Transcript Updates on Abdominal aortic aneurysm

Updates on Abdominal
aortic aneurysm
Yvonne Tsang
North District Hospital
Aneurysm


   
A permanent and
irreversible localized
dilatation of a vessel

Aorta with an infrarenal diameter > 30mm


McGregor JC. The value of ultrasonography in the diagnosis of abdominal aortic
aneurysm. Scott Med J 1975;20:133—37
Infrarenal diameter should be 1.5 times
the expected normal diameter

The Society for Vascular Surgery and the International
Society for the Cardiovascular Surgery in 1991
Epidemiology

Prevalence
 1.3
- 8.9% in men
 1.0 - 2.2% in women

Rupture of abdominal aortic aneurysms
 8000
death per year in UK
 15 000 death per year in US

Overall mortality rate of ruptured AAA
 65
– 85%
Histopathology
Fragmentation of elastic fibres
 Decrease in concentration of elastin
 Reduction in the density of smooth muscle
cells



Baxter BT et al. Elastin content, crosslinks, and mRNA in normal and
aneurysmal human aorta. J Vasc Surg 1992;16;192-200
Sakalihasan N et al. Modifications of the extracellular matrix of aneurysmal
abdominal aortas as a function of their size. Eur J Vasc Surg 1993;7;633-37
Diagnosis

Bimanual palpation

Sensitivity increases with diameter



61% for 3.0 – 3.9 cm
69% for 4.0 – 4.9 cm
82% for >= 5.0 cm

Fink HA. The accuracy of physical examination to detect abdominal aortic aneurysm.
Arch Intern Med 2000;160;833-36
 Ultrasonography
 Accuracy
of 3 mm
 For initial assessment,
 surveillance and
screening

Quill DS. Ultrasonic screening for
the detection of abdominal
aortic aneurysms. Surg Clin
North Am 1989;69;713-29

Computed Tomography
 Visualise
the proximal
neck, the extension to the
iliac arteries and the
patency of the visceral
arteries.
 Measure the thickness of
the mural thrombus

Angiogram
 CT
/ MRA
Clinical presentation

Unruptured
 Generally
asymptomatic
 After complications

Ruptured
 Triad
 Retroperitoneal
space
Indications for treatment

Indication for surgical treatment deduced
 Estimated
risk of rupture
 Estimated risk of surgical procedure
 Estimated life expectancy

Rigorous surveillance of intrarenal aortic
aneurysms < 5.5cm is safe

The UK Small ameurysm trial Participants. Mortality results for randomized
controlled trial of early elective surgery or ultrasonographic surveillance for
small abdominal aortic aneurysms. Lancet 1998;352;1649-55
Risk of elective aneurysm repair
Varies among hospital and surgeons
 Mean 30-day mortality 1.1 – 7%
 Risk factors

 Renal
failure
 COAD
 Myocardial
ischaemia
coronary artery revascularisation
before surgery?
Benefit remains controversial
 Simultaneous aneurysm repair and coronary
revascularisation recommended in selected
patient



El-Sabrout RA. Outcome after simltaneous abdominal arotic aneurysm repair and coronary
bypass. Ann Vasc Surg 2002;16;321-30
RCT > no significant difference in long-term
outcome when coronary artery revascularisation
undertaken before elective surgery

McFalls EO. Coronary-artery revascularisation before elective major vascular
surgery. N Eng J Med 2004;351;2795-804
Risk of emergency repair for ruptured
aneurysm

5 preoperative risk factors predict
mortality
 Age
> 76
 Creatinine > 190 umol/L
 Haemoglobin < 9 g/dL
 Loss of conscious
 ECG evidence of ischaemia
 Risk
factors
3
mortality
100
48
28
18
2
1
0

Prance SE. Ruptured abdominal aortic aneurysms: selected
patients for surgery. Eur J Vasc Endovasc Surg 1999;17;129-32
Management
surgery vs endovascular repair

Endovascular repair
 Introduced
by Parodi in
1991
 Placement of a graft across
the aneurysm and the
fixation to the normal
arotic and iliac wall with
stents at both ends
EVAR trial 1
Lancet 2005;365;2179-86
 Randomized controlled trial of 1082
patient aged >=60 with aneurysm >=
5.5cm
 Referred to one of 34 hospitals proficient
to EVAR
 EVAR (n=543) or open repair (n=539)

Higher number of complications and
reinterventions in EVAR
 Significance difference the aneurysmrelated mortality at 4 years

 4%
in EVAR vs 7% in open repair
EVAR higher cost and longer follow up
 After 4 years, all-cause mortality did not
differ

EVAR trial 2
Lancet 2005;365;2187-92
 Patients unfit for open repair
 Randomized controlled of 338 patients
aged >= 60 years with aneurysms >= 5.5
cm
 Referred to one of 31 hospitals in UK
 EVAR (n=166) or no intervention (n=172)

30-day operative mortality in EVAR was
9%
 No significant difference

 All-cause
mortality
 Aneurysm-related mortality

Conclusions
 EVAR
did not improve survival
 Need for continued surveillance and
reinterventions > increased cost
Emergency endovascular repair for
ruptured abdominal aortic aneurysms

First reported by Yusuf
et al in 1994

Yusuf SW et al.
Emergency endovascular
repair of leaking aortic
aneursym. Lancet
1999;344;1645

Retrospective reviews
 Improve
early outcomes
 Shorter ICU stay

Brandt M. Endovascular Repair of Ruptured Abdominal Aortic Aneurysm:
Feasibility and Impacy on Early Outcome. J Vasc Interv Radiol
2005;16;1309-12

Patients associated with heavy
comorbidities > no difference in mid-term
motality
Non-invasive prevention of growth
and rupture

Stop smoking reduces the growth of
aneurysm


Brady AR. Abdominal aortic aneurysm expansion: risk factors and time intervals
for surveillance. Circulation 2004;110;16-21
Tetracycline prevents aneurysm growth

Baxter BT. Prolonged administration of doxycycline in patient with small
asymptomatic abdominal aortic aneurysms: report of a prospective multicenter
study. J Vasc Surg 2002;36;1-12

β-blockers
 reduce
the growth rate of large (>5cm) aneurysm
and even to lessen the size


 no
effect on growth rate of small aneurysms


Gadowski GR. Abdominal aortic aneurysm expansion rate: effect of size and
beta-adrenergic blockade. J Vasc Surg 1994;19;727-31
Slaiby JM. Expansion of arotic aneurysms is reduced by propranolol in a
hypertensive rat model. J Vasc Surg 1994;20;178-83
Propranol Aneurysm Trial Investigators. Propranolol for small abdominal
aortic aneurysms; results of a randomized trial. J Vasc Surg 2002;35;72-79
Statins
 Reduce
expansion of various inflammatory
molecules
 Long term use reduced mortality after surgery

Kertai MD. Association between long-term statin use and mortality after
successful abdominal aortic aneurysm surgery. Am J Med 2004;116;96-103
conclusions

Marked progress in past few decades
 Diagnosis
 Management
 Timing
of interventional treatments
 Assessment of endovascular repair vs conventional
surgery

What comes next?
The End
Thank you