the invention includes various solutions to the removal of atherosclerotic plaque from arteries . this invention includes methods and devices for performing percutaneous endarterectomy ( i . e . removal of atherosclerotic plaques from arteries via a e . g . a catheter ). the devices and methods may release plaque at its edge and peel away the plaque naturally , preferably , for example , along the subintimal space . all may be preferably based on the same principle of utilizing the natural dissection plane , which in the subintimal space , exists between the plaque and the media of the artery , for removing the plaque with a percutaneous tool . as known to those skilled in the art , the subintimal space is a potential space where a false lumen could form if blood flow were to enter it through an intimal tear and cause an arterial dissection . it is the same space used for passing the guidewire and creating an artificial extraluminal route in subintimal angioplasty procedures ( the bolia technique ), and where the plaque is usually separated from the arterial wall in open endarterectomy operations . a recent article reports a case in which an occluded artery was endarterectomised two months after a subintimal angioplasty was performed on it , and histological cuts demonstrated that “ the subintimal track had been formed between the internal elastic lamina and the atherosclerotic plaque at most levels .” scholtes et al ., “ subintimal angioplasty track of the superficial femoral artery : a histological analysis ”, circ cardiovasc interv . ; 2012 ; 5 : e6 - e . 8 . it is therefore thought that subintimal angioplasty is not a random extraluminal revascularization procedure but creates subintimal passage in the form of a dissection between the atherosclerotic plaque and the media of the artery .” scholtes et al . in this invention , the plane between the media and intima is utilized because it may be the pathway of least resistance around the plaque . as such , the guidewire in subintimal angioplasty procedures usually finds its way into the subintimal space quite naturally . the current invention describes additional ways in which to enter this space . fig1 a - b show two different common structures of the edge of an atherosclerotic plaque in an artery . with reference to fig1 a the artery comprises normal media 10 and normal intima 11 . the atherosclerotic plaque 12 in the artery is shown in both fig1 a and fig1 b . fig1 b also illustrates the atherosclerotic ( thickened ) intima 13 . two general directions are described , which differ in the aspect from which the plaque is approached : its edge or the medial aspect . “ plaque &# 39 ; s edge ,” as used herein refers to the border of the occluding lesion , whether proximal or distal . in some cases , as shown in fig1 a , the lesion may have a distinct , abrupt border between a normal or essentially normal area and a stenotic area , wherein an actual “ step ” in thickness of the intima is present . in other cases , this border may be less distinct , with a gradual transition or tapering between the stenotic and patent areas of the artery ( fig1 b ). in such cases , the “ edge ” would be a location initially chosen by the physician , from which the stenosis is deemed of no clinical significance . “ medial aspect ” refers to an approach to the plaque beginning with passage of a device in the subintimal space throughout the length of the lesion . all the described procedures and tools are preferably used after deployment of an embolic protection device in the artery . alternatively , by way of example , the treated area may be isolated by inflating balloons at one or both of its ends . the tools and methods described herein may be used with slight modifications either in an antegrade or in a retrograde fashion . antegrade use refers to advancement around the plaque while the device is being pushed forward . this has the advantage of not necessitating traversing of the lesion before initiation of treatment ; hence , it is appropriate for the treatment of cto lesions ( chronic total occlusions ). the disadvantage is that pushing the device forward may be more difficult technically than pulling it . retrograde use refers to advancement around the plaque while the device is being pulled backward . this requires that the device be passed through the lesion prior to initiation of treatment . only then can it be deployed and pulled back . the main disadvantage is that the lumen through some lesions may be so stenotic as to prevent passage of the catheter , in which case this approach cannot be used . on the other hand , this approach may be more suitable for lesions at bifurcations . after placing the treatment catheter at the vicinity of the lesion , demonstrating it , optionally placing any of the many available embolization protection devices , and anchoring the treatment catheter , treatment may follow these stages : 1 . access into the subintimal space . this entails passage of an instrument into the subintimal space (“ sis ”), and in some cases initial separation of the plaque , a process herein referred to as “ edging ,” which may be performed using an “ edger ” tool . such separation is intended to enable further separation of the plaque from the arterial wall , herein referred to as “ dissection .” 2 . dissection of the plaque . this entails separation of the plaque from the arterial wall around its circumference and along its whole length . dissection may be performed using a specialized “ dissector ” tool , or in some embodiments with the edger tool . 3 . distal cutting . after the plaque was separated all around , the intima connecting the distal part of the plaque to the arterial wall may be cut . 