The present invention relates to a hollow tube or cannula carrying a core wire having different or variable diameter core spacing (the space between the tube and the core wire) wherein the core wire is movably disposed within the elongated hollow tube or cannula and is adopted for use with a coaxially actuated medical device, and relates to a medical device system. As one example, the hypotube or cannula based medical device with an internal core wire and variable core spacing may be used to activate a distal device during a vascular procedure or a procedure on a carotid artery.
Hypotubes or cannula-based medical devices with internal core wires are used to activate many different, distally located medical devices, herein generally identified as “medical device systems.” The present invention can be adapted for use in a relatively wide variety of “wire in a hollow tube” medical device systems. An exemplary list of medical device systems include: (1) Debris/Foreign Body Retrieval devices—similar to a gooseneck snare and the radially actuated basket (proximally located at or near the end of the medical device system) used to retrieve loose stents, ruptured catheters & angioplasty balloons, etc.; (2) Stone Retrieval devices—similar to stone retrieval baskets used to retrieve gall stones, kidney stones, etc.; (3) Distal (or Embolic) Protection devices—such as SCI-PRO, ANGIOGUARD, GUARDWIRE products which provide protection from debris embolizing during intravascular interventional procedures such as PTCA (Percutaneous Transluminal Coronary Angioplasty) and coronary stenting, carotid stenting, peripheral PTA (Percutaneous Transluminal Angioplasty) and stenting, mechanical thrombectomy, etc.; (4) Biopsy retrieval devices that are manipulated proximally to operate a distal component to retrieve tissue samples; (5) Guidewires used to track & guide devices to percutaneous treatment sites and guidewires with a straightenable J-Tip; (6) Interventional Catheters—such as PTCA, PTA, etc balloon catheters, angiogenisis; (7) Delivery Sheaths—such as those used to deliver Nitinol (self-expanding) stents; (8) Laparoscopic instruments—such as those currently used to remove the gall bladder, appendix, etc.; (9) Temporary IVC Filter catheters such as catheter with a basket at the tip that is temporarily deployed to prevent clots from traveling to the lungs resulting in pulmonary embolisms; and (10) Electrophysiology (EP) devices such as mapping catheters and tip ablation. One example of a coaxially actuated medical device deployed at the distal end of a medical device system is disclosed in U.S. Pat. No. 6,537,296 to Levinson. Other coaxially activated medical devices may be utilized.
As a more specific example, a health professional first introduces a guide wire or catheter (a hollow tube with a movably disposed central core wire) into a vein, artery, or other body cavity of a patient. During catherization of the heart, the guide or catheter is inserted often times into the femoral artery. The hypotube cannula is disposed and moves over the central core wire. The health professional, typically with assistance of various imaging systems, guides the guide wire or catheter through the vascular system of the patient. Occasionally, the guide wire or catheter encounters extremely tortuous pathways in the patient's system.
Sometimes medical devices, mounted on a distal end portion of the medical device system, are coaxially actuated based upon longitudinal movement of the core wire with respect to the cannula. These medical device systems are sometimes difficult to deploy and the health professional may encounter resistance in the longitudinal movement of the core wire with respect to the hollow tube (cannula). This resistance adversely effects the coaxially deployment or retraction of the medical instrument at the distal end of the catheter system. The problem is due to the number of twists and turns of the medical device system (the elongated hollow tube and the core wire) deployed in a tortuous body system, such as the vascular system. The sum of the friction, caused by the core wire contacting the inside surface of the elongated cannula, adversely effects the deployment and retraction of coaxially actuated medical device at the distal end of the system. These coaxially actuated medical devices, such as a basket, filter, balloon, stent or other coaxial medical elements, are opened and closed based upon relatively small axial movement of the tube with respect to the central core wire. Since the medical device system twists and turns in the patient and since the total frictional force is the sum of all areas of contact between the hollow tube and the central core wire, which contact areas increase dependent upon the degree of curvature of each twist or turn and number of tortuous incidents along the length of the system, this increase in the total friction of the system adversely effects the deployment and retraction of the basket or other medical devices at the distal end of the system. Essentially, the total friction is the sum of all areas of contact between the outer diameter of the core wire and the inner diameter of the cannula or hollow tube. This is the interior core space. The greater the length of the tortuous pathway and/or the greater the number of contact points, the greater the sum of friction along the length of the system and the greater amount of force required to overcome that friction in order to deploy or retract axially actuated medical devices at the distal end of the system (to move one wire relative to the other).
A a lubricious coating such as Teflon or PTFE or silicon, on the central core wire may reduce this friction.
It is an object of the present invention to provide a core wire in a hollow tube with variable core space dimensions (the space between the central wire and the tube) thereby reducing the friction points between the outer dimension of the core wire and the inner dimension of the elongated hollow tube (hypo-tube).
It is a further object of the present invention to provide a plunge ground core wire.
It is an additional object of the present invention to provide a core wire which is plunged ground at periodic intervals.
It is a further object of the present invention to provide a core wire that is braided thereby providing a multiplicity of core wire outer diameters.
It is a further object of the present invention to provide an elongated tube or cannula formed of a plurality of braided wires.
It is an additional object of the present invention to provide a medical device system with a hollow tube formed with a plurality of braided wires and/or a core wire formed of a different plurality of braided wires.
It is a further object of the present invention to provide an elongated core wire having various outer diameters over its length, none larger than the inside diameter of the hollow tube.
It is another object of the present invention to provide a coaxial actuated medical device with the variable dimension core wire.
The elongated medical device system with a hollow tube has a movably actuated core wire therein adapted for use with a coaxially actuated medical device. The space between the central wire and the hollow tube is variable such that at different longitudinal positions, the radial space is different. One medical device system includes an elongated hollow tube with a plunge ground core wire movably disposed therein. Otherwise, the core wire may be spiral ground. Additionally, the core wire may have varying outer diameters over its lengths, none larger than the inside diameter of the tube. Further, the core wire may be formed by a plurality of braided wires. Alternatively, or in addition to, the elongated tube may be formed by a plurality of braided wires. In this embodiment, a solid core wire may be movably disposed in the braided tube or the core wire may likewise be braided by a second plurality of braided wires.
Further objects and advantages of the present invention can be found in the detailed description of the preferred embodiments when taken in conjunction with the accompanying drawings in which:
The present invention relates to a wire within a tube medical device system having variable core spaces therein. A variable diameter core wire is deployed in an elongated tube. In another embodiment, a braided tube is utilized (with or without the variable diameter core wire). The wire-in-a-tube configuration reduces the total surface contact in the lumen and hence reduces the total frictional force prohibiting movement of the core wire with respect to the tube. An associated medical device employing the reduced friction core wire and tube is also disclosed.
In another embodiment, the core wire may be built up with various coatings of low friction materials such as Teflon (PTFE). Small discrete lengths of shrink type PTFE or similar low friction material could be applied to a smaller mandrel or core wire. The areas of reduced diameter 12, 14 decrease the points of drag and contact between core wire 10 and the elongated hollow tube. FIG. 8 shows lengthy contact regions and
In a preferred embodiment, spiral tube tip body 42 is radio opaque and, in a working embodiment, is platinum-iridium, such that the health professional can locate the tip with the imaging system. The floppy tip 42 is not typically coated with lubricious coating.
Another technique to reduce the friction points between the core wire (or central wire) and the tube is to form tube 50 with a plurality of braided wires.
Additionally, the braided core wire 60 may be utilized in conjunction with the braided catheter tube or cannula 50. Implementing the braided tube or cannula in
The claims appended hereto are meant to cover modifications and changes within the scope and spirit of the present invention. What is claimed is: