Abstract:
An intra-vascular balloon ( 110 ), comprising a balloon body ( 1010 ); and at least one springy and elongate stave ( 1030 ) attached to said balloon and conforming to a surface of said balloon, such that said stave can apply contact force to an object in contact with said balloon.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a continuation in part of U.S. application Ser. No. 09/534,968, filed Mar. 27, 2000 the disclosure of which is incorporated herein by reference. This application is also a continuation in part of PCT/IL01/00284, filed on Mar. 27, 2001 which designates the US and was published as PCT publication WO 01/72239 A2 in the English language. This application is also a continuation in part of PCT applications PCT/IL02/00805, published as WO 03/028522 and PCT/IL03/00303, filed Apr. 10, 2003. All of these PCT applications designate the US.  
         [0002]     This application also claims priority from the following applications: Israel Application No. 151162, filed on Aug. 8, 2002, Israel Application No. 152366, filed on Oct. 17, 2002 and Israel Application No. 153753, filed on Dec. 30, 2002.  
         [0003]     The disclosure of all of the above documents is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0004]     The present invention relates to devices for reducing blood flow through the coronary sinus.  
       BACKGROUND OF THE INVENTION  
       [0005]     Occlusion of coronary arteries is a leading cause of death, especially sudden death, in what is commonly called a “heart attack”. When blood flow to a portion of the heart is suddenly stopped, the portion becomes ischemic and its electrical activity is disrupted. As the activity of the heart is mediated by electrical signal propagation, such disruption typically propagates to the rest of the heart, disorganizes the heart&#39;s activation and causes the heart output to be reduced drastically, which leads to ischemia and further damage beyond what was caused directly by the blockage.  
         [0006]     If a patient survives the direct effects of the heart attack, the damage to the heart may predispose the patient to future electrical disorders and/or may significantly reduce the coronary output, thus reducing quality of life and life expectancy.  
         [0007]     Angina pectoris is a chronic, or semi-chronic, ischemic coronary condition that occurs in the presence of occluded coronary arteries. Increased blood flow is required by the heart during exertion, but occluded arteries cannot provide the required increase in flow. The resultant ischemia produces pain, referred to as angina pectoris, that is not in itself life-threatening but may significantly reduce the quality of life.  
         [0008]     The heart has natural mechanisms to overcome occlusion in coronary arteries. One such mechanism is angiogenesis, in which new arteries are created within the coronary tissue to bypass the occluded vessels. As angiogenesis does not usually occur to any great degree naturally, various procedures have been suggested to encourage it. For example Trans-Myocardial Revascularization (TMR) is a process in which multiple holes are drilled in the heart with the intent of causing new vessels to be created.  
         [0009]     The venous circulation of the heart itself is primarily composed of a network of coronary veins that typically flow into a vein known as the coronary sinus. The coronary sinus is, “about 2 or 3 cm long, lying posterior in the coronary sulcus between the left atrium and ventricle. Its tributaries are the great, small and middle cardiac veins, the posterior vein of the left ventricle and the oblique vein of the left atrium, all except the last having valves at their orifices.” (Gray&#39;s Anatomy 38 th  Edition, page 1575) The right atrium, into which the coronary sinus drains, collects all venous blood from the body.  
         [0010]     Constriction of the coronary sinus to reduce the flow of venous blood that passes through it to the right atrium has been shown to promote angiogenesis. (“The Surgical Management of Coronary Artery Disease: Background, Rationale, Clinical Experience” by C. S. Beck and B. L. Brofman, 1956, by the American College of Physicians in Annals of Internal Medicine Vol. 45, No. 6, December 1956)  
         [0011]     However, installing a coronary sinus constricting device requires open heart surgery and the temporary removal of the heart from the pericardium, a taxing procedure for any patient, particularly the patient with compromised coronary circulation. The method of promoting angiogenesis by installing a coronary sinus blood flow reducing implant during open-heart surgery, has fallen in disfavor, probably due to the hazardous associated installation procedure.  
         [0012]     Ruiz in U.S. Pat. No. 6,120,534 teaches a flow reducing stent for use in a pulmonary artery to control damage to the lungs in a newborn that exhibits multiple, life-threatening cardio-pulmonary deformities. However, the thick, muscular, resilient walls of a pulmonary artery present a vastly different implant environment than the thin, weak non-muscular walls of the sinus and the flow dynamics that must be controlled in a pulmonary artery are vastly different than those of the coronary sinus.  
         [0013]     U.S. application Ser. No. 09/534,968, filed Mar. 27, 2000 the disclosure of which is incorporated herein by reference, proposes a basic design for a coronary sinus flow restricting implant that is delivered percutaneously to its installation site and then expanded to provide flow reduction.  
       Principles of Angiogeneis  
       [0014]     To influence the flow of blood in a vessel of the body, there are many types of implants available, perhaps most notably, stents that expand within coronary arteries to increase blood flow along the vessel sector in which the stent is implanted. These flow-influencing implants differ from the present invention in a number of fundamental ways due to the radically divergent vessel architecture of the coronary sinus and/or the radically different goals for a flow reducing implant that is implanted in the coronary sinus.  
         [0015]     The coronary sinus is a vein, albeit of a larger diameter than most veins, through which the blood from the various veins of the heart passes on its way to the right atrium from which it is sent to the lungs for oxygenation. The coronary sinus, like other veins of the body, lacks the thick muscular walls of arteries and may be damaged due to excess pressure. Hence, flow reducing implant should be transportable within blood vessels in a compact size and, following delivery, expand in the coronary sinus without causing undue stress on the relatively weak venous walls.  
         [0016]     As the pressure the flow reducing implant places on the coronary sinus walls must be limited, additional methods may be required to anchor the flow reducing implant against the sinus walls. For example a flow reducing implant may promote coronary tissue ingrowth into its surface so it anchors properly in the coronary tissue.  
         [0017]     Alternatively or additionally, the flow reducing implant should comprise materials that prevent coagulation, embolism formation and/or bacterial colonization in the coronary sinus and/or general circulation. Further, as the coronary sinus often exhibits varying cross sectional diameter and/or configuration along its length, the flow reducing implant may need to exhibit diameter variations that conform to the variable diameter of the coronary sinus.  
         [0018]     There may be a fine line between the amount of reduction of blood flow that promotes angiogenesis and when such reduction causes untoward sequella, for example damage to coronary venous valves. Further, the amount of restriction in blood flow that is required to promote angiogenesis may vary from individual to individual and may not be readily apparent until following installation. Therefore, the flow reducing implant may require that the amount of flow reduction be adjustable in situ, perhaps even on multiple occasions, with low risk to the patient health.  
         [0019]     Alternative or additional factors that promote angiogenesis may include changes in sinus blood flow dynamics. The flow reducing implant, therefore, may incorporate one or more design configurations to promote one or more changes in blood flow dynamics:  
         [0020]     (a) Increased pressure in the coronary capillaries and/or increased perfusion duration.  
         [0021]     (b) Increased resistance of the venous system to promote one or more of the following: 
        i) redistribution of blood flow in coronary arteries;     ii) increased intra-myocardial perfusion pressure; and     iii) increased intra-myocardial pressure.        
 
         [0025]     (c) Increased arterial diastolic pressure (by restricting venous drainage) that causes the arterial auto-regulation to start working again, for example, such an auto regulation as described in Braunwald “Heart Disease: A Textbook of Cardiovascular Medicine”, 5th Edition,  1997 , W. B. Saunders Company, Chapter  36 , pages 1168-1169.  
         [0026]     (d) Changes in pressure of sinus blood flow against the valve leading to the right atrium.  
         [0027]     (e) Changes in blood stream dynamics such as laminar blood flow and/or blood stream rotation.  
         [0028]     The amount of blood flow dynamics that stimulate angiogenesis may vary from individual to individual so the flow reducing implant may require a design that allows variation of blood flow dynamics, without risk to the patient, following implantation.  
         [0029]     In an exemplary embodiment of the present invention, one or more of flow reducing implant designs may foster angiogenesis when implanted in one or more coronary arteries. Further, in an exemplary embodiment of the present invention, one or more features of flow reducing implant designs presented herein may foster angiogenesis when implanted in one or more coronary arteries. It is therefore understood that in accordance with promoting angiogenesis in the heart, any features of the flow reducing implants described herein may be modified for use in one or more coronary arteries.  
         [0030]     In an exemplary embodiment of the present invention, one or more flow reducing implant designs may foster angiogenesis through implantation in one or more vessels of the body outside of the coronary vessels. For example, angiogenesis in the kidney may be promoted by implanting a flow reducing implant in a vessel of the kidney. It is therefore understood that in accordance with promoting angiogenesis in other regions of the body, the flow reducing implant described herein may be modified for use in one or more non-coronary vessels of the body.  
       SUMMARY OF THE INVENTION  
       [0031]     An aspect of some embodiments of the invention relates to a percutaneously deliverable flow reducing implant that reduces blood flow in the coronary sinus. In an exemplary embodiment of the present invention, the flow reducing implant promotes angiogenesis, thereby reducing ischemia and/or its crippling sequella including heart attack and death.  
         [0032]     In an exemplary embodiment, the flow reducing implant comprises a hollow member having a flow passage in which at least a portion of said flow passage has a smaller cross section than a cross section of the coronary sinus. Optionally, the flow reducing implant is deliverable, for example, in a compact form via a delivery sheath to the coronary sinus where it attains its final configuration.  
