Evaluation of materials used for vascular anastomoses using shear wave elastography

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Medical Device Development

Background:

• Cardiovascular disease is a leading cause of mortality, with peripheral artery disease (PAD) significantly impacting the elderly.
• Current synthetic vascular grafts like Dacron and ePTFE exhibit stiffness mismatch with native arteries.
• Developing compliant synthetic vascular grafts is crucial for improving treatment outcomes in PAD patients.

Purpose of the Study:

• To compare the mechanical behavior of a novel polyvinyl alcohol cryogel reinforced arterial model (PRAM) with native aortas and existing synthetic grafts.
• To evaluate the suitability of PRAM as a vascular graft material by assessing its mechanical properties under physiological conditions.
• To investigate the potential of PRAM to improve vascular graft performance by achieving better mechanical matching with host arteries.

Main Methods:

• Utilized shear wave elastography (SWE) to measure the group velocity in the vessel walls of excised aortas and synthetic grafts (Dacron, ePTFE, PRAM).
• Tested materials under varying physiological conditions, including initial longitudinal strains (0%-40%) and transmural pressures (20-180 mmHg).
• Quantified and compared the mechanical properties, specifically group velocity, across different graft materials and native aortic tissue.

Main Results:

• PRAM materials demonstrated group velocity values closer to excised aortas compared to Dacron and ePTFE.
• The ratio of group velocity for PRAM to aortas ranged from 0.83 to 1.13, indicating better mechanical compliance.
• Dacron and ePTFE exhibited significantly higher group velocity ratios (1.12-2.22 and 1.91-3.10, respectively), signifying greater stiffness.

Conclusions:

• PRAM materials exhibit superior mechanical matching with native aortas compared to conventional synthetic grafts.
• The findings suggest PRAM is a promising alternative biomaterial for vascular grafting, potentially improving functional vessel patency and limb salvage in PAD treatment.
• Further research into PRAM could lead to the development of more effective and compliant vascular prostheses.