Patents Assigned to Impra, Inc.
  • Patent number: 6264684
    Abstract: Shape memory alloy and elastically self-expanding endoluminal support structures which are at least partially encapsulated in a substantially monolithic expanded polytetrafluoroethylene (“ePTFE”) covering. An endoluminal stent, which has a reduced diametric dimension for endoluminal delivery and a larger in vivo final diametric diameter, is encapsulated in an ePTFE covering which circumferentially covers both the luminal and abluminal walls along at least a portion of the longitudinal extent of the endoluminal stent. The stent and ePTFE covering are helically wound into an open cylindrical configuration with adjacent windings forming overlapping regions of ePTFE covering bonded to one another.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: July 24, 2001
    Assignee: IMPRA, Inc., a subsidiary of C.R. Bard, Inc.
    Inventors: Christopher E. Banas, Tarun J. Edwin, Brendan J. McCrea, Rajagopal R. Kowligi
  • Patent number: 6245099
    Abstract: A method for selectively bonding layers of polymeric material, especially expanded polytetrafluoroethylene (ePTFE), to create endoluminal vascular devices. In a preferred method the selective bonding is achieved by applying pressure to selected areas using a textured mandrel. This permits a stent device to be encapsulated between two layers of ePTFE with unbonded slip pockets to accommodate movement of the structural members of the stent. This allows stent compression with minimal force and promotes a low profile of the compressed device. Unbonded regions of ePTFE allow enhanced cellular penetration for rapid healing and can also contain bioactive substance that will diffuse through the ePTFE to treat the vessel wall.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: June 12, 2001
    Assignee: Impra, Inc.
    Inventors: Tarun J. Edwin, Scott L. Randall, Brendan J. McCrea, Christopher E. Banas
  • Patent number: 6221101
    Abstract: A vascular prosthesis comprising a tube of material other than autologous vascular tissue but considered/approved as safe and supple enough for use instead of such tissue, the tube having an end formation for surgical connection directly to an opening formed in an artery, the end formation serving to promote, at that end and/or within the direct connection and in response to normally pulsed blood flow, localized movement of blood having a non-laminar nature with a shear stress inducing relation to receiving arterial wall.
    Type: Grant
    Filed: October 30, 1998
    Date of Patent: April 24, 2001
    Assignee: IMPRA, Inc.
    Inventors: Peter Lyon Harris, Thien Voon How
  • Patent number: 6214039
    Abstract: A radially expandable endoluminal covered stent assembly and a method and apparatus for making the same. A longitudinally and radially expanded polytetrafluoroethylene tubular graft is circumferentially engaged about one or more radially expandable stents and is retained thereon by a radial recoil force exerted by the tubular graft against the stent. The graft is retained on the stent or stents prior to and during endoluminal delivery and radial expansion without the use of adhesives, sutures or other attachment means. Further, upon radial expansion the stent or stents do not require retaining means for preventing contraction, despite the inherent recoil imparted by the tubular graft. The covered stent is assembled by joining a dilation mandrel and a stent mandrel, placing the graft on the dilation mandrel where it is radially expanded, and passing the expanded graft over the stent that is positioned on the stent mandrel.
    Type: Grant
    Filed: February 18, 1998
    Date of Patent: April 10, 2001
    Assignee: IMPRA, Inc., a subsidiary of C. R. Bard, Inc.
    Inventors: Christopher E. Banas, Rajagopal R. Kowligi, Roy H. Tang
  • Patent number: 6203735
    Abstract: A method of shaping three-dimensional products by manipulating an expanded polytetrafluoroethylene tubular body into a desired three-dimensional conformation. The present invention entails radially expanding a longitudinally expanded polytetrafluoroethylene (ePTFE) tube to form a radially expanded ePTFE (rePTFE) tube, engaging the rePTFE tube circumferentially about a shaping mandrel, heating the assembly to a temperature below the crystalline melt point temperature, or sintering temperature, of polytetrafluoroethylene to radially shrink the diameter of the rePTFE tube into intimate contact with the shaping mandrel, and heating the assembly to a temperature above the crystalline melt point temperature of polytetrafluoroethylene to amorphously lock the microstructure of the shaped polytetrafluoroethylene body.
