Abstract: Methods for treating glutaraldehyde-fixed collagenous tissues to mitigate there propensity for subsequent calcification and to improve durability. Collagenous tissues which have been harvested and cross-linked by glutaraldehyde are exposed to a carboxyl activating agent to convert the free carboxyl (COOH) groups of the collagen molecules to activated carboxyl moieties (e.g., o-acylisourea). Thereafter, the collagenous tissue is exposed to a compound capable of reacting with the activated carboxyl moieties (e.g., o-acylisourea) to form non-carboxyl side groups. Monofunctional and multifunctional amines are examples of compounds which may be utilized to react with the activated carboxyl moieties to form such non-carboxyl side groups. Thereafter, the collagenous tissue is again exposed to glutaraldehyde. If the non-carboxyl side groups have functional amino groups (NH.sub.

Abstract: A method for treating fixed biological tissue inhibits calcification of the biological tissue following implantation thereof in a mammalian body. The method includes placing the biological tissue in contact with a treatment solution, inducing relative tissue/solution movement, and heating the solution. The relative movement may be induced by shaking a container in which the tissue is immersed in the treatment solution, or by stirring the solution within the container. The movement may also be induced by flowing a treatment solution past the tissue to be treated. The tissue may be free to move in the treatment container, or may be restrained from gross movements. The flow may be part of a circulation system having a reservoir, with a heater being provided to heat the treatment solution in the reservoir. Alternatively, a treatment apparatus, including a fluid circulation system if desired, may be enclosed in an incubator.

Abstract: Improved, adaptable tissue-type heart valves and methods for their manufacture are disclosed wherein a dimensionally stable, pre-aligned tissue leaflet subassembly is formed and its peripheral edge clamped between and attached to an upper shaped wireform and a lower support stent. A variety of adaptable structural interfaces including suture rings, flanges, and conduits may be attached to the support stent with or without an outlet conduit disposed about the wireform to provide a tissue-type heart valve adaptable for use in either a natural heart or in mechanical pumping devices.

Abstract: Stented tubular grafts of expanded, sintered polytetrafluoroethylene (PTFE). The stented PTFE grafts of the present invention include an integrally stented embodiment, an externally stented embodiment, and an internally stented embodiment. In each embodiment, the stent may be either self-expanding or pressure-expandable. Also, in each embodiment, the stent may be coated or covered with a plastic material capable of being affixed (e.g., heat fused) to PTFE. Manufacturing methods are also disclosed by the individual components of the stented grafts are preassembled on a mandrel and are subsequently heated to facilitate attachment of the PTFE layer(s) to one another and/or to the stent. Optionally, the stented graft may be post-flexed and post-expanded following it's removal from the mandrel to ensure that the stented graft will be freely radially expandable and/or radially contractible over it's full intended range of diameters.

Abstract: An in vitro tissue testing system especially useful for testing blood/tissue interactions. The system includes a tissue holding frame which forms a chamber between two flat pieces of tissue with a spacer plate therebetween. The spacer plate includes a reservoir aperture bordered on both sides by the opposed tissue pieces, and a mechanism for depressing portions of the tissue pieces inwardly into the chamber to propel blood from one side of the chamber to the other. The flow created simulates actual blood flow in a host system. The reservoir aperture may be hourglass shaped with circular end portions and a middle blood passageway. The actuating mechanism may include pistons for alternating contact with the tissue within the confines of the opposite reservoir end portions, thus propelling blood from one end portion to the other. The pistons may be driven by a plurality of eccentric cams on shafts coupled to a common drive motor.

Abstract: Methods for binding heparin to biological or synthetic materials which are to be implanted within a mammalian body. In instances where connective tissue proteins or other components of the material having adequate carboxyl groups present thereon, the method comprises a) contacting the material with a carboxyl-activating agent, b) contacting the material with a polyamine compound to form amide-bound polyarnine side chains at the sites of the previously activated carboxyl groups, and c) contacting the material with heparin such that heparin will become bound to the amino groups on the polyamine side chains.

Abstract: The distensible annuloplasy ring which may be enlarged, in situ, by application of dilatory pressure by way of a balloon or other dilating apparatus. The distensible annuloplasy ring of the invention is usable in pediatric patients whose growth, subsequent to surgical implantation of the ring, will necessitate subsequent enlargement of the ring to accommodate growth of the annulus. The invention includes a transluminal and/or transeptal method for post-implantation enlargement of the annuloplasty ring via catheter.

