Balloon catheter devices with drug delivery extensions

A medical device is provided for dilatation of a vessel and delivery of a therapeutic agent to a wall of the vessel. The medical device comprises a catheter, a balloon located at a distal end of the catheter, and a drug delivery extension. The drug delivery extension is configured to extend beyond an outer surface of the balloon when the balloon is in an expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon. The drug delivery extension may be one or more tubes, elongate members and/or expandable structures. The drug delivery extension may include a sheath for drug delivery.

TECHNICAL FIELD

The present invention relates to medical devices, more particularly, to catheter devices.

BACKGROUND

Catheters are used in a wide variety of minimally-invasive or percutaneous medical procedures. Balloon catheters having drug coatings may be used to treat diseased portions of blood vessels. Typically, the balloon is inserted through a peripheral blood vessel and then guided via a catheter through the vascular system to the target intravascular site.

In many proposed drug delivery balloons, the balloon is similar to balloons that have been used in angioplasty procedures to dilate a stenosed region of a blood vessel. Such balloons have commonly been generally non-compliant balloons that can be inflated to relatively high inflation pressures without rupturing the blood vessel. In many proposed drug delivery balloons, the balloon is coated with or otherwise provided with drug on its outer surface. When the balloon is expanded at the area of the stenosis, the balloon not only opens the constriction as in a conventional angioplasty procedure but it also delivers drug to the area that is dilated by the balloon.

Despite the developments both with respect to balloon dilatation and drug delivery, there is a need for improvements in treatment devices and methods.

SUMMARY

In accordance with certain embodiments of the disclosure, a treatment device is provided in which the area of drug delivery extends beyond the area of balloon dilatation.

For example, in certain instances, it will be desirable that the area of drug delivery be different from the area of balloon dilatation. In certain instances, it may be desired that drug be delivered to one or more areas adjacent the area of balloon dilatation. It may be desired that this drug delivery to one or more areas adjacent the area of balloon dilatation be in combination with drug delivery to all or part of the area of balloon dilatation.

In one embodiment of the disclosure, a medical device is provided for dilatation of a vessel and delivery of therapeutic agent to a wall of the vessel. The medical device comprises a catheter, a balloon located at a distal end of the catheter, the balloon having a collapsed configuration and an expanded configuration, the balloon having an outer surface configured to press against the wall of the vessel when the balloon is expanded to its expanded configuration for dilatation of a constriction in the vessel, and a drug delivery extension. The drug delivery extension is configured to extend beyond the outer surface of the balloon when the balloon is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon. When the drug delivery extension is deployed, the drug delivery extension may extend, for example, distally from a distal end of the balloon in a direction generally parallel to a longitudinal axis of the balloon, proximally from a proximal end of the balloon in a direction generally parallel to a longitudinal axis of the balloon, or both distally and proximally. Additionally or alternatively, when the drug delivery extension is deployed, the drug delivery extension may extend away from the outer surface of the balloon in a direction extending away from the longitudinal axis of the balloon, for example for treatment of a side branch.

The drug delivery extension may comprise a tube having a rolled configuration and an unrolled configuration, wherein when the tube is in its unrolled configuration, the tube extends beyond the outer surface of the balloon in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon. The medical device may further comprise a compression reservoir, wherein when the balloon is expanded to its expanded configuration and the compression reservoir is pressed by the balloon against the wall of the vessel, the compression reservoir is compressed to a compressed condition. Compression of the compression reservoir to its compressed condition causes the tube to unroll from its rolled configuration to its unrolled configuration. The compression reservoir may be a portion of the tube or a separate component. A plurality of tubes may be provided, each having a rolled configuration and an unrolled configuration.

The drug delivery extension may comprise an elongate member having a collapsed configuration and an expanded configuration, wherein when the elongate member is in its expanded configuration, the elongate member extends beyond the outer surface of the balloon in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon. The medical device may further comprise an actuation mechanism for deploying the elongate member from its collapsed configuration to its expanded configuration. The actuation member may comprise a ring and/or one or more deployment wires. A plurality of elongate members may be provided, each having a collapsed configuration and an expanded configuration.

