Anti-clotting indwelling catheter

Description of equivalent WO 2005025645 A2

ANTI-CLOTTING INDWELLING CATHETER

0002Cross-Reference to Related Application This application claims the benefit of the filing date of Provisional Application Ser. No. 60/501,155, filed on Sept. 8, 2003, which is incorporated herein by reference in its entirety.

0003BACKGROUND Patients with end stage renal disease (ESRD) must routinely receive dialysis treatments in order to live. Indwelling catheters are a useful dialysis access method for hemodialysis because they reduce the number of vein penetrations needed for repeated dialysis. Chronic central venous catheters for dialysis (CVCD) are the major long-term dialysis access for over 25% of ERSD patients or hemodialysis. In a standard flow-through dialysis system, the CVCD must provide a first route for removal of blood and a second route for return of blood at a rate of at least 300 ml/min. A CVCD for a standard flow-through dialysis system can be formed by inserting two separate catheters into the jugular vein in a manner that forms a tunnel over the clavicle. In this arrangement, the catheter tips rest near the junction of the superior vena cava with the right atrium. The tip of the blood removal catheter, or arterial catheter, is placed 3-4 cm above the tip of the downstream blood return catheter, or venous catheter, in order to prevent mixture of cleansed blood with blood entering the arterial catheter. As an alternative to the separate catheter for the standard flow -through dialysis system, a single-bodied catheter with two separate lumens can be used for dialysis access. In this arrangement, the tip of the arterial lumen is placed 3-4 cm above the tip of the venous lumen. Like the standard flow-through arrangement, this arrangement also prevents mixture of cleansed blood with blood entering the arterial lumen. As yet another alternative, dialysis can also be performed by using a single catheter with a single lumen. In this case, the dialysis machine delivers a quantity of untreated blood and then returns treated blood in alternating cycles. Blood enters and exits the catheter lumen through ports or holes in the catheter. The design of these ports is highly variable, and similar concepts are employed in both single and dual lumen catheters. A first example is a catheter lumen having a single port at the tip for entrance or exit of blood. A second example is a catheter lumen having a blood exchange port located on the side of the lumen body toward its distal tip. Another example is a catheter lumen having multiple blood exchange ports axially placed around the side of the lumen body toward its distal tip. While all of the above CVCD designs work, there is room for improvement in the field, and there are problems with all current port designs for dialysis catheters. Arterial catheter lumens that contain only one blood exchange port, no matter its location, run the risk of obstruction of the port by neighboring vein walls, by blood clotting in the exchange port, and by growth of a fibrin sheath around the distal end of the lumen and exchange port. Venous catheter lumens that contain only one blood exchange port, no matter its location, run the risk of obstruction by blood clotting in the exchange port and by growth of a fibrin sheath around the distal end of the lumen and the exchange port. Obstruction of the blood exchange port prevents the desired blood exchange rate of at least 300 ml/min from occurring. The degree of obstruction may render the indwelling catheter(s) ineffective for dialysis access. Therefore, when this level of obstruction occurs, the indwelling catheter(s) must be replaced. Arterial catheter lumens containing multiple blood exchange ports around the distal end of the catheter reduce the occurrence of vein obstruction. However, the presence of multiple ports increases the risk of obstruction by blood clots because the multiple ports allow blood to flow into the lumen when idle, which can wash out the anticoagulant solution. The diminished presence of anticoagulant solution at the distal end of the catheter increases the amount of blood clotting in the ports and lumen. Obstruction of the blood exchange ports prevents the desired blood exchange rate of at least 300 ml/min from occurring. The degree of obstruction may render the indwelling catheter(s) ineffective for dialysis access. Therefore, when this level of obstruction occurs, the indwelling catheter(s) must be replaced. Thus, there is a general need in the industry to provide methods and devices for the prevention of obstructions in the blood exchange ports of catheters and around the distal end of catheters. It is desired that these methods and devices prevent obstructions of the lumen due to clotting and fibrous sheath encasement of the tip of the catheter, as well as maintain the catheter anti-coagulant lock solution inside the lumen during idle periods between dialysis. SUMMARY The present invention is directed to an indwelling catheter. More particularly, but not exclusively, one aspect relates to an indwelling catheter adapted to prevent clotting and sheathing of the catheter's distal end. One application of the catheter includes non-exclusive use as a catheter