Medical devices which are currently proposed to use elements made from shape memory alloys may be improved by the use of stress-induced martensite alloy elements instead. The use of stress-induced martensite decreases the temperature sensitivity of the devices, thereby making them easier to install and/or remove.

Medical devices incorporating SIM alloy elements

An improved guiding member for use within a body lumen having a unique combination of superelastic characteristics. The superelastic alloy material has a composition consisting of about 30% to about 52% (atomic) titanium, and about 38% to 52% nickel and may have one or more elements selected from the group consisting of iron, cobalt, platinum, palladium, vanadium, copper, zirconium, hafnium and niobium. The alloy material is subjected to thermomechanical processing which includes a final cold working of about 10 to about 75% and then a heat treatment at a temperature between about 450° and about 600° C. and preferably about 475° to about 550° C. Before the heat treatment the cold worked alloy material is preferably subjected to mechanical straightening. The alloy material is preferably subjected to stresses equal to about 5 to about 50% of the room temperature ultimate yield stress of the material during the thermal treatment. The guiding member using such improved material exhibits a stress-induced austenite-to-martensite phase transformation at an exceptionally high constant yield strength of over 90 ksi for solid members and over 70 ksi for tubular members with a broad recoverable strain of at least about 4% during the phase transformation. An essentially whip free product is obtained.

Superelastic guiding member

A catheter device incorporating combined ultrasound ablation and balloon dilation components. The catheter device generally comprises an elongate catheter body having proximal and distal ends and an outer surface. Disposed on the outer surface of the catheter body is a dilation balloon. At least one balloon inflation lumen fluidly connects the proximal end of the catheter body to the dilation balloon to permit injection of inflation fluid into the dilation balloon. Extending longitudinally through the catheter body is an ultrasound transmission member having a proximal end and a distal end, with the proximal end being connectable to an ultrasound transducer such that ultrasonic energy will pass through the ultrasound transmission member to the distal end thereof. In alternative embodiments of the present invention, there are provided catheter devices incorporating combined ultrasound ablation and laser ablation components as well as combined ultrasound ablation and atherectomy ablation components.

Angioplasty and ablative devices having onboard ultrasound components and devices and methods for utilizing ultrasound to treat or prevent vasospasm

Method of inserting medical devices incorporating SIM alloy elements

A guidewire (10) and a method for its manufacture, wherein at least the distal portion (18) of the guidewire (10) comprises an element made of a precursor of a superelastic alloy such as a Ni-Ti linear elastic alloy. The element exhibits a stress-strain curve with a linear stress-strain relationship and a yield point. At room temperature to body temperature the precursor is in the martensitic phase. The distal portion (18) of the guidewire (10) is deformable beyond the yield point by the physician in the field to a desired set shape and exhibits resistance to kinking during insertion into the body as a result of its elasticity.

High elongation linear elastic guidewire

A coupling for tubes, pipes or the like, fabricated of heat recoverable metal that is treated so that it will contract when heated above its transition temperature spontaneously expand when cooled to its transition temperature to permit it to be installed or removed from the pipes.

Heat recoverable metallic coupling

Nickel/titanium alloys containing less than a stoichiometric quantity of titanium, which have a high austenitic yield strength and are capable of developing the property of shape memory at a temperature above 0° C., may be stabilized by the addition of from 7.5 to 14 atomic percent copper. These stabilized alloys also possess improved workability and machinability.

Nickel/titanium/copper shape memory alloy

Nickel/titanium alloys containing less than a stoichiometric quantity of titanium, which are capable of having the property of heat recoverability imparted thereto at a temperature above the boiling point of liquid nitrogen, may be stabilized by the addition of from 1.5 to 9 atomic percent copper. These stabilized alloys also possess improved workability and machinability.

John D. Harrison

Papers

Heat recoverable metallic coupling

Nickel/titanium/copper shape memory alloy

Heat recoverable nickel/titanium alloy with improved stability and machinability

The origins of the shape memory effect