The drug delivery extension may comprise an expandable structure having a collapsed configuration and an expanded configuration, wherein when the expandable structure is in its expanded configuration, the expandable structure extends beyond the outer surface of the balloon in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon. The medical device may further comprise a compression reservoir, wherein when the balloon is expanded to its expanded configuration and the compression reservoir is pressed by the balloon against the wall of the vessel, the compression reservoir is compressed to a compressed condition. Compression of the compression reservoir to its compressed condition causes the expandable structure to expand from its collapsed configuration to its expanded configuration. The compression reservoir may be a portion of the expandable structure or a separate component. The expandable structure may comprise a plurality of tubes, and the compression reservoir may comprise a portion of the tubes located on the outer surface of the balloon.

The therapeutic agent may be located on the outside of the drug delivery extension. For example, the therapeutic agent may be located on the outside of one or more tubes, on the outside of one or more elongate members, and/or on the outside of an expandable structure. Additionally or alternatively, the therapeutic agent may be located inside the drug delivery extension and may be forced out of openings in the drug delivery extension when the drug delivery extension is deployed. Additionally or alternatively, the medical device may further comprise a drug delivery sheath located on the outside of the drug delivery extension, wherein the therapeutic agent is located on the sheath, and wherein when the drug delivery extension is deployed, the drug is delivered from the sheath to the vessel wall.

As mentioned above, when the drug delivery extension is deployed, the drug delivery extension may extend distally from a distal end of the balloon, proximally from a proximal end of the balloon, or both distally and proximally. Also, as mentioned above, when the drug delivery extension is deployed, the drug delivery extension may extend generally radially outwardly from the outer surface of the balloon, for example for treatment of a side branch.

In another embodiment of the disclosure, a method for dilatation of a vessel and delivery of therapeutic agent to a wall of the vessel is provided, the method comprising: providing a medical device comprising: a catheter; a balloon located at a distal end of the catheter, the balloon having a collapsed configuration and an expanded configuration, the balloon having an outer surface configured to press against the wall of the vessel when the balloon is expanded to its expanded configuration for dilatation of a constriction in the vessel; and a drug delivery extension configured to extend beyond the outer surface of the balloon when the balloon is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface of the balloon; delivering the balloon to the constriction in the vessel; expanding the balloon from its collapsed configuration to its expanded configuration such that the outer surface of the balloon presses against the wall of the vessel for dilatation of the constriction; and deploying the drug delivery extension to deliver the therapeutic agent to an area beyond the outer surface of the balloon. The medical device in the method may have one or more of the features described herein. The step of expanding the balloon from its collapsed configuration to its expanded configuration such that the outer surface of the balloon presses against the wall of the vessel may cause the deployment of the drug delivery extension.

DETAILED DESCRIPTION

FIG. 1shows a medical device10according to one embodiment of the disclosure. The medical device10comprises a catheter14with a balloon20located at a distal end16of the catheter14.

The catheter14and balloon20may be constructed and operated similarly to balloon catheters as known in the art, including but not limited to angioplasty catheters, stent delivery catheters, inflation catheters, and/or perfusion catheters. Any of various mechanisms conventionally used for the delivery, actuation, or expansion (e.g., by inflation) of balloon catheter devices may be used in conjunction with the catheter14and balloon20. A lumen18may be provided through the balloon20, for example for delivery of the balloon catheter over a guidewire and/or for perfusion purposes. The catheter devices of the present disclosure may be used in conjunction with other treatment or drug delivery devices, such as stents, as are known in the art.

Similar to conventional balloon catheters such as those known in the art, the balloon20has a collapsed configuration and an expanded configuration.FIG. 1shows the balloon20in its collapsed configuration, whileFIG. 3shows the balloon20in its expanded configuration.

The balloon20has an outer surface22configured to press against the wall of a vessel when the balloon20is expanded to its expanded configuration. In this way, expansion of the balloon20can cause a dilatation of a constriction in the vessel, as in angioplasty procedures.

The medical device10has a drug delivery extension30. The drug delivery extension30is configured to extend beyond the outer surface22of the balloon20when the balloon20is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface22of the balloon20. For example, as seen inFIG. 3, when the drug delivery extension30is deployed, the drug delivery extension30may extend distally from a distal end26of the balloon20and/or proximally from a proximal end24of the balloon20.

