Abstract:
A method and apparatus for placing a medical agent, such as an embolic coil into a vessel, or aneurysm, by utilizing a stabilizing catheter to retain or support a medical agent deployment device.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention concerns a novel method and apparatus for placing a medical agent into a vessel of the body, and in particular concerns a novel method for placing embolic coils within an aneurysm of the brain.  
         [0003]     2. Description of the Prior Art  
         [0004]     The use of embolic coils placed within an aneurysm for treating the aneurysm within the brain is well known. Various devices are known for delivering embolic coils through the patient&#39;s vessel to the aneurysm. Typically these embolic coils, which generally take the form of helically wound coils, or random wound coils, are carried by a coil deployment device which serves to introduce the coils into the aneurysm. The coils are then released by the coil deployment device using one of various types of release mechanisms.  
         [0005]     An example of such a coil deployment device is disclosed in U.S. Pat. No. 6,113,622 entitled, “Embolic Coil Hydraulic Deployment System”, issued Sep. 5, 2000 and assigned to the same assignee as the present patent application. The disclosure of this patent is incorporated herein and made a part of this application. It has been found to be difficult to place these coils in the exact desired position because of the relative lack of stability of the deployment device within the vessel during the introduction of the embolic coil to an aneurysm. An example of a delivery system used to stabilize a coil deployment device is disclosed in U.S. patent application Ser. No. 09/878,530, entitled “Delivery System Using Balloon Catheter”, filed Jun. 11, 2001 and assigned to the same assignee as the present patent application. The disclosure in this patent application is incorporated by reference and is made a part of the subject patent application.  
         [0006]     It is, therefore, an object of this invention to provide a method for placing embolic coils in a relatively precise manner by the use of a stabilizing delivery catheter.  
         [0007]     Another object of the present invention is to provide a method for placing embolic coils within an aneurysm of the brain, which system is relatively simple in use for the physician.  
         [0008]     A further object of the present invention is to provide a method for delivering medical agents such as diagnostic or therapeutic agents, and other medical agents by the use of a delivery catheter in a relatively simple, efficient and stable manner.  
         [0009]     A still further object is to provide a delivery catheter which enables the delivery of embolic coils within an aneurysm in a relatively simple, efficient and stable manner.  
         [0010]     Another object of the present invention is to provide a delivery catheter which may be utilized to deliver embolics, diagnostic, and therapeutic agents by way of a delivery lumen.  
         [0011]     A further object of the present invention is to provide a delivery catheter that is relatively simple in construction.  
         [0012]     Other objects of the present invention will become apparent from the following description.  
       SUMMARY OF THE INVENTION  
       [0013]     In accordance with one aspect of the present invention, there is provided a method for placing an embolic coil into an aneurysm. The method includes the use of a delivery catheter having a proximal section, a distal section and an intermediate section which is formed from a very flexible polymeric material. The catheter includes a first lumen and a second lumen having a side opening at a location within the intermediate section of the delivery catheter. The catheter also includes a pre-shaped retaining wire which extends through the first lumen for shaping the intermediate section into a generally U-shaped configuration. The method includes the steps of inserting a straightening wire into the second lumen of the catheter to cause the intermediate section of the catheter to become relatively straight, introducing the delivery catheter into the vessel of a patient to generally align the side opening with an aneurysm, withdrawing the straightening wire from the second lumen to cause the intermediate section of the delivery catheter to return to the U-shaped configuration at a location proximal to the aneurysm to thereby cause the side opening to move to a position adjacent to the aneurysm, introducing an embolic coil deployment system into the proximal end of the delivery catheter through the second lumen and then through the side opening into the aneurysm. The method also includes the steps of delivering the embolic coil into the aneurysm with the coil deployment system, withdrawing the embolic coil deployment system from the delivery catheter, again inserting the straightening wire into the second lumen of the catheter to cause the intermediate section to become relatively straight, and thereafter withdrawing the delivery catheter from the vessel of the patient.  
         [0014]     In accordance with the present invention there is also provided a method for placing a medical agent within a vessel. The method utilizes a delivery catheter having a proximal section, a distal section and an intermediate section which is formed of a polymeric material which is relatively flexible, and in which the intermediate section is normally shaped in a generally U-shaped, or bowed, configuration. In addition, the catheter has a first lumen and a second lumen having a side opening at a location within the intermediate section of the delivery catheter. The method includes the steps of inserting a guidewire into the second lumen of the catheter to thereby cause the intermediate section of the catheter to straighten, introducing the catheter into the vessel of a patient to generally align the side opening at a preselected position within the vessel, withdrawing the guidewire to thereby permit the intermediate section of the catheter to straighten, introducing a medical agent deployment device into the second lumen of the delivery catheter and through the side opening to deliver a medical agent at the preselected position, reinserting a guidewire into the second lumen of the delivery catheter to thereby again cause the intermediate section of the catheter to straighten, and thereafter withdrawing the delivery catheter from the vessel of the patient.  
         [0015]     In accordance with still another aspect of the present invention, the medical agent takes the form of a diagnostic agent, a therapeutic agent or such device such as an embolic coil.  