         [0033]     Optionally, the flow reducing implant configuration may be altered after implantation in the coronary sinus to change the amount of blood flow reduction and/or blood flow dynamics. Alternatively or additionally, the contact pressure between the flow reducing implant and the coronary sinus may be varied.  
         [0034]     In an exemplary embodiment, at least a portion the flow reducing implant is self expanding. Optionally, the flow reducing implant comprises, for example, longitudinal and/or transverse slits of varying length to govern the expanded shape of the flow reducing implant. Optionally, the flow reducing implant comprises materials with a shape memory so the flow reducing implant automatically attains a desired shape following release, for example, from a delivery catheter into the coronary sinus. Alternatively or additionally, a standard catheter balloon is used to expand the flow reducing implant into its desired shape. Alternatively or additionally, a catheter balloon with a specialized shape is used to cause expansion of the flow reducing implant. Alternatively or additionally, the flow reducing implant is inflatable.  
         [0035]     In an exemplary embodiment, the flow reducing implant comprises a material that changes size and/or configuration as it absorbs material from its environment. In an exemplary embodiment, the flow reducing implant absorbs liquid from the blood flowing through the coronary sinus to change its size and/or configuration.  
         [0036]     In an exemplary embodiment, the flow reducing implant defines a flow passage that promotes angiogenesis by changing blood flow dynamics. For example, the flow reducing implant comprises at least one extension flap along its flow passage that extends, for example, into the flow passage. Optionally, the angle of the one or more flaps in relation to the blood flow, and/or its size, is adjustable following implantation of the flow reducing implant.  
         [0037]     In an exemplary embodiment, the at least one extension extends from a sheath encircling at least a portion of the outside of the flow reducing implant. Optionally, the at least one extension comprises one or more curved members substantially planar with, for example, an outer surface of said flow reducing implant.  
         [0038]     In an exemplary embodiment, the body of the flow reducing implant and/or the one or more extension flaps comprise a single solid wall. Alternatively or additionally, one or more extension flaps comprise outer and inner walls with a space between them. Optionally, the space is inflatable. Optionally, the flow reducing implant comprises two or more extension flaps, for example with one or more extension flaps located at each end of the flow reducing implant.  
         [0039]     An aspect of some embodiments of the invention relates to a percutaneously deliverable coronary sinus flow reducing implant comprising at least one wire extending from at least one end of said flow reducing implant. In an exemplary embodiment, the at least one wire extends into the coronary sinus and is shaped to change blood flow dynamics, enhance anchoring of the flow reducing implant, and/or enhance reduction in size and/or positioning of the flow reducing implant. Alternatively or additionally, the at least one wire is attached along the flow passage and extends, for example, into the coronary sinus.  
         [0040]     In an exemplary embodiment, the at least one wire comprises at least two wires. Optionally, the at least two wires are joined along their middle section within the flow passage of the flow reducing implant. Alternatively or additionally, the area where they are joined extends beyond the flow passage into the coronary sinus.  
         [0041]     Alternatively or additionally, at least a portion of the central portions of said at least two wires are joined to a ring that alters blood flow dynamics. In an exemplary embodiment, the wires are joined to the ring in a manner that reduces blood turbulence, for example with curved connecting pieces to the ring. Alternatively or additionally, at least a portion of the central portions of said at least two wires are joined to a sphere, said sphere causing a change in blood flow dynamics to promote angiogenesis.  
         [0042]     An aspect of some embodiments of the invention relates to a percutaneously deliverable coronary sinus flow reducing implant comprising at least one shape-conforming element that changes in geometry, thereby adjusting the size and/or configuration of the flow passage of the flow reducing implant. In an exemplary embodiment, the configuration of the one or more shape-conforming elements is governed by one or more impulses, for example, RF, ultrasound, low frequency sound, heat, electricity, electromagnetic and/or radiation. Optionally, one or more impulses are initiated from an initiation area near the one or more shape-conforming elements. Alternatively or additionally, the one or more impulses are initiated external to the heart, for example, external to the patient. In an exemplary embodiment, the configuration of the one or more shape-conforming elements is governed by one or more chemical reagents.  
         [0043]     An aspect of some embodiments of the invention relates to a percutaneously deliverable coronary sinus flow reducing implant with one or more slits governing its implanted configuration and/or size and/or at least one ripple and/or a bend that defines and/or provides adjustment in configuration and/or size of the flow reducing implant.  
         [0044]     In an exemplary embodiment, a flow reducing implant comprises a cord that, for example, encircles at least a portion of its diameter, in accordance with an exemplary embodiment of the invention. In an exemplary embodiment, the cord coronary sinus flow reducing implant changes in size and/or configuration by adjusting the size of the encircling cord and/or severing the cord.  
         [0045]     Alternatively or additionally, the flow reducing implant wall has two edges that overlap each other. As the cord expands, the edges on the at least one wall of the cord type flow reducing implant move in relation to each other, thereby providing one or more expansion diameters.  
         [0046]     An aspect of some embodiments of the invention relates to a percutaneously deliverable balloon catheter that achieves one or more expansion pressures to cause the expansion and/or modification of a flow reducing implant shape. In an exemplary embodiment, the balloon catheter comprises at least one stave along its surface that contacts at least a portion of a flow reducing implant during expansion of the flow reducing implant. In an exemplary embodiment, the balloon and/or one or more staves comprise materials configured to reduce in size to a compact profile, thereby allowing the catheter to be easily positioned and/or repositioned in relation to a flow reducing implant.  
         [0047]     In an exemplary embodiment, the one or more staves of the balloon catheter comprise two or more staves. Optionally, the two or more staves are curved and/or connected at one or more places to provide a springy frame around the balloon. Optionally, the two or more curved staves foster, for example, a compact size during position and/or repositioning. Optionally, the balloon catheter comprises an inflatable design and thereby provides one or more expansion pressures in addition to the expansion pressure provided by the two or more springy staves, for implantation and/or positional adjustments of a flow reducing implant.  
         [0048]     There is thus provided in accordance with an exemplary embodiment of the invention, a an intra-vascular balloon, comprising:  
         [0049]     a balloon body; and  
         [0050]     at least one springy and elongate stave attached to said balloon and conforming to a surface of said balloon, such that said stave can apply contact force to an object in contact with said balloon. Optionally, said balloon is elongate and wherein said stave is provided along a long dimension of said balloon. In an exemplary embodiment of the invention, said balloon comprises a tether attached to said balloon.  
         [0051]     In an exemplary embodiment of the invention, said at least one stave comprise a plurality of staves arranged around said balloon. Optionally, said plurality of staves are attached to each other at their ends. Optionally, said staves modify a geometry of said balloon when not inflated. Optionally, said staves are configured to compact said balloon in a resting condition thereof. Alternatively, said staves are configured to apply radially outwards pressure in a resting condition thereof.  
         [0052]     In an exemplary embodiment of the invention, said staves are distortable by an expansion of said balloon.  
         [0053]     In an exemplary embodiment of the invention, said balloon is formed of an elastic material.  
         [0054]     In an exemplary embodiment of the invention, said plurality of staves are configured to substantially surround said balloon when said balloon is collapsed.  
         [0055]     There is also provided in accordance with an exemplary embodiment of the invention, vascular implant, comprising a flexible band having a diameter suitable for implantation in a blood vessel; and a plurality of elongate axial elements mounted on said band. Optionally, said flexible band is thin.  
         [0056]     In an exemplary embodiment of the invention, said flexible band has a thickness suitable for restricting blood flow  
         [0057]     In an exemplary embodiment of the invention, said flexible band has a length substantially smaller than a length of said elements.  
         [0058]     In an exemplary embodiment of the invention, said flexible band is elastic.  
         [0059]     There is also provided in accordance with an exemplary embodiment of the invention, a blood flow reducing implant, comprising a body defining a flow channel having an cross-section which is progressively restricted along an axial direction, in which the smallest diameter of a cross-section is sized for passage of a guidewire and blockage of substantially all blood-flow therethrough. Optionally, said cross-section is monotonicly restricted along said direction. Alternatively or additionally, said smallest diameter blocks over 95% of blood flow through said implant. Alternatively or additionally, said smallest diameter is restricted by an elastic sheath.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0060]     Exemplary non-limiting embodiments of the invention are described in the following description, read with reference to the figures attached hereto. In the figures, identical and similar structures, elements or parts thereof that appear in more than one figure are generally labeled with the same or similar references in the figures in which they appear. Dimensions of components and features shown in the figures are chosen primarily for convenience and clarity of presentation and are not necessarily to scale. The attached figures are:  
         [0061]      FIG. 1  is a longitudinal section of a dual wall type flow reducing implant installed in a coronary sinus, in accordance with an exemplary embodiment of the invention;  
         [0062]      FIGS. 2A and 2B  are isometric views of two embodiments of flap type flow reducing implants, in accordance with an exemplary embodiment of the invention;  
         [0063]      FIGS. 3A-3E  show various embodiments of cone type flow reducing implants, in accordance with an exemplary embodiment of the invention;  
         [0064]      FIG. 4  is longitudinal section of a tube type flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0065]      FIG. 5  is an isometric view of a staved type flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0066]      FIGS. 6A-6C  are isometric views of three embodiments of wire cone type flow reducing implants, in accordance with an exemplary embodiment of the invention;  
         [0067]      FIG. 7  is a longitudinal section of a flow reducing implant with shape-conforming elements, in accordance with an exemplary embodiment of the invention;  
         [0068]      FIG. 8A  is a plan layout of a ripple type flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0069]      FIG. 8B  is an enlarged section of the plan layout of  FIG. 8A , in accordance with an exemplary embodiment of the invention;  
         [0070]      FIG. 8C  is an isometric view of a slit type flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0071]      FIG. 9  is a plan layout of a cord type flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0072]      FIG. 10  is an isometric view of a balloon catheter with expansion rods and a longitudinal section of a flow reducing implant, in accordance with an exemplary embodiment of the invention;  
         [0073]      FIG. 11  is an isometric view of a spring ballast catheter and a longitudinal section of a step type coronary sinus flow reducing implant, in accordance with an exemplary embodiment of the invention; and  
         [0074]      FIG. 12  shows the step type flow reducing implant of  FIG. 11  during manufacture, in accordance with an exemplary embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0075]      FIG. 1  is a longitudinal section of a dual wall type flow reducing implant  100  installed in a coronary sinus  110  with a pre-implant sinus cross section dimension  112 , in accordance with an exemplary embodiment of the invention. Flow reducing implant  100  comprises an outer wall  102  and an inner wall  104 . At least a portion of outer wall  102  contacts coronary sinus  110 . At least a portion of inner wall  104  is separated from outer wall  102  by a space  130  and defines a flow passage  114  that is narrower in diameter than coronary sinus pre-implant diameter  112 .  