In the embodiment illustrated inFIGS. 1-3, the drug delivery extension30comprises a plurality of tubes32. Each tube32has an undeployed, rolled configuration, as shown inFIG. 1, and a deployed, unrolled configuration, as shown inFIG. 3. As can be seen inFIG. 3, when a tube32is in its unrolled configuration, the tube32extends beyond the outer surface22of the balloon20, and, in this way, the tube32delivers therapeutic agent to an area beyond the outer surface22of the balloon20. In the example illustrated inFIG. 3, when the drug delivery extension30is deployed, the drug delivery extension30extends in a generally longitudinal direction both distally from a distal end26of the balloon20and proximally from a proximal end24of the balloon20.

In one example of an embodiment according toFIGS. 1-3, the tubes32may be filled with fluid and may be coated with, or may otherwise carry, a therapeutic agent. For example, the therapeutic agent may be coated on the tubes32in a polymer matrix. The fluid on the inside of the tubes32in this example is for purposes of deploying the tubes32. In this example, the portion of each tube32extending along the outer surface22of the balloon20serves as a compression reservoir34. When the balloon20is expanded, the pressure of the balloon20presses each compression reservoir34against the wall of the vessel, thereby compressing the compression reservoirs34. This in turn forces fluid from the compression reservoirs34into the areas of the rolled sections36. When this happens, the rolled sections36unroll to become unrolled sections38as shown inFIG. 3. Thus, when the balloon20is expanded to its expanded configuration and each compression reservoir34is pressed by the balloon20against the wall of the vessel, the compression reservoir34is compressed to a compressed condition. Compression of the compression reservoir34to its compressed condition causes the tube32to unroll from its rolled configuration to its unrolled configuration.

As shown inFIGS. 1-3, the drug delivery extension30may comprise a plurality of tubes32, each having a rolled configuration and an unrolled configuration. As can be seen in the cross-sectional view ofFIG. 2, eight tubes32are shown in this example, but more or fewer tubes32may be used. The tubes32may be any suitable size or shape and need not be circular in cross-section. For example, the cross-sectional shape of the tubes32may be oval, rectangular, square, or another suitable shape.

In the example shown inFIGS. 1-3, the portion of each tube32extending along the outer surface22of the balloon20extends in a longitudinal direction generally parallel to the longitudinal axis of the balloon20. Other suitable configurations are possible. For example, the portion of each tube32extending along the outer surface22of the balloon20may extend in a generally helical direction around the outer surface22of the balloon20. In this way, the length of this portion is increased. Since this portion becomes compressed upon balloon expansion and serves as the compression reservoir34, it will be appreciated that having this portion be longer will result in more fluid being displaced, thereby increasing the ability to extend the drug delivery extension30beyond the outer surface22of the balloon20.

In the example ofFIGS. 1-3, the compression reservoir34is a portion of the tube32itself. Alternatively, a separate component, such as a compressible bladder or other structure, may be provided as the compression reservoir. Thus, for example, the compression reservoir may be provided on the outer surface22of the balloon20, and the tubes may extend distally and/or proximally from the compression reservoir. In one example, the compression reservoir is a cylindrical sleeve around the outer surface22of the balloon20, with tubes serving as the drug delivery extension and extending distally and proximally from the cylindrical sleeve. Additionally or alternatively, if desired, a non-compliant sheet or tube may be placed around the balloon20and the compression reservoir, whether the compression reservoir is a portion of a tube, a sleeve, or another suitable configuration. If the non-compliant sheet or tube is slightly smaller in diameter than the balloon20, upon expansion of the balloon20the compression reservoir will be squeezed between the balloon20and the non-compliant sheet or tube. In this manner, the drug delivery extension may be deployed without the need for compressing the compression reservoir by pressure against the vessel wall.

As mentioned herein, the therapeutic agent may be located on the outside of the tubes32. Additionally or alternatively, the therapeutic agent may be located inside the tubes32and may be forced out of openings in the tubes32when the tubes32are deployed. The therapeutic agent may form or be part of the fluid located in the tubes32for deployment of the tubes.

