Drug Delivery Catheters That Attach to Tissue and Methods for Their Use
A system and method for delivering a drug to a target site within a patient's body. The system and method include a steerable guide catheter and a drug delivery catheter. The steerable guide catheter has a first extension tube and a second extension tube that are joined together and form a shoulder. The delivery catheter has a distal docking segment and a proximal docking segment. The guide catheter is inserted into the patient's body, then the delivery catheter is inserted into the guide catheter. The distal docking segment engages the first extension tube, the proximal docking segment engages the second extension tube, and the shoulder limits the distance the delivery catheter can be inserted into the guide catheter. Also, once the delivery catheter is inserted it can be rotated to attach the helical tip to the target site. The guide catheter also includes a steering mechanism as well as a friction mechanism which controls the tension on the steering mechanism. The delivery catheter also includes two luer fittings, each having its own lumen.
This application is a continuation of U.S. patent application Ser. No. 11/439,628, filed May 23, 2006, which is a continuation of U.S. application Ser. No. 10/353,233, filed Jan. 27, 2003, now U.S. Pat. No. 7,048,711, which is a continuation of U.S. application Ser. No. 09/746,986 filed Dec. 22, 2000, now U.S. Pat. No. 6,511,471.FIELD OF THE INVENTIONS
The inventions described below relate to site-specific delivery of therapeutic agents, structures and catheter systems to achieve site-specific delivery of therapeutic agents, and means for implanting and using these systems to enable delivery of therapeutic agents to the body.BACKGROUND OF THE INVENTIONS
We have been developing catheter systems which enable injection of therapeutic agents into the heart in very precise doses and locations within the heart. The catheter systems use a helical needle, mounted on the distal end of a catheter, to secure the device to the heart wall prior to and during injection. With the helical needle, the injection site can be chosen, mechanically engaged, viewed and confirmed, and maintained for relatively long intraoperative periods or chronically. The helix prevents dislodgment of the needle during injection or during an extended period of injections. Rudimentary mechanisms have been proposed for insertion and rotation of the helix, which must be accomplished from the proximal end of the catheter system. The devices described below provide mechanisms for inserting and driving the drug delivery catheter into the heart, as well as connecting the requisite drug reservoirs to the catheter.SUMMARY
Several embodiments of catheter systems designed to facilitate drug delivery into the heart are described below. The catheter systems include a steerable guide catheter and a drug delivery catheter designed for use together. The drug delivery catheter is inserted through the lumen of the guide catheter, and its handle is dockable within the handle of the guide catheter. Integrated design of the drug delivery catheter with the steerable guide catheter provides for a keyed or matched assembly of the device which provides for limited or controlled extension of the drug delivery catheter tip from the guide catheter tip. In one embodiment, the drug delivery and steerable guide mechanisms are integrated in a single piece handle, and distensible tubing on the proximal end of the drug delivery catheter allows rotation of the drug delivery catheter tube relative to the guide catheter tube and Luer fitting which are in fluid communication with the drug delivery catheter.
New concepts for delivering agents for the treatment of heart failure, ischemia, arrhythmias, and restenosis are disclosed. The main embodiment consists of transvenous or transarterial catheter delivery techniques for delivering agents directly to a chosen site within the heart at a depth within the heart tissue. Hollow helical delivery devices, needle delivery devices, and implantable controlled release matrices may be inserted such that metabolic agents, anti-ischemic agents, growth factors, antiarrhythmic agents, anti-inflammatory agents, gene therapy preparations, cells, cellular material and combinations of these agents may be delivered directly to the tissue that can benefit most from these agents. These systems have applicability in many areas of the body, particularly those that may be accessed via a body duct or vessel.
These drug delivery structures may be made from drastically different materials depending upon whether the device is to be used chronically or acutely. For example, metal components in the implantable embodiments, which are formed of a Platinum Iridium alloy consisting of ninety percent Platinum and ten percent Iridium, will typically be replaced with 316L surgical stainless steels in the acute embodiments. Likewise implantable grades of silicone and polyurethane will be replaced with polyurethanes, polyolefins, fluoropolymers, nylon, and the like in the acute uses of the devices. As a means of addressing this, the term catheter is used to describe both chronically and acutely implantable systems.
