Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA)

Abdominal aortic aneurysm (AAA)

endovascular repair associated with lower morbidity and mortality than open repair (N Engl J Med 2008 Jan 31)

Description:

abnormal dilatation of blood vessel

aneurysm = diameter 2 times normal lumen above and below

Also called:

atherosclerotic aortic aneurysm

Types:

atherosclerotic AAA is most common type

inflammatory AAA

variant of atherosclerotic AAA

dense fibrotic reaction of anterior and lateral walls of aneurysm and surrounding tissues (frequently duodenum)

associated with retroperitoneal fibrosis

surgical repair of inflammatory AAA

surgery more difficult due to inflammatory peel and many adhesions

mobilization of aneurysm may damage duodenum

patients tend to have more pain than with typical AAA

inflammation frequently recedes after repair

case presentation of inflammatory AAA can be found in Mayo Clin Proc 2002 Aug;77(8):849 full-text mycotic AAA

bacterial inflammation of arterial wall

most commonly Salmonella in infrarenal aorta

patient may have fever and evidence of septic embolization

blood tests may show increased WBC, positive blood cultures

aneurysm usually sacular, lacking calcifications

long-term antibiotics should be directed by culture and sensitivities

surgical exploration

if no periaortic purulence and negative Gram stain of proximal and distal artery - interposition of graft may be sufficient

if gross purulence - resection, close aorta, extra-anatomic (axillobifemoral) bypass

ruptured AAA

immediate surgical emergency

clinical diagnosis - consider as diagnosis until ruled out in any patient with hypotension, abdominal pain and palpable mass, shock

maintain systolic blood pressure 50-70 mmHg until aorta clamped

Organs Involved:

descending aorta, 75-95% infrarenal

Who is most affected:

advancing age, men

Incidence/Prevalence:

prevalence of AAA

varies from 1.3% to 8.9% in men and 1% to 2.2% in women (Lancet 2005 Apr 30;365(9470):1577)

varies from 2% to 7.8% (Ann Intern Med 1993 Sep 1;119(5):411 full-text)

prevalence of AAAs 2.9-4.9 cm varies with age, gender, family history and tobacco use

typical prevalence in men ranges from 1.3% at ages 45-54 years to 12.5% at ages 75-84 years

typical prevalence in women ranges from 0% at ages 45-54 years to 5.2% at ages 75-84 years

Reference - ACC/AHA 2005 guidelines (J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF)

prevalence of ruptured AAA

cause of death annually for about 1.2% males and 0.6% females > 65 years old

21-66% of patients survive to surgery, with 50% mortality following surgery

Reference - Ann Intern Med 1993 Sep 1;119(5):411 full-text HYPERLINK "javascript:changeView(%22Causes_and_Risk_Factors%22);"

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Causes and Risk Factors

Causes:

> 95% cases due to atherosclerosis in United States

mycotic AAA due to bacterial infection, most commonly SalmonellaPathogenesis:

intimal dissection causes aortic dilatation and creation of false lumen

Likely risk factors:

smoking

clinical vascular disease

male

older age

increased blood pressure

increased total cholesterol

family history of AAA

Reference - based on 6 cohort studies

Click for Details smoking most important risk factor, based on a cross-sectional screening study of 73,451 veterans 50-79 years old

1,031 (1%) had AAA > 4 cm on ultrasound

smoking increased risk almost 6x, risk increased with duration and smoking and decreased with duration of quitting

other risk factors included older age, family history, atherosclerosis, hypertension, high cholesterol

Reference - Ann Intern Med 1997 Mar 15;126(6):441 in J Watch 1997 Apr 15;17(8):63

risk factors for AAA include smoking, older age, family history of AAA, atherosclerotic diseases, male sex; while diabetes and black race negatively associated with AAA

52,745 veterans ages 50-79 years without history of AAA underwent successful ultrasound screening for AAA

AAA > 4 cm detected in 613 (1.2%), results consistent with 1.4% detection rate in earlier cohort of 73,451 veterans

odds ratios for major associations with AAA for combined cohorts (total population of 126,196) were

5.07 for smoking

1.94 for family history of AAA

1.71 for age (per 7 years)

1.66 for atherosclerotic diseases;

0.53 for black race

0.52 for diabetes

0.18 for female sex

excess prevalence associated with smoking accounted for 75% of all AAAs > 4 cm

Reference - Arch Intern Med 2000 May 22;160(10):1425 classic risk factors for atherosclerotic diseases associated with AAA

based on a cohort of 29,133 Finnish male smokers, aged 50-69 years

mean follow-up 5.8 years

risk of AAA associated with

age (relative risk 4.56, 95% CI 2.42-8.61 for > 65 vs. 55 years)

smoking years (relative risk 2.25, 95% CI 1.33-3.81 for > 40 vs. 32 years)

systolic blood pressure (relative risk 1.92, 95% CI 1.13-3.25 for > 160 vs. 130 mmHg)

diastolic blood pressure (relative risk 1.8, 95% CI 1.05-3.08 for > 100 vs. 85 mmHg)

serum total cholesterol (relative risk 1.85, 95% CI 1.09-3.12 for > 6.5 vs. 5 mmol/L [> 250 mg/dL vs. 193 mg/dL])

Reference - Epidemiology 2001 Jan;12(1):94 smoking, male sex and hypertension are risk factors for AAA

based on cohort of 5,356 men and women aged 65-79 years participating in randomized trial

current hypertension associated with 30-40% increased risk of AAA while use of antihypertensive medication associated with 70-80% increased risk

men were nearly 6x more likely to develop AAA than women

smoking was an independent risk factor for AAA, with level of exposure more significant than duration

Reference - Br J Surg 2000 Feb;87(2):195 clinical vascular disease strongly associated with AAA

based on prospective study of 4,741 patients > 64 years old

ratio of transverse diameter of maximum infrarenal aorta and aorta just below superior mesenteric artery, defined as I/S ratio; AAA defined as I/S ratio 1.2

overall incidence of AAA 9.5%, with 14.2% in men and 6.2% in women

risk factors for AAA include age, male sex, coronary artery disease, peripheral vascular disease, carotid occlusive disease, smoking and elevated LDL levels

no relationship found between blood pressure and presence of AAA, although patients treated for hypertension more likely to have AAA

Reference - Arterioscler Thromb Vasc Biol 1996 Aug;16(8):963 in QuickScan Reviews in Fam Pract 1997 Feb;21(11):11

family history associated with increased risk, especially for older male relatives of persons with AAA

study of 214 living relatives > 50 years old of 150 consecutive patients undergoing repair of infrarenal AAA vs. 284 controls

comparing persons with family history of AAA vs. controls

4.6% vs. 1.4% had AAA > 3 cm detected by ultrasound or had prior AAA repair

1.2% vs. 0 had aortic dilatation (2-2.9 cm)

Reference - Ann Intern Med 1999 Apr 20;130(8):637 in J Watch 1999 Jun 1;19(11);87, summary in Am Fam Physician 1999 Sep 15;60(4):1234Complications:

rupture

erosion of adjacent structures

embolization, thrombosis

fistulization, including aortocaval fistula (high-output congestive heart failure)

disseminated intravascular coagulation (DIC) reported in 3% to 4% patients having surgery for AAA

DIC reported in 2 of 67 (3%) patients having surgery for AAA (Ann Vasc Surg 1996 Jul;10(4):396)

DIC reported in 3 of 76 (4%) patients having surgery for AAA (Arch Surg 1983 Nov;118(11):1252)

Associated conditions:

coronary artery disease -- AAA associated with increased incidence of cardiovascular disease and mortality

based on cohort of 4,734 men and women > 65 years old followed for 4.5 years

8.8% had AAA (88% of which had 3-3.5 cm diameter)

comparing persons with vs. without AAA

all-cause mortality 6.51 vs. 3.28 per 100 person-years

cardiovascular mortality 3.43 vs. 1.38 per 100 person-years

incident cardiovascular disease 4.73 vs. 3.1 per 100 person-years

Reference - Ann Intern Med 2001 Feb 6;134(3):182 arterial infection with Salmonella cholerasius or S. typhimurium

iliac artery aneurysm (extension of AAA, pulsatile mass on rectal exam, occasionally ruptures into gastrointestinal tract)

inguinal hernias in men, possibly related to degeneration of connective tissue (Br J Surg 1999 Sep;86(9):1155 in BMJ 1999 Oct 2;319(7214):930)

History

Chief Concern (CC):

usually asymptomatic until rupture

symptoms may include abdominal pain, low back pain, leg ischemia, flank pain, claudication, impotence

rupture may present with acute epigastric and back pain with syncope or shock

History of Present Illness (HPI):

mid-abdominal or flank pain which may radiate to back, groin or scrotum

sudden onset of pain may suggest rupture

Past Medical History (PMH):

hypertension, diabetes mellitus, COPD, coronary artery disease

Family History (FH):

can be familial (X-linked most common, also autosomal dominant), but same groups have atherosclerosis

Social History (SH):

smoking

Physical

General Physical:

normal vital signs may be present initially with rupture, but patients can become severely hypotensive rapidly

Abdomen:

usually presents as asymptomatic palpable pulsatile nontender mass, bruits

abdominal palpation

clinical exam may not be reliable to rule out AAA, especially in obese patients

based on literature review

sensitivity of physical exam ranges from 33% to 100%

specificity ranges from 75% to 100%

positive predictive value ranges from 14% to 100%

Reference - Accid Emerg Nurs 2004 Apr;12(2):99 abdominal palpation technique

patient in supine position with knees raised and abdominal muscles relaxed

aortic pulse palpated just above and to left of umbilicus

width of aorta measured by placing both hands palms down on patient's abdomen, with index fingers on either side of aorta

each systole should move fingers apart

width of aorta more important than intensity of pulsation

ultrasound warranted if aortic diameter > 2.5 cm

Reference - JAMA 1999 Jan 6;281(1):77 in Am Fam Physician 1999 Apr 15;59(8):2343 abdominal palpation for detecting AAA has limited sensitivity and specificity

based on pooled analysis of 15 studies of patients screened for AAA with both abdominal palpation and ultrasound

sensitivity of abdominal palpation was 29% for AAAs 3-3.9 cm, 50% for AAAs 4-4.9 cm and 76% for AAAs > 5 cm diameter

43% positive predictive value for AAA > 3 cm

limited data suggest that abdominal obesity decreases sensitivity

abdominal palpation was only physical exam maneuver demonstrated to be of value in detecting AAA

abdominal palpation appears to be safe and not reported to precipitate rupture

abdominal palpation cannot be relied on to rule out AAA, especially if rupture is a possibility

