Abstract:
Systems, devices, and methods towards improved diagnosis and therapy in connection with central venous catheters (including PICC lines). Included among the many improvements broadly contemplated herein are: arrangements via which a venous catheter can move passively into position in central venous circulation; arrangements via which a catheter can be actively guided without the use of a needle or guide wire; arrangements via which a catheter can be packaged to facilitate easy, rapid, and positionally accurate deployment by medical personnel while maintaining device sterility; and arrangements via which a catheter tip can be imaged during and after insertion.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/794,051, filed on Apr. 21, 2006, the contents of which are incorporate herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to central venous catheters, e.g., as employed in patient care and cardiac CT angiography, and to equipment which relates to or provides support to the same. 
       BACKGROUND OF THE INVENTION 
       [0003]    The historical introduction of catheters provided a boon to numerous medical applications, especially in the sphere of cardiac applications, but room has continually existed for improvement in the structure and makeup of the catheters themselves as well as in the types of equipment and arrangements that might be used in conjunction with or in support of catheters. 
         [0004]    Generally, perennial problems have presented themselves in terms of how effectively a catheter can be deployed in and along a patient&#39;s vein, and how this might impact not only the comfort of the patient but also any medical risk that could be presented to the patient as a result. For instance, poor catheter design has long been associated with problems relating to the excessive distention of a vein or even the partial or total occlusion of blood flow. While the field thus does not lack for efforts to render ongoing improvements, many shortcomings do still exist. Other problems and challenges have been encountered in connection with matters literally and figuratively external to the deployment of a catheter, such as how to physically measure the deployment of a catheter, how to keep it or a surrounding region sufficiently sterile, and how to locate a catheter tip once deployed into a patient. 
         [0005]    By way of some specific catheter applications, the interior of coronary arteries and great vessels of the heart historically were imaged via X-Ray fluoroscopy, enhanced by injection of radio-opaque contrast fluids through arterial catheters. However, in recent years the introduction of multi-detector CT (MDCT) scanners has made it possible to create 3D images, nearly in real-time, not only of the inner lumen of great vessels and coronary arteries, but also of the anatomy of the surrounding cardiac structures. 
         [0006]    A further advantage of MDCT is that the internal walls of the coronary vessels, structures surrounding the vessels, and calcification of the coronary vessel walls can be imaged, whereas coronary arteriography only delineates the internal lumen of those arteries. It has been demonstrated that coronary arteries can be imaged by injecting contrast fluid (alternatively, “contrast medium”) into the peripheral venous circulation, typically through a short catheter placed in an accessible vein of the arm or hand. 
         [0007]    However, there are disadvantages inherent in coronary imaging via MDCT using the peripheral intravenous injection of contrast. Significant among these is the loss of image quality in view of the varying time delay and dilution of contrast as it travels the venous circulation to the heart and subsequently mixes with blood in the pulmonary circulation before reaching the arterial side of the heart. As such, U.S. Pat. No. 6,442,415 (Bis et al.) addresses the use of coronary CT angiography (CTA) by means of arterial injection of contrast into the aortic root. Although this method has been shown to produce outstanding images of the coronaries under MDCT, the procedure necessitates the introduction of an arterial catheter in the sterile environment of a cardiac catheterization lab, under the guidance of a skilled interventional cardiologist, radiologist or vascular surgeon. 
         [0008]    A method that is less invasive than arterial catheterization of the heart, yet more invasive than an IV peripheral needle injection, is a central venous catheter approach. Here, the coronary arteries can be imaged by MDCT by introducing a catheter into the central venous circulation, preferably through the superior vena cava into the chambers of the right heart, or alternatively, into the cardiac venous circulation via the coronary sinus. 
         [0009]    The injection of contrast here presents two distinct advantages over peripheral intravenous injection. First, the contrast arrives in the right heart in more concentrated form before its journey through the pulmonary circulation and then into the left heart, which in turn feeds both the arterial circulation and the coronary arteries. Second, the time delay and build-up of contrast fluid in the arm is eliminated when an intravenous injection is made through a peripheral vein in the arm. Normally such a build-up of contrast is sometimes responsible for excess image artifact and X-Ray scatter, especially in the right heart, which degrades the images of the heart and coronary arteries. 
         [0010]    As a method for injecting fluids into the central venous circulation, central catheters have long been known. These are placed into veins in the chest or neck. These have been gradually replaced by PICC (peripherally inserted central catheter) technology. PICC lines are flexible catheters that are inserted typically through a vein in the arm into the central venous circulation near the heart. To aid in the catheter placement, a stiff needle or guide wire is provided in the lumen of the flexible catheter. Under the guidance of a fluoroscope (or an ultrasonic imaging device), the combination guide wire and catheter is typically threaded through the vessel into the central vena cava. Once in place, the needle or guide wire is removed, leaving the flexible catheter in place with the distal tip properly positioned for injection of fluid. These catheters can be left in place for days to months for the low flow-rate infusion of medication into the patient, and/or for sampling blood in patients with veins that have been compromised by disease or by the corrosive effects of chemotherapeutic drugs. 
         [0011]    However, despite the advances hitherto made with PICC technology, there is tremendous room for improvement in the realm of injecting higher doses of contrast medium, at higher rates, into central venous circulation during the relatively short time-frame of a coronary angiographic procedure. 
         [0012]    In view of the foregoing, numerous needs have been recognized in connection with developing and effecting improvements in the general sphere of coronary and venous imaging and particularly in connection with the equipment and methods employed. 
       SUMMARY OF THE INVENTION 
       [0013]    Broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, are systems, devices, and methods for improved diagnosis and therapy with central venous catheters and PICC lines. 
         [0014]    Included among the many improvements broadly contemplated herein are: 
         [0015]    arrangements via which the venous catheter can move passively into position in the central venous circulation; 
         [0016]    arrangements via which a flexible venous catheter can be actively guided from the insertion point in a peripheral vein into the final location of the tip in the central venous circulation, without the use of a needle or guide wire; 
         [0017]    arrangements via which a catheter can be packaged to facilitate easy, rapid, and positionally accurate deployment by medical personnel of average skill, while maintaining device sterility; and 
         [0018]    Arrangements via which a catheter tip can be imaged during and after insertion. 
         [0019]    In summary, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter comprising: a catheter body; and an arrangement for promoting movement of the catheter body within a blood vessel; the arrangement for promoting movement comprising at least one entraining arrangement for entraining blood flow and urging the catheter body forward within a blood vessel. 
         [0020]    Further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter comprising: a catheter body; and an arrangement for promoting movement of the catheter body within a blood vessel; the arrangement for promoting movement comprising at least one propulsion arrangement for applying a force from outside the catheter to urge the catheter body forward within a blood vessel. 
         [0021]    Additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter comprising: a catheter body; and an arrangement for promoting movement of the catheter body within a blood vessel; the arrangement for promoting movement comprising an arrangement for assisting forward movement of the catheter body via physical engagement with a blood vessel. 
         [0022]    Yet further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter comprising: a catheter body; and an arrangement for promoting movement of the catheter body within a blood vessel; the arrangement for promoting movement comprising a wound or braided portion for imparting increased flexibility to the catheter body. 
         [0023]    Still further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter system comprising: a catheter body; and an arrangement for selectably varying a stiffness of the catheter body. 
         [0024]    Additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter system comprising: a catheter body; and an arrangement for providing a propulsion force to promote movement of the catheter body within a blood vessel; the arrangement for providing a propulsion force comprising an arrangement for providing fluid to a blood vessel; the arrangement for providing fluid being configured to feed the catheter body to a blood vessel simultaneously with providing fluid to a blood vessel. 
         [0025]    Furthermore, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter system comprising: a catheter body; the catheter body comprising a plurality of minor conduits; a propulsion arrangement configured for selectively and separately providing fluid to each of the minor conduits to promote selective steering of the catheter body. 
         [0026]    Moreover, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter system comprising: a catheter; a sterile container which contains the catheter; the sterile container comprising an opening for surrounding an entry point on a patient&#39;s body. 
         [0027]    Still additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, catheter system comprising: a catheter; a container which contains the catheter; and a measuring arrangement for measuring a length of the catheter which exits the container, at least a portion of the measuring arrangement being disposed on the container. 
         [0028]    Furthermore, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter measuring system comprising: a measuring wheel for measuring a length; and a cutting arrangement for cutting catheter; and a mounting arrangement which supports both the measuring wheel and the cutting arrangement. 
         [0029]    Moreover, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a catheter body; an arrangement for facilitating location of the catheter body, the arrangement for facilitating location being disposed on the catheter body; and a tracking arrangement configured for tracking the arrangement for facilitating location when the catheter body is disposed within a patient&#39;s body. 
         [0030]    Yet even further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of manipulating a catheter, the method comprising: providing a catheter body; and selectably varying a stiffness of the catheter body. 
         [0031]    Still even further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of manipulating a catheter, the method comprising: providing a catheter body; providing a propulsion force to promote movement of the catheter body within a blood vessel; the step of providing a propulsion force comprising providing fluid to a blood vessel; and feeding the catheter body to a blood vessel simultaneously with providing fluid to a blood vessel. 
         [0032]    Yet even additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of manipulating a catheter, the method comprising: providing a catheter body, the catheter body comprising a plurality of minor conduits; selectively and separately providing fluid to each of the minor conduits to promote selective steering of the catheter body. 
         [0033]    Still even additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of manipulating a catheter, the method comprising: providing a sterile container which contains a catheter; surrounding and securing a portion of the sterile container about an entry point on a patient&#39;s body; and deploying the catheter into the patient&#39;s body. 
         [0034]    Furthermore, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of manipulating a catheter, the method comprising: providing a sterile container which contains a catheter; and measuring a length of catheter which exits the container with a measuring arrangement at least partly disposed on the container. 
         [0035]    Moreover, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a method of tracking catheter, the method comprising: providing a catheter body; disposing on the catheter body an arrangement for facilitating location of the catheter body; and tracking the arrangement for facilitating location when the catheter body is disposed within a patient&#39;s body. 
         [0036]    The novel features which are considered characteristic of the present invention are set forth here below. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]      FIG. 1A  illustrates a “passively guided” catheter of a first configuration. 
           [0038]      FIG. 1B  illustrates a “passively guided” catheter of a second configuration. 
           [0039]      FIG. 1C  illustrates a “passively guided” catheter of a third configuration. 
           [0040]      FIG. 2A  illustrates, in cross-sectional view, an “actively guided” catheter, involving reverse flow propulsion, of a first configuration. 
           [0041]      FIG. 2B  illustrates, in cross-sectional view, an “actively guided” catheter, involving reverse flow propulsion, of a second configuration. 