for dialysis (CVCD). Other applications are also contemplated. Another aspect relates to a catheter with a lumen for blood flow that includes a deformable wall portion to provide a path for blood flow in a first configuration and substantially closes the path when in a second configuration. Expansion of the walls of the catheter will also break loose any fibrous sheath beginning to form around the catheter tip A further aspect relates to a catheter with a lumen for blood flow that includes a wall portion that is deformed to open and close one or more ports in the wall portion by axially displacing a distal portion of the catheter including the one or more ports relative to a proximal portion of the catheter. A further aspect relates to a catheter with a lumen for blood flow that includes a wall portion that is deformed to open and close one or more ports in the wall portion by radially deforming a distal portion of the catheter including the one or more ports. A further aspect relates to a catheter with a lumen for blood flow that includes a wall portion that is deformed to open one or more ports in the wall portion by simultaneously axially and radially displacing a distal end of the catheter relative to a proximal portion of the catheter. Yet another aspect relates to a catheter with a lumen for blood flow that includes a wall portion having a first shape to provide a port for blood flow and a second shape that substantially closes the port to prevent flow through the port. Another aspect relates to a catheter with a lumen for blood flow that includes one or more ports that are opened by reducing a length of at least a portion of the catheter that includes the one or more ports. A further aspect relates to a catheter that includes a self-closing port that retains a catheter lock solution in a lumen of the catheter when closed and permits blood flow through the passage when opened. Various means for opening and closing the catheter port are contemplated, including mechanical, pneumatic and hydraulic means. The closing means can be remotely actuated so that the port can remain indwelled in the patient while the port is opened and closed. These and other aspects are further discussed below.

0004BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a distal portion of a catheter with open ports according to one embodiment of the invention. Fig. 2 is an elevation of the catheter of Fig. 1 with the ports in a closed condition. Fig. 3 is an elevation of the catheter of Fig. 1 with the ports in an opened condition Fig. 4 is a sectional view through the body of the catheter of Fig. 1 taken transversely to its longitudinal axis. Fig. 5 is a longitudinal sectional view of one embodiment actuating mechanism for opening and closing the catheter of Fig. 1. Fig. 6 is a longitudinal sectional view of another embodiment actuating mechanism. Fig. 7 is a sectional view through line 7-7 of Fig. 6. Fig. 8 is a longitudinal elevation view in partial section view of another embodiment actuating mechanism. Fig. 9 is an elevation view of a hub member comprising a portion of the actuating mechanism of Fig. 8. Fig. 10 is a perspective view of another embodiment actuating mechanism and its position when the ports are in a closed condition. Fig. 11 is a perspective view of the actuating mechanism of Fig. 10 and its position with the ports in an open condition. Fig. 12 is an elevation view of a distal portion of another embodiment catheter with its ports in a closed condition. Fig. 13 is an elevation view of the catheter of Fig. 12 with its ports in an opened condition. Fig. 14 is a sectional view through line 14-14 of Fig. 13. Fig. 15 is a perspective view of a distal portion of another embodiment catheter with its ports in a closed condition. Fig. 16 is the distal portion of the catheter of Fig. 15 with its ports in an open position. DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS For the purposes of promoting an understanding of the principles of the inventions, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the inventions is thereby intended. Any alterations and further modifications of the principles of the inventions as illustrated or described herein are contemplated as would normally occur to one skilled in the art to which the inventions relate. The present invention provides a catheter with at least one port adjacent a distal end of the catheter that can be selectively opened and closed. The at least one port can be open or closed while the at least one port is located in a vascular structure of a patient, such as a vein or artery. One application of the catheter contemplates that it is used in dialysis procedures, although other indwelling applications are also contemplated. The at least one port will be in the closed position between dialysis procedures to prevent blood from flowing through the port and to prevent clotting within the tip of the catheter. With the at least one port closed, the catheter can be injected with anticoagulant solution and the solution is retained within the catheter lumen. It is contemplated that the at least one port allows fluid egress easier than fluid ingress when closed. Thus the concentration of anticoagulant within the lumen of the catheter can