HK1081885B

HK1081885B - Stent coating device

Info

Publication number: HK1081885B
Application number: HK06102078.5A
Authority: HK
Inventors: Avraham Shekalim; Ascher Shmulewitz; Eyal Teichman
Original assignee: 拉布寇特有限公司
Priority date: 2002-07-30
Filing date: 2003-07-28
Publication date: 2009-06-19

Description

Stent coating device

This application is a continuation-in-part application of U.S. patent application No.10/136,295 filed on 5/2/2002.

Technical Field

The present invention relates to the art of coating medical devices for implantation into the body, and more particularly to a method and apparatus suitable for use in an operating room for selectively applying a medical coating to an implantable medical device, such as a stent, prior to an implantation procedure.

Term(s) for

The term "prosthesis" refers to any of a number of medical coating devices, including, but not limited to, coronary stents, stent-grafts, Abdominal Aortic Aneurysm (AAA) devices, biliary stents and catheters, TIPS catheters and stents, vena cava filters, vascular filters and peripheral support devices and thrombus filters/retention aids, vascular implants and stents, gastrointestinal tubes/stents, gastrointestinal and vascular anastomosis devices, urinary catheters and stents, surgical and trauma catheters, radiation needles and other indwelling metal implants, bronchial tubes and stents, vascular protection devices, tissue and medical implant heart valves and rings, arterial venous shunts, AV pathway implants, surgical tampons, dental implants, CSF shunts, pacemaker electrodes and leads, suture materials, wound healing, tissue closure devices including wires, staplers, surgical clamps, and the like, IUDs and related pregnancy control devices, ocular implants, timnoplasty implants, hearing aids including cochlear implants, implanted pumps (e.g., insulin pumps), implanted cameras and other diagnostic devices, pharmaceutical packaging, Left Ventricular Assist Devices (LVADs) and other implanted cardiac stents and vascular systems, indwelling vascular catheters and related devices (e.g., pathways), jaw fascia implants, orthopedic implants (joint replacements, trauma and needle surgical devices), cosmetic surgical implant devices, mesh implants (such as for hernia or urethrovaginal repair, encephalopathy, and gastroenteropathy).

The term "drop-on-demand" refers to any active or passive release of a predetermined drop or drops (corresponding to a desired amount) of coating material. Drop-on-demand also refers to the ejection of a series of droplets as they are released. Pressure drop-on-demand technology from san jose ink jet technology, ca, usa is an example of "drop-on-demand" that provides applicators for a wide variety of coating applications. These micromechanical ceramic designs are robust, react little to any fluid with the coating, and can operate in a wide variety of fluids with high PH or strong solubility. non-Newtonian fluids can also be used in these devices because the internal design of the applicator is suitable for laminar flow fluids. Because of the built-in heat generating device and the ability to operate at high temperatures, the pressure drop-on-demand applicator can be used to apply a wide variety of coating materials.

The term "detector" or "detecting" refers to any device or method that utilizes energy, such as magnetic, electrical, thermal, light, etc., to determine whether a target at a desired location on the prosthesis has been located and to signal an applicator to drop on demand or mark that location as a location to be coated. The detector does not determine the position of the applicator relative to the target and provides no feedback for positioning the applicator. The detector determines a point on the coordinate table for a desired location on the prosthesis by providing a signal to the applicator controller that is used immediately or stored as a coordinate table. The detector is a light sensitive device such as a CCD field camera, a CCD line camera, a high resolution CMOS field camera, or a device that can capture light reflected or transmitted through the prosthesis, and an electro-sensitive device such as a capacitive detector.

The term "applicator" or "coating" refers to any configuration, device, or method for positioning coating material onto a surface from a container such as a single point source (including but not limited to a nozzle, dispenser, or tip) or a multi-point source. One example of an applicator is a drop-on-demand ink jet.

The term "on-the-fly" means that the movement and drop-on-demand release are synchronized or nearly synchronized, and/or occur simultaneously or nearly simultaneously. Unlike free-form motion, which requires stopping to confirm anterior-posterior motion relative to the prosthesis, the "fly-by" approach to the next motion does not require a confirmation step. FIG. 13 shows an example of a "co-flying" drop-on-demand application in which the axis of rotation 700 is stationary and the applicator is movable along the Z-axis. The servo controller 705 monitors the speed and position of the applicator 725 through a feedback device 715 to direct the movement of a Z drive 710 coupled to the applicator 725. The servo controller 705 controls the Z drive 710 within the desired speed limits and signals the applicator controller 720 to actuate the drop-on-demand applicator by determining the point to be coated by the detector based on the coordinates from the previous scan using data from the feedback device 715. In this procedure, confirmation of the Z position of the applicator 725 is accomplished in real time by the servo controller 705. The servo controller 705 controls the axis of rotation to determine the next position based on the previous position and the time it takes for the Z drive to move the applicator 725 to the next position. The feedback device 715 provides feedback that is an internal servo-based logic program that is not linked to the actual position relative to the prosthesis and therefore does not become a confirmation step as described above. In an alternative embodiment, the servo controller 705, Z drive 710, Z position feedback device 715, applicator controller 720, and applicator 725 may all be incorporated into an application control module (not shown).

The term "freeform" refers to the movement of the applicator over the prosthetic part to be coated, requiring confirmation by a predetermined user-selected pattern and/or feedback loop of applicator position relative to the prosthetic part to be coated. Validation is done before the coating material is released. In one embodiment, the freestyle motion moves the applicator to a predetermined position according to a user selected pattern. The position of the applicator is verified relative to the prosthesis and a new position is calculated. The applicator is moved to a new, more precise position. The applicator releases the coating material and then moves to the next predetermined location according to the user selected pattern.

It is noted that, in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless expressly and unequivocally limited to one referent. Thus, by way of example, reference to "an applicator" includes two or more applicators, but "n is an integer from 1 to 60" means that n is an integer as it is defined as an integer. It is also noted herein that the term "polymer" is meant to refer to oligomers, homopolymers, and copolymers. The term "therapeutic agent" means a drug, a therapeutic material, a diagnostic material, an inert substance, an active ingredient, and an inactive ingredient.

For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities or percentages or proportions of ingredients of different materials, reaction conditions, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. Without limiting the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, the resulting values may be subject to errors due to inherent imperfections in the measurement tool. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a range of "1 to 10" includes any and all sub-fields between (and including) a minimum value of 1 and a maximum value of 10, i.e., any and all sub-fields having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10, e.g., 5.5 to 10.

Background

It is well known that there is practice to coat implantable medical devices with synthetic or biological active or inactive agents. Various methods have been proposed to apply such coatings. U.S. patent No. 5,922,393 to Jayaraman suggests soaking or dipping the implant device in a bath of liquid drug, U.S. patent No. 6,129,658 to Delfino et al suggests soaking in a stirring bath, U.S. patent No. 5,891,507 to Jayaraman and U.S. patent No. 6,245,4B1 to Alt disclose devices that combine thermal and/or ultrasonic energy with a bath of liquid drug. U.S. Pat. No. 6,214,1B1 to Taylor et al suggests applying the drug through a pressure nozzle.

Initially, such coatings were applied during the manufacturing process. For a number of reasons, such as the short shelf life of certain drugs, coupled with the time interval from production to implantation, and the possibility that medical personnel will determine the particular drug and dosage to be administered to a patient during implantation, it is desirable to have the technology available to apply a coating just prior to implantation. U.S. patent No. 6,309,380 to Larson et al discloses wrapping an implantable device with a drug-containing conformal film, and U.S. patent No. 5,871,436 to Eury, U.S. patent No. 6,6,454 to Berg et al, and U.S. patent No. 6,1171,232BI to Papandrou et al suggest dipping or soaking the implantable device in a bath of drug just prior to implantation. U.S. patent No. 6,3,551 to Wu provides a bathing chamber for use with certain implantable devices, such as stents deployed on balloon catheters (fig. 1).