         [0076]     Thus, blood flowing in a direction  116  will have a reduced flow upon exiting dual wall flow reducing implant  100  via a rear end  108  into a post implant coronary sinus  118 . In reducing blood flow in direction  116 , flow reducing implant  100  optionally promotes angiogenesis, for example, in an area of coronary tissue  120 .  
         [0077]     In an exemplary embodiment, inner wall  104  and/or outer wall  102  are resilient and dual wall flow reducing implant  100  is delivered to the deployment site in coronary sinus  110  in a reduced size, for example inside a delivery catheter  122 . Upon reaching the deployment area of coronary sinus  110 , dual wall flow reducing implant  100  is freed of delivery catheter  122  and expands, for example with pressure from an inflated balloon catheter deployed along flow passage  114 .  
         [0078]     Alternatively or additionally, a front end  106  and/or rear end  108  are resilient and have a predetermined shape memory so, even with application of an expansion force from a standard balloon catheter, they expand radially outward.  
         [0079]     In an exemplary embodiment of the invention, flow reducing implant  100  is cut out of a sheet of metal or a tube, for example, using laser, water cutting, chemical erosion or metal stamping (e.g., with the result being welded to form a tube). Alternatively, flow reducing implant  100  is woven (e.g., of metal or plastic fiber), for example, using methods well known in the art.  
         [0080]     In an exemplary embodiment, at least a portion of space  130  is filled, for example with the same material as walls  102  and/or  104 , thereby forming a solid wall. Alternatively or additionally, space  130  is filled with, for example, a different material than walls  102  and/or  104 . It should be understood that, for example, the self expanding properties (e.g. shape memory) and/or other properties and/or other embodiments of outer wall  102  and/or inner wall  104 , apply to any portion of space  130  that serves as a connection between them.  
         [0081]     Optionally, shape memory materials of flow reducing implant  100  form directly into the desired shape to provide the required flow reduction, for example, without requiring the use of a catheter balloon. Alternatively or additionally, the catheter balloon used for inflation comprises a single balloon catheter with a standard shape.  
         [0082]     Optionally, outer wall  102  is manufactured with a machining process and, for example, etched in a pattern so that a portion of its etched outer surface  124  anchors against coronary sinus  110 . Alternatively or additionally, outer surface  124  is fashioned with knobs and/or indentations that promote ingrowth of tissue  120  to provide anchoring of dual wall flow reducing implant  100 . Alternatively or additionally, the diameter of outer wall  102  may be varied along its length to conform to contact at least a portion of coronary sinus  110  when coronary sinus  110  has, for example, a variable configuration and/or diameter along its length.  
         [0083]     In an exemplary embodiment, flow reducing implant  100  comprises materials that prevent coagulation, embolism formation and/or bacterial colonization. Alternatively or additionally, inner wall  104  and/or outer wall  102  are impregnated with materials that are released over a period of time, for example one month or more or two weeks or less, depending, for example on the patient state of health. These released materials, for example, prevent coagulation, embolism formation and/or bacterial colonization.  
         [0084]     Alternatively or additionally, flow reducing implant  100  has a non-cylindrical shape, for example, polygonal or ellipsoid. It may be desirable that flow reducing implant  100  have a non-circular cross-section so that it is less likely to migrate axially. Alternatively or additionally, the cross-section shape and/or orientation optionally change along the length of flow reducing implant  100 , for example from a small diameter at end  106  to a large diameter at end  108 , or with ends  106  and/or  108  of a small diameter and a large diameter substantially in the center of flow reducing implant  100 .  
         [0085]     In some embodiments, the surfaces of front end  106  and/or rear end  108  are sloped from coronary sinus  110  toward flow passage  114 . Alternatively or additionally, surfaces of front end  106  and/or rear end  108  are sloped toward coronary sinus  110 , away from flow passage  114 . In still further embodiments, surfaces of front end  106  and/or rear end  108  are perpendicular to outer wall  102 . The difference between the various slope designs, for example, may depend on configuration of coronary sinus  110 , desired changes in blood flow dynamics and/or preventing an increase in turbulence of blood flow in direction  116  that might result in negative sequella.  
         [0086]     In an exemplary embodiment, the diameter of inner wall  104  reduces blood flow  116  of coronary sinus  110  by a specific percentage. In an exemplary procedure used in an embodiment of the present invention, an angiogram of the heart is made that includes the flow through coronary sinus  110 . The shape and/or cross sectional diameters of coronary sinus  110  are determined from the angiogram and the size and/or shape and/or configuration of flow reducing implant  100  are determined. In an exemplary embodiment, the outside diameter and configuration of flow reducing implant  100  is closely matched to the inside diameter and configuration of coronary sinus  110  to provide an optimal fit with coronary sinus  110 .  
         [0087]     In addition to design considerations that allow assumption of an installed shape and/or blood flow reduction, for example, it is desirable to reduce the amount of intrinsic movement that occurs in flow reducing implant  100  and/or other embodiments during expansion. Reducing intrinsic longitudinal movement of flow reducing implant  100  during expansion, for example, reduces potential trauma to the wall of coronary sinus  110  during installation and/or modification in shape of flow reducing implant  100 .  
         [0088]     Alternatively or additionally, a desired change in the blood volume through coronary sinus  110  is used in determining the configuration of flow reducing implant  100 . In an exemplary embodiment, in order to achieve a 50% reduction in blood flow, the cross sectional diameter of coronary sinus  110  is determined from the angiogram and flow reducing implant  100  with an appropriate diameter of narrow passage  114  is chosen to make this reduction.  
         [0089]     Alternatively or additionally, inner wall  104  diameter and/or configuration are formed to reduce blood flow to a specific level, regardless of the percentage change of flow reduction. In an exemplary embodiment, outer wall  102  is varied in diameter, for example, to maintain contact with coronary sinus  110 . However, narrow passage  114  in many flow reducing implants  100  will have a consistent diameter to restrict blood flow.  
         [0090]     Alternatively or additionally, the shape of inner wall  104  and the configuration of front end  106  and/or rear end  108  are altered to change blood flow dynamics and/or promote angiogenesis. Alternatively or additionally, the component materials of flow reducing implant may be altered to promote angiogenesis and/or to reduce untoward reaction in coronary sinus  110 .  
         [0091]     In an exemplary embodiment of the invention, flow reducing implant  100  is formed of metal, for example, a NiTi alloy (e.g., Nitinol) or stainless steel (e.g., 316L and 316LS). Alternatively, flow reducing implant  100  is formed of, or coated with, other biocompatible materials, such as nylon and/or other plastics. Optionally, flow reducing implant  100  is formed of two or more materials, for example, inner wall  104  being formed of plastic and outer wall  102  being formed of metal.  
         [0092]     Coronary sinus  110  is typified by a low degree of elasticity and is relatively susceptible to tearing (as compared to arteries). To provide safe blood flow reduction and/or flow changes that promote angiogenesis, specific considerations must be incorporated into the design of flow reducing implant  100 . The design of flow reducing implant  100 , therefore, will significantly vary over those associated with, for example, a coronary artery stent.  
         [0093]     For example, flow reducing implant  100  may require soft materials and/or soft material coating. Alternatively or additionally, flow reducing implant  100  may require materials with a low spring constant, to prevent flow reducing implant  100  from applying too much pressure on coronary sinus  110 . Alternatively or additionally, end  106  and/or end  108  may be coated with a flexible coating, for example a biocompatible material comprising a soft silicone elastomer or another soft plastic or rubber material such as latex, teflon, gortex, kevlar, latex and/or polyurethane to reduce blood flow turbulence, for example.  
         [0094]     In an exemplary embodiment, dual wall type flow reducing implant  100  is composed of inflatable material, for example silicone rubber, and upon being freed from delivery catheter  122 , it is inflated with an inflator hose  126 . Upon completion of inflation, with dual wall type flow reducing implant  100  anchored in coronary sinus  110 , for example, inflator hose  126  is pulled free of an inflator seal  128 . In an exemplary embodiment, inflator seal  128  automatically seals inflatable dual wall type flow reducing implant  100  to maintain it in the inflated state.  
