« AnteriorContinuar »
SUBSTANCE DELIVERY APPARATUS AND A
METHOD OF DELIVERING A
THERAPEUTIC SUBSTANCE TO AN
This is a continuation-in-part of U.S. patent application Ser. No. 09/352,628 filed on Jul. 13,1999, now U.S. Pat. No. 6,283,947.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains generally to a medical device useful for delivering a substance to a biological 15 passageway. More specifically, the present invention pertains to a catheter device having a syringe assembly useful for delivering a therapeutic substance to a passageway, such as a blood vessel.
2. Description of the Related Art 20 Percutaneous transluminal coronary angioplasty (PTCA)
is a procedure for treating heart disease. A catheter assembly having a balloon portion is introduced percutaneously into the cardiovascular system of a patient via the brachial or ^ femoral artery. The catheter assembly is advanced through the coronary vasculature until the balloon portion is positioned across the occlusive lesion. Once in position across the lesion, the balloon is inflated to a predetermined size to radially compress the atherosclerotic plaque of the lesion 3Q against the inner wall of the artery to dilate the lumen. The balloon is then deflated to a smaller profile to allow the catheter to be withdrawn from the patient's vasculature.
Restenosis of the artery commonly develops over several months after the procedure, which may require another 35 angioplasty procedure or a surgical by-pass operation. Restenosis is thought to involve the body's natural healing process. Angioplasty or other vascular procedures injure the vessel walls, removing the vascular endothelium, disturbing the tunica intima, and causing the death of medial smooth 40 muscle cells. Excessive neoinitimal tissue formation, characterized by smooth muscle cell migration and proliferation to the intima, follows the injury. Proliferation and migration of smooth muscle cells (SMC) from the media layer to the intima cause an excessive production of extra cellular matri- 45 ces (ECM), which is believed to be one of the leading contributors to the development of restenosis. The extensive thickening of the tissues narrows the lumen of the blood vessel, constricting or blocking blood flow through the vessel. 50
To reduce the chance of the development of restenosis, therapeutic substances are administered to the treatment site. For example, anticoagulant and antiplatelet agents are commonly used to inhibit the development of restenosis. In order to provide an efficacious concentration to the target site, 55 systemic administration of such medication often produces adverse or toxic side effects for the patient. Local delivery is a preferred method of treatment in that smaller total levels of medication are administered in comparison to systemic dosages, but are concentrated at a specific site. Local go delivery, thus, produces fewer side effects and achieves more effective results.
One commonly applied technique for the local delivery of a therapeutic substance is through the use of a medicated, implantable prosthesis, one example of which includes a 65 stent. A stent coated with a polymeric carrier, which is impregnated with a therapeutic substance, can be deployed
at a selected site of treatment. The polymeric carrier allows for a sustained delivery of the therapeutic substance. A disadvantage associated with the use of medicated stents is that the quantity of the substance that can be impregnated in the polymeric carrier is limited. In order to increase the capacity of the polymeric carrier, the amount of polymeric material employed, and in effect the thickness of the coating, must be increased to accommodate the quantity of the substance used. An increase in the profile of the coating significantly limits the applications for which the stents can be used.
Another disadvantage associated with the use of medicated stents is that the polymeric carrier is only capable of applying the therapeutic substance to the inner surface of the tunica intima layer of the vessel. The polymeric carrier is incapable of significantly introducing a therapeutic substance to the tunica adventitia or the tunica media layers of the vessel. Accordingly, it is desirable to provide a substance delivery apparatus which is capable of applying any desired amount of therapeutic substances to the tunica adventitia and media layers to inhibit migration of SMC and the development of ECM.
Another commonly applied technique for the local delivery of a therapeutic substance is through the use of porous balloons attached to a distal end of a catheter assembly. The expansion of the balloon, which in effect results in the dilation of the occluded region, is accomplished by injecting a therapeutic substance into the balloon. The use of a therapeutic substance as an expansion fluid additionally functions as a medicament for the diseased region, as the therapeutic substance is discharged from the porous balloon during and subsequent to the expansion therapy. A shortcoming associated with this procedure is that the therapeutic substance is contiguously carried off in the patient's blood stream as it is being discharged from the balloon, which results in an ineffective treatment of the target site and adverse exposure of the substance to healthy tissues. Accordingly, it is desirable to provide a substance delivery apparatus that is capable of applying a therapeutic substance to the diseased region without significant loss of the substance caused by the downstream flow of blood.
SUMMARY OF THE INVENTION
A catheter assembly is provided having a balloon disposed at the distal end thereof. The balloon is capable of being inflated to selectively dilate from a collapsed configuration to an expanded configuration. The balloon is also capable of being deflated after inflation to return to the collapsed configuration or a deflated profile. A syringe assembly is in fluid communication with a delivery lumen of the catheter assembly for allowing a therapeutic substance to be injected into a tissue of a lumen. The syringe assembly includes a portion capable of pivoting from a first position towards a second position when the balloon is being inflated from the collapsed configuration to the expanded configuration. The portion of the syringe assembly is capable of pivoting from the second position back towards the first position when the balloon is being deflated.
In accordance with one embodiment, the balloon is made from a porous membrane. A therapeutic substance can be used as an inflation fluid for the porous balloon. The pores allow the therapeutic substances to be discharged out from the balloon for the local treatment of the tissues. The therapeutic substance supplied into and discharged out from the balloon can be the same as or different from the therapeutic substance administered by the syringe assembly.
In another embodiment, the delivery apparatus can include any suitable number of pivotally activated syringe assemblies. Each of the syringe assemblies can communicate with a common delivery lumen of the catheter assembly so that each of the syringe assemblies is capable of injecting 5 the same therapeutic substance or the same combination of therapeutic substances. Alternatively, each of the syringe assemblies can be linked to an independently operated delivery lumen, allowing each of the syringe assemblies to be capable of delivering a different substance or a different 10 combination of substances.
