Surgery – Means for introducing or removing material from body for... – Infrared – visible light – ultraviolet – x-ray or electrical...
Reexamination Certificate
1999-11-29
2001-07-17
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Infrared, visible light, ultraviolet, x-ray or electrical...
Reexamination Certificate
active
06263236
ABSTRACT:
BACKGROUND OF THE INVENTION
The technical field of this invention is catheter-based methods and devices for treatment of cardiovascular conditions.
Diseased sites in blood vessels, such as atherosclerotic plaques, aneurysms, stenotic lesions, blocked arteries, and the like, have often been treated using catheters that deliver light, heat or therapeutic agents to the treatment site. Catheters used for this purpose are designed to fit suitably into the lumen of the vessel under treatment.
In U.S. Pat. No. 5,053,033 issued to Clarke, UV radiation is delivered by means of an optical fiber incorporated in a catheter to reduce incidences of restenosis at an angioplasty site. The blood vessel walls are irradiated with UV light during the course of angioplasty procedure, and the effect of the irradiation is to reduce proliferation of smooth muscle cells at this site.
In U.S. Pat. No. Reissue 34,544 issued to Spears et al., therapies are disclosed based on the administration of haematoporphyrin, which is selectively taken up by atherosclerotic plaques. Subsequently, light in the IR range is delivered to the plaque, resulting in the lysis of the plaque. A balloon catheter equipped with a flexible optical fiber is used to deliver the light. When the balloon is inflated, it displaces the opaque blood, allowing transmission of the IR energy through the balloon to the plaque.
In U.S. Pat. No. 5,620,438 issued to Amplatz et al., a balloon catheter is disclosed that causes the radiant energy to exit the catheter in a radial band to treat blood vessel walls. The area of the vessel wall is exposed to the radiant energy in a controlled manner following balloon angioplasty to reduce the tendency of restenosis.
In U.S. Pat. No. 5,797,868 issued to Leone, a photodynamic balloon catheter is used to evenly distribute radiation to the vessel wall. The catheter has a light passing inner tube, a light passing fluid and a light passing inflatable balloon. Light emanating from an optical fiber is reflected through these components to provide uniform illumination within the blood vessels.
Medicaments can also be administered to a subject using catheters. The advantage of using a catheter is that the catheter provides a direct delivery of the medicament to the target site. This minimizes the chance of side effects often encountered by systemic administration of the medicament. In U.S. Pat. No. 5,087,244, issued to Wolinsky et al., a catheter with a flexible balloon having a plurality of minute openings is used to deliver drugs to the vessel. For example, the balloon can be inflated with a heparin solution, and as the walls of the balloon contact the arterial wall, the heparin exits the balloon, directly onto the walls.
However, a serious drawback to using catheters for these types of treatments is that the catheter blocks the flow of blood through the vessel distal to the delivery site, depriving tissue of needed blood. This can cause tissue damage, even when the procedure is performed expediently. Therefore, the amount of time available for drug or light delivery is limited.
The object of this invention is to provide a catheter that can deliver light, heat or a therapeutic agent to a target region in a vessel wall without occluding blood flow in the vessel.
SUMMARY OF THE INVENTION
In general, methods and devices are disclosed for delivering energy and/or therapeutic agents to a target region in a vessel without occluding fluid flow in the vessel.
In one aspect, the invention features a catheter for applying energy to a wall of a vessel without occluding fluid flow. The catheter is typically an elongated hollow instrument having at least one lumen. A waveguide can be disposable within the lumen with the proximal end of such waveguide being adapted to receive energy from an energy source, and a diffuser or distributor disposed of at the distal end of the waveguide constructed to receive energy transmitted from the energy source via the waveguide, and to deliver the energy into a target region of a vessel wall. The invention can further include an expansion mechanism connected to the energy distributor for expanding the instrument at the target region in order to bring the energy distributor into close proximity with the vessel wall while creating at least one fluid passageway through the expanded portion of the instrument.
In one embodiment, the waveguide is a single optical fiber. In another embodiment, the waveguide is a plurality of optical fibers. In a preferred embodiment, the energy distributor is a light distributor. In one embodiment, the light distributor has a single light diffusive tube. In another embodiment, the light diffuser has a plurality of light diffusive tubes. In yet another embodiment, the light diffuser further comprises a light scattering material which directs light to the walls of the light distributor. The light scattering material can further comprise a polymeric material which has light scattering particles dispersed therein. Examples of light scattering particles include, but are not limited to, the group consisting of alumina, silica, and titania compounds and mixtures thereof In another embodiment, the light scattering material is coated on the inner side of the light diffuser. The instrument can further comprises a sheath-like casing that encapsulates the energy-distributing elements.
In another embodiment of the invention, the energy waveguide can be replaced by a medicament conduit which similarly cooperates with an expansion mechanism to provide target administration of a drug or other therapeutic agent to a region of a vessel wall without occluding blood flow. In yet another embodiment, the energy waveguide and medicament conduit can be used in tandem. In another aspect of the invention, various expansion mechanisms are disclosed which bring a portion of the instrument into close proximity with the vessel wall. In one embodiment, the expansion mechanism comprises a flexible spring expander. In another embodiment, the expansion mechanism comprises a coil expander. In yet another embodiment, the expansion mechanism includes a shape-memory material that expands as it is pushed out of a lumen in the instrument. The expansion mechanism may also include a pull wire or push wire or other control mechanism to activate the expansion mechanism from a contracted state to an expanded state.
In another aspect, the invention features a method for delivering energy or medicaments to the walls of a vessel without occluding fluid flow by inserting a catheter having an expansion mechanism into the lumen of the vessel. The catheter having an elongated hollow instrument with at least one lumen, an optional waveguide disposable within the lumen with a proximal end adapted to receive energy, a distributor at the distal end of the waveguide constructed to receive and distribute the energy or medicament to the target region of a vessel wall, and an expansion mechanism for expanding the distal end of the instrument at the target region. The expansion mechanism is activated, thereby expanding the distributor at the target region while creating at least one fluid passageway for blood flow through the diffuser. For photo or thermal therapies, energy can be delivered from an energy source to the interior of the energy distributor via the waveguide and transmitted from the distributor to the target region.
Alternatively, in another aspect, the invention features a method for treating a lesion in a vessel without occluding fluid flow by inserting a catheter into the lumen of a vessel. In this method the catheter is an elongated hollow instrument with at least one lumen, and optionally includes a waveguide disposable within the lumen with a proximal end adapted to receive energy together with an energy distributor at the distal end of the waveguide constructed to receive and distribute the energy to the target region of a vessel wall. Alternatively, the lumen is used to transport a drug or therapeutic agent to a drug dispenser. An expansion mechanism connected to the energy or drug distributor for exp
Kasinkas Michael
Ziebol Robert
Engellenner Thomas J.
Illumenex Corporation
Mendez Manuel
Nutter & McClennen & Fish LLP
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