Abstract:
An endovascular catheter combination configured to have multiple capabilities is disclosed. These capabilities include proximal and distal occlusion of a segment of a target blood vessel (such as the carotid artery) thus excluding the segment of the blood vessel from circulation for purposes such as surgical consideration. Another capability includes intravascular shunting of the blood through the excluded portion of the artery during a procedure such as an endarterectomy. Additionally, a microsensor provides a measurement of the rate/volume of blood flow through the distal end of the catheter. In one embodiment, a guidewire is provided with a filtration mesh as an anti-embolic mechanism both at the time of initial positioning of the catheter and after reversing the occlusion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and is a non-provisional of U.S. Patent Application Ser. No. 62/186,441 (filed Jun. 30, 2015) the entirety of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The subject matter disclosed herein relates to the general field of endovascular catheters used to treat vascular pathologies and specifically to an endovascular catheter with multiple capabilities which can serve as an adjunct to surgery on vascular structures. 
         [0003]    Stroke has plagued mankind since time immemorial. Its sudden and devastating effects were first recognized stroke as a pathologic entity by Hippocrates, often referred to as the Father of Medicine, over 2,400 years ago. Plato, Pope St. Leo, Charlemagne, Henry VIII, Woodrow Wilson, Vladimir Lenin, Sir Walter Scott, Richard Nixon and Margaret Thatcher are but a handful of historic figures who met their end as the result of stroke. Diligent postmortem studies demonstrated areas of the brain which had infarcted, presumably from interruption in circulation, although it took another seven decades to ultimately recognize that disease of the carotid arteries—which supply the majority of blood flow to the brain—was responsible for this malady in the majority of cases. Specifically, it is now known that atherosclerotic plaque along the walls of the internal carotid artery, usually just beyond the bifurcation of the common carotid artery, leads to narrowing of the lumen of the artery. This can result in stroke in two ways: first, the plaque can narrow the lumen to a dangerous point, and second, pieces of the plaque can break off, forming globules referred to as emboli. 
         [0004]    In the first scenario, the lumen can be narrowed to a critical point, reducing the blood flow to a point that it now longer meets the metabolic demands of the brain, causing a temporary reduction in brain function. A reflex increase in the muscle tone in the arteries can restore the blood flow after a few minutes, sometimes preventing further damage. Clinically, this sequence of events can initially result in a transient but fully reversible loss of neurologic function, a phenomenon known as a “Transient Ischemic Attack,” and more commonly known as a “TIA,” or “Mini-Stroke.” It is known that this phenomenon often heralds or is a precursor to a major stroke. If such a critical reduction of blood flow continues, an extensive blood clot can form within the carotid artery, resulting in extensive permanent loss of blood flow and massive damage to the brain, clinically resulting in a stroke. 
         [0005]    In the second scenario, the emboli break off and are then carried upstream where the arteries become smaller and smaller until a point is reached where the arteries become so small that these emboli cannot pass through. If the emboli are tiny, this may be insignificant. On the other hand, if the emboli are massive, they become lodged at a point where they stop blood flow to a major portion of the cerebral circulation, resulting in the loss of blood flow to large areas of the brain. It became apparent that if treatment could be instituted at a point when the patient first becomes symptomatic with TIA&#39;s perhaps the permanent damage from a stroke could be avoided. 
         [0006]    On that basis, in 1953 the great cardiovascular surgeon Michael De Bakey performed the first carotid endarterectomy (CEA). This is a surgical procedure in which the surgeon temporarily clamps off the common, internal and external carotid arteries and then incises the affected artery and removes the offending plaque prior to sewing the artery closed. By the 1980&#39;s, this had become one of the cornerstones in the treatment of stroke. However, a “double-edged sword” is that although CEA is performed to prevent future strokes in a patient, stroke is also the main complication CEA. Specifically, the rate of stroke as a complication of this surgery ranges from 2-7%. This is thought to be related to either the temporary loss of blood flow to the cerebral hemisphere, or emboli arising from manipulation of the artery. 
