Abstract: A dilatation catheter for delivering a therapeutic agent within a body lumen having a wall with a thickness is provided having a balloon having a flexible wall including a polymer with dispersed nanotubes and pores configured to close below a predefined pressure and to open at or above a predefined pressure. In some embodiments, an actuator is provided to controllably inflate the balloon with a fluid at a pressure sufficient to bring the flexible wall of the balloon into contact with at least a portion of the wall of the body lumen but below the predefined pressure, and to controllably increase the pressure of the fluid within the inflated balloon to at least the predefined pressure at a rate and with a force sufficient to deliver the therapeutic agent from the pores and through at least a portion of the thickness of the wall of the body lumen.

Abstract: Lumen support devices and methods of their use are provided. A lumen support includes one or more plastically deformable cells having two stable configurations with no stable configurations between the two stable configurations. The lumen support device may be plastically deformed to other stable configurations.

Abstract: Methods and apparatus are provided for treating damaged tissue using apparatus that atraumatically delivers a bioactive agent within the tissue, wherein the apparatus provides a column of stem cells may be advanced simultaneously with a needle during needle insertion, and then held stationary or injected at low pressure while retracting the needle. Alternatively, the needle may employ electromotive forces, or to change a dimension of the needle, to expel the bioactive agent into the needle track.

Abstract: A stent is described comprising a unit cell having a negative spring rate and a bistable function. The unit cell comprises first and second segments, the first segment being more rigid than the second segment. The second segment is coupled to the first segment, and the first segment comprises a substantially fixed sinusoidal shape. In the contracted state, the second segment is held stable in a sinusoidal shape, but when a force is applied the second segment bends out to a stable, convex-shaped deployed state. The second segments withstand the application of radial forces in the convex-shaped deployed state, and diametral recoil of the stent is minimized.

Abstract: Interventional catheters are disclosed for use in performing diagnostic and therapeutic procedures in vessels that are accessed retrograde to blood flow. The catheters include an elongated shaft slidably disposed within a sheath, a distal region having an end effector and a filter disposed proximal to the end effector to capture emboli liberated during the diagnostic or therapeutic procedure. The filter includes a plurality of struts that cooperate with an exterior surface of the catheter to define a reservoir to retain captured emboli, the reservoir configured so that advancement of the sheath contracts the filter without squeezing or dislodging captured emboli beyond a distal end of the filter.

Abstract: Microcatheters catheters are provided having balloons incorporating radiopaque nanoparticles. Optionally, carbon nanotubes dispersed within the shaft may be configured to react to electrical stimulation, thereby providing a steerable distal end region on the microcatheter. Methods of making the foregoing microcatheters also are provided.

Abstract: The present invention provides and apparatus and methods for emboli removal and stenting within the renal arteries having a catheter system having a distal occlusion element, a stent deployment section, and an emboli removal lumen. The occlusion element is disposed at a predetermined distance from the stent deployment section specific for use in the renal artery, and is constructed to reduce the potential for perforation or jailing during stent deployment. The apparatus further includes an array of radio-opaque markers disposed on the stent delivery catheter to facilitate accurate stent deployment within a renal artery.

Abstract: Expandable biodegradable devices formed of bistable and multistable unit cells for use in devices, such as stents and graft systems, are provided, in which the device has two or more stable configurations, including a contracted configuration and an expanded configuration, the contracted stable configuration having a smaller diameter than the expanded configuration.

Abstract: Vascular prostheses and methods of use are provided, wherein the vascular prosthesis includes a plurality of bistable unit cells configured to form a helical structure. A visualization catheter also is provided for use ensuring accurate measurement of a lesion and ensuring delivery and placement of the vascular prosthesis.