Reference - JAMA 1999 Jan 6;281(1):77, commentary can be found in JAMA 1999 Jun 2;281(21):1989 abdominal palpation has only moderate sensitivity for detecting AAA

based on study of 2 of 3 internists examining 99 persons ages 51-88 years known to have AAA and 101 persons without AAA on ultrasound

abdominal palpation had 68% sensitivity, 75% specificity, positive likelihood ratio 2.7, and negative likelihood ratio 0.43

77% interobserver pair agreement (kappa = 0.53)

100% sensitivity for the 6 patients with abdominal girth < 100 cm and AAA > 5 cm

Reference - Arch Intern Med 2000 Mar 27;160(6):833, commentary can be found in ACP Journal Club 2001 Jan-Feb;134(1):30

periumbilical ecchymosis (Cullen's sign) and ecchymosis over the flanks (Turner's sign) may occur with any process causing hemoperitoneum and has been reported in patients with hemorrhagic pancreatitis, retroperitoneal hemorrhage, splenic rupture, ruptured ectopic pregnancy, leaking aortic aneurysm, lymphoma, hepatocellular carcinoma and liver metastases (N Engl J Med 1999 Jan 14;340(2):149)

Extremities:

inequality of femoral pulses

signs of peripheral emboli

Diagnosis

Making the diagnosis:

abdominal ultrasound or other imaging

Rule out:

inferior wall myocardial infarction

nephrolithiasis

diverticulitis

pancreatitis

mesenteric ischemia

acute cholecystitis

other causes of acute abdomen

Testing to consider:

ultrasound can define length and diameter of aneurysm

computed tomography (CT) if stable and doubtful diagnosis

magnetic resonance angiography (MRA)

electrocardiography (ECG)

Imaging studies:

AAA may appear as incidental finding on abdominal x-ray (stippled calcifications to left of spine)

ultrasound

B-mode ultrasound most practical, cost-effective for serial size

portable ultrasound in emergency department might improve diagnostic certainty but no reliable evidence for impact on clinical outcomes

systematic review found only 1 case series for abdominal aortic aneurysm

portable ultrasound reported to have 100% sensitivity

estimated positive likelihood ratio 14.6 and negative likelihood ratio 0.06 for abdominal aortic aneurysm

no studies reported mortality rates

no studies reported complication rates, time to diagnosis or time to operative treatment for patients with abdominal aortic aneurysm

Reference - CCOHTA technology report 2006 Mar:63 PDF Finnish Medical Society Duodecim evidence-based guideline on indications and preparation of patient for ultrasonographic examinations can be found at National Guideline Clearinghouse 2007 Mar 19:10478 computed tomography (CT)

CT can detect retroperitoneal rupture

CT may show suprarenal extension and other abdominal abnormalities which may influence aneurysm repair

CT estimates of AAA size are larger than ultrasound estimates

based on an analysis of 334 patients in national endograft trial who had both CT and ultrasound measurements

maximal AAA diameter ranged from 4-8 cm on CT

CT measurements exceeded ultrasound measurements in 95% of cases

average difference 0.94 cm, discrepancy increased as AAA size increased

Reference - J Vasc Surg 2003 Sep;38(3):446 in J Watch Online 2003 Oct 21

angiography useful for patients with hypertension secondary to renal artery stenosis, distal arterial occlusive symptoms, or suspected mesenteric ischemia

review of imaging of AAA can be found in Am Fam Physician 2002 Apr 15;65(8):1565

American College of Radiology (ACR) Appropriateness Criteria for pulsatile abdominal mass can be found in National Guideline Clearinghouse 2006 Mar 20:8293, previous version can be found in Radiology 2000 Jun;215(Suppl):55

American College of Radiology (ACR) Appropriateness Criteria for palpable abdominal mass can be found at National Guideline Clearinghouse 2006 Sep 4:9595

Prognosis

Prognosis:

15-20% show no increase in size, > 80% progressive enlargement, 15-20% grow > 0.5 cm/year

some aneurysms quiescent for months to years then sudden increase

large aneurysms usually grow more rapidly

any aneurysm may rupture, risk increases with size

aneurysms growing > 0.5 cm/6 months tend to rupture

retroperitoneal ruptures may be contained but can blowout at any time

risk of rupture in 5 years - < 4.5 cm 9%, 4.5-7 cm 35%, > 7 cm 75%

risk factors for rupture include larger AAA diameter, female sex, higher mean arterial blood pressure and current smoking

based on ultrasound surveillance of 2,257 patients with 4,102 patient-years of follow-up

103 episodes of AAA rupture

number of ruptures per 100 patient-years was 0.3 for AAAs < 4 cm, 1.5 for AAAs 4-4.9 cm and 6.5 for AAAs 5-5.9 cm

Reference - Ann Surg 1999 Sep;230(3):289 in J Watch 1999 Oct 15;19(20):157 or in Am Fam Physician 2000 Feb 1;61(3):875 aneurysm size is a strong predictor of risk of rupture and based on professional association guidelines

estimated annual risk of AAA rupture

< 4.0 cm (0%)

4.0 to 4.9 cm (0.5% to 5%)

5.0 to 5.9 cm (3% to 15%)

6.0 to 6.9 cm (10% to 20%)

7.0 to 7.9 cm (20% to 40%)

8.0 cm (30% to 50%)

5.5 cm considered best threshold for repair in "average" AAA patients

Reference - American Association for Vascular Surgery and Society for Vascular Surgery guidelines (J Vasc Surg 2003 May;37(5):1106)

AAA > 5-5.5 cm has high rupture rate if untreated (i.e. patients unfit for surgery)

based on 3 cohort studies

prospective study of 476 patients (mean age 73 years) with AAA > 5 cm initially considered unfit for surgery

CT performed every 6 months for mean 4 years

173 eventually had elective surgery

50 (10.5%) had rupture of AAA

annual rupture rate for AAAs 5-5.9 cm were 1% for men and 4% for women

annual rupture rate for AAA 6 cm or larger 14% for men and 22% for women

Reference - J Vasc Surg 2003 Feb;37(2):280 in J Watch Online 2003 Mar 18

study of 198 veterans with AAA at least 5.5 cm who refused or were unfit for elective AAA repair


112 (57%) died and almost half had autopsy

45 patients (23%) had probable AAA rupture

1-year incidence of probably AAA rupture by diameter was 9.4% for 5.5-5.9 cm, 10.2% for 6-6.9 cm (19.1% for 6.5-6.9 cm) and 32.5% for 7 cm or greater

25.7% AAAs 8 cm or greater ruptured within 6 months

Reference - JAMA 2002 Jun 12;287(22):2968 study of 57 patients (mean age 81) with AAA > 5 cm who were considered unfit for surgery (e.g. cardiovascular disease, poor functional status, malignancy) and followed at least 2 years

estimated 3-year rupture rate was 28% for AAA 5-5.9 cm and 41% for AAA > 6 cm

median survival 18 months with 19 deaths from ruptured AAAs and 31 deaths from other causes

Reference - Br J Surg 1998 Oct;85(10):1382 risk of rupture low for aneurysms < 5 cm and varies with size

study of 176 patients with small AAAs followed with Doppler ultrasound for 8 years

24% patients with AAA < 5 cm underwent elective repair

none of 55 AAAs < 3.5 cm ruptured

5% of 75 AAAs 3.5-4.9 cm ruptured

25% of 46 AAAs > 5 cm ruptured

Reference - N Engl J Med 1989 Oct 12;321(15):1009 in Cortlandt Forum 1997 May;10(5):94,111-6

AAA size at last ultrasound predicts risk of AAA rupture

176 patients (mean age 74) with unruptured AAA followed mean 5 years

82 had elective surgery, 11 had rupture, 97 died of other causes

no AAA < 4 cm on last ultrasound ruptured

rupture risk 1%/year for AAAs 4-5 cm and 11%/year for AAAs 5-6 cm

Reference - Arch Intern Med 1997 Oct 13;157(18):2064 in J Watch 1997 Nov 15;17(22):173

small AAAs typically expand at rate of 1-2 mm/year

based on 2 cohort studies

retrospective study of 1,445 men with AAA 3-3.9 cm on screening ultrasound

790 had at least one follow-up ultrasound during mean follow-up 3.9 years

median rate of AAA expansion was 0.11 cm/year

expansion to 5 cm or greater occurred in 6.7% AAAs (4% those 3-3.4 cm, 14% those 3.5-3.9 cm)

no ruptures reported but completeness of follow-up unclear

authors recommend waiting 3 years for follow-up ultrasound for AAAs 3-3.9 cm

Reference - J Vasc Surg 2002 Apr;35(4):666 in J Watch Online 2002 May 14)

cohort study of 41 patients with AAA of median diameter 3.3 cm (range 2.4-4 cm)

median follow-up 7 years (range 1.4-11.6 years)

median linear expansion rate 2 mm/year (range 0-8.4 mm/year) with higher rate associated with larger AAAs

3 patients (7.3%) had rupture, 13 patients (32%) had repair

59% survival at 10-year follow-up (70% survival in patients without repair or rupture)

Reference - Am J Surg 2002 Jan;183(1):53 in Am Fam Physician 2002 May 15;65(10):2128 risk factors for mortality with repair of non-ruptured AAA may include

age > 75 years

female gender

history of previous myocardial infarction

symptomatic course of AAA

insufficient respiratory function

insufficient renal function

Reference - prospective study of 69 patients who had AAA resection for non-ruptured AAA, 8 (11.6%) died within 30 days after surgery (Current Controlled Trials in Cardiovascular Medicine 2005 Sep 7;6:14)

Glasgow Aneurysm Score predicts postoperative survival after open surgical or endovascular intervention

Glasgow Aneurysm Score (GAS) = age in years plus

7 points if myocardial disease (previous myocardial infarction and/or ongoing angina)

10 points if cerebrovascular disease (any stroke or transient ischemic attack)

14 points if renal disease (history of acute or chronic renal failure, creatinine level > 133 mcmol/L [1.51 mg/dL], and/or creatinine clearance < 50 mL/minute)

original GAS developed based on 500 randomly selected patients treated for AAA in general surgical units in Glasgow hospitals 1980-1990, and also included 17 points if shock (Cardiovasc Surg 1994 Feb;2(1):41)

GAS predicts postoperative mortality after endovascular AAA repair

prospective study of 5,498 patients (median age 73 years) with non-ruptured asymptomatic infrarenal AAA at least 4 cm (median 5.6 cm) who received endovascular self-expanding stent-graft and were followed at least 1 month, median GAS 78.8