be maintained at the same level for many days or even weeks when the at least one port is closed. During dialysis, at least one port is opened by deforming the wall adjacent to the at least one port to allow ingress of blood through the port and into the lumen of the catheter. It is contemplated that opening the at least one port can lift the distal end of the catheter from the neighboring vessel surface, avoiding occlusion of the at least one port by a wall surface of the vessel structure. Further, opening of the at least one port can break loose any fibrous sheath that is forming around the distal end of the catheter adjacent the at least one port. Repeated opening and closing of the at least one port can provide a measure to prevent formation of a fibrous sheath around the distal end of the catheter. The catheter can be made from any suitable bio-compatible material, including silicone, polyurethane, polyurethane-polycarbonate copolymer, or any other plastic or polymer material. The catheter can also include an antibacterial coating. The catheter can also be treated with an anti-infection agent, such as methylene blue, for example. The catheter can be of any suitable size for placement in a vessel structure, including sizes ranging from 8 to 15 French. Other sizes are also contemplated. The outer wall surface of the catheter can be cylindrical, D-shaped, double D-shaped, or split, for example. The catheter can also include a single lumen or multiple lumens. Referring to Figs. 1-3, there is shown a distal portion of a catheter 10 including a body 12 and a distal end 14. One or more ports 16 are provided adjacent distal end 14, and extend through wall 18 of body 12 in communication with a lumen 20. Distal end 14 can be closed with an integral tip or cap to prevent fluid flow therethrough. In the illustrated embodiment, each port 16 is an elongated slit or gill that extends generally parallel to the longitudinal axis 13 of body 12. Other embodiments contemplate other configurations for ports 16, including slits that extend transversely to the longitudinal axis 13 of body 12 and rounded openings with valve members that are opened and closed. In Figs. 1-3, three ports 16 are provided in wall 18 that extend along the longitudinal axis of body 12 and are spaced radially about body 12 approximately 120 degrees apart from one another. Other embodiments contemplate one more ports 16, including two ports, four ports, or five or more ports. It is further contemplated that the ports can be evenly spaced or unevenly spaced about body 12. In the illustrated embodiment each port 16 includes a distal end spaced a distance LI from distal end 14, and extends along axis 13 for a length L2 to a proximal end of port 16. In one specific embodiment, length LI is 5 millimeters and length L2 is 15 millimeters. It should be understood, however, that other distances for LI and L2 are also contemplated, ranging from more than 0 millimeters to 20 or more millimeters. Body 12 is comprised of a material with sufficient flexibility at least adjacent distal end 12 to facilitate manipulation of wall 18 to open and close ports 16. In Fig. 2, body 12 is in a first configuration or condition where ports 16 are closed. It is contemplated that in the closed condition wall 18 substantially seals ports 16 to prevent fluid flow from exiting or entering lumen 20 through ports 16 under a low pressure gradient. During injection of the catheter, enough pressure is generated to cause the lock solution to exit from the closed ports. In Figs. 1 and 3, wall 18 has been manipulated to open one or more of the ports 16 to provide fluid communication between lumen 20 and an exterior of body 12. Manipulation of wall 18 can include displacing or deforming adjacent portions of wall 18 along port 16. The deformed wall portions can provide a rounded or bulbous shape along ports 16. In one embodiment, ports 16 are opened by deforming wall 18 along ports 16 to reduce length L2 to length L3. One or more portions of wall 18 along ports 16 can be radially expanded or separated from an adjacent wall portion to open ports 16. The deformed portions of wall 18 can break loose any fibrous sheath formed thereabout. Furthermore, deformation of wall 18 can provide ports 16 with sufficient size to accommodate any required blood flow through lumen 20. When ports 16 are closed, portions of wall 18 along ports 16 abut one another along the entire length of each port 16 and with sufficient force to prevent fluid ingress and egress through wall 18 between lumen 20 and the vessel structure, and allow egress of fluid only under moderately positive pressure such as when filling the catheter with a lock solution. It is further contemplated that an actuating assembly can be provided to facilitate opening and closing of ports 16, and maintain ports 16 in their opened and closed conditions. The actuating assembly can include an actuator adjacent a proximal end portion of catheter 10 so that the actuator is positioned outside the body of the patient and readily accessible by the surgeon. The actuating assembly can further include one or more actuating members coupled to the actuator and extending along the catheter to a location adjacent ports 16. The