Patent Publication Number: US-2017348004-A1

Title: Methods, systems and devices for treating orthostatic intolerance

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/US2014/068667, (Attorney Docket No. 29919-713.601), filed Dec. 4, 2014, which claims priority to U.S. Provisional Application No. 61/912,848 (Attorney Docket No. 29919-713.101), filed Dec. 6, 2013, the entire contents of which are incorporated herein by reference. 
     This application is related to, but does not claim priority to, the following applications: U.S. Pat. No. 7,828,814, entitled “Device and Method for Establishing an Artificial Arterio-Venous Fistula”, filed Apr. 4, 2007; U.S. Pat. No. 8,641,747, entitled “Devices for Arterio-Venous Fistula Creation”, filed Jun. 13, 2005; U.S. Pat. No. 8,016,782, entitled “Methods for Providing Oxygenated blood to Venous Circulation”, filed Jun. 13, 2005; U.S. Pat. No. 8,641,724, entitled “Devices, Systems, and Methods for Creation of a Peripherally Located Fistula”, filed Nov. 28, 2007; U.S. Pat. No. 8,382,697, entitled “Devices, Systems, and Methods for Peripheral Arteriovenous Fistula Creation”, filed Jan. 22, 2008; U.S. Non-Provisional application Ser. No. 12/752,397, entitled “Device and Method for Establishing an Artificial Arteriovenous Fistula”, filed Apr. 1, 2010; U.S. Non-Provisional Application Ser. No. 12/905,412, entitled “Devices, Systems, and Methods for Enhanced Visualization of the Anatomy of a Patient”, filed Oct. 15, 2010; and International PCT Application Serial Number PCT/US2013/062458, entitled Methods, Systems and Devices for Treating Hypertension”, filed Sep. 27, 2013; each of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The embodiments disclosed herein relate generally to systems, devices and methods for treating a patient, particularly a patient afflicted with orthostatic intolerance. 
     BACKGROUND 
     Orthostatic intolerance (OI) is a condition that afflicts both adults and children. Symptoms include lightheadedness, dizziness, nausea, fatigue, tremors, breathing or swallowing difficulties, headache, visual disturbances, sweating and pallor. Many patients develop swollen, bluish legs, providing evidence of blood pooling in the lower part of the body. These symptoms can become worse or be provoked more quickly in warm temperatures or hot indoor environments like saunas. 
     There are numerous types of OI, such as orthostatic hypotension (OH), orthostatic hypotension with hypertension, and postural orthostatic tachycardia syndrome (POTS). OI has been associated with chronic fatigue syndrome (CFS). 
     Current treatments for OI include non-medical interventions, such as increasing fluids and salt, tilting the head of the bed up a few degrees, wearing compression garments (such as support hose, girdles or abdominal binders), and learning to avoid and cope with things that can make OI worse (such as standing in long lines, being in warm environments and eating large, heavy meals). Pharmaceutical treatments are available but have resulted in suboptimal results in many patients. 
     Current OI treatment methods are associated with incomplete or otherwise limited treatment; high cost; and numerous undesirable side effects. There is therefore a need for improved approaches, including both devices and methods, for treating patients suffering from orthostatic intolerance. 
     SUMMARY 
     According to one aspect of the technology, a method of treating orthostatic intolerance in a patient comprises selecting a patient exhibiting orthostatic intolerance and creating a flow pathway between a first vascular location and a second vascular location. The first vascular location can comprise a source of arterial blood and the second vascular location can comprise a source of venous blood. The method can be constructed and arranged to treat orthostatic intolerance. 
     In some embodiments, the method can be constructed and arranged to decrease orthostatic intolerance in a patient. 
     In some embodiments, the method can be constructed and arranged to eliminate orthostatic intolerance in a patient. 
     In some embodiments, the method can be constructed and arranged to treat a disease or disorder selected from the group consisting of: orthostatic hypotension; orthostatic hypotension with hypertension; postural orthostatic tachycardia syndrome; and combinations thereof. 
     In some embodiments, the method can be further constructed and arranged to increase the flow of blood to the right side of the heart. The increased flow of blood to the right side of the heart can increase cardiac output. 
     In some embodiments, the method can be further constructed and arranged to increase cardiac output. 
     In some embodiments, the method can be further constructed and arranged to reduce arterial hypertension. 
     In some embodiments, the method can be further constructed and arranged to treat a patient disease or disorder selected from the group consisting of: hypertension; arterial hypertension; chronic obstructive pulmonary disease; congestive heart failure; lung fibrosis; adult respiratory distress syndrome; lymphangioleiomyomatosis; pulmonary hypertension; sleep apnea such as sleep apnea due to hypoxemia or hypertension; and combinations thereof. 
     In some embodiments, the method can be further constructed and arranged to cause a physiologic change in the patient selected from the group consisting of: increased oxygen delivery by the arterial system; increased blood volume; increased proportion of blood flow to the descending aorta; increased blood flow to the kidneys; increased blood flow outside the kidneys; increased cardiac output; and combinations thereof. 
     In some embodiments, creating the flow pathway comprises a procedure selected from the group consisting of: dilating tissue proximate the flow pathway with a balloon; applying energy to tissue proximate the flow pathway such as RF energy applied to tissue; and combinations thereof. 
     In some embodiments, the flow pathway comprises a fistula. 
     In some embodiments, the flow pathway comprises a flow rate of at least 400 ml/min. The flow pathway can comprise a flow rate of less than or equal to 1500 ml/min. 
     In some embodiments, the flow pathway comprises a flow rate of less than or equal to 1500 ml/min. 
     In some embodiments, the first vascular location comprises an iliac artery. The second vascular location can comprise an iliac vein. 
     In some embodiments, the first vascular location comprises an artery selected from the group consisting of: aorta; axillary; brachial; ulnar; radial; profundal; femoral; iliac; popliteal; and carotid. The second vascular location can comprise a vein. 
     In some embodiments, the second vascular location comprises a vein selected from the group consisting of: inferior vena cava; saphenous; femoral; iliac; popliteal; brachial; basilic; cephalic; medial forearm; medial cubital; axillary; and jugular. The first vascular location can comprise an artery. 
     In some embodiments, the first vascular location comprises a chamber of the heart. The first vascular location can comprise the left atrium and the second vascular location can comprise the right atrium. The first vascular location can comprise the left ventricle and the second vascular location can comprise the coronary sinus. 
     In some embodiments, the first vascular location comprises the aorta and the second vascular location can comprise a vein, and the flow pathway can comprise a graft positioned between the aorta and the vein. 
     In some embodiments, the flow pathway comprises a diameter of at least 2.5 mm. The flow pathway can comprise a diameter of at least 3.0 mm. The flow pathway can comprise a diameter of less than or equal to 6.0 mm. The flow pathway can comprise a diameter of less than 5.0 mm. 
     In some embodiments, the flow pathway comprises a diameter based on a patient parameter. The patient parameter can comprise a parameter determined prior to the creation of the flow pathway. The patient parameter can comprise a parameter determined during the flow pathway creation procedure. The patient parameter can comprise a parameter measured after the creation of the flow pathway, and the method can further comprise modifying the flow pathway diameter based on the measured patient parameter. The patient parameter can comprise a parameter selected from the group consisting of: cardiac output; blood pressure; flow rate; tilt table test result; ankle brachial index test result; venous insufficiency level; peripheral vascular resistance; shunt flow; pulmonary capillary wedge pressure; right atrial pressure; pulmonary pressure; left atrial pressure; arterial oxygenation; venous oxygenation; and combinations thereof. 
     In some embodiments, the method further comprises creating a second flow pathway between a third vascular location and a fourth vascular location. The second flow pathway can comprise a fistula. The second flow pathway can be created at least twenty four hours after the creation of the first flow pathway. The first vascular location can comprise an artery and the third vascular location can comprise the same artery. The second vascular location can comprise a vein and the fourth vascular location can comprise the same vein. The first vascular location can comprise the iliac artery in the right leg of the patient and the third vascular location can comprise the iliac artery in the left leg of the patient. The cumulative flow rate of the first flow pathway and the second flow pathway can comprise a flow rate of at least 400 ml/min. The cumulative flow rate of the first flow pathway and the second flow pathway can comprise a flow rate of less than or equal to 1500 ml/min. The method can further comprise creating multiple flow pathways comprising at least a third flow pathway. The cumulative flow rate of the multiple flow pathways can comprise a flow rate of at least 400 ml/min. The cumulative flow rate of the multiple flow pathways can comprise a flow rate of less than or equal to 1500 ml/min. 