155 patients (2.8%) died within 30 days

30-day mortality

1.1% with GAS < 74.4

2.1% with GAS 74.4-83.6

5.3% with GAS > 83.6

Reference - Br J Surg 2006 Feb;93(2):191 GAS appears to predict postoperative morbidity and mortality after elective open AAA repair

based on 3 retrospective studies

GAS predicted morbidity and mortality after elective open AAA repair

retrospective study of 1,911 patients undergoing open AAA repair with outcomes at 30 days

GAS > 76 (vs. < 76) predicted

mortality (9% vs. 3%)

severe complications (31% vs. 15%)

cardiac complications (12% vs. 4%)

intensive care unit stay > 5 days (12% vs. 6%)

Reference - Eur J Vasc Endovasc Surg 2003 Dec;26(6):612 GAS predicted postoperative death, severe postoperative complications, myocardial infarction, and stroke in retrospective study of 403 patients undergoing elective open repair of infrarenal AAA (Br J Surg 2003 Jul;90(7):838)

GAS, Leiden score, modified Leiden score and Vanzetto score each predicted in-hospital mortality in retrospective study of 286 patients undergoing elective infrarenal AAA repair; Eagle risk score less accurate for predicting in-hospital mortality; only modified Leiden score predicted postoperative complications (Eur J Vasc Endovasc Surg 2004 Jul;28(1):52)

poor preoperative lung and renal function are associated with postoperative mortality

based on prospective cohort study

cohort of 820 patients aged 60-80 years who had open surgery in UK Small Aneurysm Trial

5.6% overall postoperative mortality risk

postoperative mortality risk significantly associated with higher serum creatinine (p = 0.002) and lower forced expiratory volume in 1 second (p = 0.003)

postoperative mortality risk significantly associated with older age (p = 0.03, but p = 0.08 after adjusting for creatinine level and lower forced expiratory volume in 1 second)

Reference - Br J Surg 2000 Jun;87(6):742

Treatment

Treatment overview:

no good evidence to support medication as primary treatment to reduce AAA expansion or risk of AAA rupture

surgery

surgery recommended for AAA > 5.5 cm (grade B recommendation [inconsistent or limited evidence]) or symptomatic AAA of any diameter (grade C recommendation [lacking direct evidence])

surgery for AAA < 5.5 cm does not reduce mortality within 5 years (level 1 [likely reliable] evidence) but might improve survival after 5 years (level 2 [mid-level] evidence)

intervention not recommended for asymptomatic infrarenal or juxtrarenal AAA < 5 cm in men or < 4.5 cm in women (grade A recommendation [consistent high-quality evidence]) endovascular aneurysm repair (EVAR)

EVAR has lower perioperative mortality than open repair (level 1 [likely reliable] evidence) but similar all-cause mortality at 2-4 years (level 2 [mid-level] evidence)

EVAR may not improve all-cause mortality in patients unfit for open surgery (level 2 [mid-level] evidence) recommendations for ultrasound screening intervals based on aneurysm diameter vary

if > 4.5 cm, every 3-6 months

if 4-4.5 cm, every 6-12 months

if 3.5-4 cm, every 1-2 years

if < 3.5 cm, every 3 years

reduction of traditional cardiovascular risk factors recommended - see Cardiovascular disease prevention overview

Medications:

propranolol (Inderal) has insufficient evidence to support routine use

propranolol might reduce surgery rate but poorly tolerated (level 2 [mid-level] evidence)

based on randomized trial with non-significant trend

548 patients with asymptomatic AAA 3-5 cm randomized to propranolol (target dose 80-120 mg twice daily) vs. placebo for mean 2.5 years

AAA size measured every 6 months by ultrasound and surgery recommended if 5-5.5 cm

20% propranolol vs. 26% placebo patients had elective AAA surgery (p = 0.11)

38% vs. 21% withdrew due to adverse effects (NNH 4)

no significant difference in 12% vs. 9% overall mortality (p = 0.36)

Reference - J Vasc Surg 2002 Jan;35(1):72 in J Watch 2002 Mar 15;22(6):46

propranolol poorly tolerated and might increase mortality (level 2 [mid-level] evidence)

based on small randomized trial with high dropout rate

54 patients with small AAA diagnosed on screening were randomized to propranolol 40 mg vs. placebo PO twice daily

60% propranolol vs. 25% placebo patients dropped out, mainly due to dyspnea

16.7% propranolol vs. 4.2% placebo patients died (NNH 8)

Reference - Int Angiol 1999 Mar;18(1):52 beta blockers might reduce risk for AAA expansion and rupture (level 2 [mid-level] evidence)

based on retrospective studies

Reference - American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF ACE inhibitors reported to be associated with reduced risk of ruptured AAA (level 3 [lacking direct] evidence)

based on nested case-control study

retrospective study of 15,326 patients > 65 years old admitted to hospital for AAA

3,379 (22%) had ruptured AAA and 11,947 (78%) had intact AAA

ACE inhibitor use reported in 665 (20%) with ruptured AAA vs. 2,761 (23%) with intact AAA (odds ratio 0.82, 95% CI 0.74-0.9)

no statistically significant associations found for beta blockers, calcium channel blockers, alpha blockers, angiotensin receptor blockers or thiazide diuretics

Reference - Lancet 2006 Aug 19;368(9536):659, editorial can be found in Lancet 2006 Aug 19;368(9536):622, commentary can be found in Lancet 2006 Nov 4;368(9547):1571, Am Fam Physician 2006 Nov 15;74(10):1780

DynaMed commentary -- cohort of patients admitted to hospital with AAA may not best reflect cohort of patients with AAA

antichlamydial antibiotics may reduce AAA expansion rate but reduction in clinical outcomes (rupture, surgery) not established (level 3 [lacking direct] evidence)

based on 2 randomized trials too small to demonstrate clinical differences

doxycycline may reduce AAA expansion rate (level 3 [lacking direct] evidence)

based on small randomized trial without clinical outcomes

32 patients with AAA 3-5.5 cm randomized to doxycycline 150 mg vs. placebo daily for 3 months and followed for 18 months

41% doxycycline vs. 7% placebo patients had AAA expansion > 5 mm (NNT 3)

Reference - J Vasc Surg 2001 Oct;34(4):606

doxycycline brand names include Monodox, Vibramycin, Vibra-Tabs, Doryx

roxithromycin may reduce AAA expansion rate but may not affect clinical outcomes (level 3 [lacking direct] evidence)

based on small randomized trial

92 men with AAA 3-4.9 cm diameter were randomized to roxithromycin 300 mg vs. placebo PO once daily for 28 days

AAA size monitored annually by ultrasound, men with AAA > 5 cm referred for surgery


comparing roxithromycin vs. placebo

mean AAA expansion rate 1.56 vs. 2.75 mm/year (p = 0.02)

33% vs. 47% had AAA expansion rate > 2 mm/year (not significant in crude analysis, statistically significant in logistic regression analysis)

12% vs. 14% referred for surgery (not significant)

Reference - Br J Surg 2001 Aug;88(8):1066, Ugeskr Laeger 2002 Dec 9;164(50):5916

roxithromycin brand names include Surlid, Rulide, Biaxsig, Roxar, Roximycin

Surgery:

Patient selection:

potential indications for AAA repair

ruptured AAA

symptomatic AAA

rapidly expanding aneurysm

asymptomatic aneurysms > 5.5 cm

complicated aneurysms

relative contraindications to AAA repair

short life expectancy

myocardial infarction within 6 months

intractable heart failure

severe angina

severe renal dysfunction

decreased mental acuity

surgery recommended for AAA 5.5 cm or larger to eliminate risk of rupture (grade B recommendation [inconsistent or limited evidence])

based on observational evidence

surgery recommended for infrarenal or juxtarenal AAA 5.5 cm or larger to eliminate risk of rupture (grade B recommendation [inconsistent or limited evidence])

surgery probably indicated for suprarenal or type IV thoracoabdominal aneurysms > 5.5 cm (grade B recommendation [inconsistent or limited evidence])

Reference - American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF surgery for AAA < 5.5 cm does not reduce mortality within 5 years (level 1 [likely reliable] evidence) but might improve survival after 5 years (level 2 [mid-level] evidence)

based on 2 randomized trials with 2,226 patients

surgery does not improve 5-year survival for AAA < 5.5 cm (level 1 [likely reliable] evidence)

based on randomized trial

1,136 patients 50-79 years old with asymptomatic AAA 4-5.4 cm diameter who did not have high surgical risk were randomized to immediate open surgical repair vs. surveillance

surveillance group had ultrasound or CT every 6 months with repair for symptomatic aneurysms or aneurysms > 5.5 cm

mean follow-up 4.9 years (range 3.5-8 years)

comparing surgery vs. surveillance

92.6% vs. 61.6% had aneurysm repair by end of study

25.1% vs. 21.5% overall mortality (not significant)

3% vs. 2.6% death related to AAA (not significant)

0.4 vs. 1.9% rupture of AAA (7 of 11 ruptures in surveillance group resulted in death), rate of AAA rupture was 0.6%/year in surveillance group

survival trends did not favor surgery in any prespecified subgroup

Reference - ADAM trial (N Engl J Med 2002 May 9;346(19):1437), editorial can be found in N Engl J Med 2002 May 9;346(19):1484, commentary can be found in POEMs in J Fam Pract 2002 Aug;51(8):671, N Engl J Med 2002 Oct 3;347(14):1112 (correction can be found in N Engl J Med 2002 Dec 5;347(23):1902)

immediate repair vs. surveillance had no significant differences in most quality of life measures

surgery group had increased rate of impotence after 1 year (p < 0.03)

surgery group had better general health scores (p < 0.0001), particularly in first 2 years after randomization

no significant differences in other quality of life measures

Reference - J Vasc Surg 2003 Oct;38(4):745 surgery of small AAA (4-5.5 cm) associated with short-term mortality risk and small long-term survival benefit at 6-10 years (level 2 [mid-level] evidence)

based on randomized trial with borderline statistical significance

1,090 patients ages 60-76 years with AAA 4-5.4 cm diameter were randomized to early elective surgery vs. surveillance by ultrasound (with repair for symptomatic aneurysms or aneurysms > 5.5 cm or expanding > 1 cm/year)

mean follow-up 8 years (range 6-10 years)

comparing surgery vs. surveillance

5.5% 30-day mortality led to early disadvantage with surgery

survival equivalent at 2, 3, 4 and 6 years

28.2% vs. 28.5% mortality at 6 years

43% vs. 48.2% mortality at end of study (p = 0.05, NNT 20)

restricted mean duration of survival at 9 years was 6.5 vs. 6.7 years (not significant)