A method is provided for administering a therapeutic substance using the embodiments of the above described catheter assembly. The catheter assembly is inserted in a biological passageway of a subject and the syringe assembly 15 is positioned at a desired area of treatment. The syringe assembly is pivotally rotated to cause a needle of the syringe assembly to penetrate into a wall of the desired area of treatment. A therapeutic substance is supplied through the delivery lumen of the catheter assembly to administer the 20 therapeutic substance to the desired area of treatment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cross-sectional view of one embodiment of a substance delivery apparatus of the present invention in 25 the form of a catheter assembly having a balloon in a collapsed configuration and a syringe assembly is a rested position;
FIG. 2 is a partial cross-sectional view of the delivery apparatus of FIG. 1, illustrating the balloon in an expanded configuration and the syringe assembly pivotally rotated to a delivery position;
FIG. 3 is a partial cross-sectional view of another embodiment of a substance delivery apparatus of the present 3J invention in the form of a catheter assembly having a balloon in an expanded configuration and a syringe assembly pivotally rotated toga delivery position;
FIG. 4(a) is a partial cross-sectional view of another embodiment of a substance delivery apparatus of the present 40 invention in the form of a catheter assembly having a balloon in an expanded configuration and a syringe assembly pivotally rotated to a delivery position, the delivery apparatus includes an iontophoreses element for providing a transport force for the substance; 45
FIG. 4(b) is a partial cross-sectional view of another embodiment of a substance delivery apparatus of the present invention in the form of a catheter assembly having a balloon in an expanded configuration and a syringe assembly pivotally rotated to a delivery position, the delivery 50 apparatus includes an ultrasonic transducer;
FIGS. 5 and 6 are illustrations of acts performed for delivering a therapeutic substance to the tissues of a blood vessel using one embodiment of the substance delivery apparatus of the present invention; 55
FIG. 7 is a cross-sectional view of a mammalian artery, illustrating each layer of the wall; and
FIG. 8 is a partial prospective view of a mammalian vessel, illustrating the vasa vasorum networked along the tunica adventitia layer of the vessel. 60
DETAILED DESCRIPTION OF THE
Referring now to the drawings, wherein similar parts are identified by like reference numerals, FIGS. 1 and 2 illus
trate a substance delivery apparatus in accordance with one embodiment of the invention. In general, the substance delivery apparatus provides a system for delivering a substance, such as a therapeutic substance or a combination of therapeutic substances, to or through a desired area of a passageway in order to treat a localized area of the passageway or to treat a localized area of tissue located adjacent to the passageway. The substance delivery apparatus includes a catheter assembly 10, which is intended to broadly include any medical device designed for insertion into a body passageway to permit injection and/or withdrawal of fluids, to maintain the patency of the passageway, or for any other purpose. It is contemplated that the substance delivery apparatus has applicability for use with any biological passageway, including blood vessels, urinary tract, intestinal tract, kidney ducts, wind pipes, and the like.
Catheter assembly 10 is defined by an elongated catheter tube 12 having a proximal end (not illustrated) and a distal end 14. Catheter assembly 10 can include a guidewire lumen 16 for allowing catheter assembly 10 to be fed and maneuvered over a guidewire 18. A balloon 20 is incorporated at distal end 14 of catheter assembly 10 and is in fluid communication with an inflation lumen 22 of catheter assembly 10.
Balloon 20 has a pair of opposing ends 24 and 26 engaged to catheter tube 12 to define a balloon chamber 28. Balloon 20 is formed from a balloon wall or membrane 30 which is selectively inflatable to dilate from a collapsed configuration to a desired and controlled expanded configuration. Balloon 20 can be selectively inflated by supplying a fluid into inflation lumen 22 at a predetermined rate of pressure, for example 1-20 atm. Balloon wall 30 is selectively deflatable, after inflation, to return to the collapsed configuration or a deflated profile. Balloon wall 30 can be defined by three sections, a distal wall 32, a medial wall 34, and a proximal wall 36. In one embodiment, as illustrated in FIG. 2, proximal wall 36 of balloon 20 is generally perpendicular to a longitudinal axis x of balloon 20, i.e., <I> is equal to about 90°, when balloon 20 is in the expanded configuration. In an alternative embodiment, as illustrated in FIG. 3, proximal wall 36 can taper from opposing end 26 at any suitable angle <P, typically between about 45° to less than about 90°, when balloon 20 is in the expanded configuration.
The three wall sections 32, 34, and 36 can be bound together by seams or be made out of a single seamless material. Balloon 20 can be made from any suitable material, including, but not limited to, polymers and copolymers of polyolefins, polyamides, polyesters and the like. The specific material employed must be mutually compatible with the fluids employed in conjunction with balloon 20 and must be able to stand the pressures that are developed within balloon chamber 28. Balloon wall 30 can have any suitable thickness so long as the thickness does not compromise properties that are critical for achieving optimum performance. The properties include high burst strength, low compliance, good flexibility, high resistance to fatigue, the ability to fold, the ability to cross and recross a desired region of treatment or an occluded region in a lumen, and low susceptibility to defect caused by handling. By way of example, and not limitation, the thickness can be in the range of about 10 microns to about 30 microns, the diameter of balloon 20 in the expanded configuration can be in the range of about 2 mm to about 10 mm, and the length can be in the range of about 3 mm to about 40 mm, the specific specifications depending on the procedure for which balloon 20 is to be used and the anatomy and size of the target lumen in which balloon 20 is to be inserted.