Vascular filter with improved strength and flexibility

A method for preventing embolism and microembolism in a blood flow circuit incident to performance of a treatment at a location in a blood vessel, said method comprising:

• introducing a first filter element into the blood vessel downstream of the location so that the first filter element obturates the blood vessel;
• performing the treatment;
• introducing a second filter element into the blood vessel upstream of the location so that the second filter element obturates the blood vessel;
• and
• after the step of performing a treatment, bringing the first and second filter elements close to one another, radially collapsing the first and second filter elements and withdrawing the first and second filter elements from the blood vessel,
• wherein said treatment is one of:
• disintegrating an obstruction in the blood vessel with laser radiation;
• disintegrating an obstruction in the blood vessel with ultrasound energy;
• disintegrating an obstruction in the blood vessel by mechanical cutting;
• angioplasty;
• and stenting.

A system for preventing embolism and microembolism in a vascular system, said system comprising:

• a guiding catheter having an outer surface;
• a blocking balloon carried by said guiding catheter on said outer surface
• an elongated support element arranged to extend through, and beyond, said guiding catheter;
• a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;
• a second filter element surrounding said support element and radially expandable from a closed condition to an open condition;
• and
• means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions,
• wherein each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood.

A system for preventing embolism and microembolism in a vascular system, said system comprising:

• an elongated support element;
• a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;
• a second filter element surrounding said support element and radially expandable from a closed condition to an open condition;
• and
• means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, wherein
• each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood;
• and
• at least one of said filter elements comprises:
• an armature constituted by a mesh or screen made of a resiliently deformable material;
• and a, sheet of polymer filter material secured to said armature and providing said filter surface.

A system for preventing embolism and microembolism in a vascular system, said system comprising:

• an elongated support element;
• a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition;
• a second filter element surrounding said support element and radially expandable from a closed condition to an open condition;
• and
• means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, wherein:
• each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood;
• and
• one of said filter elements comprises:
• an armature made of a resiliently deformable material and having an open end;
• a sheet of polymer filter material secured to said armature and providing said filter surface;
• a flexible additional filter sheet secured to the open end of said armature;
• and
• a wire attached to said flexible additional filter sheet and extending to a point outside of the vascular system, said wire being movable at the point outside of the vascular system to alter the shape of said flexible additional filter sheet.

A method for performing angioplasty comprising:

• aligning a first balloon with an obstruction in a blood vessel, the first balloon being radially outwardly expandable;
• interposing a second balloon between the first balloon and the obstruction, the second balloon being annular so as to enclose a space, and being radially outwardly expandable;
• expanding the first balloon to support the second balloon;
• expanding the second balloon to dilate the obstruction;
• blocking blood flow in the vessel at a location downstream of the obstruction;
• deflating and withdrawing the first balloon;
• performing a procedure on the blood vessel between the location where the blood vessel is blocked and the second balloon by introducing a treatment device or substance through the space enclosed by the second balloon.