Abstract: A cannula for insertion into a body cavity, duct, or vessel of a patient includes a parent cannula member and an integral radiopaque tip. The tip is configured so as to be distinguishable from internal body parts in an X ray or flouroscopic image, thus serving to precisely locate the position of the cannula within the patient without substantially obstructing the physician's view of such body parts. The cannula tip and parent member are separately pre-formed from a non-toxic polymeric material and can be constructed so as to have different hardnesses. In one embodiment the tip is softer than the parent member in order to prevent internal injury to the patient, while in a second embodiment the tip is harder than the parent member for facilitating certain catheterization applications. The pre-formed tip and parent member are then dielectrically heated and welded securely together to form a unitary, integral cannula.

Abstract: The oxygenater heat exchanger disclosed utilizes a heat transfer tube having several tube legs arranged in closely spaced, parallel relation. A resilient central core fits resiliently within the tube legs and cooperates with spiral ribs on the tube and with the housing to form blood flow spiral passages down around the exterior of each of the tube legs. The blood inlet is positioned to enhance efficient heat exchange.

Abstract: An improved stent for prosthetic tissue heart valves having upright legs which have radiused upper tips which are approximately one-half the width of prior art stent legs is disclosed. These narrow tipped stent legs reduce stress induced in the leaflets by curvature of the leaflets around the tips of the stent legs in the closed position, extending the service life of the valve. Tabs are added to the tips of the stent legs to add structural strength. These tabs can be tapered or straight but their bottom portions must be narrower than the stent leg. The tabs have a plurality of holes in them through which coaptation stitches are passed. The coaptation stitch can be two separate stitches, one in a first plane and one in a second plane at 90.degree. to the first plane, or, in the preferred embodiment, a single figure eight stitch passing through the holes in the tab in a plane coincident with the long axis of the stent leg.

Abstract: A cannula for insertion into a body cavity, duct, or vessel of a patient includes a parent cannula member and an integral radiopaque tip. The tip is configured so as to be distinguishable from internal body parts in an X ray or flouroscopic image, thus serving to precisely locate the position of the cannula within the patient without substantially obstructing the physician's view of such body parts. The cannula tip and parent member are separately pre-formed from a non-toxic polymeric material and can be constructed so as to have different hardnesses. In one embodiment, the tip is softer than the parent member in order to prevent internal injury to the patient, while in a second embodiment the tip is harder than the parent member for facilitating certain catheterization applications. The pre-formed tip and parent member are then dielectrically heated and welded securely together to form a unitary, integral cannula.

Abstract: Prosthetic heart valves comprising an annular, right cylindrical, metal stent covered with fabric to which a glutaraldehyde-stabilized pericardial valving element formed of three leaflets, each having a plateau on a truncated triangle extending higher at the center than at the edges, and formed as a cylinder having a diameter substantially equal to the diameter of the stent, and having a low profile is disclosed.

Abstract: This invention relates to the electrochemical machining of integrally formed prosthetic heart valve structures in which both the structural integrity of the valve and the blood flow through the valve is improved as a result of the integral formation of the valve structure. In particular, such heart valves comprise a ring and a pendant structure, such as a strut, for supporting the opening and closing of a discoid valve occluder. Integral formation of the strut with the ring permits the cross-sectional shape of the strut to be machined without overheating and distortion to conform to a teardrop shape having favorable fluid-dynamic characteristics thereby improving the flow of blood through the valve across the strut. The integral formation of the strut with the ring further results in the elimination of the weld fillet between the strut and the ring, thereby permitting the height of the ring to be reduced, which further improves the fluid dynamic characteristics of the valve.

Abstract: Apparatus for the distention and irrigation of a saphenous vein which is being tested prior to use as a coronary or peripheral bypass graft includes a specially-configured cannula for insertion into the vein, and a pressure-limiting device having a resilient membrane reservoir which limits the hydrostatic pressure delivered to the vein to a predetermined level. The device is connected between the cannula inserted into the vein and a syringe filled with irrigation fluid. As fluid is delivered under pressure from the syringe, the membrane reservoir fills with fluid and inflates within a specified range of pressures so that if excessive force is applied to the syringe, the membrane inflates, and the pressure transmitted to the vein cannot exceed a predetermined maximum pressure. A stopcock connected between the syringe and the membrane allows the membrane to be pressurized with the contents of the syringe.

Abstract: A tracheostomy tube includes an outer cannula and a removable, disposable inner cannula. The inner cannula is provided with a tapered portion located just behind its distal tip which forms simultaneously an air tight seal with the outer cannula and a stop device for preventing the protrusion of the tip substantially beyond the end of the outer cannula. The stop device furthermore compensates for variations in the length of the inner cannula by controlling the position of the tip between a location flush with the end of the outer cannula and one just slightly beyond. A coupling connector is mounted on the proximal end of the inner cannula to provide easy, releasable attachment of the inner cannula to the outer cannula. The inner cannulae are inexpensively constructed from a soft, flexible polyvinyl chloride material and are dimensionally compatible with any particular outer cannula.