    Type: Grant
    Filed: February 3, 1997
    Date of Patent: March 20, 2001
    Assignee: Impra, Inc.
    Inventors: Tarun J. Edwin, Scott Randall
  • Patent number: 6190590
    Abstract: A method and apparatus for forming a flanged polytetrafluoroethylene cuffed section from a tubular polytetrafluoroethylene graft. The flanged polytetrafluoroethylene graft is well suited for use as a distal bypass graft, for arteriovenous grafting, or as a hemodialysis access graft. The graft includes an integral terminal polytetrafluoroethylene flanged skirt or cuff section which facilitates an end-to-side anastomosis directly between an artery and the polytetrafluoroethylene flanged graft without need for an intervening venous collar or venous patch.
    Type: Grant
    Filed: August 27, 1998
    Date of Patent: February 20, 2001
    Assignee: Impra, Inc.
    Inventors: Scott Randall, Roy H. Tang, Albert L. Lamay
  • Patent number: 6124523
    Abstract: An encapsulated stent including a stent or structural support layer sandwiched between two biocompatible flexible layers. One preferred embodiment has a stent cover which includes a tubular shaped stent that is concentrically retained between two tubular shaped grafts of expanded polytetrafluoroethylene. Another preferred embodiment has a stent graft which includes at least one stent sandwiched between the ends of two tubular shaped grafts wherein at least a portion of the grafts are unsupported by the stent. Still another embodiment includes an articulating stented graft which includes a plurality of stents spaced apart from one another at a predetermined distance wherein each stent is contained between two elongated biocompatible tubular members. The graft/stent/graft assemblies all have inseparable layers.
    Type: Grant
    Filed: March 10, 1995
    Date of Patent: September 26, 2000
    Assignee: Impra, Inc.
    Inventors: Christopher E. Banas, Tarun J. Edwin
  • Patent number: 6096027
    Abstract: An apparatus for loading a stent onto or into a catheter. A flexible sterile sleeve is provided to encase the stent as it is pulled through a loading device. The loading device is a simple design utilizing a tapered passageway. The passageway has first diameter at a proximal end which tapers to a second diameter, forming a funnel. The passageway continues at the second diameter forming a tube. The sleeved stent is pulled through the loading device from the proximal end to the distal end, smoothly compressing the stent. Depending on the type of stent and catheter being used, the stent is either crimped onto the catheter as it is pulled through the funnel, or is loaded into a catheter positioned at the distal end of the loading device. The sleeve acts to minimize the frictional forces to which the stent is subjected and to eliminate the longitudinal force that the stent would be subjected to if pushed or pulled directly. The sleeve may be close-ended to provide an additional sterility barrier about the stent.
    Type: Grant
    Filed: May 12, 1999
    Date of Patent: August 1, 2000
    Assignee: Impra, Inc., a subsidiary of C.R. Bard, Inc.
    Inventor: Richard Layne
  • Patent number: 6053943
    Abstract: A structurally supported graft (10) having a support structure (26) with strain relief sections (30) contained with an internal surface, an external surface, or a wall thickness of a tubular graft member (12). The structurally supported graft (10) may include a beading element (24) which is co-extruded with the support structure (26) having strain relief sections (30) and spiraled about the tubular graft (10). The support structure (26) includes differing types of strain relief sections (30) which are capable of allowing for the longitudinal and radial expansion of the structurally supported graft (10), respectively. The strain relief sections (30) may also include unconnected ends which form outwardly protruding barbs (62) upon expansion of the structurally supported graft within a blood vessel or body lumen.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: April 25, 2000
    Assignee: Impra, Inc.
    Inventors: Tarun J. Edwin, Christopher E. Banas
  • Patent number: 6039755
    Abstract: Tubular ePTFE materials which are capable of being radially expanded under the influence of a radially outward force applied from the lumen of the ePTFE tubular material to substantially uniformly radially deform the ePTFE material. The ePTFE material is radially expandable to a diameter 700% its unexpanded diameter under the influence of pressures less than 6 atm while retaining the structural integrity of the ePTFE microstructure. Conservation of the structural integrity of the ePTFE material is determined by conservation of the ePTFE microstructure structural integrity.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: March 21, 2000
    Assignee: Impra, Inc., a Division of C.R. Bard, Inc.