A medical device as described herein may be used in the following manner. First, the balloon, in its collapsed configuration, is delivered to the constriction in the vessel. Techniques such as those known in the art can be used to position the balloon at the desired site. Once the balloon is at the constriction, the balloon is expanded from its collapsed configuration to its expanded configuration. When sufficiently expanded, the outer surface of the balloon presses against the wall of the vessel for dilatation of the constriction. At or around this time, the drug delivery extension is deployed to deliver the therapeutic agent to an area beyond the outer surface of the balloon. In the example as described herein in which tubes32have compression reservoirs34that are compressed when the outer surface22of the balloon20presses the compression reservoirs34against the wall of the vessel, the step of expanding the balloon20to cause the outer surface22of the balloon20to press against the wall of the vessel also compresses the compression reservoirs34and causes the deployment of the drug delivery extension30. In certain embodiments, increasing the pressure in the balloon20can cause an increased extension of the tubes32, thereby allowing control of the length of the extension.

When the therapeutic agent is on the outside of the tubes32, the unrolling of the tubes32causes the therapeutic agent to contact the vessel wall and thereby be delivered to areas of the vessel wall distally and/or proximally of the balloon20. Similarly, when therapeutic agent is forced out of the interior of tubes32upon deployment of the tubes32, such action also can cause the therapeutic agent to be delivered to areas of the vessel wall distally and/or proximally of the balloon20.

Delivering therapeutic agent to an area beyond the outer surface of the balloon results in improved treatment for certain situations. For example, a blood vessel may have stenosis over a certain length, wherein a small section near the center of the length is heavily stenosed (e.g., greater than 70% stenosed) but the remainder of the length is not as heavily stenosed (e.g., less than 30% stenonsed). It may be desired to dilatate only the heavily stenosed area, in order to avoid injury or other negative effects that might be associated with more extensive dilatation, or because of difficulties in accessing other areas for dilatation. However, while it may be desired to dilatate only the heavily stenosed area, it may be desired to deliver drug not just to the heavily stenosed area but also to adjacent areas. It may be desired to deliver drug to adjacent areas because, for example, dilatation of the heavily stenosed area can lead to restenosis over a longer area. Drugs may be delivered to the dilatation area and an adjacent area to promote healing or to prevent restenosis over a longer area, or for other reasons known in the art for which drugs are delivered in the area of a balloon dilatation. It will be appreciated that a medical device such as that described herein with a drug delivery extension to deliver therapeutic agent to an area beyond the outer surface of the balloon can achieve this goal of dilation over a first area with drug delivery over a second area.

The drug may be delivered not only to an area beyond the outer surface of the balloon but also to all or part of the area of balloon dilatation. This may be accomplished in ways known in the art, e.g., by coating the balloon, or by ways described herein, e.g., by drug delivery from tubes extending along the outer surface of the balloon. In certain instances, it may be desired that the drug be delivered only to an area beyond the outer surface of the balloon, which can also be accomplished with a device as described herein. In cases in which a drug coated stent is placed using the balloon, the balloon itself may be needed to deliver drug only to areas beyond that at which the stent is being placed. This may be include areas along the balloon surface where the stent is not located as well as areas beyond the balloon surface.

As mentioned herein, in a medical device10like that shown inFIGS. 1-3, when the tubes32are deployed, the tubes32may extend distally from the distal end26of the outer surface22of the balloon20, proximally from a proximal end24of the outer surface22of the balloon20, or both distally and proximally. In the embodiment illustrated inFIGS. 1-3, the tubes32extend in a direction generally parallel to a longitudinal axis of the balloon20both distally from the distal end26of the outer surface22of the balloon20and proximally from a proximal end24of the outer surface22of the balloon20. Additionally or alternatively, when the drug delivery extension is deployed, the drug delivery extension may extend away from the outer surface22of the balloon20in a direction extending generally away from the longitudinal axis of the balloon20.