         [0095]      FIG. 2A  is an isometric view of a flap type flow reducing implant  230 , in accordance with an exemplary embodiment of the invention. Flap type flow reducing implant  230  comprises three flaps  232 ,  234  and  236  that reduce blood flow in a flow passage  216  and/or promote changes in blood stream dynamics. Three flaps  232 ,  234  and  236  are shown, though there could be as few as one flap  232 , four flaps or more, depending, for example, on the amount of reduction of blood flow and/or change in blood stream dynamics flow that is desired. Flaps  232 ,  234  and  236  are shown at front end  106  of outer wall  102  though flaps  232 ,  234  and  236  could be located anywhere along flow passage  216 , including rear end  108 .  
         [0096]     Flaps  232 ,  234  and  236  are shown projecting forward of front end  106 , beyond outer wall  102 . Alternatively or additionally, they could all be planar, pointing toward each other and/or perpendicular to outer wall  102 . Alternatively or additionally, flaps  232 ,  234  and  236  could be oblique to outer wall  102  and project into flow passage  216  and/or be located at any position along flow passage  216 . Similar positioning of extensions should be understood to apply to other flow reducing implant embodiments.  
         [0097]     In an exemplary embodiment, flap type flow reducing implant  230  has inner wall  104  with a reduced diameter compared with the diameter of outer wall  102  in addition to flaps  232 ,  234  and  236 . A reduced diameter increases the reduction in the volume of blood per unit time that passes through flow passage  216  while flaps  232 ,  234  and  236  change blood stream dynamics.  
         [0098]      FIG. 2B  is an isometric view of a skewed flap type flow reducing implant  240 , in accordance with an exemplary embodiment of the invention comprising three flaps  232 ,  234  and  236  that are skewed in relation to outer surface  102 . A skewed flap type flow reducing implant  240  embodiment may prove to be beneficial in promoting angiogenesis as it changes blood stream dynamics in a robust fashion.  
         [0099]      FIGS. 3A-3E  show various embodiments of cone type flow reducing implants  330 ,  340 ,  350 ,  360  and  370 , in accordance with an exemplary embodiment of the invention. Cone projection type flow reducing implant  340  ( FIG. 3A ) comprises inner wall  104 , outer wall  102  and a cone projection  332  that encircles front end  106 . The slope and/or position of cone projection  332  in relation to outer wall  102  and/or inner wall  104  may be varied, in a variety of manners noted above, to alter blood flow dynamics and/or reducing blood flow.  
         [0100]     Sheath cone type flow reducing implant  340  ( FIG. 3B ) comprises a sheath  342  that encircles at least a portion of outer wall  102 . Connected to sheath  342  and/or an extension thereof is a sheath projection  352 , with an opening  354  to allow passage of blood flow via flow passage  216 . Sheath projection  352 , for example, can be configured with grooves to control the change in blood stream dynamics in addition to reduction of blood flow.  
         [0101]     In an exemplary embodiment, dual cone type flow reducing implant  350  ( FIG. 3C ) comprises inner wall  104  and outer wall  102  that curve at front end  106  to form a small opening  364 , causing reduction in blood flow passage  216 . As in dual wall type flow reducing implant  100 , dual cone type flow reducing implant  350  can have any combination of expandable and/or inflatable sections to achieve its configuration in the expanded state of  FIG. 3C  to promote angiogenesis. Dual cone type flow reducing implant  350  comprises thick area between all sections of walls  104  and  106  while dual cone type flow reducing implant  330  comprises cone  332  that is not as thick as the area between walls  102  and/or  104 . In an exemplary embodiment, the thick areas between walls  102  and  104  are resilient material for example that is self-expanding. Alternatively or additionally, the thick areas between walls  104  and  104  comprise a space.  
         [0102]     As noted, there are a variety of factors that can influence angiogenesis. For example, pressure of sinus blood flow against the valve inlet into the right atrium may favorably influence angiogenesis. Hence the flow pattern of the blood as it leaves coronary sinus  110  to press against the valve leading into the right atrium, may be an important factor in influencing angiogenesis.  
         [0103]     To comply with these many scenarios that may serve to promote angiogenesis, dual cone type flow reducing implant  350  may have one or a variety of design variations. For example, the design of front end  106  of dual cone type flow reducing implant  350  and/or its body may be changed to promote flow reduction, change blood stream dynamics and/or increase pressure on coronary sinus  110 . Different shapes of outer wall  102  may influence the pressures within coronary sinus  110  to similarly promote angiogenesis.  
         [0104]     Additionally or alternatively, for example, front end  106  may be convex in shape around opening  364  to achieve changes blood stream dynamics of blood flowing through coronary sinus  110 . Alternatively or additionally, front end  106  may have a flat bevel around opening  364  toward this end. In an exemplary embodiment, dual cone type flow reducing implant  350  is positioned in coronary sinus  110  with opening  364  at its front, facing the blood flow. Alternatively or additionally, dual cone type flow reducing implant  350  is positioned in coronary sinus  110  with opening  364  at its rear, facing away from the blood flow. Optionally, dual cone type flow reducing implant  350  end  106  and end  108  may both be narrowed, for example, to change blood flow dynamics of blood exiting end  108  thereby enhancing angiogenesis.  
         [0105]     In an exemplary embodiment, dual cone type flow reducing implant  360  ( FIG. 3D ) comprises inner wall  104  and outer wall  102  that curve at front end  106  to form small opening  364 , causing reduction in the entry of blood flow to passage  216 . Alternatively or additionally, inner wall  104  and/or outer wall  102  are tapered to conform for example to coronary sinus  110  as blood flows in direction  116 , optionally changing blood flow dynamics to promote angiogenesis. Alternatively or additionally, front end  106  contacts coronary sinus  110  with a strong pressure and a tapered area  366  contacts coronary sinus  110  with a weak pressure and/or does not contact coronary sinus  110  at least along a portion of outer surface  102 . In this configuration, for example, the stretch of coronary sinus  110  in the restricted area of front edge  106 , may contribute to promoting angiogensis.  
         [0106]     In an exemplary embodiment, dual cone type flow reducing implant  370  ( FIG. 3E ) comprises a sloped area  376  of passage  216  so that front edge  106  comprises the widest diameter of this embodiment of dual cone type flow reducing implant  370 . In an exemplary embodiment, blood pressure builds in flow passage  216  and then is released through opening  364 , creating a thin stream of blood flow with higher pressure than blood entering flow reducing implant  370  in direction  116 . The exiting blood through opening  364  may serve to increase pressure on the valve of coronary sinus  110  that leads into the right atrium. As noted, angiogenesis may be promoted by blood flow changes that affect the valve of the atrium. Alternatively or additionally, a taper along area  376  may be appropriate to conform, for example, to coronary sinus  110  that itself tapers from a wider cross sectional diameter to a narrower cross sectional diameter.  
         [0107]     In an exemplary embodiment of the invention, opening  364  is made very small, for example substantially blocking all blood flow therethrough, such as over 90%, 95% or 98% of such flow being blocked by the reducer. However, an opening  364  may still be useful, for example for mounting on a guide wire. For example, opening  364  may be sized to receive (with a small amount of freedom), a guidewire having a diameter, of, for example, 14/1000 of an inch or smaller, such as 7/1000 of an inch, or larger, such as 20/1000, 30/1000 or 40/1000 of an inch. Alternatively or additionally, a sheath  352  as in  FIG. 3B  is used, except that its aperture  354  is normally closed, but is elastic and allows the passage of a guidewire therethrough. Such an elastic sheath may also be provided on aperture  364 .  
         [0108]     To achieve blood flow that promotes angiogensis, a relatively rapid transition from (wide) pre-implant diameter  112  to narrow passage  114  and return to (wide) post implant diameter  118 , ( FIG. 4 ) may prove to promote angiogenesis, for example, due the change in flow dynamics it creates. A tube type flow reducing implant  400 , in accordance with an exemplary embodiment of the invention, comprises a long wall  406 , a portion of which is surrounded by a ring-shaped tube  420 . Optionally, the diameter of flow passage  114  adjacent a bulge  404  in long wall  406  provides a rapid transition from pre-implant diameter  112  to narrow passage  114  and back to sinus post implant diameter  118 .  
         [0109]     In an exemplary embodiment, tube  420  has an interior space  430  enclosed within a circular wall  402  that is, for example, inflatable using a hose  428 , for example, in a similar fashion to hose  1020  in  FIG. 10 , explained below.  
         [0110]     In an exemplary embodiment, tube  420  inflates so that interior  430  has two or more cross sectional diameters, thereby allowing adjustment of narrow passage  114  to modify the amount of reduction in blood flow and/or other factors of blood flow, for example, change blood stream dynamics.  
         [0111]     Alternatively or additionally, interior  430  contains a material that absorbs liquid, thereby expanding. Following implantation, for example, tube  420  absorbs liquid and interior  430  increases in size until tube  420  reaches its expanded state.  
         [0112]     Alternatively or additionally, wall  402  and/or tube  430  comprise a resilient material, for example Nitinol, and expand to a final state without inflation. Alternatively or additionally, flow reducing implant  400 , and/or embodiments mentioned below, are manufactured from a biocompatible material, comprising, for example, a soft silicone elastomer and/or another soft material such as latex, teflon, gortex, kevlar and/or polyurethane.  