actuating members are movable or operable with the actuator to manipulate wall 18 and open or close ports 16 as desired. In Fig. 4 there is shown a cross-section of body 12 taken transversely to longitudinal axis 13 to illustrate one embodiment of an actuating member 24. Wall 18 extends about lumen 20 and closes it from the exterior of body 12. A number of passages 22 are formed in wall 18 and each are sized to receive an actuating member 24 therethrough. Although three actuating merjibers 24 are shown, it is also contemplated that one, two, or four or more <img file="WO2005025645A2_D0001.tif" /> members 24 can be provided. Actuating members 24 extend from a distal e-jid thereof adjacent distal end 14 of catheter 10 to a proximal end coupled to an ac uator, as discussed further below. i In the illustrated embodiment, actuating members 24 extend through respective ones of enlarged portions 26 of wall 18. Enlarged portions 26 project into lumen 20 from inner surface 30 of wall 18, and provide a region of increased wall thickness to accommodate the insertion of the actuating members 24 in wall 18. Actuating members 24 can be in the form of a wire, string, cable, tendon, rod, linkage, spring, or bar, for example. Actuating members 24 can be made from stainless steel, titanium, polymer, shape memory material, or other suitable material. Actuating members 24 can be coated with anti-bacterial agents and/or lubricious material to facilitate movement in wall 18. In other embodiments it is contemplated that one or more actuating members 24 can extend through lumen 20. Actuating members 24 extend proximally from a. location adjacent distal end 14 and are coupled with an actuator at their proximal ends. It is contemplated that the distal ends of actuating members 24 can be positioned proximally of ports 16, distally of ports 16, or along ports 16. The actuator is positioned along a proximal portion of catheter 10 and located outside the body of the patient so that the distal portion of catheter 10 can be remotely manipulated with the actuator mechanism to selectively open and close ports 16. In locations where actuating members 24 enter and/or exit the catheter body, the locations can be sealed and treated to prevent fluid leakage and infection. One embodiment of an actuator comprising an actuating mechanism with actuating members 24 is shown in Fig. 5 with a longitudinal cross-section through actuator 50. Actuator 50 is positioned about catheter bocly 12 and includes a hub 62 engageable with a slide-lock mechanism 52. Hub 62 includes a central passage 64 for receiving a portion of slide-lock mechanism 52 arid catheter body 12. Hub 62 further includes a distal tapered portion 68, and is fijtedly secured to catheter body 12. Slide lock mechanism 52 includes a proximal portion 54 which can be manually gripped or gripped with a tool to facilitate displacing slide-lock mechanism 50 axially relative to catheter body 12 and hub 62. Slide-lock mechanism 52 further includes a distal portion 56 extending into hub passage 64 and about catheter body 12. Distal portion 56 includes an engagement member 60 at a distal end thereof for engagement with proximal ends 25 of actuating members 24. A number of locking surfaces 58 are formed along the length of distal portion 56 between locking member 66 and proximal portion 54. Hub 62 includes locking member 66 to engage locking surfaces 58 with sufficient force at any one of a number of positions along locking surfaces 58 and maintain slide-lock mechanism 52 at the corresponding position relative to hub 62. Locking member 66 is sufficiently resilient so that locking member 66 can be moved along locking surface 58 to adjust a positioning of slide-lock mechanism 52 relative to hub 62. Wall 18 of catheter 10 can be manipulated by displacing slide-lock mechanism 52, and thus actuating members 24, proximally and axially relative to hub 60 and catheter body 12. The actuating members 24 pull on the portions of wall 18 adjacent ports 16 to open ports 16. Ports 16 can be closed by displacing slide-lock mechanism 52, and thus actuating members 24, distally and axially relative to hub 62 and catheter body 12. Locking member 66 engages slide-lock mechanism 52 to maintain ports 16 in either of the open and closed positions until sufficient force is applied to axially displace slide-lock mechanism 52 relative to hub 62. The actuating mechanism can further include one or more springs or other biasing members to facilitate maintaining ports 16 in either of the open or closed positions. Another embodiment of an actuator 150 useable -with the actuating system of catheter 10 is shown in Figs. 6 and 7. Actuator 150 includes a hub 162 and a slide-lock mechanism 152. Slide lock mechanism 152 includes a proximal portion 154 for gripping by the user, and a distal portion 156 extending into passage 166 of hub 162. Actuating members 24 are secured to distal portion 156. Hub 162 includes locking surfaces formed by a pair of receptacles 170 formed therein in communication with passage 166. Locking members 158 extend from distal portion 156 and into corresponding ones of the receptacles 170. Receptacles 170 each include a proximal offset portion 172 and a distal offset portion 174. To position