FIG. 4shows an example of such a medical device wherein the drug delivery extension extends away from the outer surface of the balloon in a direction extending generally away from the longitudinal axis of the balloon.FIG. 4shows a medical device11according to another embodiment of the disclosure. The medical device11, like that inFIGS. 1-3, comprises a catheter14with a balloon20located at a distal end16of the catheter, which may be similar to the catheter14and balloon20as described with respect toFIGS. 1-3.

InFIG. 4, the medical device11has a drug delivery extension31comprising a plurality of tubes33. The drug delivery extension31is configured to extend away from the outer surface22of the balloon20when the balloon20is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface22of the balloon20. For example, as seen inFIG. 4, when the drug delivery extension31is deployed, the drug delivery extension31extends away from the outer surface22of the balloon20in a direction extending generally away from the longitudinal axis of the balloon20.

In the embodiment illustrated inFIG. 4, similar to the embodiment ofFIGS. 1-3, the drug delivery extension31comprises a plurality of tubes33. Each tube33has an undeployed, rolled configuration (not shown, but similar to the rolled configuration as shown inFIG. 1), and a deployed, unrolled configuration, as shown inFIG. 4. As can be seen inFIG. 4, when a tube33is in its unrolled configuration, the tube33extends away from the outer surface22of the balloon20, and, in this way, the tube33delivers therapeutic agent to an area beyond the outer surface22of the balloon20.

Similar to the drug delivery extension described herein with reference toFIGS. 1-3, the tubes33may be filled with fluid and may be coated with, or may otherwise carry, a therapeutic agent. In this example, a portion of each tube33extending along the outer surface22of the balloon20serves as a compression reservoir35. When the balloon20is expanded, the pressure of the balloon20against the vessel wall causes compression of the compression reservoirs35. This in turn forces fluid from the compression reservoirs35into the areas of the rolled sections. When this happens, the rolled sections unroll to become unrolled sections39as shown inFIG. 4. Thus, when the balloon20is expanded to its expanded configuration and the outer surface22of the balloon20presses against the wall6of the vessel4, the compression reservoir35is compressed to a compressed condition. Compression of the compression reservoir35to its compressed condition causes the tube33to unroll from its rolled configuration to its unrolled configuration.

The medical device11shown inFIG. 4is shown being deployed at a bifurcation of the vessel4having a side branch8. The tubes33of the drug delivery extension31, when deployed, can extend into the side branch8to deliver therapeutic agent into the side branch8.

While only two tubes33are shown inFIG. 4, it will be appreciated that the medical device31may comprise a series of tubes33to extend around the inner periphery of the side branch8. The tubes may be varied in number, size and/or shape as described herein. Alternatively, the drug delivery extension need not be one or more tubes but can instead be a suitable structure designed to deliver therapeutic agent to an area beyond the outer surface22of the balloon20. For example, the drug delivery structure can be a single tube having a diameter approximating that of the side branch.

In a similar manner to that described in connection withFIGS. 1-3, the portion of each tube33extending along the outer surface22of the balloon20may have various configurations (e.g., straight, helical, etc.). Additionally, the compression reservoir35may be a portion of the tube33itself or a separate component, as described herein. Also, the therapeutic agent may be located on the outside of the tubes33or on the inside the tubes33and may be deployed as described herein.

A medical device like that shown inFIG. 4can be used in a similar manner to that described herein with reference toFIGS. 1-3. The balloon, in its collapsed configuration, is delivered to the constriction in the vessel. Techniques such as those known in the art can be used to position the balloon at the desired site, adjacent the side branch. The balloon is expanded for dilatation of the constriction. At or around this time, the drug delivery extension is deployed to deliver the therapeutic agent into the side branch, beyond the outer surface of the balloon. In the example as shown inFIG. 4in which tubes33have compression reservoirs35that are compressed when they are pressed by the balloon20against the wall6of the vessel4, the step of expanding the balloon20to cause the outer surface22of the balloon20to press against the wall6of the vessel4also compresses the compression reservoirs35and causes the deployment of the drug delivery extension31into the side branch8.

When the therapeutic agent is on the outside of the tubes33, the unrolling of the tubes33causes the therapeutic agent to contact the vessel wall and thereby be delivered to areas of the vessel wall in the side branch. Similarly, when therapeutic agent is forced out of the interior of tubes33upon deployment of the tubes33, such action also can cause the therapeutic agent to be delivered to areas of the vessel wall in the side branch.