The various methods and devices described above, which are used just prior to implantation, allow the coating material to adhere to any surface throughout the exposure to the coating environment. This can cause the coating material to adhere to surfaces where a coating is not desired or desired. In addition, the coating may crack or peel off when the implantable device is removed from the implantation device. This occurs with stents deployed on balloon catheters. Because the balloon is inflated, the stent can expand into place, and the coating can crack along the interface between the stent and the balloon. These cracks can cause portions of the coating to peel off of the stent itself. Similar problems can arise when the coating technique does not prevent inadvertent stacking of edges of multiple devices (e.g., struts of a stent), such as along the inner surfaces of the edges. This in turn may affect the efficacy of the coating and adversely affect the overall medical procedure.

It is known to apply a liquid to selected surface locations using ink jet technology. Microfluidics and Biostorage (BioMEMS) SPIC conference at 1 day 10 monthsIn the above published article "application of inkjet printing technology in biological storage and microfluidic systems", authors Patrick Cooley, David Wallace and Bogdan Antohe describe inkjet technology and its range of medically relevant applications in considerable detail: (http:// www.microfab.compapers/papers pdf/spiebiomems 01reprint.pdf)。

U.S. Pat. No. 6,001,311 to Brennan discloses a related device that employs a movable two-dimensional matrix of nozzles to deposit a plurality of different liquid reagents into a receiving chamber. In the Cooley report and the Brennan device, the selective application of the coating material is based on an objective predetermined location of attachment, rather than a "subjective location" as required by the particular coating process. With respect to applying a coating to a medical device with an inkjet applicator, it may only coat selected portions of the device, for example, it may be applied to a stent mounted on a catheter, rather than to the catheter itself. However, such procedures using current technology may require the provision of complex data files, such as CAD images of the instruments to be coated, and the assurance that the instruments are mounted in the coating apparatus in a precise manner, with the precise positioning as in the CAD images.

Other systems using inkjet applicators apply the coating by a "free-form" process. The freeform dots are determined by a preprogrammed user-selected pattern that is unique, much like the vector printing method, depending on the particular shape or contour of the prosthesis type and the desired coating to be achieved. The inkjet nozzle or prosthesis is moved in three dimensions by means of a motion control system. The motion control system enables the ink jet nozzle to be moved to a location of the prosthesis that is ready to be ejected. Alternatively, a camera may be used to acquire real-time images to determine the position of the inkjet nozzle relative to the prosthesis. The inkjet applicator is controlled by activating the spray, moving the inkjet nozzle, and/or moving the prosthesis based on the nozzle position feedback to adjust the pattern to better match the current prosthesis.

This system is particularly inefficient because the preprogrammed user-selected pattern does not accommodate the inherent uncertainty in the surface of the prosthesis. In one non-limiting embodiment, as an example, a stent crimped around a balloon catheter is not crimped to have the same surface every time. This curl cannot be determined at the factory based on the manufacturer's stent specifications. Furthermore, with this type of feedback loop, the spray, the nozzle position, and/or the prosthesis position are controlled solely according to the "first impression", so that a free-form system increases the time for applying the desired coating of the coating. This is undesirable in the operating room, as many coatings (e.g., paclitaxel, rapamycin, or several other pharmaceutical compositions or bioactive agents) must be applied to the stent crimped onto the balloon catheter immediately prior to surgery.

The significance of a prosthesis with drug release is that time and expense can be saved. Studies have shown that the release of a suitable concentration of drug dose on a coronary stent by coating with paclitaxel or rapamycin is useful for preventing restenosis. American Heart Association 2001 annual scientific conference (11.11.14.2001) highlights Kandazari, David E. et al, J.Heart 143(2) USA, 217-228, 2002; drug-eluting stents for the prevention of restenosis: holy cup search, hittt, Bonnie l. et al, catheterization and cardiovascular inventions 55: 409-417, 2002; paclitaxel inhibits cell line proliferation caused by occlusion of the metal scaffold: possible local applications in malignant bile duct obstruction "by Kalinowski, m. et al, examination of radiology 37 (7): 399-. Other studies have shown that the accuracy of the dose is closely related to the cytotoxic properties of the coating drug. Such as: study of taxol cytotoxins in human tumor cell lines, Liebmann, j.e., et al, br.j. cancer, 68 (6): 1104-9, 1993; analysis of paclitaxel exposure time and dose increase in ovarian cancer cell lines, Adler, l.m. et al, cancer, 74 (7): 1891-8, 1994; stent development and local drug delivery, Regar, e, et al, br.med.bulletin, 59: 227-48, 2001. It can also be seenhttp://www.tctmd.com/expert-presentations: comparative pathology of drug eluting stents: insight according to the effectiveness and toxicity of animal experiments, Farb, a. press, CRF drug eluting stent seminar, 2002; experiments on taxol-eluting stents, Grube, E.D., ISET 2002 Miamibeach, 2002, 19-23 months 3-2002 (effect of taxol on stent edges and dose response shielding); sirolimus: latency study-dose, efficacy and toxin assessment, Carter, Andrew j. press, TCT, month 9 2001.

There is therefore a need for an apparatus and method of use thereof that can selectively apply a coating to an implantable medical device just prior to implantation, such that only the device or selected portions thereof can be coated. This is particularly desirable because it allows the user to select the coating material and coating dosage so that the particular coating material and dosage can be selected based on the particular needs of the patient at the time of the implant procedure. In addition, it would be highly desirable if such a device provided a sterile environment in which the application of the coating could be accomplished, and where such a device was suitable for use in an operating room.

Finally, it would be desirable to provide a method and apparatus for coating a prosthesis that reduces coating time by coating the prosthesis "on the fly" without the need to stop the coating at various points.

Disclosure of Invention

The present invention relates to a method and apparatus for selectively applying a medical coating to an implantable medical device, such as a stent, prior to a procedure to be performed, suitable for use in an operating room.

According to the teachings of the present invention there is provided a coating apparatus for selectively applying a coating to a surface of an object, the apparatus applying the coating in dependence on optical properties of the surface so as to apply the coating to a first type of surface and not to a second type of surface, the optical properties of the first type of surface being different from the second type of surface, the coating apparatus comprising: at least one object holding element for holding the object while the coating is applied; at least one optical scanning device configured to scan at least a portion of the object, the optical scanning device being configured to generate an output signal indicative of a surface class of the object; at least one coating applicator configured to attach a fluid to at least a portion of the object; at least one fluid delivery system in fluid communication to supply fluid to the coating applicator; a processing unit at least responsive to the output signal for selectively activating the coating applicator to apply substantially only the coating to the first type of surface; and a drive system configured to cause relative movement between the surface of the object and the coating applicator, and between the surface of the object and the optical scanning device.

According to a further teaching of the present invention, the drive system is configured to rotate the object-holding element about an axis perpendicular to a coating direction of the coating applicator.

According to a further teaching of the present invention, at least one object holding element is used to function when two object holding elements are disposed along two different regions of the object's longitudinal length while supporting the object.

According to a further teaching of the present invention, the two object holding elements are mechanically coupled for synchronous rotation about a single axis perpendicular to a coating direction of the coating applicator.

According to a further teaching of the present invention, the at least one coating applicator includes a pressure pulse actuated drop ejection system having at least one nozzle.

According to a further teaching of the present invention, a spatial relationship between the coating applicator and the object is variable.

According to a further teaching of the present invention, the spatial relationship varies along a first axis and a second axis, the first axis being parallel to a coating direction of the coating applicator and the second axis being perpendicular to a spray direction of the coating applicator.

According to a further teaching of the present invention, the coating applicator is movable relative to the object-holding element, the movement being along the first axis and the second axis to change the spatial relationship.

According to a further teaching of the present invention, the coating applicator and the optical scanning device are both disposed on a movable applicator base movable relative to the object-holding element, the movement being along a first axis and a second axis to change the spatial relationship.

According to a further teaching of the present invention, the at least one coating applicator is implemented as a plurality of coating applicators and the at least one fluid delivery system is implemented as an equal number of fluid delivery systems, each fluid delivery system supplying a different fluid coating material to the coating applicator, each fluid delivery system being in fluid communication with the coating applicator.

According to a further teaching of the present invention, the object is a catheter including a balloon portion, the balloon portion having a stent disposed thereon, such that the stent is a first type of surface and the balloon is a second type of surface.

According to a further teaching of the present invention, the processing unit is responsive to the indication of the relative movement to vary an operating parameter of the coating device as desired.

According to a further teaching of the present invention, the object-holding element, the coating applicator, the optical scanning device, the drive system, and at least a portion of the fluid delivery system are disposed within a housing that includes a coating chamber.

According to a further teaching of the present invention, the housing includes a base housing portion and a removable housing portion.

According to a further teaching of the present invention, the application compartment is defined by portions of both the base housing portion and the detachable housing portion.

According to a further teaching of the present invention, the base housing portion includes the coating applicator, at least a portion of the fluid delivery device, the optical scanning device and the processing unit and at least a first portion of the drive system, and the detachable housing portion includes the object-holding element and at least a second portion of the drive system.

According to a further teaching of the present invention, the base housing portion includes at least one fluid delivery system.

According to a further teaching of the present invention, the detachable housing portion is disposable.

According to a further teaching of the present invention, the coating chamber is a substantially sterile environment.

According to a further teaching of the present invention, the coating applicator and the fluid delivery system are included in a removable sub-housing, the removable sub-housing is disposed within the application chamber, and the removable housing is detachably connected to the processing unit.

According to a further teaching of the present invention, there is also provided a coating apparatus for selectively applying a coating to a surface of an object, the apparatus applying the coating according to an optical property of the surface such that the coating is applied to a first type of surface and not applied to a second type of surface, the first type of surface being optically distinct from the second type of surface, the coating apparatus comprising: a) a housing comprising a coating chamber; b) at least one object-holding element arranged in the coating chamber and configured to hold an object on which a coating is applied; c) a removable applicator station mounted within the coating chamber, the applicator station comprising: i) at least one coating applicator for aligning and depositing a fluid to coat at least a portion of the object; and ii) at least one optical scanning device configured to scan at least a portion of the object, the optical scanning device being configured to generate signals representative of different categories of the surface of the object, displacement of the applicator mount resulting in a change in the spatial relationship between the coating applicator mount and the object; d) at least one fluid delivery system in fluid communication with the coating applicator so that fluid can be supplied thereto; e) a processing unit at least responsive to the output signal for selectively activating the coating applicator to apply substantially only the coating to the first type of surface; and f) a drive system configured to cause relative movement between the surface of the object and the coating applicator base.

According to a further teaching of the present invention, the base housing portion includes the removable applicator base, at least a portion of the fluid delivery system, and the processing unit, and at least a first portion of the drive system, and the detachable housing portion includes the object-holding element and at least a second portion of the drive system.

According to a further teaching of the present invention, at least one fluid delivery system is mounted within the base housing.

According to a further teaching of the present invention, the at least one coating applicator is implemented as a plurality of coating applicators and the at least one fluid delivery system is implemented as a similar plurality of fluid delivery systems, each fluid delivery system supplying a different fluid coating material to the coating applicator, each fluid delivery system being in fluid communication with the coating applicator.

According to a further teaching of the present invention, the coating applicator and the fluid delivery system are included in a removable sub-housing, the removable sub-housing being detachably connected to the removable applicator base.

According to a further teaching of the present invention, the spatial relationship varies along two axes, a first axis parallel to a coating direction of the coating applicator and a second axis perpendicular to the coating direction of the coating applicator.

According to a further teaching of the present invention, the object is a catheter including a balloon portion on which a stent is mounted such that the stent is a first type surface and the balloon is a second type surface.

According to a further teaching of the present invention, there is also provided a coating method for selectively applying a coating to a surface of an object, the method applying the coating according to an optical property of the surface such that the coating is applied to a first type of surface and not applied to a second type of surface, the first type of surface being optically distinguishable from the second type of surface, the coating method comprising: generating relative motion between the object and at least one optical scanning device and at least one coating applicator; optically scanning at least a portion of the object with at least one optical scanning device to produce an output signal representative of different classes of surfaces of the object; the output signal is responded to by selectively activating the coating applicator to apply a coating substantially only to the first type of surface.

According to a further teaching of the present invention, the relative motion includes rotating the object about an axis perpendicular to a coating direction of the coating applicator.

According to a further teaching of the present invention, there is also provided simultaneously supporting the object along two different regions of the length of the object.

According to a further teaching of the present invention, the selectively actuating includes selectively actuating a pressure pulse actuated drop ejection system having at least one nozzle.

According to a further teaching of the present invention, the selectively actuating includes selectively actuating a pressure pulse actuated drop ejection system having at least one nozzle, the pressure pulse actuated drop ejection system included within a movable sub-housing, the movable sub-housing further including a fluid delivery system in fluid communication with the coating applicator to supply the coating material to the coating applicator.

According to a further teaching of the present invention, the applying is performed by selectively activating one of a plurality of coating applicators, wherein at least one coating applicator is implemented as a plurality of coating applicators, each of the plurality of coating applicators applying a different coating.

According to a further teaching of the present invention, the applying is performed by selectively activating a plurality of coating applicators in sequence to apply a plurality of coating layers, each coating layer of the plurality of coating layers having a coating material different from a coating layer of an adjacent layer.

According to a further teaching of the present invention, the response output signal includes an output signal responsive to a balloon portion of the indicator catheter and a stent mounted on the balloon, such that the stent is a first type of surface and the balloon is a second type of surface.

According to a further teaching of the present invention, responding to the output signal includes responding to the output signal being indicative of only the first type of surface such that the coating is applied to substantially an entire surface of the object.

According to a further teaching of the present invention, a varying spatial relationship between the coating applicator and the object is also provided.

According to a further teaching of the present invention, the varying is along two axes, a first axis parallel to a coating direction of the coating applicator and a second axis perpendicular to the coating direction of the coating applicator.

According to a further teaching of the present invention, the varying is accomplished by moving the coating applicator.

According to a further teaching of the present invention, the varying is accomplished by varying a spatial relationship between the object and a movable applicator base on which at least one coating applicator and one optical scanning device are mounted.

According to a further teaching of the present invention, the varying is controlled by a processing unit.

According to a further teaching of the present invention, the operating parameter of the coating apparatus is also changed as desired in response to the indication of the relative motion.

According to a further teaching of the present invention, relative motion is generated, at least a portion of the object is optically scanned, and coating is selectively initiated within the housing.

According to a further teaching of the present invention, coating ejection is provided by a plurality of applicators to achieve better performance.

According to a further teaching of the present invention, a cleaning material container is provided to clean the applicator at the end of the application process. The cleaning material can coexist with the medicine.

According to a further teaching of the present invention, a cover is provided over the front surface of the applicator at the end of use.

According to a further teaching of the present invention, a wiper is provided to clean the applicator surface.

According to a further teaching of the present invention, a meter is provided to measure the amount of coating material applied by the applicator.

According to a further teaching of the present invention, the optical scanning is provided using a light source capable of scanning the saturation of white, black, or other colors.

According to a further teaching of the present invention, features according to the present invention can be used in other coating, dispensing, and attachment methods.

According to a further teaching of the present invention, a method of coating includes (a) providing a prosthesis having identifiable features; (b) pre-scanning the prosthesis prior to coating to identify a profile and to obtain coating coordinates for the profile; and (c) applying the coating material to the desired area of the prosthesis in accordance with the coordinates.

According to a further teaching of the present invention, the method includes (d) determining a path between the coating coordinates for the applicator to deposit the coating material.

According to a further teaching of the present invention, the method includes (e) determining a sequence of coating coordinates.

According to a further teaching of the present invention, the method includes (f) sequentially determining the inter-coating coordinate vectors.

According to a further teaching of the present invention, the method includes (d) determining the predetermined path independent of the coating coordinates.

According to a further teaching of the present invention, the predetermined path covers a surface area of the prosthesis, wherein the surface area includes the coating coordinates.

According to a further teaching of the present invention, the predetermined path is a function of an overall contour and geometry of the prosthesis.

According to a further teaching of the present invention, the method includes (d) post-scanning the prosthesis after coating.

According to a further teaching of the present invention, post-scanning includes rotating the prosthesis and detecting the coated prosthesis.

According to a further teaching of the present invention, the pre-scanning includes rotating the prosthesis and detecting the prosthesis.

According to a further teaching of the present invention, the detecting includes detecting energy from the identifiable features of the prosthesis.

According to a further teaching of the present invention, the pre-scanning includes analyzing the image for edges associated with the prosthesis.

According to a further teaching of the present invention, the pre-scanning includes determining coating coordinates from the edge.

According to a further teaching of the present invention, the detecting includes capturing energy transmitted from around the identifiable features of the prosthesis.

According to a further teaching of the present invention, the coating material is selected from the group consisting of polymers, therapeutic agents, and mixtures thereof.

According to a further teaching of the present invention, the coating method comprises: (a) providing a prosthesis; (b) pre-scanning the prosthesis before coating to obtain coating coordinates of the prosthesis; (c) coating the prosthesis according to the coating coordinates; and (d) post-scanning the prosthesis after coating.

According to a further teaching of the present invention, applying comprises moving the coating applicator and drop-on-demand release of a quantity of coating material from the coating applicator, wherein the moving and the delivering are "in-flight".

According to a further teaching of the present invention, the coating method includes a raster-type coating step.

According to a further teaching of the present invention, the pre-scanning includes rotating the detector and detecting the prosthesis.

According to a further teaching of the present invention, post-scanning includes rotating the detector and detecting the coated prosthesis.

According to a further teaching of the present invention, the detecting includes capturing energy from the prosthesis, or capturing energy transmitted from around the prosthesis.

According to a further teaching of the present invention, the pre-scan and the post-scan comprise analyzing the image for an edge of the prosthesis.

According to a further teaching of the present invention, analyzing includes comparing images from the pre-scan and the post-scan.

According to a further teaching of the present invention, the analyzing includes identifying coating defects.

According to a further teaching of the present invention, the method includes repeating the coating step to recoat the prosthesis at coordinates associated with the detected coating defect.

According to a further teaching of the present invention, the method includes specifying a coating quality for acceptance of the coated prosthesis.

According to a further teaching of the present invention, analyzing includes optically distinguishing the first type of surface from the second type of surface.

According to a further teaching of the present invention, the analyzing includes rendering the three-dimensional shape from the image.

According to a further teaching of the present invention, the analyzing includes identifying a pigment applied to a coating of the prosthesis.

According to a further teaching of the present invention, the spraying includes spraying with hot air, wherein the hot air evaporates the volatile solvent in the coating material.

According to a further teaching of the present invention, the coating includes controlling infrared radiation, wherein the infrared radiation evaporates volatile solvents in the coating material.

According to a further teaching of the present invention, the coating material is selected from the group consisting of a polymer, a therapeutic agent, and mixtures thereof.

According to a further teaching of the present invention, the coating method includes (a) providing a prosthesis having identifiable features; (b) determining a predetermined path independent of the profile; and (c) applying a coating material to a desired region of the prosthesis, wherein the region is a function of the profile.

According to a further teaching of the present invention, the predetermined path covers a surface area of the prosthesis, wherein the surface area includes the desired area.

According to a further teaching of the present invention, the predetermined path is a function of an overall contour or geometry of the prosthesis.

According to a further teaching of the present invention, the coating device includes an applicator for applying the coating material to the prosthesis; a detector for scanning the prosthesis; and an applicator controller connected to the detector and the applicator, wherein the applicator controller is adapted to perform a "fly-by" application.

According to a further teaching of the present invention, the prosthesis includes identifiable features, whereby the detector provides the applicator coordinates to the applicator controller.

According to a further teaching of the present invention, the applicator controller is adapted to determine a path for the applicator between the application coordinates.

According to a further teaching of the present invention, the coating system comprises: (a) means for providing the prosthesis with an identifiable shape; (b) means for pre-scanning the prosthesis prior to coating to identify the profile and to obtain coating coordinates for the profile; and (c) means for applying the coating material to the desired area of the prosthesis in a coordinated manner.

According to a further teaching of the present invention, the system includes (d) means for determining a path for the applicator between the application coordinates.

According to a further teaching of the present invention, the system includes (e) means for determining a sequence of coating coordinates.

According to a further teaching of the present invention, the system includes (f) means for determining the vector between the coating coordinates in a sequence.

According to a further teaching of the present invention, the system includes (d) means for determining the predetermined path independent of the coating coordinates.

According to a further teaching of the present invention, a computer program product for coating, comprising a computer readable medium containing computer readable code, the computer program product comprising the following computer readable program code for implementing actions in a computing platform: (a) program code for providing a prosthesis having a recognizable outline; (b) program code for pre-scanning the prosthesis prior to coating to identify the contour and to obtain coating coordinates for the contour; and (c) program code for attaching a coating material to a desired region of the prosthesis based on the coordinates.

According to a further teaching of the present invention, the computer program includes (d) program code for determining a path for the applicator between the application coordinates.

According to a further teaching of the present invention, the computer program includes (e) program code for determining the order of the coating coordinates.

According to a further teaching of the present invention, the computer program includes (f) program code for sequentially determining vectors between the coating coordinates.

According to a further teaching of the present invention, the computer program product includes (d) program code for determining the predetermined path independent of the coating coordinates.

According to a further teaching of the present invention, the applicator control module includes an applicator adapted to drop a desired amount of coating material at a desired location on the prosthesis; and an applicator controller adapted for "on the fly" application.

According to a further teaching of the present invention, the applicator controller includes a servo controller, a driver for the applicator, and a position feedback device.

Drawings

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is a side view in cross-section of a stent coating device constructed and operative according to the teachings of the present invention.

FIG. 2 is a cut-away perspective view of the stent coating device of FIG. 1.

Figure 3 is a perspective detail of an alternative movable applicator head constructed and operative according to the teachings of the present invention, and herein equipped with a disposable coating applicator.

FIG. 4 is a cut-away perspective view of the stent coating device of FIG. 1 showing the detachable portion of the housing separated from the base portion of the housing.

Figure 5 is a perspective detail of an upper stent holding element constructed and operative according to the teachings of the present invention.

FIG. 6 is a side view of the stent coating device of FIG. 1 showing the entire length of catheter supported by the support antenna.

FIG. 7A is a flow chart of a non-limiting embodiment of a method for coating a stent according to the present invention.

Fig. 7B is a flow chart of a method for coating a stent as is known in the art.

FIG. 8 is a flow chart of a non-limiting embodiment of a pre-coating process according to the present invention.

FIG. 9A is a flow chart of a non-limiting embodiment of a coating process according to the present invention.

Fig. 9B is a flow chart of a process for coating a stent using a preselected library.

Fig. 9C is a flow chart of a process for coating a stent with real-time images.

FIG. 10 is a flow chart of a non-limiting embodiment of a post-coating process according to the present invention.

FIG. 11 shows a detail of a stent on a balloon catheter and shows an enlarged perspective view of the stent surface to be coated.

FIG. 12 shows a flow diagram of a non-limiting embodiment of a raster coating method that does not employ a pre-scan and a post-scan.

FIG. 13 is a flow diagram of an embodiment of moving the applicator and releasing the coating material "in flight". In an alternative embodiment, the servo controller 705, Z drive 710, and Z position feedback device 715 may all be incorporated into the applicator controller 720.

Detailed Description

The present invention is a method and apparatus suitable for use in an operating room to selectively apply a medical coating to an implantable medical device (e.g., a stent) just prior to an implantation procedure.

The principles and operation of a coating apparatus according to the present invention may be better understood with reference to the drawings and the accompanying description.

For purposes of illustration, the embodiments discussed herein are directed to a device for applying a medical coating to a stent disposed on a catheter, the coating being applied just prior to implantation, and if desired, in an operating room. The use of an optical scanning device enables the processing unit to distinguish between the surface area of the stent and the surface area of the catheter. The processing unit selectively activates the coating applicator to apply the coating substantially only on the stent and not on the balloon or other portion of the catheter. The coating applicator discussed herein, by way of non-limiting example, is a pressure pulse actuated drop spray system having at least one nozzle. Drop-on-demand ink jet systems are readily available pressure pulse actuated drop systems and are well suited for use with the present invention. It should be noted, however, that any coating system that can be selectively activated is within the scope of the present invention. While the discussion herein is directed to a specific embodiment for use in an operating room, it may be used elsewhere, this embodiment being a non-limiting example of the application of the principles of the present invention. One of ordinary skill in the art will readily recognize the scope of the coating to which the principles of the present invention are applicable. Even the device described herein, as a non-limiting example, both the modification of the object-holding element and the selection of the liquid coating material are well suited for use with a wide variety of coated objects.

Referring now to the drawings, and as noted above, FIG. 1 shows a device for applying a coating to a stent 2 mounted on a catheter 4. The applied coating may be a synthetic or biological, active or inactive agent. The perspective view of fig. 2 is the same side of the device of fig. 1, and the description of the elements of the device can be better understood with reference to fig. 2, which is described below in conjunction with the accompanying drawings. The catheter 4 is placed in the coating chamber 40 and held by the rotatable catheter holder 6 and the rotatable upper catheter holding element 8, both of which are arranged to be essentially continuously rotatable, i.e. to perform a number of complete 360 degrees of rotation, as required during the coating process. The actual rotation may be completely continuous (without stopping) or intermittent. The upper catheter securement element will be discussed in detail below with respect to fig. 4. The closed coating chamber provides a sterile environment within which the coating process is performed. The rotation of the catheter securement head and the upper catheter securement member is actuated and synchronized by a motor and gear system including gear sets 12, 14, 16 and shaft 18 (see also fig. 2). Alternatively, the gears may be replaced by a belt or chain. As shown in FIG. 6, by way of non-limiting example, the remaining length of the catheter is supported by a support antenna 22. As mentioned above, the object holding element can be modified to hold any object suitable for coating in accordance with the teachings of the present invention.

Drop-on-demand ink jet systems cooperate with associated optical scanning devices and processing units for coating applications. The optical scanning device scans the surface of the object while the object is rotated by the object holding member. The processing unit determines from the output signal from the optical scanning device whether the currently aligned coating applicator surface area is of the type of surface to be coated. When it is determined that the desired type of surface is aligned with the coating applicator, the processing unit activates the coating applicator to apply. The embodiment shown here includes three inkjet coating applicators 30a, 30b, and 30c, and two optical scanning devices 32a and 32 b. The optical scanning device may be arranged to generate a digital output signal or an analog signal, which is then analyzed by the processing unit. It should be noted that the number of coating applicators and scanning devices can be modified to meet design or application requirements. The three coating applicators and the two optical scanning devices are mounted on a movable applicator head 34. The coating control module 36, which in turn is controlled by the processing unit, adjusts the position of the applicator head within the coating chamber and thereby adjusts the spatial relationship between the coating applicator and the stent or other object being coated. The change in applicator head position in the vertical direction is accomplished by rotating vertical positioning screw 60 in conjunction with guide rod 62 and the change in the horizontal direction is accomplished by rotating horizontal positioning screw 64 in conjunction with guide rod 66. The vertical positional variation of the object, in combination with the rotation of the object, enables the coating applicator to span substantially the entire surface of the object to be coated.

The fluid coating material is stored in three fluid containers 50a, 50b, and 50c (see FIG. 2) and is supplied to the corresponding coating applicators by fluid supply hoses 52a, 52b, and 52c (see FIG. 2). In general, each fluid container contains a different coating material, and thus, each coating applicator desirably attaches a different coating material to the stent or other object being coated. Also, multiple coatings may be applied, each with a different coating material and, if desired, with a different thickness. Thus, during coating, a single suitable coating material may be selected from the materials provided, or a combination of coating materials may be selected. It should be noted that although the fluid container is shown here as being located within a chamber of the device housing, this is not always required and the container may also be external to the housing.

It should be noted that the ink jet system may alternatively be provided in a disposable housing which also includes a fluid reservoir filled with the coating material. The fluid container may be an enclosed volume portion integrated with the disposable housing or a cartridge filled with coating material that is built into a receiving chamber of the disposable housing. In this case, as shown in FIG. 3, the movable applicator head 34 may be configured to accept one or more disposable housings 36a, 36b, and 36c, which in turn house inkjet coating applicators 38a, 38b, and 38 e. The fluid reservoir (not shown) for each applicator is placed in a partial space of a disposable housing disposed within the movable applicator head 34.

Fig. 4 shows how the base housing portion 70 and the removable housing portion 72 are connected. The two parts are held together by latches 74 which extend from the detachable housing part, are inserted into corresponding pin holes 76 in the base housing part and engage a latch mechanism 78 with catch elements 80. The two housing portions can be disengaged by depressing a release "button" 84 which raises the latch end 82, thereby releasing the latching element. The two parts can then be pulled apart. As can be seen more clearly here, the application chamber is defined by a top, a bottom and three walls in the detachable housing part and a wall on the basic housing part. The removable housing portion is configured to be disposable or designed to be easily cleaned and resterilized as desired.

