(12) United States Patent
`Flower et al.
`
`US006351663B1
`(io) Patent No.:
`US 6,351,663 B1
`(45) Date of Patent:
`Feb. 26,2002
`
`(54) METHODS FOR DIAGNOSING AND
`TREATING CONDITIONS ASSOCIATED
`WITH ABNORMAL VASCULATURE USING
`FLUORESCENT DYE ANGIOGRAPHY AND
`DYE-ENHANCED PHOTOCOAGULATION
`
`(75) Inventors: Robert W. Flower, Hunt Valley, MD
`(US); Abu Alam, Lake Forest, IL (US)
`
`(73) Assignee: Akorn, Inc., Buffalo Grove, IL (US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/393,456
`(22) Filed:
`Sep. 10, 1999
`
`Int. Cl.7.................................................... A61B 6/00
`(51)
`(52) U.S. Cl........................ 600/476; 600/431; 250/459.1
`(58) Field of Search .................................. 600/431, 473,
`600/476, 160, 182; 606/4, 10, 13, 15; 604/19;
`382/130; 250/459.1
`
`(56)
`
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`OTHER PUBLICATIONS
`“Photosensitizer,” Ophthamalmic Surgeiy and Lasers, vol.
`28, No. 5, p 410 (1997).
`Desmettre et al., “Diode Laser-Induced Thermal Damage
`Evaluation on the Retina with a Liposome Dye System,”
`Lasers in Surgery> and Medicine, vol. 24, pp. 61-68 (1999).
`Flower et al., “Evolution of Indocyanine Green Dye Chor­
`oidal Angiography,” Optical Engineering, vol. 34, No. 3, pp.
`727-736 (1995).
`(List continued on next page.)
`
`DE
`DE
`EP
`EP
`EP
`EP
`EP
`GB
`GB
`GB
`JP
`WO
`WO
`wo
`wo
`wo
`wo
`
`Primary Examiner—Marvin M. Lateef
`Assistant Examiner—Shawna J Shaw
`(74) Attorney, Agent, or Firm—Leydig, Voit & Mayer, Ltd.
`(57)
`ABSTRACT
`Methods concerning medical uses for fluorescent dyes, e.g.,
`Indocyanine green (ICG), fluorescein, rose bengal, for diag­
`nosis and treatment. Methods for enhancing the clarity of
`fluorescent dye angiograms using relatively high dye
`concentrations, methods for determining the direction of
`blood flow within a blood vessel using fluorescent dye
`angiograms, and methods of identifying blood vessels that
`feed a lesion, such as a CNV or tumor. Methods of reducing
`the flow of blood into lesions incorporating dye-enhanced
`photocoagulation are also provided.
`
`83 Claims, No Drawings
`
` VISIONSENSE - 1003
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`

`US 6,351,663 B1
`Page 2
`
`OTHER PUBLICATIONS
`Flower et al., “Pulsatile Flow in the Choroidal Circulation:
`A Preliminary Investigation/’ EYE, vol. 4, pp. 310-318
`(1990).
`Flower et al., “Variability in Choriocapillaris Blood Flow
`Distribution,” Investigative Ophthalmology & Visual Sci­
`ence, vol. 36, No. 7, pp. 1247-1258 (1995).
`Flower, “Choroidal Angiography Today and Tomorrow,”
`Retina, vol. 12, No. 3, pp. 189-190 (1992).
`Flower, “Extraction of Choriocapillaris Hemodynamic Data
`from ICG Fluorescence Angiograms,” Investigative Oph­
`thalmology & Visual Science, vol. 34, No. 9, pp. 2720-2729
`(1993).
`Flower, “Injection Technique for Indocyanine Green and
`Sodium Fluorescein Dye Angiography of the Eye,” Inves­
`tigative Ophthalmology, vol. 12, No. 12, pp. 881-895
`(1973).
`Gathje et al., “Stability Studies on Indocyanine Green Dye,”
`Journal of Applied Physiology, vol. 29, No. 21, pp. 181-185
`(1970).
`Holzer et al., “Photostability and Thermal Stability of
`Indocyanine Green,” J, Photochem. Photobiol. B: Biol, vol.
`47, pp. 155-164 (1998).