92.4% vs. 62% had aneurysm repair by end of study

benefit in early surgery group may be associated with lifestyle changes, especially smoking cessation which was 12.8 times more likely after aneurysm repair

no overall differences in quality of life at 1 year but early surgery group had positive improvement in current health perceptions and less negative change in bodily pain

References - UK Small Aneurysm Trial

N Engl J Med 2002 May 9;346(19):1445, editorial can be found in N Engl J Med 2002 May 9;346(19):1484, summary can be found in Am Fam Physician 2002 Sep 15;66(6):1086, commentary can be found in N Engl J Med 2002 Oct 3;347(14):1112, N Engl J Med 2005 Sep 15;353(11):1181

Lancet 1998 Nov 21;352(9141):1649, 1656, commentary can be found in Lancet 1999 Jan 30;353(9150):407 61% surveillance group eventually had surgery (Evidence-Based Medicine 1999 May/Jun;4(3):88)

Cochrane review on surgery for small AAAs not updated since 1999; systematic review last updated 1999 May 5 (Cochrane Library 1999 Issue 4:CD001835)

surgery recommended for symptomatic AAA of any diameter (grade C recommendation [lacking direct evidence])

based on case series, consensus opinion or standard of care

Reference - American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF intervention not recommended for asymptomatic infrarenal or juxtarenal AAA < 5 cm in men or < 4.5 cm in women (grade A recommendation [consistent high-quality evidence])

based on data derived from multiple randomized trials or meta-analyses

American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDFPerioperative management:

perioperative cardiac management

multiple methods for risk stratification include Eagle's 5-point scale, Revised Cardiac Risk Index, and stress imaging

perioperative maintenance of normothermia reduces rate of postoperative unstable angina (level 1 [likely reliable] evidence) based on randomized trial

regional anesthesia may not be associated with lower cardiovascular risk than general anesthesia in patients having vascular surgery (level 2 [mid-level] evidence) based on 4 randomized trials

perioperative beta blockers may reduce mortality and myocardial infarction risk (level 2 [mid-level] evidence) based mostly on small randomized trials

perioperative metoprolol may be ineffective or less effective than atenolol or bisoprolol (level 2 [mid-level] evidence) perioperative clonidine for 4 days associated with reduced mortality for up to 2 years (level 1 [likely reliable] evidence), based on 1 randomized trial, despite no statistically significant effect on myocardial infarction (level 2 [mid-level] evidence), based on 8 randomized trials

statins might be associated with lower perioperative cardiovascular risk (level 2 [mid-level] evidence) based on randomized trial and systematic review of observational evidence

coronary artery revascularization before major vascular surgery did not affect long-term mortality (level 2 [mid-level] evidence) in 1 randomized trial

preoperative cardiac stress testing for intermediate-risk patients not associated with surgical risk reduction (level 2 [mid-level] evidence) in 1 randomized trial

see Perioperative cardiac management for noncardiac surgery for details

antimicrobial prophylaxis recommended just before surgery with cefazolin (Ancef) 1-2 g IV

alternative for hospitals with frequent methicillin-resistant postoperative wound infections or allergy to cephalosporins is vancomycin (Vancocin) 1 g IV given very slowly to avoid hypotension, diphenhydramine (Benadryl) may also be helpful to avoid hypotension

Reference - Med Lett Drugs Ther 2001 Oct 29;43(1116-1117):92 autologous blood (autotransfusion) might not reduce hospital stay or rate of complications (level 2 [mid-level] evidence)

based on 4 small randomized trials with inconsistent results

autologous transfusion and allogeneic transfusion had no significant differences in hospital stay or rate of complications in randomized trial of 145 patients (Ann Surg 2002 Jan;235(1):145 full-text)

intraoperative autotransfusion did not appear to reduce rate of complications in randomized trial of 100 patients (J Vasc Surg 1999 Jan;29(1):22)

intraoperative autotransfusion (vs. homologous blood transfusion) associated with reduced incidence of postoperative systemic inflammatory response syndrome (23% vs. 49%, p = 0.02, NNT 4) and chest infection (10% vs. 29%, p = 0.049, NNT 6) in randomized trial of 81 patients (Br J Surg 2004 Nov;91(11):1443)

autologous transfusion appeared to reduce length of hospital stay (median 9 vs. 12 days, p < 0.05) in randomized trial of 50 patients (Eur J Vasc Endovasc Surg 1997 Dec;14(6):482, J Vasc Nurs 1997 Dec;15(4):111)

N-acetylcysteine did not significantly protect against renal injury (level 3 [lacking direct] evidence) in randomized placebo-controlled trial of 70 patients with normal preoperative renal function who had abdominal aortic surgery (Anesth Analg 2006 Jun;102(6):1638)

type of fluid used not shown to affect outcomes

based on Cochrane review of 9 trials with 412 patients undergoing abdominal aortic surgery

Reference - systematic review last updated 2000 May 15 (Cochrane Library 2000 Issue 4:CD000991)

pulmonary artery catheterization does NOT improve outcomes in high-risk surgery


1,994 high-risk patients > 60 years old scheduled for urgent or elective major surgery were randomized to pulmonary-artery catheter vs. no pulmonary-artery catheter

no differences in overall survival in hospital or at 1-year follow-up

pulmonary-artery catheter use associated with higher rate of pulmonary embolism (8 vs. 0 events, NNH 124)

Reference - N Engl J Med 2003 Jan 2;348(1):5, editorial can be found in N Engl J Med 2003 Jan 2;348(1):66, summary can be found in Am Fam Physician 2003 Apr 15;67(8):1787, commentary can be found in N Engl J Med 2003 May 15;348(20):2035, ACP J Club 2003 Nov-Dec;139(3):66 aortic clamp considerations

minimize aortic clamp time

remove clamp slowly, adjust fluid status

complications of clamp removal - acidosis, hyperkalemia

epidural analgesia provides better pain relief and lower complication rate than systemic opioid-based analgesia after open abdominal aortic surgery (level 1 [likely reliable] evidence)

systematic review of 13 randomized trials comparing epidural analgesia and postoperative systemic opioid-based analgesia in 1,224 adults who had elective open abdominal aortic surgery

adequate allocation concealment used in 6 trials

study assessors blinded in 3 trials

intention-to-treat analysis performed in 7 trials

insufficient evidence to confirm or exclude differences in postoperative mortality (3.6% vs. 4.4%, not statistically significant) based on 11 trials with 1,210 patients

epidural analgesia associated with lower visual analog scale scores for pain

at rest on day 1 (statistically significant) and day 2 (not statistically significant)

on movement at postoperative days 1, 2 and 3 (statistically significant)

epidural analgesia associated with about 20% reduction in duration of tracheal intubation or mechanical ventilation

epidural analgesia associated with significantly lower rates of

overall incidence of cardiovascular complication (21.2% vs. 27.9%, p = 0.03, NNT 15) in 4 trials with 611 patients, but difference no longer significant in meta-analysis using random effects model

myocardial infarction (3.8% vs. 7.5%, p = 0.03, NNT 27) in 7 trials with 851 patients

acute respiratory failure (19.8% vs. 30.7%, p = 0.00004, NNT 10) in 6 trials with 861 patients

gastrointestinal complications (1.2% vs. 3.5%, p = 0.03, NNT 50) in 5 trials with 802 patients

renal insufficiency (12.2% vs. 18.9%, p = 0.01, NNT 15) in 5 trials with 738 patients

Reference - systematic review last updated 2006 May 17 (Cochrane Library 2006 Issue 3:CD005059)

Surgical approaches:

direct synthetic graft replacement of infrarenal AAA is standard of care

alternatives

percutaneous transfemoral placement of intraaortic graft (endovascular stent-graft )

extra-anatomic bypass with aneurysm thrombosis or exclusion (aneurysmectomy)

retroperitoneal incision may be associated fewer complications than transabdominal incision, but evidence inconsistent (level 2 [mid-level] evidence)

based on 3 randomized trials

retroperitoneal incision associated with reduced ICU stay and fewer complications in trial in 145 patients having vascular surgery

145 patients having surgery for AAA (81 patients) or aortoiliac occlusive disease (64 patients) were randomized to retroperitoneal vs. transabdominal incision

retroperitoneal incision associated with statistically significant reductions in

prolonged ileus

small bowel obstruction

overall complications

intensive care unit stay (2.3 vs. 3.5 days)

Reference - J Vasc Surg 1995 Feb;21(2):174 retroperitoneal approach not superior in trial in 100 patients having vascular surgery

100 patients having surgery for AAA (64 patients) or aortoiliac occlusive disease (36 patients) were randomized to retroperitoneal vs. transabdominal incision

no significant differences in mortality, morbidity, length of ICU stay (2 vs. 2 days), or length of hospital stay

retroperitoneal approach associated with significantly more wound problems (bulging, hernias and wound pain)

Reference - Cardiovasc Surg 1997 Feb;5(1):71 retroperitoneal approach associated with reduced hospital stay in trial in 36 patients having AAA repair

36 patients having AAA repair randomized to retroperitoneal vs. transabdominal surgery

comparing retroperitoneal vs. transabdominal surgery

mean time to ambulation 2.6 vs. 4.3 (p = 0.005)

mean duration of hospital stay 10.2 vs. 14.5 days (p < 0.0001)

Reference - J Med Assoc Thai 2005 May;88(5):601 minimal incision aortic surgery associated with shorter hospital stay than conventional transperitoneal surgery (level 2 [mid-level] evidence)

based on 2 small randomized trials

minimal incision aortic surgery also called mini-laparotomy or minimally invasive vascular surgery

72 patients with nonruptured AAA randomized to minimal incision aortic surgery vs. retroperitoneal approach vs. transperitoneal approach

transperitoneal approach associated with longer length of ICU stay and hospital stay than other 2 approaches

Reference - Int Angiol 2005 Sep;24(3):238 34 patients with AAA randomized to minimally invasive vascular surgery vs. conventional open repair

mean time to ambulation 2.1 vs. 4.3 days (p < 0.01)

mean duration of hospital stay 20.7 vs. 33.9 days (p < 0.01)

Reference - J Vasc Surg 2002 Apr;35(4):654Surgical complications:

lower annual hospital volume of AAA repair associated with higher mortality (level 2 [mid-level] evidence)

based on meta-analysis of observational studies

in analysis of 21 studies plus UK Hospital Episode Statistics data with 421,299 elective AAA repairs

