Abstract: The present invention provides tissue equivalent scaffold structures and methods of production thereof. Such methods include providing a casting chamber comprising an elongate mould portion, axially disposing a lumen template within the elongate mould portion, and at least partly filling the casting chamber with a gel casting material comprising a matrix of fibrils or fibres and an interstitial fluid phase, such that a portion of the lumen template extends above the casting material. The fluid phase of the gel is allow to flow axially out of the elongate mould portion, in a restricted manner, thereby resulting in axial densification of the gel casting material to form a tissue equivalent tubular scaffold. Tissue equivalent scaffold structures according to the present invention are able to support cell populations both within the walls and on the surface of the construct.

Abstract: A medical system including a tube defining a lumen, a porous body connected to a distal end of the tube to be advanced to a target site within a subject. The porous body defines a plurality of openings, the plurality of openings are in fluid connection with the lumen, the porous body includes a first material and a second material, and the second material elutes from the porous body in the subject.

Abstract: The invention relates to a device for testing the functioning of an aortic valve by placing the device on the free end of a cylindrical tubular prosthesis inserted into the aorta, said tubular prosthesis being connected, with its other end, to the aortic wall in the region of the aortic valve. According to the invention, the device consists of a multi-part housing provided with at least one through-flow channel for a control liquid, the housing being provided, on its lower side facing the free end of the tubular prosthesis, with a peripheral sealing device that can be placed around the edge of the tubular prosthesis, and at least one pressure-measuring sensor and at least one optical sensor element for video recording being arranged on the lower side.

Abstract: A method for passivating a biomaterial surface includes modifying proteinaceous material disposed at the biomaterial surface. The passivation may be effectuated by exposing the biomaterial surface to therapeutic electrical energy in the presence of blood or plasma.

Abstract: A stent for placement in a body lumen is fabricated by forming a tube having an un-deployed diameter sized for the tube to be placed on a deployment balloon and advanced through a body lumen to a deployment site. The tube is expandable upon inflation of the balloon to an enlarged diameter sized for the tube to be retained within the lumen at the site upon deflation and withdrawal of the balloon. The tube has a stent axis extending between first and second axial ends of the tube. The tube has an exterior surface and an interior surface. The tube is polished to polish the exterior surface to a smooth surface finish and with at least a portion of the interior surface having a rough surface finish rougher than the surface finish of the exterior surface.

Abstract: A method of removing slag formed during laser cutting a hypotube may include flowing cooling gas into a laser nozzle, directing flow of the cooling gas onto an external surface of the hypotube, and injecting cooling fluid into an inner lumen of the hypotube at a velocity. Flowing the cooling gas and injecting the cooling fluid may at least partially remove slag from the external surface of the hypotube.

Abstract: Systems and methods are provided for controlling the diameter of a mammalian hybrid coronary bypass graft. The system includes a controller having at least one input for receiving information and feedback information and an output for outputting control signals, including at least one steady flow system control signal; and a pressure/flow loop subsystem coupled to the controller. The pressure/flow loop subsystem includes a specimen holder, an external flow loop system coupled to the specimen holder, a steady flow system, and an output for outputting the feedback information. The pressure/flow loop subsystem receives the control signals and is capable of adjusting a diameter of a specimen in accordance with the control signals, when the specimen holder contains the specimen.

Abstract: Developing heart valves are exposed to dynamic strains by applying a dynamic pressure difference over the leaflets. The flow is kept to a minimum, serving only as a perfusion system, supplying the developing tissue with fresh nutrients. Standard heart valves were engineered based on B trileaflet scaffolds seeded with cells isolated from the human saphenous vein. Tissue compaction is constrained by the stent, inducing increasing pre-strain in the tissue. The dynamic strains the tissues are exposed to via the dynamic pressure difference, are estimated using finite element methods based on the mechanical properties of the neo-tissue, in order to get inside into the strain distribution over the leaflet.