Again referring to
The devices are used together to infuse therapeutic agents to tissues in the body that are accessible through ducts or vasculature. The doctor inserts the steerable guide catheter through the femoral hemostatic sheath into the femoral vessel. The guide may or may not have a guidewire inside it. The guidewires are commercially available medical devices that help route catheters to their ultimate position in the body. They are commonly stainless steel or PTFE covered stainless steel coils that are 0.065″ in diameter or less and 90-180 centimeters in length. They come in varying stiffness and end shapes (straight or j-tipped). The steerable guide catheter is routed up the artery until it reaches the aortic arch. The doctor may advance and retract the guidewire during the installation as desired. The guide catheter can also be steered (curved) by the doctor by actuating the steering knob 28 during advancement. Once the distal tip of the guide gets to the aortic valve, the guidewire may be prolapsed into the ventricle. The steerable guide catheter is then advanced across the valve into the left ventricle over the guidewire and the guidewire is removed. Alternately, the steerable guide can be curved to its tight radius shape to 180 degrees of curvature or more and prolapsed across the aortic valve without the use of a guidewire. The doctor may choose to infuse radiopaque contrast agent through the guide at this time by hand or with a power injector to create a radiographic ventriculogram or x-ray picture of the shape and structures of the ventricle.
The drug delivery catheter tube 16 is now inserted into the steerable guide catheter 6 through the hemostatic adapter 25 until the tip of the delivery catheter is coincident with end of the steerable guide catheter. This position can be seen on the fluoroscopic monitors or can be indicated by marks on the proximal shaft of the delivery catheter. The steerable guide catheter 6 is now curved by actuation of the steering knob 28 and rotated by rotating the handle to position the delivery catheter tube 16 toward the tissue to be treated. (The thumbscrews 33 have been designed to limit the number of rotations that the doctor may make, to prevent over-penetration of the helical tip in the myocardium. If the doctor is not satisfied with initial placement, or wants to reposition the helical tip for additional treatment, the thumbscrews must be operated to withdraw to helical tip prior to another attempt to drive the helical tip into the heart). The delivery catheter tube 16 is then extended until the tip of the catheter touches the tissue to be treated. The surgeon rotates the thumbscrews 33 in the handle of the delivery catheter 8 and advances the helical tip 9 into the tissue to be treated. The surgeon may view the catheters under fluoroscopic or other real time imaging systems. He can infuse contrast through the side arm 26 of the hemostatic adapter around the delivery catheter tube 16 and toward the tissue of interest. He can infuse contrast agent from the end of the delivery catheter that is not embedded in the tissue through one of the stopcocks on the delivery catheter handle. The last alternative is to infuse tissue-compatible imaging agent through the lumen connected to the hollow helical needle and out of the tip of the needle itself. This last modality may allow the doctor to judge the vascularity of the tissue in the area as well as the depth of the helical tip by the rate at which the tissue takes away the contrast media. The doctor may also monitor the electrical signal obtained from a wire connected to the distal helical tip to confirm penetration of the myocardium.
Once the doctor is satisfied with the depth and location of the needle tip, the therapeutic agent is infused through the hollow helical needle. The doctor can control the volume, pressure, rate and amount of therapeutic agents delivered. Several therapeutic agents can be delivered in series. Flushing agent can be delivered before or after the therapeutic agent to change the distribution patterns. Other agents can be infused systemically preceding, concomitant, or following this treatment. Other agents can be delivered to the left ventricular free space through the second lumen in the delivery catheter or through the guide via the side arm of the hemostatic “Y”. Agents can be infused by hand with syringes of various sizes and volumes or using powered pumps or injectors.
