Patent Description:
The following disclosure relates to the field of medical balloons. In particular, it relates to medical balloons for use in the coronary arteries and other vessels of the body, including a drug-coated balloon (DCB) and a drug-releasing balloon that can be used for drug delivery in the coronary arteries and in other vascular beds and structures in the body.

Coronary artery disease remains the number one cause of death for both men and women in the developed world. In the United States, an estimated <NUM>,<NUM> Americans die of cardiovascular disease each year; the most common form of cardiovascular disease being coronary artery disease (CAD). About <NUM>,<NUM> people in the United States suffer heart attacks each year. Current percutaneous therapeutic options center around conventional coronary balloon angioplasty and stenting. However these techniques have several limitations. Conventional balloon angioplasty without stent insertion has very limited long-term patency. Current generation coronary drug-eluting stents have improved durability and patency but these devices remain limited by in-stent restenosis and stent thrombosis resulting in recurrent cardiovascular events. Percutaneous treatment options for in-stent restenosis are also limited and include balloon angioplasty and repeat stenting, both of which often have poor long-term patency. Second, stenting often limits future surgical revascularization options. Finally, a subset of coronary artery lesions including small vessel disease, bifurcation lesions and ostial lesions remain a significant challenge for interventional cardiologists due to the complexity of these lesions and unfavorable anatomy. Bifurcation stenting using a two-stent strategy (one stent in the main vessel and an overlapped stent from the main vessel into the side branch) can result in unacceptably high rates of in-stent restenosis with limited future percutaneous options.

Drug-coated balloons (often referred to as "DCBs" or drug-eluting balloons) have been studied in the coronary arteries given the success of drug-coated balloon technology in the peripheral vascular space. Coronary DCBs have primarily been studied in cases of in-stent restenosis, bifurcation lesions, and small vessel lesions. In order for adequate antiproliferative drug elution into the vascular architecture, DCB inflations need to be longer in duration (minimum <NUM>-<NUM> seconds) compared to balloon inflations performed during conventional coronary angioplasty (typically less than <NUM> seconds). During the extended balloon inflation period, myocardial blood flow ceases and ischemia occurs which can lead to cardiac dysrhythmias, angina, and even hemodynamic instability depending on lesion location and the patient's clinical condition. These issues are concerning to practicing interventionalists, particularly when treating high-risk lesions such as lesions in the proximal coronary arteries (e.g., left anterior descending [LAD] artery and large dominant right coronary artery [RCA]). Thus, the use of drug-coated balloons to treat CAD has been met with significant skepticism. <CIT> discloses a balloon having a plurality of lumens through which to access either the distal end of the catheter shaft or internal body locations. <CIT> discloses an inflatable structure formed of a plurality of balloons arranged radially around a central location.

In order to address the concern of prolonged ischemia during balloon inflation, a need exists for a drug-coated balloon that does not occlude blood flow when inflated for drug elution into the vessel architecture. A need further exists, for both semi-compliant and non-compliant versions of the non-occluding drug-coated balloon in order to appropriately treat a wide array of coronary artery lesions commonly seen in clinical practice.

The present invention relates a non-occluding medical balloon and a method for fabricating a non-occluding medical balloon as claimed hereafter. Preferred embodiments are set forth in the dependent claims, A novel drug-coated balloon is provided that is non-occluding when inflated for drug elution. One embodiment of the new drug-coated balloon can be produced in two versions (analogous to conventional coronary balloons), namely: <NUM>) a semi-compliant balloon version believed to be particularly suitable for treatment of de novo lesions; and <NUM>) a noncompliant, balloon version believed to be particularly suitable for treatment of in-stent restenosis. Both versions of this embodiment include a central lumen for the guidewire. Upon inflation, the balloon takes on a "Mercedes-Benz" sign appearance in cross section with three lumens or channels created allowing for passive movement of blood through the balloon during delivery of a drug coated on the balloon. The drug coating can include Paclitaxel, which has been widely studied and used in previous coronary drug-eluting stents and current-generation peripheral arterial DCBs. The blood flow through the lumen(s) of the fully inflated balloon allows for safer and more prolonged balloon inflation times to occur in order to maximize delivery of Paclitaxel or other drugs to the vessel wall and thus increased efficacy of the drug. The balloon can be particularly useful in treating more proximal lesions including proximal bifurcation lesions (e.g. LAD and first diagonal branch).

In one aspect thereof, a non-occluding drug-coated balloon catheter device for use in a blood vessel transporting blood comprises a catheter shaft including a guidewire lumen, a fluid lumen and a connector port. A balloon is mounted on the catheter shaft and includes an outer envelope surrounding the guidewire lumen in fluid communication with the fluid lumen; a drug coating applied on the exterior surface of the outer envelope; and at least one bypass lumen forming a passage extending from the proximal end of the outer envelope to the distal end of the outer envelope. When the balloon is positioned in a blood vessel and inflated, the exterior surface of the drug-coated outer envelope presses the drug coating against the blood vessel wall, while the bypass lumen is open between the distal end of the outer envelope and the proximal end of the outer envelope such that passive blood transport continues through the bypass lumen.

In one embodiment, the balloon is a semi-compliant balloon.

In another embodiment, the balloon is a non-compliant balloon.

In another aspect of the disclosure, a method for fabricating a non-occluding medical balloon for use on a catheter device comprises providing a balloon preform having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall, blowing the balloon preform into an expanded balloon, filling the balloon with a support medium, sealing, at each end of the balloon, the passage walls together across a portion of the inflation passage and cutting a hole through sealed portion to form a perfusion port, and removing the support medium.

In still another aspect of the disclosure. a method for fabricating a non-occluding medical balloon for use on a catheter device comprises providing a balloon preform having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall, blowing the balloon preform into an expanded balloon, supporting the inner surface of the expanded balloon, sealing, at each end of the balloon, the passage walls together across a portion of the inflation passage and forming a perfusion port through the sidewall into the central passage, and removing the support from the inner surface of the balloon.

In one embodiment, the method further comprises coating the outer surface of the balloon with a drug-eluting coating.

In another embodiment, the method further comprises boring a plurality of micro-pores through the outer surface of the balloon into the at least one inflation passage.

In yet another embodiment, boring the plurality of micro-pores is performed before removing the support medium.

In still another embodiment, boring the plurality of micro-pores is performed after removing the support medium.

In yet another embodiment, supporting the inner surface of the expanded balloon further comprises filling the central cavity of the balloon with conforming support medium and sealing the passage walls together across a portion of the inflation passage and forming a perfusion port through the sidewall further comprises pressing the inflation passage walls together across a portion of the inflation passage against the support medium, sealing a portion of the pressed-together passage walls, and cutting a hole through a portion of the sealed portion.

In a further embodiment, sealing, at each end of the balloon, the passage walls together across a portion of the inflation passage and cutting a hole through sealed portion further comprises sealing the passage walls together and cutting a hole through the sealed portion with a single tool.

In a yet further embodiment, sealing, at each end of the balloon, the passage walls together across a portion of the inflation passage and cutting a hole through sealed portion further comprises sealing the passage walls together with a first tool, and cutting a hole through the sealed portion with a second tool.

In a still further embodiment, the balloon preform includes a plurality of discrete inflation passages disposed between the inner and outer surfaces of the sidewall.

In a still further embodiment, the method further comprises removing at least a portion of the end cone from the blown balloon to expose the inflation passage and inserting a first end of a preformed inflation lumen into the inflation passage of the balloon body. Supporting the inner surface of the expanded balloon further comprises inserting a first mandrel into the central cavity of the balloon and inserting a second mandrel into the preformed inflation lumen. Sealing the passage walls together across a portion of the inflation passage and forming a perfusion port through the sidewall further comprises sealing the first end of the preformed inflation lumen into the inflation passage and sealing the remaining portions of the inflation passage along the edge to one another.

