Abstract: The invention described herein consists of an expanded PTFE (ePTFE) material that contains a novel fibril and node structure that exhibits a pore size distribution of two or more distinct pore sizes. The pore size distribution of small pores inter-spaced with larger pores to create a mosaic pore structure is advantageous as a blood-contacting surface and renders the invention a very useful and advantageous vascular graft.

Abstract: A novel polytetrafluoroethylene (PTFE) material includes a plurality of aggregates connected together by a plurality of relatively long fibrils. Each of the aggregates are formed of PTFE nodes that are connected together by relatively short fibrils. Preferably, the long fibrils have lengths of 500 to 1000 microns and the short fibrils have a lengths of 10 to 30 microns. The aggregates have densities of less than 2.0 grams per cubic centimeter which is lower than the densities of the solid PTFE nodes which have densities of about 2.0 to 2.2 grams per cubic centimeter.