The detail shown in figure 5 illustrates the construction of the upper catheter securement element. A threaded tube 92 extends from a substantially central location of the rotating base plate 90. The tube is the outer end of a channel through which the end of the catheter to which the stent is attached can be inserted to place the stent in the coating chamber of the coating apparatus. The tube is cut several times longitudinally to create threaded portions 98, here six threaded portions 98, so that the arrangement is such that it flexes from the center outwards. The holding plate 94 has a correspondingly threaded central hole for mating with the threaded tube 92 so that when the holding plate is brought into position adjacent the chassis, the threaded portion near the end of the tube will flex outwardly, thereby enlarging the diameter of the opening. The gripping element 96 also has bifurcated flexible "jaws" 100. In operation, the clamping element is placed around the conduit, and the conduit is then passed through the threaded tube and into the coating chamber. Once the conduit is positioned on the conduit mount, the clamping element is at least partially inserted into the opening of the threaded pipe. The anchor plate 94 is then rotated about the threaded pipe to a position proximate the end of the threaded pipe, and the outwardly flexible portion 98 of the threaded pipe enters a non-deflected state, thereby reducing the diameter of the opening. The reduction in the diameter of the threaded tube opening pushes the "jaws" of the clamping member against the catheter, thereby securing the catheter in place.

A non-limiting example of a stent coating method implemented by the above apparatus is implemented as follows:

1. the fluid container is filled with the desired fluid coating material.

2. The coating parameters are input into the processing unit. According to non-limiting examples, the parameters may include the coating material to be applied, the thickness of the coating, the number of layers of different coating materials, the order of the materials of the stack to be applied, and the thickness of each layer. The parameters may be determined by the physician at the time of application of the coating, or the parameters may be preset, such as those that may be determined according to medical rules. In the case of preset parameters, the physician simply enters a "start" command.

3. The catheter is placed in the coating chamber and the upper catheter securement element is secured.

4. As the catheter rotates, the optical scanning device scans the surface of the catheter to distinguish the surface of the balloon from the surface of the stent.

5. When a portion of the surface of the stent is detected and determined to be aligned with the appropriate coating applicator, the processing unit selectively activates the applicator to spray the necessary amount of coating material to adhere substantially only to the surface of the stent.

6. The position of the applicator head is adjusted as necessary throughout the coating process. The adjustment can bring the coating applicator closer to or further away from the surface of the stent and can adjust the vertical placement of the coating applicator, allowing different regions of the stent surface to be coated. In addition, if different fluid coating materials are required for different layers of the coating, the coating applicator that applies that particular coating material can be properly aligned to adhere the new coating material to the stent.

7. When the coating process is complete, the catheter with the coated stent is removed from the device and the stent is ready for implantation.

8. The removable housing portion is removed, cleaned and sterilized for reuse or for disposal at a glance.

It should be noted that in some cases it may be desirable to completely coat the entire surface of the object being coated. There are at least two ways in which this can be achieved. The object itself may have only one surface. Alternatively, the scanning device may be arranged to provide an adjustable scanning sensitivity. In this case, the sensitivity of the scanning device may be adjusted such that the output signal indicates only one kind of surface and the processing unit cannot distinguish between different kinds of surfaces.

The flow chart in FIG. 7A illustrates a method of coating a prosthesis 102 according to the present invention. In this non-limiting example, the prosthesis is a stent that is ready to be coated with a therapeutic agent. The first step 105 is to place the stent and therapeutic agent container into the stent coating device. The system is then ready to coat the stent. At step 110, the system starts. The pre-coating process 115 collects information from the processing units of the stent coating device for use in the coating process 120. The post-coating process 125 verifies that the stent has been properly coated and, at step 130, is acceptable and can be removed.

The flow chart of fig. 7B illustrates a method 140 for coating a stent as is known in the art. The user selects the pattern 145 depending on the type of stent to be coated and the form of coating to be released. The pattern selected will vary depending on the parameters provided by the stent manufacturer and the coating to be applied. The program 150 is initiated according to the selected pattern. The coating process 155 applies a coating to the stent and once completed, the coated stent 160 may be removed.

Fig. 8 illustrates a pre-scan process 115. The stent is pre-scanned 205 prior to the coating process 120. In parallel, the coating control module is initialized 200. Initialization of the coating control module includes finding a specific point on the stent at which coating begins. The pre-scan is analyzed 210 in the processing unit. This analysis is used to determine and compile a coating coordinate table 215 for use in locating coating control modules.

There is a large standard deviation between stents of the same design, particularly after crimping the stent onto the balloon catheter. Pre-programmed patterns do not help to account for these errors from the design. Pre-scanning may provide for detection of defects in the stent structure prior to coating. The pre-scan may also provide an optimal location to apply the coating to that location. Crimping does not always result in uniform deformation of the scaffold structure. Some portions of the stent may be crimped to a greater degree than other portions. Some intersections of stent struts may have different angles of inclination. The pre-scan may provide an optimal path to cover the surface of the stent to be coated. Some coatings require coating onto only a portion of the stent to be coated. The pre-scan may prevent the coating at a specific location from being oversprayed. Excessive spraying can result in undesirable coatings on the stent of the balloon catheter.

Scanning may be accomplished by a variety of imaging techniques known in the imaging arts, including but not limited to photographic, video, infrared, and VCSEL (vertical cavity surface emitting laser) techniques, as well as a variety of detectors. VCSEL lasers can be used as optical image detectors and can double as coaters themselves. See Choquette, Kent D, MRS Bulletin, pp.507-511, 2002, 7 months. In one non-limiting embodiment, the stent is photographed using a detector. The stent is rotated slightly (e.g., half to a few degrees) and then another picture is taken, for a total of at least tens of pictures. The detector is focused sufficiently close to the stent so that sufficient resolution can be recorded relative to the coating droplets to be applied. If the stent is long, it may be necessary to repeat the rotation to take pictures of the top and bottom of the stent.

The light source may be placed on the same side of the detector, or on the other side of the detector relative to the support. In this embodiment, the light source is on the same side of the detector, which receives light reflected from the support. The stent appears bright and the balloon appears dark. In embodiments where the light source is located on the other side of the detector, the detector receives light transmitted through the balloon and around the stent struts. The stent appears dark and the balloon appears light. The contrast of light colors to dark colors in both embodiments can be used for edge analysis. Edge analysis involves determining the edges of the stent and finding the centerline of the stent surface to be coated. The edges and the centre line define coating coordinates, which are collected in a coating coordinate table for each surface of the stent to be coated.

In one non-limiting embodiment, the pre-scan process is compared to the pattern index in the processing unit. This can be used to determine the accuracy of the edge analysis and provide a safeguard for detecting defects in the stent or errors in the edge analysis.

The overlay coordinates may be interpreted and encoded into a raster or vector type data format. These data formats describe the different displacements of the applicator performed by the Z drive. Both data formats involve the use of algorithms to find all the coordinates of the stent that should be coated and to map the "points to be coated" or coordinates. Graph 1 is a graph showing the position of a point in the Z direction as a function of rotation angle relative to the axis.

Vector-like coating involves taking unique variables (e.g., Z and rotation), selecting the shortest distance with another algorithm, or selecting the most efficient path, moving from one coating coordinate to the next nearest neighbor coordinate to be coated. The vector overlay may also include generating an ordered coordinate column. Table 1 shows a "best path algorithm" as a coordinate table that relates the position in the Z direction to the rotation angle for each coordinate.

TABLE 1

Coordinate serial number	Z	Rotation angle
Coordinate serial number	Z	Rotation angle	1	3	15

2	6	30
2	6	30	3	9	45
4	6	60	3	9	45
4	6	60	5	9	60
6	15	60	5	9	60

The control software in the processing unit may calculate a set of motion vectors between each set of sequential coordinates for the coating control module. The vector parameters may include coordinates, Δ Z (position change between two adjacent points or coordinates on the Z-axis), Δ rot (angle change between coordinates), speed between coordinates, and the like. Table 2 shows vectors that can be calculated from the coordinate table of table 1. Each vector may have a different velocity associated with it, represented by the values a, b and c, respectively. Each vector may have a different size associated with it, denoted d, e, f, g, h, which may be the same or different. Other parameters may also be associated with each vector.

