A catheter atherotome and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. An expansible cutter head at the distal end of a catheter includes several elongate flexible members mounted in a parallel array and spaced angularly apart from one another about the associated ends of two concentric members of the catheter in such a way that longitudinal and rotary relative movement of the members of the catheter selectively either bows the flexible members arcuately outwardly into a cutting position or draws them into alignment parallel with the catheter. A sharpened edge of a blade carried on at least one flexible member extends circumferentially and is directed toward the catheter's proximal end when the flexible members are bowed. Partial removal of an atheroma is effected by manually pulling the cutter head past an atheroma with the sharpened edge exposed, with the speed, force, and amount of expansion of the cutter head determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon-tipped catheter or by use of a membrane enshrouding the cutter head to trap the shavings.

Guiding catheter and method of using the same in a cardiovascular procedure such as coronary angioplasty. The catheter has an elongated shaft with a deflectable distal portion. One lumen extends through the elongated shaft to form a passageway through which a dilatation catheter can be introduced. A second smaller lumen extends through the shaft to form a passageway for a control line which passes therethrough and which is connected to the distal tip. Proximal movement of the control line decreases the included angle between the distal portion and the main portion of the shaft. Pull on the control line also exerts a force on the distal portion of the guiding catheter which transmits a resultant axial force to push the catheter disposed within the first lumen. Pull on the control line also allows for catheter tip configuration adjustment thereby enabling the catheter to engage a difficult coronary ostium. In the disclosed embodiments, the distal portion is formed in two sections. Pulling the control line decreases the included angles between the distal sections and the main sections while the distal portion is positioned within a patient. The axial force is particularly advantageous with dilatation catheters to aid in directing the distal end thereof across a lesion.

An improved vascular catheter having a tubular member of composite structure with a tubular substrate and a resin-impregnated fibrous covering extending over a substantial part of the length thereof. The tubular substrate which is longitudinally flexible but relatively inextendible, is preferably polyimide tubing with a lubricious coating on the inner surface thereof defining an inner lumen. The fibrous covering is preferably epoxy-impregnated aramid or polyester (Dacron) multi-filament fibers. The strands are is snugly wrapped around the tubular substrate and then impregnated with a suitable resin. One or more of the strands in the distal portion are at an angle with respect to the longitudinal axis of the tubular substrate between about 20.degree. and about 45.degree. greater than the angle of one or more strands in the proximal portion. Individual strand wraps in the distal portion are at an angle of about 60.degree. to about 85.degree. and strand wraps in such as the proximal portion are at an angle of about 30.degree. to about 60.degree.. The composite tubular member is preferably utilized in balloon dilatation catheters used in angioplasty procedures.

A wire mesh element having soft wire on the outside and precipitation-hardened wire on the inside is used a bushing, seal, seat, or support, and is useful as an end seal for a catalytic converter. The soft wire on the outside can be flat to aid it shielding the internal wire from corrosion due to impingement hot exhaust gasses.

A shaft is shown having inner and outer members in interfering contact along their length, at least one of which comprises a wire, at least a portion of which is superelastic, to achieve substantial mechanical fidelity and resistance to damage. An ultrasound imaging catheter has a hollow catheter shaft, an ultrasound transducer in the shaft, and a drive shaft that rotates the transducer. The shaft comprises at least one metal coil having characteristic elastic deformation under stress in the range of about 3% to 9%, while a restraint means prevents torsional deflection of the coil. A drive shaft having a coil surrounded by a tube, a coil bonded to an inner coaxial cable, and an inner and outer coil that interfere with one another are shown. A superelastic coil is formed by continuously winding a wire about a mandrel, heating a region of the wire to render it superelastic, and after cooling, removing it from the mandrel.