         [0113]     Alternatively or additionally, interior  430  is filled, for example with a spongy material, for example that is different than the material comprising long wall  406  and/or wall  402 . Spongy material of interior  430 , for example remains compressed in a compact size until its exit from catheter  122  whereupon interior  430  expands, causing the expansion of tube  420 .  
         [0114]     In an exemplary embodiment, long wall  406  is contoured and comprises a shape memory material and achieves its final state, including bulge  404 , upon exit from catheter  122 . Alternatively or additionally, long wall  406  is, for example, not contoured and tube  420  presses against long wall  406  to create bulge  404 .  
         [0115]      FIG. 5  is an isometric view of a staved type flow reducing implant  530 , in accordance with an exemplary embodiment of the invention, comprising staves  532 ,  534 ,  536  and  538  around a resilient membrane wall  502 . Resilient membrane wall  502  of staved type flow reducing implant  530  is of a material and a thickness that allow it to readily project into flow passage  216  upon the movement of staves  532 ,  534 ,  536  and  538  toward each other. As flow reducing implant  530  assumes a compact state without, for example, trailing resilient material  502 , staved type flow reducing implant  530  is easily positioned inside catheter  122  ( FIG. 1 ) for removal and/or repositioning in coronary sinus  110 .  
         [0116]     Alternatively or additionally, staved type flow reducing implant  530  is at least partially reduced in diameter by the pressure of the inner surface of coronary sinus  110  as it is moved longitudinally to a new position in coronary sinus  110 , with membrane wall  502 , for example, projecting into flow passage  216 . In an exemplary embodiment, of staves  532 ,  534 ,  536  and  538  and/or resilient material  502  comprise shape memory materials and, after attaining its new position in coronary sinus  110 , flow reducing implant  500  returns to its memorized shape.  
         [0117]     Alternatively or additionally, a balloon catheter is deployed, for example, to cause staved type flow reducing implant  530  to assume is memorized shape after it has reached its new position in coronary sinus  110 .  
         [0118]     In a particular embodiment of the invention, membrane  502  is formed of or coated with a material that enhances adhesion thereto, for example PTFE or a tissue adhesive, at least on its outer surface. In this embodiment, a thin membrane may be used, with the narrowing effect achieved by the collapsing of the vessel on the membrane instead of or in addition to any effect of the thickness of the membrane. Optionally, the staves are pre-stressed so that one or both of their outer ends project radially outwards. Optionally, this pre-stressing assists in anchoring in—and/or collapsing of—the blood vessel. Optionally, the ends of the staves are made rounded, for example in the form of rounded plates, to prevent inadvertent penetration. Alternatively or additionally, the staves are replaced by a stent and/or have stent sections at one or both ends.  
         [0119]      FIG. 6A  is an isometric view of a wire cone type flow reducing implant  630 , in accordance with an exemplary embodiment of the invention, comprising one or more transverse wires  632 ,  634 ,  636  and/or  638  spanning flow passage  216  to reduce blood flow and/or change blood stream dynamics. Wires  632 ,  634 ,  636  and/or  638  may be, for example, joined at a point  642  and may be curved and/or straight in one or more projection planes in relation to wire cone type flow reducing implant  630  to reduce blood flow and/or change blood stream dynamics  
         [0120]     In an exemplary embodiment, elements  632 ,  634 ,  636  and/or  638 , for example, form two continuous wires comprising wire  632  continuous with wire  636  and/or wire  634  continuous with wire  638 . Alternatively, wires  632 ,  634 ,  636  and/or  638  may be separate from each other, but bent so that their tips come close to one another near point  642 . Optionally, wire  632  continuous with wire  636  may be straight. Alternatively or additionally, wire  632  continuous with wire  636  may be bowed, for example, so the bow extends beyond outer wall  102  and/or inside inner wall  104 , thereby influencing blood stream dynamics to initiate and/or increase angiogenesis.  
         [0121]     Alternatively or additionally, as with flaps  232 ,  234  and  236 , wires  632 ,  634 ,  636  and/or  638  are shaped to extend beyond, perpendicular to and/or interior to flow passage  216 . Similarly, wire cone type flow reducing implant  630  may have, for example, an outer wall  102 , inner wall  104  and/or space  430  configured in similar fashion to other embodiments described.  
         [0122]     In laminar blood flow dynamics, the blood that is closest to the inner walls of coronary sinus  110  move more slowly than blood flow passing through the center of coronary sinus  110 . It may be desirable to further slow the blood flow in the center of coronary sinus  110  over that provided by wires  632 ,  634 ,  636  and/or  638 , thereby promoting angiogenesis.  
         [0123]      FIG. 6B  is an isometric view of a plate wire cone type flow reducing implant  640 , in accordance with an exemplary embodiment of the invention, comprising one or more transverse wires  632 ,  634 ,  636  and/or  638  that are joined to a plate  660  spanning flow passage  216 . Plate  660 , for example, is positioned to block blood flow in the center of coronary sinus  110 . Further changes in the configuration of transverse wires  632 ,  634 ,  636  and/or  638 , and/or plate  660 , for example so they are thicker and/or of variable thickness, are contemplated for the purpose of modifying the blood flow pattern to promote angiogenesis.  
         [0124]     In an exemplary embodiment, plate  660  comprises four curves,  652 ,  654 ,  656  and/or  658  to which wires  632 ,  634 ,  636  and/or  638  are joined thereby providing a connection between plate  660  and wires  632 ,  634 ,  636  and/or  638  that reduces turbulence in blood flow. Alternatively or additionally, plate  660  may comprise a passage through its center, for example being round in shape, thereby further modifying the flow pattern of blood through coronary sinus  110 .  
         [0125]      FIG. 6C  is an isometric view of a sphere wire cone type flow reducing implant  650 , in accordance with an exemplary embodiment of the invention, comprising one or more transverse wires  632 ,  634 ,  636  and/or  638  that are joined to a spherical member  674  spanning flow passage  216 . Spherical member  674 , for example, may comprise a variety of sizes and/or shapes such as flat spheroid, ovoid and/or others, depending, for example, on amount of flow reduction required, angiogenesis promotion and/or flow turbulence reduction.  
         [0126]     In an exemplary embodiment, wires  632 ,  634 ,  636  and/or  638  of wire cone type flow reducing implants  630 ,  640  and/or  650 , are resilient so that they automatically bow into their final position shown in their respective figures upon exiting catheter  122  ( FIG. 1 ). Alternatively or additionally, wires  632 ,  634 ,  636  and/or  638  of wire cone type flow reducing implants  630 ,  640  and/or  650 , may comprise flexible materials and/or flexible chains that assume their final shape dependent upon, for example, their drag in the blood flowing around them.  
         [0127]     In an exemplary embodiment, wire cone type flow reducing implants  630 ,  640  and/or  650  may be reduced in size with wires  632 ,  634 ,  636  and/or  638  and/or their attachments, for example spherical member  674 , beyond outside wall  102 . The less material contained between inside walls  104 , for example, allows outer wall  102  to assume a smaller diameter when in a reduced size, thereby facilitating removal and/or repositioning in a portion of the coronary sinus that has a smaller diameter. This is particularly useful when coronary sinus  110  is of a narrow diameter. Alternatively or additionally, spherical member  674  and/or wires  632 ,  634 ,  636  and/or  638  position inside of outside wall  102 , following reduction in size, to prevent possible trauma as they are moved-against the walls of coronary sinus  110 .  
         [0128]     To promote angiogenesis, as noted, it may be necessary to change the configuration of a flow reducing implant  700  and/or another of the other embodiments of flow reducing implant  100  following implantation in coronary sinus  110 . Changes in the configuration of flow reducing implant  700 , for example, may change the blood flow pattern and/or flow volume in coronary sinus  110  to further promote angiogenesis and/or prevent untoward sequella due to improper blood flow turbulence. The necessary changes in the configuration of flow reducing implant  700 , for example, may require delicate manipulation of the various flow reducing implant embodiments.  
         [0129]      FIG. 10  is an isometric view of a balloon catheter  1000  with expansion rods  1030  in accordance with an exemplary embodiment of the invention, that facilitates fine adjustments in the configuration of a flow reducing implant  700  shown in a longitudinal section. In an exemplary embodiment, balloon catheter  1000  comprises a balloon  1010  connected to a hose  1020  that inflates and/or deflates balloon  1010 .  
         [0130]     In an exemplary embodiment, balloon catheter  1000  is used to open and/or modify the shape of type flow reducing implant  700 . For example, balloon catheter  1000  is positioned within a front flare  744  and inflated using inflator hose  1020  thereby expanding its rods  1030  radially outward to exert pressure on front flare  744  to cause its expansion. Following this, balloon catheter  1000  is deflated using inflator hose  1020 .  
         [0131]     In an exemplary embodiment, rods  1030 , for example, are positioned around balloon  1010  that comprises a material of a flexibility and a thickness that allow it to readily reduce in diameter between rods  1030  upon deflation. With balloon  1010  contained between rods  1030 , balloon catheter  1000  easily passes through a narrow passage  742 , into a rear flare  746 .  
         [0132]     With balloon catheter  1000  positioned within rear flare  746 , it is inflated using inflator hose  1020  thereby expanding its rods  1030  radially outward to cause expansion of rear flare  746 . Following this, balloon catheter  1000  is deflated through inflator hose  1020  to pass into narrow passage  742  where it is inflated to cause expansion of passage  742 . Balloon catheter  1000  is then deflated and moved to front flare  744  and inflated to cause expansion of flare  722 . Finally balloon catheter  1000  is deflated and removed from coronary sinus using, for example, a percutaneous catheter removal technique known in the art.  