FIGS. 5-7show a medical device12according to another embodiment of the disclosure. The medical device12, like that inFIGS. 1-3, comprises a catheter14with a balloon20located at a distal end16of the catheter14, which may be similar to the catheter14and balloon20as described herein in connection withFIGS. 1-3.

InFIGS. 5-7, the medical device12has a drug delivery extension40comprising a plurality of elongate members42configured to extend beyond the outer surface22of the balloon20when the balloon20is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface22of the balloon20. InFIG. 7, when the drug delivery extension40is deployed, the drug delivery extension40extends proximally from a proximal end24of the outer surface22of the balloon20.

InFIGS. 5-7, each elongate member42has an undeployed, collapsed configuration, as shown inFIG. 5, and a deployed, expanded configuration, as shown inFIG. 7. As can be seen inFIG. 7, when an elongate member42is in its deployed configuration, the elongate member42extends beyond the outer surface22of the balloon20and can expand to the wall of the vessel, and, in this way, the elongate member42can deliver therapeutic agent to an area of the vessel wall beyond the outer surface22of the balloon20.

As can be seen in the cross-sectional view ofFIG. 6, eight elongate members42are shown in this example, but more or fewer elongate members42may be used. The elongate members42may be of any suitable size or shape and need not be rectangular in cross-section. For example, the cross-sectional shape of the elongate members42may be oval, circular, square, or another suitable shape. The elongate members42may be overlapping in their collapsed state.

Similar to the tubes as described herein, the elongate members42may be coated with, or may otherwise carry, a therapeutic agent. In this manner, when the elongate members42are deployed to their expanded configuration as shown inFIG. 7against the vessel wall, the therapeutic agent can be delivered to the vessel wall.

The medical device12shown inFIGS. 5-7further comprises an actuation mechanism45for deploying the elongate members42from the collapsed configuration to the expanded configuration. The actuation member45in this embodiment comprises a ring46and a deployment wire47.

In the undeployed condition, as illustrated inFIG. 5, the ring46is located at a proximal position distanced away from the balloon20. In this position, the elongate members42are maintained in their collapsed configuration. To deploy the elongate members42, the ring46in this embodiment can be moved distally toward the balloon20, causing the elongate members42to bend outwardly to the expanded configuration, as shown inFIG. 7. The ring46may be moved by an operator causing deployment wire47to advance distally thereby causing the ring46to advance distally.

A medical device12such as that shown inFIGS. 5-7may be used in the following manner. The balloon20, in its collapsed configuration, is delivered to a constriction in the vessel. Techniques such as those known in the art can be used to position the balloon20at the desired site. Once the balloon20is at the constriction, the balloon20is expanded from its collapsed configuration to its expanded configuration. When sufficiently expanded, the outer surface22of the balloon20presses against the wall of the vessel for dilatation of the constriction. At or around this time, the drug delivery extension40is deployed to deliver the therapeutic agent to an area beyond the outer surface of the balloon. In the example ofFIGS. 5-7, the operator can advance the deployment wire47distally, causing the ring46to advance distally, which moves the elongate members42to the expanded configuration.

InFIG. 7, when the therapeutic agent is on the outside of the elongate members42, the expansion of the elongate members42against the vessel wall can cause the therapeutic agent to contact the vessel wall and thereby deliver therapeutic agent to areas of the vessel wall proximal to the balloon20. A similar configuration may be used to deliver therapeutic agent distal to the balloon20.

In certain situations, it may be desirable to utilize a drug delivery sheath located on the outside of the drug delivery extension. In the example ofFIGS. 5-7, a drug delivery sheath may be located on the outside of the elongate members42. The therapeutic agent can be located on the sheath, such that when the drug delivery extension is deployed, the drug is delivered from the sheath to the vessel wall.

FIGS. 8-11show a medical device13according to another embodiment of the disclosure. The medical device13, like other embodiments described herein, comprises a catheter14with a balloon20located at a distal end16of the catheter, which may be similar to the catheter and balloon as described with respect toFIGS. 1-3.