Abstract: An organ support apparatus includes: (a) a fluid circuit defining upstream and downstream legs adapted to be connected to an organ to be supported; (b) a circulation pump connected to the fluid circuit for circulating a process fluid through the fluid circuit and the organ; and (c) a first waveform generator connected to the fluid circuit for impressing a preselected pressure waveform on the process fluid.

Abstract: A system for hemodynamic simulation comprises a vessel having properties of a blood vessel, a reservoir containing a quantity of fluid, tubing connecting the vessel and reservoir, and at least one pump for circulating the fluid within the system. Fluid can be tissue culture medium or blood analog fluid, and the vessel may include mammalian cells attached to its inside. A drive system, comprising two reciprocating drive shafts that are coupled by a cam, enables the uncoupling of pulsatile flow and pulsatile pressure to provide independent control over wall shear stress and circumferential strain. The shaft drives two pumps that are 180 degrees out-of-phase and are connected upstream and downstream of the vessel, and effect this uncoupling.

Abstract: Hybrid synthetic grafts and embodiments of systems and methods for producing hybrid vascular grafts that can yield implantable grafts that combine synthetic grafts with living cells. Embodiments of systems can include a pressure/flow loop subsystem having an external flow loop system coupled to a specimen holder, where the pressure/flow loop subsystem is capable of adjusting at least two dynamic conditions in the specimen holder or a diameter of a specimen in the specimen holder. Embodiments of methods can coat a hybrid graft with a confluent monolayer of endothelial cells by immobilizing stem cells on a hybrid hemodialysis access graft or a hybrid femoral artery bypass graft, and placing the hybrid graft in a system embodiment according to the invention under conditions effective to promote the stem cells to form a confluent monolayer on the hybrid graft and in an environment to promote the stem cells to differentiate into endothelial cells.

Abstract: Hybrid synthetic grafts and embodiments of systems and methods for producing hybrid vascular grafts that can yield implantable grafts that combine synthetic grafts with living cells. Embodiments of systems can include a pressure/flow loop subsystem having an external flow loop system coupled to a specimen holder, where the pressure/flow loop subsystem is capable of adjusting at least two dynamic conditions in the specimen holder or a diameter of a specimen in the specimen holder. Embodiments of methods can promote endothelialization of a hybrid hemodialysis access graft or a hybrid femoral artery bypass graft by placing the hybrid hemodialysis access graft or the hybrid femoral artery bypass graft in a system embodiment according to the invention under conditions effective to promote endothelial cells to form a confluent monolayer on the surface of the hybrid graft.

Abstract: Hybrid synthetic grafts and embodiments of systems and methods for producing hybrid vascular grafts that can yield implantable grafts that combine synthetic grafts with living cells. Embodiments of systems can include a pressure/flow loop subsystem having an external flow loop system coupled to a specimen holder, where the pressure/flow loop subsystem is capable of adjusting at least two dynamic conditions in the specimen holder or a diameter of a specimen in the specimen holder. Embodiments of methods can promote endothelialization of a hybrid hemodialysis access graft or a hybrid femoral artery bypass graft by placing the hybrid hemodialysis access graft or the hybrid femoral artery bypass graft in a system embodiment according to the invention under conditions effective to promote stem cells to form a confluent monolayer on the hybrid graft.

Abstract: A method of yielding a functional human hybrid coronary bypass graft is provided. The method includes conditioning a hybrid synthetic tubular structure having stem cells and/or endothelial cells on at least one surface to yield the functional human hybrid coronary bypass graft. Specifically, the method includes placing the hybrid synthetic tubular structure in a system capable of producing three dimensional dynamic conditions for a sufficient time to yield said functional human hybrid coronary bypass graft.

Abstract: A method of yielding a functional human hybrid hemodialysis access graft is provided. The method includes conditioning a hybrid synthetic tubular structure having stem cells and/or endothelial cells on at least one surface to yield the functional human hybrid hemodialysis access graft. Specifically, the method includes placing the hybrid synthetic tubular structure in a system capable of producing three dimensional dynamic conditions for a sufficient time to yield said functional human hybrid hemodialysis access graft.