Abstract: A continuous cardiac output monitor a general-purpose monitoring console with local display and communication facilities, and a module removably interfacing with the console to configure the latter for performing continuous cardiac output monitoring. The module includes a switch-mode high efficiency power amplifier for providing electrical heating power at a selected voltage, frequency, and wave form to a heating element of a continuous cardiac output monitoring catheter, which catheter at a distal end portion thereof is immersed in the blood flow of a patient. The catheter effects a temperature transient in the patient's blood flow by the controlled application of electrical resistance heating utilizing electrical power from the power amplifier, and this temperature transient is sensed and used to derive a value for the patient's cardiac output.

Abstract: A magnetically-driven centrifugal blood pump includes a housing and an impeller mounted for rotation within. The impeller includes a generally disk-shaped base plate and a plurality of curvilinear vanes extending axially upward therefrom. The vanes project radially outward from the base plate approximately one-third of their curvilinear length. The housing includes a rear wall spaced from the impeller base plate across a constant gap, with a sloped transition wall surrounding the rear wall and joining it to a peripheral wall. A tangential outlet is provided in the peripheral wall. A front wall extends inward from the peripheral wall with a slight conicity to an axial inlet. The vanes each have a front edge which slopes away from the front wall in the radially outward direction to provide a widening gap therebetween. The vanes have inner ends which together define a vane-free inner region below and slightly larger than the inlet.

Abstract: A bileaflet mechanical cardiovascular valve having a generally annular valve body and two occluder leaflets mounted within the valve body such that the occluder leaflets will move back and forth between an open configuration wherein blood is permitted to flow through the annular valve body and a closed configuration wherein blood is prevented from flowing in at least one direction through the annular valve body. Slots formed in opposite ends of the occluder leaflets are mounted upon raised mounting members formed on the inner surface of the annular valve body to facilitate the opening and closing movement of the occluder leaflets.

Abstract: A storage and dispensing apparatus for a springy guide wire used in medical procedures includes a coiled tubular portion defined by elongate tubing with a bore for receiving the guide wire. A ring section includes a tangential portion of the tubing defining an open end from which the guide wire may be dispensed. Adjacent to the tangential portion, the tubing defines a pair of spaced apart openings from which the guide wire respectively exits and reenters the tubing. Intermediate the pair of openings the tubing defines a curved external surface across which the guide wire runs externally of the tubing and is manually accessible for advancing and retracting movements impelled by a user's thumb, for example. The guide wire defines a pair of gentle S-shaped bends adjacent to the ends of the externally-exposed curved section, which bends cause the guide wire to engage sufficiently with the storage and dispensing apparatus to resist self-ejection.

Abstract: A method for improving the radial enlargeability and other properties of tape-reinforced tubular vascular graft formed of sintered fluoropolymer(s), such as expanded, sintered PTFE. Broadly, the method comprises the step of radially shrinking the reinforcement tape layer of the graft, or the entire tape-reinforced graft, after sintering thereof. Such radial shrinkage of the reinforcement tape layer, or of the entire graft, renders the graft subsequently radially enlargeable by more than 5%, without tearing or breaking of the reinforcement tape layer of the graft. Radially enlargeable grafts of the present invention may be combined with various types of stents or anchoring systems, to form endovascular graft devices which are transluminally insertable and implantable within the lumen of a host blood vessel.

Abstract: A guide wire dispenser which is used to introduce a guide wire into the body using one hand. The dispenser utilizes a trigger grip configuration which is arranged in combination with a thumb access platform to provide accurate single-handed control of guide wire delivery to the body. A dual trigger configuration is also disclosed which provides the capability to dispense a guide wire from two different nozzles in a single device.

Abstract: A prosthetic mechanical valve includes a base portion defining a through blood flow pathway closed by at least a pair of valve leaflets. The valve leaflets are pivotally carried by the base portion and movable in response to dynamic blood fluid pressures between a first position at which the leaflets close blood flow through the pathway and a second open position allowing blood flow in the pathway. A pair of confronting magnets are carried one to each of the pair of valve leaflets and attract one another. The magnetic forces of attraction between the pair of magnets imparts a biasing torque to the valve leaflets which tends to synchronize pivotal movements of the leaflets, cushions their sealing contact, quiets valve operation, and biases the leaflets toward a third partially open position. As a result, under conditions of nearly balanced blood fluid pressures across the pair of valve leaflet they anticipatorily open toward their third position to improve pumping effectiveness.