and maintain ports 16 in a closed position, slide-lock mechanism 152 is distally advanced in hub 162 and rotated to position locking members 158 in distal offset portions 174. To position and maintain ports 16 in an open position, slide-lock mechanism 152 is proximally withdrawn from hub 162 and rotated to position locking members 158 in proximal offset portions 172. Positioning of the locking members 158 in the offset portions prevents axial movement of slide-lock mechanism 152 relative to hub 162. It is also contemplated that offset portions for receptacle 170 can be provided between proximal and distal offset portions 172, 174 to provide for variability in the degree of opening of ports 16 and for changes in the physical properties of catheter body 12 and actuating members 24 over time. Another embodiment of an actuator 250 for an actuating mechanism for catheter 10 is shown in Figs. 8 and 9. Actuator 250 includes a hub 262 and a slide- lock mechanism 252. Slide lock mechanism 252 includes one or more locking members 254 extending therefrom. Actuating members 24 are secured to slide- lock mechanism 252 and movable therewith. Hub 262 includes a pair of opposite end portions 263 engageable to catheter body 12. Hub 262 further includes a pair of opposite slotted ports 264 and a pair of opposite sidewalls 265 extending between the opposite slotted ports 264. At least one receptacle 266 extends through at least one of the sidewalls 265. Receptacle 266 includes an offset portion 268 at a proximal end thereof. Slide-lock mechanism 252 is positioned between sidewalls 265 and moveable therebetween axially along catheter body 12. Locking member 254 extends into receptacle 266, and is movable therealong with movement of slide- lock mechanism 252 for positioning into offset portion 268 to secure ports 16 in an open condition. A second distal offset receptacle portion (not shown) can be provided to secure ports 16 in a closed condition, and offset portions can be provided along the length of receptacle 266 to accommodate variation in opening of ports 16 and the physical properties of catheter body 12 and actuating members 24. Another embodiment actuator 350 is shown in Figs. 10 and 11. In Figs. 10 and 11 the proximal end of catheter 10 is shown with a cuff 40 positionable below the skin level to assist in maintaining the catheter in the patient and prevent leakage around catheter 10. The proximal end of catheter 10 further includes a luer lock fitting 42. Actuator 350 includes a tube member 352 through which actuating member 24 extends. Tube member 352 extends transversely from a side of a distal portion 43 of fitting 42. The portion of tube member 352 nearest to hub 43 includes a plastic material, such as silicone glue, therein to serve as a seal around the actuating member 24. Actuating member 24 extends through tube member 352 and the plastic material to an enlarged end member 26 at the proximal end of actuating member 24. End member 26 is attached to tube member 352 and assures that actuating member 24 moves with the expansion and compression of tube member 352. Tube member 352 includes an accoxdion-like shape along its length with a wall that folds upon itself to allow expansion and contraction of the length of tube member 352. Tube member 352 can be glued or sealed at each end to prevent contamination. Figs. 12-14 illustrate various views of a distal portion of a catheter according to another embodiment. Catheter 410 includes a catheter body 412 with a central lumen 420. The distal end 413 of body 4-12 is sealed with a cap 414, which may be integral with body 412 or a separate member sealingly engaged thereto. Body 412 includes a wall 418 extending about lumen 420. Wall 418 includes one or more ports 416, which can be elongated slits or gills as discussed above with respect to catheter 10. Wall 418 further includes an inflation lumen 422 formed therein for delivery of a fluid, such as saline, air, gas, or other suitable fluid, to inflate an enlargement member 428. Enlargement member 428 is positioned in lumen 420, and is shown in a reduced-size configuration in Fig. 12 and an enlarged configuration in Figs. 13 and 14. Enlargement member 428 can be in the form of a balloon, bag, bladder, diaphragm or other device capable of opening and closing ports 416 as it is enlarged and reduced. End cap 414 and distal end 413 define a pocket 424 therebetween. Inflation lumen 422 is in fluid communication with pocket 424 to deliver fluid thereto. An inflation tube or stem 426 extends through lumen 420 from distal end 413. Stem 426 includes an internal passage in fluid communication with pocket 424 and enlargement member 428. Accordingly, fluid can be moved through inflation lumen 422 to pocket 424 and through stem 426 to enlargement member 428 to selectively enlarge and reduce enlargement member 428. One or more arms 430 extend between enlargement member 428 and an inner surface 419 of wall 418 at wall portions 432 adjacent ports 416. As shown in Fig. 14, an arm 430 is provided between each port 416. As enlargement member 428 is enlarged, arms 430 push outwardly to radially deform wall portions 432 of wall 418 and effecting separation of the adjacent wall portions