`Klein et al., “An Image Processing Approach to Character­
`izing Choroidal Blood Flow,” Investigative Ophthalmology
`& Visual Science, vol. 31, No. 4, pp. 629-637 (1990).
`Mild et al., “Computer Assisted Image Analysis Using the
`Subtraction Method in Indocyanine Green Angiography,”
`European Journal of Ophthalmology, vol. 6, No. 1, pp.
`30-38 (1996).
`DuBosar, “Population at Risk: Age-Related Macular
`Degeneration,” Ocular Surgery News, 10 Pages, (May 15,
`1998).
`Chen et al., “Photothermal Effects on Murine Mammary
`Tumors Using Indocyanine Green and an 808-nm Diode
`Laser: an in vivo Efficacy Study,” Cancer Lett,, vol. 98, No.
`2, pp. 169-173 (1996).
`Alcon Pharmaceuticals Ltd. “Pharmacyclics Inc.,” The Busi­
`ness and Medicine Report, p. 63 (Jan. 1998).
`Shraga et al., “Feeder Vessel Photocoagulation of Subfoveal
`Choroidal Neovascularization Secondary to Age-Related
`Macular Degeneration,” Ophthalmology, vol. 105, No. 4,
`pp. 662-669 (1998).
`Flower et al., “Clinical Infrared Absorption Angiography of
`the Choroid,” American Journal of Ophthalmology, vol. 73,
`No. 3, pp. 458-459 (1972).
`Flower et al., “A Clinical Technique and Apparatus for
`Simultaneous Angiogrpahy of the Separate Retinal and
`Choroidal Circulations,” Investigative Ophthalmology, vol.
`12(4), pp. 248-261 (1973).
`Hochheimer et al., “Angiography of the Cervix,” Johns
`Hopkins Medical Journal, vol. 135, pp. 375-382, (1974).
`Flower, “High Speed Human Choroidal Angiography Using
`Indocyanine Green Dye and a Continuous Light Source,”
`International Symposium on Fluorescein Angiography,
`Documenta Ophthmologica Proceedings Series, vol. 9, pp.
`59-64 (1976).
`Flower et al., “Indocyanine Green Dye Fluorescence and
`Infrared Absorption Choroidal Angiography Performed
`Simultaneously with Fluorescein Angiography,” Johns Hop­
`kins Medical Journal, vol. 138, No. 2, pp. 33-42 (1976).
`Orth et al., “Potential Clinical Applications of Indocyanine
`Green Choroidal Angiography,” The Eye, Ear, Nose and
`Throat Monthly, vol. 55, Jan., pp. 15-28, 58 (1976).
`
`Patz et al., “Clinical Applications of Indocyanine Green
`Angiography,” International Symposium on Fluorescein
`Angiography, Documenta Ophthmolgoica, vol. 9, pp.
`245-251 (1976).
`Flower, “Choroidal Fluorescent Dye Filling Patterns a Com­
`parison of High Speed Indocyanine Green and Fluorescein
`Angiograms,” International Ophthalmology, vol. 2(3), pp.
`143-150 (1980).
`Hyvarinen et al., “Indocyanine Green Fluorescence Angiog­
`raphy,” ACTA Ophthalmologica, vol. 58, pp. 528-538
`(1980).
`Bischoff et al., “Ten Years Experience with Choroidal
`Angiography Using Indocyanine Green Dye-A New Rou­
`tine Examination or an Epilogue,” Doc Ophthalmology, vol.
`60(3), pp. 235-291 (1985).
`Murphy et al., “Effects of Retinal Photocoagulation on the
`Choroidal Circulation,” Investigative Ophthalmology &
`Visual Science, vol. 32(4), p. 785 (1991) Meeting Abstract.
`Murphy et al., “Indocyanine Green Angiographic Studies of
`Occult Choroidal Neovascularization,” Investigative Oph­
`thalmology & Visual Science, vol. 43(4), p. 1134 (1993)
`Meeting Abstract.
`Flower, “Binding and Extravasation of Indocyanine Green
`Dye,” Retina, vol. 14, No. 13, pp. 283-284 (1994).
`Lim et al., “Indocyanine Green Angiography,” International
`Ophthalmology Clinics, vol. 35(4), pp. 59-70 (1995).