     In some embodiments, the method further comprises placing an implant proximate the flow pathway. The implant can comprise an anastomotic clip placed between the first flow vascular location and the second vascular location. The implant can comprise a component selected from the group consisting of: anastomotic clip; suture; staple; adhesive; and combinations thereof. The implant can comprise at least a biodegradable portion. 
     In some embodiments, the method further comprises dilating the flow pathway. The dilating the flow pathway can comprise dilating the flow pathway by inflating a balloon in the flow pathway. 
     In some embodiments, the method further comprises modifying the flow pathway. The modifying the flow pathway can comprise dilating at least a portion of the flow pathway. The method can further comprise placing an anastomotic clip in the flow pathway, and the modifying the flow pathway can be performed after placement of the anastomotic clip. The modifying the flow pathway can comprise delivering energy to the flow pathway. The energy delivered can comprise radiofrequency energy. The modifying the flow pathway can be performed at least 24 hours after the creating of the flow pathway. The modifying the flow pathway can comprise modifying a flow pathway parameter selected from the group consisting of: flow pathway cross sectional diameter; flow pathway average cross sectional diameter; flow pathway flow rate; flow pathway average flow rate; diastolic pressure after flow pathway creation; diastolic pressure change after flow pathway creation; systolic pressure after flow pathway creation; systolic pressure change after flow pathway creation; ratio of diastolic to systolic pressure after flow pathway creation; difference between diastolic pressure and systolic pressure after flow pathway creation; and combinations thereof. The modifying the flow pathway can be constructed and arranged to perform a function selected from the group consisting of: increasing flow through the flow pathway; decreasing flow through the flow pathway; increasing the diameter of at least a segment of the flow pathway; decreasing the diameter of at least a segment of the flow pathway; removing tissue proximate the flow pathway; blocking a sidebranch proximate the flow pathway; and combinations thereof. 
     In some embodiments, the method further comprises performing a flow pathway assessment procedure. The flow pathway assessment procedure can comprise an anatomical measurement procedure. The anatomical measurement procedure can comprise measuring an anatomical feature selected from the group consisting of: a flow pathway diameter measurement; a flow pathway length measurement; a measurement of the distance between an artery and vein comprising the flow pathway; a measurement of the distance between the flow pathway and a vessel sidebranch; and combinations thereof. The flow pathway assessment procedure can comprise measuring flow at least one of within or proximate the flow pathway. The flow pathway assessment procedure can comprise measuring a flow selected from the group consisting of: flow through the flow pathway; flow in a vessel segment proximate the flow pathway; flow measured using Doppler Ultrasound; flow measured using angiographic techniques; and combinations thereof. The flow pathway assessment procedure can comprise an assessment of a patient physiologic condition. The patient physiologic condition can comprise a condition selected from the group consisting of: orthostatic intolerance level; dizziness level; lightheadedness level; syncope events; nausea level; fatigue level; tremor state; breathing state; swallowing ability; headache level; visual disturbance level; sweating level; pallor state; cardiac output; blood pressure such as systolic and/or diastolic blood pressure; respiration; a blood gas parameter; blood flow such as blood flow through a vein or artery within and/or proximate the right side of the heart; vascular resistance; pulmonary resistance; average clotting time assessment; serum creatinine level assessment; and combinations thereof. 
     According to another aspect of the invention, a system for treating orthostatic intolerance in a patient comprises a needle delivery device and a flow creation device. The needle delivery device can be constructed and arranged to place a vessel-to-vessel guidewire from a starting vessel to a target vessel. The flow creation device can be constructed and arranged to be advanced over the vessel-to-vessel guidewire and to create a flow pathway between the starting vessel and the target vessel. The system can be constructed and arranged to treat orthostatic intolerance. 
     In some embodiments, the needle delivery device comprises an advanceable needle. 
     In some embodiments, the needle delivery device comprises a needle with a gauge between 20 and 24. The needle can comprise an approximately 22 gauge needle. 
     In some embodiments, the needle delivery device comprises a curved needle. The needle delivery device can further comprise a marker indicating the direction of curvature of the curved needle. The marker can comprise a marker selected from the group consisting of: flat surface, visible marker, line, textured surface, and combinations thereof. The needle delivery device can further comprise a sheath constructed and arranged to slidingly receive the curved needle. The needle can comprise a proximal end and a hub positioned on said proximal end. The hub can be constructed and arranged to be advanced to advance the curved needle out of the sheath. 
     In some embodiments, the needle delivery device comprises a needle comprising a shaped memory alloy. The shaped memory alloy can comprise nickel titanium alloy. 
     In some embodiments, the system further comprises a vessel-to-vessel guidewire constructed and arranged to be placed from the starting vessel to the target vessel by the needle delivery device. The vessel-to-vessel guidewire can comprise a wire with an outer diameter approximating 0.018″. The vessel-to-vessel guidewire can comprise a marker. The marker can be positioned to indicate the flow pathway location. The vessel-to-vessel guidewire can comprise a distal portion and a mid portion and the mid portion can comprise a construction different than the construction of the distal portion. The mid portion can comprise a stiffness greater than the stiffness of the distal portion. 
     In some embodiments, the flow creation device comprises a balloon catheter configured to dilate tissue positioned between the first vascular location and the second vascular location. 
     In some embodiments, the flow creation device comprises an energy delivery device constructed and arranged to deliver energy to tissue positioned between the first vascular location and the second vascular location. 
     In some embodiments, the flow creation device comprises a clip deployment catheter comprising an anastomotic clip. The clip deployment catheter can comprise a handle and the handle can comprise a control constructed and arranged to deploy the anastomotic clip. The control can comprise a button. The handle can comprise a safety position for the control. The handle can comprise a longitudinal axis and the control can be constructed and arranged to be moved relatively perpendicular to said longitudinal axis to transition from the safety position to a first ready to deploy position. The clip can comprise at least two distal arms, and the handle can be constructed and arranged to allow an operator to move the control from a first ready to deploy position to a first deployed position, and the movement can cause the at least two distal arms to be deployed. The handle can comprise a longitudinal axis and the control can be moved relatively parallel to said longitudinal axis to transition from the first ready to deploy position to the first deployed position. The handle can be constructed and arranged to allow an operator to move the control from the first deployed position to a second ready to deploy position. The control can be moved relatively perpendicular to the longitudinal axis to transition from the first deployed position to the second ready to deploy position. The clip can comprise at least two proximal arms, and the handle can be constructed and arranged to allow an operator to move the control from the second ready to deploy position to a second deployed position, and the movement can cause the at least two proximal arms to be deployed. The control can be moved relatively parallel to said longitudinal axis to transition from the second ready to deploy position to the second deployed position. The clip deployment catheter can comprise an outer sheath and the control can be constructed and arranged to be moved from a first position to a second position to cause movement of the outer sheath. The clip deployment catheter can be constructed and arranged such that movement of the control to the second position causes a tactile feedback event to occur. The clip can comprise multiple deployable arms, and the clip deployment catheter can be constructed and arranged such that movement of the control to the second position causes at least one arm to be deployed. The at least one of the clip deployment catheter or the clip can comprise at least one marker constructed and arranged to rotationally position the clip. The marker can be constructed and arranged to be oriented toward the target vessel prior to deployment of the clip. The marker can be oriented based on a patient image. The patient image can comprise a real-time fluoroscopy image. The clip can comprise a swing arm for deployment in the target vessel and the marker can be positioned in alignment with the swing arm. The marker can be positioned on the clip. The clip deployment catheter can comprise a distal portion and said distal portion can comprise the clip and the marker. The marker can be positioned proximate the clip. The clip deployment catheter can comprise a proximal portion and said proximal portion can comprise the marker. The clip deployment catheter can comprise a handle and the marker can be positioned on the handle. The at least one of the clip deployment catheter or the clip can comprise at least one marker constructed and arranged to longitudinally position the clip at the flow pathway location. The marker can indicate the distal end of the clip. The marker can indicate the proximal end of the clip. The clip can comprise multiple deployable arms, and the clip deployment catheter can be constructed and arranged to deploy at least one of said deployable arms and subsequently recapture said one of said deployable arms. The clip deployment catheter can be constructed and arranged to be rotated and simultaneously deployed from the starting vessel to the target vessel over the vessel-to-vessel guidewire. The clip deployment catheter can comprise a projection constructed and arranged to mechanically engage the clip. The projection can comprise a pin. The clip deployment catheter can further comprise a second projection constructed and arranged to mechanically engage the clip. 