InFIGS. 8-11, the medical device13has a drug delivery extension50configured to extend beyond the outer surface22of the balloon20when the balloon20is in its expanded configuration in order to deliver the therapeutic agent to an area beyond the outer surface22of the balloon20. InFIG. 11, when the drug delivery extension50is deployed, the drug delivery extension50extends proximally and/or distally from one or both ends of the outer surface22of the balloon20.

InFIGS. 8-11, the drug delivery extension50comprises an expandable structure52. The expandable structure52has a collapsed configuration, as shown inFIG. 8, and an expanded configuration, as shown inFIG. 11. As can be seen inFIG. 11, when the expandable structure52is in its deployed, expanded configuration, the expandable structure52extends beyond the outer surface22of the balloon20, and, in this way, the expandable structure52delivers the therapeutic agent to an area beyond the outer surface22of the balloon20.

The expandable structure52may be any suitable shape. In the example illustrated inFIGS. 8-11, the expandable structure52comprises a series of longitudinal elements54and expansion rings56(only one expansion ring56is illustrated, but it will be appreciated that an expansion ring56may be positioned proximal to the proximal end of the balloon and/or distal of the distal end of the balloon). In the unexpanded configuration, which is shown inFIG. 8and in the enlarged end view ofFIG. 10, the expansion rings56can have a generally wave-like configuration and a reduced diameter. In the expanded configuration, shown inFIG. 11, the expansion rings56are enlarged. The expansion rings56can then have a stretched out wave-like configuration with an extended wavelength or a generally circular configuration as shown inFIG. 11.

In the embodiment illustrated inFIGS. 8-11, the longitudinal elements54and expansion rings56of the expandable structure52are in the form of tubes filled with fluid, similar to tubes described herein with respect toFIGS. 1-3. In this form, the portions of the longitudinal elements54extending along the outer surface22of the balloon20can serve as a compression reservoir, as described herein with respect toFIGS. 1-3. When the balloon20is expanded to its expanded configuration and the compression reservoir is pressed by the balloon20against the wall of the vessel, the compression reservoir is compressed to a compressed condition, thereby forcing fluid into the expansion ring(s), causing the expandable structure52to expand.

As can be seen in the cross-sectional view ofFIG. 9, three longitudinal elements54are shown in this example, but more or fewer longitudinal elements54may be used. The longitudinal elements54and expansion rings56may be any suitable size or shape and need not be circular in cross-section. For example, the cross-sectional shape of the longitudinal elements54and/or expansion rings56may be oval, rectangular, square, or another suitable shape.

Similar to the tubes as described with respect toFIGS. 1-3, the expandable structure52may be coated with, or may otherwise carry, a therapeutic agent. In this manner, when the expandable structure52is deployed to its expanded configuration as shown inFIG. 11against the vessel wall, the therapeutic agent can be delivered to the vessel wall.

In certain situations, it may be desirable to utilize a drug delivery sheath60located on the outside of the drug delivery extension. In the example ofFIGS. 8-11, a drug delivery sheath60may be located on the outside of the expandable structure52(the sheath60is not shown inFIGS. 9 and 10). The therapeutic agent can be located on the sheath60, such that when the drug delivery extension is deployed, the drug is delivered from the sheath60to the vessel wall. That is, when the sheath60is expanded to contact the vessel wall, the drug elutes from the sheath60to the vessel wall.

A medical device13such as that shown inFIGS. 8-11may be used in the following manner. The balloon20, in its collapsed configuration, is delivered to a constriction in the vessel. Techniques such as those known in the art can be used to position the balloon at the desired site. Once the balloon20is at the constriction, the balloon20is expanded from its collapsed configuration to its expanded configuration. When sufficiently expanded, the outer surface22of the balloon20presses against the wall of the vessel for dilatation of the constriction. At or around this time, the drug delivery extension50is deployed to deliver the therapeutic agent to an area beyond the outer surface22of the balloon20. In the example ofFIGS. 8-11, in which the expandable structure52has a compression reservoir that is compressed when it is pressed by the balloon20against the wall of the vessel, the step of expanding the balloon20to cause the outer surface22of the balloon20to press against the wall of the vessel also compresses the compression reservoir and causes the deployment of the drug delivery extension50.