Abstract: A bioreactor and a method for growing engineered tissue provide facing surfaces in a vessel for containing cell-culture media. The facing surfaces are equidistant and define a gap therebetween while providing substrates for cell tissue growth. By maintaining conditions within the vessel conducive to cell tissue growth and moving the surfaces relative to one another within such cell culture media, tissue growing thereupon is subjected to physiological flow and shear stress, preferably through the use of oscillating motion, and engineered tissue is produced.

Abstract: A biocompatible material having excellent biocompatibility such as small interaction with a component of a living body such as a protein or blood cell. A biocompatible material comprising a polymer obtained by polymerizing a monomer composition comprising an amino acid-type betaine monomer represented by the formula (I): wherein R1 is a hydrogen atom or a methyl group; R2 is an alkylene group having 1 to 6 carbon atoms; each of R3 and R4 is independently an alkyl group having 1 to 4 carbon atoms; R5 is an alkylene group having 1 to 4 carbon atoms; and Z is an oxygen atom or an —NH group; and a polymerizable monomer represented by the formula (II): wherein R1 is as defined above; and R6 is a monovalent organic group, in a weight ratio, i.e. amino acid-type betaine monomer/polymerizable monomer, of from 1/99 to 100/1. The biocompatible material can be suitably used, for example, in food, a food additive, a medicament, a quasi-drug, a medical device, cosmetics, a toiletry article, or the like.

Abstract: Described are medical devices which are or can be used to form tubular medical devices, and related methods. Preferred devices include tubular grafts of biomaterial having lumen walls which present no seam edge that traverses the entire length of the lumen, illustratively including devices having lumen walls which have a discontinuous seam presenting multiple seam edges. Such a device may include a tubular structure formed by inserting a plurality of extensions of a biomaterial sheet through a plurality of corresponding apertures of the sheet.

Abstract: An improved method and devices for preventing restenosis are provided. The method may include delivering a stent configured to contain a stenosis to a body vessel. The method may also include using atherectomy at the site prior to stent delivery. In one embodiment, the stent has a proximal end, a distal end, and a center portion arranged such that the diameters of the proximal and distal ends are greater than the diameter of the center portion. In one embodiment, the atherectomy device includes a housing to prevent injury to the unaffected areas of the body vessels but the cutter is extendible beyond the housing. In one embodiment, the stent may be impregnated with at least one drug after stent deployment.

Abstract: A microprocessor controlled and instrumented bioreactor for conditioning intravascular tissue engineered medical products. One bioreactor design including an integrated pump to provide a relatively small volume of fluid nutrient. The microprocessor control providing measurement and control of the fluid flow and tissue displacement and subsequent determination of material properties. One design includes a flexible joint providing motion of the treated tissue in the axial, bending and torsional direction.

Abstract: An apparatus for tacking a multi-lumen tubular assembly together comprises a laser, an optical member and a placement tray for retaining the tubular assembly. A portion of the optical member defines a window that is substantially transparent to laser energy emitted from the laser. The window has a substantially concave shaped surface. The placement tray and the window surface define a processing area for positioning at least a portion of the tubular assembly. The processing area receives the laser energy that is emitted from the laser and passed through the window of the optical member. The tubular assembly is defined by an outer tubular member disposed about at least a portion of at least one inner tubular member. The laser energy transmitted into the processing area is transmitted substantially through the outer tubular member and is substantially absorbed by at least one region of the least one inner tubular member.

Abstract: Treatment with magnesium produces a inhibition of acute stent thrombosis under high-shear flow conditions without any hemostatic or significant hemodynamic complications.

