Abstract: A method of forming porous articles with a varying pore distribution by extrusion from a billet with a varying lubricant distribution. A single-polymer polytetrafluoroethylene is extruded and then stretched and sintered to provide a differential porous PTFE structure composed of fibers and nodes connected to one another by these fibers. The microfibrous structure has a portion within the cross-section that possesses a different pore size, accompanied by a different node and fiber geometry, than adjacent areas within that cross section. In a vascular graft, the pores taper inwardly, providing a fluid-tight lumen wall structure that prevents leakage, yet promotes cellular ingrowth and natural tissue regeneration. A node structure of radially-oriented plates provides flexibility, suture strength, and enhanced protection against collapse.

Abstract: A vascular endoprosthesis is formed of a tubular liner preform with a continuous surface and having a diameter smaller than that of an intended vessel. The liner is inserted to a treatment site, and its sheet material undergoes a radially-directed expansion to a final size that fits the vessel. Insertion and in situ expansion are achieved using a catheter assembly in which either an internal stent, such as a stiff-filament helically woven tube, or an inflatable balloon urge the liner preform outwardly against the inner wall of the vessel. The stent, or one or more simple internal snap-rings anchor the expanded liner in place. The expanded liner is porous, or becomes more porous during expansion, and one or more aspects of its porosity are tailored to the intended treatment goal of immobilizing treatment material, isolating cells, or permitting controlled permeation of selected materials.

Abstract: A porous tube suitable for use as a vascular graft prosthesis and a method of making it is disclosed. It has a structure of porous polytetrafluoroethylene having a fibrous structure of nodes and fibers connecting the nodes together and an integrated intrawall circumferential support adjacent to areas of variable porosity. This invention provides a polytetrafluoroethylene polymer in a porous form useful as artificial internal organs for, for example vascular bypass, vascular access, and endovascular prosthesis. PTFE walls with radial zones of differing porosity are described.

Abstract: A method of forming porous articles with a varying pore distribution by extrusion from a billet with a varying lubricant distribution. A single-polymer polytetrafluoroethylene is extruded and then stretched and sintered to provide a differential porous PTFE structure composed of fibers and nodes connected to one another by these fibers. The microfibrous structure has a portion within the cross-section that possesses a different pore size, accompanied by a different node and fiber geometry, than adjacent areas within that cross section. In a vascular graft, the pores taper inwardly, providing a fluid-tight lumen wall structure that prevents leakage, yet promotes cellular ingrowth and natural tissue regeneration. A node structure of radially-oriented plates provides flexibility, suture strength, and enhanced protection against collapse.

Abstract: The wall of a prosthesis has a region which modulates communication through the porosity of the wall. The prosthesis is unitary, but may be assembled in successive bodies which are coalesced, so that the porous microstructure changes distinctly at stages through the thickness dimension of the wall. One embodiment is formed entirely of fluoropolymer, and has at least one surface adapted to support tissue regeneration and ingrowth. The modulation region is a stratum of high water entry pressure that reduces pulsatile hydraulic pressure transmission, or locally alters fluid-born-distribution of biological material through the wall and allows more natural gradients for tissue regeneration and growth in the outer region of the wall.

Abstract: A process for producing a shaped porous article includes the steps of providing an extrudate of a fluoropolymer material which is capable of being stretched and bilaterally stretching the extrudate along a longitudinal axis. The stretching step is carried out under conditions sufficient to yield an article which is substantially uniformly stretched over a major portion of its length. After stretching, the material has a unique through-pore microstructure characterized by elongate nodes connected by fibrils. The stretched material is sintered while being maintained in its stretched state to produce the shaped porous article. A significant feature of the inventive process is that stretching is carried out by displacing both ends of the extruded material as opposed to known method wherein only one end of an extruded material is stretched, resulting in a microporous fluoropolymer article which are different than conventional fluoropolymer stretching/expansion processes.

Abstract: A method of forming porous articles with a varying pore distribution by extrusion from a billet with a varying lubricant distribution. A single-polymer polytetrafluoroethylene is extruded and then stretched and sintered to provide a differential porous PTFE structure composed of fibers and nodes connected to one another by these fibers. The microfibrous structure has a portion within the cross-section that possesses a different pore size, accompanied by a different node and fiber geometry, than adjacent areas within that cross section. In a vascular graft, the pores taper inwardly, providing a fluid-tight lumen wall structure that prevents leakage, yet promotes cellular ingrowth and natural tissue regeneration. A node structure of radially-oriented plates provides flexibility, suture strength, and enhanced protection against collapse.

Abstract: An implantable prosthetic device for sustained release of a bioactive material into a fluid flow pathway of a patient comprises a body adapted for attachment to the fluid flow pathway. The body defines a primary lumen for accommodating fluid flow therethrough and at least one secondary lumen at least a portion of which is separated from the primary lumen by a wall sufficiently permeable to permit a bioactive material disposed in the lumen to diffuse through the wall and into the primary lumen. The bioactive material can be either a therapeutic or diagnostic agent. In a particular embodiment of the invention, the device comprises a tubular body consisting of stretched and/or expanded polytetrafluoroethylene and is adapted for attachment to a blood vessel of a patient.

Abstract: A polylumenal implantable device comprises a body defining a plurality of capillary lumina. The prosthetic device is suitable for implantation in a patient as an arterial or venous bypass graft or shunt, or intra-organ implant as well as other purposes. The improved prosthetic device has increased surface area and preferably a three-dimensional porosity for encouraging the harboring of, for example, endothelial cells, as well as for receiving organized deposition of material such as genetically enhanced cell types. A method for providing a bioactive material to a patient includes the steps of providing a polyluminal implantable organ comprising an implantable body defining a plurality of capillary lumina, treating the interior surfaces of the lumina with a bioactive material or plasma polymerization, and implanting the prosthetic device in the patient so that bodily fluids of the patient come into contact with the treated interior surfaces.

Abstract: An implantable prosthetic device comprises a remotely detectible component disposed in the body forming the device for allowing the device to be detected by x-ray, ultrasonic, or MRI imaging. By disposing at least two remotely detectible components in the body of the device, the effective flow diameter provided by the device can be monitored. A method for monitoring a patient having a damaged or dysfunctional vascular pathway includes the steps of implanting in the patient the disclosed prosthetic device and monitoring the patency of the device by x-ray, ultrasonic, MRI, or other form of remote imaging.

Abstract: A vascular prosthesis has a plurality of tubular structures, each of which is manually separable from the others. Each tube structure has a biocompatible exterior surface and a lumen of predetermine diameter. Fluid, such as blood, is channelled through the lumina upon implantation in an arterial or venous pathway. Each of the tube structures is separable from the others over at least a portion of the axial extent of the exterior surface.

Abstract: An implantable self-sealing vascular graft device comprises an implantable tubular body defining a primary lumen and at least one secondary lumen, the lumina sharing a common side wall. The primary lumen is adapted for attachment to the vascular system of the patient to accommodate blood flow therethrough. A non-biodegradable elastomeric material disposed in the secondary lumen permits repeated self-sealing penetrations of a cannula through the elastomeric material and into the primary lumen. A method for repeatedly accessing a patient's vascular system by implanting in the patient the disclosed structure and accessing a patient's vascular system by passing a cannula through the secondary lumen, the common side wall, and into the primary lumen is also disclosed.