           [0042]      FIG. 2C  illustrates, in a radial cross-sectional view taken along line II-II, a portion of the catheter shown in  FIG. 2B . 
           [0043]      FIG. 2D  illustrates, in cross-sectional view, an “actively guided” catheter, involving reverse flow propulsion, of a third configuration. 
           [0044]      FIG. 3A  illustrates, in cross-sectional view, an “actively guided” catheter, involving a divided outer annular chamber. 
           [0045]      FIG. 3B  illustrates, in a radial cross-sectional view, a portion of the catheter shown in  FIG. 3A  along with a schematically illustrated control element. 
           [0046]      FIG. 3C  illustrates a distal end of the catheter shown in  FIG. 3A . 
           [0047]      FIG. 4A  illustrates an “actively guided” catheter involving deformable edges, in a first position. 
           [0048]      FIG. 4B  illustrates an “actively guided” catheter involving deformable edges, in a second position. 
           [0049]      FIG. 5  illustrates an additional catheter embodiment involving reverse jet-flow. 
           [0050]      FIG. 6A  illustrates an “actively guided” catheter involving a “rotary millipede” configuration, in a first position. 
           [0051]      FIG. 6B  illustrates an “actively guided” catheter involving a “rotary millipede” configuration, in a second position. 
           [0052]      FIG. 6C  illustrates an “actively guided” catheter involving a “rotary millipede” configuration, in a third position. 
           [0053]      FIG. 7  illustrates an “actively guided” catheter involving an “axial millipede” configuration. 
           [0054]      FIG. 8  illustrates an “actively guided” catheter involving a “flow assisted” configuration. 
           [0055]      FIG. 9  illustrates an “actively guided” catheter involving an “everting” configuration. 
           [0056]      FIG. 10  illustrates an “actively guided” catheter involving a “variable stiffness” configuration. 
           [0057]      FIG. 11A  illustrates a an “actively guided” torque catheter with braiding. 
           [0058]      FIGS. 11B and 11C  respectively illustrate variant catheter tips that may be employed with the catheter of  FIG. 11A . 
           [0059]      FIG. 11D  provides a close-up view of a catheter portion, with an alternative coiled component that could be employed in the catheter shown in  FIG. 11A   
           [0060]      FIG. 11E  provides a close-up view of a catheter portion having cross-braiding as shown in  FIG. 11A . 
           [0061]      FIGS. 12A-12E  show successive views of an “actively guided” catheter involving a double-balloon configuration, in various positions in a catheter insertion process. 
           [0062]      FIG. 13A  shows a catheter bag of a first configuration. 
           [0063]      FIG. 13B  shows a catheter bag of a second configuration. 
           [0064]      FIG. 13C  shows a catheter bag of a third configuration. 
           [0065]      FIG. 14A  shows a catheter dispensing arrangement. 
           [0066]      FIG. 14B  shows a measuring wheel for use in the dispensing arrangement of  FIG. 14A . 
           [0067]      FIG. 14C  shows another measuring wheel configuration. 
           [0068]      FIG. 15A  shows a catheter arrangement which facilitates catheter tip location. 
           [0069]      FIG. 15B  shows a hand-held locator for use with the arrangement of  FIG. 15A . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0070]    Generally, improvements to catheters are contemplated herein in two general areas: “passively” guided catheters and “actively” guided catheters. The former tend to involve those catheters that are able to be deployed along a patient&#39;s vein either partly or wholly by virtue of any assistive forces provided by blood flow. The latter tend to involve those catheters that at least partly involve some external applied force to help deploy a catheter along a patient&#39;s vein. When deployed, catheters may deliver fluids such as saline solution, contrast solution and/or medication as variously discussed herebelow, or be used to withdraw and optionally redeliver fluids, for example blood, from the patient for testing or treatment purposes. If not otherwise stated herebelow, it should be understood that to the extent contrast delivery is discussed herebelow, medication delivery is also contemplated in the same posture, and vice versa. 
         [0071]    Passively guided catheters are known, but are in great need of improvement. One conventional arrangement employing blood flow to guide catheters towards a heart is the “Swann-Ganz” balloon catheter. This device requires a separate lumen within the catheter, which allows the passage of air to inflate a balloon on the distal tip. As the catheter approaches the pulmonary artery, it is guided into the right atrium of the heart by the entrainment of blood flowing behind the balloon. A primary disadvantage of this catheter is that a dedicated arrangement for inflating the balloon is needed. 
         [0072]    In accordance with a preferred embodiment of the present invention, there is broadly contemplated an arrangement wherein at the distal end of a catheter an entraining arrangement, for “capturing” blood flow to help “pull” the distal catheter tip (and by extension the entire catheter) along, is provided. More particularly, a dedicated arrangement for “inflating” or even just deploying such an entraining arrangement is not needed. 
         [0073]    As shown in  FIGS. 1A-1C , several arrangements in this posture are conceivable.  FIG. 1A  shows catheter  104  within walls of a blood vessel  102  where an outer sheath  106  can be retracted to permit a “parachute”  108  or analogous device (e.g., a polymer material with elastic or string segments extending therefrom) to release, and then entrain a portion of blood flow b. As can be appreciated, the force of blood flow will “pull” along the parachute  108  and hence catheter  104 ; this can be sufficient for propelling catheter  104  along the direction of blood flow b but could also conceivably be supplemented by an “active” propelling arrangement (conceivably one of those described in further detail here below). 