`Hiner et al., “A Previously Undescribed Indocyanine Green
`Angiographic Filling Pattern,” Investigative Ophthalmology
`& Visual Science, vol. 36, No. 4 (1995) Summary Meeting
`Abstract.
`Flower et al., “Disparity Between Fundus Camera and
`Scanning Laser Ophthalmoscope Indocyanine Green Imag­
`ing of Retinal Pigment Epithelium Detachments,” Retina,
`vol. 18(3), pp. 260-268 (1998).
`Staurenghi et al., “Laser Treatment of Feeder Vessels in
`Subfoveal Choroidal Neovascular Membranes,” Ophthal­
`mology, vol. 105, No. 12, pp. 2297-2305 (1998).
`Flower et al., “Expanded Hypothesis on the Mechanism of
`Photodynamic Therapy Action on Choroidal Neovascular­
`ization,” Retina, vol. 19, No. 5 pp. 365-369 (1999).
`Flower, “Experimental Studies of Indocyanine Green
`Dye-Enhanced Photocoagulation of Choroidal Neovascu­
`larization Feeder Vessels,” American Journal of Ophthal­
`mology vol. 129, No. 4, pp. 501-512 (2000).
`Mendelson et al., “Amelioration of Experimental Lipid
`Keratopathy by Photochemically Induced Thrombosis of
`Feeder Vessels,” Arch Ophthalmol, vol. 105, Jul. 1987 (pp.
`983-988).
`Tsilimbaris et al., “Photothrombosis Using Two Different
`Phthalocyanine Administration Routes: Continuous I.V.
`Infusion v. Bolus I.V. Injection,” Photochem. Photobiol,,
`62(3), 1995, (pp. 435-441).
`Spinelli et al., “Endoscopic Treatment of Gastrolintestinal
`Tumors: Indications and Results of Laser Photocoagulation
`and Photodynamic Therapy,” Seminars in Surgical Onocol-
`ogy, 11 (4), 1995, (pp. 307-318) (Abstract only).
`Von Kerczek et al., “The Effects of Indocyanine Green
`Dye-Enhanced Photocoagulation on the Blood Flow in the
`Choriocapillaris and the Choroidal Neovascularization,”
`Advances in Heat and Mass Transfer in Biotechnology,
`2000, (pp. 1-3). (Abstract only).
`* cited by examiner
`
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`

`1
`METHODS FOR DIAGNOSING AND
`TREATING CONDITIONS ASSOCIATED
`WITH ABNORMAL VASCULATURE USING
`FLUORESCENT DYE ANGIOGRAPHY AND
`DYE-ENHANCED PHOTOCOAGULATION
`FIELD OF THE INVENTION
`The present invention relates generally to methods for
`diagnosing and treating conditions associated with abnormal
`vasculature.
`BACKGROUND OF THE INVENTION
`Fluorescent dyes, such as indocyanine green (ICG), have
`been used for years in connection with angiography to
`diagnose and treat vascular abnormalities that occur in the
`eye, e.g., choroidal neovascularization (CNV). CNV is a
`cause of Age-Related Macular Degeneration (ARMD),
`which is the leading cause of significant visual impairment
`in the elderly.
`CNV originates in the choroidal blood vessels, the latter
`lying adjacent the retina of the eye. When CNV forms, it
`may intrude into and displace a portion of the sensory retina
`from its normal position, thereby distorting vision. Vision
`may also be blocked entirely if hemorrhage of the CNV
`occurs.
`One method of diagnosing and treating ARMD is by laser
`photocoagulation of the CNV. This treatment, however, is
`successful to the extent that the CNV can be accurately
`mapped. This is because the CNV is, by definition, in the
`macular area and often encroaches on the fovea. Application
`of photocoagulation close to the fovea can result in the
`destruction of high acuity vision and/or accelerated growth
`of the CNV.
`Generally, mapping of CNV is completed using angio­
`grams. Angiograms are images of blood vessels, obtained by
`injecting a fluorescent dye into the blood stream prior to
`obtaining an image. As any of several dyes may be used, and
`because each dye fluoresces at its own particular
`wavelength, a radiation source that emits light (radiation) at
`that particular wavelength (e.g., a low-powered laser pro­
`vided using fiber optic cables incorporated into a fundus
`camera) is used to illuminate the eye. Such a light source is
`part of a fundus camera, which also includes a CCD video
`camera. At or about the time of dye injection into the animal,
`the fundus camera begins capturing images, i.e.,
`angiograms, of the eye at specific time intervals. The angio­
`grams provide a record of the extent of dye movement
`within the ocular vasculature at each specific time interval.