         [0007]    In an attempt to reduce the perioperative stroke rate, the 1970&#39;s witnessed the introduction of intraoperatively placing a tube or “intravascular shunt,” which carries blood from the common carotid artery at a point prior to where the artery is clamped off to the internal carotid artery at a point beyond where this artery is clamped off, and thus maintain flow to the brain. However, the use of intraoperative/intravascular shunting remains controversial. While the theoretical basis for the use of shunting is recognized by all, detractors of this technique point out that large, controlled studies have never proven, incontrovertibly, that shunting reduces the perioperative stroke rate. Moreover, a number of technical difficulties associated with the use of shunts have been cited by multiple authors. These shortcomings include the technical difficulties in positioning the shunt, the variability of time required for the placement, the inconstancy of the blood flow during surgery, and the need to clamp off the carotid to introduce and remove the shunt. With a persisting stroke rate being reported even with the use of intravascular shunts, the question of whether CEA was truly better than medical therapy alone needed to be addressed. 
         [0008]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0009]    The present invention is therefore provided to address the needs and goals disclosed above, as well as others. To that end, the invention discloses an endovascular catheter system which achieves these multiple objects in a unique, useful, novel and nonobvious fashion. 
         [0010]    One aspect of the invention is an endovascular catheter which is designed to be inserted through any artery or vein, such as the brachial or radial arteries and especially the femoral artery, using a Seldinger technique to study the carotid and is radiographically guided into the target carotid artery in such a way that the leading end has been guided past the target surgical area of plaque/stenosis. 
         [0011]    In particular, it is anticipated that placement of the catheter would be achieved by initial placement of a guidewire, said guidewire having important characteristics which would include a limited diameter such that it could be negotiated past the most severe areas of stenosis without creating an injury to the plaque; other important characteristics would include a soft, flexible nature which would again limit the possibility of creating an injury to the plaque stenosis. Furthermore, there would be, in the ideal embodiment, a deployable/expandable filtration net which would be deployed once the guidewire was in final position. Said net would be deployed prior to passage of the catheter, anticipating the (albeit small) possibility that positioning the catheter could result in injury to the plaque with consequent embolus formation and distal embolization; the net would be positioned to capture and ultimately retrieve any such embolus. This net would also, of course, capture any emboli created by the surgical manipulation. It has been postulated that there may be debris which serves as a source of emboli after removal of the plaque/stenosis. Therefore, as taught by Tsugita in U.S. Pat. No. 8,444,665, as well as Jang et al in U.S. Pat. No. 8,152,782 and others, the use of such a mesh may be beneficial in preventing the morbidity and mortality associated with postoperative embolic phenomena. In another embodiment, the catheter is designed so that it is disposed over a guidewire, said guidewire being provided with the mesh-like anti-embolic feature as well as being configured in deploy this mesh. 
         [0012]    This catheter is provided with a series of balloon occludes, as taught be Addis in U.S. Pat. No. 6,656,154 and others. The invention is provided with a first elastomeric occluder such as an inflatable/deflatable balloon which surrounds the outer surface of the catheter at its leading end which shall be known as the internal carotid balloon. When the catheter is in its final position and poised to be deployed, this balloon would be positioned within the internal carotid artery at a point beyond, or “upstream” from the target surgical area. Also provided is a second balloon, the common carotid balloon, which, in the desired position, would be located within the common carotid artery and hence prior to or “downstream” from the target surgical area. When both of these are inflated to the optimum pressure/volume, and in concert with external occlusion of the external carotid artery, the blood flow through the target area would be excluded hence providing the surgeon with a “bloodless,” operative field in order to remove the plaque/stenosis. Alternative embodiments of the arrangement of said balloons can be envisioned, with all such embodiments being included within the spirit and scope of the invention. 
         [0013]    In a different aspect of the invention, the catheter between these two balloons is provided with a lumen which is continuous with the lumen of the catheter prior to the common carotid balloon. In U.S. Pat. No. 4,581,017, Sahota teaches that a catheter with side apertures proximally and distally to an angioplasty balloon so that blood flow is maintained during angioplasty. This art does not, however, seek to create a “bloodless” operative field during the performance of Carotid Endarterectomy, distinguishing the present invention from this art. This section of the catheter in the present invention may be composed of an elastic/elastomer/expandable material which, upon exposure to continuous blood flow under pressure, can expand to accommodate a greater flow of blood. This expandable component continues through the internal carotid balloon. 
