New Concept of Microporous Structure in Small Diameter Vascular Prostheses

Six types of skinned and microporous vascular prostheses (1.5 mm ID) with different hydraulic permeabilities (HP) were fabricated with either a polyurethane polydimethylsiloxane (PU-PDMS) or a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) by the spray phase inversion technique: skinned PU-PDMS grafts with an HP of 0 ml/min/cm2 (PU-PDMS-S-0), microporous surfaced PU-PDMS grafts with an HP of 2.7 ml/min/cm2 (PU-PDMS-2.7), microporous surfaced PU-PDMS grafts with an HP of 39 ml/min/cm2 (PU-PDMS-39), poled skinned PVDF-TrFE grafts with an HP of 0 ml/min/cm2 (poled PVDF-TrFE-S-0), poled microporous surfaced PVDF-TrFE grafts with an HP of 41 ml/min/cm2 (poled PVDF-TrFE-41), and unpoled microporous surfaced PVDF-TrFE grafts with an HP of 41 ml/min/cm2 (unpoled PVDF-TrFE-41). Straight segments of these grafts (1.5-2.2 cm in length) and one loop PU-PDMS-39 (10 cm in length) were implanted in the rat infrarenal aorta. Graft surface morphology and wall porosity as reflected by hydraulic permeability were the main determinants of early patency and completeness of healing including endothelialization.