         [0074]      FIG. 1B  illustrates a variant embodiment where sheath  106  can be pulled back to expose wings or flaps  110  sufficient to “capture” and entrain blood flow. These can expand when the sheath is retracted and be caught by blood flow b and be forced outwardly away from the body of catheter  104 . Alternatively, wings/flaps  110  can be essentially rigid and a sheath might not be needed. 
         [0075]      FIG. 1C , for its part, illustrates yet another variant where a shroud  112  with perforations ( 114 ) “caps” distal end of catheter  104 . Preferably, the “solid” surface area of shroud  112  will be sufficient as to entrain blood flow to a degree sufficient for pulling along the catheter  112 , while perforations  114  may be of such a distribution and number as to reduce the risk of blood vessel occlusion and/or to act as a “damper” on the velocity with which the catheter  112  propagates along the blood vessel. While the use of an outer sheath may be desirable here, it may not be necessary. 
         [0076]    By way of providing a further “assist” to the arrangements shown in  FIGS. 1A-1C  for “passively” propagating a catheter along a blood vessel, especially if a patient&#39;s blood flow may not be sufficiently strong to move the “entraining elements” (e.g., parachute, wings/flaps or shroud) forward, it is conceivable to pump saline solution into the blood vessel from an external source. The momentum of the injected saline solution will thus help drive the “entraining” elements and the catheter tip forward in the vessel. The injected saline solution also has the benefit of more fully filling or distending the blood vessel. 
         [0077]    The disclosure now turns to a discussion of several “active” or “actively guided” catheters broadly contemplated in accordance with embodiments of the present invention. Here, catheters more or less rely upon force applied or urged from an external source (e.g., from the injection of saline solution) in order to propagate through a patient&#39;s blood vessel. Again, this would appear to be particularly favorable in the context of patients lacking strong blood flow. 
         [0078]      FIG. 2A  illustrates, in cross-sectional view within vessel  202 , a catheter  204  that includes two co-axial and generally concentric tubular or annular structures. Inner tube  204   a  is configured for accepting and propagating contrast medium or other fluid (such as medication) to be injected into or towards the “final site” within the patient&#39;s body, while outer annular tube  204   b  is configured for accepting and propagating saline solution by way not only of providing a “flush” but also propelling the catheter  204  forward through the patient&#39;s blood vessel in a manner described here below. 
         [0079]    As shown, contrast flow c takes place through inner tube  204   a . Prior to propagating contrast fluid, however, catheter  204  will preferably be propelled through the vessel  202  to the desired site. As shown, this may be accomplished by propagating fluid (e.g. a flow of saline solutions) through outer annular tube  204   b , whereby at a distal end of catheter  204  the annular tube  204   b  flares so as to turn back about 180 degrees ( 209 . Accordingly, any saline solution or other fluid propagated there through will cause the distal end of catheter  204 , and thus catheter  204 , itself, to propagate along the direction of blood flow b. Also, during the contrast injection, the rearward flow of saline solution might help create a minor “turbulence” that can assist in the mixing of contrast medium and blood, to optionally allow for a uniform distribution of contrast medium, provide a tighter bolus and/or a saline “chaser” for the contrast. 
         [0080]      FIGS. 2B and 2C  illustrate an alternative arrangement, with  FIG. 2C  being an end-on cross-sectional view of the catheter  204  of  FIG. 2B . As shown, catheter  204  may include two tubes that are nested but not concentric. Major tube  204   c  may be configured for carrying the flow c of contrast medium, while minor tube  204   d  may be configured for carrying the flow s of saline solution. By way of a similar principle as in the embodiment of  FIG. 2A , minor tube  204   d  may be redirected in a 180 degree direction ( 211 ) at a distal end of catheter  204  so that saline flow s may have the effect of propagating catheter  204  forward. 
         [0081]      FIG. 2D  illustrates yet another variant embodiment along the lines of the arrangements shown in  FIGS. 2A-2C . Here, catheter  204  may have at a distal end thereof one or more redirecting appurtenances  213  (mounted to catheter  204  itself in a manner not illustrated) that accept contrast or saline flow and redirect the same in a “reverse” direction with respect to the blood flow b, to thereby propel catheter  204  forward. The ratio of forward to reverse thrust is controlled by the size and geometry of the appurtenances  213  and associated openings. Saline is preferably used during positioning of the catheter  204  and contrast is delivered once catheter  204  is in place for imaging. 
         [0082]    In one advantageous refinement, the central opening amidst appurtenances  213  can be of a design that opens more widely under sufficient pressure (e.g., so that when contrast is delivered, the opening becomes wider). Alternatively, the central opening could be totally absent such that all flow can is rearwardly directed and forward thrust is maximized. Thus, when contrast is injected in such an instance, the rearward jetflow will efficiently mix the contrast with the blood. 
         [0083]      FIGS. 3A-3C  illustrate another example of an actively guided catheter in accordance with another embodiment of the present invention. As shown within a vessel  302 , catheter  304  may include an inner tubular portion  304   a  for directing contrast flow c, with an outer annular portion  304   b  for carrying saline solution flow s. As shown, the outer annular portion  304   b  may terminate at an end or wall portion  311  at the distal end of catheter  304 , thereby compelling saline solution to flow outward through holes or apertures  309 . 