         [0133]     In an exemplary embodiment of the invention, once flow reducing implant  700  is formed, it is mounted on a jig having the desired final expanded shape and heated so that it naturally attains that shape, for example, when released from catheter  122 . In an exemplary embodiment, narrow passage  742  is manufactured using a different material and/or process than that of flares  744  and/or  746 . For example, flares  744  and/or  736  are woven into a mesh and narrow passage  742  is cut from sheet metal.  
         [0134]     In an exemplary embodiment, flare ends  744  and/or  746  have a diameter of between 2 mm and 30 mm, for example, 5 mm, 10 mm, 15 mm, 20 mm or any larger, smaller or intermediate diameter, for example selected to match the diameter of coronary sinus  110 . Narrow passage  742  diameter may be, for example, 1 mm, 2 mm, 3 mm, 5 mm, 10 mm or any smaller, larger or intermediate diameter, for example selected to achieve desired flow dynamics and/or a pressure differential across flow reducing implant  700 .  
         [0135]     In an exemplary embodiment of the invention, the ratio between the cross-section of narrow passage  742  and flare end  744  and/or flare end  746  is 0.9, 0.8, 0.6, 0.4, 0.2 or any larger, smaller or intermediate ratio, for example selected to achieve desired flow dynamics and/or a pressure differential across flow reducing implant  700 .  
         [0136]     Changing the configuration, for example, of flow reducing implant  700  using, for example, balloon catheter  1000  may be desired, for example, to alter the blood flow volume and/or blood stream dynamics. However, such change involves invasion of the patient&#39;s circulatory system and care must be taken not to disrupt the heart&#39;s blood supply and/or rhythm, particularly in patients with compromise coronary circulation. In an exemplary embodiment, modification of flow reducing implant  700 , in order to expand and/or reduce the size of narrow area  742  and/or flares  744  and/or  746  may be accomplished without invasion of the vasculature.  
         [0137]      FIG. 7  is longitudinal section of flow reducing implant  700 , in accordance with an exemplary embodiment of the invention, comprising one or more shape-conforming elements  720  and/or  722  that can be remotely induced to change their configuration. Remote control of the configuration of elements  720  and/or  722  causes, for example, change in configuration, constriction and/or expansion of narrow passage  742 , and/or flares  744  and  746  without associated hazards of an invasive procedure. As narrow passage  742  and/or flare  744  and/or flare  746  change their configuration, the blood flow dynamics are altered, thereby promoting angiogenesis. Alternatively or additionally, as narrow passage  742  and/or flare  744  and/or flare  746  constrict and/or expand, the blood flow pattern in coronary sinus  110  changes, thereby influencing angiogenesis.  
         [0138]     Shape-conforming elements  720  and/or  722 , for example, are charged so that as they receive impulses from impulses  730  and/or  732 , they change into one or more different geometric shapes and/or configurations. The shapes of elements  720  and/or  722  induced by impulsers  730  and  732  cause changes in the configuration of blood flow reducing implant  700 , thereby influencing angiogensis.  
         [0139]     For example, one or both shape-conforming elements  720  and/or  722  straighten, they exert outward expansion pressure on narrow passage  742 , thereby allowing blood flow therethrough to increase. When one or both shape-conforming elements  720  and/or  722  bend further than depicted in  FIG. 7 , they pull the walls of narrow passage  742  inward, causing passage  742  to narrow, thereby reducing blood flow therethrough.  
         [0140]     Alternatively or additionally, when shape-conforming elements  720  and/or  722  bend or straighten the walls of narrow passage  742  may change its configuration, thereby causing changes in blood stream dynamics and/or pressure of blood flow along flow passage  216  and into coronary sinus  110 , all of which may influence angiogenesis.  
         [0141]     Alternatively or additionally, shape-conforming elements  720  and/or  722  are located exterior to flow reducing implant  700 , for example along outer wall  102 . Alternatively or additionally, other shape-conforming elements  720  and/or  722  may be located along flares  744  and/or  746  to provide additional and/or alternative remote control of flow reducing implant  700 .  
         [0142]     Optionally, impulses provided by impulsers  730  and  732  to induce changes in shape-conforming elements  720  and/or  722  and comprise one or more of: RF, acoustic waves such as ultrasound and/or low frequency sound, heat, electricity, electromagnetic, radiation. Alternatively or additionally, impulsers  730  and  732  mediate a chemical reaction that modifies elements  720  and/or  722 , thereby changing their configuration.  
         [0143]     In an exemplary embodiment, a director  738 , external to the patient, directs impulsers  730  and  732  to provide impulses to shape-conforming elements  720  and/or  722 , thereby causing the changes in geometric shape. Director  738 , for example, directs impulsers  730  and  732  via radio waves from an antenna  758 .  
         [0144]     Alternatively or additionally, elements  720  and/or  722  are sensitive to waves that are propagated external to the patient For example, director  738  provides one or more of: RF, acoustic waves such as ultrasound and/or low frequency sound, heat, electricity, electromagnetic and radiation to influence the configuration of elements  720  and/or  722 .  
         [0145]     In an exemplary embodiment, shape-conforming elements  720  and/or  722  comprise a material with a positive charge, for example positively charged plastic and/or silicone rubber. Alternatively or additionally, shape-conforming elements  720  and/or  722  comprise a negatively charged material.  
         [0146]     Optionally, shape-conforming elements  720  and/or  722  are manufactured from a material comprising charged lithium ions. In an exemplary embodiment, waves cause the charged lithium ions to align, thereby changing the geometry of shape-conforming elements  720  and/or  722  to cause changes in the shape of outer wall  102  and/or inner wall  104 .  
         [0147]     In an exemplary embodiment, the strength and/or length of impulses aid in changing shape-conforming elements  720  and/or  722 . For example, impulsers  730  and  732  provide an electric impulse of between 0.1 volts and 0.5 volts (optionally, 0.1 volts or less or 0.5 volts or more), for a period of 10 msec or longer or 6 msec. or shorter. The factors influencing the impulse chosen, for example, depend upon materials comprising shape-conforming elements  720  and/or  722 , their responsiveness to the impulses and/or the desired changes in their shapes to influence the shape of flow reducing implant  700 .  
         [0148]     Flow reducing implant  700 , with shape-conforming elements  720  and/or  722  allows modification in shape and/or blood flow reduction following implantation of flow reducing implant  700  in coronary sinus  110  without an invasive procedure. Alternatively or additionally, an embodiment of flow reducing implant  700  that assumes its installed shape without for example, the use of balloon catheter  1000  may be desirable. In an exemplary embodiment of the present invention, ripple type flow reducing implant  800  ( FIGS. 8A-8C ) comprises shape memory materials that automatically achieve a final configuration state upon exiting catheter  122 , thereby averting the use of balloon catheter  1000  for initial installation of ripple type flow reducing implant  800 .  
         [0149]     Alternatively or additionally, ripple type flow reducing implant  800  contains preformed rows of ripples  852  and/or  862 . Ripples  852  and/or  862  allow modification in size and/or configuration of ripple type flow reducing implant  800  with a minimal amount of expansion force and/or a minimal amount of time using balloon catheter  1000 . Reduction in time and/or force with balloon catheter  1000 , reduces the risk of untoward sequella, for example, to the patient with compromised vasculature.  
         [0150]      FIG. 8C  is an isometric view of a slit type flow reducing implant  820 , in accordance with an exemplary embodiment of the invention, comprising rows of slits  816 ,  826 ,  836  and  846 .  
         [0151]      FIG. 8A  is a plan layout of ripple type flow reducing implant  800  whose details are somewhat different from that of the slit type reducing implant  820  shown in  FIG. 8C . Ripple type flow reducing implant  800  has a row of ripples  862  and a row of ripples  852 , corresponding to slit rows  862  and  852  respectively in slit type flow reducing implant  820 . Further, for the representation, ripple type flow reducing implant  800  has been cut to separate an edge  810  from an edge  808 , thereby providing its plan view.  
         [0152]     Ripple type flow reducing implant  800  comprises longitudinal rows of slits  816 ,  826 ,  836  and  846 , having lengths of  818 ,  828 ,  838  and  848  respectively. In an exemplary embodiment, rows of slits  816 ,  826 ,  836  and  846 , for example, automatically expand to form installed ripple type flow reducing implant  800  without use of balloon catheter  1000 . Ripple type flow reducing implant  800  comprises an outer surface (not shown) and an inner surface  802  that defines a flow passage  806  that is shaped, for example, in a similar shape as that of flow reducing implant  700 .  
         [0153]     Ripple type flow reducing implant  800 , for example, attains a final shape that is, for example, similar to that of flow reducing implant  700 . This final shape, for example, occurs as its shape memory material expands when released from catheter  122  ( FIG. 1 ). Alternatively or additionally, balloon catheter  1000  may be used to facilitate expansion of ripple type flow reducing implant  800 , for example, when it is made of materials without an automatic shape memory. However, rows of slits  816 ,  826 ,  836  and  846  with their lengths and/or orientation that promote a specific final shape, allow ripple type flow reducing implant  800  to readily form into a final configuration even when not formed of shape memory materials. Therefore, installation of ripple type flow reducing implant  800  optionally occurs with a minimal amount of time and/or expansion force by balloon catheter  1000 .  