         [0016]     In accordance with still another aspect of the present invention there is provided a method for placing an embolic coil into an aneurysm. The method utilizes a delivery catheter which has a proximal section, a distal section and an intermediate section which is formed from a very flexible polymeric material. The intermediate section is normally shaped into a generally U-shaped, or bowed configuration. The catheter also includes a first lumen and a second lumen having a side opening at a location within the intermediate section of the delivery catheter. The method also incorporates a coil deployment device which includes an elongated flexible deployment catheter having a lumen extending therethrough and having a distal section being formed of a material of a durometer which exhibits the characteristics that when a fluid pressure is applied to the lumen of the deployment catheter the walls of the distal section expand outwardly. The coil deployment device in addition includes an embolic coil which is disposed in fluid tight engagement within the lumen o the distal section of the device. In addition, the coil deployment device includes a source of pressure coupled to the proximal section of the device for applying a fluid pressure to the lumen of the coil deployment device. The method includes the steps of inserting a straightening wire into the second lumen of the catheter to cause the intermediate section of the catheter to become relatively straight, introducing the delivery catheter into the vessel of a patient to generally align the second opening with an aneurysm, withdrawing the straightening wire from the second lumen of the delivery catheter to cause the intermediate section to return to the U-shaped configuration at a location proximal to the aneurysm to thereby cause the side opening to move to a position adjacent the aneurysm. The method also includes the steps of introducing the embolic coil deployment device into the proximal end of the delivery catheter through the second lumen and through the side opening into the aneurysm, applying a pressure with said source of pressure to the lumen of the deployment device to thereby cause the walls of the distal section of the deployment device to expand and release the embolic coil, withdrawing the embolic coil deployment device from the delivery catheter, again inserting the straightening wire into the second lumen of the catheter to cause the intermediate section to become relatively straight and thereafter withdrawing the delivery catheter from the vessel of the patient. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a partial sectional view of a delivery catheter constructed in accordance with the principles of the present invention;  
         [0018]      FIG. 2  is a partial sectional view of a vascular occlusive coil deployment system that may be used with the delivery catheter of  FIG. 1 ;  
         [0019]      FIG. 3  is a side elevational view of the delivery catheter of  FIG. 1  in use to delivery an embolic coil to an aneurysm;  
         [0020]      FIG. 4  is a cross-sectional view of the catheter of  FIG. 3 , taken along the plane of the line  5 - 5 ′ of  FIG. 3 ;  
         [0021]      FIG. 5  is a cross-sectional view of the catheter of  FIG. 3 , taken along the plane of line  5 - 5 ′ of  FIG. 3 ; and,  
         [0022]      FIGS. 6 through 9  are diagrammatic sequential views of a method of placing embolic coils in accordance with an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]      FIG. 1  generally illustrates the construction of a preferred embodiment of the delivery catheter of the present invention which generally comprises a dual lumen catheter  10  having a “Y” connector  12  coupled to the proximal end of the catheter. More particularly, the dual lumen catheter includes a first lumen  14  and a second lumen  16 . The second lumen  16  extends from the proximal end of the catheter to the distal end of the catheter and also communicates with a lumen  18  which extends from the distal end to the proximal end of the “Y” connector  12 . As illustrated, a side opening  20  extends from the second lumen  16  through the side wall of the catheter at a position which is slightly proximate the distal tip of the delivery catheter  10 . This side opening, as will be subsequently explained in more detail, serves to permit the introduction of an embolic coil deployment device into an aneurysm for placement of an embolic coil into the aneurysm.  
         [0024]     As further illustrated in  FIG. 1 , the first lumen  14  and a second lumen  16  extend through the delivery catheter  10 . In addition, the proximal end of the first lumen  14  and the second lumen  16  communicate with passageways in the “Y” connector  12  and extend out of the side port  22  and the proximal end respectively of the “Y” connector  12 .  
         [0025]     While the delivery catheter  10  may be constructed of various flexible materials including various polymers, preferably, the catheter  10  is formed in three different sections of materials having different durometers and different polymer compositions. The proximal section of the catheter  23 A, designated as “A”, is preferably formed of a nylon material having a durometer of about 75 D and extends for a length of about 100 centimeters. The intermediate section  23 B, designated as “B”, is preferably formed of a pebax material having a durometer of about 40 D and is generally about 40 centimeters in length, and the distal section  23 C of the catheter, designated as “C”, is preferably formed of a pellethane material having a durometer of about 80 A and extends for a length of about 10 centimeters. With this construction the catheter is sufficiently flexible to be delivered through the various tortuous vessels of the human brain but at the same time provides sufficient rigidity or “back-up” support for introducing the catheter into and through these vessels. This construction also makes possible the ease of deflection, or bowing, of the intermediate section  23 B.  
         [0026]     As may be seen, the delivery catheter also includes a pre-shaped wire  23  which is disposed in the first lumen  14 . The wire  23  is bent, or bowed, in the region of the intermediate section to thereby cause the intermediate section to be bowed thereby causing the side opening to be moved laterally away from the center line of the catheter.  