         [0084]    As shown in  FIG. 3C , the holes or apertures  309  may preferably be shaped and oriented such that they promote reverse flow of saline solution to propel catheter  304  forward. Holes  309  may in fact have walls that are specifically angled to promote the desired reverse flow. 
         [0085]    As shown in  FIG. 3B , outer annular portion  304   b  may be divided into a plurality of longitudinal chambers (e.g., three in number,  313 / a/b/c /), separated by membranes or walls  314 . In accordance with a preferred embodiment, saline solution may be administered to these three chambers  313   a/b/c / separately, governed by a main control  315  with corresponding individual controls  315   a/b/c . In this way, such that by regulating the relative proportions of saline solution propagating through each of the chambers  313   a/b/c , it becomes possible to “steer” the catheter  304 , especially if it is necessary to move the catheter through tortuous vessel portions. Pumps that operate two or more syringes simultaneously are well known in the medical arts. 
         [0086]    Preferably, catheter  304  may be externally coated with a hydrophilic coating to minimize tissue or vessel trauma, as well as to maintain a lubricious coating for improved mobility. 
         [0087]    The inner tubular portion, as shown, is configured to deliver contrast or medication to the region of interest. Preferably, inner tubular portion  304   a  is centered with respect to the overall structure of catheter  304 , but may also be disposed or “biased” towards one side of the catheter  304  or the other. Both tubes  304   a/b  and the walls/membranes  314  can be formed via essentially any suitable means, such as extrusion. 
         [0088]      FIGS. 4A and 4B  relate to a deployable “umbrella” or “deflector” end on a catheter. As shown in  FIG. 4A  in vessel  402 , distal end of catheter  404  preferably has turned edges  409  when initially deployed in a patient&#39;s blood vessel. These turned edges  409 , as may be inherently appreciated, will serve to capture and entrain a portion of blood flow b. As shown in  FIG. 4B , a suitably configured control wire or tube  411  may preferably be manipulated to transform these edges  409  into a straightened configuration. Preferably, the edges  409  will be formed of a material sufficiently flexible to undergo the transformation as just described, but sufficiently rigid to maintain a consistent “turned” configuration when being deployed. 
         [0089]    It should be understood that the embodiment illustrated in  FIGS. 4A and 4B  can be incorporable into an “actively guided” catheter and thus form a constituent portion thereof. Accordingly, the concept illustrated in  FIGS. 4A and 4B  can be incorporated, for instance, into the embodiments shown and contemplated in connection with  FIGS. 3A-3C , or with  FIGS. 2A-2D , or with any other “actively guided” catheter, as may be suitable or viable, discussed or contemplated herein. The embodiment illustrated in  FIGS. 4A and 4B  could similarly be incorporable into a “passively guided” catheter and form a constituent portion thereof. Thus, the concept illustrated in  FIGS. 4A and 4B  could be incorporated, for instance, into the embodiments shown and contemplated in connection with  FIGS. 1A-1C , or with any other “passively guided” catheter, as may be suitable or viable, discussed or contemplated herein. 
         [0090]    In a further variant, a retractable outer sheath could be used to initially cover the edges  409 . 
         [0091]      FIG. 5  illustrates a catheter  504  (in vessel  502 ) with a terminal cap or plate  509  which directs fluid in a reverse direction. Here, an injector preferably injects fluid down the catheter  504  as the catheter  504  is inserted through vessel  502 . The cap or plate  509  has a rearwardly directed structure as shown to provide reverse fluid flow. In addition, the fluid distends the vein, making insertion easier. The cap or plate  509  does not have to have a significant backward component for there to be a benefit from filling and distending the vein, as mentioned above. 
         [0092]    A “rotary millipede” arrangement is contemplated in connection with  FIGS. 6A-6C . As shown in vessel  602 , catheter  604  may include multiple sets  609   a/b/c  of bristles or other soft physical protuberances extending radially away, and in a general proximal direction, from the catheter body. The sets of bristles (e.g., three sets) may be distributed evenly about the circumference of catheter  604  (e.g. 120 degrees apart in the case of 3 sets of bristles). The bristles  609   a/b/c  are preferably of such a length as to be extendable to the walls of vessel  602 . Each set  609   a/b/c  preferably includes subsets of bristles angled clockwise and counter clockwise with respect to the axis of the catheter. Essentially, rotary motion of the catheter  604  pushes it forward in the vessel. This can be understood by looking at  FIGS. 6   b  and  6   c . When rotated clockwise in  6   b , the bristles that were angled in the clockwise direction have slightly increased friction against the vessel wall and so are straightened out, moving the catheter forward. The bristles angled counter clockwise slide over the vessel wall. When the direction of rotation is reversed, the counter-clockwise angled bristles straighten out, again pushing the catheter forward and the clockwise oriented bristles simply slide over the vessel  602 . A similar phenomenon would occur at bristle sets  609   b  &amp;  609   c.    
         [0093]    Alternatively,  FIG. 7  shows an “axial millipede” arrangement. Here, in vessel  702 , an inner member  704  of catheter  704  is slidingly reciprocable with respect to an annular outer member  704   b  concentric thereto. Inner member  704   a  and outer member  704   b  each may have soft bristles or other physical protuberances  709 / 711 , respectively, as shown. Bristles  709 / 711  are extendable to the inner wall of vessel  702 . As such, bristles  711  of outer member  704   b  can essentially serve as an anchor while inner member  704   a  moves forward and, likewise, bristles  709  of inner member  704   a  can serve as an anchor while outer member  704   b  moves forward. As such, bristles  709 / 711  are preferably sufficiently rigid as to enable such an anchoring effect, while are also sufficiently soft as to facilitate easy and painless retraction of the entire catheter  704  from a patient. In another variant, the bristles  709 / 711  may be absent, with the inner member  704   a  being very flexible with the outer member  704   b  being stiffer, whereby, the inner member  704   a  can be propelled forward via blood flow b (perhaps assistively with wings or another “passive” aid). 
