Catheter with controllable stiffness and method for operating a selective stiffening catheter

A controllable stiffness catheter, comprising:

• a shaft having a stiffness sheath and an access lumen;
• a stiffness device having a heater and a melting binder in thermal contact with said heater, said stiffness device being disposed in said stiffness sheath, said binder having a transition temperature and being substantially solid at body temperature and softening as said heater warms said binder above said transition temperature;
• and
• a power controller electrically connected to said heater and selectively supplying power to said heater to change a stiffness of said stiffness sheath between a relatively stiff state when said heater is not powered by said power controller and a relatively soft state when said heater is powered by said power controller.

A controllable stiffness catheter, comprising:

• a shaft having a stiffness sheath and an access lumen;
• means for controlling stiffness disposed in said stiffness sheath, said stiffness controlling means being substantially solid at body temperature and softening above body temperature;
• and
• means for supplying heat to said stiffness controlling means to change a stiffness of said stiffness sheath between a relatively stiff state and a relatively soft state.

A controllable stiffness catheter, comprising:

• a shaft having a stiffness sheath and an access lumen;
• a stiffness device disposed at said stiffness sheath and being in a relatively stiff state at or below a first temperature and being in a relatively soft state at or above a second temperature;
• a temperature-changing device in thermal contact with said stiffness device, said temperature-changing device changing a temperature of said stiffness device at least below said first temperature and above said second temperature;
• and
• a power controller electrically connected to said stiffness device and selectively supplying power to said temperature-changing device to change a stiffness of said stiffness device between said stiff state and said soft state.

A method for manufacturing a controllable stiffness catheter, which comprises:

• providing a shaft with a stiffness sheath and an access lumen;
• disposing a heater inside the stiffness sheath;
• filling the stiffness sheath containing the heater with a binder to at least partially surround and thermally contact the heater, the binder being substantially solid at body temperature and softening above body temperature;
• and
• selectively supplying power to the heater to change a stiffness of the stiffness sheath between a relatively stiff state when the heater is not powered and a relatively flexible state when the heater is powered.

A method for operating a selective stiffening catheter, which comprises:

• placing a selective stiffening catheter in a relatively flexible state;
• traversing a natural passage of the body with the catheter in the flexible state;
• and
• changing the catheter to a relatively stiffer state to substantially maintain a current shape of the catheter in the body.

A method for treating a Chronic Total Occlusion, which comprises:

• extending a guidewire to a CTO treatment site in a body;
• providing a controllable stiffness catheter with:
• a shaft having a stiffness sheath and an access lumen;
• a stiffness device disposed at the stiffness sheath and being in a relatively stiff state at or below a first temperature and being in a relatively soft state at or above a second temperature;
• a temperature-changing device in thermal contact with the stiffness device, the temperature-changing device changing a temperature of the stiffness device at least below the first temperature and above the second temperature;
• and
• a power controller electrically connected to the stiffness device and selectively supplying power to the temperature-changing device to change a stiffness of the stiffness device between the stiff state and the soft state.
• threading the catheter along the guidewire up to the CTO in the soft state;
• changing a stiffness of the stiffness sheath to the stiff state without straightening the catheter;
• and
• projecting the guidewire through the CTO.