9.5% overall mortality rate

annual volume < 43 repairs associated with significantly higher mortality

in analysis of 12 studies plus UK data with 45,796 ruptured AAA repairs

37% overall mortality rate

annual volume < 15 repairs associated with significantly higher mortality

Reference - Br J Surg 2007 Apr;94(4):395 mortality rates for elective AAA < 5% with experience (level 2 [mid-level] evidence)

based on observational study

study of all 2,335 elective open surgical AAA repairs done at all non-federal hospitals in Maryland from 1990-1995

3.5% overall in-hospital mortality rate

mortality increased with age from 2.2% < 65 years to 7.3% > 80 years

mortality 2.5% at hospitals with > 100 operations over the 6 years and 4.2-4.3% at hospitals with lower volumes

mortality 9.9% if surgeons performed only 1 elective AAA repair over the 6 years, 4.9% if 2-9 procedures, 2.8-3.8% if higher volumes

age, hospital volume and surgeon volume were significant predictors for perioperative mortality

Reference - J Vasc Surg 1999 Dec;30(6):985 post-operative renal failure (21% rupture, 2.5% elective), mortality up to 90%

ischemic colitis in 9-16%

suspect if postoperative diarrhea, especially heme-positive

treatment is Hartmann's procedure

replanting inferior mesenteric artery instead of ligating inferior mesenteric artery not associated with statistically significant reduction in risk of ischemic colitis (level 2 [mid-level] evidence) (9% vs. 16%) in randomized trial in 128 patients with patent inferior mesenteric artery having infrarenal aortic aneurysm repair (J Vasc Surg 2006 Apr;43(4):689)

acute leg ischemia in up to 7%, related to clamp injury or emboli

aortic graft infection in 1-4%

bacterial seeding or bacteremia, #1 S. aureus, S. epidermidis

pseudointima has decreased resistance to infection

perioperatively first generation cephalosporin

may present as inflammatory mass or draining sinus in groin, fever, occasionally abdominal discomfort, multiple petechiae distally, aortoenteric fistula

CT, indium-tagged WBC, aortogram, sinogram outlines graft if draining sinus

CT to rule out splenic abscess before replacing vascular graft

prophylactic antibiotics recommended for invasive procedures in patients with aortic graft (similar to patients with valvular heart disease)

spinal cord ischemia rare 0.25%, especially if ruptured

injury to artery of Adamkiewicz left T8-L1 occasionally to L4

classic anterior spinal syndrome - paraplegia, rectal/urinary incontinence, loss of pain/temperature sensations, retention of vibration/proprioception sensations

aortoenteric fistula - any patient with GI bleeding and prosthetic vasc graft in abdomen, esophagogastroduodenoscopy to view distal duodenum

pseudoaneurysm (dilation with disruption of layers of vascular wall)

retrograde ejaculation if sympathetic nerves injured

impotence if no perfusion in hypogastric arteries

Endovascular stent-graft:

FDA recommends using AneuRx Stent Graft only in patients meeting appropriate risk-benefit profile who can be treated according to instructions, based on 1.5% perioperative mortality in analysis of 942 patients (FDA MedWatch 2003 Dec 17)

endovascular aneurysm repair (EVAR) has lower perioperative mortality than open repair (level 1 [likely reliable] evidence) but similar all-cause mortality at 2-4 years (level 2 [mid-level] evidence)

based on 4 randomized trials with ascertainment bias for long-term outcomes

systematic review of 4 randomized trials comparing endovascular repair vs. open repair in 1,532 patients with large AAAs

endovascular repair had lower 30-day mortality (1.6% vs. 4.8%, NNT 32)

endovascular repair had shorter hospital stay (weighted median 6.2 vs. 11.5 days)

outcomes at 2-4 years limited by not attributing deaths to AAA if autopsy not done

comparing endovascular vs. open repair at 2-4 years in 3 trials with 1,473 patients

3% vs. 5.7% AAA-related mortality (p = 0.02, NNT 37)

16.8% vs. 17.6% all-cause mortality (not significant, 95% CI ranges from NNT 24 to NNH 30)

Reference - Ann Intern Med 2007 May 15;146(10):735, editorial can be found in Ann Intern Med 2007 May 15;146(10):749, commentary can be found in Ann Intern Med 2008 Feb 5;148(3):245 systematic review of 2 randomized trials comparing endovascular repair vs. open surgical repair for AAA at least 5.5 cm with follow-up at least 2 years

endovascular repair had lower 30-day mortality (1.6% vs. 4.7%, NNT 33)

endovascular repair had higher rates of postoperative complications and reinterventions

no significant differences in mortality at 2 years or quality of life after 3-6 months

Reference - AHRQ Evidence Report on Abdominal Aortic Aneurysm, Endovascular and Open Surgical Repairs 2006 Aug:144 EVAR trial 1

1,082 patients > 60 years old with AAA at least 5.5 cm randomized to endovascular vs. open AAA repair

1,017 patients (94%) complied with allocated treatment

comparing endovascular vs. open AAA repair at 30 days

1.7% vs. 4.7% mortality (p = 0.009, NNT 34)

9.8% vs. 5.8% rate of secondary interventions (p = 0.02, NNH 25)

Reference - EVAR 1 trial (Lancet 2004 Sep 4;364(9437):843), editorial can be found in Lancet 2004 Sep 4-10;364(9437):818; commentary can be found in Am Fam Physician 2005 Jun 15;71(12):2368

EVAR and open aneurysm repair appear to have similar all-cause mortality at 4 years (level 2 [mid-level] evidence)

follow-up rates were 100% at 1 year, 70% at 2 years, 47% at 3 years and 24% at 4 years

comparing endovascular vs. open AAA repair at 4 years in intent-to-treat analysis (all 1,082 patients)

18.4% vs. 20.2% deaths from any cause (not statistically significant)

3.5% vs. 6.3% aneurysm-related deaths (p = 0.04, NNT 36)

41% vs. 9% postoperative complications (p < 0.0001, NNH 3)

no difference in quality of life after 12 months

Reference - Lancet 2005 Jun 25;365(9478):2179, editorial can be found in Lancet 2005 Jun 25;365(9478):2156, commentary can be found in Lancet 2005 Sep 10;366(9489):890, 890, BMJ 2005 Sep 24;331(7518):644, BMJ 2005 Nov 5;331(7524):1081, Perspect Vasc Surg Endovasc Ther 2006 Mar;18(1):74 DREAM trial

based on randomized trial with inadequate statistical power for mortality outcome

endovascular repair has lower perioperative complication rate than open repair (level 1 [likely reliable] evidence) and possibly lower perioperative mortality (level 2 [mid-level] evidence)


351 patients (mean age 70 years) with AAA at least 5 cm randomized to endovascular vs. open AAA repair

6 patients who did not undergo surgery were excluded

comparing endovascular vs. open AAA repair at 30 days

1.2% vs. 4.6% mortality (NNT 30 but not statistically significant, p = 0.1)

4.7% vs. 9.8% combined rate of operative mortality and severe complications (NNH 20 but not statistically significant, p = 0.1)

3.5% vs. 10.9% severe complications (p = 0.01, NNT 14)

2.9% vs. 10.9% pulmonary complications (p = 0.005, NNT 13)

Reference - DREAM trial (N Engl J Med 2004 Oct 14;351(16):1607), editorial can be found in N Engl J Med 2004 Oct 14;351(16):1677 2-year survival rates 89.7% vs. 89.6%

differences in first year based entirely on first 30 days

only 1 aneurysm-related death in each group after hospital discharge

no significant differences in rates of moderate or severe complications

Reference - N Engl J Med 2005 Jun 9;352(23):2398, editorial can be found in N Engl J Med 2005 Jun 9;352(23):2443, commentary can be found in ACP J Club 2005 Nov-Dec;143(3):64 3-year outcomes with endovascular repair in clinical practice similar to DREAM trial

856 patients who had EVAR in prospective EUROSTAR registry compared to 177 patients who had EVAR in DREAM trial

no significant differences at 3 years in survival (86.8% vs. 87.6%) or freedom of secondary procedures (86.9% vs. 85.7%)

Reference - Eur J Vasc Endovasc Surg 2007 Feb;33(2):172 EVAR may not improve all-cause mortality in patients unfit for open surgery (level 2 [mid-level] evidence)

based on randomized trial with high crossover rate

338 patients > 60 years old with aneurysms at least 5.5 cm diameter referred to 31 UK hospitals and considered unfit for major surgery were randomized to EVAR vs. no intervention

aneurysm repair done in 150 of 166 patients assigned to EVAR and 47 of 172 assigned to no intervention (thus reducing apparent benefit of EVAR)


EVAR group had 30-day mortality of 9% (NNH 11)

control group had rupture rate of 9 per 100 person-years

no significant differences in all-cause mortality (64%), aneurysm-related mortality or quality of life at 4 years

9 of 20 aneurysm-related deaths in EVAR group occurred before EVAR was done (reducing apparent benefit of EVAR)

Reference - EVAR 2 trial (Lancet 2005 Jun 25;365(9478):2187), editorial can be found in Lancet 2005 Jun 25-Jul 1;365(9478):2156, commentary can be found in Lancet 2005 Sep 10;366(9489):890, 890, Perspect Vasc Surg Endovasc Ther 2006 Mar;18(1):76 endovascular repair associated with lower morbidity and mortality than open repair in many observational studies (level 2 [mid-level] evidence)

matched cohort study of Medicare beneficiaries

22,830 patients (mean age 76 years) who had endovascular repair compared with 22,830 patients who had open AAA repair in US in 2001-2004

comparing endovascular vs. open repair

1.2% vs. 4.8% perioperative mortality (p < 0.001)

0.4% vs. 2.5% perioperative mortality in those aged 67-69 years (p < 0.001)

2.7% vs. 11.2% for those 85 years old (p < 0.001)

1.8% vs. 0.5% rupture within 4 years (p < 0.001)

9.7%, vs. 4.1% surgery for laparotomy-related complications within 4 years (p < 0.001)

9% vs. 1.7% reintervention related to AAA within 4 years (p < 0.001) (most reinterventions were minor)

14.2% vs. 8.1% hospitalization without surgery for bowel obstruction or abdominal-wall hernia within 4 years (p < 0.001)

mean hospital stay 3.4 vs. 9.3 days (p < 0.001)

medical complications significantly less likely with endovascular repair included myocardial infarction, pneumonia, acute renal failure, deep vein thrombosis or pulmonary embolism (p < 0.001)

Reference - N Engl J Med 2008 Jan 31;358(5):464 retrospective review

comparing 2,565 patients who had endovascular repair vs. 4,607 patients who had open AAA repair in US in 2001