Abstract: A crosslinkable macromer system and related methods of preparing the system and using the system in the form of a crosslinked matrix between a tissue site and an implant article such as a tissue implant or on the porous surface of a prosthetic device. The macromer system includes two or more polymer-pendent polymerizable groups and one or more initiator groups (e.g., polymer-pendent initiator groups). The polymerizable groups and the initiator group(s), when polymer-pendent, can be pendent on the same or different polymeric backbones. The macromer system provides advantages over the use of polymerizable macromers and separate, low molecular weight initiators, including advantages with respect to such properties as nontoxicity, efficiency, and solubility. A macromer system of the invention can be used as an interface between the tissue site and implant article in a manner sufficient to permit tissue growth through the crosslinked matrix and between the tissue site and implant.

Abstract: An implantable stent is coated with a material that attracts heparin and with which heparin forms a bond. The stent is exposed to a heparin containing solution just prior to implantation or is first implanted and then exposed to heparinized blood. As heparin becomes detached from the stent, the implantation site is exposed to heparin to restore an effective level and thereby prevent thrombosis.

Abstract: A system for hemodynamic simulation comprises a vessel having properties of a blood vessel, a reservoir containing a quantity of fluid, tubing connecting the vessel and reservoir, and at least one pump for circulating the fluid within the system. Fluid can be tissue culture medium or blood analog fluid, and the vessel may include mammalian cells attached to its inside. A drive system, comprising two reciprocating drive shafts that are coupled by a cam, enables the uncoupling of pulsatile flow and pulsatile pressure to provide independent control over wall shear stress and circumferential strain. The shaft drives two pumps that are 180 degrees out-of-phase and are connected upstream and downstream of the vessel, and effect this uncoupling.

Abstract: This invention relates to methods of coating the lumenal surface of a blood vessel, or other tissue cavity, and to compositions suitable for use in same.

Abstract: In accordance with embodiments of the present invention, a method for preparing a shape memory alloy endoprosthesis, displaying strain induced martensite phenomenon, for delivery includes inserting a shape memory alloy endoprosthesis into a delivery device, inducing a first strain within a first region of the shape memory alloy endoprosthesis, inducing a second strain within a second region of the shape memory alloy endoprosthesis, and sterilizing the delivery device while maintaining the first strain and the second strain induced within the shape memory alloy endoprosthesis. In accordance with other embodiments of the present invention, an apparatus for delivering a shape memory alloy endoprosthesis includes an inner core having a first diameter, an outer body having a second diameter greater than the first diameter, and a calibrated endcap attached to the inner core.

Abstract: A graft provided with a flexible sealing member to substantially prevent blood from leaking between the graft a lumen into which the graft is placed. In one embodiment, the flexible sealing member may be pressed against the vascular wall by an outwardly biased spring means attached to the sealing member. In other embodiments, the sealing member may be self-positioning upon deployment of the graft. The sealing member also may be formed into the shape of a toroid, which may be filled with thrombogenic material causing blood permeating into the toroid-shaped space to coagulate therein and hold the sealing member in place. It is also contemplated that the sealing member be formed from tufts of frayed yarn protruding circumferentially from the outer surface of the graft. A method of manufacturing such tufted yarn sealing members is also disclosed.

Abstract: An implanted device such as a stent is provided which is capable of holding an induced charge or sufficient magnitude that the device may, by electrostatic means, attract the bioactive material to itself. The charge, either positive or negative, or relative to the bioactive material sufficiently positive or negative, is deposited into the implantable device via an exterior induction coil. The implantable device itself becomes an introduced “dosage form”, becoming part of a biologically closed electric circuit, through which the bioactive material is attracted to the implanted device.

Abstract: Treatment with magnesium produces a inhibition of acute stent thrombosis under high-shear flow conditions without any hemostatic or significant hemodynamic complications.

Abstract: A method for delivering heparin, wherein an implantable stent is coated with a material that attracts heparin and with which heparin forms a bond. The stent is exposed to a heparin containing solution just prior to implantation or is first implanted and then exposed to heparinized blood. As heparin becomes detached from the stent, the implantation site is exposed to heparin to restore an effective level and thereby prevent thrombosis.

Abstract: A glycocalyx-like material is applied to a stent in order to mimic the outer surface of the cells lining arteries and veins to prevent thrombogenesis. The glycocalyx material is applied over a base layer of a fluorocarbon that is applied directly to the stent surfaces.

