Patent Application
20060135948
The present invention generally relates to medical catheters and medical apparatuses involving medical catheters. The present invention more particularly relates to seals for guide members of Multi-Exchange catheters.
Cardiovascular disease, including atherosclerosis, is a leading cause of death in the U.S. The medical community has developed a number of methods and devices for treating coronary heart disease, some of which are specifically designed to treat the complications resulting from atherosclerosis and other forms of coronary arterial narrowing.
One method for treating atherosclerosis and other forms of coronary narrowing is percutaneous transluminal coronary angioplasty, commonly referred to as “angioplasty” or “PTCA.” The objective in angioplasty is to enlarge the lumen of the affected coronary artery by radial hydraulic expansion. The procedure is accomplished by inflating a balloon of a balloon catheter within the narrowed lumen of coronary artery.
In addition to PTCA, catheters are used for delivery of stents or grafts, therapeutic drugs (such as anti-vaso-occlusion agents or tumor treatment drugs) and radiopaque agents for radiographic viewing. Other uses for such catheters are well known in the art.
The anatomy of coronary arteries varies widely from patient to patient. Often a patient's coronary arteries are irregularly shaped, highly tortuous and very narrow. The tortuous configuration of the arteries may present difficulties to the physician in proper placement of a guidewire, and advancement of a catheter to a treatment site. A highly tortuous coronary anatomy typically will present considerable resistance to advancement of the catheter over the guidewire.
Therefore, it is important for a catheter to be highly flexible. However, it is also important for a catheter shaft to be stiff enough to push the catheter into the vessel in a controlled manner from a position far away from the distalmost point of the catheter.
Catheters for PTCA and other procedures may include a proximal shaft, a transition section and a distal shaft having a flexible distal tip. In particular, the catheters have a proximal shaft, which is generally rigid for increased pushability and a more flexible distal shaft with a flexible distal tip for curving around particularly tortuous vessels. The proximal shaft may be made stiff by the insertion of a thin biocompatible tube, such as a stainless steel hypotube, into a lumen formed within the proximal shaft. The transition section is the portion of the catheter between the stiffer proximal shaft and the more flexible distal shaft, which provides a transition in flexibility between the two portions.
With some types of catheter construction, when an increase in resistance occurs during a procedure there is a tendency for portions of the catheter to collapse, buckle axially or kink, particularly in an area where flexibility of the catheter shaft shifts dramatically. Consequently, the transition section is often an area where the flexibility of the catheter gradually transitions between the stiff proximal shaft and the flexible distal shaft. It is known in the art to create a more gradual flexibility transition by spiral cutting a distal end of the hypotubing used to create stiffness in the proximal shaft. Typically, the spiral cut is longitudinally spaced father apart at the hypotube proximal end creating an area of flexibility, and longitudinally spaced closer together at the hypotube distal end creating an area of even greater flexibility.
In a typical PTCA procedure, it may be necessary to perform multiple dilatations, for example, using various sized balloons. In order to accomplish the multiple dilatations, the original catheter must be removed and a second catheter tracked to the treatment site. When catheter exchange is desired, it is advantageous to leave the guidewire in place while the first catheter is removed to properly track the second catheter.
Two types of catheters commonly used in angioplasty procedures are referred to as over-the-wire (OTW) catheters and rapid exchange (RX) catheters. A third type of catheter with preferred features of both OTW and RX catheters, which is sold under the trademarks MULTI-EXCHANGE, ZIPPER MX, ZIPPER, MX and/or MXII, is discussed below. An OTW catheter's guidewire lumen runs the entire length of the catheter and may be positioned next to, or enveloped within, an inflation shaft. Thus, the entire length of an OTW catheter is tracked over a guidewire during a PTCA procedure. A RX catheter, on the other hand, has a guidewire lumen that extends within only the distalmost portion of the catheter. Thus, during a PTCA procedure only the distalmost portion of a RX catheter is tracked over a guidewire.
