Thrombus removal system and process

• US 7,955,345 B2
• Filed: 02/16/2006
• Issued: 06/07/2011
• Est. Priority Date: 04/01/2005
• Status: Active Grant

• Current Assignee: Nexgen Medical Systems, Inc.
• Original Assignee: Nexgen Medical Systems, Inc.
• Inventors: Kucharczyk, John, Finitsis, Stephanos
• Primary Examiner(s): Ho; (Jackie) Tan-Uyen T
• Assistant Examiner(s): EASTWOOD, DAVID C
• Application Number:
  US11/356,321
• Publication Number:
  US 20060224179A1
• Time in Patent Office: 1,937 Days
• Field of Search: 606/110, 606/113, 606/127, 606/159, 606/192, 606/200
• US Class Current: 606/159
• CPC Class Codes: A61B 17/12022 Occluding by internal devices, e.g. balloons or releasable wires plugging an opening in the wall of an organ A61B17/0057; occluders for the cervical canal A61F6/146; vas deferens occluders A61F6/20
• CPC Class Codes: A61B 17/1214 Coils or wires
• CPC Class Codes: A61B 17/12145 having a pre-set deployed three-dimensional shape methods of manufacturing A61B2017/00526
• CPC Class Codes: A61B 17/1215 comprising additional materials, e.g. thrombogenic, having filaments, having fibers, being coated
• CPC Class Codes: A61B 17/1219 expandable in contact with liquids
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/32056 Surgical snare instruments for removing or smashing calculi A61B2017/2212; tonsillotomes A61B17/26
• CPC Class Codes: A61B 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/2212 having a closed distal end, e.g. a loop
• CPC Class Codes: A61F 2002/016 made from wire-like elements
• CPC Class Codes: A61F 2230/0078 hyperboloidal
• CPC Class Codes: A61F 2230/0091 helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section

Abstract

A device capable of capturing and facilitating the removal of a thrombus in blood vessels (or stones in biliary or urinary ducts, or foreign bodies) uses a soft coil mesh with the aid of a pull wire or string to engage the surface of a thrombus, and remove the captured thrombus. The soft coil mesh is formed by an elongated microcoil element that forms the helical elements of a macrocoil element. The microcoil element provides a relatively elastic effect to the helical elements forming the macrocoil and allows for control of gripping forces on the thrombus while reducing non-rigid contact of the device with arterial walls. The use of multiple coil mesh elements, delivered through a single lumen or multiple lumens, preferably with separate control of at least one end of each coil, provides a firm grasp on a distal side of a thrombus, assisting in non-disruptive or minimally disrupted removal of the thrombus upon withdrawal of the device.

Claims

1. A method of using a medical device comprising:

two microcatheter lumens, each lumen containing;

a macrocoil thrombus engaging component having a length with a proximal end and a distal end, the length of the macrocoil comprised of microcoils that allow the length of the macrocoil to be extendable and flexible and which microcoils increase the flexibility and conformability of the macrocoil;

a first wire capable of providing force on the distal end of the macrocoil;

a second wire capable of providing force on the proximal end of the macrocoil;

wherein for at least one macrocoil thrombus engaging coil;

a microguidewire is passed through at least one of the lumens to help pass a microcatheter through a larger guiding catheter and to place the microcatheter distal to the thrombus, particularly passing between the clot and the vessel wall;

removing the microguidewire;

a macrocoil pull-string system comprising push-pull capability is passed through the at least one of the lumens of the microcatheter(s);

the macrocoil pull-string system is passed distal to the clot;

the macrocoil pull-string system is used to form an at least partially enclosing distal meshwork on the distal surface of the thrombus;

macrocoils are extended from the microcatheter as it is partially withdrawn, passively encircling around the clot as a meshwork with exterior surfaces of the macrocoils contacting the clot;

progressively pulling on the pull string so that the meshwork becomes more tightly engaged with the clot and conforms more to a shape of the clot.

3. A method of claim 1 wherein two lumens are present within at least one microcatheter, each of the two lumens transporting a macrocoil pull string system.

4. A method of claim 1 wherein the at least one set of microcoils of at least one macrocoil exhibits a conformation memory of an amorphous shape with overlapping structure resisting complete elongation when ends of the at least one macrocoil are stressed.

