Determination of AAA wall stiffness by nano-indentation, by Martin Hossack.

Martin Hossack

Liverpool

Vascular trainee

Repair only based on diameter is not dependable in terms ot doing / not doing; some rupture at smaller than threshold and in others the diameter does not correlate well with rupture risk.

Tensile testing only measures global property of material; rupture is a focal event.

They harvested reddndant aortic wall from 21 pts who had open repair

Oscillatory nano-indentation used to test the layers of the wall.

The histo analysis appears to have looked at Elastic Collagen and GAG

Median max diameter was 62 mm

The ‘elastic modulus’ varied widely

Found no correlation between maximum aortic diameter and median elastic modulus.

Summary:

There is a high variation in stiffness

Stifnes not related to diameter

Increased calcification and tissue disruption increase the stiffness.

Suggestion that calcium scoring should be incorporated into future rupture risk estimate methods.

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