     In some embodiments, the system further comprises a flow pathway maintaining implant. The flow pathway maintaining implant can comprise an anastomotic clip. The clip can comprise a plurality of distal arms and a plurality of proximal arms and the distal arms can be independently deployable from the proximal arms. The clip can comprise four deployable distal arms. The clip can comprise four deployable proximal arms. The clip can comprise nickel titanium alloy. The clip can comprise multiple deployable arms and at least two arms can comprise a marker. The marker comprises a radiopaque marker. The flow pathway maintaining implant can comprise suture. The flow pathway maintaining implant can comprise one or more staples. The flow pathway maintaining implant can comprise adhesive. The flow pathway maintaining implant can comprise at least a portion that can comprise biodegradable material. 
     In some embodiments, the system further comprises a venous system introducer. The venous system introducer can be constructed and arranged to access the starting vessel. The venous system introducer can comprise an 11 French introducer. The venous system introducer can comprise a beveled distal tip. The beveled distal tip can comprise an angle between 20° and 50°. The beveled distal tip can comprise an angle of approximately 30°. The venous system introducer can comprise a marker proximate the beveled distal tip. The marker can comprise a radiopaque marker. The venous system introducer can comprise a proximal portion comprising a marker, and the marker can be aligned with the beveled distal tip. The venous system introducer can comprise a distal portion and an expandable element mounted to the distal portion. The expandable element can comprise a balloon. The expandable element can be constructed and arranged to prevent inadvertent advancement of the introducer into the target vessel. The venous system introducer can be constructed and arranged to stabilize the starting vessel. 
     In some embodiments, the system further comprises an arterial system introducer. The arterial system introducer can be constructed and arranged to access the target vessel. The arterial system introducer can comprise a 4 French introducer. 
     In some embodiments, the system further comprises a target wire constructed and arranged for positioning in the target vessel. The target wire can comprise a helical distal portion. The target wire can comprise a radiopaque distal portion. 
     In some embodiments, the system further comprises a flow pathway modifying device. The flow pathway modifying device can comprise an expandable element. The expandable element can be constructed and arranged to expand to a diameter between 3 mm and 5 mm. The expandable element can be constructed and arranged to expand to a diameter of approximately 4 mm. The expandable element can comprise a balloon. The expandable element can comprise at least one of an expandable cage or radially deployable arms. The flow modifying device can comprise a device selected from the group consisting of: an over the wire device constructed and arranged to be delivered over a vessel-to-vessel guidewire as described herein; an expanding scaffold configured to increase or otherwise modify flow pathway geometry such as an expandable balloon; an energy delivery catheter such as a catheter configured to deliver energy to tissue proximate a flow pathway; an agent delivery catheter such as a catheter configured to deliver an agent such as a pharmaceutical agent or an adhesive such as fibrin glue; and combinations thereof. 
     In some embodiments, the system further comprises a patient imaging apparatus. The patient imaging apparatus can comprise a fluoroscope. The patient imaging apparatus can comprise an ultrasound imager. 
     In some embodiments, the system is further constructed and arranged to treat a patient disease or disorder selected from the group consisting of: chronic obstructive pulmonary disease; congestive heart failure; lung fibrosis; adult respiratory distress syndrome; lymphangioleiomyomatosis; pulmonary hypertension; sleep apnea such as sleep apnea due to hypoxemia or hypertension; and combinations thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the present inventive concepts, and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a flow chart of a method for treating a patient by creating a flow pathway between a first vascular location and a second vascular location, consistent with the present inventive concepts. 
         FIG. 2  is a schematic view of a system for creating a flow pathway in a patient, consistent with the present inventive concepts. 
         FIGS. 3A through 3D  are a set of steps for implanting an anastomotic clip, consistent with the present inventive concepts. 
         FIG. 4  is a flow chart of a method for treating a patient with a flow pathway, consistent with the present inventive concepts. 
         FIG. 5  is an angiographic view of a patient&#39;s vein and artery prior to advancement of a needle into the artery, consistent with the present inventive concepts. 
         FIGS. 5A, 5B and 5C  are anatomical views of three different needle trajectory paths, consistent with the present inventive concepts. 
         FIG. 6  is a perspective view of an anastomotic clip, consistent with the present inventive concepts. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Reference will now be made in detail to the present embodiments of the inventive concepts, examples of which are illustrated in the accompanying drawings. Wherever practical, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the inventive concepts. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It will be further understood that the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that, although the terms first, second, third etc. may be used herein to describe various limitations, elements, components, regions, layers and/or sections, these limitations, elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one limitation, element, component, region, layer or section from another limitation, element, component, region, layer or section. Thus, a first limitation, element, component, region, layer or section discussed below could be termed a second limitation, element, component, region, layer or section without departing from the teachings of the present application. 
     It will be further understood that when an element is referred to as being “on” or “connected” or “coupled” to another element, it can be directly on or above, or connected or coupled to, the other element or intervening elements can be present. In contrast, when an element is referred to as being “directly on” or “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). When an element is referred to herein as being “over” another element, it can be over or under the other element, and either directly coupled to the other element, or intervening elements may be present, or the elements may be spaced apart by a void or gap. 
     The term “and/or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example “A and/or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein. 
     The term “diameter” where used herein to describe a non-circular geometry is to be taken as the diameter of a hypothetical circle approximating the geometry being described. For example, when describing a cross section, such as the cross section of a component, the term “diameter” shall be taken to represent the diameter of a hypothetical circle with the same cross sectional area as the cross section of the component being described. 
     Referring now to  FIG. 1 , a flow chart for selecting and treating a patient by creating at least one fistula or other flow pathway between a first vascular location in the patient&#39;s arterial system and a second vascular location in the patient&#39;s venous system is illustrated, consistent with the present inventive concepts. In STEP  10 , a patient assessment is performed, such as to diagnose the patient and determine if one or more flow pathways (hereinafter “flow pathway” for a single flow pathway or multiple flow pathways) should be created in the patient. A patient can be selected based on a disease or disorder which is diagnosed in STEP  10  or previously. In some embodiments, a patient diagnosed with orthostatic intolerance is selected to receive a flow pathway. The flow pathway can be created to eliminate or at least decrease orthostatic intolerance in a patient. The patient can exhibit a form of orthostatic intolerance selected from the group consisting of: orthostatic hypotension; orthostatic hypotension with hypertension; postural orthostatic tachycardia syndrome; and combinations of these. Alternatively or additionally, a patient selected to receive a flow pathway can be afflicted with a disease or disorder selected from the group consisting of: hypertension; arterial hypertension; chronic obstructive pulmonary disease (COPD); congestive heart failure; lung fibrosis; adult respiratory distress syndrome; lymphangioleiomyomatosis; pulmonary hypertension; sleep apnea such as sleep apnea due to hypoxemia or hypertension; and combinations of these. The flow pathway can be created to reduce arterial hypertension of the patient. The flow pathway can be created to increase cardiac output of the patient. The flow pathway can be created to increase the flow of blood to the right side of the heart, such as to increase cardiac output of the patient. The flow pathway can be created to cause a physiologic change in the patient selected from the group consisting of: increased oxygen delivery by the arterial system; increased blood volume; increased proportion of blood flow to the descending aorta; increased blood flow to the kidneys; increased blood flow outside the kidneys; increased cardiac output; and combinations of these. 
     In STEP  20 , a flow pathway creation procedure is performed on the patient. In some embodiments, the flow pathway creation procedure is performed as described in reference to  FIG. 4  herebelow. In some embodiments, the flow pathway creation procedure is performed using a system of devices and components similar to system  100  of  FIG. 2  described herebelow. The flow pathway is created between a first vascular location in the arterial system, such as an artery, and a second vascular location in the venous system, such as a vein. The flow pathway creation procedure can comprise a clinical procedure selected from the group consisting of: a surgical procedure such as a surgical procedure performed in an operating room; an interventional procedure such as an interventional procedure performed in a catheterization lab or radiology lab; and combinations of these. The flow pathway creation procedure can include the placement of a vessel-to-vessel guidewire between a starting vessel such as a vein (e.g. an iliac vein), and a target vessel such as an artery (e.g. an iliac artery). In these embodiments, the flow pathway can be created using one or more flow pathway creation devices that are advanced over the vessel-to-vessel guidewire. An anastomotic clip or other implant can be placed into the flow pathway via a clip placement device advanced over the vessel-to-vessel guidewire. Alternatively, a flow pathway can be created without an anastomotic clip, such as through placement of suture and/or staples (e.g. in an open surgery or via an over-the-wire suture and/or staple delivery device). One or more implants placed within and/or proximate the flow pathway can be biodegradable or comprise one or more biodegradable portions. In some embodiments, a tissue treatment procedure can be performed to create the flow pathway (e.g. with or without an implant) such as a procedure using energy (e.g. radiofrequency energy) or an adhesive (e.g. fibrin glue) coating applied to the tissue surrounding or otherwise proximate the flow pathway. One or more flow pathway treatment or modification procedures can be performed using flow pathway treatment or modification devices advanced over the vessel-to-vessel guidewire, such as the flow pathway modification procedure performed in STEP  40  herebelow. 