    Inventors: Tarun J. Edwin, Fariba Hurry, Christopher E. Banas
  • Patent number: 6004348
    Abstract: An radially expandable stent-graft and method of making the same, including at least one a stent member encapsulated between at least two longitudinally expanded polytetrafluoroethylene (ePTFE) coverings. The at least one stent member has openings through wall surfaces of the stent to permit radial expansion. The at least two longitudinally expanded ePTFE coverings are circumferentially applied over the at least one stent member in their unsintered state, and sintered during application of a circumferential pressure to bond the ePTFE around and through the wall surfaces of the stent. The sintered ePTFE forms a substantially continuous, monolithic and integral encapsulation of the at least one stent. Upon radial expansion of the stent-graft, the stent and the ePTFE node-fibril microstructure radially deform. Radial deformation of the ePTFE encapsulation results in nodal elongation in the axis of radial expansion.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: December 21, 1999
    Assignee: Impra, Inc.
    Inventors: Christopher E. Banas, Tarun J. Edwin, David Dalessandro
  • Patent number: 5935667
    Abstract: A dual porosity PTFE tube including an inner surface of expanded PTFE material having a first porosity and an outer surface of expanded PTFE material having a porosity different from that of the inner surface. The preferred method includes the step of forming inner and outer preformed tubular billets of PTFE resin particles mixed with a lubricant; the outer billet is adapted to closely fit around and concentric to the inner billet. Porosity of the inner and outer surfaces is varied by changing, in the respective billets, the lubrication level and/or the PTFE resin characteristic average particle size. The inner billet is placed inside the outer billet, and the two are extruded together, thereby melding the two billets. The extrudate is then longitudinally expanded and sintered. The inner surface of the resulting PTFE tube exhibits a different porosity than the outer surface of the tube; the porosities of the inner and outer surfaces are both within a range of about 0.10-200 .mu..
    Type: Grant
    Filed: June 10, 1997
    Date of Patent: August 10, 1999
    Assignee: Impra, Inc.
    Inventors: Robert Calcote, Rajagopal R. Kowligi, Stacy Wollner
  • Patent number: 5827327
    Abstract: A carbon containing vascular graft formed of expanded polytetrafluoroethylene and activated carbon admixed with at least a portion of the expanded polytetrafluoroethylene. A bioactive substance may be incorporated in the carbon containing vascular graft.
    Type: Grant
    Filed: January 3, 1997
    Date of Patent: October 27, 1998
    Assignee: IMPRA, Inc.
    Inventors: James M. McHaney, Christopher E. Banas
  • Patent number: 5749880
    Abstract: An radially expandable stent-graft and method of making the same, including at least one a stent member encapsulated between at least two longitudinally expanded polytetrafluoroethylene (ePTFE) coverings. The at least one stent member has openings through wall surfaces of the stent to permit radial expansion. The at least two longitudinally expanded ePTFE coverings are circumferentially applied over the at least one stent member in their unsintered state, and sintered during application of a circumferential pressure to bond the ePTFE around and through the wall surfaces of the stent. The sintered ePTFE forms a substantially continuous, monolithic and integral encapsulation of the at least one stent. Upon radial expansion of the stent-graft, the stent and the ePTFE node-fibril microstructure radially deform. Radial deformation of the ePTFE encapsulation results in nodal elongation in the axis of radial expansion.
    Type: Grant
    Filed: July 27, 1995
    Date of Patent: May 12, 1998
    Assignee: Impra, Inc.
    Inventors: Christopher E. Banas, Tarun J. Edwin
  • Patent number: 5667523
    Abstract: A dual supported intraluminal graft comprising a biocompatible flexible layer sandwiched between two structural support layers. The preferred embodiment comprises a first structural support, such as a stent, which is concentrically retained within a tubular shaped PTFE graft which is concentrically retained within a second structural support, such as a stent. The ends of the PTFE graft may be folded back onto the outer surface of the second structural support thereby forming flaps. Upon radial expansion of the preferred embodiment, the stent/graft/stent assembly forms inseparable layers.