         [0014]    In another aspect of the invention, the catheter is provided with a series of apertures which are located along the shaft at a point prior/downstream from the common carotid balloon. These apertures encourage the blood flow, which has been interrupted by the inflation of the common carotid balloon, to be diverted into the lumen of the catheter, and to continue through the expandable portion and ultimately flow out of an aperture at the leading end of the catheter and into the lumen of the internal carotid artery beyond the internal balloon, thus creating a functional shunt which would provide continuous blood flow to the brain during the entire surgical procedure. The positioning and configurations of the apertures can be variable, and alternative embodiments can be conceived of and envisioned by those familiar with the art; all such embodiments would be incorporated within the spirit and scope of the invention. 
         [0015]    In yet another aspect of the invention, a flow monitor is provided to the leading end of the lumen which uses fiberoptic, Doppler, nanotechnology, or any other technology known or acceptable to the art to measure the flow and/or pressure that blood flowing out of the leading end of the catheter and into the internal carotid artery perfusing the brain. It is anticipated that in the ideal embodiment, such a monitor would telemetrically communicate with an external receiver/printer which would provide the surgeon with a continuous record of blood flow to the internal carotid artery during the surgical intervention. Alternate embodiments of this sensor are conceivable, and can be envisioned by those familiar with the art; all such embodiments are incorporated within the spirit and scope of this invention. 
         [0016]    This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
           [0018]      FIG. 1  is a diagrammatic representation of an embodiment of a catheter; 
           [0019]      FIG. 2A  depicts anterolateral aspects of a dissection of the structures of the neck demonstrating the right carotid artery system and associated structures; 
           [0020]      FIG. 2B  depicts a right arterial tree including the eight common branches of the external carotid artery, as well as the course of the extracranial internal carotid prior to entering the base of the skull; 
           [0021]      FIG. 3  is an anterior view of an isolated right carotid system, demonstrating typical plaque-stenosis; 
           [0022]      FIG. 4A  is a diagrammatic representation of the right carotid system showing the site of the arteriotomy and, in  FIG. 4B , the technique for removal of the plaque disease; 
           [0023]      FIG. 5A  is a diagrammatic representation of insertion of the catheter into the right carotid system using the Seldinger technique; 
           [0024]      FIG. 5B  is a diagrammatic representation of positioning of the catheter into the right carotid system using the Seldinger technique; 
           [0025]      FIG. 6A  to  FIG. 6H  depict passage of the leading end of the guidewire past the area of plaque-stenosis with the mechanism of deployment of the anti-embolic basket; 
           [0026]      FIG. 7  illustrates passage of catheter over guidewire prior to deployment of the internal carotid and common carotid balloons; 
           [0027]      FIG. 8  depicts deployment of the common carotid balloon with opening of the shunt; 
           [0028]      FIG. 9  illustrates removal of plaque-stenosis with sa hunt in place and retention of filtering mesh; 
           [0029]      FIG. 10  depicts collapse of the filtering mesh and removal of the catheter; 
           [0030]      FIG. 11  is an illustration of an alternative embodiment of a catheter showing reversal of the shunt useful in treatment of lesions such as abdominal aortic aneurysm; and 
           [0031]      FIG. 12  depicts a catheter useful during coiling treatment of intracranial aneurysms. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    Referring now to  FIG. 1  which is a general representation of a catheter  1 , the catheter  1  is provided with a leading end  2 , a central portion  3 , and a trailing end  4 . The catheter may be manufactured from a polymeric substance. The central portion  3  can be of varying lengths, and hence is shown with an interruption  5 . The leading end  2  is provided with a number of unique features, beginning with a filtering net-like basket  58 , which is actually the tip  57  of a guidewire used to place the catheter  1 . A netting of the basket  58  is designed to capture embolic detritus which may break off or result from the surgical procedure. The leading end  2  of the catheter  1  is also provided with a nanosensor  10  which is designed to determine and document the blood flow being delivered. An internal carotid balloon  7  and a common carotid balloon  11  are fabricated from an elastomeric substance. The deployment of the netting  63  is described more completely in  FIG. 6A  to  FIG. 6E  below. An interval portion  9  of the catheter  1  that lies between the two