In yet another aspect of the disclosure, a non-occluding medical balloon apparatus comprises a proximal preform portion including a sidewall having an outer surface, an inner surface defining a central passage, and at least one inflation passage disposed between the outer and inner surfaces, a nosecone defining an extension of the central passage, and an expanded balloon portion disposed between, and connected to, the proximal preform portion and the nosecone. The expanded balloon portion includes a substantially cylindrical central portion having a nominal diameter that is greater than a proximal diameter of the proximal preform portion and greater than a distal diameter of the nosecone, a proximal end portion connected between the central portion and the proximal preform portion and tapering from the nominal diameter of the central portion to the proximal diameter of the proximal preform portion, and a distal end portion connected between the central portion and the nosecone and tapering from the nominal diameter of the central portion to the distal diameter of the nosecone. Each of the proximal end portion, central portion and distal end portion include respective expanded sidewalls having respective expanded outer surfaces, respective expanded inner surfaces defining respective expanded central passages, and at least one respective expanded inflation passage disposed between the respective outer and inner expanded surfaces. Each inflation passage of the proximal preform portion is in fluid communication with a corresponding expanded inflation passage of the expanded balloon portion. On each of the proximal and distal end portions of the expanded balloon portion, areas of the outer and inner sidewalls are sealed together, and within each sealed-together area of the outer and inner sidewalls, a hole is cut through the sidewall into the expanded central passage to form perfusion port. A fluid-tight guide wire lumen is disposed through the central passage of the proximal preform portion, the respective expanded central passages of the balloon portion and the central passage of the nose cone.

In one embodiment, the proximal preform portion comprises multiple inflation lumens separated by preform septums, the expanded balloon portion comprises multiple expanded inflation lumens separated by balloon septums, and the respective inflation lumens are in fluid communication with the respective expanded inflation lumens.

In another embodiment, the non-occluding medical balloon apparatus further comprises a drug-eluting coating disposed on the outer surface of the central portion of the balloon.

In yet another embodiment, the drug-eluting coating comprises any drug including, but not limited to, the drug Paclitaxel.

In still another embodiment, the non-occluding medical balloon apparatus further comprises a plurality of micro-pores formed through the outer surface of the sidewall into the inflation passage.

In a further embodiment, the dimensions of the micro-pores (denoted by subscript "MP") include a length LMP and a diameter DMP, which are selected relative to the surface tension and/or viscosity of a fluid medium within the inflation passage such that the fluid medium is not released from the micro-pores until a predetermined pressure differential DPMP is present between the inflation passage and the exterior of the balloon.

In a yet further embodiment, the non-occluding medical balloon apparatus further comprises a catheter shaft attached to the proximal preform of the balloon, the catheter shaft including a guide wire lumen and an inflation lumen. The guide wire lumen of the catheter shaft is connected to the guidewire lumen of the balloon. The inflation lumens of the catheter shaft are connected to the inflation lumens of the balloon.

For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:.

Referring to <FIG>, there is illustrated a non-occluding cardiovascular drug-coated balloon and catheter shaft device <NUM> in accordance with one embodiment. The device <NUM> includes a non-occluding balloon <NUM> operatively mounted on a catheter shaft <NUM>. In the embodiment shown, the catheter shaft <NUM> is of the rapid exchange type, having a guidewire lumen <NUM> extending from a distal end <NUM> of the shaft to a notch or wire exit <NUM> located along the shaft. The shaft <NUM> further includes a proximal hypotube <NUM> extending from the vicinity of the notch <NUM> to a fill port connector <NUM> at a proximal end <NUM> of the shaft. The balloon <NUM> is mounted over the distal portion of the guidewire lumen <NUM> and the distal end of the balloon forms a fluid-tight seal against the guidewire lumen. Radio-opaque markers <NUM> can be mounted on the guidewire lumen <NUM> to indicate the proximal and distal ends of the balloon <NUM> during x-ray imaging. In some embodiment, a tapered tip <NUM> is attached to the distal end <NUM> of the shaft. A fluid lumen <NUM> connects the hypotube <NUM> to the proximal end of the balloon <NUM>, forming a fluid-tight path from the connector <NUM> to the interior of the balloon. Saline, contrast solution or other inflation fluid or inflation medium can be introduced into the connector <NUM> to inflate the balloon <NUM> via the hypotube <NUM> and fluid lumen <NUM>. The fluid can be subsequently withdrawn from the connector <NUM> to deflate the balloon <NUM>. Although a rapid-exchange type catheter shaft <NUM> is used in the illustrated embodiment of the device <NUM>, other types of catheter shafts (e.g., over-the-wire type) can be used with the non-occluding balloon <NUM>.

The non-occluding balloon <NUM> includes an outer envelope <NUM> having a drug coating <NUM> (see <FIG>) on an exterior surface <NUM> and one or more bypass lumens <NUM> disposed inside the outer envelope having openings on the proximal and distal ends of the outer envelope. For purposes of illustration, the drug coating <NUM> is shown on only a portion of the exterior surface <NUM> of the outer envelope <NUM>, but it will be understood that the drug coating covers substantially the entire exterior surface. Prior to balloon inflation, the outer envelope <NUM> is folded around the catheter shaft so that the majority of the exterior surface <NUM> is not exposed and the drug coating <NUM> is protected from being washed away during transit through the body to the treatment site. Upon inflation of the balloon <NUM>, the outer envelope <NUM> expands and presses the entire exterior surface <NUM> with the drug coating <NUM> (now fully exposed) against the adjacent vascular architecture (not shown) so that the drug coating can elute from the balloon onto the tissue for treatment. While the balloon <NUM> is inflated, the bypass lumens <NUM> (extending between the proximal and distal ends of the outer envelope <NUM>) are open to allow blood to flow through the balloon (i.e., through the bypass lumens), thereby preventing arterial occlusion.

Referring to <FIG>, further details of the non-occluding drug-coated balloon <NUM> are provided. Each bypass lumen <NUM> is formed by a bypass lumen wall <NUM> attached to the proximal end of the outer envelope <NUM> to form a proximal bypass opening <NUM> and attached to the distal end of the outer envelope to form a distal bypass opening <NUM>. The configuration of the bypass lumens <NUM> can form spoke passages <NUM> extending between the central portion <NUM> of the balloon (near the guidewire lumen <NUM>) and the rim portion <NUM> (near the outer envelope <NUM>). During inflation of the balloon <NUM>, inflation fluid enters the balloon from the fluid lumen <NUM>, flows from the central portion <NUM> through the spoke passages <NUM> and into the rim portion <NUM> to fully expand the outer envelope <NUM>. In the illustrated embodiment, three wedge-shaped bypass lumens <NUM> are provided, forming a "three-pointed star" design or "Mercedes-Benz" design when viewed in cross-section. In other embodiments, different numbers of bypass lumens having different cross-sectional shapes can be used.

The non-occluding drug-coated balloon <NUM> can be constructed of polymer materials including polyether block amide (also known as "PEBA") and polyamides such as nylon. In some embodiments, the ends of the bypass lumens <NUM> can be joined to the outer envelope <NUM> using glues or adhesives, by solvent welding or by thermal welding.

Referring now specifically to <FIG>, in a first embodiment, the wall <NUM> of the outer envelope <NUM> can be formed of PEBAX <NUM> polyether block amide material having a certain thickness and the walls <NUM> of the bypass lumens <NUM> can be formed of PEBAX <NUM> polyether block amide material having a greater thickness. The PEBAX <NUM> material of the bypass lumen walls <NUM> is stiffer (i.e., less compliant) than the PEBAX <NUM> material of the outer envelope wall <NUM>. This configuration can yield a balloon <NUM> that is semi-compliant. In one example, a semi-compliant balloon having a nominal diameter of <NUM> at a nominal pressure of <NUM>-<NUM> atmospheres can be expected to have a final diameter of <NUM> at the burst pressure of <NUM> atmospheres.