4 . closure . a device enclosing the plaque is generally closed so as to contain the plaque and its fragments . 5 . removal . the device with the plaque in it is removed from the artery . 6 . medial surface treatment . optionally , treatment may be applied that enhances arterial healing and attenuates thrombogenicity and platelet adhesion to the exposed medial surface . such treatment may consist of re - endothelialization therapy by e . g . instillation of endothelial progenitor cells , stem cells , or other cells or substances . typically , such treatment will be applied using a specially designed balloon catheter system which keeps the cells / substance in contact with the arterial wall while at the same time allowing continuous blood flow through the treated area . the tools and methods described herein are aimed at removal of the plaque as a whole , preferably in one piece . for example , the exemplary devices and methods described herein provide for release of the plaque , preferably at its edge , and peeling of the plaque . a different approach is to use a grinder / macerator tool , which can also be used along with certain aspects and embodiments of the current invention . however , such a tool adds complexity , cost , and danger to the system , and in addition , grinding the plaque releases various deleterious thrombogenic and inflammatory substances into the blood stream , hence the preference for removal of the plaque without disintegrating it . most preferred embodiments of the invention are based on the approach of attacking the plaque from its edge . in particular , the devices and methods of the invention provide for release of the plaque , such as through scraping and peeling of the plaque . preferably , this is done without making a cut into the intima and / or media . without radial cutting , grinding or abrading the plaque as the primary removal technique , the plaque may be scraped or edged away from the vessel wall to be peeled away along the natural dissection plane . in one embodiment , a device , utilizing , for example , fingers or projections , approaches the plaque from inside the vessel to contact and / or engage the plaque with a scraping action , for example , to find the way into the subintimal space . with the scraping action , the plaque / intima layer separates because the plaque / intima is naturally peeled away . the methods and devices of the invention do not rely e . g . on radial cutting , grinding , or abrasion and as such are much more gentle . in a preferred embodiment , an edger tool is provided including a tubular member from which end extend several elongated radially expandable “ fingers .” an example of such tool based on an umbrella like mechanism is shown in fig2 a - 2e . fig2 a is a three - dimensional depiction of edger 20 which is passed through catheter 30 . it includes of shaft 24 from which extend fingers 21 . rod 25 extends through shaft 24 and is connected to each finger 21 by spoke 26 . at centerlines 22 of fingers 21 near their edge may be additionally installed radiopaque marker 23 . a longitudinal section of edger 20 in its open position is shown in fig2 b and in its closed position in 2 c . fingers 21 may be formed of an elastic material and pre - shaped in the open position , such that when pushed out of guiding catheter 30 and in the absence of pulling resistance by rod 25 , the edger will open . in such case , release of rod 25 controls the degree of finger 21 radial expansion and open diameter . alternatively , finger 21 radial expansion may depend on pushing rod 25 forward . in any case , following radial expansion , fingers 21 assume a position essentially parallel to that of shaft 24 longitudinal axis ( fig2 b ). a slightly different example of edger tool is shown in fig2 d - 2f . this tool is similar to edger 20 but has additional spokes intended to maintain the fingers &# 39 ; parallel position . more particularly , fig2 d is a 3d depiction of edger 40 which is passed through catheter 30 . it includes shaft 44 from which extend fingers 41 . rod 45 extends through shaft 44 and is connected to each finger 41 by inner spoke 46 and a more distal outer spoke 47 . inner spoke 46 and outer spoke 47 are of the same length , and the distances between their connection points on finger 41 and on rod 45 are also equal , such that they form a parallelogram . at centerlines 42 of fingers 41 near their edge may be additionally installed radiopaque marker 43 . a longitudinal section of edger 40 in its open position is shown in fig2 e and in its closed position in 2 f . fingers 41 may be formed of an elastic material and pre - shaped in the open position , such that when pushed out of guiding catheter 30 and in the absence of pulling resistance by rod 45 , the edger will open . in such case , release of rod 45 controls the degree of finger 41 radial expansion and open diameter . alternatively , finger 41 radial expansion may depend on pushing rod 45 forward . in any case , following radial expansion , fingers 41 assume a position essentially parallel to that of shaft 44 longitudinal axis ( fig2 e ), which is maintained at any opening diameter due to the parallelogram design . in one embodiment , the fingers 41 arc of the same length . the fingers are designed so that radial force applied by the fingers decrease going from the proximal to the distal end of the tip ( relative to the plaque ). thus , in one embodiment , the fingers deliver more force on the proximal end of the finger and less force on the distal end . in one embodiment , the tips of fingers are parallel to the shaft so that they do not cut the artery and so they are substantially in the direction of the dissection plane . the fingers are also so configured that they are more rigid towards the distal end and more flexible to the