balloons represents the actual functional shunt, and in one embodiment is comprised of expandable or elastomeric substance such that once the shunt is established, a substantial blood flow is maintained through the shunt. In concert with this, at the leading end  2  of the lumen of the shunt is the nanosensor  10  for measuring blood flow, as well as the pressure which is driving that blood flow. On the other side of the interval portion  9  is the common carotid balloon  11 . The balloons  7  and  11  can be either spherical or somewhat elongated in configuration. In the embodiment of  FIG. 1  the internal carotid balloon  7  is spherical while the common carotid balloon  11  is slightly elongated. At the trailing end  4  are found syringes  13 ,  14  which are used to control the inflation of the balloons  7  and/or  11 . Syringe  13  is in continuity with lumen  18 , which is a separate small lumen within the body of the catheter  1 , and which through junction  19  is in continuity with the interior of the common carotid balloon  11 , thus enabling the syringe  13  to inflate or deflate the common carotid balloon  11  by the injection of media into the balloon. Analogously, the syringe  14  is in continuity with lumen  20  which, in turn, is in continuity through junction  21  with the internal carotid balloon  7 ; thus, the syringe  14  can inflate and deflate this balloon by either injecting or withdrawing media from the balloon. The media can be air, fluids, silicon-based media or any other substance known to or acceptable to the art. 
         [0033]    Aperture  22  is in continuity with a central lumen  15  through which contrast can be injected during insertion of the catheter  1 . Furthermore, the catheter  1  may be inserted over a guidewire which passes through the central lumen  15 . That portion of this central lumen  15  which is found in the internal portion  9  between the two balloons  7 ,  11  serves as the functional shunt  16  of the catheter  1 . The catheter  1  is provided with multiple apertures  17 , through which blood is carried with expansion of the common carotid balloon  11 . In order to assure antegrade flow of the blood through the apertures  17  and into the shunt  16 , a unidirectional valve  23  may be positioned in the central lumen  15  on the trailing side of the apertures  17 . 
         [0034]      FIG. 2A  depicts certain aspects of relevant normal and pathologic anatomy wherein the anterolateral aspect of the right side of the neck has been dissected by removal of the skin and superficial sheet of muscle known as the platysma. Furthermore, multiple muscles are demonstrated in a transparent motif, most particularly the prominent sternocleidomastoid muscle  105  which can be appreciated in most individuals as it extends from the mastoid process  106  cranially, bifurcating into two heads which attach to the manubrium of the sternum  107  medially and the clavicle  108  more laterally. The medial border of this muscle overlies the neurovascular bundle which includes the right internal jugular vein  91 , the right vagus nerve  92 , and the right common carotid artery  90 ; the relationships of these structures remain rather constant and are among of the most reliable anatomic landmarks. Also demonstrated in the transparent motif are the omohyoid muscle  122 , as well as the anterior  111 , medial  112  and posterior  113  scaleneus muscles, which lie superficial to the lateral aspect of the cervical vertebrae  110 , through which the vertebral arteries  95  pass, with the left and right vertebral arteries ultimately joining together to form the basilar artery, which irrigates critical structures in the brainstem and continues to bifurcate into the posterior cerebral arteries and contributes to the circle of Willis (Not demonstrated). Medial to the carotid/jugular neurovascular bundle lie the important midline structures including the trachea  123 , the thyroid gland  96  and the esophagus  97 . The brachiocephalic artery  98  arises from the aortic arch (not shown), bifurcates into the right subclavian artery  99  and the common carotid artery  90 . This artery ascends along the medial aspect of the sternocleidomastoid, and at approximately the C 3 - 4 , bifurcates into the internal carotid artery  100  and the external carotid artery  101 . The former offers no branches within the neck and is directed through the base of skull (not shown) to pursue its intracranial course; the latter has a total of eight extracranial branches, which are demonstrated in  FIG. 2B . This figure demonstrates the common carotid  90  arterial tree as it bifurcates into the internal carotid artery  100  and the external carotid artery  101 . This figure further illustrates the eight typical branches of the external carotid artery  101 , which include the Superior Thyroid  114 , Ascending Pharyngeal  115 , Lingual  116 , Facial  117 , Occipital  118 , Posterior Auricular  119 , Maxillary  120 , and Superficial Temporal  121 . It is this extensive arterial tree which provides the well-known richness of vascularity to the scalp. 