         [0154]     In an exemplary embodiment, flow passage  806  corresponds to flow passage  216  in  FIG. 10 , comprising at least two diameters, a small diameter corresponding to slits  846  and a flared diameter corresponding to slits  836 ,  826  and/or  816 .  
         [0155]     In an exemplary embodiment, ripple type flow reducing implant  800  may easily be further modified as it contains two rows of ripples  852  and  862  that, for example, expand flow passage  806  in response to expansion pressure from balloon catheter  1000 . When balloon catheter  1000  is introduced into flow passage  806  and expanded, rows of ripples  852  and/or  862  are induced to straighten, thereby increasing the diameter of flow passage  806  through ripple type flow reducing implant  800 .  
         [0156]     Alternatively or additionally, the apex of each ripple in ripple row  852  face into flow passage  806 , and the apex of each ripple of ripple row  862  face away from flow passage  806 . In an exemplary embodiment, ripple row  852  expands at a first expansion pressure from balloon catheter  1000  as the apex of each ripple of ripple row  852  contact expansion balloon catheter  1000  as it expands against surface  802 .  
         [0157]     In an exemplary embodiment, ripple row  862  expands with application of a second expansion pressure as the apex or each ripple in ripple row  862  does not come in contact with balloon catheter  1000  and hence only pressure of balloon catheter  1000  on flow passage  806  causes their expansion.  
         [0158]     In this embodiment, for example, an initial pressure of between 34 atmospheres (optionally 3 atmospheres or less or 4 atmospheres or more) causes expansion of ripple row  852 . A second pressure, for example, of between 7-8 atmospheres (optionally 7 atmospheres or less or 8 atmospheres or more), causes the expansion of ripple row  862 .  
         [0159]     Alternatively or additionally, the apex of each ripple of ripple row  862  face the same way as the apex of each ripple of ripple row  852  and ripple row  862  comprises a material, material coating and/or material additive that renders it stiffer, for example, than ripple row  852 . As a result of the change in material of ripple row  862 , for example, ripple row  862  does not expand when a lower expansion pressure, sufficient to expand ripple row  852  is applied to flow passage  806 .  
         [0160]     Ripple type flow reducing implant  800 , demonstrates easy implantation without using, for example, balloon catheter  1000  for implantation due to its shape memory. In addition, modification of ripple type flow reducing implant  800  following implantation is easily and/or rapidly accomplished using balloon catheter  1000  that presses against one or more ripple rows  852  and/or  862 .  
         [0161]      FIG. 8B  is an enlarged of the plan layout of ripple type flow reducing implant  800 , in accordance with an exemplary embodiment of the invention. Section A-A comprises a slot  858  with a first radius  864  of 0.2 millimeters and a second radius  866  of 0.2 millimeters though radii  864  and/or  866  could be between 0.1-0.3 millimeters (optionally 0.1 millimeters or smaller or 0.3 millimeters or larger) depending upon, for example, the materials used and/or their flexibility. A distance between radii  864  and  866 , for example, is 1.0 millimeters though it could be between 0.5-2.0 millimeters (optionally 0.5 millimeters or smaller or 2.0 millimeters or larger), depending, for example on the contour of ripple type flow reducing implant  800 .  
         [0162]     Additionally, section A-A comprises a left slot  884  and a right slot  886 . In an exemplary embodiment, left slot  884  has a ripple with a left radius  894  of 0.2 millimeters and right slot  886  has a ripple  896  with a right radius  896  of 0.2 millimeters. Additionally or alternatively, radii  894  and/or  896  could be between 0.1-0.3 millimeters (optionally 0.1 millimeters or smaller or 0.3 millimeters or larger) depending, for example on the materials used and/or their flexibility.  
         [0163]     In an exemplary embodiment of the present invention, a cord type flow reducing implant  900  shown in a plan view in  FIG. 9 , comprises a preformed shape that, like ripple row type flow reducing implant  800 , allows it to easily spring into its installed shape without, for example, use of balloon catheter  1000 . In an exemplary embodiment, one or more edges  910  are joined to one or more edges  908  to form cord type flow reducing implant into a tubular shape with flow passage  806  passing therethrough.  
         [0164]     In its assembled state, cord type flow reducing implant  900  comprises a row of slits  924  through which a cord  954  passes, that is modified with minimal expansion pressure from balloon catheter  1000 .  
         [0165]     In an exemplary embodiment, cord  954  is woven to pass under a lead post  982  and over a trailing post  986  so that cord  954  is woven across cord type flow reducing implant  900 . Alternatively or additionally, cord  954  is expandable and attached to surfaces of slots  924 , for example their surfaces facing flow passage  806  or their opposite (outside) surfaces.  
         [0166]     Alternatively or additionally, cord  954  of cord type flow reducing implant  900  is expandable to allow modification in the shape of cord type flow reducing implant  900 , on one or more additional occasions. Repeated modification of cord type flow reducing implant  900  may be desirable, for example, for the patient with unstable coronary vascular flow.  
         [0167]     In an exemplary embodiment, cord type flow reducing implant  900  automatically assumes is memorized shape upon exiting catheter  122  as slits  926 ,  936  and/or  946  automatically expand. In an exemplary embodiment, cord  954  passes through row of slits  924  and has a thickness that creates a bulge in flow passage  806 , thereby creating a narrowing in flow passage  806  that changes blood flow dynamics, for example.  
         [0168]     In an exemplary embodiment, after cord type flow reducing implant  900  expands to its initial configuration automatically upon exiting catheter  122  and further size modification is required, balloon catheter  1000  is introduced into the interior of cord type flow reducing implant  900 . Balloon catheter  1000  is inflated, for example, between 3-4 atmospheres (optionally, 3 atmospheres or less or 4 atmospheres or more), and causes row  924  to move radially outward against cord  954 . Cord  954  moves radially outward, thereby smoothing the bump that cord  954  causes in flow passage  806  along row of slits  924 , changing the flow dynamics of the blood flow through flow passage  806 .  
         [0169]     In an exemplary embodiment, at least a portion of an edge  910  is detached from at least a portion of an edge  908  so when flow reducing implant  900  forms its expanded shape, for example, at least a portion edge  910  and edge  908  overlap. If further expansion is required, additional expansion force is applied, for example, between 7-8 atmospheres (optionally, 7 atmospheres or less or 8 atmospheres or more) of pressure and cord  954  elongates so that edge  910  draws closer and/or passes edge  908 , allowing cord type flow reducing implant  900  to attain another, expanded, diameter.  
         [0170]     In an exemplary embodiment, cord  954  comprises a plastic material that stretches to two or more lengths, depending upon the expansion pressure that is applied to it. Hence, at a lower pressure, cord  954  expands to a first length, thereby defining a first narrow diameter of cord type flow reducing implant  900 . Subsequently a second expansion pressure is applied and cord  954  attains a second, longer, length, thereby defining a second diameter, wider than the narrow diameter.  
         [0171]     Alternatively or additionally, cord type flow reducing implant  900  includes one or more diameters in which edge  910  and edge  908  are separated by a space, thereby providing an interrupted flow passage surface  802 . Alternatively or additionally, cord  954  severs upon application of, for example, pressure between 9-10 atmospheres (optionally 9 atmospheres or less or 10 atmospheres or more). Upon severing cord  954 , edge  910 , for example, maximally separates from edge  908 , thereby applying unrestricted pressure against coronary sinus  10 . As noted above, increased pressure on coronary sinus  110  may enhance angiogenesis caused by one or more other factors.  
         [0172]     In an exemplary embodiment, cord  954  of flow reducing implant  900  comprises a biocompatible material that dissolves in the environment of coronary sinus  110 , for example, a material comprising galactic acid and/or polygalactic acid and/or other materials with similar properties. In an exemplary embodiment, flow reducing implant  900  is placed in coronary sinus  110  and balloon catheter  1000  is used to expand it so that its outer surface contacts the inside surface of coronary sinus  110 . Over a period of time, for example three days or less or four days or more, cord  954  degrades, depending upon the biodissolvable material comprising cord  954 . Once cord  954  has dissolved, flow reducing implant  900  retains its shape, with its outer surface in contact with the inner surface of coronary sinus  110 .  
         [0173]     With cord  954  dissolved, further expansion of inner diameter of flow reducing implant  900  is accomplished with balloon  1010  at a low atmospheric pressure due to the fact that edge  908  passes edge  910  without the hindrance of cord  954 . Hence, to cause edge  908  to pass edge  910 , expansion force need only overcome the stiffness of the material comprising flow reducing implant  900 . In an exemplary embodiment, a pressure of between 34 atmospheres (optionally 3 atmospheres or less or 4 atmospheres or more), causes expansion of wall the flow passage through flow reducing implant  900 .  
         [0174]     In an exemplary embodiment of the present invention, flow reducing implant  900  comprises cord  954  passing through slits  924  and a cord  964  passing through slots  988 . Alternatively or additionally, flow reducing implant  900  comprises three or more cords  954 ,  964  at either end and a cord  974  passing through slots  926  substantially in the middle of flow reducing implant  900 .  
         [0175]     Cords  954 ,  964  and/or  974  serve to maintain the shape and/or appropriate flow passage diameter following installation. To expand the flow passage through flow reducing implant  900 , balloon catheter  1000  is used to expand and/or sever cords  954 ,  964  and/or  974 . Alternatively or additionally, sever cords  954 ,  964  and/or  974  are biodissolvable, dissolving in the environment of coronary sinus  110 .  