In a second embodiment, the wall <NUM> of the outer envelope <NUM> can be formed of PEBAX <NUM> polyether block amide material having a thickness of <NUM> and the walls <NUM> of the bypass lumens <NUM> can also be formed of PEBAX <NUM> polyether block amide material having a certain thickness. In this embodiment, the material of the bypass lumen walls <NUM> is the same as that of the outer envelope wall <NUM>. This configuration can yield a balloon <NUM> that is non-compliant. In one example, a non-compliant balloon having a nominal diameter of <NUM> at a nominal pressure of <NUM> atmospheres can be expected to have a final diameter of <NUM> at the burst pressure of <NUM>-<NUM> atmospheres.

Some embodiments of the non-occluding drug-coated balloon <NUM> for use in coronary arteries can have a nominal length from <NUM> to <NUM>. In other embodiments, the balloon <NUM> can have a nominal length from <NUM> to <NUM>. Some embodiments of the non-occluding drug-coated balloon <NUM> for use in coronary arteries can have a nominal diameter from <NUM> to <NUM>. In other embodiments, the balloon <NUM> can have a nominal diameter from <NUM> to <NUM>.

In addition to the embodiments described above, other embodiments of the non-occluding balloon can have different lengths and/or wall thicknesses and be made of materials including, but not limited to, polyether block amide (e.g., PEBAX® brand by Arkema or Vestamid® E brand by Evonik Industries), polyamides such as nylon, urethane, polyester and polyethylene terephthalate ("PET") and other materials known for use in semi-compliant and non-compliant medical balloons. By selection of the appropriate dimensions and materials, as is known for producing conventional PTCA balloons and other medical balloons, non-occluding balloons in accordance with this disclosure can be produced having desired dimensions, nominal diameters, nominal pressures, final diameters and burst pressures.

Referring now to <FIG>, there is illustrated an alternative non-occluding drug-coated balloon <NUM>. The balloon <NUM> is substantially similar to the balloon <NUM> previously described, except the size of the bypass lumens <NUM> is different from that of the balloon <NUM>. Although the balloon <NUM> may allow less blood flow through the bypass lumens <NUM> than the balloon <NUM>, the blood flow is nevertheless sufficient to provide extended drug elution time before significant ischemia occurs. The different sizes of the bypass lumens <NUM> results in different sized central portion <NUM>, spoke passages <NUM> and/or outer rim portion <NUM>, which can provide different inflation and stability characteristics for the balloon <NUM>.

Referring now to <FIG>, there is illustrated another alternative non-occluding drug-coated balloon <NUM>. The balloon <NUM> is substantially similar to the balloons <NUM>, <NUM> previously described, except the number of bypass lumens <NUM> is different from that of the previous balloons. The different numbers of bypass lumens <NUM> result in different numbers and shapes of spoke passages <NUM>, which can provide different inflation and stability characteristics for the balloon <NUM>.

Referring now to <FIG>, there is illustrated another alternative non-occluding drug-coated balloon <NUM>. The balloon <NUM> is substantially similar to the balloons <NUM>, <NUM> and <NUM> previously described, except both the shape and the number of bypass lumens <NUM> is different from that of the previous balloons. In this embodiment, two bypass lumens <NUM> are provided, and the lumens have a circular cross section. The different shapes and numbers of bypass lumens <NUM> result in different numbers and shapes of spoke passages <NUM>, rim portion <NUM> and central portion <NUM>, which can provide different inflation and stability characteristics for the balloon <NUM>.

Referring now to <FIG>, there is illustrated a further alternative non-occluding drug-coated balloon <NUM>. The balloon <NUM> is substantially similar to the balloons <NUM>, <NUM>, <NUM> and <NUM> previously described, except both the shape and the number of bypass lumens <NUM> is different from that of the previous balloons. In this embodiment, only one bypass lumen <NUM> is provided, and the lumen has a crescent-shaped cross section. The different shapes and numbers of bypass lumen <NUM> results in different numbers and shapes of spoke passages <NUM>, rim portion <NUM> and central portion <NUM>, which can provide different inflation and stability characteristics for the balloon <NUM>.

Various processes to fabricate a non-occluding medical balloon are provided in accordance with additional aspects of the invention. In one embodiment, a non-occluding medical balloon with wedge shape windows cut and sealed from the cone region of the balloon consists of the following steps: (<NUM>) fabricate the balloon; (<NUM>) fill the balloon with a medium having the capability to fill and conform to the interior surface of the balloon and become a ridged substrate to act as a processing aid to allow a tool to press against the surface of the balloon and becoming compressed against the surface of the conforming processing aid; (<NUM>) use ultra-sonic energy to cut and seal the balloon (ultra-sonic energy is used because it will have very little radiant heat generated from the process which in turn will not heat effect the balloon); and (<NUM>) dissolve the conforming processing aid with a medium that does not exceed <NUM> degrees Celsius.

Referring now the <FIG>, there is illustrated a schematic diagram of a process <NUM> for fabricating a non-occluding medical balloon for drug delivery in accordance with aspects of the invention. At step <NUM>, a balloon preform is provided having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall. At step <NUM>, the balloon preform is blown into an expanded balloon. Processes for blow-molding medical balloons are known, and any such process can be used to blow the preform into a balloon (i.e., expanded balloon). Typically, only a center portion of the preform is expanded into the balloon, and the respective end portions of the preform remain relatively unexpanded. The unexpanded portions of the balloon are sometimes referred to as the "tails. " In some embodiments, the center portion of the balloon is fully expanded into a cylindrical configuration, and portions proximally and distally adjacent to the center portion are only partially expanded to transition between the tails and the center portion of the balloon. The partially expanded transitional portions of the balloon are sometimes referred to as the "cones" or "end cones. " In some embodiments, the step <NUM> can include heating the balloon preform. If heating is used, in many embodiments the blowing temperature will be limited to <NUM> degrees C or less. At step <NUM>, support is provided for the inner surface of the expanded balloon. In some embodiments the support can be provided by a removable conforming medium and in other embodiments the support can be provided by a removable structure such as a mandrel. At step <NUM>, at each end of the balloon, the inflation passage walls are sealed together across a portion of the inflation passage and a perfusion port (i.e., bypass lumen) is formed through the central passage of the balloon. At step <NUM>, the support is removed from the inner surface of the balloon. In some embodiments, the step <NUM> can include heating a conforming support medium and/or dissolving the support medium with an appropriate solvent. In other embodiments, the step <NUM> can include removing mandrels from the balloon. Additions steps can be included in process <NUM> to further adapt the non-occluding balloon for drug delivery. For example, in some embodiments, a drug-eluting coating can be applied to the outer surface of the non-occluding balloon. In other embodiments, micro-pores can be formed through the outer surface of the sidewall of the non-occluding balloon into the inflation passage to allow drug delivery by emission of drug-carrying inflation medium through the micro-pores as disclosed herein.

Referring now the <FIG>, there is illustrated a schematic diagram of another process <NUM> for fabricating a non-occluding medical balloon for drug delivery in accordance with aspects of the invention. At step <NUM>, a balloon preform is provided having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall. At step <NUM>, the balloon preform is blown into an expanded balloon. As disclosed above, processes for blow-molding medical balloons are known, and any such process can be used to blow the preform into a balloon. In some embodiments, the step <NUM> can include heating the balloon preform. If heating is used, in many embodiments the blowing temperature will be limited to <NUM> degrees C or less. At step <NUM>, the balloon is filed with a support medium. The support medium can be any medium that can conform to the inner surface of the balloon and be removed. Various removable media known for use in fabricating medical balloons can be used for the support medium including, but not limited to, solid materials having a melting temperature below the reflow temperature of the balloon material, solid materials soluble in solvents that do not attack the balloon material, and granular or particulate materials. At step <NUM>, at each end of the balloon, seal the passage walls together across a portion of the inflation passage and cut a hole through sealed portion to form a perfusion port (i.e., bypass lumen). At step <NUM>, the support medium is removed. In some embodiments, the step <NUM> can include heating the support medium and/or dissolving the support medium with an appropriate solvent. At step <NUM>, a drug-eluting coating is applied to the outer surface of the balloon. In other embodiments, in addition to, or instead of applying a drug-eluting coating to the outer surface of the balloon, micro-pores can be formed through the outer surface of the sidewall into the inflation passage to allow drug delivery by emission of drug-carrying inflation medium through the micro-pores as disclosed herein.