         [0094]      FIG. 8  illustrates a “pump assisted” system in accordance with another embodiment of the present invention. Preferably, a reservoir (e.g., containing saline solution) and pump  819  will serve to pump saline solution into a vessel  802  via an injecting arrangement  821 . A catheter  804 , fed from a coil  823  or other sterile storage container that is attached to or integral with injecting arrangement  821 , preferably enters a patient through portion  825  of injection arrangement  821 . (Portion  825  is inserted into the patient&#39;s vessel in a manner similar to a current peripheral IV catheter, optionally a needle-over-catheter arrangement.) It will be appreciated that the incoming flow of saline solution through the narrow segment  825  into the vein will assist in pushing catheter  804  onward. 
         [0095]      FIG. 9  illustrates an “everting” catheter in accordance with an embodiment of the present invention. As shown, catheter  904  preferably has flexible walls configured for being disposed against walls of vessel  902 . An end portion  909  of catheter  904  will thus initially be disposed at vessel wall  902  at point p as indicated, essentially serving as an “anchor”. As the catheter  904  is advanced in the direction of the arrow, catheter  904  will essentially turn inside out so that an increasing length of catheter  904  is disposed against the walls of vessel. In this manner, catheter  904  will easily follow and conform to the natural contours of vessel  902 , which would be a huge advantage in the case of particularly tortuous vessels. By lying against the vessel walls, catheter  904  also protects the walls from dissection or abrasion. After delivering fluid (e.g., contrast or medication) through central lumen  904   a  desired, catheter  902  can be retracted in reverse. 
         [0096]    Optionally, the walls of catheter  904  can be formed from a biodegradable material that can be left in the vessel  902  permanently. Used in this manner, it can remain in the vessel  902  to assist in the future delivery of, e.g., drugs, genes, stem cells, or proteins to promote healing in vessels weakened by disease or repeated chemotherapy. In another variant, a biocompatible, but non-degradable “everting” catheter could be used as a permanent implant that would replace damaged blood vessel endothelium, similar to a stent or stent-graft. In this capacity as a prosthetic vessel lining, the catheter wall making contact with the vessel surface could also be coated with e.g., medications, cells, or proteins to promote healing, reduce thrombosis risk, and/or slow the process of diseased vessel wall remodeling. The outside catheter wall could also be coated with non-thrombogenic materials such as heparin to reduce the risk of clot formation. 
         [0097]    The eversion phenomenon described above could be “powered” by fluid pressure between the catheter walls (in annular space  904   b ), in accordance with a further variant. In this case, both ends of the catheter  904  would need to be outside the vein and a sliding seal could be provided at the entry point into vessel  902  Saline solution could be injected between the walls (into annular space  904   b ), to provide the fluid pressure. Alternatively, the fluid pressure could be minimal but still serve as a physical “buffer” between the catheter walls to reduce friction. 
         [0098]    In yet another variant, the everting effect described above could represent a way to push the catheter through the vein, and not form the wall of the catheter itself. In this case, the everting section would fold back shown as the catheter itself is pushed forward, but not touch the wall of vessel over its whole circumference. The everted section could then be withdrawn afterward or left in as part or the totality of the catheter. 
         [0099]      FIG. 10  illustrates a “variable stiffness” catheter  1004  in accordance with an embodiment of the present invention. As shown in vessel  1002 , a catheter  1004  may be controllably stiffened and/or relaxed via a stiffener arrangement  1009 . Through controllable stiffening, great ease could be involved in introducing catheter  1004  into vessel  1002 , while a higher stiffness can be maintained as needed to rapidly move through a straight vessel segment, and then be reduced for slow manipulation through tight curvatures encountered in tortuous small vessel branches. 
         [0100]    The stiffener arrangement  1009  could take on a wide variety of forms. For instance, it could involve an arrangement for placing the catheter in cold water to stiffen it for insertion, which would then soften at body temperature. Alternatively, the catheter could have a magnetic component (for example, two cross windings that behave like a ferro fluid) which would become more rigid in the presence of a magnetic field that would cause the two cross windings to attract and bind. In another variant, there could be wires in the catheter wall that become stiffer or more flexible in response to externally applied heat or current. Or, the catheter could be constructed with electro-active polymers (EAP&#39;s), whose stiffness is related to applied voltage or current. Overall, it will be appreciated that a wide variety of implementations are possible, with the common objective being an arrangement ( 1009 ) for controlling the stiffness of catheter  1004  as catheter  1004  is being moved into and through a body, the stiffness being variable to accommodate a variety of prospective conditions. 
         [0101]      FIG. 11A  shows in vessel  1102 , a polymer catheter  1104  with an outer sheath  1106 . This embodiment can be looked upon as improving upon a conventional torque angiography catheter, and thus is especially well-configured for traversing through tortuous vessels. (While torque catheters are normally designed to navigate through torturous vessels in arterial vasculature, broadly contemplated here is an advantageous arrangement for navigating, at the very least, in tortuous veins). 