TABLE 2

Vector	ΔZ	Δrot	Speed of rotation	Number of
Vector	ΔZ	Δrot	Speed of rotation	Number of	1-2	3	15	a	d
2-3	3	15	a	e	1-2	3	15	a	d
2-3	3	15	a	e	3-4	-3	15	a	f
4-5	3	0	b	g	3-4	-3	15	a	f
4-5	3	0	b	g	5-6	6	0	c	h

Raster-type coating involves finding all coordinates of the stent that should be coated with an algorithm and compiling a coordinate map. This is similar to the vector type coating shown in table 1 above. However, raster-like coating also involves taking unique variables (e.g., Z and rotation) and using different algorithms to calculate and compile a coordinate table of Z coordinates for each rotation angle rotated in predetermined increments. The term "rotation resolution" refers to an incremental value of the rotation angle. Raster-like coating is "specific rotational resolution". This means that raster printing can be calculated and performed with a specific rotational resolution or in a number of other ways in connection with the prosthesis to be coated, the prosthesis fixture and the applicator, the fixture and applicator nozzle for the prosthesis, etc. Table 3 shows a coordinate table relating rotation angle to Z-position. These positions are: z1, Z2, Z3, Z4, etc., indicating the intersection of the stent surface to be coated at each rotation angle.

TABLE 3

Rotation angle	Z1	Z2	Z3	Z4
Rotation angle	Z1	Z2	Z3	Z4	15	3	9
30	6	20			15	3	9
30	6	20			45	9
60	6	6	15		45	9

Control software in the processing unit can calculate the Z coordinate for each angular position and control the coating control module and coating applicator to turn to an angular rotational position and move along Z at regular, constant or variable speeds. The coating applicator sprays at Z1, Z2, Z3, Z4, etc. coordinate positions while moving along Z. After the full length of the stent has been advanced along the Z-line, the coating control module moves the coating applicator to the next rotational angle, changing the direction in which the coating applicator is advanced along the Z-line (now the opposite direction to the previous direction). The coating applicator sprays at the next Z position while traveling in this new direction.

Other grating-based operations include, for example, rotational movement of the stent in combination with continuous, stepped Z-axis movement, or "helical" movement along a helical path of the stent by causing both rotational and stepped Z-axis movement to occur simultaneously, as described below. In any event, the raster-based coating method results in movement of the stent and applicator to cover the entire prosthesis, whereas the vector-based coating method only travels across the "to-be-coated" surface. Thus, the vector-based path depends on the object, whereas the grating-based path is only defined by the system.

Fig. 11 shows the stent 2 on the balloon catheter 4. The axis of rotation Z is also the axis of symmetry 500 of the stent. The enlarged window of fig. 11 shows the stent structure 505 to be coated and the gaps in the stent structure where the balloon catheter 4 is not covered by the stent. During scanning, the gantry is rotated at increasing angles according to the angular resolution to produce a coordinate table. During the coating process, the coating control module rotates the stent at the same incremental angle and positions the coating applicator in the Z position to coat the stent. In one non-limiting embodiment, the coating applicator can drop-on-demand with a precision that is well known in the art of inkjet printing.

The flow chart of fig. 9A illustrates one embodiment of a coating process 120. This embodiment contemplates that the raster coating is accomplished by longitudinal movement of the applicator along the length of the cylinder, and point-to-point ("PTP") rotation of the cylinder or rotation of the applicator around the circumference of the cylinder. Step 300, selecting an initial angle of rotation. At step 310, the coating control module moves the coating along the Z axis while controlling drop-on-demand at the Z coordinate and receives the next coating coordinate from the processing unit. Once the coating applicator has moved along the length of the stent, the coating control module changes the direction of travel of the coating applicator along the Z-axis and rotates the stent to the next rotational angle, step 325. The process is repeated by repeating step 310 and step 325 until the stent has been coated according to the coordinate system. In one non-limiting embodiment, the change in rotational increment angle can be one-half of 1 degree and requires that the shaft 500 of the stent be rotated until every point in the coordinate table can be coated. Multiple coatings may be applied sequentially or simultaneously by repeating these steps and/or changing the coating vessel.

In another embodiment, raster coating can be achieved by coating along the circumference of the cylinder or by rotation of the applicator along the cylinder with longitudinal movement of the applicator along the PTP of the cylinder length. In another embodiment, the grating coating is accomplished by a circumferential rotation of the cylinder or applicator, and a longitudinal movement of the applicator, accompanied by a PTP longitudinal movement of the applicator, or a PTP rotation of the cylinder or applicator in the cylinder circumference. This embodiment forms a spiral or "helical" predetermined path.

In another embodiment, raster coating is achieved by following a predetermined path to apply the coating material to the desired location of the prosthesis regardless of the coating pattern. In some embodiments, the predetermined path may incorporate the overall contour or geometry of the prosthesis to effectively cover the surface area including the desired location to be coated. In certain embodiments, efficiency may be achieved by utilizing an axis of symmetry or other simplified geometry of the overall profile of the prosthesis.

The flow chart of fig. 9B illustrates a coating process 155 as is known in the art. The coating nozzle is brought to an initial position, step 330. In step 335, the controller receives coordinates from the user selected pattern. In step 340, the controller resolves the coordinates into constant X, Y, and Z motions and positions the nozzles for jetting by controlling nozzle delivery (step 350), controlling nozzle motion (step 355), and/or controlling gantry operation (step 360). Then, at step 365, the nozzles spray drops as needed. The nozzle then travels along the stent to the next coordinate according to the user selected pattern.

The flow chart of fig. 9C illustrates a coating process 155 as known in the art, again beginning with the coating nozzle in an initial position, step 330. In step 342, a picture of the nozzle, stent, and/or coating is taken. At step 345, the picture is analyzed with imaging software. The controller interprets the picture and positions the nozzles for firing by controlling nozzle delivery (step 350), nozzle movement (step 355), and/or carriage movement (step 360). Then, at step 365, the nozzle sprays drops 365 as needed. This requires real-time imaging and adjustment before coating portions of the stent.

The flow chart of fig. 10 illustrates one embodiment of the present invention, including a post-coating process 125. The coating applicator is controlled to be in a waiting mode 400 while the stent is post-scanned 405 and the coated stent is analyzed for coating defects by a scan analysis step 410 to provide coating quality assurance and acceptance (step 420). And step 130, if the stent is qualified, ending the stent coating process. In one non-limiting embodiment, the coating includes a pigment to aid in scanning analysis by distinguishing the stent from the coating. In one non-limiting embodiment, the pre-scan image can be used for acceptance of the stent. Post-scanning helps locate coordinates where the coating is not being applied due to jetting problems. Post-scanning also helps to locate the leak or "overspray" point at which the coating leaks from the stent onto the balloon catheter.

The flow chart of fig. 12 shows an embodiment of raster coating without a pre-scan and a post-scan. The method 600 for coating a prosthesis begins with step 605 setting a predetermined length L, a linear motion increment Δ x, and an angular motion increment Δ θ along a reference point representing a topographical feature of the prosthesis. At step 610, the detector is turned on. At step 615, the detector and applicator are moved linearly from the reference point along the length L by incremental distances Δ x and Δ θ. At step 620, the detector looks for a desired target of the area to be coated on the prosthesis. If the detector finds the target, the applicator drops on demand (step 625). If the detector does not find the target, or after the applicator dispenses drops as needed (step 625), the detector and applicator are moved by Δ x (step 630). The detector determines whether it has traveled the full length L of the prosthesis by detecting whether the total amount of Δ x movement is greater than or equal to L (Σ Δ x ≧ L) (step 635). If the detector has not traveled the full length L, the detector and applicator are moved Δ x (step 640) and the target is located (step 620), and if the detector has traveled the full length L, the detector and applicator are shifted by Δ θ (step 645). The detector determines whether it has completed around the entire contour of the prosthesis by detecting whether delta theta has moved a total amount greater than or equal to 360 degrees (sigma delta theta > 360 deg.) (step 650). If the detector has not traveled 360 degrees, the detector and applicator are moved linearly along the length L by incremental distances Δ x and Δ θ (step 615). If the detector has traveled 360 degrees, the coating is finished (step 655).