If a catheter exchange is required while using a standard OTW catheter, the user must add an extension wire onto the proximal end of the guidewire to maintain control of the guidewire, slide the catheter off of the extended guidewire, slide the new catheter onto the guidewire and track back into position. Multiple operators are required to hold the extended guidewire in place while the original catheter is exchanged in order to maintain its sterility.
A RX catheter avoids the need for multiple operators when exchanging the catheter. With a rapid exchange catheter, the guidewire runs along the exterior of the catheter for all but the distalmost portion of the catheter. As such, the guidewire can be held in place without an extension when the catheter is removed from the body. However, one problem associated with RX catheters is the guidewire, and most of the catheter, must be removed from the body in order to exchange guidewires. Essentially the procedure must then start anew because both the guidewire and the catheter must be retracked to the treatment site. An OTW catheter, with the guidewire lumen extending the entire length of the catheter, allows for simple guidewire exchange.
A balloon catheter capable of both fast and simple guidewire and catheter exchange is particularly advantageous. A catheter designed to address this need is sold by Medtronic Vascular, Inc. of Santa Rosa, Calif. under the trademarks MULTI-EXCHANGE, ZIPPER MX, ZIPPER, MX and/or MXII (hereinafter referred to as the “MX catheter”). An MX catheter is disclosed in U.S. Pat. No. 4,988,356 to Crittenden et al.; co-pending U.S. patent application Ser. No. 10/116,234, filed Apr. 4, 2002; co-pending U.S. patent application Ser. No. 10/251,578, filed Sep. 18, 2002; co-pending U.S. patent application Ser. No. 10/251,477, filed Sep. 20, 2002; co-pending U.S. patent application Ser. No. 10/722,191, filed Nov. 24, 2003; and co-pending U.S. patent application Ser. No. 10/720,535, filed Nov. 24, 2003, all of which are incorporated by reference in their entirety herein.
The MX catheter includes a catheter shaft having a guidewire lumen positioned side-by-side with an inflation lumen. The MX catheter also includes a longitudinal cut that extends along the catheter shaft and that extends radially from the guidewire lumen to an exterior surface of a catheter shaft. A guide member through which the shaft is slidably coupled cooperates with the longitudinal cut such that a guidewire may extend transversely into or out of the guidewire lumen at any location along the longitudinal cut's length. By moving the shaft with respect to the guide member, the effective over-the-wire length of the MX catheter is adjustable.
The guidewire is threaded into a guidewire lumen opening at the distal end of the catheter and out through the guide member. The guidewire lumen envelopes the guidewire as the catheter is advanced into the patient's vasculature while the guide member and guidewire are held stationary. Furthermore, the indwelling catheter may be removed by withdrawing the catheter from the patient while holding the proximal end of the guidewire and the guide member in a fixed position. When the catheter has been withdrawn to the point where the distal end of the cut has reached the guide member, the distal portion of the catheter over the guidewire is of a sufficiently short length that the catheter may be drawn over the proximal end of the guidewire without releasing control of the guidewire or disturbing its position within the patient.
During some catheter advancing and retracting processes, including a catheter exchange, it can be difficult to hold the guidewire proximal end and the guide tool in a fixed position with one hand, while retracting or advancing the catheter with the other hand. Once the guidewire is positioned in a desired region of the patient's body, it is important to maintain that guidewire position to enable the present catheter or a replacement catheter to quickly advance through an occluded or tortuous vein.
While the MX catheter provides many advantages over RX catheters, like an RX catheter, the proximal shaft may not be completely secured in the hemostasis valve. For example, in a typical dye injection the physician may pull a slight negative pressure to ensure that no air bubbles are in the system. However, if the physician pulls a very heavy vacuum, there remains the possibility that air may enter the patient through the hemostasis valve if it is not sealed sufficiently. Similarly, RX catheters used with passive/active gaskets in a hemostasis valve may also be susceptible to air entering if the gasket is not closed properly and a very heavy vacuum is drawn.