Referring now to <FIG>, there is illustrated a schematic diagram of yet another process <NUM> for fabricating a non-occluding medical balloon in accordance with aspects of the invention. At step <NUM>, a balloon preform is provided having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall. At step <NUM>, the balloon preform is positioned within a mold. At step <NUM>, the central passage of the balloon preform is pressurized to expand the sidewall against an inner surface of the mold to form the balloon. Typically, only a center portion of the preform is expanded when blowing the balloon, e.g., the central portion (i.e., the "cylinder") and adjacent transitional portions (i.e., the "cones"), and the respective end portions of the original preform remain relatively unexpanded in the balloon (i.e., forming the "tails"). In some embodiments, the step <NUM> can include heating the balloon preform and/or heating the mold. If heating is used, in many embodiments the temperature of the mold and/or preform will be limited to <NUM> degrees C or less. At step <NUM>, the expanded (i.e., "blown") balloon is removed from the mold. At step <NUM>, the central passage of the balloon is filled with a support medium conforming to the inner surface of the sidewall. The support medium can be any medium that can conform to the inner surface of the balloon and be removed. Various removable media known for use in fabricating medical balloons can be used for the support medium including, but not limited to, solid materials having a melting temperature below the reflow temperature of the balloon material, solid materials soluble in solvents that do not attack the balloon material, and granular or particulate materials. At step <NUM>, at each end of the balloon, the passage walls of the inflation passage are pressed together against the support medium and sealed together across a portion of the inflation passage. In some embodiments, the inflation passage walls pressed together and sealed are disposed on the cone ends of the balloon. At step <NUM>, at each end of the balloon, at least one hole is cut through the sealed-together passage wall portions into the central passage to form perfusion ports. At step <NUM>, the support medium is removed. In some embodiments, the step <NUM> can include heating the support medium and/or dissolving the support medium with an appropriate solvent.

Referring still to <FIG>, in some embodiments, the step <NUM> can also comprise: a balloon preform is provided having a sidewall defining a central passage and having a plurality of discrete inflation passages disposed between the inner and outer surfaces of the sidewall. In some embodiments, the step <NUM> can also comprise: the balloon preform is positioned within a mold having an inner surface defining a central portion between two end (e.g., cone) portions. In some embodiments, the step <NUM> can also comprise: the central passage of balloon preform is pressurized to expand balloon sidewall against the mold inner surface to form balloon having central portion between two end portions (e.g., end cone portions). Typically, only a central portion of the preform is expanded into the balloon, and the two end portions remain relatively unexpanded.

Referring now to <FIG>, there is illustrated a cross-sectional end view of an exemplary balloon preform <NUM> that can be used in the fabricating a non-occluding medical balloon in accordance the disclosure. The preform <NUM> includes a sidewall <NUM> having an outer surface <NUM> and an inner surface <NUM> defining a central passage <NUM>. Disposed in the sidewall <NUM> between the inner surface <NUM> and outer surface <NUM> is at least one inflation passage <NUM>. The respective outer and inner surfaces <NUM>, <NUM> of the sidewall <NUM> effectively constitute an outer sidewall and an inner sidewall where separated by the inflation passage <NUM>. The central passage <NUM> and inflation passages <NUM> can extend continuously through the balloon preform <NUM>. In the embodiment shown, the preform <NUM> includes three inflation passages <NUM>; however, other embodiments may have different numbers of inflation passages. In the embodiment shown, the each inflation passages <NUM> has a "sausage shaped" cross section; however, other embodiments may have inflation passages of different cross-sectional shapes, When the preform <NUM> includes multiple inflation passages <NUM>, the sidewall <NUM> can include septums <NUM> of continuous material extending from the inner surface <NUM> to the outer surface <NUM> between adjacent inflation passages.

The balloon preform <NUM> can be formed from materials including, but not limited to, PEBAX® brand polyether block amide, nylon and other polyamides, urethane, polyester, polyethylene terephthalate (PET) and other materials known for use in semi-compliant and non-compliant medical balloons. The balloon preform <NUM> is preferably formed by extrusion; however, other fabrication methods can be used including, but not limited to, machining, molding and casting.

Referring now to <FIG>, there is illustrated a cross-sectional end view of an exemplary expanded balloon <NUM> that can be formed from the balloon preform <NUM> and used in fabricating a non-occluding medical balloon in accordance the disclosure. As described above, the balloon preform <NUM> is blown into the balloon <NUM> according to known blow-molding processes. During the blow-molding process, the sidewall <NUM> of the preform <NUM> can reform (e.g., by stretching and/or expanding) into a sidewall <NUM> of the balloon <NUM>, and the original preform structures including outer surface <NUM>, inner surface <NUM>, central passage <NUM>, inflation passages <NUM> and septums <NUM> can reform into corresponding balloon structures including outer surface <NUM>, inner surface <NUM>, central passage <NUM>, inflation passages <NUM> and septums <NUM>. Similar to the preform <NUM>, the respective outer and inner surfaces <NUM>, <NUM> of the balloon sidewall <NUM> effectively constitute a balloon outer sidewall and a balloon inner sidewall where separated by the inflation passage <NUM>. The fully-expanded portion of the sidewall <NUM> (i.e., disposed in the central portion of the balloon) is denoted <NUM>' in <FIG>, whereas the partially-expanded portion of the sidewall (e.g., disposed on the end portions of the balloon and extending from the unexpanded portion of the preform <NUM> to the fully-expanded portion <NUM>') is denoted <NUM>". In <FIG>, an unexpanded end portion of the balloon preform <NUM> (shown in dashed line) can be seen behind the expanded balloon sidewall <NUM>". The central passage <NUM> of the balloon is relatively large (denoted <NUM>') in the central portion of the balloon and relatively small (denoted <NUM>") near the preform <NUM>, expanding therebetween in the end portions of the balloon. View line <NUM>-<NUM> (denoted by arrow <NUM>) denotes a region on the end portion of the balloon sidewall <NUM>" where the simplified cross-sections are taken for <FIG> described below.

Referring now to <FIG>, a series of simplified cross-sectional views through the end portion sidewall <NUM>" of the balloon <NUM> are provided to further illustrate the process of forming a non-occluding medical balloon in according with this disclosure. For purposes of simplified illustration, the end portion sidewalls in <FIG> are depicted as straight, although in actuality the sidewalls can be curved as shown in <FIG>.

Referring first to <FIG>, a portion of the end sidewall <NUM>" is shown extending between two septums <NUM>. The inflation passage <NUM> is disposed between the outer and inner surfaces <NUM>, <NUM> of the sidewall <NUM>" (i.e., the balloon outer and inner sidewalls). In the illustration, the inflation passage <NUM> is illustrated with the outer sidewall surface <NUM> spaced-apart from inner sidewall surface <NUM>; however, in some embodiments the inflation passage may be collapsed such that the outer and inner sidewall surfaces <NUM>, <NUM> are touching one another (but not bonded together).

Referring next to <FIG>, the inner portion of the balloon (i.e., the central channel <NUM>) is filled with a support medium <NUM> that conforms to the inner surface <NUM> of the sidewall <NUM>". The support medium <NUM> provides support for the inner surface <NUM> of the sidewall.

Referring next to <FIG>, an area of the outer surface (i.e., outer sidewall) <NUM> of the sidewall <NUM>" is pressed by an external force (denoted by arrow <NUM>) across the inflation passage <NUM> towards an underlying area of the inner surface (i.e., inner sidewall) <NUM>. Since the inner surface <NUM> is supported by the support medium <NUM> and cannot move away, the external force <NUM> can press areas of the outer surface <NUM> into contact with areas of the inner surface <NUM>. In the embodiment shown in <FIG>, a tool <NUM> is used to apply the external force <NUM> pressing the outer surface <NUM> against the inner surface <NUM>; however, in other embodiments the pressing can be provided by other means including, but not limited to, the application of pressurized fluids including air, inert gas and/or water.

