Abstract: A gas turbine engine with a closed loop working fluid cycle.

Abstract: An improved arterial catheter device for capturing emboli within the aorta and other arteries is described. The system typically includes an elongated catheter member bearing a filtration apparatus disposed at its the distal region, comprising a filter membrane and a mechanism for deploying and collapsing the filter. For reliable deployment, the deployment mechanism comprises at least one pair of struts, one being a compression strut and the other a tension strut. In use, the catheter is positioned so that the filter membrane is down stream from the possible embolic source and upstream from any vital organs of concern. When deployed the filter membrane will capture emboli from the blood stream, and upon filter removal will extract the emboli from the patient.

Abstract: An improved arterial catheter device for capturing emboli within the aorta and other arteries is described. The system typically includes an elongated catheter member bearing a filtration apparatus disposed at its the distal region, comprising a filter membrane and a mechanism for deploying and collapsing the filter. For reliable deployment, the deployment mechanism comprises at least one pair of struts, one being a compression strut and the other a tension strut. In use, the catheter is positioned so that the filter membrane is down stream from the possible embolic source and upstream from any vital organs of concern. When deployed the filter membrane will capture emboli from the blood stream, and upon filter removal will extract the emboli from the patient.

Abstract: A drug storing and metering stent for placement within a vessel comprising an outer member having a lumen, an inner member positioned within the lumen of the outer member. A space separates the inner member from the outer member and within which space a therapeutic drug is disposed. The stent includes at least one protrusion provided on at least one of the inner and outer members and extending across the space so as to cause a friction fit between the inner and outer members. The stent also includes a pattern of perforation across both the inner and outer members to permit the stent to expand radially. The invention also relates to a method of making such a stent, and a method of releasing a therapeutic drug within a vessel.

Abstract: The invention relates to a catheter and guidewire exchange system in which the guidewire is contained within an indwelling portion of the catheter and with the guidewire and the catheter being separated externally of the patient. The catheter includes a guidewire lumen and a longitudinal slit which penetrates through the catheter wall and into the guidewire lumen. The catheter walls adjacent the slit are provided with reinforced edges which function to maintain the slit in a normally closed position during the catheterization procedure, when desired.

Abstract: An angioplasty guidewire includes a proximal shaft and an intermediate section extending from the shaft to a distal joint and having a stiffener and a flexible member. The stiffener and the flexible member are disposed in coaxial slidable relationship and operable, as the stiffener and flexible member undergo relative axial shifting, to cooperatively impart a variable stiffening force on the intermediate section. A flexible distal tip mounts to the end of the intermediate section and projects axially therefrom.

Abstract: The invention relates to an apparatus and method for limiting the pressure of inflation fluid injected into a drug delivery catheter balloon, while permitting continuous and uninterrupted flow of such fluid to the balloon. The apparatus includes an elongated hollow housing having a fluid entrance, a fluid exit and a bore extending therebetween which forms an interconnecting chamber and passageway. A piston and piston shaft assembly is disposed inside the housing and is longitudinally movable within the chamber. The piston and piston shaft assembly is biased against the fluid pressure of the fluid entering the housing by a spring. The piston shaft has a distal end which extends toward the passageway inlet. As the incoming fluid pressure increases and approaches the predetermined maximum pressure level of the apparatus, the piston shaft distal end moves within the chamber against the biasing force of the spring toward a position adjacent the passageway inlet.

Abstract: The invention relates to an apparatus and method for limiting the pressure of inflation fluid injected into a drug delivery catheter balloon, while permitting continuous and uninterrupted flow of such fluid to the balloon. The apparatus includes an elongated hollow housing having a fluid entrance, a fluid exit and a bore extending therebetween which forms an interconnecting chamber and passageway. A piston and piston shaft assembly is disposed inside the housing and is longitudinally movable within the chamber. The piston and piston shaft assembly is biased against the fluid pressure of the fluid entering the housing by a spring. The piston shaft has a distal end which extends toward the passageway inlet. As the incoming fluid pressure increases and approaches the predetermined maximum pressure level of the apparatus, the piston shaft distal end moves within the chamber against the biasing force of the spring toward a position adjacent the passageway inlet.