         [0035]    In  FIG. 3 , a diagrammatic representation of an isolated right carotid system demonstrates the bifurcation of the common carotid artery  90  into the internal carotid artery  100  and the external carotid artery  101 . The significant plaque-stenosis  102  is demonstrated at the takeoff of the internal carotid artery  100 , with plaque disease occasionally extending to the bifurcation  103  itself (solid area) as well as the origin of the external carotid artery  101  (cross-hatched). The illustration herein demonstrates a narrowing of approximately 70%, which is widely considered to be the threshold for surgical intervention, particularly in symptomatic patients. 
         [0036]    The current surgical technique used to treat such carotid disease is illustrated in  FIG. 4A  and  FIG. 4B . In  FIG. 4A , the site of the arteriotomy  104  is shown, as well as the sites where the common carotid artery  90 , internal carotid artery  100 , and external carotid artery  101  are occluded, typically by tying off with vascular tapes ( 42 ,  40  and  41  respectively), as shown here. In  FIG. 4B , the arteriotomy  104  is opened, and the plaque-stenosis  102  is being removed with a dissector  130  using the technique of a classic endarterectomy. It can be seen that the internal carotid artery  100  is tied off with a vascular tape  40  as is the external carotid artery  101  with vascular tape  41  and the common  90 , tied with vascular tape  42 . 
         [0037]    As shown in  FIG. 5A , the catheter  1  herein disclosed may be inserted using a Seldinger technique. This has been established as a safe and effective way to place a diagnostic/therapeutic catheter into the arterial tree, including the carotid arteries. In  FIG. 5A , this technique is diagrammatically illustrated, showing an example of an entry point  45  in the right groin (either groin can be used). A sheath  50  is placed after initial puncture of the (typically right) femoral artery  51 . As shown in  FIG. 5B , a guidewire  52  is then advanced in a retrograde fashion (against the blood flow) into the aorta  55 . After the tip  57  of the guidewire  52  is passed through the arch  53  of the aorta, it is advanced in anterograde (same direction as the blood flow) into either the brachiocephalic artery  54  and then into the right common carotid artery  90  as in the illustrated instance, or the left common carotid  56 , depending on the ultimate target. After being advanced into the right common carotid artery  90 , it is ultimately advanced into the right internal carotid artery  100 . 
         [0038]      FIG. 6A  shows the carotid artery system within the neck as the guidewire  52  is advanced into the desired position. As illustrated previously in  FIG. 3 , the origin of the internal carotid artery  100  just distal to the bifurcation of the common carotid artery  90  is the typical locus for the plaque-stenosis  102 , again recalling that the plaque can extend to the level of the bifurcation  103 , or even the origin of the external carotid artery  101 , with plaque shown as the cross-hatched area. Isolating this section of the arterial system is necessary to achieve complete treatment of the disease. The external carotid  101  is again tied off with vascular tape  41  in the standard fashion, although an alternative embodiment utilizing a third lumen for positioning within this artery is conceivable. The leading end of the guidewire  52  is gently disposed through the area of the disease until the leading end  2 , which has been provided with the deployable basket  58  to capture embolic detritus is positioned substantially beyond the area of the disease. 