An expandable structure such as expandable structure52may be expanded in other ways. For example, the expandable structure may be formed of a shape-memory material that is activated by heat. Alternatively, the expandable structure may be a self-expanding structure that is held in a sheath during delivery and released from the sheath for deployment. Similarly, the tubes and/or elongate members in other embodiments described herein may similarly be formed of shape-memory and activated by heat for deployment and/or otherwise constructed to be self-expanding.

The therapeutic agent used in embodiments of the present disclosure may be a pharmaceutically-acceptable agent such as a drug, a non-genetic therapeutic agent, a biomolecule, a small molecule, or cells. Example drugs include anti-proliferative agents or anti-restenosis agents such as paclitaxel, sirolimus (rapamycin), tacrolimus, everolimus, and zotarolimus.

Exemplary biomolecules include peptides, polypeptides and proteins; oligonucleotides; nucleic acids such as double or single stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), and ribozymes; genes; carbohydrates; angiogenic factors including growth factors; cell cycle inhibitors; and anti-restenosis agents. Nucleic acids may be incorporated into delivery systems such as, for example, vectors (including viral vectors), plasmids or liposomes.

Non-limiting examples of proteins include serca-2 protein, monocyte chemoattractant proteins (MCP-1) and bone morphogenic proteins (“BMPs”), such as, for example, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (VGR-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, and BMP-15. Preferred BMPs are any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, and BMP-7. These BMPs can be provided as homodimers, heterodimers, or combinations thereof, alone or together with other molecules. Alternatively, or in addition, molecules capable of inducing an upstream or downstream effect of a BMP can be provided. Such molecules include any of the “hedgehog” proteins, or the DNAs encoding them. Non-limiting examples of genes include survival genes that protect against cell death, such as anti-apoptotic Bcl-2 family factors and Akt kinase; serca 2 gene; and combinations thereof. Non-limiting examples of angiogenic factors include acidic and basic fibroblast growth factors, vascular endothelial growth factor, epidermal growth factor, transforming growth factors α and β, platelet-derived endothelial growth factor, platelet-derived growth factor, tumor necrosis factor α, hepatocyte growth factor, and insulin-like growth factor. A non-limiting example of a cell cycle inhibitor is a cathespin D (CD) inhibitor. Non-limiting examples of anti-restenosis agents include p15, p16, p18, p19, p21, p27, p53, p57, Rb, nFkB and E2F decoys, thymidine kinase and combinations thereof and other agents useful for interfering with cell proliferation.

Exemplary small molecules include hormones, nucleotides, amino acids, sugars, and lipids and compounds having a molecular weight of less than 100 kD.

Exemplary cells include stem cells, progenitor cells, endothelial cells, adult cardiomyocytes, and smooth muscle cells. Cells can be of human origin (autologous or allogenic) or from an animal source (xenogenic), or genetically engineered. Non-limiting examples of cells include side population (SP) cells, lineage negative (Lin−) cells including Lin−CD34−, Lin−CD34+, Lin−cKit+, mesenchymal stem cells including mesenchymal stem cells with 5-aza, cord blood cells, cardiac or other tissue-derived stem cells, whole bone marrow, bone marrow mononuclear cells, endothelial progenitor cells, skeletal myoblasts or satellite cells, muscle derived cells, go cells, endothelial cells, adult cardiomyocytes, fibroblasts, smooth muscle cells, adult cardiac fibroblasts+5-aza, genetically modified cells, tissue engineered grafts, MyoD scar fibroblasts, pacing cells, embryonic stem cell clones, embryonic stem cells, fetal or neonatal cells, immunologically masked cells, and teratoma derived cells. Any of the therapeutic agents may be combined to the extent such combination is biologically compatible.

The foregoing description and examples have been set forth merely to illustrate the disclosure and are not intended to be limiting. Each of the disclosed aspects and embodiments of the present disclosure may be considered individually or in combination with other aspects, embodiments, and variations of the disclosure. Modifications of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art and such modifications are within the scope of the present disclosure.