    Type: Grant
    Filed: April 28, 1995
    Date of Patent: September 16, 1997
    Assignee: Impra, Inc.
    Inventors: Anne Nina Bynon, Sandra M. Cundy, Rajagopal R. Kowligi
  • Patent number: 5641443
    Abstract: A dual porosity PTFE tube including an inner surface of expanded PTFE material having a first porosity and an outer surface of expanded PTFE material having a porosity different from that of the inner surface. The preferred method includes the step of forming inner and outer preformed tubular billets of PTFE resin particles mixed with a lubricant; the outer billet is adapted to closely fit around and concentric to the inner billet. Porosity of the inner and outer surfaces is varied by changing, in the respective billets, the lubrication level and/or the PTFE resin characteristic average particle size. The inner billet is placed inside the outer billet, and the two are extruded together, thereby melding the two billets. The extrudate is then longitudinally expanded and sintered. The inner surface of the resulting PTFE tube exhibits a different porosity than the outer surface of the tube; the porosities of the inner and outer surfaces are both within a range of about 0.10-200 .mu..
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: June 24, 1997
    Assignee: Impra, Inc.
    Inventors: Robert Calcote, Rajagopal R. Kowligi, Stacy Wollner
  • Patent number: 5628786
    Abstract: A microporous polytetrafluoroethylene ("PTFE") endovascular graft which has a reinforcing structure integrally bound to the graft which permits radial expansion of the graft and stabilizes the graft against longitudinal compression upon application of an axial force thereto and against axial foreshortening upon radial expansion of the graft. The graft is particularly useful as a covering for an endovascular stent.
    Type: Grant
    Filed: May 12, 1995
    Date of Patent: May 13, 1997
    Assignee: Impra, Inc.
    Inventors: Christopher E. Banas, Scott Randall, Tarun J. Edwin, Fariba Hurry
  • Patent number: 5609624
    Abstract: A microporous reinforced expanded PTFE vascular graft in which the reinforcing structure is substantially identical in porosity to the body of the graft. The graft is characterized by a microporous expanded PTFE tubular graft wall and integral and monolithic expanded PTFE rib structures with a porosity or density substantially identical to that of the tubular graft wall.
    Type: Grant
    Filed: October 8, 1993
    Date of Patent: March 11, 1997
    Assignee: Impra, Inc.
    Inventor: Robert W. Kalis
  • Patent number: 5522882
    Abstract: A stent-graft delivery system which includes a catheter, an expandable balloon having non-tapered ends positioned near the distal end of the catheter, a stent circumferentially positioned around a center of the balloon, and a graft circumferentially positioned around the stent. The balloon configuration comprising non-tapered ends may be achieved by 1) preforming the balloon to the desired geometry which comprises substantially non-tapered ends; 2) positioning a non-compliant sheath over each of the ends of an existing balloon having tapered ends, or 3) invertedly attaching the first and second ends of a compliant tubular member to the catheter to form the desired balloon configuration. The desired balloon configuration is a balloon geometry which uniformly conforms to the geometry of the stent-graft assembly. A method for introducing the stent-graft delivery system into a blood vessel are also disclosed.
    Type: Grant
    Filed: October 21, 1994
    Date of Patent: June 4, 1996
    Assignee: Impra, Inc.
    Inventors: Mark T. Gaterud, Rajagopal R. Kowligi, Fariba Khalilifard, Christopher E. Banas
  • Patent number: 5512229
    Abstract: An apparatus and process for expanding polymer films such as PTFE films includes gripping the unexpanded film about its periphery with a number of symmetrically disposed gripping members each equidistant from the center of the film. The gripping members are simultaneously rotated through an arc away from the center of the film, as by pivotally securing each gripping member to the end of an associated expansion arm and rotating the end of each expansion arm away from the center of the film while maintaining the gripping members equidistant from the center of the film. The expansion arms are uniformly rotated by a geared shaft powered by a drive mechanism that extends through the wall of an oven for coupling to an external motor. Also disclosed is an expanded PTFE film made in accordance with such process.
    Type: Grant
    Filed: May 25, 1994
    Date of Patent: April 30, 1996
    Assignee: Impra, Inc.
    Inventors: Charles F. Bosse, Rajagopal R. Kowligi