         [0039]    In  FIG. 6B ,  FIG. 6C ,  FIG. 6D  and  FIG. 6E , the mechanism for deployment of the anti-embolic basket  58  is more completely illustrated. In  FIG. 6B , an enlarged, lateral image of the isolated tip  57  of the guidewire  52  shows that the unique composition of the guidewire  52 , in combination with the design of the deployable basket  58 , allow for a unique, useful novel and nonobvious method to achieve deployment of the basket  58 . The guidewire  52  is comprised of a central, internal wire  59  which is invested within an external tubular wire  60 . In this view, the basket  58  is not yet deployed, being maintained in its primary position by a series of tethers  62  which extend from the leading end of the external tubular wire  60  to the periphery  61  of the deployable basket  58 . The internal tubular wire  59  and external tubular wire  60  wires are configured such that they can be slidably repositioned with respect to one another. The deployable basket  58  is comprised of a netting  63  with fine apertures, which is attached centrally to the internal wire  59  (see, for example,  FIG. 6C ) of the guidewire  52 . The netting  63  can be fabricated from either the same types of metal the wire is composed of (copper, nickel, aluminum) or it can be fabricated from polyester. It is important, however, that regardless of the material from which it is fabricated, that there is an element/scaffolding included which maintains a positional “memory,” such that when the netting  63  is allowed to position itself by relaxation of the tethers  62 , it returns to a position of function, which would be generally concave facing the flow of blood. Hence, emboli being carried along in the blood flow would be trapped by the netting  63 . 
         [0040]      FIG. 6C  is an enlarged, elevational view of the trailing end of the guidewire  52 . The unique arrangement and relationship of the trailing end  25  of the internal wire  59  and the trailing end  26  of the external wire  60  ultimately provides for the deployment of the anti-embolic basket  58  (not shown in this picture). In this relationship, the trailing end  25  of the internal wire  59  protrudes beyond the trailing end  26  of the external wire  60 . A platform  27  is provided. In one embodiment, the platform  27  is monolithic with the trailing end  25  of the internal wire  59  and has an extension  28  that is directed towards the external wire  60 , being positioned adjacent and closely related to the external diameter of the external wire  60 . A platform  29  is also seen arising from the external diameter of the external wire  60 , the platform  29  being provided with an aperture  30 . The platform  29  is positioned such that the extension  28  of the platform  27  of the internal wire  59  is disposed through the aperture  30 . A fastening mechanism  31  is provided to the platform  29  arising from the external wire  60 . The fastening mechanism  31  regulates the position of the extension  28 , which continues beyond the aperture  30  of the platform  29  arising from the external wire  60 . A leading end  32  of the extension  28  is enlarged, acting as a stop during deployment of the basket  58 . These actions will be elucidated below. 
         [0041]      FIG. 6D  further depicts the structures of the trailing end of the guidewire  52  in this lateral view. Again it can be seen that the trailing end  25  of the internal wire  59  extends beyond the trailing end  26  of the external wire  60 . The platform  27  arising from the internal wire  59  is readily appreciated in this perspective, as is the extension  28  which is directed towards the central portion of the guidewire  52 , with the extension  28  being disposed through the aperture  30  (projected on end) of the platform  29  arising from an external surface of the external wire  60 . The position of the extension  28  is controlled by a fastening mechanism  31  inserted into the platform  29  arising from the external wire  60 . The enlargement of the leading end  32  of extension  28  can also be seen in this depiction. Furthermore, it can be seen that if the external wire  60  is advanced towards the leading end of the internal wire  59 , the platform  29  will be advanced along extension  28  until it reaches the enlargement which acts as a stop. The distance between the leading side of the platform  29  and the beginning of the enlargement correlates with the distance required to advance the leading end of the external wire  60  sufficiently to completely relax the tethers  62  (not shown in this image), thus allowing the basket  58  (also not shown) to deploy. 