distal end . furthermore , the edges of the fingers may be blunt or rounded . thus , in one embodiment , the radius at the end of the fingers is not sharp , rather it is blunt and sufficient to find the edge of the plaque without cutting the intima . the fingers , in this configuration , may be used to remove the plaque in a forward motion . in one embodiment , the longitudinal sections of the fingers are parallel . it is thought that less force on the distal end results in a device that provides for a more gentle removal of the plaque and the ability to find the natural separation of the plaque . the embodiments shown and described herein are exemplary . for example , the force differences can be achieved in a variety of ways including structurally ( via e . g . use of structural features such as struts and guidewires or a changing cross - section ) or functionally ( via e . g . use of a different materials ). fingers 41 as shown in fig2 a have a thin configuration that may be flat or curved as desired in accordance with the principles of the invention . although other configurations may be used in accordance with the principles of the invention , for example , the lateral and transverse cross - sections of finger 41 may vary , and , further may vary , for example , as discussed in other embodiments described herein . finger cross - sections also are shown in fig1 g - k . in another embodiment , the fingers may be sharp and the fingers are configured to find the edge of the plaque without radially cutting the intima . in another embodiment , due to the lateral positioning of the edger relative to the plaque , the fingers , may be relatively blunt , sharp or otherwise in accordance with the principles of the invention to accomplish the scraping and / or edging of the plaque so it may be removed along its natural dissection line . the fingers of the edger tools in accordance with the principles of the invention may be caused to probe along the arterial wall to find the edge and / or natural line / plane of dissection of the plaque . in one embodiment , the fingers press gently against the arterial wall and gently scrape the plaque to find the edge and / or natural separation . fig2 a - 3e show the stages of edger 40 use . more particularly fig3 a shows longitudinal section of artery having inner diameter 15 with media 10 and plaque 12 at a distance 14 from tip of catheter 30 , which is anchored by balloon 31 . fig3 b shows edger 40 in its closed position passed through catheter 30 . fig3 c further shows edger 40 in its open position . fig3 d shows the above with edger 40 being advanced towards plaque 12 . fig3 e further shows fingers 41 separating between media 10 and plaque 12 . the distal portions of the fingers may also be substantially parallel to the central axis of the device e . g . pushing rod in use , guiding catheter 30 is brought to the vicinity of the target lesion 12 which is then demonstrated angiographically . if possible , an embolization protection device is deployed . the guiding catheter has a balloon 31 around its tip , which is inflated to anchor the catheter with its tip at a distance 14 from the plaque &# 39 ; s edge , typically approximately 0 . 5 - 1 cm in a large ( approximately 6 - 8 mm ) artery , but possibly as short as approximately 1 - 5 mm in a small or medium ( approximately 2 - 6 mm ) artery ( fig3 a ). arterial diameter 15 at the plaque edge is measured angiographically and an edger tool is chosen having an open diameter at least approximately 10 % larger than arterial diameter 15 . edger 40 is deployed through guiding catheter 30 ( fig3 b ) and expanded such that its fingers are slightly pressed against the arterial wall ( fig3 c ). this can be verified angiographically . edger 40 is then rotated along its longitudinal axis and advanced towards lesion 12 ( fig3 d ). this separates the edge of plaque 12 from media 10 , such that fingers 41 are in the sis ( fig3 e ). the normal medial layer of the arterial wall has much higher axial flexibility ( ultimate stretch greater than about 1 . 5 ) compared with the normal intimal layer , and these differences are exaggerated when comparing normal media to atherosclerotic intima in which both axial and circumferential flexibility are reduced ( ultimate axial stretch of about 1 . 1 - 1 . 2 ). calcified plaque elements are essentially rigid with an ultimate stretch of approximately 1 . 02 ( see holzapfel ag et al ., “ anisotropic mechanical properties of tissue components in human atherosclerotic plaques ” journal of biomechanical engineering , 2004 , 126 ; 657 - 665 ). these differences in mechanical properties aid in the process of separation between the layers by the edger tool , which applies both circumferential and axial forces on all layers . the different response of each layer to these forces creates shear forces between the layers , which lead to their separation . optionally , verification of proper “ edging ” can be done angiographically , as seen in fig4 a - 4b . fig4 a shows a schematic of an angiogram in case of successful edging . edger 20 is shown through catheter 30 with radiopaque marker at the tip of finger 21 . filling defect 33 is seen between contrast material 32 and finger 21 . fig4 b shows a schematic of an angiogram in case of unsuccessful edging . edger 20 is shown through catheter 30 with radiopaque marker at the tip of finger 21 . no filling defect 33 is seen between contrast material 32 and finger 21 . as shown in fig4 a , the correctly positioned fingers are demonstrated external to the edge of the plaque , which is seen as a filling defect , whereas in fig4 b , the fingers are internal to the plaque edge , which means the edging was not successful . at this stage of the procedure , a dissector