Multidisciplinary Histological and Mechanical Study of Aortic Aneurysm to Investigate Potential Parameters for Early Diagnosis of High Risk Rupture Pasquale

Multidisciplinary Histological and Mechanical Study

of Aortic Aneurysm to Investigate Potential

Parameters for Early Diagnosis of High Risk Rupture

Pasquale Totaro MD,PhD

Division of Cardiothoracic SurgeryCenter for Genetic Cardiovascular PathologyIRCCS Foundation Hospital “San Matteo”, PAVIA -Italy

Computational Mechanics, Department of EngineeringUniversity of Pavia

AATS 2015Seattle

P.Totaro

IRCCS San Matteo,Pavia-Italy

University of Pavia

Background

Optimization of decision making process in patients

presenting with ascending aorta aneurysm is still

debated

AATS 2015Seattle

P.Totaro


University of Pavia

Background

Optimization of decision making process in patients

presenting with ascending aorta aneurysm is still

debated

Despite several studies have been designed to evaluate potential predictive risk factors for early complications, maximum diameter still remains the key criteria for surgical indication

AATS 2015Seattle

P.Totaro


University of Pavia

Background

AATS 2015Seattle

P.Totaro


University of Pavia

Objective

To investigate potential markers of early

complication in patients presenting with aortic

aneurysm we have analyzed the mechanical

characteristics of aortic wall and we have tried to

correlate these results to preoperative parameters

and histological intraoperative evaluation

AATS 2015Seattle

P.Totaro


University of Pavia

Uniaxial Testing Device

One or more test each Region/Orientation

configuration

Electromechanic Tension MTS Insight 10 kN (MTS System Corporation)

AATS 2015Seattle

P.Totaro


University of Pavia

CircumferentialL

on

gitu

din

al

163 (66%)

71 (29%)

92 (37%)

Circumferential

Lo

ng

itud

inal

84(34%)

32 (13%)

52 (21%)

Overall Specimens: 403 Accepted Test: 247 (62%)

Patients: 46 Samples:86

A1

A2

A3

P1

P2

AATS 2015Seattle

P.Totaro


University of Pavia

U• Pstr = Peek Stress (Mpa)

• EM = Maximum Elastic Modulus (Mpa)

• PS = Peek Strein (mm/min)

U

MAXE

U

1. Preconditioning 2. Failure Test

Materials and Methods

AATS 2015Seattle

P.Totaro


University of Pavia

Age (> 60 yo)GenderDiameter (> 5cm)Indexed Diameter (>25)Bicuspid ValveHypertensionAortic Insufficiency

Preoperative Data Aortic Elasticity *Preoperative TTE

Evaluation

Aortic Distensibility(10-6cm2dyn-1)

Aortic Stiffness Index

Aortic Strein

Histological Evaluation

Elastolisis

Mucoid Tissue

Cystic Medionecrosis

Disarrey


* Ikonomidis et al, JACC 2004

Pulse Pressure(dyne)

AATS 2015Seattle

P.Totaro


University of Pavia

Age (> 60 yo)GenderDiameter (> 5cm)Indexed Diameter (>25)Bicuspid ValveHypertensionAortic Insufficiency

Preoperative Data Aortic Elasticity *Preoperative TTE

Evaluation

Aortic Distensibility(10-6cm2dyn-1)

Aortic Stiffness Index

Aortic Strein

* Ikonomidis et al, JACC 2004

Histological Evaluation

Elastolisis

Mucoid Tissue

Cystic Medionecrosis

Disarrey

Quantitative Score

HATS (0-16)


Pulse Pressure(dyne)

AATS 2015Seattle

P.Totaro


University of Pavia

Results – 1 (247 tests)

p<0,0001

p<0,0001

Pstr/Orientation EM/Orientation

AATS 2015Seattle

P.Totaro


University of Pavia

p<0,0001

p<0,0001

p<0,0001PS

Pstr

EM

Impact of preoperative parameters:

Age >60


AATS 2015Seattle

P.Totaro


University of Pavia


p<0,000001p<0,000001

No significant differences No significant differences

AATS 2015Seattle

P.Totaro


University of Pavia

p<0,000001p<0,000001

No significant differences No significant differences


AATS 2015Seattle

P.Totaro


University of Pavia

Age > 60 yo

Gender

Diameter > 5cm

ID >25

Bicuspid Valve

?

Preoperative Risk Factors Analysis


AATS 2015Seattle

P.Totaro


University of Pavia

Age > 60 yo

Gender

Diameter > 5cm

ID >25

Bicuspid Valve

Preoperative Risk Factors Analysis

P=0,027


AATS 2015Seattle

P.Totaro


University of Pavia

p= NS (PL)p= NS (PC,PL)

p= 0,001 (AC,AL)

p= NS (PC,PL)

p= 0,001 (AC,AL)p= 0,0001 (AC,AL,PC)


AATS 2015Seattle

P.Totaro


University of Pavia

p= 0,006 (AC)

p= 0,003 (AC,PC)Correlation to TTE Aortic Elasticity Evaluation


AATS 2015Seattle

P.Totaro


University of Pavia

p=0,008

p=0,0047

Correlation to Histological Evaluation


AATS 2015Seattle

P.Totaro


University of Pavia

Results - 3

AATS 2015Seattle

P.Totaro


University of Pavia


P=0,02 (BV)

P=0,04 (no BV)

AATS 2015Seattle

P.Totaro


University of Pavia

P=0,0056 (no BV)P=0,0112 (F)

Correlation to TTE Aortic Elasticity Evaluation


AATS 2015Seattle

P.Totaro


University of Pavia

P=0,0129

P=0,045 (BV)



AATS 2015Seattle

P.Totaro


University of Pavia

P=0,0019



AATS 2015Seattle

P.Totaro


University of Pavia


p=0,0034

AATS 2015Seattle

P.Totaro


University of Pavia

p<0,000001

p=0,0034


AATS 2015Seattle

P.Totaro


University of Pavia

P<0,0001

p<0,000001


AATS 2015Seattle

P.Totaro


University of Pavia

Conclusions - 1

Mechanical characteristics of aortic wall do vary according the

region of the aorta and the force applied.

Biomechanical characterization of aortic wall, therefore, has to

be defined only with multiple tests from multiple specimens.

Age is surely related to an impairment of mechanical properties

The posterior region of the aorta seems to be more frail

especially when a longitudinal force is applied regardless age of

patients

AATS 2015Seattle

P.Totaro


University of Pavia

Conclusions - 2

There are significant correlations between increased maximum

diameter, histological abnormalities and reduced strength of

aortic wall.

These correlations, however, do vary according different regions

of the aorta and the type of force applied.

Presence of bicuspid valve does not seem to impact significantly

the mechanical properties of aortic wall

Preoperative evaluation of aortic elasticity may help to identify

patients with impaired mechanical properties

Dad Come Back Home Please

Thank You

Documents

Multidisciplinary Histological and Mechanical Study of Aortic Aneurysm to Investigate Potential Parameters for Early Diagnosis of High Risk Rupture Pasquale