Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-05-05
2003-05-20
Walberg, Teresa (Department: 3742)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C606S198000
Reexamination Certificate
active
06565528
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to an drug-delivery tool and method of delivering selected therapeutic and/or diagnostic agents to target sites in selected body tissues. More particularly, the invention provides for the creation of temporary cavities in desired layers of a selected tissue, for example, myocardial tissue of the heart, and for the delivery of one or more selected agents therein.
BACKGROUND OF THE INVENTION
Intra-muscular needle injection of therapeutic compounds is well known in the medical arts, as is intra-coronary injection where pre-existing intra-coronary arteries provide perfusate conduits. In heart disease, the existing coronary artery in-flows to capillary beds is often compromised. Newly developed gene and protein therapeutic agents hold promise in their ability to act on the surviving smaller capillary beds to grow and expand them. As has been witnessed, the intra-myocardial cellular lattice limits angiogenic response to about 5-10 mm and similar limits occur with direct needle injections in stunned or ischemic heart tissue. The physician must work within an environment of compromised capillary bed vascularity. Physicians are further limited to some degree by drug viscosity—where the drug viscosity is too low, rapid wash-out can occur; and where too high, capillary occlusion can occur—as well as by high infusate pressure induced cellular damages. These problems are not typical of common healthy muscle tissue injections in the arm or leg. The prior art teaches the creation of permanent channels with the use of lasers, radio frequency heating and mechanical cutting means. Such channels often compromise the capillaries that are sought to be accessed with a drug, wash out readily, and resolve ultimately as fibrous connective scar tissue. Needle and membrane tools may improve access to capillaries but offer no stretching forces and don't offer unobstructed capillary access.
SUMMARY OF THE INVENTION
One embodiment of the invention provides a drug-delivery tool for delivering a drug to an internal member of a tissue, such as a heart-wall. The tool comprises an accessing device having distal and proximal ends, an inner lumen extending therebetween, a drug-delivery reservoir adapted to hold such drug, and a user-control structure at the accessing device's proximal end. The tool further includes a tissue-penetrating implement carried at the accessing device's distal end for axial movement into and out of the lumen. The implement has first and second expandable members which are disposed in a substantially co-extension condition, when the implement is disposed in a retracted condition within the lumen. Alternatively, the implement may assume an expanded, spaced-apart condition when the implement is advanced to an extended condition out of the lumen. At least one of the members has a tip for penetrating such tissue. A first operative connection exists between the control structure and the implement that is operable, upon user activation of the control structure, to advance the implement from its retracted to its extended condition. When the accessing device's distal end is placed against a surface region of the tissue, the implement is advanced into the tissue, causing the two expandable members to expand to form a cavity within the tissue. A second operative connection exists between the control structure and the reservoir that is operable, upon user activation of the control structure, to deliver drug from the reservoir into such cavity. Placement of the accessing device's distal end against a surface region of such tissue, and activation of the control structure results in the delivery of drug into a cavity within the tissue.
In another embodiment, the implement includes at least two expandable elements which move away from one another as the implement is being advanced, from its retracted to its extended condition, into such tissue, to form a cavity in the tissue.
In yet another embodiment, the second expandable member of the tissue-penetrating implement defines a lumen having a plurality of openings that permit direct communication of an drug passed into a cavity formed by the tool with at least about 90% of the surface area of the tissue directly bordering the drug receiving space.
In a particularly preferred embodiment, the accessing device is a flexible catheter accessing device; and further comprises a pull-wire assembly extending longitudinally through the catheter accessing device, the pull-wire assembly being is operable to deflect the distal end of the accessing device substantially within a plane; and one or more force contact transducers mounted at the distal end of the accessing device within the deflection plane. This embodiment may further comprise one or more additional force contact transducers mounted at the distal end of the accessing device outside of the deflection plane.
In another embodiment, the first expandable member further comprises construction from a shape memory material capable of a first remembered curved shape, and a second, stress induced linear shape causing the first expandable member to cut in an arc shape as it is advanced through a tissue upon extension from the confines of the accessing device lumen.
In still another embodiment, the second expandable member comprises a ribbed balloon, wherein each rib defines a lumen in fluid communication with the drug-delivery reservoir, and each rib further defines a plurality of exit ports from the rib lumen that the drug may perfuse through into the formed cavity.
In another embodiment, the first expandable member is formed in a cork-screw shape tubular member defining a lumen within exiting at an end distal to the accessing device and in communication with the drug-delivery reservoir, the first expandable member is rotatable along its axis to permit it to screw into a tissue upon axial rotation, and upon stopping axial rotation, withdraw into the lumen of the accessing device thereby pulling the tissue up into the lumen of the accessing device until such tissue is sealably urged against the accessing implement's lumen edge causing a seal to form between the accessing implement's lumen edge and the tissue, and further causing a cavity to form between the distal region of the first expandable member and the tissue adjacent to that region.
In one embodiment, some of the expandable members of the tissue-penetrating implement define lumens with a plurality of openings in fluid communication with the drug-delivery reservoir such that a drug may be introduced into a formed cavity with at least about 90%, and preferably greater than about 95%, of the surface area of the tissue directly bordering the cavity.
The accessing device can be, for example, a flexible catheter accessing device or the accessing device of an endoscope-type tool. In an embodiment of the former (i.e., a catheter-type tool), the tool further includes (i) a pull-wire assembly extending longitudinally through the catheter accessing device, with the pull-wire assembly being operable to deflect a distal-end region of the accessing is device substantially within a plane; and (ii) one or more (for example, two) ultrasound or force contact transducers mounted on opposing sides of the orifice at the distal end of the accessing device within the deflection plane. Optionally, one or more (for example, two) additional transducers can be mounted at the distal end of the accessing device outside of the deflection plane.
One aspect of the present invention provides an drug-delivery tool for delivering a selected diagnostic or therapeutic agent to a target site within a selected body tissue, such as myocardial tissue of the heart. Generally, the drug-delivery tool includes an accessing device having proximal and distal ends, with a lumen extending between such ends and terminating at an orifice at the distal end. A tissue-penetrating implement is movable between a retracted condition, within a distal region of the lumen, and an extended condition, extending out of the orific
Fastovsky L
Pennie & Edmonds LLP
Scimed Life Systems Inc.
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