1.3% vs. 3.8% hospital mortality (p = 0.0001)

18% vs. 29% any complications (p = 0.0001)

median hospital stay 2 vs. 7 days (p = 0.0001)

outcomes not tracked after hospital discharge; outcomes still significant after adjustment for risk factors

Reference - J Vasc 2004 Mar;39(3):491 retrospective review comparing 94 endovascular vs. 261 open repairs at Mayo Clinic 1999-2001 at 30 days

0 vs. 1.1% mortality (not significant)

11% vs. 22% cardiac complications (p = 0.02)

3% vs. 16% pulmonary complications (p = 0.001)

13% vs. 4% graft-related complications (p = 0.002)

Reference - J Vasc 2004 Mar;39(3):497 fewer complications (but similar mortality) in 260 patients having endoluminal graft repair compared to 201 patients having conventional open repair (Ann Surg 2001 Oct;234(4):427 in BMJ 2001 Nov 24;323(7323):1260)

non-randomized industry-sponsored multicenter study

190 patients with infrarenal AAA who had AneuRx stent-graft compared with 60 controls who had open surgical repair

major differences favoring stent-graft

shorter (3 vs. 9 days) mean length of hospital stay

reduced transfusion requirement

reduced 30-day rate (12% vs. 23%) of complications

problems with stent-graft were technical inability to access in 4 patients, 21% internal leaks (most spontaneously sealed by 6 months), migration in 3 patients

no stent-graft patient had ruptured AAA or conversion to open surgery in 1 year of follow-up

Reference - J Vasc Surg 1999 Feb;29(2):292 outcomes in series of patients who had endovascular AAA repair

Click for Details endovascular repair associated with high incidence of late secondary interventions; 18% rate of secondary interventions occurring mean 14 months after initial endograft procedure in study of 1,023 patients followed at least 12 months from the EUROSTAR registry (Br J Surg 2000 Dec;87(12):1666 in JAMA 2001 Apr 4;285(13):1683)

in series of 873 patients followed mean 27 months after EVAR

1.8% mortality at 30 days

estimated freedom from AAA rupture 97.6% at 5 years and 94% at 9 years

risk factors for late AAA rupture were female gender and device-related endoleak

87 (10%) patients had reintervention

cumulative survival 52% at 5 years

Reference - Ann Surg 2006 Sep;244(3):426 in series of 150 patients older than 80 years followed for mean 17 months after endovascular AAA repair, 3.3% perioperative mortality, 15% required additional graft-related interventions (Arch Surg 2004 Mar;139(3):308 in J Watch Online 2004 Apr 2)

mean 16 month follow-up of 239 endovascular graft repairs for nonruptured AAAs, 8.5% 30-day mortality but reduced over time (13.6% prior to 1999, 4.4% after 1999), 36% actuarial 5-year survival but most deaths unrelated to AAAs, 23 patients required secondary procedures (Ann Surg 2001 Sep;234(3):323 in J Watch 2001 Oct 15;21(20):161)

first generation stent grafts associated with high risk of late complications

based on cohort of 1,190 patients in EUROSTAR registry who had endovascular stent-graft with Stentor or Vanguard graft and were followed for up to 8 years

7.1% conversion to open repair

2.4% aneurysm rupture

19.9% all-cause mortality

3% aneurysm-related mortality

48% survival at 8 years free of these events

frequent procedure-related complications were endoleak (13 per 100 patient-years), stenosis/thrombosis (4.6 per 100 patient-years) and stent migration (4.3 per 100 patient-years)

Reference - Arch Surg 2007 Jan;142(1):33 retrospective report of first 100 patients treated with endovascular repair at Mayo Clinic can be found in Mayo Clin Proc 2003 Oct;78(10):1234 full-text, commentary can be found in Mayo Clin Proc 2004 Apr;79(4):570 PDF endovascular repair associated with shorter hospitalization (level 2 [mid-level] evidence)

based on small randomized trial

40 patients with low surgical risk profile randomized to endovascular vs. open repair

mean duration of hospitalization 4.5 vs. 11.5 days (p = 0.001)

no significant differences in functional autonomy and quality of life measures

Reference - J Vasc Interv Radiol 2005 Aug;16(8):1093 insufficient evidence to recommend emergency endovascular repair for ruptured AAA

based on Cochrane review

systematic review of randomized trials comparing emergency EVAR vs. open surgical repair in patients with confirmed ruptured AAA

no randomized trials identified

Reference - systematic review last updated 2006 Nov 1 (Cochrane Library 2007 Issue 1:CD005261)

emergency EVAR and open repair appear to have similar outcomes in patients with ruptured AAA (level 2 [mid-level] evidence)

based on observational study of 100 patients with ruptured AAA

49 patients treated with emergency EVAR compared to 51 patients treated with open surgery

comparing emergency EVAR vs. open repair

35% vs. 39% in-hospital or 30-day mortality (not statistically significant)

40% vs. 42% all-cause mortality at 3 months (not statistically significantly)

59% primary complication rate in both groups at 3 months

Reference - J Vasc Surg 2006 Jun;43(6):1111 review of endovascular repair of AAA can be found in N Engl J Med 2008 Jan 31;358(5):494

review of endovascular repair of AAA can be found in Mayo Clin Proc 1999 Oct;74(10):999

discussion of endovascular repair with stent graft can be found in Postgrad Med 2001 Jun;109(6):93

National Institute for Health and Clinical Excellence (NICE) guidance on stent-graft placement in abdominal aortic aneurysm can be found in NICE 2006 Mar:IPG163

Canadian Society for Vascular Surgery consensus statement on endovascular aneurysm repair can be found in CMAJ 2005 Mar 29;172(7):867Follow-up:

small aneurysms (4-5.5 cm) should be followed conservatively

recommendations for ultrasound (or CT) screening intervals based on aneurysm diameter vary

recommended follow-up (ultrasound or CT scan) for infrarenal or juxtarenal AAA

if 4-5.4 cm, every 6-12 months

if < 4 cm, every 2-3 years

American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF recommended ultrasound screening intervals based on aneurysm diameter

if > 4.5 cm, every 3 months

if 4.01-4.5 cm, every 12 months

if 3.51-4 cm, every 2 years

if < 3.5 cm, every 3 years

based on limits to restrict probability of breaching 55-mm limit at rescreening to < 1%

based on cohort of 1,743 patients monitored by ultrasound every 3-6 months for changes in AAA diameter for mean follow-up 1.9 years, patients were enrolled in surveillance arm of trial assessing immediate surgery vs. surveillance, mean initial AAA diameter 4.3 cm (range 2.8-8.5 cm) and mean growth rate 2.6 mm/year

strongest predictor of growth rate was baseline diameter, suggesting AAA growth accelerates as aneurysm enlarges

Reference - Circulation 2004 Jul 6;110(1):16 recommended ultrasound screening intervals based on aneurysm diameter

if 3.5-3.9 cm, rescan at 1 year

if 3-3.4 cm, rescan at 3 years

if 2.6-2.9 cm, rescan at 5 years

based on observational study of 1,121 men > 65 years old followed over 12 years

among 625 men with AAA 2.6-2.9 cm, 2.4% exceeded 5.5 cm or required surgery within 5 years, no ruptures

among 330 men with AAA 3-3.4 cm, 2.1% reached 5.5 cm and 2.9% required surgery at 3 years, no ruptures at 3 years

among 166 men with AAA 3.5-3.9 cm, 1.2% exceeded 5.5 cm at 1 year with no ruptures; at 2 years, 10.5% exceeded 5.5 cm and 1.4% ruptured

Reference - Br J Surg 2003 Jul;90(7):821 in JAMA 2003 Sep 10;290(10):1289

long-term surveillance imaging after endovascular repair

recommended to

monitor for endoleak

document shrinkage or stability of excluded aneurysm sac

determine need for further intervention

ultrasound may not be as sensitive as CT angiography for detection of endoleak after endovascular repair (level 2 [mid-level] evidence)

based on 2 cohort studies with inconsistent results

high quality duplex ultrasound scanning comparable to CT angiography in follow-up imaging in 100 consecutive AAA endovascular surgery patients (J Vasc Surg 2000 Dec;32(6):1142)

ultrasound scanning with or without contrast enhancement not as reliable as CT in diagnosing type II endoleak in cohort of 53 patients who had endovascular AAA repair (J Endovasc Ther 2002 Apr;9(2):170)

Prevention and Screening

Screening:

US Preventive Services Task Force recommendations

USPSTF recommends one-time screening for AAA by ultrasonography in men aged 65-75 years who have ever smoked (B recommendation)

USPSTF makes no recommendation for or against screening for AAA in men aged 65-75 years who have never smoked (C recommendation)

USPSTF recommends against routine screening for AAA in women (D recommendation)

Reference - Ann Intern Med 2005 Feb 1;142(3):198, supporting systematic review can be found in Ann Intern Med 2005 Feb 1;142(3):203, summary can be found at National Guideline Clearinghouse 2005 Feb 7:6013 or in Am Fam Physician 2005 Jun 1;71(11):2144, commentary can be found in J Fam Pract 2005 May;54(5):408, ACP J Club 2005 Jul-Aug;143(1):11, Ann Intern Med 2005 Aug 16;143(4):309 ACC/AHA recommends screening for

men > 60 years old with first-degree relatives with AAA (grade B recommendation [inconsistent or limited evidence])

men ages 65-75 years who have ever smoked (grade B recommendation [inconsistent or limited evidence])

Reference - American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) can be found in J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF Medicare will pay for AAA ultrasound screening for men ages 65-75 years who have smoked at least 100 cigarettes in their lifetime, and for persons with family history of AAAs (AAFP News Now 2006 Nov 8, Medicare News Release 2006 Nov 1), commentary can be found in Fam Pract Manag 2007 Apr;14(4):16

screening men > 65 years old reduces AAA mortality (level 1 [likely reliable] evidence)

based on 4 randomized trials

ultrasound screening reduces AAA mortality in men aged 65-79 years (level 1 [likely reliable] evidence)

based on Cochrane review

systematic review of 4 randomized trials comparing screening vs. no screening in 127,891 men and 9,342 women (only 1 trial included women)

comparing screening vs. no screening in men (meta-analysis of 3 trials with 112,937 men)

11.6% vs. 12.3% all-cause mortality in men (not significant), limited by heterogeneity (p = 0.004)

0.16% vs. 0.27% death from AAA (p = 0.0001, NNT 909)

comparing screening vs. no screening in women (1 trial with 9,342 women)

10.7% vs. 10.2% all-cause mortality in women (not significant)