Abstract: A self-sealing hemostatic valve for use in a catheter apparatus is disclosed, comprising a proximal valve element having a sealing hole, a distal valve element having a flap and biasing means to enhance the force with which the flap bears against the distal side of the proximal valve element to normally seal the hole. The sealing hole seals about an instrument passed through the valve and the flap seals the valve when no instrument is present. The proximal face of the proximal valve element is provided with discontinuities that increase the flexibility of the proximal valve element in a distal direction.

Abstract: An elongate flexible wire-like medical device, such as a guidewire for use with a catheter, is formed with a shaft in which the difference between the magnitude of the tensile yield stress and compressive yield stress of the shaft is substantially reduced. The guidewire exhibits superior kink resistance without compromising other desirable characteristics and enables a guidewire to be made in a smaller diameter without loss of performance. The guidewire shaft may be formed from a precipitation hardenable alloy such as an alloy of nickel, cobalt, molybdenum and chromium (MP35N and Elgiloy), 455PH stainless steel or stainless steel alloy 1RK91. Also disclosed is a process for increasing the modulus of elasticity of an alloy of nickel, cobalt molybdenum and chromium. Further, the disclosure relates to an improved management and manufacturing process for constructing the tip of a medical guidewire.

Abstract: A bidirectional steering catheter comprising a distal electrode assembly, a flexible tip assembly, an elongated shaft having a central lumen running the length of the shaft, and a handle/actuator. A plurality of ring electrodes are attached to the surface of the flexible tip assembly. Signal wires running the length of the catheter are electrically connected to each ring electrode. At least two pull cables having first and second ends extend distally through the central lumen. The first end of each pull cable is attached to the handle/actuator. The second end of each pull cable is attached to the distal electrode assembly, such that the distal electrode assembly may be moved between a first and a second position within a single plane by manipulating the handle/actuator. At least two reinforcement members are located inside the flexible tip assembly. Each reinforcement member has a proximal section, a middle section and a distal section.

Abstract: Devices have been made which are balloon catheters, preferably PTCA devices, and which are capable of selectively directing inflation forces against the thicker part of an eccentric arterial obstruction or an off-center plaque deposit. In a first embodiment, a balloon catheter is formed from at least two balloons positioned side-by-side to each other. One balloon is larger in diameter than the other balloon(s). The larger diameter balloon acts as a cushion to the thinner part of a lesion. The small balloon(s) focuses greater inflation force against the thicker part of the lesion. In a second embodiment, a unitary balloon catheter has a plurality of independently inflatable lobes. Inflation forces may be selectively directed depending on which lumen of the balloon catheter is pressurized. Additionally, different lumens can be used for other purposes including an auto-perfusion catheter and monorail applications.

Abstract: A dilatation balloon having at least one helical groove disposed in at least a portion of the dilating surface of the dilatation balloon is mounted on the distal end of a catheter shaft. Multiple helical grooves may be provided in the dilatation balloon extending parallel to each other or opposite to each other in the dilating surface. Each helical groove has a pitch, width and depth. According to one aspect of the invention, the pitch, width and depth of the helical groove, as well as the number of grooves, are selected to allow perfusion of blood past the dilatation catheter when the dilatation balloon is inflated in a blood vessel. According to another aspect of the invention, the pitch, width, and depth of the helical groove, as well as the number of grooves, are selected so that the dilatation balloon conforms to a tortuous blood vessel and does not straighten the blood vessel during dilation.

Abstract: A catheter with an integral steerable guidewire converts linear movement of the guidewire to rotational movement at the distal end of the guidewire. The catheter has a guidewire lumen to receive the guidewire. The catheter and guidewire are constructed so that the guidewire can be reciprocated and rotated with respect to the catheter. The guidewire and catheter cooperate in a manner so that when the guidewire is reciprocated axially with respect to the catheter, that axial movement of the guidewire is converted into rotational movement.