5. The method of claim 4 wherein the conformation memory forms at least one structure selected from the group consisting of knots, loops, multiple crossovers, kinks and snags to reduce excessive slipping of macrocoils, which slipping would allow linear extension of macrocoil material.

6. The method of claim 5 wherein the at least one structure assists in forming a network comprising the at least one macrocoil engaging a distal surface of the thrombus.

7. The method of claim 6 wherein the at least one macrocoil encircles the distal side of the thrombus as the at least one macrocoil is extended from the microcatheter.

8. The method of claim 1 wherein a pull-string is used to tighten the at least one macrocoil against the distal side of the thrombus.

10. The method of claim 3 wherein a pull string is attached to a macrocoil within each lumen of a two-lumen microcatheter and each pull string is used to tighten a meshwork of macrocoils around the thrombus prior to removal of the thrombus.

13. The method of claim 1 wherein passively encircling the clot as a meshwork places essentially only external surfaces of the microcoil against external surfaces of the clot.

2. A method of using a medical device comprising:

two microcatheter lumens, each lumen containing;

a macrocoil thrombus engaging component having a length with a proximal end and a distal end, the length of the macrocoil comprised of microcoils that allow the length of the macrocoil to be extendable and flexible and which microcoils increase the flexibility and conformability of the macrocoil;

a first wire capable of providing force on the distal end of the macrocoil;

a second wire capable of providing force on the proximal end of the macrocoil;

wherein there are at least two macrocoil thrombus engaging coils within two separate microcatheters or adjacent lumens of a single microcatheter, the method comprising;

a microguidewire positions a first microcatheter of the at least two microcatheters distal to the thrombus;

a second microcatheter of the at least two microcatheters is positioned distal to the thrombus;

a macrocoil pull string system is passed through the lumen of the first microcatheter with the distal tip of the first microcatheter extending beyond the thrombus;

a second macrocoil pull string system is passed through the lumen of the second microcatheter and the second macrocoil pull string system is extended distal to the thrombus;

portions of the macrocoils are interlaced into a meshwork over the thrombus by use of the pull strings to place external surfaces of macrocoil loops into contact with the thrombus;

macrocoils from each of the at least two macrocoil pull strings systems are passively wound around at least the mid and distal portions of the thrombus;

the pull strings are used to tighten the meshwork around the thrombus;

the at least two macrocoil pull strings and mesh work pull the thrombus out of the artery .

9. The method of claim 2 wherein two separate pull strings are used to aid in interlacing the macrocoils and/or tighten the at least two macrocoils against the distal side of the thrombus.

14. The method of claim 2 wherein passive winding of the macrocoil around at least the mid and distal portions of the thrombus places essentially only external surfaces of the microcoil against the thrombus.

11. A method of using a medical device for removing a thrombus from a blood vessel, the medical device comprising at least two microcatheter lumens, each lumen containing:

a macrocoil thrombus engaging component having a length with a proximal end and a distal end, the length of the macrocoil comprised of microcoils that allow the length of the macrocoil to be extendable and flexible and which microcoils increase the flexibility and conformability of the macrocoil;

a first wire capable of providing force on the distal end of the macrocoil;

a second wire capable of providing force on the proximal end of the macrocoil at least one macrocoil thrombus engaging coil;

the method comprising steps of passing a microguidewire through at least one of the lumens to help pass a microcatheter through a guiding catheter larger than the lumens and placing the microcatheter distal to the thrombus, including passing between the clot and the vessel wall;

the medical device further comprising a macrocoil pull-string system comprising a push-pull capability that is passed through the at least one of the lumens of the microcatheter(s);

passing the macrocoil pull-string system distal to the clot;

the macrocoil pull-string system is used to form an at least partially enclosing distal meshwork on the distal surface of the thrombus;

macrocoils are extended distally from the microcatheter as it is partially withdrawn, passively encircling meshwork around the clot to place external surfaces of macrocoil loops into contact with the clot; and

the pull string is progressively pulled so that the meshwork becomes more tightly engaged with to the clot.

12. The method of claim 11 wherein the microguidewire is withdrawn at least partly into the at least one lumen before the macrocoil pull-string system is progressively pulled.