0.085% vs. 0.043% death from AAA (not significant)

other outcomes comparing screening vs. no screening

0.28% vs. 0.62% ruptured AAA (p = 0.05, NNT 295) in 1 trial with 6,433 men

0.064% vs. 0.043% ruptured AAA (not significant) in 1 trial with 9,342 women

0.89% vs. 0.42% surgery for AAA (p < 0.00001, NNH 212) in 4 trials with 125,595 persons

Reference - systematic review last updated 2007 Jan 26 (Cochrane Library 2007 Issue 2:CD002945), editorial commentary can be found in BMJ 2007 Oct 13;335(7623):732, commentary can be found in BMJ 2007 Nov 3;335(7626):899 ultrasound screening is effective and marginally cost-effective in reducing AAA-related mortality (level 1 [likely reliable] evidence)


67,800 men age 65-74 years were randomized to be invited vs. not invited for ultrasound screening

men with abdominal aortic aneurysms 3 cm in diameter or greater were followed with repeat ultrasounds for mean 4.1 years

surgery considered if diameter 5.5 cm or greater, expansion 1 cm per year or greater, or symptoms

27,147 of 33,839 (80%) men invited for screening had ultrasound, 1,333 aneurysms (4.9%) were detected

99% followed up for mortality

comparing invited vs. control group

11.1% vs. 11.4% all-cause mortality (not significant)

0.19% (65 cases) vs. 0.33% (113 cases) aneurysm-related mortality (p = 0.0002, NNT 714)

0.24% (82 cases) vs. 0.41% (140 cases) ruptured AAA (fatal or non-fatal) (NNT 589)

30-day mortality was 6% after elective surgery (24 of 414) and 37% (30 of 81) after emergency surgery

Reference - Multicentre Aneurysm Screening Study (MASS) (Lancet 2002 Nov 16;360(9345):1531), commentary can be found in Lancet 2003 Mar 22;361(9362):1056, POEMs in J Fam Pract 2003 Apr;52(4):272, ACP J Club 2003 May-Jun;138(3):66

ultrasound screening was at margin of acceptability for cost-effectiveness at 4 years, but projected to be more cost-effective at 10 years (BMJ 2002 Nov 16;325(7373):1135), editorial can be found in BMJ 2002 Nov 16;325(7373):1123, commentary can be found in BMJ 2003 Feb 1;326(7383):284, ACP J Club 2003 Jul-Aug;139(1):24

early reduction in AAA-related mortality maintained at 7 years (level 1 [likely reliable] evidence)

based on mean follow-up 7.1 years (range 5.9-8.2 years) of MASS trial

of 67,770 men randomized, 66,328 (97.9%) had follow-up for mortality

comparing invited vs. control group

0.31% (105 cases) vs. 0.58% (196 cases) AAA-related mortality (NNT 371)

0.4% (135 cases) vs. 0.76% (257 cases) ruptured AAA (fatal or non-fatal) (NNT 278)

20.3% vs. 21% all-cause mortality (p = 0.05, NNT 143)

incremental cost-effectiveness ratio at 7 years

$19,500 per life-year gained using AAA-related mortality

$7,600 per life-year gained using all-cause mortality

Reference - Ann Intern Med 2007 May 15;146(10):699, editorial can be found in Ann Intern Med 2007 May 15;146(10):749, commentary can be found in ACP J Club 2007 Nov-Dec;147(3):57 screening all men > 65 years old reduces mortality in Danish population (level 1 [likely reliable] evidence)


12,639 Danish men > 65 years old randomized to abdominal ultrasound screening vs. no screening

participants with abdominal aortic aneurysm > 5 cm referred for surgical evaluation, participants with smaller aneurysms offered annual scans

mean follow-up 52 months

among 6,333 men in screening group, 4,860 (76.6%) were screened, 191 of those screened (4%) had abdominal aortic aneurysms

comparing screening vs. no screening

5 vs. 20 patients had emergency operation (NNT 420)

9 vs. 27 death due to AAA (NNT 352)

939 [14.8%] vs. 1,019 [16.2%] overall mortality (NNT 72)

Reference - BMJ 2005 Apr 2;330(7494):750 full-text, commentary can be found in Am Fam Physician 2005 Aug 15;72(4):680, ACP J Club 2005 Sep-Oct;143(2):39 population-based screening may reduce AAA mortality in men aged 65-75 years (level 2 [mid-level] evidence)

based on subgroup analysis of randomized trial

41,000 men aged 65-83 years in western Australia randomized to receive vs. not receive invitation for ultrasound screening

70% of those invited were screened

7.2% had aortic diameter at least 3 cm, 0.5% had aortic diameter at least 5.5 cm

at 5 years, 107 vs. 54 patients had elective AAA surgery (p = 0.002)

18 vs. 25 died from aortic aneurysm (not statistically significant)

difference in death from aortic aneurysm in men aged 65-75 years was statistically significant

Reference - BMJ 2004 Nov 27;329(7477):1259, correction can be found in BMJ 2005 Mar 12;330(7491):596, commentary can be found in BMJ 2005 Mar 12;330(7491):601 offering screening ultrasound to men at age 65 years associated with reduced risk for AAA rupture (level 2 [mid-level] evidence)

based on randomized trial with borderline statistical significance

15,775 patients aged 65-80 years randomized to control vs. invitation for screening ultrasound and followed for up to 5 years

in screening group, patients rescanned annually if aneurysm 3-4.4 cm, rescanned every 3 months if aneurysm 4.5-5.9 cm

surgical criteria were aneurysm > 6 cm, increase in diameter > 1 cm/year, or development of symptoms attributable to aneurysm

of those invited for screening, 68.4% accepted

4% had AAA (7.6% in men, 1.3% in women)

41% of those with AAA satisfied criteria for surgery, and 16% had surgery

none of 31 patients who had elective surgery died within 1 year, whereas 3 of 4 who had emergency surgery died (all 3 had been considered unfit for surgery)

of 2,493 people who declined screening initially, 5 died from ruptured AAA

in control group, 20 men and 2 women presented with ruptured AAA, 19 of whom died within 1 year

comparing screening invitation vs. control in men


0.25% vs. 0.5% mortality from AAA rupture (not significant)

0.28% vs. 0.62% incidence of ruptured AAA (NNT 295)

comparing screening invitation vs. control in women


0.064% vs. 0.043% mortality from AAA rupture (not significant)

0.064% vs. 0.043% incidence of ruptured AAA (not significant)

Reference - Br J Surg 1995 Aug;82(8):1066, commentary can be found in POEMs in J Fam Pract 1996 Apr;42(4):350 potentially cost-effective approaches to AAA screening for men at age 60-80 years

single screening with abdominal palpation

single screening with ultrasound

repeated screening not cost-effective

Reference - systematic review by Canadian Task Force on the Periodic Health Examination (Ann Intern Med 1993 Sep 1:119(5):411 full-text)

rescreening men with negative initial screen at 4 years reported to have little practical value (level 3 [lacking direct] evidence)

based on large cohort study without long-term follow-up

5,151 veterans aged 50-79 without AAA (defined as > 3 cm) on initial ultrasound randomly selected for rescreening

11.6% had died (not related to AAA)

0.4% had interim diagnosis of AAA

2,622 patients were rescreened and 58 (2.2%) had AAA but most were small (45 were 3-3.5 cm, 10 were 3.5-4 cm, 3 were 4-4.9 cm)

Reference - Arch Intern Med 2000 Apr 24;160(8):1117 review of ultrasound screening can be found in Ann Intern Med 2003 Sep 16;139(6):516, correction can be found in Ann Intern Med 2003 Nov 18;139(10):873, summary can be found in Am Fam Physician 2004 Mar 1;69(5):1247

discussion of evidence for national screening program in United Kingdom can be found in BMJ 2004 May 8;328(7448):1122, editorial can be found in BMJ 2004 May 8;328(7448):1087 (correction can be found in BMJ 2004 Jun 19;328(7454):1486)

References including Reviews and Guidelines

General references used:

American College of Cardiology/American Heart Association (ACC/AHA) 2005 guidelines for peripheral arterial disease (lower extremity, renal, mesenteric and abdominal aortic) (J Am Coll Cardiol 2006 Mar 21;47(6):1239 PDF)

AHRQ Evidence Report on Abdominal Aortic Aneurysm, Endovascular and Open Surgical Repairs 2006 Aug:144

MEDLINE search 2007 Feb 7 using PubMed Clinical Queries (therapy) for "abdominal aortic aneurysm"

Click for Details Click here to repeat MEDLINE search

40 studies included in this summary

Leurs LJ, Buth J, Harris PL, Blankensteijn JD. Impact of Study Design on Outcome after Endovascular Abdominal Aortic Aneurysm Repair. A Comparison between the Randomized Controlled DREAM-trial and the Observational EUROSTAR-registry. Eur J Vasc Endovasc Surg. 2007 Feb;33(2):172-6.

Rutherford RB. Endovascular aneurysm repair and outcome in patients unfit for open repair of abdominal aortic aneurysm (EVAR trial 2): randomized controlled trial. Perspect Vasc Surg Endovasc Ther. 2006 Mar;18(1):76-7.

Rutherford RB. Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomized controlled trial. Perspect Vasc Surg Endovasc Ther. 2006 Mar;18(1):74-6.

Senekowitsch C, Assadian A, Assadian O, Hartleb H, Ptakovsky H, Hagmuller GW. Replanting the inferior mesentery artery during infrarenal aortic aneurysm repair: influence on postoperative colon ischemia. J Vasc Surg. 2006 Apr;43(4):689-94.

Laohapensang K, Rerkasem K, Chotirosniramit N. Mini-laparotomy for repair of infrarenal abdominal aortic aneurysm. Int Angiol. 2005 Sep;24(3):238-44.

Laohapensang K, Rerkasem K, Chotirosniramit N. Left retroperitoneal versus midline transperitoneal approach for abdominal aortic aneurysms (AAAs) repair. J Med Assoc Thai. 2005 May;88(5):601-6.

Soulez G, Therasse E, Monfared AA, Blair JF, Choiniere M, Elkouri S, Beaudoin N, Giroux MF, Cliche A, Lelorier J, Oliva VL. Pain and quality of life assessment after endovascular versus open repair of abdominal aortic aneurysms in patients at low risk. J Vasc Interv Radiol. 2005 Aug;16(8):1093-100.

EVAR trial participants. Endovascular aneurysm repair and outcome in patients unfit for open repair of abdominal aortic aneurysm (EVAR trial 2): randomised controlled trial. Lancet. 2005 Jun 25-Jul 1;365(9478):2187-92.