`More specifically, after the dye is injected into the body,
`the dye enters the vasculature of the eye and begins to
`fluoresce due to the presence of the appropriate excitation
`radiation (light). The fluorescing dye, being mixed with the
`ocular blood, provides each angiogram with an accurate
`illustration of the extent of ocular blood flow through the
`ocular vasculature at that moment. By comparing a series of
`angiograms of the same vasculature over a given time
`period, one is able to map the vasculature and determine the
`location of a CNV, and may then move to treat this
`abnormality, e.g., by laser photocoagulation of the CNV
`itself.
`While the foregoing methodology has met with success,
`several issues remain. One is the clarity of the angiograms
`obtained using the previously described diagnostic methods.
`Clearly, any improvements in the angiogram clarity would
`result in a more accurate diagnosis, and, more significantly,
`allow a physician to more accurately locate a CNV requiring
`treatment.
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`US 6,351,663 B1
`
`2
`Further, the medical uses of fluorescent dyes outside of
`the foregoing diagnosis and treatment procedures has been
`relatively limited. Other known uses for one such dye, ICG,
`are limited to diagnostic procedures, such as determining
`cardiac output, hepatic function and liver blood flow.
`Accordingly, a need exists for methods of diagnosing and
`treating ocular vascular abnormalities, e.g., CNV, that over­
`come the aforementioned problems inherent in known meth­
`ods of fluorescent dye angiography and photocoagulation.
`Further, and in view of the successful use of fluorescent dyes
`as diagnostics for certain limited conditions, i.e., ophthalmic
`angiograms, hepatic function and liver blood flow and
`cardiac output, there remain questions as to whether the use
`of these dyes can successfully be expanded into the diag­
`nosis and/or treatment of other conditions and disorders.
`SUMMARY OF THE INVENTION
`The present invention meets the foregoing and other
`needs in a variety of ways. In a first aspect, the present
`invention provides a method for enhancing the clarity of
`fluorescent dye angiograms using relatively high dye
`concentrations, leading to more accurate targeting of vessels
`during treatment. In a second aspect, the present invention
`provides a method that allows blood vessels feeding various
`types of abnormalities to be more readily identified, and
`thereafter treated. Several other aspects of the present inven­
`tion provide new methods of diagnosis and treating abnor­
`malities and conditions using fluorescent dyes. All of the
`inventive aspects may be used on animals, e.g., humans,
`dogs, cats, but are preferably used in connection with the
`diagnosis and treatment of human subjects.
`In particular, the present invention is able to provide
`angiograms of enhanced clarity by administering a plurality
`of relatively small boluses at relatively high dye concentra­
`tions to an animal undergoing an angiographic procedure. In
`particular, the method includes introducing boluses of about
`0.1 ml to about 1.0 ml of a liquid composition at spaced time
`intervals into the animal to at least partially fill the blood
`vessels with the composition, wherein the liquid composi­
`tion comprises a relatively high fluorescent dye and a carrier.
`For example, when using ICG, the dye concentration would
`be at least about 30 mg/ml, preferably at least about 40
`mg/ml and most preferably at least about 50 mg/ml. Light
`energy of a type and in an amount sufficient to cause the dye
`in each bolus to fluoresce as the dye flows through the blood
`vessels is then applied, and angiographic images obtained.
`Another aspect of the present invention provides a method
`for determining the direction of blood flow within a vessel.
`This may allow a physician to more readily determine
`whether a particular vessel is feeding an abnormality, indi­
`cating that it should be treated. The method includes at least
`the steps of administering a liquid composition comprising
`a fluorescent dye and a carrier into the animal to at least
`partially fill the blood vessel with the composition. Energy
`of a type and in an amount sufficient to cause the dye in the
`blood vessel to fluoresce is then applied. Subsequently,
`energy of a type and in an amount in excess of that required
`to cause the dye to fluoresce is applied to a portion of the
`fluorescing dye passing through the blood vessel to cause
`that portion of the fluorescing dye to stop fluorescing. A
`series of angiographs of both the fluorescing dye, and of the
`subsequent non-fluorescing portion thereof (also referred to
`as the “bleached” dye portion), are obtained, and those
`angiograms are compared to determine the direction of
`relative movement of the bleached dye. The direction of
`relative movement of the bleached dye portion indicates the
`direction of relative movement of the blood flow in the blood
`vessel.