Abstract: A ventricular assist device includes a pair of valved conduits and a pumping portion connected by these conduits into the circulatory system of a host patient. The pumping portion and valved conduits are constructed and configured to minimize the number of material-surface transitions which blood must cross in flowing through the device. Also, the valved conduits include porcine xenograft valves, which are externally supported by stenting structure located outside of the blood-contacting flow path of the device. A flexible shape-retaining inner wall member of the valved conduits is impervious to blood, but defines a porous inner surface on which a stable biological interface may form. Also, this inner wall member is shaped with sinuses which do not replicate either the porcine sinuses from which the xenograft valves were taken, or human aortic sinuses.

Abstract: A female electrical connector (164') is carried on an electrical cable (24') including plural electrical conductors (28'). The female connector includes an insulative housing (34a', 34b') defining a blind cavity (36') therewithin and an axial opening outwardly from the cavity. The housing carries a printed circuit board (166) carrying plural wire-like contacts (40') which individually connect with the conductors of the electrical cable. The wire-like contacts extend into the cavity of the connector for deflecting in spring-like contact with electrical contacts (60) carried by a male connector (20) when the latter is inserted into the cavity of the female connector. A comb feature (50') of the female connector is formed by a strong end wall (138') of the blind cavity and in a respective one of plural slots (48') of the comb feature movably receives a free end portion (46') of each one of the plural wire-like contacts.

Abstract: A combined cardiotomy and venous blood reservoir according to a preferred embodiment of the invention provides a separate in-flow path for both cardiotomy fluid and for venous blood, and includes a cardiotomy fluid filter element also serving as an initial de-foamer. The cardiotomy fluid is de-foamed, filtered, and again de-foamed. The venous blood is de-foamed, and then both fluids are combined for flow from the reservoir. The filter area provided for cardiotomy fluid is advantageously separated from the area of a final de-foamer element. Thus, both the cardiotomy fluid and venous blood may flow through this final de-foamer element simultaneously along separate flow paths. The reservoir design provides greater freedom in selecting adequate filter area for the cardiotomy fluid, while allowing the selection of effective de-foamer element areas in order to achieve acceptable flow rates for both cardiotomy fluid and for venous blood under various conditions of operation for the reservoir.

Abstract: In general, the present invention comprises an holding apparatus for facilitating implantation of a prosthetic heart valve within a mammalian heart. The holding apparatus generally comprises a cage or enclosure having a heart valve prosthesis retention space defined therewith. The proximal end of the holding apparatus is releasably attached to the proximal end of the heart valve prosthesis such that, when the holding apparatus is advanced in a forward direction, a "pulling" force will be exerted upon the proximal end of the prosthesis, rather than a "pushing" force being exerted upon the distal end of the prosthesis.

Abstract: A double lumen tubing which is adapted for use as a catheter. Both lumens of the double lumen tubing have equal cross-sectional areas to provide equivalent flow volumes through each lumen. The lumen wall which divides the outer tubular wall into the two lumens has a central arcuate portion which is shaped to allow insertion of relatively large guidewires through the lumen while at the same time maintaining equivalent cross-sectional areas for each lumen. Resistance to kinking is increased by varying external diameters of each lumen to increase the wall thickness of the tubing in selected areas and by varying the thickness of the wall that divides both lumens at the two joints where the wall meets the tubular wall.

Abstract: Methods for treating glutaraldehyde-fixed collagenous tissues to mitigate their propensity for subsequent calcification and to improve durability. Collagenous tissues which have been harvested and cross-linked by glutaraldehyde are exposed to a carboxyl activating agent to convert the free carboxyl (COOH) groups of the collagen molecules to activated carboxyl moieties (e.g., o-acylisourea). Thereafter, the collagenous tissue is exposed to a compound capable of reacting with the activated carboxyl moieties (e.g., o-acylisourea) to form non-carboxyl side groups. Monofunctional and multi-functional amines are examples of compounds which may be utilized to react with the activated carboxyl moieties to form such non-carboxyl side groups. Thereafter, the collagenous tissue is again exposed to glutaraldehyde. If the non-carboxyl side groups have functional amino groups (NH.sub.