After the delivery sequence is complete, the doctor rotates the delivery thumbscrews 33 and detaches the helical tip 9 of the delivery catheter 8 from the heart wall. At this time, the tip of the delivery catheter can be retracted into the steerable guide catheter 6 by moving the handles relative to one another. The guide may then be steered to another location by changing its curve with the steering knob 28 or rotating its handle. If another infusion is desired, the process is repeated for that site. Alternatively, the delivery catheter can be fully withdrawn from the body, the guide repositioned, the delivery catheter reinserted and another infusion given.
Another use of the side arm on the hemostatic “Y” is to drip saline or heparinized saline around the delivery catheter and through the guide catheter during use. This method is thought to minimize the chance of thrombus formation on the devices during extended procedures.
The mechanism that allows passage of the first extension 34 through the center of the handle while providing a centrally located steering knob is the “U”-shaped rocker or crank 38 that is mounted on pin 39 fixed to one of the handle halves (in this case, fixed to the inside surface 40 of the handle bottom). The U-shaped crank 38 is pinned to the housing half via the pin which is positioned off the central axis of the housing, displaced radially toward the handle outer edge. This provides an off-center rotational axis for the crank. The steering pullwire 41 of the steerable guide catheter is secured to the crank, with the attachment point displaced radially (across the radius of the handle) so that rotation of the crank about the pin causes longitudinal motion of the pullwire. The steering pullwire 41 is clamped to the U-shaped crank 38 under a setscrew 42 that is screwed into the crank.
The pullwire 41 may have a metal or polymer sleeve crimped, glued, or slid on its end to protect it from being crushed by the setscrew. The pullwire may be solid, stranded, coated, or wound and is typically constructed of stranded Kevlar, highly oriented polymer, or metal such as stainless steel and coated with fluoropolymer. The pullwire 41 is typically between 0.002 and 0.015 inches in diameter and preferably 0.006″ in diameter. The pullwire may be either round in cross section or flattened such as an oval, rectangle, or ribbon. As shown in
A friction knob 53 is attached to the outside side of the bottom handle half 54, and is secured to the crank with the pin 39 which is inserted through the bottom handle half 54. The user turns the friction knob 53 that is coupled to a flat friction plate 56 and the crank via the pin 39 inside of the handle 11 to increase or decrease the tension on the steering knob.
Referring again to
Preferably, the guide catheter tube 13 is comprised of an outer shaft and an inner tube, as shown in
To lock the guide catheter to the housing of the handle, the outer catheter shaft 58 may be joined to a mounting block 60. The mounting block may be any shape, and the receiving cavities 61 are keyed to the shape of the mounting blocks. When the handle halves are joined together, the mounting block is trapped in the cavities, and rotation in prevented. Preferably, the mounting block has a rectangular prism shape and the cavities in the housing halves are keyed to this shape. The constraint of the mounting block 60 by the handle cavities prevents rotation or translation of the outer catheter shaft 58 relative to the handles.
The covered coil assembly sits inside of a slotted cylinder or bushing 71 that spans the joint between the proximal grooved PTFE liner 59 and the distal section of the catheter. The slotted bushing is a stainless steel tube that has had a slot machined or ground into it to allow the pullwire 41 to move freely. The slotted bushing 71 is glued, welded, or bonded onto both the distal and proximal sections of the catheter, reinforcing this joint. The slotted bushing is typically 0.095 OD, 085ID, and 0.500″ in length with a 0.020″ wide slot entirely through its length.
Assembled over the bushing 71 on the distal portion of the catheter is the slotted deflection tube assembly. The deflection tube 70 consists of a round stainless steel or nitinol tube with a specific pattern of slots machined into it as shown in
Referring back to
The delivery catheter shown in
The handle 14 is typically constructed of machined, cast or molded engineering thermoplastic such as polycarbonate, urethane, ABS or the like. The handle is generally rounded so that the surgeon can easily rotate it. The outside diameter of the handle is typically 0.500 inches and is kept small to keep the weight and bulk of the device to a minimum. The handle has a flattened portion 91 machined or molded into it. The flattened portion 91 serves to increase the surgeon's grip on the device and allows the surgeon to count revolutions of the handle by touch rather than by sight when the device is in use.