         [0176]     In an exemplary embodiment, when cord type flow reducing implant  900  is configured according to the shape of flow reducing implant  700  ( FIG. 10 ), little or no blood migrates through narrow passage  742 , flare  744  and/or flare  746  to contact the walls of coronary sinus  110 . This, for example, is achieved by the narrow cross-section and/or configuration of slits  936  and/or  946  to limit and/or prevent migration of blood through the walls of narrow passage  742 , flare  744  and/or flare  746 . In an exemplary embodiment, to achieve this limitation of blood migration with adequate expansion of cord type flow reducing implant  900 , slits  938  and/or  948  are increased in number, while the width of slits  926 ,  936  and/or  946  is reduced.  
         [0177]     In a particular example, only the widths of slits  926  are reduced, thereby increasing the amount of material near the center of the implant and making the center more difficult to expand, relative to the flared ends.  
         [0178]     Alternatively or additionally, an elastic coating is provided on the inside and/or outside of flow reducing implant  700 , for example, latex, to prevent flow through openings slits  938  and/or  948 . In an exemplary embodiment of the invention, the coating is a separate, flexible layer, that is attached to flow reducing implant  700  at one or more points (e.g., at narrow passage  742  and/or flare  744  and/or flare  746 ) to prevent tearing of the layer by the expanding flow reducing implant  700 . Alternatively or additionally, the coating is preformed to the shape of the expanded flow reducing implant  700 . Prior to expansion, for example, this coating layer is folded and/or pleated.  
         [0179]     In an exemplary embodiment of the present invention, the material thickness for the walls of flow reducing implant  900  and/or other flow reducing implant embodiments, is 0.15 mm. However thinner or thicker materials may be used dependent upon factors such as strength of materials and/or flow dynamic changes desired.  
         [0180]     In an exemplary embodiment, flow reducing implant  900  is designed to shorten minimally during installation, for example, having a length of 20 mm before installation and about 18.8 mm after installation. Alternatively or additionally, a non-shortening design is used, for example a mesh as in peristaltic stents, such as described in U.S. Pat. No. 5,662,713, the disclosure of which is incorporated herein by reference.  
         [0181]     The length of installed flow reducing implant  900  and other embodiments, for example, is optionally selected to match a physiological size of the target vein (e.g., length and curves) and/or to ensure good contact with vein walls. Exemplary lengths are 5 mm, 12 mm, 24 mm, 35 mm 45 mm and any smaller, intermediate or larger size. Alternatively or additionally, the length of narrow passage  742  ( FIG. 7 ), for example, may be 0.5 mm, 1 mm, 2 mm, 3 mm, 5 mm or any smaller, intermediate or larger length, for example selected to achieve desired flow dynamics.  
         [0182]      FIG. 11  is an isometric view of a spring ballast  1100  and a longitudinal section of a step type flow reducing implant  1180  in accordance with an exemplary embodiment of the invention. Spring ballast  1100  comprises spring rods  1130  that are, for example curved and attached to each other at least one end  1192 . In an exemplary embodiment, spring rods  1130  expand radially outward upon exiting catheter  122 . In an exemplary embodiment, catheter  122  is placed at narrow passage  114  of step type flow reducing implant  1180 . Spring ballast  1100  exits catheter  122 , passes through narrow passage  114  past a rear passage  1156  into coronary sinus  110  with post implant diameter  118 .  
         [0183]     In an exemplary embodiment, spring ballast  1100  is pulled with tethers  1060  in a direction  1062  toward rear passage  1156 . Spring ballast  1100  reduces in size between a wall  1146  surrounding passage  1156  and the radial outward pressure caused by spring rods  1130  on wall  1146 , causes expansion of wall  1146  into its expanded position.  
         [0184]     In an exemplary embodiment, spring ballast  1100  is pulled with tethers  1060  in direction  1062  toward narrow passage  114 . Spring ballast  1100  reduces in size between a wall  1142  surrounding narrow passage  114  and the radial outward pressure caused by spring rods  1130  on wall  1142 , causes expansion of wall  1142  into its expanded position.  
         [0185]     In an exemplary embodiment, spring ballast  1100  is then pulled with tethers  1060  in direction  1062  toward a front passage  1154 . Spring ballast  1100  reduces in size between a wall  1144  surrounding front passage  1154  and the radial outward pressure caused by spring rods  1130  on wall  1144 , causes expansion of wall  1144  into its expanded position.  
         [0186]     In an exemplary embodiment, wall  1142  surrounding narrow passage  114  can be modified to enlarge narrow passage  114 . Optionally, spring ballast  1100  comprises an inflatable material  1112  that inflates using, for example, hose  1020 . In an exemplary embodiment, spring ballast  1100  is positioned in narrow passage  114  so that the diameter of spring rods  1130  is reduced. Spring ballast  1100  is inflated using hose  1020  to a pressure of between 34 atmospheres (optionally 3 atmospheres or less or 4 atmospheres or more), and causes expansion of wall  1142  radially outward, thereby increasing the diameter of narrow passage  114 , thereby increasing blood flow.  
         [0187]     In an exemplary embodiment, wall  1142  responds to expansion pressure. In an exemplary embodiment, if narrow passage  114  requires further expansion, spring ballast  1100  is again positioned in narrow passage  114  and inflated. In an exemplary embodiment, spring ballast  1100  is inflated to a second pressure, for example, of between 7-8 atmospheres (optionally 7 atmospheres of less or 8 atmospheres or more) to cause further expansion of wall  1142 , thereby increasing the diameter of narrow passage  114 .  
         [0188]     Alternatively or additionally, wall  1142  is rigid and expansion pressure caused by inflating spring ballast  1100  causes an increase in the diameter of flow passage  114  and an outward bowing of wall  1142  to press radially outward on coronary sinus  110 . In an exemplary embodiment, the apex of bowing is along wall area  1142 , against coronary sinus  110  and narrow flow passage  114  is thereby widened to allow increased blood flow therethrough.  
         [0189]      FIG. 12  shows step type flow reducing implant  1180  ( FIG. 11 ) during manufacture, in accordance with an exemplary embodiment of the invention. In an exemplary embodiment, step type flow reducing implant  1180  comprises a tubular wall  1202  that is initially of a single thickness throughout defining narrow passage  114  its entire length. In an exemplary embodiment, a boring drill  1210  is bored into wall  1202  to create rear wall  1146  that is narrower than wall  1202  and defines rear passage  1156 .  
         [0190]     In an exemplary embodiment, boring drill  1210  is drilled into wall  1202  along front wall  1144  to create a front passage  1154  ( FIG. 11 ) defining front wall  1144 . Wall  1142 , is then left in an undrilled state to define narrow passage  114 .  
         [0191]     In an exemplary embodiment, wall  1142  may be further drilled to increase the diameter of narrow passage  114 . Alternatively or additionally, wall  1202  comprises a material that responds to two or more expansion pressures. In an exemplary embodiment, spring ballast  1100  is inflated to two or more inflation pressures, as described above, to provide two or more diameters of narrow passage  114 .  
         [0192]     In an exemplary embodiment, boring drill  1210  has a bevel  1212  so that in drilling wall  1142 , it leaves a slanted wall  1222 , allowing a specific pattern of blood flow as it passes through narrow passage  114  that promotes angiogensis and/or decreased turbulence. Alternatively or additionally, wall  1142  adjacent to narrow passage  114 , can be further modified in shape, for example comprising grooves (not shown) along narrow passage  114  to further influence blood flow dynamics that promote angiogenesis.  
         [0193]     It should be appreciated that in a slotted implant, such boring and/or forming may be performed before or after laser (or other cutting) used to form the cut-outs (e.g., as in  FIG. 9 ).  
         [0194]     While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. For example, use of the flow reducing implant  700  is not restricted to application in the coronary sinus, but may be used in other veins, cavities and/or vessels related to circulation where reduction in circulation may promote angiogenesis.  
         [0195]     A variety of values have been utilized to describe the invention including, diameters, lengths and types materials of the various flow reducing implants. Although a variety of values and/or materials have been provided, it should be understood that these could vary even further based upon a variety of engineering principles, materials, intended use and designs incorporated into the invention.  
         [0196]     It should be appreciated that different features may be combined in different ways. In particular, not all the features shown above in a particular embodiment are necessary in every similar exemplary embodiment of the invention. Further, combinations of features from different embodiments into a single embodiment or a single feature are also considered to be within the scope of some exemplary embodiments of the invention. In addition, some of the features of the invention described herein may be adapted for use with prior art devices, in accordance with other exemplary embodiments of the invention. The particular geometric forms and measurements used to illustrate the invention should not be considered limiting the invention in its broadest aspect to only those forms. Although some limitations are described only as method or apparatus limitations, the scope of the invention also includes apparatus designed to carry out the methods and methods of using the apparatus.  
         [0197]     Also within the scope of the invention are surgical kits, for example, kits that include sets of delivery systems and flow reducing implants. Optionally, such kits also include instructions for use. Measurements are provided to serve only as exemplary measurements for particular cases, the exact measurements applied will vary depending on the application. When used in the disclosure and/or claims, the terms “comprises”, “comprising”, “includes”, “including” or the like means “including but not limited to”.  
         [0198]     It will be appreciated by a person skilled in the art that the present invention is not limited by what has thus far been described. Rather, the scope of the present invention is limited only by the following claims.