Endovascular sheath with gradable stiffness device and method

An endovascular sheath apparatus comprising:

• an inner tube that includes a lumen for introducing medical fluids or devices and an outer surface;
• an outer tube with an interior surface, the outer and inner surfaces defining a cavity therebetween;
• a stiffening component that is at least partially received in and may move within at least part of the cavity, the stiffening component having one or more helical members and a distal end that is bonded to a distal end of the inner tube;
• an actuating mechanism that cooperates with a proximal end of the stiffening component, the stiffening component having a cross section with an adjustable pitch between adjacent turns of the one or more helical members and thus imparting to the inner tube a stiffness characteristic that is influenced by the actuating mechanism, the actuating mechanism moving axially, rotationally or helically, the stiffness component thereby moving within the cavity without incursion into the lumen of the inner tube in response to axial, rotational, or helical displacement of the actuating mechanism, the actuating mechanism thereby adjusting the stiffness of the endovascular sheath.