Referring next to <FIG>, while an area of the outer surface <NUM> is pressed into contact with an area of the inner surface <NUM>, at least a portion of the pressed-together areas are sealed or fused to one another to produce a sealed portion, denoted <NUM>. The sealing or fusing can be performed by heating, melting, welding or otherwise joining the respective areas of surfaces <NUM> and <NUM> to one another to form a pressure-tight bond in the sealed area <NUM>. Preferably, any application of heat to the area of the sealed portion <NUM> is rapid and localized to minimize effects to the surrounding areas of the balloon sidewall <NUM>". In some embodiments, the tool <NUM> both presses the sidewall surfaces <NUM> and <NUM> together and creates the seal. For example, in various embodiments the tool <NUM> can be a heated tool, a sonic (including ultrasonic) welding tool, a radio frequency (RF) welding tool or other known tools for joining balloon materials. In other embodiments, one mechanism (e.g., a tool or compressed fluid) can be used to press the sidewall surfaces <NUM> and <NUM> together while a second tool (not shown) produces the seal. For example, the second tool can be a heat tool, a sonic/ultrasonic welding tool, a RF welding tool, a microwave welding tool or a laser welding tool. A portion of the inflation passage <NUM> remains open after the sealed portion <NUM> is created. In the embodiment illustrated in <FIG>, the inflation passage <NUM> remains open on both sides of the sealed portion <NUM>; however, in other embodiments, the inflation passage can remain open on only one side of the sealed portion. In yet other embodiments, multiple sealed portion <NUM> can be created in the inflation passage <NUM> between two septums <NUM>, and multiple portions of the inflation passage can remain open between such sealed portions.

Referring next to <FIG>, after creating the sealed portion <NUM>, an area (denoted <NUM>) within the sealed portion can be cut away, creating a hole <NUM> entirely through the sidewall <NUM>" into the central passage <NUM> of the balloon <NUM>. This hole <NUM> will be the perfusion port (i.e., bypass lumen) of the non-occluding balloon. The remaining (i.e., uncut) portions of the sealed portion (denoted <NUM>') completely surround the hole <NUM> such that the edges of the outer and inner surfaces <NUM> and <NUM> remain sealed together and the remaining inflation passages <NUM> remain fluid-tight. The cutting of the area <NUM> of the sealed portion <NUM> can be performed using known mechanical cutting mechanisms including knives, cutting blades or punches, or using known thermal cutting mechanisms including heated tools, or using known laser cutting or laser ablation mechanisms. In some embodiments, the same tool <NUM> can be used to perform pressing, sealing and cutting operations. In other embodiments, different tools can be used for the various pressing, sealing and cutting operations. In some embodiments, the pressing, sealing and cutting operations can be performed simultaneously, whereas in other embodiments, the various pressing, sealing and cutting operations can be performed sequentially.

Referring next to <FIG>, after creating the hole <NUM> through the balloon sidewall <NUM>", the support medium <NUM> can be removed from the central passage <NUM> of the balloon <NUM>. The hole <NUM> now forms a perfusion port allowing for the ready passage of fluids such as blood (denoted by arrow <NUM>) from the exterior of the balloon (e.g., from a blood vessel or other body lumen) through the end sidewall <NUM>" and into the expanded central passage <NUM>'. Similar perfusion ports on the opposite end of the balloon <NUM> allow fluids <NUM> to exit the expanded central passage <NUM>' and return to the exterior of the balloon (e.g., back into the blood vessel or body lumen).

Referring now to <FIG>, the fabrication of an exemplary non-occluding medical balloon <NUM> in accordance with the disclosure is further illustrated and described. The balloon <NUM> is substantially similar in many respects to the balloon <NUM> previously described, therefore common reference numbers are used for similar elements. In the embodiment of <FIG>, the end sidewall <NUM>" includes three inflation passages <NUM> separated by three septums <NUM>. The inflation passages <NUM> and septums <NUM> can be seen at the exposed cross-sectioned surface and extending down (shown in dashed lines) the end portion of the balloon <NUM> to the unexpanded preform <NUM>. During fabrication of the balloon <NUM>, the central cavity <NUM> can be filled with support medium <NUM> conforming to the inner surface <NUM>; however, the support medium is not shown in <FIG> for clarity of illustration.

Referring still to <FIG>, three sealed portions <NUM> can be formed in the sidewall <NUM> by pressing the outer and inner surfaces <NUM> and <NUM> together across areas of the inflation passages <NUM> and sealing or fusing areas of the pressed-together surfaces to form a fluid-tight seal, for example as described in connection with <FIG>. Some portions (denoted <NUM>') of the inflation passage <NUM> are left unsealed between the sealed portion <NUM> and the septums <NUM> so that an inflation medium can travel through the sidewall <NUM> of the balloon around the sealed portions. An inner portion of each sealed area <NUM> can be selected to be cut out, as denoted by dashed line <NUM> in one portion.

Referring now to <FIG>, the balloon <NUM> is illustrated after the holes <NUM> are cut through the sealed portions <NUM> to create the perfusion ports, and after the support medium <NUM> is removed from the central passage <NUM>. As previously described, unsealed portions <NUM>' of the inflation passages remain between the sealed portions <NUM>' bordering the holes <NUM> and the septums <NUM> so that an inflation medium can travel from the unexpanded preform end portion <NUM>, up the proximal end portion sidewall <NUM>", through the central sidewall <NUM>' and into the distal end portion sidewall <NUM>", thereby inflating the balloon <NUM>. When the balloon <NUM> is fully expanded, the perfusion ports <NUM> through each end sidewall <NUM> allow fluids such as blood to flow through the central passage <NUM> of the balloon, thus allowing the balloon to be inflated against blood vessel/body lumen walls without occluding the flow of blood through the vessel or body lumen. In some embodiments, a drug-eluting coating <NUM> can be applied to the outer surface <NUM> of the balloon <NUM> to provide a non-occluding medical balloon for drug delivery, in particular for targeted drug delivery to the walls of a blood vessel or body lumen.

As disclosed herein, a non-occluding medical balloon in accordance with aspects of this disclosure can be used for drug delivery using a drug-eluting coating <NUM> applied to some or all of the outer surface <NUM> (e.g., <FIG>) or the outer surface <NUM> of the sidewall <NUM> (e.g., <FIG>). In accordance with a further aspect of the disclosure, a non-occluding medical balloon provides drug delivery by controlled surface emission of a drug or drug-carrying medium. In some embodiments, a non-occluding balloon delivers one or more drugs entirely by controlled surface emission. In other embodiments, the non-occluding balloon delivers one or more drugs by using both drug-eluting coating and controlled surface emission.

Referring now to <FIG>, there is illustrated an exemplary medical balloon <NUM> for drug delivery using controlled surface emission. The balloon <NUM> is substantially similar in many respects to the balloons <NUM> and <NUM> previously described, therefore common reference numbers are used for similar elements. In <FIG>, only a representative portion of the balloon <NUM> is illustrated, the remaining structure having similar features. The sidewall <NUM> of the balloon <NUM> features a plurality of micro-pores <NUM> extending through the outer surface (i.e., outer sidewall) <NUM> of the sidewall <NUM> into the inflation passage <NUM>. The micro-pores <NUM> are holes through the outer surface <NUM> of the sidewall that allow fluid to pass under controlled conditions from the inflation passage <NUM> to the outer surface of the balloon. The dimensions of the micro-pores (denoted by subscript "MP") <NUM>, e.g., a length (LMP) and a diameter (DMP), are selected relative to the surface tension and/or viscosity of the fluid medium <NUM> within the inflation passage <NUM> such that the fluid medium is not released from the micro-pores until a predetermined pressure differential (DPMP) is present between the inflation passage and the exterior of the balloon (e.g., inside the blood vessel). This predetermined release differential DPMP can be selected to allow pressurized inflation medium <NUM> to fully inflate the balloon <NUM> to a pressure below DPMP without significant emission of inflation medium from the micro-pores <NUM>. After inflation of the balloon <NUM>, the pressure of the inflation medium <NUM> can be increased to a pressure above DPMP , at which point the inflation medium will be emitted from the micro-pores <NUM>. The rate of release of the inflation medium <NUM> from the micro-pores <NUM> can be varied by varying the pressure of the inflation medium above DPMP. Release of the inflation medium <NUM> can be stopped by allowing the pressure of the inflation medium to fall below DPMP. By including a drug in the inflation medium <NUM>, the release of the inflation medium <NUM> through the micro-pores <NUM> functions to deliver the drug directly to the surface of the balloon <NUM>.