`
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`US 6,351,663 B1
`
`3
`Other aspects of the present invention involve new indi­
`cations for fluorescent dyes. For example, one indication
`permits a physician to locate a tumor in or adjacent to the
`wall of a body cavity of an animal. This method includes
`administering a liquid composition comprising a fluorescent
`dye and a carrier into the animal to at least partially fill the
`blood vessels of the body cavity with the composition;
`applying energy of a type and in an amount sufficient to
`cause the dye to fluoresce as the dye flows through the blood
`vessels of the body c obtaining at least one angiographic
`image of the fluorescing dye as the dye flows through the
`blood vessels of the body cavity; and analyzing the angio­
`graphic image obtained in the prior step to determine
`whether a tumor is present in or adjacent to the wall of the
`body cavity. Related methods for diagnosing other types of
`lesions, e.g., ruptured blood vessels, abnormal vasculature,
`are also provided.
`In other important aspects, the present invention provides
`methods for treating the aforementioned conditions. One
`exemplary method reduces the blood flow through a vessel
`that carries blood into a tumor of an animal. This method
`comprises administering a liquid composition comprising a
`fluorescent dye and a carrier into the animal to at least
`partially fill a blood vessel that carries blood into a tumor
`with the composition, and applying energy to the blood
`vessel of a type and in an amount sufficient to excite the dye
`in the blood vessel, thereby increasing the temperature of
`any liquid adjacent the dye, the increase in temperature
`causing the blood within the vessel to coagulate relatively
`quickly, thereby reducing (and preferably halting
`completely) the rate of blood flow through that vessel into
`the tumor.
`Other related aspects of the present invention include
`methods for reducing or eliminating tumors. These methods
`are preferably used after the tumors have been located using
`fluorescent dye angiography, the latter providing a means for
`precisely locating a tumor in a subject. Once the precise
`location of a tumor is determined, methods including dye-
`enhanced photocoagulation, direct injection of chemothera­
`peutic and/or anti-angiogenesis agents into the tumor, con­
`ventional application of radiation, and surgical removal of
`the tumor, are expected to be effective against the tumor
`when used either alone or in combination. These methods
`have the advantage of lessening patient trauma because the
`treatment can be closely focused on the tumor alone as
`opposed to the tumor and other healthy body tissue, and may
`be used in combination in a single treatment session. For
`example, a single session can include dye-enhanced photo­
`coagulation of those vessels feeding blood into the tumor
`using an endoscope, followed by injection of chemothera­
`peutic and anti-angiogenesis agents via the endoscope
`directly into the tumor itself (as opposed to conventional IV
`administration).
`The various aspects of the present invention will be more
`clearly understood upon reference to the following preferred
`embodiments.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`Turning initially to the issues associated with angiogram
`clarity, a first aspect of the present invention provides a
`method for enhancing the resolution of angiograms. This
`enhancement is provided by the introduction of a plurality of
`relatively small, yet highly dye-concentrated, boluses of a
`fluorescent dye composition into an animal, and subse­
`quently obtaining angiograms as the composition passes
`
`4
`through the vasculature of interest. The use of this method
`provides for a greater degree of fluorescence in the
`composition, and hence greater resolution in the associated
`angiogram, as compared to angiograms obtained using a
`composition having a conventional dye concentration.
`Prior to the discovery of the present invention, there was
`no recognized need in any diagnostic or therapeutic proce­
`dure for using a fluorescent dye at a relatively high concen­
`tration. For example, one example of a suitable dye, ICG,
`has been marketed for years for use in angiography. The
`present package insert for IC-GREEN™ (ICG, manufac­
`tured by Akom, Inc., Decatur, 111.) suggests an optimal
`concentration of 20 mg ICG/ml for angiography (at 2 ml,
`providing a total ICG dose of 40 mg), depending upon the
`imaging equipment and technique used.
