6533b831fe1ef96bd1299b76

RESEARCH PRODUCT

Identification of circumferential regional heterogeneity of ascending thoracic aneurysmal aorta by biaxial mechanical testing

Salvatore PastaGioacchino AlottaMichele PilatoGiuseppe Maria RaffaDiego BellaviaMarzio Di GiuseppeValentina AgneseMassimiliano ZingalesValeria Vetri

subject

0301 basic medicineAortic valveMaleMaterial parameterBicuspid aortic valveHeart Valve DiseasesAorta Thoracic030204 cardiovascular system & hematologyThoracic aortic aneurysm03 medical and health sciences0302 clinical medicineBicuspid aortic valveAneurysmVascular StiffnessBicuspid Aortic Valve Diseasemedicine.arteryMedicineHumansIn patientMolecular BiologyAgedAged 80 and overAortaAortic Aneurysm Thoracicbusiness.industryAscending aortic aneurysmSettore ING-IND/34 - Bioingegneria IndustrialeAnatomyMiddle Agedmedicine.diseaseSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)Tissue stiffness030104 developmental biologymedicine.anatomical_structureAortic Valvecardiovascular systemFemaleTissue stiffnessCardiology and Cardiovascular MedicinebusinessBiaxial testingSettore ICAR/08 - Scienza Delle CostruzioniElastic fiberDilatation Pathologic

description

Abstract Ascending thoracic aortic aneurysm (ATAA) in patients with bicuspid aortic valve (BAV) can present an asymmetrical aortic dilatation compared with patients with tricuspid aortic valve (TAV). This pattern of aneurysm dilatation led us to hypothesize that biomechanical differences likely induced by regional heterogeneity of material properties can underlie the observed asymmetric enlargement discrepancies between BAV ATAA and TAV ATAA. This study aimed to characterize the mechanical properties and associated aortic tissue stiffness changes along the circumferential direction of aortic rings collected from surgically-repaired patients with ATAA. Biaxial material testing was performed on tissue specimens extrapolated from all aortic quadrants (i.e. anterior, posterior, major and minor curvature of the aorta), and then the tissue stiffness was quantified at both physiological and supra-physiological stress levels (i.e. 142 kPa and 242 kPa, respectively). Tissue stiffness revealed that the major curvature of BAV ATAA is statistically less stiff than the anterior quadrant (276.6 ± 137.1 kPa for BAV ATAA and 830.1 ± 557.1 kPa for BAV ATAA, p = .024, at 142 kPa) and to that of major curvature of TAV ATAA (276.6 ± 137.0 kPa for BAV ATAA and 733.2 ± 391.1 kPa for TAV ATAA, p = .001, at 142 kPa), suggesting local weakening of bicuspid aortic wall. Multiphoton imaging revealed local changes on elastic fiber networks. The recovered material parameters for the Fung-type constitutive model are crucial for reliable stress predictions while the information on regional tissue stiffness changes are fundamental to develop risk stratification strategies not based on aortic size.

yearjournalcountryeditionlanguage
2019-05-01
10.1016/j.yjmcc.2019.04.010http://hdl.handle.net/10447/376238