The micro-pores <NUM> can be formed in the outer sidewall <NUM> using any known method for creating small precision holes in balloon materials. In some embodiments, mechanical or thermal method can be used to form the micro-pores <NUM>. However, for most embodiments, a laser drill or laser ablation apparatus can be used to bore the micro-pores <NUM>. For forming very small micro-pores <NUM>, an excimer or exciplex laser apparatus can be used.

Referring now to <FIG>, there is illustrated one embodiment of an exemplary medical balloon apparatus <NUM> for drug delivery using controlled surface emission. The apparatus <NUM> includes a non-occluding balloon <NUM> operatively connected to a catheter shaft <NUM>. The non-occluding balloon <NUM> has perfusion ports <NUM> disposed at each end and is similar to the non-occluding balloon <NUM> previously described. The balloon <NUM> includes a plurality of micro-pores <NUM> arrayed in multiple longitudinal rows <NUM> disposed on the central portion <NUM>' of the sidewall <NUM>. For purposes of illustration, the micro-pores <NUM> in <FIG> are not shown to scale.

Referring now to <FIG>, there is illustrated another embodiment of an exemplary medical balloon apparatus <NUM> for drug delivery using controlled surface emission. The apparatus <NUM> includes a non-occluding balloon <NUM> operatively connected to a catheter shaft <NUM>. The non-occluding balloon <NUM> has perfusion ports <NUM> disposed at each end and is similar to the non-occluding balloon <NUM> previously described. The balloon <NUM> includes a plurality of micro-pores <NUM> arrayed in ring <NUM> disposed on the central portion <NUM>' of the sidewall <NUM>. For purposes of illustration, the micro-pores <NUM> in <FIG> are not shown to scale. The number and arrangement of the micro-pores can be selected to correspond with desired drug application pattern and/or other drug-deliver requirements.

In other embodiments, a non-occluding balloon having multiple inflation passages <NUM> can be provided, wherein at least some of the inflation passages are on a separate fluid circuits from the remaining inflation passages (i.e., they do not use a common fluid medium source). In such cases, the at least some inflation passages can be used for inflating the balloon, and the remaining (i.e., separate) inflation passages can be used for the delivery of drug-carrying fluid medium through micro-pores. In some such embodiments, only the remaining (i.e., separate) inflation passages can communicate with micro-pores, whereas in other embodiments, both the at least some inflation passages and the remaining inflation passage can communicate with separate sets of micro-pores, thereby allowing for the delivery of more than one drug by a single balloon.

Referring now to <FIG>, there is illustrated a cross-section of a portion of an exemplary balloon outer sidewall <NUM> having thickness TOS (i.e., the outer sidewall is denoted by subscript "OS") containing a single micro-pore <NUM>. In the illustrated embodiments, the micro-pore <NUM> has a constant diameter DMP through the outer sidewall <NUM>, and thus has a length LMP = TOS. If the desired release pressure differential DPMP for the drug-carrying inflation medium can be achieved with micro-pore length LMP = TOS, then a constant diameter micro-pore can used. However, in some embodiments, a full-thickness micro-pore <NUM> does not provide the desired DPMP for the selected drug-carrying inflation medium.

Referring now to <FIG>, there is illustrated a cross-section of a portion of another exemplary balloon outer sidewall <NUM> having thickness TOS containing a single micro-pore <NUM>. In this case, the hole through the outer sidewall <NUM> does not have a constant diameter, but instead has a counter-bore <NUM> of materially greater diameter than the micro-pore <NUM> extending part of the thickness TOS such that the actual micro-pore with diameter DMP has a length LMP that is less than TOS. The counter bore <NUM> has a diameter that is materially greater than the micro-pore <NUM>, meaning that the surface tension/viscosity effects of the drug-carrying fluid medium are negligible in the counter-bore compared to the surface tension/viscosity effects in the micro-pore. The counter bore <NUM> can be created by a first boring operation, and the micro-pore <NUM> can be formed by a second boring operation. By using the counter-bore <NUM> or other variable-geometry hole through the outer sidewall <NUM>, a wide range of release pressure differential pressures DPMP for the drug-carrying fluid medium can be achieved regardless of the nominal thickness of the outer sidewall material.

Referring now to <FIG>, there is illustrated a balloon catheter apparatus <NUM> including a non-occluding balloon for drug delivery in accordance with the disclosure. The balloon catheter apparatus <NUM> includes a catheter hub <NUM>, a strain relief <NUM>, a hypotube <NUM>, a guide wire lumen <NUM>, a section of relatively less flexible tubing <NUM> (e.g., Pebax 72D) overlying a proximal portion of the guide wire lumen, a section of relatively more flexible tubing <NUM> (e.g., Pebax 55D) overlying a distal portion of the guidewire lumen, a multi-lumen non-occluding balloon <NUM> and a nosecone <NUM>. Unless otherwise described, the arrangement and construction of these components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> are generally conventional for medical catheters. Further, the balloon catheter apparatus <NUM> illustrated in <FIG> has a rapid-exchange ("RX") configuration; however other embodiments can have a concentric "over the wire" configuration, a multi-lumen configuration or other known configurations. <FIG> further includes exemplary length station information for the various components; however, these dimensions are not required and can vary in other embodiments. The non-occluding balloon <NUM> of apparatus <NUM> can have any of the previously disclosed configurations and can have a drug-eluting coating <NUM> applied to some or all of the outer surface <NUM> and/or include micro-pores <NUM> for controlled emission of a drug-carrying fluid medium.

Referring now to <FIG>, an enlarged view of the non-occluding medical balloon <NUM> is provided, illustrating the cylindrical central sidewall <NUM>' and the cone-shaped proximal end sidewall <NUM>"(p) and cone-shaped distal end sidewall <NUM>"(d). The balloon <NUM> in <FIG> is semi-transparent, therefore certain internal components are visible. The balloon <NUM> includes perfusion ports <NUM> on each end sidewall <NUM>" and septums <NUM> run between the inflation passages <NUM> from the proximal end to the distal end of the balloon. The balloon <NUM> can be used for drug delivery by using a drug coating <NUM> on the outer surface <NUM> of the balloon and/or by direct emission of a drug-carrying medium from the inflation passages <NUM> through micro-pores in the outer surface of the balloon.

Referring now to <FIG>, there is illustrated a cross-sectional end view taken through section A-A in <FIG>, showing the non-occluding medical balloon <NUM> in the inflated configuration. The sidewall <NUM>, outer surface <NUM>, inflation passages <NUM>, septums <NUM>, perfusion ports <NUM> and guidewire lumen <NUM> are illustrated.

Referring now to <FIG>, additional details of the exemplary balloon catheter apparatus <NUM> are illustrated. <FIG> is a cross-sectional view of the non-occluding balloon <NUM> and adjacent catheter elements. The guide wire lumen <NUM> runs through the central passage <NUM> of the balloon. The sidewalls <NUM> of the balloon <NUM> are supported (when inflated) by pressurized inflation fluid in the inflation passages <NUM> of the cone ends <NUM>" and the central portion <NUM>'.