     In some embodiments, at least one fistula or other flow pathway is created between an artery and a vein at a location distal to the renal arteries (i.e. at an infrarenal location such as a flow infrarenal flow pathway created between an iliac artery and an iliac vein). In some embodiments, a flow pathway is created proximate a kidney. Numerous locations for the fistula or other flow pathway can be selected, such as a flow pathway located between an artery and vein as described in reference to  FIG. 4  herebelow. Alternatively or additionally, a flow pathway can be created between a chamber of the heart and a second vascular location, such as between the left atrium and the right atrium or between the left ventricle and the heart&#39;s coronary sinus. Alternatively or additionally, arterial blood can be diverted to the venous system by way of a flow pathway comprising a bypass graft, such as is described in applicant&#39;s U.S. Pat. No. 8,016,782, entitled “Methods for Providing Oxygenated Blood to Venous Circulation”, filed Jun. 13, 2005, the contents of which are incorporated by reference herein in its entirety. 
     During the flow pathway creation procedure and/or in a subsequent flow pathway modification procedure, a flow pathway dilation procedure can be performed in which tissue within and/or proximate the flow pathway is dilated with a balloon catheter. In some embodiments, an anastomotic clip is placed in the flow pathway and a balloon catheter is used to dilate the flow pathway and anastomotic clip simultaneously. In some embodiments, the dilating balloon comprises a diameter of approximately 3 mm to 6 mm, such as a diameter of approximately 4 mm or a diameter of approximately 5 mm. In some embodiments, a single flow pathway is created to treat the patient, and the flow pathway flow rate comprises a flow rate of at least 400 ml/min and or no more than 1500 ml/min, such as a flow rate of at least 600 ml/min and/or no more than 1000 ml/min. In other embodiments, multiple flow pathways are created to treat the patient (e.g. in one or more clinical procedures), and the cumulative flow rate through the multiple flow pathways comprises a flow rate of at least 400 ml/min and/or no more than 1500 ml/min. 
     In STEP  30 , a flow pathway assessment procedure can be performed. STEP  30  can be performed in the same clinical procedure as STEP  20 , and/or in a subsequent clinical procedure such as a procedure at least twenty-four hours after completion of STEP  20 , or at least 1 week, at least 1 month, and/or at least 6 months after completion of STEP  20 . In some embodiments, the assessment performed in STEP  30  includes one or more anatomical measurements, such as a measurement selected from the group consisting of: a flow pathway diameter measurement; a flow pathway length measurement; a measurement of the distance between an artery and vein comprising the flow pathway; a measurement of the distance between the flow pathway and a vessel sidebranch; and combinations of these. In some embodiments, the assessment performed in STEP  30  comprises an assessment of flow (e.g. flow within and/or proximate the flow pathway), such as a flow assessment selected from the group consisting of: flow through the flow pathway; flow in a vessel segment proximate the flow pathway; flow measured using Doppler Ultrasound; flow measured using angiographic techniques; and combinations of these. In some embodiments, the assessment performed in STEP  30  comprises an assessment of a patient physiologic condition, such as an assessment of a physiologic condition selected from the group consisting of: orthostatic intolerance level; dizziness level; lightheadedness level; syncope events; nausea level; fatigue level; tremor state; breathing state; swallowing ability; headache level; visual disturbance level; sweating level; pallor state; cardiac output; blood pressure such as systolic and/or diastolic blood pressure; respiration; a blood gas parameter; blood flow such as blood flow through a vein or artery within and/or proximate the right side of the heart; vascular resistance; pulmonary resistance; average clotting time assessment; serum creatinine level assessment; and combinations of these. 
     In STEP  40 , one or more flow pathway parameters can be modified. STEP  40  can be performed in the same clinical procedure as STEP  20 , and/or in a subsequent clinical procedure such as a procedure at least twenty-four hours after completion of STEP  20 , or at least 1 week, at least 1 month, and/or at least 6 months after completion of STEP  20 . In some embodiments, STEP  30  and STEP  40  are performed in the same clinical procedure (e.g. both in the same clinical procedure as STEP  20  or both in a subsequent clinical procedure). In some embodiments, one or more patient or flow pathway parameters to be modified are selected from the group consisting of: flow pathway cross sectional diameter; flow pathway average cross sectional diameter; flow pathway flow rate; flow pathway average flow rate; diastolic pressure after flow pathway creation; diastolic pressure change after flow pathway creation (e.g. as compared to diastolic pressure prior to flow pathway creation); systolic pressure after flow pathway creation; systolic pressure change after flow pathway creation (e.g. as compared to systolic pressure prior to flow pathway creation); ratio of diastolic to systolic pressure after flow pathway creation; difference between diastolic pressure and systolic pressure after flow pathway creation; and combinations of these. 
     Flow pathway modification procedures can include but are not limited to: increasing flow through the flow pathway; decreasing flow through the flow pathway; increasing the diameter of at least a segment of the flow pathway; decreasing the diameter of at least a segment of the flow pathway; removing tissue proximate the flow pathway; blocking a sidebranch proximate the flow pathway; and combinations of these. A flow pathway modifying device can include one or more devices selected from the group consisting of: an over the wire device constructed and arranged to be delivered over a vessel-to-vessel guidewire as described herein; an expanding scaffold configured to increase or otherwise modify flow pathway geometry such as an expandable balloon; an energy delivery catheter such as a catheter configured to deliver energy to tissue proximate a flow pathway; an agent delivery catheter such as a catheter configured to deliver an agent such as a pharmaceutical agent or an adhesive such as fibrin glue; and combinations of these. 
     In some embodiments, the flow pathway comprises a diameter of at least 2.5 mm, such as a diameter of at least 3.0 mm. In some embodiments, the flow pathway comprises a diameter of no more than 5.0 mm, such as a diameter of no more than 4.0 mm. In some embodiments, the flow pathway comprises a diameter and/or a target flow rate that is based on a patient parameter, such as a measured patient parameter. The patient parameter can be determined prior to the creation of the flow pathway, during creation of the flow pathway and/or after the creation of the flow pathway (e.g. when the flow pathway is modified based on the patient parameter). In these embodiments, the patient parameter on which the flow pathway diameter and/or target flow rate is based can comprise a parameter selected from the group consisting of: cardiac output; blood pressure; flow rate; tilt table test result; ankle brachial index test result; venous insufficiency level; peripheral vascular resistance; shunt flow; pulmonary capillary wedge pressure; right atrial pressure; pulmonary pressure; left atrial pressure; arterial oxygenation; venous oxygenation; and combinations thereof. 
     In some embodiments, a second fistula or second flow pathway is created, such as using the techniques of STEP  20  described hereabove. The second flow pathway can be created in the same clinical procedure as STEP  20  (in which the first flow pathway is created), or in a subsequent clinical procedure such as a procedure performed at least twenty-four hours after completion of STEP  20 , or at least 1 week, at least 1 month, and/or at least 6 months after completion of STEP  20 . A second flow pathway can be created due to inadequate therapy provided by the first flow pathway, and/or if the first flow pathway has insufficient flow (e.g. becomes non-patent). A second flow pathway can be created due to formation of a vascular (e.g. venous) stenosis proximate the first flow pathway. In these embodiments, the first flow pathway can be reversed (e.g. closed), such as through the placement of a covered stent graft in the vein or artery that covers the flow pathway, or other flow pathway-occlusive procedure. In some embodiments, three or more flow pathways can be created. Multiple flow pathways can be created in similar or dissimilar arteries and/or veins. In some embodiments, single or multiple flow pathways are created that exhibit a cumulative flow rate of at least 400 ml/min and/or no more than 1500 ml/min, such as a flow rate of at least 600 ml/min and/or no more than 1000 ml/min. In some embodiments, a first flow pathway is created between the iliac artery and iliac vein in the patient&#39;s right leg, and a second flow pathway is created between the iliac artery and iliac vein in the patient&#39;s left leg. 