The handle 14 is joined to one or more concentric docking segments 92 and 93 at the handle's distal end. The docking segments are typically thin-walled stainless steel, aluminum, PEEK, Pebax, urethane, or liquid crystal polymer tubes. Their outside diameter is sized to fit into the corresponding hole in the steerable catheter handle 11 and their mating tubes (the first extension tube 34 receives the distal docking segment 93 while the second extension tube 35 receives the proximal docking segment 92) in the steerable guide catheter while their inside diameters are large enough to allow the braided delivery catheter tube 16 to pass within them. The distal faces of the docking segments 92 and 93 may be radiused or chamfered to ease their insertion into mating parts. The docking segments 92 and 93 are typically 0.118″ in outside diameter, 0.065″ inside diameter and 4.6″ in length. The total length of the docking section is chosen to begin the docking process with the handle of the steerable guide catheter before or at the same time that the end of the delivery catheter will be exiting the outer guide. The length of the docking portion limits the amount of delivery catheter that can be extended from the distal end of the guide catheter when in use, in concert with the lengths of the outer guide and delivery catheter shafts. The docking segments also provide a transition in stiffness between the rigid handle and the flexible catheter shaft.
The proximal docking segment 92 is the more rigid section, and facilitates insertion of the drug delivery catheter into the outer guide or hemostatic “Y” adapter during use. The distal docking segment 93 is the more flexible portion of the strain relief, and serves to prevent kinking of the catheter shaft during handling by the physician, and also resists the crushing or clamping of the hemostatic-Y seal on the delivery catheter during use. This keeps the infusion lumens open while preventing blood loss from the devices during use. The smooth outer diameter of the strain relief allows easy sliding of the delivery catheter within the outer guide or hemostatic-Y and easy rotation in either the clockwise or counterclockwise directions while blood loss is prevented by the hemostatic-Y.
The outer shaft 97 of the delivery catheter tube 16 fits over the dual lumen tubing 94 and within the docking segments 92 and 93 and handle 14. It is typically a round, multi-durometer, stainless steel braid reinforced Pebax shaft with an outer diameter of 0.062″ and an inner diameter of 0.044″. The Pebax durometer typically changes from 75 D on the proximal end for good pushability to 63 D or 55 D or 35 D on the distal end for good bendability, steerability or tracking, as the case may be. The stainless steel braid reinforcement enhances the ability of the shaft to transmit torque from the handle to the distal end of the device and to elastically bend around curves without kinking or collapsing.
The outer shaft 97 of the drug delivery catheter tube 16 is joined to a flexible coil about 4″ proximal to the distal end of the device. The shaft and coil are joined by gluing, bonding, welding, soldering, or crimping them both to a joining sleeve or bushing. The joining sleeve or bushing is typically a thin-walled stainless steel tube. Its typical dimensions are 0.042″ outside diameter by 0.038″ inside diameter by 0.400″ in length. It may alternately be constructed of a thermoplastic, thermoset or elastomeric polymer. Its length is minimized to limit the stiffness of the joint while maintaining adequate bending, torsional, compression, and tensile strength to the joint between the braided Pebax tube and the distal coil shown in
Referring again to
The coil 98 terminates at the distal end of the device coincidentally with the end of the dual lumen tubing 94. The end of the double-d tubing 94 can be bonded into the end of the coil 98 for reliability. The larger lumen of the double-d tubing 94 is left open at this distal end for infusion of fluid from the side arm 31 on the proximal handle. The smaller lumen is connected to the hollow helical tip 9 so that central needle hub is in fluid communication with the lumen of the hollow helical tip.
The hollow helical tip 9 consists of stainless steel hollow tubing wound into a specific shape and sharpened. The size of the helical tip 9 is chosen to allow an adequate rate of infusion of therapeutic liquid through it and reliable anchoring in tissue, especially cardiac tissue. The proximal end of the helical tip 9 is straightened and glued or bonded into the smaller lumen of the double-d tubing 94, typically with cyanoacrylate, epoxy, or urethane adhesive. The tubing used to construct the helical tip 9 is typically 0.016″ OD and 0.008″ ID stainless steel hypodermic tubing. The helical tip 9 is wound into a right-handed (clockwise) spiral with an outer pitch diameter of 0.048″. The spacing between the turns of the helical tip 9 is typically 0.051″. The helical tip 9 typically consists of three or more full turns, and is generally 0.350″ in usable length. The distal open end of the helical tip 9 is sharpened into a point to ease insertion into tissue.