EVAR trial participants. Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomised controlled trial. Lancet. 2005 Jun 25-Jul 1;365(9478):2179-86.

Blankensteijn JD, de Jong SE, Prinssen M, van der Ham AC, Buth J, van Sterkenburg SM, Verhagen HJ, Buskens E, Grobbee DE; Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2005 Jun 9;352(23):2398-405.

Lindholt JS, Juul S, Fasting H, Henneberg EW. Screening for abdominal aortic aneurysms: single centre randomised controlled trial. BMJ. 2005 Apr 2;330(7494):750.

Mercer KG, Spark JI, Berridge DC, Kent PJ, Scott DJ. Randomized clinical trial of intraoperative autotransfusion in surgery for abdominal aortic aneurysm. Br J Surg. 2004 Nov;91(11):1443-8.

Norman PE, Jamrozik K, Lawrence-Brown MM, Le MT, Spencer CA, Tuohy RJ, Parsons RW, Dickinson JA. Population based randomised controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ. 2004 Nov 27;329(7477):1259.

Prinssen M, Verhoeven EL, Buth J, Cuypers PW, van Sambeek MR, Balm R, Buskens E, Grobbee DE, Blankensteijn JD; Dutch Randomized Endovascular Aneurysm Management (DREAM)Trial Group. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2004 Oct 14;351(16):1607-18.

Greenhalgh RM, Brown LC, Kwong GP, Powell JT, Thompson SG; EVAR trial participants. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet. 2004 Sep 4-10;364(9437):843-8.

Lederle FA, Johnson GR, Wilson SE, Acher CW, Ballard DJ, Littooy FN, Messina LM; Aneurysm Detection and Management Veterans Affairs Cooperative Study. Quality of life, impotence, and activity level in a randomized trial of immediate repair versus surveillance of small abdominal aortic aneurysm. J Vasc Surg. 2003 Oct;38(4):745-52.

Vammen S, Lindholt JS, Ostergaard LJ, Fasting H, Henneberg EW. [Reduction of the expansion rate of small abdominal aortic aneurysms with roxithromycin. Results from a randomized controlled trial] Ugeskr Laeger. 2002 Dec 9;164(50):5916-9.

Ashton HA, Buxton MJ, Day NE, Kim LG, Marteau TM, Scott RA, Thompson SG, Walker NM; Multicentre Aneurysm Screening Study Group. The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet. 2002 Nov 16;360(9345):1531-9.

Multicentre Aneurysm Screening Study Group. Multicentre aneurysm screening study (MASS): cost effectiveness analysis of screening for abdominal aortic aneurysms based on four year results from randomised controlled trial. BMJ. 2002 Nov 16;325(7373):1135.

United Kingdom Small Aneurysm Trial Participants. Long-term outcomes of immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med. 2002 May 9;346(19):1445-52.

Lederle FA, Wilson SE, Johnson GR, Reinke DB, Littooy FN, Acher CW, Ballard DJ, Messina LM, Gordon IL, Chute EP, Krupski WC, Busuttil SJ, Barone GW, Sparks S, Graham LM, Rapp JH, Makaroun MS, Moneta GL, Cambria RA, Makhoul RG, Eton D, Ansel HJ, Freischlag JA, Bandyk D; Aneurysm Detection and Management Veterans Affairs Cooperative Study Group. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med. 2002 May 9;346(19):1437-44.

Matsumoto M, Hata T, Tsushima Y, Hamanaka S, Yoshitaka H, Shinoura S, Sakakibara N. Minimally invasive vascular surgery for repair of infrarenal abdominal aortic aneurysm with iliac involvement. J Vasc Surg. 2002 Apr;35(4):654-60.

Propanolol Aneurysm Trial Investigators. Propranolol for small abdominal aortic aneurysms: results of a randomized trial. J Vasc Surg. 2002 Jan;35(1):72-9.

Wong JC, Torella F, Haynes SL, Dalrymple K, Mortimer AJ, McCollum CN; ATIS Investigators. Autologous versus allogeneic transfusion in aortic surgery: a multicenter randomized clinical trial. Ann Surg. 2002 Jan;235(1):145-51.

Mosorin M, Juvonen J, Biancari F, Satta J, Surcel HM, Leinonen M, Saikku P, Juvonen T. Use of doxycycline to decrease the growth rate of abdominal aortic aneurysms: a randomized, double-blind, placebo-controlled pilot study. J Vasc Surg. 2001 Oct;34(4):606-10.

Vammen S, Lindholt JS, Ostergaard L, Fasting H, Henneberg EW. Randomized double-blind controlled trial of roxithromycin for prevention of abdominal aortic aneurysm expansion. Br J Surg. 2001 Aug;88(8):1066-72.

Tornwall ME, Virtamo J, Haukka JK, Albanes D, Huttunen JK. Life-style factors and risk for abdominal aortic aneurysm in a cohort of Finnish male smokers. Epidemiology. 2001 Jan;12(1):94-100.

Brady AR, Fowkes FG, Greenhalgh RM, Powell JT, Ruckley CV, Thompson SG. Risk factors for postoperative death following elective surgical repair of abdominal aortic aneurysm: results from the UK Small Aneurysm Trial. On behalf of the UK Small Aneurysm Trial participants. Br J Surg. 2000 Jun;87(6):742-9.

Lederle FA, Johnson GR, Wilson SE, Chute EP, Hye RJ, Makaroun MS, Barone GW, Bandyk D, Moneta GL, Makhoul RG. The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med. 2000 May 22;160(10):1425-30.

Vardulaki KA, Walker NM, Day NE, Duffy SW, Ashton HA, Scott RA. Quantifying the risks of hypertension, age, sex and smoking in patients with abdominal aortic aneurysm. Br J Surg. 2000 Feb;87(2):195-200.

Brown LC, Powell JT. Risk factors for aneurysm rupture in patients kept under ultrasound surveillance. UK Small Aneurysm Trial Participants. Ann Surg. 1999 Sep;230(3):289-96.

Lindholt JS, Henneberg EW, Juul S, Fasting H. Impaired results of a randomised double blinded clinical trial of propranolol versus placebo on the expansion rate of small abdominal aortic aneurysms. Int Angiol. 1999 Mar;18(1):52-7.

Clagett GP, Valentine RJ, Jackson MR, Mathison C, Kakish HB, Bengtson TD. A randomized trial of intraoperative autotransfusion during aortic surgery. J Vasc Surg. 1999 Jan;29(1):22-30.

[No authors listed] Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. The UK Small Aneurysm Trial Participants. Lancet. 1998 Nov 21;352(9141):1649-55.

Spark JI, Chetter IC, Kester RC, Scott DJ. Allogeneic versus autologous blood during abdominal aortic aneurysm surgery. Eur J Vasc Endovasc Surg. 1997 Dec;14(6):482-6.

Farrer A, Spark JI, Scott DJ. Autologous blood transfusion: the benefits to the patient undergoing abdominal aortic aneurysm repair. J Vasc Nurs. 1997 Dec;15(4):111-5.

Sieunarine K, Lawrence-Brown MM, Goodman MA. Comparison of transperitoneal and retroperitoneal approaches for infrarenal aortic surgery: early and late results. Cardiovasc Surg. 1997 Feb;5(1):71-6.

Scott RA, Wilson NM, Ashton HA, Kay DN. Influence of screening on the incidence of ruptured abdominal aortic aneurysm: 5-year results of a randomized controlled study. Br J Surg. 1995 Aug;82(8):1066-70.

Sicard GA, Reilly JM, Rubin BG, Thompson RW, Allen BT, Flye MW, Schechtman KB, Young-Beyer P, Weiss C, Anderson CB. Transabdominal versus retroperitoneal incision for abdominal aortic surgery: report of a prospective randomized trial. J Vasc Surg. 1995 Feb;21(2):174-81.

Samy AK, Murray G, MacBain G. Glasgow aneurysm score. Cardiovasc Surg. 1994 Feb;2(1):41-4.

7 studies included in summarized systematic reviews

Norman JG, Fink GW. The effects of epidural anesthesia on the neuroendocrine response to major surgical stress: a randomized prospective trial. Am Surg. 1997 Jan;63(1):75-80.

[No authors listed] The U.K. Small Aneurysm Trial: design, methods and progress. The UK Small Aneurysm Trial participants. Eur J Vasc Endovasc Surg. 1995 Jan;9(1):42-8.

Gold MS, Russo J, Tissot M, Weinhouse G, Riles T. Comparison of hetastarch to albumin for perioperative bleeding in patients undergoing abdominal aortic aneurysm surgery. A prospective, randomized study. Ann Surg. 1990 Apr;211(4):482-5.

Prinssen M, Buskens E, Nolthenius RP, van Sterkenburg SM, Teijink JA, Blankensteijn JD. Sexual dysfunction after conventional and endovascular AAA repair: results of the DREAM trial. J Endovasc Ther. 2004 Dec;11(6):613-20.

Prinssen M, Buskens E, Blankensteijn JD; DREAM trial participants. Quality of life endovascular and open AAA repair. Results of a randomised trial. Eur J Vasc Endovasc Surg. 2004 Feb;27(2):121-7.

Scott RA, Bridgewater SG, Ashton HA. Randomized clinical trial of screening for abdominal aortic aneurysm in women. Br J Surg. 2002 Mar;89(3):283-5.

Scott RA, Vardulaki KA, Walker NM, Day NE, Duffy SW, Ashton HA. The long-term benefits of a single scan for abdominal aortic aneurysm (AAA) at age 65. Eur J Vasc Endovasc Surg. 2001 Jun;21(6):535-40. 166 studies not included in this summary

Hoornweg LL, Wisselink W, Vahl A, Balm R; On behalf of the Amsterdam Acute Aneurysm Trial Collaborators. The Amsterdam Acute Aneurysm Trial: Suitability and Application Rate for Endovascular Repair of Ruptured Abdominal Aortic Aneurysms. Eur J Vasc Endovasc Surg 2007 Jun;33(6):679

Dale W, Hemmerich J, Ghini EA, Schwarze ML. Can induced anxiety from a negative earlier experience influence vascular surgeons' statistical decision-making? A randomized field experiment with an abdominal aortic aneurysm analog. J Am Coll Surg. 2006 Nov;203(5):642-52.

Moore NN, Lapsley M, Norden AG, Firth JD, Gaunt ME, Varty K, Boyle JR. Does N-acetylcysteine prevent contrast-induced nephropathy during endovascular AAA repair? A randomized controlled pilot study. J Endovasc Ther. 2006 Oct;13(5):660-6.

Ward HB, Kelly RF, Thottapurathu

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