     The method of  FIG. 1  can be performed using real-time imaging, such as real-time imaging provided by a fluoroscope and/or an ultrasound imaging device. 
     The method of  FIG. 1  can be performed to decrease peripheral vascular resistance, such as to decrease infrarenal vascular resistance (e.g. below the kidneys or in a manner to include the great vessels of the aorta and/or the inferior vena cava). Alternatively or additionally, the method can be performed to achieve a physiologic change selected from the group consisting of: increased oxygen delivery by the arterial system; increased blood volume; increased proportion of blood flow to the descending aorta; increased blood flow to the kidneys; increased blood flow outside the kidneys; increased cardiac output; and combinations of these. The method can be constructed and arranged to prevent any significant chronic increase in heart rate. Alternatively or additionally, the method can be constructed and arranged to prevent a decrease in cardiac function. Alternatively or additionally, the method can be constructed and arranged to avoid undesired adverse effects to the kidneys, such as by avoiding the adverse effects that can be encountered in a renal denervation procedure, such as stenosis, lost autonomic control and/or vessel intima damage. 
     In some embodiments, the method is performed to increase oxygenation and/or flow rates associated with the patient&#39;s chemo-receptors, such as to cause a therapeutic change to vascular resistance. In some embodiments, the method is performed to affect or otherwise modify the patient&#39;s central sympathetic tone. Modifications to central sympathetic tone can be performed to reduce systolic and/or diastolic blood pressure (e.g. mean systolic and/or mean diastolic blood pressure), and/or to treat other patient diseases and conditions such as diabetes, sleep apnea, or heart failure. 
     In some embodiments, the method of  FIG. 1  is constructed and arranged to cause a reduction in diastolic blood pressure that is equal to or greater than a concurrent reduction in systolic blood pressure. In some embodiments, the method is constructed and arranged to reduce the diastolic pressure more than the systolic pressure by an amount of at least 2 mmHg, at least 4 mmHg or approximately 5 mmHg. In some embodiments, the method is constructed and arranged to reduce the diastolic pressure by at least 5 mmHg, such as a reduction of at least 10 mmHg, at least 15 mmHg or approximately 18 mmHg. In some embodiments, the method is constructed and arranged to reduce the systolic pressure by at least 5 mmHg, such as a reduction of at least 10 mmHg or approximately 13 mmHg. In some embodiments, the method is constructed and arranged to cause a reduction in blood pressure to a level at or below 130/90 mmHg. 
     Referring now to  FIG. 2 , a system for creating at least one fistula or other flow pathway between a first location in a patient&#39;s arterial system of a patient (e.g. an artery), and a second location in the patient&#39;s venous system (e.g. a vein), is illustrated. System  100  can comprise a vascular introducer, first introducer  110 , configured to be placed into the patient to provide access to a starting vessel. System  100  can comprise another vascular introducer, second introducer  130 , configured to provide access to a target vessel. In some embodiments, the starting vessel is a vein, and the target vessel is an artery. In other embodiments, the starting vessel is an artery and the target vessel is a vein. System  100  can include target wire  120  which can comprise helical section  121  and can be configured to be placed through the second introducer  130  and into the target vessel. Target wire  120  can be placed through an elongate tube, catheter  122 . System  100  can comprise needle deployment device  140  which can be configured to deploy crossing needle  145  (shown in an advanced position in  FIG. 2 ), from the starting vessel and into the target vessel. System  100  can include a vessel-to-vessel guidewire  170 , which can be placed from the starting vessel to the target vessel via needle deployment device  140 . System  100  can also include clip deployment catheter  150 , which can be configured to deploy anastomotic clip  160 . System  100  can include a flow pathway modifying device, such as dilation device  180  including balloon catheter  185  and standard angioplasty balloon indeflator  181 . System  100  can further comprise imaging apparatus  190 , typically a fluoroscope and/or ultrasound imaging device used to image one or more device or components of system  100 , as well as the patient&#39;s anatomy, during the creation of an arteriovenous flow pathway. 
     First introducer  110  can be configured to be placed into the patient to provide access to a starting vessel (e.g. a vein of a patient). In some embodiments, introducer  110  comprises an 11 French vascular introducer. First introducer  110  can comprise beveled tip  111  with an angle ranging from 20° to 50°, such as at an angle of approximately 30°. Additionally, system  100  can include a kit comprising an additional introducer having a second angle providing the clinician or other user (hereinafter “clinician) with more options as may be appropriate for a particular patient&#39;s anatomical geometry. In some embodiments, beveled tip  111  comprises a marker, for example, a radiopaque or other visualizable marker, such that the luminal wall of the starting vessel can be imaged (e.g. when tip  111  is pressed against the vessel wall). The proximal portion of introducer  110  can comprise a contour or marker, such as to be correlated with or otherwise indicate the alignment of the bevel of tip  111 . 
     Introducer  110  can comprise shaft  117  which includes at least one thru lumen. Introducer  110  can also comprise port  116 , typically a hemostasis valve, which can be fluidly connected to the lumen of shaft  117 . A second port  118 , typically a luer connector, can be connected to tubing  115  which in turn can be connected to port  116 . Introducer  110  can further comprise a dilator, not shown but typically an 11 to 13 French dilator used to introduce and/or pre-dilate tissue receiving introducer  110 . Introducer  110  can further comprise a radially expandable element, such as expandable element  119 , such as a balloon or expandable cage located on its distal portion. In some embodiments, expandable element  119  can be configured to prevent advancement of introducer  110  into the target vessel. In yet another embodiment, expandable element  119  can be configured to stabilize the starting vessel during insertion of introducer  110  or another device or component of system  100 . 
     System  100  can comprise second introducer  130  which can be configured to provide access to a target vessel, such as an artery of the patient when the starting vessel is a vein. In some embodiments, second introducer  130  comprises a 4 French vascular introducer. System  100  can comprise target wire  120  configured to be placed through second introducer  130  and into the target vessel. Target wire  120  can comprise helical section  121  configured to be deployed at the site where the flow pathway is to be created. Helical section  121  can be configured to provide structure and support to the site during a procedure. Additionally, target wire  120  can serve as a visual reference during insertion of vessel-to-vessel guidewire  170 , as described herebelow. 
     System  100  can comprise needle deployment device  140 . Needle deployment device  140  can comprise shaft  141  which slidingly receives advanceable crossing needle  145 , shown in an advanced state in  FIG. 2 . Shaft  141  can comprise shaft hub  142  mounted to its proximal end. Shaft  141  can comprise a curved distal portion as shown. Crossing needle  145  can comprise needle hub  146  mounted to its distal end. Movement of needle hub  146  relative to shaft hub  142  can cause crossing needle  145  to advance and retract within shaft  141 . Needle hub  146  can be fully advanced toward shaft hub  142  in the configuration of  FIG. 2 , such that the tip and distal portion of crossing needle  145  is fully advanced out of the distal end of shaft  141 . 
     Crossing needle  145  can comprise a 20 to 24 gauge needle, such as a 22 gauge needle. In some embodiments, the crossing needle comprises a curved distal portion (as shown). The curved distal portions of shaft  141  and/or crossing needle  145  can be aimed at the center of the target vessel prior to insertion into the target vessel. The radius of curvature can be reduced if the clinician has difficulty in aiming the needle tip at the center of the target vessel prior to insertion. Conversely, the radius of curvature can be increased to sufficiently aim the needle tip at the center of the target vessel. Additionally, the crossing needle  145  can comprise a marker, not shown but indicating the direction of curvature. Examples of markers include, but are not limited to: a flat surface; a textured surface; a visualizable marker such as a radiopaque marker; a magnetic marker; an ultrasonic marker or a visible marker; and combinations of these. In some embodiments, crossing needle comprises a shaped memory alloy, for example, nickel titanium alloy. In some embodiments, shaft hub  142  and/or needle hub  146  comprise a marker or other visible demarcation (e.g. a flat portion) which correlates to the direction of curvature of shaft  141  and/or crossing needle  145 , respectively. 
     System  100  can comprise a guidewire to be placed from the starting vessel to the target vessel, vessel-to-vessel guidewire  170 . Guidewire  170  can be configured to be placed via needle deployment device  140 . In some embodiments, vessel-to-vessel guidewire  170  comprises a wire with an outer diameter of approximately 0.018″. Vessel-to-vessel guidewire  170  can comprise a marker, not shown but configured to indicate the flow pathway location. In some embodiments, vessel-to-vessel guidewire  170  comprises a distal portion and a mid portion. Guidewire  170  mid portion can comprise a different construction than the distal portion. For example, the mid portion of guidewire  170  can be stiffer than the distal portion. 