         [0042]      FIG. 6E  and  FIG. 6F  demonstrate the interplay of the trailing ends  25 ,  26  of the internal and external wires  59 ,  60 , result in deployment of the basket  58 , resulting in the anti-embolic action.  FIG. 6E  demonstrates the tip  57  of the guidewire  52  within the internal carotid artery  100 . The leading end of the external wire  60  can be seen advancing towards the leading end of the internal wire  59 ; the advancing external wire  60  is depicted by the lines  60   a,  and moves in the direction indicated by the arrow. For illustrative purposes, the ghosted image of the external wire  60  which is translated is depicted as slightly larger than the depiction of the non-deployed external wire  60 . The non-deployed basket  58  is seen at the leading end of the internal wire  59 . In  FIG. 6F  the simultaneous actions at the trailing ends  25 ,  26  of the internal wire  59  and the external wire  60  contribute to the actions occurring at the tip  57  of the guidewire  52 . Specifically, in this lateral view, the trailing end  26  of the external wire  60  can be translated with release of the fastening mechanism  31  in platform  29 , which secures the extension  28 . With release of the fastening mechanism  31 , the external wire  60  can be translated along the internal wire  59  towards the leading end as shown in  FIG. 6E . In  FIG. 6F  this transposition is again in the direction indicated by the arrow, with the transposition of the external wire limited by the interface of the platform  29  with the enlarged leading end  32  of extension  28 . The transposition can be further understood as shown by the dotted lines depicting the trailing end  26  of the external wire  60  and the platform  29 . Dotted lines from numbers to aspects of the image further indicate the original positions of the structures prior to the translation. At the leading end, as shown in  FIG. 6E , external wire  60  is advanced toward the leading end of the internal wire  59 , as indicated by the arrow. As the transposed external wire  60   a  approaches leading end of the internal wire  59 , the tethers  62  are relaxed. This allows the memory component of the netting  63  to return to its primary configuration, and in that way the basket  58   a  can be deployed and expand into its fully deployed configuration. It is anticipated that the basket could be, and in the preferred embodiment would be coated with an anticoagulant to further help reduce/ break up and emboli comprised of blood clot. 
         [0043]      FIG. 6G  shows the final position of the fully deployed basket  58  at the tip  57  of the guidewire  52  within the internal carotid artery  100 . The external wire  60  has been advanced towards the leading end of the internal wire  59  until the tethers  62  are radially dispersed allowing the basket  58  to be fully expanded, with the netting  63  being completely brought against the internal surface of the artery. The internal wire  59  continues to the central portion of the basket  58 .  FIG. 6H  shows the final position of the trailing end  25  of the internal wire  59  with respect to the final position of the trailing end  26  of the external wire  60 . Platform  27  gives rise to the extension  28  which is disposed through aperture  30  (not seen) in platform  29 . This configuration has allowed the external wire  60  to advance toward the leading end of the internal wire  59 , with the enlargement  32  serving to arrest the advance of the external wire. It is noted that in this position, the fastening mechanism  31  is in a “locked,” position so that the basket  58  on the leading end is not prematurely or inadvertently reconfigured or returned to its primary position. 
         [0044]    With reference to  FIG. 7 , after final positioning of the tip  57  with expansion of the basket  58 , the catheter  1  is disposed over the guidewire  52 . The tip  57  is seen extending beyond the leading end  2  of the catheter  1 .  FIG. 7  demonstrates the leading end  2  of the catheter  1  having been positioned. The common carotid balloon  11  and internal carotid balloon  7  have not yet been expanded within their target arteries, and are seen on the sides of the catheter  1 . The central shunt portion of the catheter  1  is seen extending beyond the plaque-stenosis  102 . With the occlusion of the arteries by the balloons  7 ,  11  a “bloodless” field is created which allows the surgical intervention to proceed, as outlined below. As will be demonstrated below, with the inflation of the common carotid balloon  11 , the apertures  17  will become active, shunting blood from the common carotid artery  90  through internal portion  9  and conducting blood to the internal carotid artery  100 . As previously discussed, the unidirectional valve (not demonstrated in this image) prevents blood from backflowing into the catheter  1 . A nanosensor  10  is provided to the leading end  2  of the catheter  1 . Using microtechnology and/or nanotechnology, this sensor provides a measurement of blood flow as well as the pressure under which the blood is flowing. The external carotid artery  101  is tied off with vascular tape  41  prior to the origin of the first branch, the superior thyroid artery  114 . 
         [0045]    In  FIG. 8 , the expansion of the common carotid balloon  11  results in the blood being preferentially diverted into the apertures  17  and subsequently through the internal portion  9  (as indicated by the arrows) past the area of the plaque-stenosis  102 , ultimately maintaining continuous cerebral flow upon exiting through the aperture  24  at the leading end  2  of the catheter  1 . In the embodiment of  FIG. 8 , a single aperture  24  is shown. In other embodiments, more than one aperture is present. This flow is measured by the nanosensor  10  and transmitted to an outside recorder (not shown) documenting continuous blood flow during the entire procedure. The basket  58  remains intact to capture any embolic debris that could occur as the result of the catheter&#39;s presence. To assure anterograde flow and prevent backflow of blood through the trailing end of the catheter (not shown), a unidirectional valve  23  has been provided to the central lumen  15  of the catheter  1 . The internal carotid balloon  7  has also been deployed. The external carotid artery  101  remains occluded by vascular tape  41 , prior to the takeoff of the first branch, the superior thyroidal artery  114 . 