Abstract: A method for polishing radially expandable surgical stents is disclosed where fluid abrasive media M flows over surfaces of the stent 10 causing the surfaces of the stent 10 to be polished and streamlined. The stent 10 is temporarily provided with cylindrical support ends 20, which are not radially expandable to support the stent 10 during the polishing process. An interior polishing fixture 100 is provided which has cylindrical chambers 135 therein adapted to receive a stent 10 therein. Fluid abrasive media M then flows into bores 108 in the fixture 100 leading to the cylindrical chambers 135 and adjacent the inner diameter surfaces of the stent 10. Surfaces of the stent 10 forming the outer diameter are polished by placing the stent 10 within an exterior polishing fixture 200 which has a cylindrical recess 220 therein.

Abstract: A device for exploration of the cardiovascular system of human or animal bodies includes a generally transparent blind tube delimiting a cavity in which can be disposed an optical display device, the open end of the tube being shaped to be ensleeved axially in a sealed manner in the passage of an artery or of a vein having first been at least partially sectioned such that the cavity of the tube in the interior of the artery or of the vein form a common chamber at least partially closeable by a cardiac valve. The tube, maintained in ensleeved position by a suitable securement member, includes at least one supplemental opening for the introduction into the cavity of the tube of a physiological liquid under pressure.

Abstract: The invention provides a device and process for recellularizing essentially acellular or devitalized tissue grafts, including for example essentially acellular or devitalized vascular tissue grafts, derived from human or animal sources, or as constructed using any number of tissue engineering methodologies. The process includes repopulating and reendothelializing an essentially acellular or devitalized tissue graft. The device is useful for producing a repopulated tissue graft from an essentially acellular or devitalized tissue, as well as for producing an essentially acellular or devitalized tissue graft.

Abstract: A crosslinkable macromer system and related methods of preparing the system and using the system in the form of a crosslinked matrix between a tissue site and an implant article such as a tissue implant or on the porous surface of a prosthetic device. The macromer system includes two or more polymer-pendent polymerizable groups and one or more initiator groups (e.g., polymer-pendent initiator groups). The polymerizable groups and the initiator group(s), when polymer-pendent, can be pendent on the same or different polymeric backbones. The macromer system provides advantages over the use of polymerizable macromers and separate, low molecular weight initiators, including advantages with respect to such properties as nontoxicity, efficiency, and solubility. A macromer system of the invention can be used as an interface between the tissue site and implant article in a manner sufficient to permit tissue growth through the crosslinked matrix and between the tissue site and implant.

Abstract: An apparatus is disclosed for differentially treating a medical device. One portion of the device is treated with a first fluid and a separate portion is treated with a second fluid. The second fluid generally is substantially different from the first fluid. The first fluid can be contacted with an flow region of the medical device. The apparatus can include a conduit system, where fluid flowing through the conduit system flows through the flow region. Sheet material can be treated differentially on the opposite surfaces of the sheet. The medical device can include vascular tissue.

Abstract: A stent for placement in a body lumen is fabricated by forming a tube having an un-deployed diameter sized for the tube to be placed on a deployment balloon and advanced through a body lumen to a deployment site. The tube is expandable upon inflation of the balloon to an enlarged diameter sized for the tube to be retained within the lumen at the site upon deflation and withdrawal of the balloon. The tube has a stent axis extending between first and second axial ends of the tube. The tube has an exterior surface and an interior surface. The tube is polished to polish the exterior surface to a smooth surface finish and with at least a portion of the interior surface having a rough surface finish rougher than the surface finish of the exterior surface.

Abstract: A heparin-collagen dispersion is provided for impregnating a vascular prosthesis with heparin and collagen. The dispersion is prepared at an alkaline pH to allow the addition of heparin without causing the agglutination of collagen from the dispersion. The impregnation of collagen and heparin within the prosthesis effectively prevents blood loss and thrombus formation after implantation of the prosthesis.