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Biomechanics

Aortic Valve: investigation by engineering tools

Università degli Studi di Pavia - Structural Mechanics Department

2The procedure requires high technical expertise Procedure Planning

Effects of Aortic root delation

- Coaptazion area reduction- Valve incompetence

Aortic Valve

AORTIC VALVE SPARING PROCEDURE

1) Excision of aortic root in order to achieve an ad hocstructure containing the native valve

2) Anchoring of the prosthesis tube, replacing ascending aorta, and excised aortic valve

3) Whole re-implanted aortic valve, within prosthesis tube, presenting mercedes star like shape

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Image analysis

Approach 1: closed configuration Approach 2: open configuration

Patient

Medical images

Geometric model

Finite element analysis

Output

Boundary conditions

K1,..,Kn

Aortic Valve

GENERATION OF GEOMETRIC MODEL

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METHOD FOR THE MESH GENERATION

Aortic Valve

Parametric model reproduces 1/6 of the aortic valve

Mirroring operation���� 1/3 of the aortic valve

Finally, by a circular replication ����whole model of the aortic valve in open configuration

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Rb Rb

Ht Ht

F

� �

Aortic Valve

HrF

PARAMETERS OF THE MODEL (1/6 OF VALVE)Different views of the same element:

• base radius, Rb [13 mm] *• total height, Ht [16.8 mm]

• maximum height of the aortic root, Hr [10.8 mm]• slope of the aortic root, � [6°]• slope of the leaflet, � [7°]• parameters of the “intermediate-line” function

* Parameter Values based on Labrosse et al. 2006

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Image analysis

Patient

Medical images

Geometric model

Finite element analysis

Output

Boundary conditions

Aortic Valve

NUMERICAL SIMULATIONS – “HEALTH” VALVE

Bottom viewSide view

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Aortic Valve

NUMERICAL SIMULATIONS – PATHOLOGIC VALVE

Bottom viewSide view

Top viewSide viewBottom view

Valve is not able to close completely

Pathologic aortic valve model is generated enlarging aortic root