     System  100  can comprise clip deployment catheter  150  configured to house and deploy anastomotic clip  160 . Clip  160  can comprise a plurality of distal arms  161  and a plurality of proximal arms  162 , which can be deployed simultaneously or independently. Clip  160  can comprise at least two distal arms  161  and at least two proximal arms  162  configured to deploy and engage the starting vessel and the target vessel. In some embodiments, clip  160  comprises four deployable distal arms  161  and four deployable proximal arms  162 . Clip  160  can comprise a shaped memory alloy, such as nickel titanium alloy. In some embodiments, clip  160  is constructed and arranged as described in applicant&#39;s U.S. Pat. No. 7,828,814, entitled “Device and Method for Establishing an Artificial Arterio-Venous Fistula”, filed Apr. 4, 2007, the contents of which are incorporated herein by reference in its entirety. 
     In some embodiments, clip  160  is biodegradable or includes one or more biodegradable portions (e.g. one or more portions of clip are absorbed or otherwise degrade over time). In some embodiments, clip  160  comprises a biodegradable anastomotic device such as is described in applicant&#39;s co-pending U.S. Non-Provisional Application Ser. No. 12/752,397, entitled “Device and Method for Establishing an Artificial Arteriovenous Fistula”, filed Apr. 1, 2010, the contents of which are incorporated herein by reference in its entirety. 
     Clip deployment catheter  150  can comprise shaft  151 . Mounted to the proximal end of shaft  151  can be handle  153 . On the proximal end of handle  153  can be port  155 , which can be operably attached to shaft  151  such that a guidewire can travel from the distal end of shaft  151  to port  155 , such as guidewire  170  after it has been previously placed between a starting vessel and a target vessel as has been described hereabove. Shaft  151  can comprise one or more tubular portions, such as an inner tubular segment that houses clip  160 , and an outer tubular segment that covers clip  160  but can be retracted to deploy clip  160 , such as is described in applicant&#39;s U.S. Pat. No. 8,641,747, entitled “Devices for Arterio-Venous Fistula Creation”, filed Jun. 13, 2005, the contents of which is incorporated herein by reference in its entirety. 
     Handle  153  can further include control  152  (e.g. a button, slide or lever), where control  152  can be operably configured to allow an operator to deploy distal arms  161  and/or proximal arms  162  of clip  160 , such as via retraction of an outer tube or sheath portion of shaft  151  that can be covering one or more portions of clip  160 . In some embodiments, a click or other tactile feedback is provided during retraction of a sheath portion of shaft  151 . Control  152  can be moved via a stepped or otherwise segmented slot  156 . Distal arms  161  can be deployed via moving control  152  from a “first ready to deploy” position to a “first deployed” position which can be achieved by moving control  152  relatively parallel to the longitudinal axis of handle  153 . The at least two proximal arms  162  can be queued to be deployed via moving control  152  from the first deployed position to a “second ready to deploy” position. The second ready to deploy position can be achieved by moving control  152  in a direction perpendicular to the longitudinal axis of the handle. Subsequently, proximal arms  162  can be deployed via moving control  152  from the second ready to be deployed position to a “second deployed” position via a motion parallel to the longitudinal axis of the handle. In this embodiment, control  152  can include a safety position comprising a ready to deploy position which can be transitioned by moving control  152  in a direction that is perpendicular to the axis of handle  153 . This control advancement arrangement can prevent inadvertent deployment of distal arms  161  and/or proximal arms  162 . 
     In some embodiments, prior to deployment of one or more arms of clip  160 , introducer  110  is advanced such that beveled tip  111  applies a force to the wall of the starting vessel. Sufficient force can be applied by introducer  110  to enable an operator to “seat” the starting vessel against the target vessel to assist in properly deployment of clip  160 . 
     In some embodiments, clip deployment catheter  150  can be configured to recapture distal arms  161  and/or proximal arms  162 . For example, clip deployment catheter  150  can deploy at least one distal arm  161  and subsequently recapture the at least one distal arm  161 . 
     Clip deployment catheter  150  and/or clip  160  can further comprise at least one marker, not shown but typically a radiopaque and/or ultrasonic marker configured to assist in the rotational positioning of clip  160  at the flow pathway location. For example, the marker can be oriented toward the target vessel prior to deployment of clip  160 . In some embodiments, a marker is included on the distal portion of clip deployment catheter  150 . In some embodiments, handle  153  comprises one or more markers that are circumferentially aligned with clip  160  prior to its deployment. In some embodiments, clip deployment catheter  150  and/or clip  160  comprise at least one marker configured to longitudinally position clip  160  at the flow pathway location. In these embodiments, the marker can indicate the distal and/or proximal end of clip  160 . 
     Clip deployment catheter  150  can further comprise a projection and/or recess, neither shown but configured to mechanically engage clip  160 . The project and/or pin can be used to stabilize clip  160  with shaft  151 , such as when an outer tubular portion of shaft  151  is advanced or retracted. 
     System  100  can comprise dilation device  180  configured to dilate clip  160  and/or the flow pathway. Dilation device  180  can include balloon catheter  185 , such as a standard angioplasty balloon catheter comprising balloon  186 . Attached to the proximal end of catheter  185  can be indeflator  181 , typically a standard balloon indeflator device. Alternatively, balloon  186  can comprise a non-balloon expandable such as an expandable cage or radially deployable arms configured to dilate the flow pathway. Catheter  185  can be configured to track over a vessel-to-vessel guidewire, such as guidewire  170  placed between a vein and an artery, such that balloon  186  can be positioned within the flow pathway (e.g. within clip  160 ). Typically, dilation device  180  can expand to a diameter of less than five millimeters, and more typically to a diameter of approximately four millimeters. In some embodiments, a second dilation device  180  is included, such as a device configured to expand to a different diameter than the first dilation device. 
     System  100  can include patient imaging apparatus  190 . Non-limiting examples of an imaging apparatus include: x-ray; fluoroscope; ultrasound imager; MRI; and combinations of these. The imaging apparatus can allow the clinician to track the movement of all components comprising system  100  as well as view the position of the starting and target vessel relative to each other, as described in detail herein. 
     In an exemplary procedure illustrated in  FIGS. 3A-D , an anastomotic clip can be deployed to create an iliac arteriovenous flow pathway (e.g. an arteriovenous fistula). Vascular venous and arterial access can be obtained using standard interventional techniques (e.g. through a femoral vein and femoral artery).  FIGS. 3A and 3B  illustrate an anastomotic clip delivery device that can be used, including an anastomotic clip that can be implanted. In some embodiments, the anastomotic clip delivery device comprises clip deployment catheter  150 , and the anastomotic clip comprises clip  160 , each of  FIG. 2  hereabove. In  FIG. 3C , an angiogram of the flow pathway location AVF is illustrated, including artery A and vein V, prior to flow pathway creation. A radiopaque vessel targeting wire CW, such as wire  120  of  FIG. 2 , can be inserted within artery A to provide a radiographic outline of the artery. A venogram can be performed to outline the vein and confirm proximity of the artery and vein at the target crossing location AVF for the creation of the arteriovenous flow pathway. A crossing needle device (e.g. a 22 gauge or 23 gauge crossing needle device), such as needle deployment device  140  of  FIG. 2  hereabove, can be placed into vein V, such as a placement over a guidewire and through an introducer device (e.g. introducer  110  of  FIG. 2 ). The crossing needle of the device can be advanced through the wall of vein V into artery A, and a guidewire can be advanced through a lumen of the crossing needle and into artery A. The crossing needle can be subsequently removed and the anastomotic clip delivery system can be tracked across the puncture site. The anastomotic clip can then be deployed so that the expanded arms of the anastomotic clip attach to the inner walls of artery A and vein V, and the retention arms maintain the anastomotic clip in the proper position (deployed position shown in  FIG. 3D ). After removal of the delivery system, a balloon catheter (e.g. a 2.5-4.5 mm balloon catheter) can be inserted into the center of the anastomotic clip and inflated to expand the anastomotic clip to a target diameter as described herein. The balloon can then be deflated and removed. An angiogram can confirm the patency of the flow pathway. 