0005432 and opening each port 416. In the illustrated embodiment, there are provided three arms 430, three ports 416, and three wall portions 432 between adjacent ones of the ports 416. Arms 430 space wall portions 432 from the enlarged enlargement member 428 to provide a path for blood flow through the open ports 416 and about the enlarged enlargement member 428 into lumen 420. When the fluid is removed from enlargement member 428, its size reduces and arms 430 pull wall portions 432 into alignment with catheter body 412, closing ports 416 to prevent flow therethrough. To effect a positive force between adjacent sides of wall portions 432 to sealingly close ports 416, a negative pressure can be imparted to enlargement member 428, drawing wall portions 432 radially inwardly in contact with one another. Other configurations for ports 416 are also contemplated, including a single port 416 with a pair of wall portions 432 positioned adjacent to the sides thereof. In another embodiment, a pair of ports 416 are provided at opposite sides of body 412, and a pair of wall portions 432 are centrally spaced between the opposite ports 416. In a further embodiment, four or more ports 416 with a corresponding number of wall portions positioned between adjacent ports are contemplated. Any one or all of the wall portions of the embodiments may be provided with an arm extending between the wall portion and the enlargement member. Other configurations are also contemplated for delivering fluid to enlarge enlargement member 428 are contemplated. For example, one or more of the arms 430 can include a passage to deliver fluid to enlargement member 428. In another embodiment, enlargement member 428 is in direct fluid communication with enlargement lumen 422. The catheter embodiment in Figs. 12-14 utilizes pneumatic or hydraulic means to manipulate wall 418 of catheter 410 to selectively open and close ports 416. When ports 416 are closed, blood flow is prevented from entering lumen 420 and a lock solution can be retained in lumen 420 to prevent coagulation. Other variations for stem 426 and arms 430 are also contemplated. For example, stem 426 can include a bellows, accordion-like, or other suitable configuration that is axially expandable and compressible, or otherwise axially movable, to reposition stem 426 in lumen 420. Arms 430 can include a wire form or other structure pivotally connected to stem 426 and wall portions 432. When stem 426 is in a first axial configuration and positioning relative to wall portions 432, the arms 430 are angled between stem 426 and wall portions 432 to maintain ports 416 in a closed condition. When stem 426 is moved to a second axial configuration, the ends of arms 430 connected to stem 426 move therewith, and as the arms become more orthogonally oriented to stem 426, the arms 430 push radially outwardly on wall portions 432 to open ports 416. In still another embodiment arms 430 expand along their axes between stem 426 and wall portions 432 to move wall portions 432 away from one another to open ports 416. Arms 430 are collapsible along their axes to move wall portions 432 toward one another and close ports 416. In this embodiment, stem 426 can be non-expandable and/or non-movable. In one form, arms 430 include an accordion or bellows-like configuration along their length. In another form, arms 430 include a balloon-like configuration and are at least axially expandable, and can also be radially expandable. Figs. 15 and 16 show a distal portion of another embodiment catheter. In Fig. 15 the distal ports of the catheter are in a closed condition, and in Fig. 16 the distal ports are in an open condition. Catheter 510 includes a catheter body 512 with a central lumen 520 defined by a first wall 518. The distal end 513 of first wall 518 is openable to allow fluid to flow into lumen 520, and closeable to prevent fluid flow into lumen 520. First wall 518 includes one or more ports 516, which can be elongated slits or gills that extend to distal end 513. Adjacent ones of the ports 516 are separated by wall portions 519 extending therebetween. A second wall 522 extends through lumen 520 and forms a second lumen 524. Second lumen 524 opens at distal end 526 of second wall 522. Second wall 522 includes a number of end members 528 that are normally biased to the closed position to prevent fluid flow from entering second lumen 524. Pressure from fluid in second lumen 524 causes end members 528 to move away from one another and separate, allowing fluid egress from lumen 524 through distal end 526. Other embodiments contemplate that lumen 524 is not used for blood flow. Still other embodiments contemplate that catheter 510 is provided without a lumen 524. Second wall 522 further includes an enlargement member 530 formed therearound proximally of end members 528. Enlargement member 530 is received in lumen 520, and has a collapsed or reduced-size configuration, as shown in Fig. 15, and an enlarged or expanded configuration, as shown in Fig. 16. Second wall 522 can include an inflation lumen (not shown) in fluid communication with an interior of enlargement member 530 for delivery and removal of fluid from enlargement member 530. The fluid can be saline, air, gas, or other suitable fluid, to inflate