Referring now to <FIG>, the connection of the exemplary catheter shaft to the balloon <NUM> is illustrated. <FIG> is a cross-sectional end view taken through the catheter shaft along section C-C of <FIG> showing the guidewire lumen <NUM> concentrically disposed within the Pebax sections <NUM> and <NUM>, thereby forming an annular inflation lumen <NUM> therebetween. The rapid exchange (RX) side-entry <NUM> of the guidewire lumen <NUM> can be seen in the background of <FIG> is a cross-sectional end view taken through the unexpanded preform end <NUM> along section B-B of <FIG>. The guidewire lumen <NUM> runs through the central passage <NUM> of the unexpanded end <NUM> with the inflation passages <NUM> disposed in the sidewall <NUM> between septums <NUM>. <FIG> is a cross-sectional side view of the junction between the catheter shaft and the unexpanded end <NUM> of the balloon <NUM>. The junction includes an annular transition space <NUM> which provides fluid communication between the annular inflation lumen <NUM> of the catherter shaft and the multiple inflation passages <NUM> of the balloon end <NUM>. As previously disclosed, the inflation passages <NUM> are in fluid communication with the inflation passages <NUM> of the balloon <NUM>.

Referring now to <FIG>, there is illustrated a cross-sectional side view of the exemplary catheter shaft at a junction area <NUM> between the hypotube <NUM> and the rapid exchange portion having the concentrically-arranged guidewire lumen <NUM> and the outer tubes <NUM> and <NUM>. Within the junction area <NUM>, the inflation lumen <NUM> at the center of the hypotube <NUM> transitions to the annular inflation lumen <NUM> between the inner guidewire lumen <NUM> and outer tubes <NUM> and <NUM>.

Referring now to <FIG>, there is illustrated a schematic diagram of yet another process <NUM> for fabricating a non-occluding medical balloon in accordance with aspects of the invention. At step <NUM>, a balloon preform is provided having a sidewall defining a central passage and having at least one inflation passage disposed in the sidewall. At step <NUM>, the balloon preform is blown into an expanded balloon with the at least one inflation passage in the sidewall. As previously disclosed, blowing the balloon from a preform can include using a mold and pressurizing the central passage of the balloon preform to expand the sidewall against an inner surface of the mold to form the balloon. In some embodiments, the blown balloon includes an expanded center portion that can be of relatively constant diameter, tapered cone portions proximally and distally adjacent to the center portion, and respective proximal and/or distal tail portions (relatively unexpanded from the original preform) adjacent to the smaller end(s) of the cone portion(s). In some embodiments, the step <NUM> can include heating the balloon preform and/or heating the mold. If heating is used, in many embodiments the temperature of the mold and/or preform will be limited to <NUM> degrees C or less. At step <NUM>, at least one end of the expanded balloon is removed to expose (i.e., open) the inflation passage in sidewall of central portion of balloon. In some embodiments, the step <NUM> includes cutting off an entire cone from the center portion of the sidewall, whereas in other embodiments, only a portion of the end cone is removed from the center portion. In some embodiments, the step <NUM> can also comprise cutting off all or part of both end cones from the center portion of the sidewall. In addition to exposing/opening the inflation passage of the sidewall to the exterior of the balloon, the step <NUM> also opens the center passage of the balloon to the exterior of the balloon.

Referring still to <FIG>, at step <NUM> of the process <NUM>, a first end of a preformed inflation lumen is inserted into the inflation passage at edge of sidewall of the central portion of balloon. At step <NUM>, the inner surface of the sidewall of the central portion of balloon is supported and the inner surface of the preformed inflation lumen is supported. In some embodiments, the step <NUM> can comprise supporting the inner surface of the balloon sidewall by inserting a mandrel into the center passage of the balloon. In some embodiments, the step <NUM> can comprise supporting the inner surface of the preformed inflation lumen by inserting a mandrel into the passage of the inflation lumen. In some embodiments, only the edge portion of the inner surface of the balloon sidewall is supported. At step <NUM>, the first end of the preformed lumen is sealed into the inflation passage of the central portion of the balloon and any remaining edges of the inflation passage (i.e., those remaining open to the exterior of the balloon) of the central portion are sealed. In some embodiments, the step <NUM> can comprise melting or fusing the material of the preformed inflation lumen to the material of the balloon inflation passage and melting or fusing the remaining edges of the inflation passage to one another. At step <NUM>, the support is removed from the inner surface of the sidewall and the support is removed from the inner surface of the preformed inflation lumen. In some embodiments, the step <NUM> can comprise removing mandrels from the preformed inflation lumen and/or center passage of the balloon. In step <NUM>, second end of the preformed inflation lumen is sealed to a balloon end connectable to a catheter inflation medium source. In some embodiments, the step <NUM> can comprise connecting the second end of the preformed inflation lumen to an inflation lumen in a separate balloon end. In some embodiments, the step <NUM> can comprise connecting the second end of the preformed inflation lumen to another inflation lumen that is annularly disposed around a guidewire lumen of the balloon.

Referring now to <FIG>, there are illustrated further details of an exemplary non-occluding medical balloon according to the disclosure. Referring first to <FIG>, there is illustrated a perspective view of a balloon preform <NUM> having a sidewall <NUM> with an outer surface <NUM> and an inner surface <NUM> defining a central passage <NUM>. Disposed in the sidewall <NUM> between the inner surface <NUM> and outer surface <NUM> is at least one inflation passage <NUM>. In the illustrated embodiment, the preform <NUM> includes three inflation passages <NUM>. In <FIG>, a portion of the preform <NUM> is shown broken away to illustrate that the central passage <NUM> and inflation passages <NUM> can extend continuously through the balloon preform.

Referring now to <FIG>, the preform <NUM> has been blown/expanded into a balloon body <NUM> including a central portion <NUM>, respective proximal and distal cone portions <NUM> and <NUM>, and respective proximal and distal tail portions <NUM> and <NUM>. The proximal and distal tail portions <NUM> and <NUM> can be substantially unexpanded and thus have the same cross-sectional configuration as the preform <NUM>. In <FIG>, a portion of the expanded central portion <NUM> is shown broken away to illustrate that the central passage <NUM> and inflation passages <NUM> of the preform <NUM> remain extending through the blown/expanded balloon. In other words, the sidewall <NUM> of the balloon body <NUM> can define the same central passage <NUM> and have the same inflation passages <NUM> as the preform <NUM>; however the dimensions (e.g., diameter) of the central passage, the dimensions (e.g., diameter and wall thickness) of the sidewall and the dimensions (e.g., width and height) of the inflation passages can be different from the corresponding structures in the preform due to the stretching of the balloon material that occurs during blowing.

Referring now to <FIG>, at least one of the end cones has been removed from the balloon body <NUM>, thus exposing the edge <NUM> of the sidewall <NUM> and exposing (i.e., opening) the central passage <NUM> and the inflation passages <NUM> to the exterior of the balloon. In the illustrated embodiment, the entire proximal end cone <NUM> (and also the proximal tail <NUM>) is removed. The removal of the cone can be performed by mechanical cutting, laser cutting or any known method for removing material from a medical balloon. In some embodiment, the distal cone <NUM> can be removed instead of the proximal cone <NUM>, and in still other embodiments, both cones can be removed. In some embodiments, only a portion of the end cone or end cones can be removed from the center portion.

Referring now to <FIG>, a first end <NUM> of a preformed inflation lumen <NUM> is inserted into the inflation passage <NUM> from the exposed edge <NUM> of sidewall <NUM> of the balloon body <NUM>. In the illustrated embodiment, the preformed lumens <NUM> have an oval cross section; however in other embodiments, the preformed lumens can have various cross sections including circular, oval, rectangular or other shapes. In the illustrated embodiment, one preformed lumen <NUM> is placed into each inflation passage <NUM>; however in other embodiments, different numbers of preformed lumens can be placed in each inflation passage and the same number of preformed lumens need not be placed in each inflation passage. The preformed inflation lumens <NUM> can be made of the same material as the balloon sidewall <NUM> or of a different material that can be fused or welded to the balloon sidewall.