`In contrast, this aspect of the invention includes introduc­
`ing boluses of a liquid composition comprising a fluorescent
`dye at a concentration that is higher than that previously
`used. This concentration should be at least about 1.5 times
`(e.g., about 30 mg/ml for ICG), preferably at least about 2
`times (e.g., about 40 mg/ml for ICG) and most preferably
`about 2.5 times (e.g., at least about 50 mg/ml for ICG) the
`highest known angiographic diagnostic concentration. The
`boluses are advantageously small in volume, about 0.1 ml to
`about 1.0 ml, and may be of the same or different volume.
`The boluses are introduced at spaced time intervals into an
`animal to at least partially fill the blood vessels of interest
`with the composition. After this administration, light energy
`of a type and in an amount sufficient to cause the dye to
`fluoresce as the dye flows through the blood vessels is
`applied, in accordance with procedures known in the art, and
`angiographic images are obtained. The images obtained
`provide higher levels of resolution than those obtained using
`conventional dye (e.g., ICG) compositions.
`While not being bound to any particular theory, it is
`believed that the enhancement of resolution is due to the
`greater number of dye molecules present in a given wave
`front transiting a blood vessel, and a recognition that CCD
`cameras (typically used to obtain angiographic images)
`generate relatively high signal-to-noise ratios. With the
`relatively greater number of dye molecules being present in
`a particular dye “wave front,” a greater the number of
`photons are generated by the dye upon exposure to radiation,
`providing better image quality even when the relatively high
`signal-to-noise ratio CCD cameras are used.
`The total quantity of the liquid composition administered
`through a plurality of boluses (or as a single bolus, if
`desired) should be sufficient to permit readable angiographic
`images to be obtained and analyzed when using a CCD
`camera. This quantity may equal that administered using
`conventional formulations, but is advantageously greater,
`e.g., at least about 1.5 times the amount of dye administered
`using conventional formulations. More advantageously, at
`least twice that amount, preferably at least three times that
`amount, and most preferably, at least five times the amount
`of conventional formulations is administered. Optionally,
`after the administration of each bolus, a saline flush can be
`administered to aid the circulation of the liquid composition
`throughout the blood vessels of interest.
`The dyes useful in the present invention should be able to
`fluoresce in the presence of radiation of a certain
`wavelength, and to permit angiographic images of blood
`vessels of higher quality to be obtained as compared to
`angiograms obtained using conventional dye concentrations.
`Preferably, the dyes should also be able to generate thermal
`energy when exposed to radiation. The dyes should therefore
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` NOVADAQ TECHNOLOGIES
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`5
`be selected to at least permit diagnostic procedures, while
`preferred dyes function for both diagnostic and treatment
`procedures.
`Treatment methods using dye-enhanced photocoagulation
`discussed herein comprise applying radiation of a certain
`wavelength (based upon the dye used) on a portion of an
`undesirable dye-carrying blood vessel. The radiation wave­
`length is selected to “excite5’ the dye; the absorption of such
`radiation by the dye causes the temperature of the dye to
`increase. As the correlation between radiation wavelength
`and increase in dye temperature is well known to those
`skilled in the art, this data will not be repeated herein. As the
`dye temperature increases, the temperature of the surround­
`ing blood and vessel tissue increase. This increase in tem­
`perature hastens the rate at which blood clots in and adjacent
`that portion of the vessel onto which the radiation is applied.
`This clotting, in turn, leads to partial, or preferably
`complete, obstruction of the vessel in or adj acent the portion
`of the vessel onto which the radiation was applied.
`The dye-containing composition used in this and the other
`treatment methods disclosed herein may vary widely. One
`limit on the dye concentration is that sufficient dye should be
`present in composition, and more importantly the targeted
`vessel, to permit at least partial obstruction of the target
`vessel by the dye-enhanced photocoagulation methods dis­
`cussed herein. Further, the novel diagnostic methods dis­
`closed in the following paragraphs may also use a wide
`range of dye concentrations, with the limitation that suffi­
`cient dye should be present in the composition (and targeted
`vessels) to permit the angiograms taken in conjunction with
`those methods to be analyzed.
`One method of determining the degree of vessel obstruc­
`tion is by analyzing angiograms taken after treatment is
`completed, and after the dye has left the treated vessel. For
`example, if the treatment results in total obstruction of a
`CNV feeder vessel, an angiogram of the downstream portion
`of the vessel, e.g., the CNV itself, will not reveal any dye
`fluorescence. Partial obstruction should reveal a lower
`degree of fluorescence.