         [0046]      FIG. 9  shows the actual endarterectomy being performed through an arteriotomy (incision of the artery)  104 , with the dissector  130  removing the plaque-stenosis  102  from the artery. The shunt portion of the catheter is seen in the center of the operative field; however, surgeons can easily work around this device. Blood flow has never been interrupted, and has been documented by the sensor  10 . The internal carotid balloon  7  and common carotid balloon  11  are inflated and maintain a bloodless field, along with the vascular tape  41 . 
         [0047]      FIG. 10  is an image of the tip  57  of the guidewire  52  within the internal carotid artery  100 , illustrating that upon completion of the procedure, the basket  58  is collapsed by repositioning the external wire  60  towards the trailing end of the internal wire  59 , as indicated by the direction of the open arrowhead. This is further illustrated by the dotted lines, representing the deployed position of the external wire  60   a.  The solid lines  60  show the final position of the external wire. This repositioning draws the tethers  62  centrally, which uniformly pulls on the circumference of the netting  63  causing it to collapse around the leading end of the internal wire  59 . This repositioning, in turn, serves as an actuator causing the basket  58  to collapse encircling the leading end of the internal wire  59 , as demonstrated by the curved solid arrows. The final position of the basket  58  prior to removal is indicated by the ghosted image in dotted lines  58   a.  Any emboli  135  which may have been trapped within the basket  58  are now secured into final position for retrieval upon removal of the guidewire  52  and catheter  1  from the insertion site in the groin at the end of the case (not shown). 
         [0048]      FIG. 11  shows an alternative embodiment of a catheter  140  which is inserted over a guidewire  141 . The positioning of the catheter  140  is such that the flow through the shunt is not directed towards the leading end, as in the embodiment described above. Instead, in this embodiment, apertures  142  are positioned beyond the occluding balloon which is found on the leading portion  143  of the catheter  140 . The blood enters the apertures  142  (as indicated by the arrows) and flows through the central channel  147  exiting from the trailing portion  146  of the catheter  140 , beyond the trailing balloon  144 . As the blood flows out of the trailing portion  146  of the central portion of the catheter  140 , a flow sensor  151  measures the blood flow and/or pressure under which the flow proceeds. The balloons would again be inflated with the use of syringes  148 ,  149  at the trailing end  150  of the catheter. The syringes  148 ,  149  are connected to minor lumina within the walls of the catheter (not shown in this image), which are ultimately connected to the balloons, and which transfer media to the balloons in order to inflate them. As previously stated, the media could be air, water, silicon-based media, or any other substance known or acceptable to the art. This embodiment could be useful in pathologies such as ruptured abdominal aortic aneurysms  145 , thus preserving blood flow through the catheter to points beyond the distal aorta. 
         [0049]      FIG. 12  is an iteration which reflects the potential for use in the endovascular treatment of intracranial aneurysms. The treatment of such aneurysms frequently involves placement of a wire coil  152  into the aneurysm  154 . In this image of this iteration, the catheter  155  is within a cerebral artery, wherein a separate lumen  153  allows for the delivery of such a coil into the aneurysm  154 . The balloons in this catheter  155  are designed to have a malleable configuration so that balloons  156  and  157  are able to conform to the local anatomy, in particular the relationship with local vessels such as in this example, whereby the trailing balloon  157  occludes another local vessel which is feeding the distal cerebral structures. The system herein disclosed allows for coiling the aneurysm while excluding the aneurysm from circulation and maintaining continuous flow, as measured by the flow sensor  158 . A major complication of this type of aneurysm treatment is rupture of the aneurysm with consequent severe bleeding. Use of the catheter controls such bleeding until definitive surgical intervention could be achieved. 
         [0050]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.