Accordingly, it is desirable to provide an apparatus that can reduce or eliminate the opportunity for unwanted air aspiration. In addition, it is desirable to provide such an apparatus that does not slow down guidewire insertion or other medical processes involving the catheter. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
A system is provided to exchange a catheter and/or a guidewire. The system includes a catheter and a guide member. The catheter includes a lumen extending through the shaft and sized to receive the guidewire, and a longitudinal guideway enabling transverse access from the shaft exterior surface to the lumen. The guide member includes a housing, a catheter passageway extending through the housing and adapted to slidably receive the catheter, a guidewire passageway extending from one end of the housing into the catheter passageway and including a tube adapted to merge the guidewire transversely through the guideway and into the first lumen, and a user-activated device positioned in the guidewire passageway and including a clamping body adapted to clamp the guidewire and thereby secure the guidewire in the guidewire passageway.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
FIGS. 2A-D are cross sectional views of a catheter at points A-A, B-B, C-C, and D-D illustrated in
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
The present invention is used with an MX catheter, an exemplary embodiment of which is illustrated in
The present invention includes a guide member for the MX catheter 12.
The catheter proximal shaft 22 described above can be modified to suit various needs. For example, the proximal shaft can be a tri-lumen shaft to provide passage for various drugs, fluids, wires, or other necessary compositions or equipment. Further, the proximal shaft may be oval, circular, or other suitable shape.
Returning to
Turning now to
The guide member main body 98 includes a catheter passageway 88 extending longitudinally in a generally straight line from the guide member proximal end 92 to the guide member distal end 94. A guidewire passageway 80 extends distally from the guide member proximal end 92 through an entrance port 82 into a tube 86 and then into the catheter guidewire lumen 30, although the catheter is not depicted in
The entrance port 82 is configured to mate with a conventional wire introducer tool and is tapered to aid in loading such a tool. The tube 86 may vary in its length, although in an exemplary embodiment of the invention the tube 86 extends through the catheter guidewire lumen 30 approximately thirty-five millimeters past the guide member distal end 94. The tube 86 may be formed from a flexible material such as a polyimide, and particularly the tube region that extends through the catheter guidewire lumen 30. In one embodiment of the invention the tube region that introduces the guidewire 14 into the guidewire lumen 30 may be substantially rigid to provide the necessary support for the guidewire 14.
The guide member 10 is made of blends of polyamides and polyolefins in an exemplary embodiment of the invention. Other exemplary materials include ceramics, metals such as stainless steel, and other polymers such as polyamides and liquid crystal polymers. Lubrication additives such as polyethylene micro-powders, fluoropolymers, silicone-based oils, fluoro-ether oils, molybdenum disulphide, and polyethylene oxide may be included. Reinforcing additives such as nano-clays, graphite, carbon fibers, glass fibers, polyesters, polyketones, polyimides, polysulphones, polyoxymethylenes, polyolefins, cross-linked polyolefins may also be included, along with compatibilizers based on polyolefins, such as grafted polyolefins, ceramics, and metals.
An exemplary guide member operation will now be described, although the procedures in the following description clearly set forth only one of many operations enabled by the guide member 10. After the guidewire 14 and a guide catheter (not shown) are inserted into a patient, the catheter 12 is inserted with a backloading operation. The guidewire 14 is inserted into the catheter distal end 18 and threaded proximally through the guidewire lumen 30 until the guidewire tube 86 captures the guidewire proximal end and directs it into the passageway 80 and then out of the guide member proximal end 92. This procedure can be accomplished with the guide member 10 adjacent the catheter guideway distal end. As the distal shaft 20 enters the patient, the guide member 10 will reach the hemostatic valve (not shown). The guide member 10 is not intended to enter the valve and is seated adjacent to the valve. The proximal shaft 22 is then advanced through the guide member, and the keel 84 engages the catheter guideway 32. After the catheter 12 is inserted, the hemostatic valve may be closed down on the catheter shaft at a region that is distal to the guide member 10. Since the tube 86 extends in to the distal shaft 20, it is subjected to the valve clamping force. If a wire change is required, one simply withdraws the guidewire 14 from the guide member 10 as the guide member 10 is seated against the valve and as the proximal shaft 22 remains in the patient. A new guidewire is then inserted into the catheter through the passageway 80. If a catheter exchange is required, one simply holds the guidewire 14 in place and begins moving the proximal shaft 22 proximally through the guide member. Another catheter may then be backloaded onto the guidewire 14 and introduced into the patient as described above.