As shown in
The coiling of the dual lumen tubing allows the tubing to take up variations in length when the device is being used. The double-d tube is typically coiled into a helical shape with an outside diameter of 0.250″ and a coil length of 1 inch. The coiling is accomplished by winding and heat-treating on a mandrel during manufacturing. The thumbscrew is the control used by the surgeon to rotate the catheter tube 16 and distal helical tip 9. One of the cylindrical ends of the thumbscrew 108 has an external thread 115 that mates with an internal thread in the housing. Rotation of the thumbscrew 108 in a clockwise direction causes the thumbscrew 108 to move forward (which drives the catheter tube 16 forward while it rotates). Rotation in the counterclockwise direction causes the catheter tube 16 to move backward. The thumbscrew 108 is accessible to the surgeon through windows on both the top and bottom housings of the handle. The length of the threads 115, size of the thumbscrew body, and size of the windows in the upper and lower housings control the amount of forward and backward travel of the catheter tube 16 relative to the handle. This interaction controls the number of turns that the distal helical tip 9 can be screwed into tissue. The pitch of the threads in the housing and on the thumbscrew controls the rate at which the catheter is driven forward or backward and may be matched to the pitch of the distal helical tip 9 for a 1 to 1 relationship between thumbscrew and helical tip 9.
The drug delivery catheter is inserted into the pre-installed steerable or fixed guide through the hemostatic “Y” adapter on the back of the guide. Infusion syringes or lines may be attached to the Luer fittings at the proximal end of the handle at any time. Translation of the delivery catheter handle relative to the guide handle causes the tip of the delivery catheter to advance closer to the tip of the guide. When the rigid strain relief of the delivery catheter enters the hemostatic “Y”, the handles of the two devices become docked or locked in bending. They may still be translated and rotated relative to one another, but they are rigid in bending in all degrees of freedom.
The guide distal tip is steered into place, the delivery catheter is extended from the distal tip of the guide by translating the handles relative to one another, and the helical tip is anchored in tissue by turning of the thumbscrew in the clockwise direction. In this embodiment, the handle of the delivery catheter is not rotated to anchor the helical tip in the tissue; only the thumbscrew is rotated. Inside the handle, the coiled double-d tubing expands and contracts to take up this motion between the rotating and advancing helical tip and the stationary infusion stopcocks. After anchoring in tissue, the surgeon may deliver radiopaque contrast medium to confirm location from the lumen that ends at the base of the helical tip, or through the side arm of the hemostatic “Y” and through the guide around the delivery catheter, or infuse therapeutic agent into the anchored tissue through the sharpened helical tip. When delivery is complete, the physician removes the helical tip from the tissue and moves it to another location or removes the system from the body.
This thumbscrew 120 is permanently attached to the drug delivery tube 121 (which is similar to the drug delivery catheter tube 16 of the earlier Figures, but in this embodiment is integrally attached to the guide catheter). Moving the sliding grip 117 forward translates the drug delivery tube 121 and thumbscrew 120 forward relative to the steerable outer tube 122. The thumbscrew 120 is accessible from either side of the handle, and the cutout 123 is provided on both sides of the sliding grip 117. When the thumbscrew 120 is rotated in the clockwise direction (when viewing the handle from the back), the threads drive the thumbscrew 120 forward relative to the sliding grip 117. The thumbscrew then rotates and translates the drug delivery tube 121 and the helical tip 9 on the end of the device. The rotation may continue until the thumbscrew 120 hits a stop on the sliding grip 117 or until the surgeon decides enough rotation has occurred. The thumbscrew is threaded and engaged with internal threads of the sliding grip, in the same fashion shown in
Distal to the sliding grip 117 on the handle is the steering knob 124. The steering knob 124 pivots about an axis in the handle. Inside the handle is a pass through rotating element such as those shown in
The integrated system works in a similar manner to the independent systems previously described. The doctor inserts the device into the femoral artery through a hemostatic sheath. The device is routed up the arterial system and over the aortic arch in a retrograde direction. When the tip of the device nears the aortic valve, the steering handle is actuated and the distal tip of the device is curved into a tight 180-degree shape. The curved tip is advanced into the ventricle and the catheter may be straightened. The doctor then steers the tip of the device toward the area to be treated and advances the inner catheter until the helical tip touches the tissue. The thumbscrew is then turned and the helical tip is anchored into the tissue. The doctor may then infuse therapeutic agent through the helical tip or imaging agent through the outer catheter to see the position and structure of the heart. Once the intervention is complete, the doctor can move to another position or remove the device from the body.
