Functional properties of fresh and cryopreserved carotid and femoral arteries, and of venous and synthetic grafts: comparison with arteries from normotensive and hypertensive patients

Abstract

The ideal arterial graft must share identical functional properties with the host artery. Surgical reconstruction of the common carotid artery (CA) is performed in several clinical situations, using expanded polytetrafluoroethylene prosthesis (ePTFE) or saphenous vein (SV) grafts. At date there is interest in obtaining an arterial graft that improves the results of that nowadays available. The use of a fresh or cryopreserved/defrosted artery appears as an interesting alternative. However, if the fresh and cryopreserved/defrosted arteries allow an adequate viscoelastic and functional matching with the host arteries needs to be established. The aims were to compare the viscoelastic and functional performance of: (1) conduits used in CA reconstruction (SV and ePTFE) with those of the fresh and cryopreserved/ defrosted CA and femoral arteries (FA), and (2) normotensive and hypertensive patients' arteries with those of the arterial substitutes in vitro analyzed. Pressure, diameter and wall thickness of the CA were recorded in 15 normotensive and 15 hypertensive patients (in vivo studies), and in SV, fresh and cryopreserved/defrosted CA and FA (obtained from 15 donors), and ePTFE segments (in vitro studies). From stress-strain relationship we calculated elastic and viscous modulus, and the characteristic impedance. The local buffer and conduit functions were quantified as the viscous/elastic quotient and the inverse of the characteristic impedance. Fresh and cryopreserved/defrosted CA and FA were more alike, both in viscoelastic and functional levels, respect to normotensive and hypertensive patients' arteries, than the ePTFE and SV grafts. CA and FA cryografts could be considered an important alternative for carotid reconstruction.

ECM-based triple layered scaffolds for vascular tissue engineering

“…The longitudinal TS values of our TLVGs (0.47±0.02 MPa) were higher compared to those (0.24±0.10 MPa) of triple layered scaffolds prepared by Koens et al (9). Furthermore, the Young's modulus of our TLVGs (1.8 MPa) was comparable to that of porcine coronary artery (1 MPa) (31), rabbit aorta (1.25 MPa) (32) and human saphenous or femoral vein (1.50 MPa) (33). Scaffold strength provides the firmness to resist cell contraction forces, whereas elasticity enables better communication between cells, facilitating parallel organization (27,37,38) and ensuring the maintenance of a tubular shape in our constructs.…”

“…The layer deposition procedure allowed us to obtain smalldiameter TLVGs of different sizes using DAM from bovine aorta containing ECM components, which are naturally present in blood vessels. Our findings show that these novel tailor-made vascular grafts present mechanical properties comparable to those of native vessels (31)(32)(33). Furthermore, the lyophilization process makes them easy to store.…”

“…Mechanical characterization revealed that TLVGs generally showed a significant increase of the TS with respect to natural vessels of comparable diameter. However, the Young's modulus measured (1.8 MPa) was comparable to that of porcine coronary artery (1 MPa) (31), rabbit aorta (1.25 MPa) (32) and human saphenous or femoral vein (1.50 MPa) (33).…”

Structural and Functional Properties of Venous Wall: Relationship between Elastin, Collagen, and Smooth Muscle Components and Viscoelastic Properties

“…On the other hand, the biomechanical studies conducted on the venous wall correspond mainly to the field of strength of materials and are nonrealistic, static, and carried out in nonphysiological conditions [5]. Furthermore, most works do not refer to the viscous response of the wall [6]. In this context, the purpose of this work includes the characterization of the venous functional biomechanical behavior, through the analysis of the dynamic biomechanical response of the venous wall, under a hemodynamic setting that resembles physiological conditions.…”

Angiographically confirmed stent over expansion in the internal carotid artery during stenting: incidence, predictors, and outcomes

“…Therefore, the exact pre-procedural evaluation of the distal ICA diameter is difficult. Although Santana et al reported the elastic modulus of the carotid artery as 707 KPa [15], there may be individual differences with respect to the ICA. The ICA with a lower elastic modulus may be easily expanded by oversized stents and reduce the chronic expansile force promoting greater neointimal hyperplasia.…”