In order to overcome the potential for air aspiration through the guidewire lumen 30 at the catheter proximal end, the passageway 80 is adapted to include a seal that prevents or minimizes air movement through the passageway.
The seal 40 includes a rigid cylindrical body 42 that secures the seal 40 in the guidewire entrance port 82. The cylindrical body 42 includes a threaded outer surface 43 that rotatably engages with threads 81 in the guidewire entrance port 82. The seal 40 also includes a tapered tip 44 that is formed from an elastomer material. The tip 44 has an outer surface in the form of a truncated cone. When the seal 40 is rotated in a tightening direction, the seal can be secured in the guidewire entrance port 82 until the tip 44 abuts a tapered tube entrance 83 as illustrated in
If a user wishes to completely eliminate airflow through the opening 46 or to clamp the guidewire in a desired position, the seal 40 can be further rotated in a tightening direction. Further tightening causes the elastomer material in the tip 44 to change shape and constrict the opening 46 around the guidewire 14. The seal 40 can be rotated until the guidewire 14 is tightly secured in its position, and a substantially airtight seal is provided around the guidewire 14. Likewise, if a user wishes to unclamp the guidewire, the seal 40 can be rotated in a loosening direction until the elastomer material in the tip 44 retains its original shape and the opening 46 retains its original diameter.
The seal 50 is depicted in
As with the tapered seal 40, the compression seal 50 is formed from an elastomer material that changes shape when compressed to constrict the guidewire opening 56, and retains its original shape when the compression force is removed. A tightening tool 52 includes a threaded rigid cylindrical body that secures the seal 50 in the guidewire entrance port 82. The cylindrical body 52 includes a threaded outer surface 53 that rotatably engages with threads 81 in the guidewire entrance port 82. When the tool 52 is rotated in a tightening direction, the tool 52 compresses the seal 50 in a primarily longitudinal direction. The longitudinal compression causes the seal to expand in a lateral direction. The lateral expansion causes the guidewire opening 56 to constrict, forming a substantially airtight seal with the guidewire 14 and securing the guidewire 14 in place. When the tool 52 is rotated in a loosening direction, the seal 50 retains its original shape.
Referring now to
During guidewire advancement and retraction, the flaps 67 are spread apart enough to allow a substantially frictionless guidewire pathway. The flaps 67 are biased in a separated position, but still substantially limit or prevent airflow into the guidewire passageway 80 during guidewire advancement. The guidewire can be secured in place by rotating the threaded body 62 in a tightening direction, causing the flaps 67 to contact the tube entrance 83 and be pressed around the guidewire 14. In the tightened position, the flaps 67 secure the guidewire in place and also further provide an airflow seal. The flaps 67 return to their biased separated position when the threaded body 62 is rotated in a loosening direction.
The above descriptions of various seals include the use of a rotatable cylindrical body that is threadedly engaged with the guidewire entrance port 82 to provide a user with ease and efficiency in the process of clamping or freeing the guidewire and limiting airflow through the opening 46. However, it is within the purview of the invention that the seal 40 and any of the other seals described herein can be secured and manipulated by a user using any suitable conventional clamp or securing device or material.
The seal 60 is secured in the guidewire port 82 using the threaded body 62 or any suitable securing mechanism. With the seal 60 in place, the actuating button 77 is configured to be pressed to a locking position such that a first end 79 of the button presses one of the flaps 67a toward an opposing flap 67b to clamp the guidewire 14 and provide a substantially airtight seal with the guidewire 14. The button 77 can be equipped with a hook 78 or other structure to latch the button 77 in the locking position in an exemplary embodiment of the invention. The hook 78 can engage with a tab 89 or any other structure that is integral with or otherwise combined with the guide member 10. To release the button 77 from the locking position, the user need only press the button 77 again and allow the hook to disengage with the tab.
In an embodiment similar to that depicted in
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
