Microporous small diameter PVDF-TrFE vascular grafts fabricated by a spray phase inversion technique

Area of Science:

• Biomaterials Science
• Vascular Surgery
• Polymer Chemistry

Background:

• Microporous vascular prostheses are crucial for replacing damaged blood vessels.
• Piezoelectric materials offer potential for enhanced biological interaction in implants.
• Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) is a promising co-polymer for biomedical applications.

Purpose of the Study:

• To evaluate the effect of piezoelectric properties on the patency and biocompatibility of PVDF-TrFE vascular grafts.
• To compare the performance of poled (piezoelectric) and unpoled PVDF-TrFE grafts in a rat infrarenal aorta model.

Main Methods:

• Fabrication of microporous PVDF-TrFE co-polymer grafts (1.5 mm internal diameter) using spray phase inversion.
• Poling of experimental grafts to induce piezoelectricity.
• Implantation of 48 poled (P) and 24 unpoled (UP) grafts into the infrarenal aorta of adult rats.
• Assessment of graft patency, macroscopic, and microscopic findings at various time points (2 days, 2 weeks, 6 months).

Main Results:

• Overall patency rates were high for both groups: 92% for poled and 88% for unpoled grafts.
• No significant difference in patency was observed between poled and unpoled grafts at any time point.
• Both graft types exhibited excellent biocompatibility, with complete endothelialization by 6 months.
• Initial fibrin deposition was slightly higher in poled grafts, but no difference in platelet adhesion was noted.

Conclusions:

• The piezoelectric properties of PVDF-TrFE grafts did not significantly influence their patency or biocompatibility in this rat model.
• The inherent properties of the PVDF-TrFE co-polymer and its microporous structure are likely the primary drivers of successful graft performance.
• The piezoelectric charges generated may have been insufficient to elicit a significant biological response.