`A number of fluorescent dyes are known that are accept­
`able for use in the composition of the various inventive
`methods described herein. Exemplary dyes include
`fluorescein, rose bengal, ICG and analogue members of the
`tricarbocyanine dyes, and any other dye which meets the
`criteria described herein for diagnosis and/or treatment
`procedures. The preferred fluorescent dye is ICG because it
`is readily available, has long been approved for administra­
`tion to humans for ophthalmic angiography and other unre­
`lated indications, and is suitable for both diagnosis and
`treatment procedures. As the peak absorption and emission
`of ICG lies in the range of 800-850 nm, a light source
`emitting such wavelengths should be used when obtaining
`angiographic images during diagnosis, as well as during any
`subsequent treatment procedure.
`The dye compositions may further include a
`pharmaceutically-acceptable carrier. The carrier enhances
`the administration of the fluorescent dye to a patient, the
`latter being either intravenously or by other suitable means.
`The choice of carrier will be determine in part by the
`particular fluorescent dye used, as well as by the particular
`route of administration of the liquid composition. The carrier
`should be compatible with both the fluorescent dye and the
`tissues and organs of the subject that come into contact with
`the liquid composition. Moreover, the carrier should not
`interfere with the energy applied or angiographic images
`obtained following administration.
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`US 6,351,663 B1
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`Illustrative of suitable carriers include water, saline,
`alcohols, red blood cells (RBC), glycerin, polyethylene
`glycol, propylene glycol, polysorbate 80, Tweens,
`liposomes, amino acids, lecithin, dodecyl sulfate, lauryl
`sulfate, phospholipid, Cremophor, desoxycholate, soybean
`oil, vegetable oil, safflower oil, sesame oil, peanut oil,
`cottonseed oil, sorbitol, acacia, aluminum monstearate,
`polyoxyethylated fatty acids, povidone and mixtures
`thereof. Advantageously, the carrier is water. Preferably,
`however, the composition will include components that
`increase the degree of dye fluorescence, e.g., alcohols such
`as ethanol and surfactants such as the Tweens. Optional
`components that may be present in the composition include
`tonicity and/or pH adjusters, e.g., NaOH, HC1, tribuffer
`phosphate, tris buffer and the like. In addition, the compo­
`sition may include thrombin or other known blood clotting
`compounds that would function to further enhance blood
`clotting during and after treatment.
`The fluorescent dye composition may initially be pro­
`vided as a lyophilizate for reconstitution before use, or as a
`pre-mix, in a vial or syringe.
`As mentioned above, and in a related aspect of the present
`invention, RBCs may be used as a carrier for the fluorescent
`dye. This technique is referred to herein as RBC doping. The
`RBC as a carrier has advantages in that it is a normal
`constituent of circulating blood and, despite the relative
`large volume (and hence large dye-carrying capacity) of
`each RBC, RBCs can nevertheless readily move throughout
`the circulatory system'—deforming to enable movement
`through even the small diameter capillaries. Further, and
`while not desiring to be bound to any particular theory, the
`use of doped RBCs provides additional advantages pertain­
`ing to clot formation. In particular, the size of clot formed
`during the treatment methods described herein depends upon
`the amount of dye present at the vessel treatment site, the
`amount of radiation energy delivered thereto and the distri­
`bution of the dye molecules associated with the RBCs. The
`greater the number of dye molecules associated with the
`RBCs, the more sizable the clot will be when exposed to
`appropriate radiation during the treatment phase. Of course,
`if the clot is large enough, vessel closure will be permanent.
`However, if smaller, as is often the case using conventional
`treatment methods, the clot will resolve, requiring additional
`treatment. The doping of dye in RBCs reduces the variability
`in clot formation because it increases the fraction of dye
`molecules associated with RBCs at the treatment site,
`thereby increasing the probability that a sizable clot is
`formed during treatment.
`The object of the procedure is to remove the content of the
`RBCs, and then refill the RBCs with hemoglobin and dye,
`e.g., ICG, and, if desired, other clot potentiating compounds,
`e.g., fibrin, When the use of RBC doping is indicated, the
`following exemplary procedure may be followed to provide
`the doped composition for use in the various