An alternate embodiment for an integrated system is shown in
The steerable guide shown in
The handle includes a distally extending tube 144 which extends distally over the drug delivery catheter tube. The distally extending tube fits within the bore 130. The distally extending tube 144 may have a groove 145 along its length to accept an alignment pin 131 on the inside of the steerable guide catheter handle. The interaction of the pin and groove can prevent rotation of the two devices relative to each other, facilitating rotating of the thumbscrew 146. The length of the distally extending tube 144 of the delivery catheter interacts with the length of the mating cavity in the steerable guide handle to control and limit the length that the delivery catheter distal tip can extend from the distal tip of the steerable guide tube. The distally extending tube 144 of the delivery catheter fits over the main delivery catheter tube 16 with clearance so the delivery catheter shaft can spin when the doctor turns the thumbscrew.
Thus, several embodiments of catheter systems which facilitate the delivery of drugs and therapeutic agents into the heart and other organs of the body have been describe. While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
1. A system for delivering a drug to a target site within a patient's body comprising:
- a steerable guide catheter comprising: a guide catheter having a distal end, a proximal end and a longitudinal axis; a housing engaging the proximal end of the guide catheter; a hemostatic adapter extending from the housing in communication with the proximal end of the guide catheter; and steering means for steering the guide catheter, the steering means providing rotation and deflection of the guide catheter, the deflection of the distal end greater than ninety degrees from the longitudinal axis; and
- a drug delivery catheter operable to dock on the guide catheter through the hemostatic adapter, the delivery catheter comprising: a handle having a longitudinal axis, a distal end, and a proximal end; a single lumen delivery catheter protruding out of the distal end of the handle and aligned substantially along the longitudinal axis of the handle and extensible beyond the distal end of the guide catheter; a helical drug delivery needle operably connected to the distal end of the delivery catheter; and means for repeatably and simultaneously rotating and advancing the drug delivery catheter within the guide catheter relative to the guide catheter.
2. The system of claim 1 further comprising:
- means for managing fluids to be passed through the drug delivery catheter, the fluid management means operably and rigidly secured to the drug delivery catheter to rotate and advance with the drug delivery catheter.
3. The system of claim 1 wherein the drug delivery catheter further comprises:
- a single lumen delivery catheter protruding out of the distal end of the handle and aligned substantially along the longitudinal axis of the handle and extensible up to six centimeters beyond the distal end of the guide catheter.
4. The system of claim 1 wherein the drug delivery catheter further comprises:
- a dual lumen delivery catheter having a first and second lumen, said delivery catheter protruding out of the distal end of the handle and aligned substantially along the longitudinal axis of the handle and extensible up to six centimeters beyond the distal end of the guide tube.
Filed: Aug 28, 2008
Publication Date: Dec 25, 2008
Inventors: Daniel C. Rosenman (South San Francisco, CA), Peter A. Altman (South San Francisco, CA), Brian K. Hakim (South San Francisco, CA), Daniel J. Kayser (South San Francisco, CA), Robert E. Maston (South San Francisco, CA), Douglas McEtchin (South San Francisco, CA)
Application Number: 12/200,812
International Classification: A61M 25/01 (20060101);