         [0027]      FIG. 2  illustrates a hydraulic occlusive coil deployment device  100  which is comprised of a hydraulic injector, or syringe,  102 , coupled to the proximal end of a positioning catheter  104 . An embolic coil  106  is disposed within the lumen at the distal section  108  of the catheter. The proximal end of the coil  106  is tightly held within the lumen of the distal section  108  of the catheter  104  until the deployment device is activated for release of the coil. As may be seen, the syringe  102  includes a threaded piston  110  which is controlled by the handle  112  for infusing fluid into the interior of the catheter  104 . Also, as illustrated, the catheter  104  includes a winged hub  114  which aids in the insertion of the catheter.  
         [0028]     The embolic coil  106  may take various forms and configurations, and may even take the form of a randomly wound coil. Preferably, the distal section of the coil deployment device  100  is formed of a polymeric material with a relatively low durometer which exhibits the characteristic that, when a fluid pressure of approximately 300 psi is applied to the interior of the catheter, the walls of the distal section  108  expand radially, somewhat similar to the action of a balloon inflating, to thereby release the proximal end of the coil  106 . Reference is made to the above-mentioned U.S. Pat. No. 6,113,622 for a more detailed description of the hydraulic occlusive coil deployment device  100 .  
         [0029]      FIG. 3  illustrates in detail the delivery catheter  10  which has been inserted into a blood vessel  26  of the brain in order to place an embolic coil  106  into an aneurysm  28 .  FIGS. 4 and 5  illustrate cross-sections taken through the delivery catheter  10  at locations indicated by  4 - 4 ′ prime and  5 - 5 ′, respectively, shown in  FIG. 3 .  
         [0030]     More particularly,  FIG. 4  in conjunction with  FIG. 3  illustrates the location where the pre-shaped wire  23  is bowed to cause the delivery catheter to be normally shaped in a generally U-shaped configuration at the intermediate section  23 B of the catheter. Also illustrated in  FIG. 4  is an end view of the embolic coil deployment device which extends through the side opening  20  of the catheter  10 .  FIG. 5  illustrates a sectional view of the delivery catheter  10  with the pre-shaped wire  23  disposed in the first lumen  14 .  
         [0031]     Reference is made to  FIGS. 3 and 6  through  9  for an understanding of the operation of the delivery catheter used in conjunction with the embolic coil deployment device  100 . As illustrated in  FIG. 6 , the delivery catheter is inserted into a vessel, over a stiffening guidewire  32 , and is positioned such that the side opening  20  is adjacent to an aneurysm  28 . The guidewire  32  is then removed and as illustrated in  FIG. 7 , the delivery catheter  10  deflects, or bows, in the region where the side opening  20  is located to thereby cause the side opening to essentially mate with the opening of the aneurysm  28 . Once the side opening  20  has been positioned at the mouth of the aneurysm  28 , the embolic coil deployment device  100  may then be inserted through the second lumen and then out of the side opening  20  and into the aneurysm  28  as illustrated in  FIG. 8 . Then the embolic coil  106  may be placed into the aneurysm and released from the distal end of the deployment device  100 .  
         [0032]     The deployment device  100  may then be removed and this process may be repeated until such time as sufficient coils have been placed into the aneurysm. When the aneurysm  28  has been sufficiently filled with embolic coils, the coil deployment device may be removed from the delivery catheter. Thereafter, the stiffening guidewire  32  may be inserted into the second lumen  16  to thereby cause the delivery catheter to straighten within the vessel. Once the catheter has straightened, the catheter may be easily withdrawn from the vessel and from the body of the patient.  
         [0033]     Alternatively, the delivery catheter may be constructed with a shape retaining wire disposed in the first lumen  14  as opposed to the pre-shaped wire  23 , and in this case the physician may pre-shape the intermediate section  23 B into a generally U-shaped configuration prior to use.  
         [0034]     In still another alternative construction, the delivery catheter may be a single lumen catheter having neither a pre-shaped wire  23  nor a shape retaining wire, but the catheter body is formed of a shape retaining polymer which may be heat set to form a U-shaped intermediate section, either when the catheter is manufactured or by the physician prior to use by the physician.  
         [0035]     As may be appreciated, with the present invention it is possible to stabilize the delivery catheter at a position where the side opening of the delivery catheter is adjacent to the aneurysm. Embolic coils may be delivered through the side opening of the delivery catheter directly into the aneurysm with relatively good precision. With this system it is possible to fill an aneurysm with a plurality of embolic coils in very short order without the loss of coils into the main blood vessel, or other vessels within the body. These and other advantageous of this invention will become more apparent from an understanding of the invention as claimed.  
         [0036]     A novel system and method have been disclosed in which an embolic coil, or coils, may be securely placed within an aneurysm with a delivery catheter which is stabilized. Although an illustrative embodiment of the invention has been shown and described, it is to be understood that various modifications and substitutions may be made by those skilled in the art without departing from the spirit and scope of the present invention.  
         [0037]     Further, in addition to the delivery of embolic coils, the system may be utilized to deliver other medical agents such as diagnostic or therapeutic agents of various types including liquid embolic materials. Other modifications may be made which would be within the spirit and the scope of the following claims.