Referring now to <FIG>, the inner surface <NUM> of the balloon body <NUM> sidewall is supported and the inner surface of the preformed lumens <NUM> are supported. In the illustrated embodiments, the inner surface <NUM> of the sidewall <NUM> is supported by a central mandrel <NUM> (shown in dashed lines) removably inserted into the central passage <NUM> and the inner surface of the preformed lumens <NUM> are supported by lumen mandrels <NUM> (shown in dashed lines) removably inserted into each respective passage of the preformed lumens, e.g., through second ends <NUM>. In other embodiments, support for the inner surface of the sidewall <NUM> and/or the preformed lumens can be provided by other known support structures or support medium. In some embodiments, the inner surface <NUM> of the balloon body <NUM> sidewall and/or the inner surface of the preformed lumens <NUM> are supported when the ends <NUM> of the preformed lumens are placed in the inflation passages <NUM>, and in other embodiments the support is placed after the preformed lumens are inserted into the inflation passages.

While the inner surface <NUM> of the balloon body <NUM> sidewall is supported and the inner surface of the preformed inflation lumens <NUM> are supported, the first end <NUM> of each preformed lumen is sealed into the inflation passage <NUM> of the sidewall <NUM> of the balloon body <NUM> and any remaining edges of the inflation passage (i.e., those edges <NUM> remaining open to the exterior of the balloon) of the central portion are sealed. In some embodiments, the material of the preformed inflation lumen <NUM> can be melted or fused to the material of the balloon sidewall <NUM> surrounding the inflation passage <NUM> and the remaining edges of the inflation passage can be melted or fused to one another.

Referring now to <FIG>, the edge <NUM> of the central portion <NUM> of the balloon body <NUM> is illustrated after the preformed inflation lumens <NUM> have been sealed in the inflation passages <NUM> and the remaining edges of the inflation passages have been sealed to one another. In addition, the support (e.g., mandrels <NUM> and <NUM>) has been removed for the inner surface of the sidewall <NUM> and the inner surface of the preformed inflation lumens <NUM>. In the illustrated embodiment, a seam <NUM> is visible where the sealing has occurred, however, other embodiments can have no visible seam. Each inflation passage <NUM> in the sidewall <NUM> of the balloon body <NUM> can now be in fluid communication with a respective passage through the preformed inflation lumen <NUM> to the respective second end <NUM> of the lumen.

Referring now to <FIG>, there is illustrated a non-occluding medical balloon <NUM> formed from the balloon body <NUM> with attached preformed inflation lumens <NUM> and a guidewire lumen <NUM>. The guidewire lumen <NUM> is disposed through the center passage <NUM> of the balloon body <NUM>. The second ends <NUM> of the preformed inflation lumens <NUM> are formed into a balloon end <NUM> attached to the guidewire lumen <NUM>. In the illustrated embodiment, the second ends <NUM> of the three preformed inflation lumens <NUM> are gathered together and formed into a balloon end <NUM> having an annular configuration with the three inflation lumens (i.e., continuing from inflation passage <NUM>) changing shape (progressive cross-sections are shown in dashed lines) as the preformed inflation lumen transition from discrete tubes into a single annular ring. Perfusion ports or passages <NUM> are formed between the preformed inflation lumens <NUM> since the remainder of the central passage <NUM> remains open at the end <NUM>.

In one embodiment, thermal molding can be used to form the preformed lumens <NUM> into the balloon end <NUM> using mandrels (not shown) within the preformed inflation lumens to position the lumens and maintain the desired interior shape of the inflation passages during thermal molding. In some embodiments, the balloon end <NUM> can have separate inflation lumens <NUM> and in other embodiments, the inflation lumens can be merged to a single annular inflation passage. In some embodiments, the balloon end <NUM> can be formed around the guidewire lumen <NUM>, whereas in other embodiments, the balloon end can be formed separately, e.g., using a mandrel, and attached to the guidewire lumen in a separate operation.

The features disclosed in <FIG> for forming perfusion ports <NUM> at the proximal end of a balloon body <NUM> can be used in substantially identical manner to form perfusion ports at the distal end of the balloon body. The balloon <NUM> can be provided with any of the drug delivery features previously disclosed, including a drug eluting coating <NUM> on the outer surface <NUM> of the balloon body and/or with micro-pores <NUM> formed through the sidewall <NUM> into the inflation passages <NUM>.

Referring now to <FIG>, there is illustrated a non-occluding medical balloon <NUM> in accordance with another aspect of the disclosure having fabricated perfusion ports <NUM> at both the proximal and distal ends of the balloon body <NUM>. The features disclosed in <FIG> for forming perfusion ports <NUM> at the proximal end of a balloon body <NUM> can be used in substantially identical manner to form perfusion ports at the distal end of the balloon body. The balloon <NUM> can be provided with any of the drug delivery features previously disclosed, including a drug eluting coating <NUM> on the outer surface <NUM> of the balloon body and/or with micro-pores <NUM> formed through the sidewall <NUM> into the inflation passages <NUM>.

Referring now to <FIG>, there is illustrated a non-occluding medical balloon <NUM> in accordance with yet another aspect of the disclosure. The balloon <NUM> is substantially similar to balloon <NUM>, except a self-expanding structure <NUM> is provided within the central passage <NUM> of the balloon body <NUM>. The self-expanding structure <NUM> can be a metallic or non-metallic stent or other structure that can selectively transition between a collapsed configuration (as illustrated in <FIG>) and a larger, expanded configuration (illustrated in <FIG>). In some embodiments, the self-expanding structure <NUM> can be disposed inside the central passage <NUM> of the balloon body <NUM> prior to attachment of the preformed inflation lumens <NUM> to the balloon sidewall <NUM>. The self-expanding structure <NUM> can be deployed in accordance with known techniques for deploying stents or other support structures within the body. The self-expanding structure <NUM> can provide additional support for the sidewall <NUM> of the balloon <NUM> to ensure that the outer surface <NUM> contacts the surfaces of the body vessel when inflated.

Claim 1:
A method for fabricating a non-occluding medical balloon for use on a catheter device, the method comprising:
providing a balloon preform (<NUM>) having a sidewall (<NUM>) defining a central passage (<NUM>) and having at least one inflation passage (<NUM>) disposed in the sidewall (<NUM>) between an inner surface (<NUM>) and an outer surface (<NUM>) of the sidewall (<NUM>);
blowing the balloon preform into an expanded balloon (<NUM>) using a blow-molding process; during the blow-molding process, the sidewall (<NUM>) of the balloon preform (<NUM>) reforming into a sidewall (<NUM>) of the expanded balloon (<NUM>), the sidewall (<NUM>) of the expanded balloon (<NUM>) including an inner surface (<NUM>) and on outer surface (<NUM>) which correspond to the respective inner and outer surfaces (<NUM>, <NUM>) of the sidewall (<NUM>) of the balloon preform (<NUM>), an inflation passage (<NUM>) which corresponds to the inflation passage (<NUM>) of the balloon preform (<NUM>), and a central passage (<NUM>) which corresponds to the central passage (<NUM>) of the balloon preform (<NUM>),
supporting the inner surface (<NUM>) of the expanded balloon (<NUM>) with a support (<NUM>);
sealing, at each end of the balloon (<NUM>), the outer surface (<NUM>) and the inner surface (<NUM>) of the sidewall (<NUM>) of the expanded balloon (<NUM>) together across a portion of the inflation passage (<NUM>) of the expanded balloon (<NUM>) and forming a perfusion port (<NUM>) through the sealed portion (<NUM>) of the outer surface (<NUM>) and the inner surface (<NUM>) of the sidewall (<NUM>) of the expanded balloon (<NUM>) into the central passage (<NUM>) of the expanded balloon (<NUM>); and
removing the support (<NUM>) from the inner surface (<NUM>) of the expanded balloon (<NUM>).