The present invention teaches a method of coating a prosthesis as well as an apparatus for coating a prosthesis, a system for coating a prosthesis, and a coating control module for coating a prosthesis.

It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the spirit and scope of the present invention.

Claims

1. A method for applying a coating material, the method comprising:

(a) providing a prosthesis having a recognizable outline pattern;

(b) -pre-scanning the entire surface area of the prosthesis sufficiently before applying the coating material to identify the identifiable features and to obtain coating coordinates of the identified features; and

(c) applying the coating material to the surface of the prosthesis at approximately each of the application coordinates by moving a coating material applicator relative to the prosthesis, wherein movement of the coating material applicator relative to the prosthesis does not substantially follow any portion of the identifiable topographical pattern.

2. The method of claim 1, wherein the movement of the coating material applicator relative to the prosthesis is one of:

a generally helical path around the prosthesis; and

running a substantially linear path substantially parallel to the longitudinal axis of the prosthesis.

3. The method of claim 1, further comprising:

(d) determining an order of the coating coordinates.

4. The method of claim 1, further comprising:

(d) after applying the coating material, the prosthesis is post-scanned.

5. The method of claim 4, wherein the post-scanning comprises rotating the prosthesis and detecting the coated prosthesis.

6. The method of claim 1, wherein the pre-scanning comprises rotating the prosthesis and detecting the prosthesis.

7. The method of claim 6, wherein the detecting comprises detecting energy from identifiable features of the prosthesis.

8. The method of claim 7, wherein the pre-scanning further comprises analyzing the image to identify edges associated with the prosthesis.

9. The method of claim 8, wherein the pre-scanning further comprises determining the coating coordinates from the identified edges.

10. The method of claim 6, wherein said detecting comprises optically separating the first type of surface from the second type of surface.

11. The method of claim 10, wherein the detecting further comprises providing a three-dimensional shape from the image.

12. The method of claim 6, wherein the detecting comprises identifying pigments in the coating material applied to the prosthesis.

13. The method of claim 1, wherein the movement of the coating material applicator relative to the prosthesis is a generally linear path that runs generally parallel to a longitudinal axis of the prosthesis, the method further comprising:

moving the coating material applicator from a first end of the prosthesis to a second end of the prosthesis across a surface region of the prosthesis; and

applying the coating material to the surface of the prosthesis at approximately each point on the path corresponding to an application coordinate.

14. A method of applying a coating material to a prosthesis having a recognizable topographical pattern, the method comprising:

scanning the identifiable topographical pattern to identify a plurality of coating locations at which the coating material is applied to the prosthesis prior to applying the coating material;

calculating a plurality of coating coordinates according to the identified plurality of coating positions; and

moving a coating material applicator and the prosthesis relative to each other to define a motion path of the coating material applicator relative to the prosthesis, and causing the coating material applicator to apply the coating material to the surface of the prosthesis at approximately each point on the motion path corresponding to one coating coordinate.

Wherein the motion path does not substantially follow the recognizable outline pattern.

15. The method of claim 14, wherein the path of motion is not substantially along any portion of the recognizable outline pattern.

16. The method of claim 14, wherein the motion path is a substantially linear path that runs substantially parallel to a longitudinal axis of the prosthesis.

17. The method of claim 16, wherein the motion path is defined by:

moving a coating material applicator along a generally linear path that runs generally parallel to a longitudinal axis of the prosthesis; and

rotating the prosthesis about its longitudinal axis while moving the coating material applicator,

wherein the motion path describes a helical path around the prosthesis.

18. The method of claim 14, further comprising:

rotating the prosthesis about its longitudinal axis to a first angular position corresponding to the coating material applicator; and

moving the coating material applicator along a generally linear path that runs generally parallel to a longitudinal axis of the prosthesis when the prosthesis is at rest in a first angular position,

wherein the motion path describes a raster motion around the prosthesis.

19. The method of claim 14, wherein scanning comprises:

generating an image of the recognizable outline pattern; and

processing the generated image.

20. The method of claim 19, wherein the calculating comprises: the angular and linear positioning position of the rotating member is determined for each coating coordinate.

21. The method of claim 14, wherein the motion path is defined by:

moving a coating material applicator to a first point along a longitudinal length of the prosthesis; and

rotating the prosthesis about its longitudinal axis while the coating material applicator is stationary at the first point,

wherein the motion path describes a loop around the prosthesis.

22. The method of claim 21, further comprising:

moving the coating material applicator to a second point along the longitudinal length of the prosthesis; and

rotating the prosthesis about its longitudinal axis while the coating material applicator is stationary at the second point,

wherein the motion path describes a plurality of linearly diverging rings around the prosthesis.

23. An applicator device for applying a coating material to a prosthesis having a recognizable topographical pattern, comprising:

means for scanning said identifiable topographical pattern and identifying a plurality of coating locations prior to applying said coating material, applying said coating material to a prosthesis at said coating locations;

means for calculating a plurality of coating coordinates from said identified plurality of coating locations; and

means for moving the coating material applicator and the prosthesis relative to one another to define a path of motion of the coating material applicator relative to the prosthesis and for causing the coating material applicator to apply the coating material to the surface of the prosthesis at substantially each point on the path of motion corresponding to one of the coating coordinates, wherein the path of motion does not substantially follow the identifiable topographical pattern.

24. The coating apparatus of claim 23, wherein the path of motion is not substantially along any portion of the identifiable topography pattern.

25. The coating apparatus of claim 23, wherein the motion path is a substantially linear path that runs substantially parallel to a longitudinal axis of the prosthesis.

26. The coating apparatus of claim 23, further comprising:

means for moving the coating material applicator along a generally linear path that runs generally parallel to a longitudinal axis of the prosthesis; and

means for rotating the prosthesis about its longitudinal axis while moving the coating material applicator,

wherein the motion path describes a helical path around the prosthesis.

27. The coating apparatus of claim 23, further comprising:

means for rotating the prosthesis about its longitudinal axis to a first angular position corresponding to the coating material applicator; and

for causing the coating material applicator to move in a direction generally parallel to a longitudinal axis of the prosthesis when the prosthesis is at rest in the first angular position

A device for moving in a linear path, comprising,

wherein the motion path describes a raster motion around the prosthesis.

28. The coating apparatus of claim 23, wherein the scanning apparatus comprises:

means for generating an image of the recognizable outline pattern; and

means for processing the generated image.

29. The coating apparatus of claim 23, wherein the computing device comprises:

means for determining the angular and linear positioning position of the rotating member for each coating coordinate.

30. The coating apparatus of claim 23, further comprising:

means for moving the coating material applicator to a first point along a longitudinal length of the prosthesis; and

means for rotating the prosthesis about its longitudinal axis while the coating material applicator is stationary at a first point,

wherein the motion path describes a loop around the prosthesis.

31. The coating apparatus of claim 30, further comprising:

means for moving the coating material applicator to a second point along the longitudinal length of the prosthesis; and

means for rotating the prosthesis about its longitudinal axis when the coating material applicator is stationary at the second point,