         [0102]    Catheter  1106  may preferably involve a three-layer construction, including an inner layer of biocompatible polymer (capable of withstanding the forces of braiding, and which resists kinking during use) multiple filament cross-wound metallic or polymer braiding  1111  and a biocompatible polymer overcoat (not illustrated). The cross-wound braiding is preferably configured to provide torque to position the catheter tip to the selected body region. 
         [0103]    The outer sheath  1106  could be either over-molded through extrusion technology or applied by way of a shrink-wrap material. Either way may be appropriate for a given application at hand, although extrusion would appear to yield more favorable results. Extrusion materials could be custom-compounded to enhance softness, biocompatibility, and maneuverability. Optionally, a hydrophilic coating could be applied atop outer sheath  1106  to further enhance maneuverability and minimize tissue trauma. 
         [0104]      FIGS. 11B and 11C  illustrate optional shaped catheter tips  1113  and  1115 , respectively, similar to angiography catheters, for providing additional maneuverability for placement. 
         [0105]    As shown in  FIG. 11D , as an alternative to cross-wound braiding, a single filament  1112  could be wound around the inner tube layer of catheter  1104  to form a continuous coil; this can yield similar torque capability yet allow more inherent flexibility than a cross-wound braid. Particularly, due to a dramatically reduced winding pitch angle, there will be increased flexibility (particularly helpful in the context of less robust venous structure). 
         [0106]      FIG. 11E , for its part, provides a close-up view of a portion of catheter  1104  having the cross-braid configuration of  FIG. 11 . A. 
         [0107]      FIGS. 12A-12E  illustrate a “walking catheter” in accordance with an embodiment of the present invention. As shown in vessel  1202 , catheter  1204  preferably includes two lumens as defined by portions  1204   a  and  1204   b . Inner portion  1204   a  is preferably formed from elastic and outer annular portion  1204   b  is preferably formed from a more rigid material. A first balloon  1209  is in fluid communication with inner portion  1204   a  and a second balloon is in fluid communication with outer portion  1204   b . Balloons  1209 / 1211  are preferably separate from one another and are independently controlled via separate fluid paths. 
         [0108]      FIG. 12A  shows an initial state where both balloons  1209 / 1211  are uninflated. To advance catheter  1204 , balloon  1211  is preferably inflated as shown in  FIG. 12B , e.g. via saline solution. With balloon  1211  now fully inflated and serving as an anchor, further fluid then delivered to balloon  1211  will progress into inner portion  1204   a , whereby (uninflated) balloon  1209  is advanced forward as a result. Preferably, the elastic material of inner portion  1204   a  will be suitably configured to expand not radially but only longitudinally. 
         [0109]    At this point, balloon  1209  is preferably inflated as shown in  FIG. 12C , to ensure that the same will also now serve as an anchor. Continuing, as shown in  FIG. 12D , rear balloon  1211  is preferably deflated which then causes the same to advance toward the front balloon  1209 , as shown in  FIG. 12E ; here, the elastic material of inner portion  1204   a  is relieved of its tension. Upon then deflating front balloon  1209 , the process can restart as in  FIG. 12A . Each of the balloons  1209 / 1211  is independently operated to achieve this repeating sequence by which the entire catheter assembly advances through the vessel  1202 . 
         [0110]    Optionally, front balloon  1209  could be equipped with a pressure relief valve at is tip to open up beyond a given threshold pressure and permit fluid (e.g., contrast fluid) to progress onward into the vessel  1202 . Generally, to preclude occlusion of vessel  1202 , balloons  1209 / 1211  could have a cross-section that permits continued blood flow (e.g., a star-shaped cross-section). 
         [0111]    By way of a further alternative, instead of an elastic tube between the balloons  1209 / 1211 , a rolling diaphragm or the like could be provided that would expand longitudinally but not radially. The present invention, in accordance with various additional embodiments, further relates to equipment associated with or supportive of catheters. It should be understood that such equipment, as discussed here below and broadly contemplated herein in general, can be used with essentially any compatible catheter arrangement, including, as appropriate, any or all of the catheter arrangements described and contemplated hereinabove. 
         [0112]    As such, the disclosure now turns to various arrangements for maintaining the sterility of a central venous catheter while it is being deployed in a patient. 
         [0113]    Normally, if a long catheter such as a PICC needs to be inserted into a vein, it has to be kept sterile before insertion. Typically, this involves draping a significant area of the patient and patient support around the insertion site. 
         [0114]    In accordance with an embodiment of the present invention, the catheter line can essentially be kept inside a sterile container or package until it goes into the patient, so that the sterile field need not be much larger than is normally the case for a simple IV catheter (which typically involves just washing around the site). 
         [0115]      FIG. 13A  shows a catheter  1304  extending from hub  1352  in an elongated plastic bag  1354 . When the package is opened, flap portion  1355  can surround washed skin to create a sterile field on all sides around the entry point of catheter  1304  into a body. Tape can hold bag  1354  to washed skin at opening  1356 . 