     Referring now to  FIG. 4 , a flow chart of a method of creating a flow pathway between a starting vessel and a target vessel at a flow pathway location, consistent with the present inventive concepts is illustrated. In Step  410 , a procedural planning assessment of a patient is performed. Step  420  comprises placing a first introducer into a starting vessel, e.g. a vein, and placing a second introducer into a target vessel, e.g. an artery. In Step  430 , an angiographic orientation is performed and a flow pathway location is selected. Step  440  comprises placing a vessel-to-vessel guidewire between the vein and the artery. Step  450  comprises placing an anastomotic clip at the flow pathway location. In some embodiments, system  100  and/or one or more components of system  100  of  FIG. 2  are used to perform the method of  FIG. 4 . 
     The starting vessel can comprise a vein, and can be selected from the group consisting of: inferior vena cava (IVC); saphenous; femoral; iliac; popliteal; brachial; basilic; cephalic; medial forearm; medial cubital; axillary; and jugular. The target vessel can comprise an artery, and can be selected from the group consisting of: aorta; axillary; brachial; ulnar; radial; profundal; femoral; iliac; popliteal and carotid. In a preferred embodiment, the starting vessel and target vessel can comprise an external iliac. In an alternate embodiment, the starting vessel can comprise an artery and the target vessel can comprise a vein. 
     Step  410 , the first step in the illustrated method of the present inventive concepts comprises procedural planning. This step comprises properly orienting the vein and the artery, meaning a clinician becomes familiar with the anatomical orientation of the vein and artery relative to each other. Understanding the orientation of the vessels with respect to one another can be achieved through analysis of one or more images provided by an imaging apparatus (e.g. a fluoroscope) such as imaging apparatus  190  of  FIG. 2 . In some embodiments, at least one of the vein or artery has a diameter of at least five millimeters proximate the flow pathway location. In another embodiment, both the vein and artery have a diameter of at least five millimeters proximate the flow pathway location. 
     In Step  420 , the method comprises placing a first introducer into the vein. Preferably, the first introducer comprises an 11 French introducer having a beveled tip, such as introducer  110  of  FIG. 2  described hereabove. In some instances, the beveled tip of the first introducer can be rotated during insertion into the vein. Rotation of the introducer can be helpful during insertion into the starting vessel due to the tendency of the beveled tip to lift and pull back. Additionally or alternatively, the introducer can be vibrated while it is advanced into the vein. Step  420  can further comprise pre-dilating the vein with a dilator, preferably a 13 French dilator, prior to placing the introducer into the vein. Additionally, a second introducer can be placed into the artery. Preferably, the second introducer comprises a 4 French introducer, such as second introducer  130  described in  FIG. 2  hereabove. The method further comprises placing a target wire into the second introducer and then into the artery such that the distal end of the target wire is positioned five to ten centimeters past the flow pathway location, and configured to serve as a visual reference to a clinician. The target wire, typically including a helical section, is advanced. The advancement can be combined with retracting the introducer such that the helical section of the wire is deployed at the targeted anastomotic site. 
     In Step  430 , the method comprises performing angiographic orientation and selecting a flow pathway location. Choosing the flow pathway location can be based upon a lack of thrombus or other soft tissue occlusive matter at the vascular location, as well as lack of plaque or calcified matter. Preferably, the flow pathway location is chosen at a location where the vein is less than or equal to three millimeters apart from the artery. Techniques can be used to image the vein and artery in side-by-side configurations as well as overlapping (i.e. on top of each other in the image) orientations. Rotation of the imaging device 90° can modify the provided image from a side-by-side image to an overlapping image, and back again. In some embodiments, after a flow pathway location has been selected, a clinician can orient the fluoroscope such that the vein and artery are shown overlapping, such as with the vein on top of the artery. In some embodiments, the clinician can position a fluoroscope or other imaging device at an angle to the patient approximating 35° RAO. 
     In Step  440 , the method comprises placing a vessel-to-vessel guidewire into the vein, such as while the vein and artery are imaged in an overlapping orientation, as described in Step  430  hereabove. A next step comprises placing a needle delivery device over the vessel-to-vessel guidewire and into the vein. The needle delivery device can comprise a marker, as described in  FIG. 2  hereabove, such that a clinician can orient the marker toward the artery. The guidewire can be retracted and subsequently, the needle of the needle delivery device can be advanced toward the target wire and toward the artery. In some embodiments, the vessel-to-vessel guidewire can be placed through a dilator. 
     Prior to inserting the crossing needle into the artery, a clinician can aim the needle tip at the center of the artery to ensure desired engagement of the artery with the needle, such as by rotating the proximal end of the needle or a device containing the needle. In some embodiments, the needle or needle delivery device includes a proximal hub with a demarcation (e.g. a flat portion or a marker) positioned to indicate the orientation of a curved distal portion of the needle, such as is described in reference to needle deployment device  140  of  FIG. 2  hereabove. In this operation, a clinician can torque or otherwise rotate the needle such that the direction of the needle curvature comes into view on the imaging apparatus (e.g. fluoroscope). Confirming the direction of needle curvature ensures that the needle is to be advanced in the desired direction, such as into the center of the artery. In some embodiments, a target wire is placed in the target vessel, such as target wire  120  of  FIG. 2  described hereabove. Preferably, the needle comprises a curved tip, and the radius of curvature can be reduced if a clinician has difficulty in aiming the needle at the center of the target vessel prior to insertion. Conversely, the radius of curvature can be increased to sufficiently aim the needle tip at the center of the target vessel. In some embodiments, the needle delivery catheter is oriented as described in reference to  FIG. 5  herebelow. 
     Additionally, a clinician can confirm that the distal portion of the vessel-to-vessel guidewire is located within the lumen of the artery. Also, the clinician can confirm the vessel-to-vessel guidewire is parallel with the target wire previously placed in the artery. A clinician can confirm that the needle is positioned within the target vessel by using a dye injection through the needle. Alternatively or additionally, a clinician can confirm that the needle is properly positioned in a target vessel by measuring the pressure in a distal portion of the needle, such as to confirm presence in an artery by confirming arterial pressure is recorded. 
     In some embodiments, the needle deployment device is placed into the artery and the guidewire is advanced from the artery into the vein via the crossing needle. In these embodiments, the anastomotic clip delivery catheter can also be advanced from artery to vein. 
     In Step  450 , the method comprises placing an anastomotic clip at a flow pathway location. Prior to performing Step  450 , placing an anastomotic clip at a flow pathway location, a user can retract the crossing needle while maintaining the position of the target wire. Next, the target wire can be removed from the second introducer. The target wire can also be removed after Step  450 . 
     In Step  450 , a user can position the vein and artery such that the vein and artery are slightly apart from each other on the image (e.g. not overlapping). In one embodiment, this can be achieved by rotating a fluoroscopy unit 45° to 90° after an overlapping image is obtained (e.g. an image obtained during a dual contrast injection of both the artery and vein). 
     Next, the tip of the clip deployment catheter (with a pre-loaded anastomotic clip) can be placed at the flow pathway site. In this step, a clinician can apply forward pressure and rotate the clip deployment catheter. The clip can comprise at least two distal arms and at least two proximal arms that can be deployed simultaneously or independently via a control located on the handle of the catheter. 
     Step  450  further comprises deploying the anastomotic clip in the flow pathway, such as is described in detail in reference to clip deployment catheter  150  of  FIG. 2  hereabove. The clip distal arms are deployed by moving a control on the clip deployment catheter from a ready to deploy position to a first deployed position, which can be achieved by moving the control relatively parallel to the longitudinal axis of the handle. Prior to deploying the proximal arms of the clip, a clinician can retract the first introducer to the flow pathway location and seat the vein against the artery. The clip deployment catheter can comprise a marker located on its distal end. Using this marker, a clinician can pull the clip deployment catheter back such that the marker is aligned with the distal end of the first introducer. 
     In a next operation of STEP  450 , the proximal arms can be queued to be deployed via moving the control from a first deployed position to a second ready to deploy position. The ready to deploy position can be achieved by moving the control in a direction perpendicular to the longitudinal axis of the handle. Subsequently, the proximal arms can be deployed via moving the control from the second ready to be deployed position to the second deployed position via a motion parallel to the longitudinal axis of the handle. In this embodiment, the control includes a safety position comprising a ready to deploy position which can be transitioned by moving the control in a direction that is perpendicular to the axis of the handle. This control arrangement can prevent inadvertent deployment of the distal and/or proximal arms. After deployment of the proximal arms, a clinician can retract the first introducer from the anastomosis site, such as a retraction of approximately two to three centimeters, followed by retracting the clip deployment catheter. 
