenous femoral vein.

All cause mortality 2.2% Access mortality 0%

Results Surgical Group- 154 endovascular repairs

108 EVAR and 46 TEVAR 258 femoral exposures

Technical success rate 93.8% 16 complications

10 endarterectomies with patch angioplasty 3 wound infections 2 infected seromas requiring I&D 1 severe arteritis requiring debridement and replacement

of CFA with autogenous femoral vein. All cause mortality 1.3% 0% access-related mortality

Results Significantly lower OR time for Preclose

group: EVAR: 115 vs 128 min TEVAR: 80 vs 112 min

Cost: OR + Proglide vs. OR+ Surgery EVAR: $7881 vs $7351 TEVAR: $5679 vs $6556

Discussion Percutaneous Access

Shorter procedure time Fewer wound complications Increased patient comfort Limited by size of delivery system.

In this study: Smaller sheaths had higher technical success All complications occurred intra-op No access-related mortality Accessing anterior aspect of mid-common femoral artery is

crucial in preventing hemorrhagic complications.

Discussion Contraindications to Preclose:

Coagulopathy is contra-indication to use of this device due to inability to control “needle-hole bleeding”

Severe calcifications Groin scarring Obesity Previous use of percutaneous closure devices. High (suprainguinal ligament) femoral bifurcation Need for frequent introducer sheath removals and insertions Proximal iliac occlusive disease Small iliofemoral arteries relative to profile of device being

used

Conclusion Prospective, randomized study is

needed to truly validate this technique Percutaneous EVAR is safe and

effective Long-term data is needed to evaluate

effect on femoral artery.

The End