         [0116]      FIG. 13B  shows a less elongated bag where a partial sterile field is created by taping bag  1366  to the skin at flap portion  1367  about opening  1368 . The catheter  1368  here extends from hub  1358  and “doubles back” within bag  1366  as shown 
         [0117]    In the variants shown in  FIGS. 13A and 13B  bags  1354 / 1356  could have some stiffness or rigidity to help support catheter  1304 / 1364 . Alternatively, as shown in  FIG. 13C , a bag  1376  (with opening  1378  and flap portion  1377 ) could crinkle up or gather as the catheter  1374  (extending from hub  1358 ) is inserted into a patient, while still maintaining a sterile field. 
         [0118]    It will be appreciated that with each of the variants shown in FIG.  13 A/B/C easy access is afforded to flush and fill the catheter line (e.g., with saline solution) before insertion into a patient if that is deemed to be needed. 
         [0119]    In terms of another type of support equipment for catheters, as shown in  FIG. 14A , a dispensing case or bag  1451  may include a luer hub  1455 . Hub  1455  preferably accommodates additional lengths of catheter  1404  from the outside as shown by the arrow. A filling valve  1453  may be provided for filling the case or bag  1451  with alcohol or antiseptic. While catheter  1404  is fed along, e.g., guide wheels or hubs  1457 , there is also preferably provided a rotary mount  1459  for accommodating a measuring wheel  1461  (see  FIG. 14B ). Measuring wheel  1461  may thus be selectively mounted on rotary mount  1459 , e.g. via a snap fit. 
         [0120]    Preferably, measuring wheel  1461  works in the manner of a surveyor wheel, to measure a linear distance to indicate the length of catheter  1402  that is payed out. Alternatively, wheel  1461  could be integrally fixed to mount  1459  initially. 
         [0121]    In yet another alternative, wheel  1461  could be completely separate from bag/case  1451  at all times and be used to measure a linear distance along the body of a patient, from the site of catheter insertion to a reasonable approximation of the desired location as “mapped” to the outside of the patient. In this manner, a needed length of catheter can be predetermined and then payed out and/or measured by essentially any suitable means and/or possibly by use of the same or another measuring wheel mounted onto case or bag  1451 . If the same measuring wheel is used, it can be used to “count down” a length of catheter fed therepast, starting with the original measurement determined from the outside of the patient&#39;s body. Alternatively, one measuring wheel can be used to measure on the patient and a second sterile wheel, used in the package, can be used to measure the catheter length. 
         [0122]      FIG. 14C  shows another variant. Particularly, a measuring wheel  1471  could be rotatably mounted on a holder  1473  that conveniently is configured to be held by a technician or doctor. Wheel  1471  can be rolled along the outside of a patient&#39;s body as just described, to get a close approximation of the length of catheter that subsequently will be needed. The catheter is then preferably fed, along a direction indicated by the horizontal arrow, through a “guillotine” or other cutting device  1475  mounted on holder  1473 . Using wheel  1471  to “count down” from the length just determined the catheter  1475  can be cut by cutting device  1475  when the wheel  1471  has reached “zero”. Alternatively, the measuring wheel or some other arrangement could be used to determine the desired length, and the package, for example that of  FIG. 13A , could have printed gradations on the outside to allow the catheter to be cut to the desired length before or as it is withdrawn from the package. 
         [0123]    An alternative to cutting the catheter to length is to leave the extra length coiled up in a compact arrangement similar to that shown in relation to  FIG. 8 . This is especially advantageous for contrast injections where the catheter will only be in place for a limited duration. 
         [0124]    Yet another scheme of catheter support is illustrated in  FIGS. 15A and 15B . As shown in  FIG. 15A , a catheter  1504  (e.g., a PICC catheter) may extend from an electrical line  1563 . At a distal end thereof, catheter  1504  also preferably includes a metal or magnetic tip  1565  which can be powered to activate an outside device for picking up the location of the tip within the patient&#39;s body (much like a “stud finder” used in construction applications). Accordingly, the location of tip  1565  within a patient&#39;s body could be continually monitored or verified, as could a final position of tip  1565  at a presumed site of interest. 
         [0125]      FIG. 15B  shows a handheld device  1567  that could be used to locate tip  1565 . Preferably, it is embodied by an easily “gripped” object (e.g., wand) that can be passed over a patient&#39;s body to find the tip  1565 . A light indicator  1569  (e.g. LED) could light up when the tip  1565  is found. A handle  1571  specifically configured for conveniently accommodating a technician or doctor&#39;s grip can be provided. As an alternative, tip  1565  could be located by an outside triangulation device such as a GPS. 
         [0126]    Generally, catheters, mechanical portions, balloons and other components as described hereinabove and broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, can be formed from essentially any of a very wide variety of plastics, metals or other materials generally used in the medical arts. Examples include, but are by no means limited to, polyurethanes, silicones, teflons, polyethylenes, copolymers, multi-layered structures, nitinol, stainless steel. 
         [0127]    Without further analysis, the foregoing will so fully reveal the gist of the embodiments of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute characteristics of the generic or specific aspects of the embodiments of the present invention. 
         [0128]    If not otherwise stated herein, it may be assumed that all components and/or processes described heretofore may, if appropriate, be considered to be interchangeable with similar components and/or processes disclosed elsewhere in the specification, unless an express indication is made to the contrary. 
         [0129]    If not otherwise stated herein, any and all patents, patent publications, articles and other printed publications discussed or mentioned herein are hereby incorporated by reference as if set forth in their entirety herein. 
         [0130]    It should be appreciated that the apparatus and method of the present invention may be configured and conducted as appropriate for any context at hand. The embodiments described above are to be considered in all respects only as illustrative and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.