     The method can further comprise dilating the flow pathway via a balloon or other expandable member. For example, a clinician can track a balloon catheter over the target wire and inflate the balloon. In a typical embodiment, the balloon catheter comprises a diameter of four to five millimeters and can be inflated via a four millimeter by one and one half centimeter non-conforming balloon and indeflator device. The balloon then can be deflated and retracted out of the implant. 
     The method can further comprise verifying clip patency. This can be achieved via a contrast/saline solution injected into the second introducer. A clinician can then remove all devices once it is confirmed that the clip is positioned as desired. 
     The method can further comprise placing a second anastomotic clip, such as a second anastomotic clip  160  of  FIG. 2  described hereabove. Alternatively or additionally, the method can further comprise creating a second flow pathway between, such as a second flow pathway created during the same clinical procedure or a subsequent clinical procedure. The second flow pathway can be between the same two vascular locations as the first flow pathway, or one or both of the second flow pathway vascular locations can be different (e.g. a different vein and/or artery). 
     Referring now to  FIG. 5 , an angiographic view of a patient&#39;s vein and artery prior to advancement of a needle into the artery is illustrated, such as can be performed in Step  440  of the method of  FIG. 4  described hereabove, consistent with the present inventive concepts. In the illustrated embodiment, a clinician has oriented an imaging device (e.g. a fluoroscope or other imaging device of  FIG. 1 ), such that the segments of vein and artery at a proposed flow pathway location are overlapping (i.e. on top of each other in the image). The clinician has placed a target wire  120  into a patient&#39;s artery such that the helical section  121  can be positioned at the proposed flow pathway location. Additionally, needle deployment device  140  has been advanced intraluminally through the vein as shown such that its distal end is proximal to the proposed flow pathway location. A next step can comprise advancing needle  145  toward the helical section  121  at the proposed flow pathway location. 
     Prior to insertion of needle  145  into the artery, a clinician can rotate needle deployment device  140  such that the direction of the needle deployment device  140  curvature can be viewed (i.e. a non-linear, curved segment can be visualized) on the imaging apparatus. Confirming the direction of curvature ensures that needle  145  can be advanced in the desired direction, such as into the center of the artery. For example, if a clinician rotates needle deployment device  140  such that its tip is positioned as shown in  FIG. 5A or 5C , a clinician will be aiming to an off-center location of the patient&#39;s artery. If a clinician rotates needle deployment device  140  such that its tip is positioned as shown if  FIG. 5B , needle  145  will subsequently be advanced into the relative center of the patient&#39;s artery. The radius of curvature of a needle deployment device  140  can be reduced (e.g. by manual reshaping or by selected a different needle deployment device  140 ) if a clinician has difficulty in aiming needle  145  at the center of the artery prior to insertion. Conversely, the radius of curvature of needle deployment device  140  can be increased to create a more desirable needle  145  advancement trajectory. 
     Referring now to  FIG. 6 , a perspective view of an anastomotic clip is illustrated, consistent with the present inventive concepts. Clip  160  can comprise at least two distal arms  161  and at least two proximal arms  162 . In the illustrated embodiment, clip  160  comprises four distal arms  161  and four proximal arms  162 . In some embodiments, clip  160  is constructed and arranged as described in applicant&#39;s U.S. Pat. No. 7,828,814, entitled “Device and Method for Establishing an Artificial Arterio-Venous Fistula”, filed Apr. 4, 2007, the contents of which are incorporated herein by reference in its entirety 
     Clip  160  can be formed from a single tube of resilient material, such as nickel titanium alloy, spring steel, glass or carbon composites or polymers, or pseudoelastic (at body temperature) material such as nickel titanium alloy or comparable alloys and polymers, by laser cutting several closed-ended slots along the length of the tube (leaving the extreme distal and proximal edges of the tube intact) and cutting open-ended slots from the longitudinal center of the tube through the distal and proximal edges of the tube. The open-ended slots are cut between each pair of closed-end slots to form a number of loops joined at the center section by waist segments. Many other fabrication techniques can be utilized, for example, clip  160  can be made of several loops of wire welded together at the waist section. 
     After the tube is cut as described above, it can be formed into its eventual resiliently expanded configuration. In this configuration, the loops turn radially outwardly from the center section, and evert toward the center plane of the center section, thus forming clinch members, i.e. distal arms  161  and proximal arms  162 , in the form of arcuate, everted, petaloid frames at either end of the loop, extending from the generally tubular center section formed by waist segments. For clarity, the term everted is used here to mean that the arc over which the petaloid frame runs is such that the inside surface of clip  160  faces radially outwardly from the cylinder established by the tube. 
     Once clip  160  has resiliently expanded to the extent possible given its impingement upon the walls of the starting vessel and the target vessel, the center section can be further expanded by plastic deformation. This can be accomplished by inflating a balloon, not shown, within the center section and expanding the center section beyond its elastic or superelastic deformation range. By plastically deforming the center section of clip  160 , the center section becomes more rigid and able to withstand the compressive force of the walls of the starting and target vessels. 
     As illustrated, the construction provides several pairs of longitudinally opposed (that is, they bend to come into close proximity to each other, and perhaps but not necessarily, touch) and aligned (they are disposed along the same longitudinal line) distal arms  161  and proximal arms  162 . Overall, the petaloid frames of distal arms  161  form a “corolla,” analogous to the corolla of a flower, flange or rivet clinch, which impinges on the starting vessel wall and prevents expulsion into the target vessel, and the petaloid frames of proximal arms  162  form a corolla, flange or rivet clinch (this clinch would be analogous to a rivet head, but it is formed like the clinch after insertion of the rivet), which impinges on the target vessel wall and prevents the expulsion of clip  160  into the target vessel. Also, the central section forms a short length of rigid tubing to keep the flow pathway open. The resilient apposition of the at least two distal arms  161  and at least two proximal arms  162  will securely hold clip  160  in place by resiliently clamping the walls of the starting vessel and the target vessel, even over a considerable range of wall thickness or “grip range.” 
     The respective lengths of arms  161  and  162  can be variably sized to maximize or optimize the stability of clip  160  with respect to the vessels when deployed between adjacent vessels. Moreover, varying the lengths of the respective arms can further provide additional advantages. For instance, the arms which are shortened in length can facilitate the positioning and securement of clip  160  between the vessels by allowing for the relatively shorter member to swing into position within the vessel lumen during deployment, as described in further detail below. Additionally, a shorter member can provide for a minimized implant size when placed against the vessel interior wall for securement as well as a mitigating any physiologic reaction to the implant, e.g., a reduction in thrombosis, etc. Additionally, arms  161  and/or  162  which are lengthened relative to other arms can provide for increased clip stability by increasing the amount of force applied against the tissue walls. 
     Moreover, arms having different lengths can additionally place the adjacent vessels in tension such that the vessel walls are drawn towards one another and arms  161  and/or  162  contact the vessel luminal walls to stabilize not only clip  160  within the vessels but also the vessels with respect to one another. Additionally, having one or more arms, such as distal arms  161 , sized to have a length shorter than its respective apposed clinch member can also facilitate the deployment and/or positioning of distal arms  161  within the vessel since the shorter length clinch members can more easily “swing” through an arc within the vessel lumen without contacting the interior walls. Arms with differing lengths can further be configured to align along different planes when deployed to facilitate vessel separation, if so desired. 
     Clip  160  can further comprise at least one marker, not shown, configured to rotationally position the clip at the flow pathway location. For example, a marker can be oriented toward the target vessel prior to deployment of clip  160 . Alternatively or additionally, a marker can be oriented based upon a patient image, e.g. a real-time fluoroscopy image. In yet another embodiment, clip  160  can comprise at least one marker configured to longitudinally position the clip at the flow pathway location. A marker can indicate the distal and/or proximal end of clip  160 . 
     Clip  160  can further comprise holes  164  configured to engage a clip delivery catheter projection such as to allow the shaft of the clip deployment catheter, not shown, to be retracted while clip  160  remains positioned in the distal portion of the shaft. In one embodiment, holes  164  are constructed and arranged about the clip asymmetrically such that clip  160  can be attached in the proper orientation. 
     While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Modification or combinations of the above-described assemblies, other embodiments, configurations, and methods for carrying out the invention, and variations of aspects of the invention that are obvious to those of skill in the art are intended to be within the scope of the claims. In addition, where this application has listed the steps of a method or procedure in a specific order, it may be possible, or even expedient in certain circumstances, to change the order in which some steps are performed, and it is intended that the particular steps of the method or procedure claim set forth herebelow not be construed as being order-specific unless such order specificity is expressly stated in the claim.