or enlarge enlargement member 530. Enlargement member 530 can be in the form of a balloon, bag, bladder, diaphragm or other device capable of opening and closing ports 516 as it is enlarged or reduced. When in the unexpanded condition of Fig. 15, adjacent ones of the wall portions 519 abut one another so that ports 516 are closed. Fluid flowing in second lumen 524 may exit lumen 524 through the distal end opening of second wall 522 provided the fluid pressure is sufficient to open distal end 526 by separating end members 528. If fluid ingress into lumen 520 is desired, fluid can be delivered to enlargement member 530 to cause it to enlarge or expand. As it expands, it acts on wall portions 519 to radially deform wall 518 and cause ports 516 to open as wall portion 519 separate. Arms 532 can be provided between enlargement member 530 and wall portions 519 to facilitate radial deformation of wall 518, assure active closing of ports 516, and prevent detachment of wall portions 518 from enlargement member 530. Arms 532 attach wall portions 519 to enlargement member 530. In one embodiment, there is zero clearance between enlargement member 530 and wall portions 519, and fluid flow is directed through open ports 516 proximally of distal end 513. Arms 532 are provided with sufficient elasticity to span the differing radii of curvature between the distal ends of wall portions 519 and the enlarged enlargement member 530. In another embodiment, arms 532 maintain separation between the inner surface of wall 518 and enlargement member 530, facilitating fluid flow through the distal end opening of first wall 518 and also through the ports 516 between the adjacent wall portions 519. In the illustrated embodiment, arms 532 extend distally of the respective wall portions 519 and into contact with enlargement member 530. It is also contemplated that one or more of the arms 532 can also be located within lumen 520, and can include any configuration as discussed above with respect to arms 430. In the illustrated embodiment, there are provided three arms 532, three ports 516, and three wall portions 519 between adjacent ones of the ports 516. Wall portions 519 may or may not be spaced from the enlarged enlargement member 530. When enlargement member 530 is enlarged, the open ports 516 provide a path for blood flow therethrough and about the enlarged enlargement member 530 into lumen 520. When the fluid is removed from enlargement member 530, its size reduces and wall portions 519 collapse into alignment and abutting engagement with one another, closing ports 516 to prevent flow therethrough. In one embodiment, arms 532 can be engaged to enlargement member 530 and wall portions 519 to pull wall portions 519 to the closed condition. Arms 532 can assure a positive closure of ports 516 when enlargement member 530 is in its reduced size configuration. In another embodiment, wall portions 519 are naturally biased via a living hinge connection with wall 518 toward the closed condition. In a further embodiment, arms 532 can be secured to the distal ends of wall portion 519 at one end of each of the arms 532 and include an opposite end that rides or floats along enlargement member 530 as it is expanded and collapsed. In still another embodiment, arms 532 can expand along their axes between enlargement member 530 and wall portions 519 to move wall portions

0006519 away from one another to open ports 516 as fluid is delivered to arms 532. Arms 532 can be collapsible along their axes to move wall portions 519 toward one another and close ports 516. In this embodiment, enlargement portion 530 can be non-expandable or non-enlargeable. In one form, arms 532 include an accordion or bellows-like configuration along their length. In another form, arms 532 include a balloon-like configuration and are at least axially expandable, and can also be radially expandable. Other configurations for ports 516 are also contemplated, including a single port 516 with a pair of wall portions 519 positioned adjacent to the sides thereof. In another embodiment, a pair of ports 516 are provided at opposite sides of body 512, and a pair of wall portions 519 are centrally spaced between the opposite ports 516. In a further embodiment, four or more ports 516 with a corresponding number of wall portions are positioned between adjacent ports are contemplated. For any of the embodiments, one or more arms 532 may be provided between the enlargement member and one or more the wall portions, or no arms 532 are provided. The catheter embodiment in Figs. 15-16 utilizes pneumatic or hydraulic means to manipulate wall 518 of catheter 510 to selectively open and close ports 516. When ports 516 are closed, blood flow is prevented from entering lumen

0007520 and a lock solution can be retained in lumen 520 to prevent coagulation. Lock solution can also be maintained in lumen 524 to prevent coagulation. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. For example, for any embodiment catheter actuating mechanisms are contemplated that include micro-motors or other automatic or mechanical systems for opening and closing the fluid flow ports. All changes and modifications that come within the spirit of the invention are desired to be protected.