tool is introduced over the edger tool through the guiding catheter . an example of a dissector made of looped metal ( such as nitinol ) wires is shown in fig5 a - 5c . more particularly , fig5 a shows dissector 50 made of wire loops 51 , which may or may not be connected to each other by connector 52 . the distal most part of each loop is at its centerline 53 . fig5 b shows a similar dissector wherein each loop 51 is braided with the adjacent loop 51 . fig5 c shows a possible more intricate pattern of braiding in which several loops are interlaced with each other . the number of loops 51 in dissector 50 may vary between 2 - 8 but is typically 3 - 5 . loops may be completely separate as in 5 a , or every two adjacent wires may be connected to each other by a connector 52 . the braiding may be a simple one , involving only each two adjacent wires as in fig5 b , or more intricate including several loops as shown in fig5 c . alternatively , such dissector may be formed of laser cut metal sheets or tube . fig6 a - 6b show use of dissector 50 . more particularly , fig6 a is a three dimensional depiction of dissector 50 , which is seen coming out of catheter 30 , with its loop centerlines 53 over edger 20 finger centerlines 22 . fig6 b shows a longitudinal section of an artery with plaque 12 , and catheter 30 anchored by balloon 31 . dissector 50 is seen coming out of catheter 30 and being inserted into the sis over edger fingers 21 . in use , as the dissector is pushed forward out of the guiding catheter ( fig6 a ), the user can rotate it to bring the centers of the loops 53 in line with the edger finger centerlines 21 . thus , the edger serves as a guide for the dissector into the sis ( fig6 b ). once the dissector loops pass the edger fingers , the edger can be retracted and removed . optionally , the interior of guiding catheter 30 may be shaped with grooves that help align the edger and dissector tools . the dissector is then advanced in the sis under angiographic monitoring until it reaches the end of the lesion . advancement of the dissector is achieved by a combination of forward push and rotation . the dissector loops will tend to expand as it is pushed forward , pressing against the flexible media and away from the more rigid plaque , which aids in the separation process . once dissector 50 passes lesion 12 , dissector loop ends 53 might tear through intima 11 and enter the lumen without any action on behalf of the user . such automatic re - entry may be enhanced by pre - shaping the dissector &# 39 ; s nitinol loops with a curve towards the center of the lumen . however , this type of unintended re - entry carries a high chance of producing an intimal flap , which in turn might cause an arterial dissection , a dangerous complication of endarterectomy , which can lead to clogging of the artery , thrombosis , aneurysm or perforation . if an intimal flap is observed or suspected , it can be treated by placement of a stent over the transition area between the endarterctomized artery and untreated intima . in the current embodiment , in order to prevent the above , the dissector loops are shaped with an outward curve to reduce their tendency for re - entry . an intima cutting tool is provided as part of the dissector to enable smooth re - entry . such tool 60 is shown in fig7 a - 7e . more particularly , fig7 a & amp ; 7b are three - dimensional depictions of intimal cutting tool 60 including blade 61 and guard 62 , slideably held together by holder 63 . fig7 a shows the closed position of cutting tool 60 whereas fig7 b shows the open position of cutting tool 60 . fig7 c is an end view and fig7 d a side view of cutting tool 60 . fig7 e shows typical assembly of cutting tool 60 over centerline 53 of loop 51 of dissector 50 . fig8 shows use of cutting tool 60 in a longitudinal section of an artery with media 10 , plaque 12 separated by dissector 50 , with cutting tool 60 over it , cutting through intima 11 . a close - up view of the re - entry area is shown , with blade 61 sliding over guard 62 and loop centerline 53 of dissector 50 , bending towards the lumen , and cutting through intima 11 , creating an incision in intima 11 having an angle 64 with longitudinal axis of artery . intimal cutting tool 60 may be include two parallel metal strips , a blade 61 , and a guard 62 , held together by holder 63 . blade 61 has a sharp tip and side , whereas guard 62 has a rounded tip and blunt sides . blade 61 is also pre - shaped with an arch , such that when slid forward over the guard , its sharp area is exposed and it arches to the direction of the guard . the cutting tool is typically attached to one of the dissector loop centerlines 53 ( fig7 e ). in use , when the dissector passes the lesion , the blade 61 is deployed ( fig8 ), penetrating through the intima in a sharp angle 64 . the whole dissector is then rotated along its longitudinal axis such that the intima is cut all around the lumen , without leaving an intimal flap . the blade is retracted . the entire intimal core is now completely separated from the arterial wall . the dissector is pulled backwards . this causes the loops to lengthen and the dissector &# 39 ; s diameter to decrease , compressing the intimal core , and holding on to it . this enables removal of the complete core with the dissector . the above was a general description of a preferred embodiment . specific modifications of each stage and tool may be employed to improve performance of the invention . following are some such modifications . the anchoring balloon of the guiding catheter may be formed as several separate balloons ( fig9 a ), or having several conduits through it ( fig9 b ), to allow continuous blood flow across the treatment area during the procedure . this may be essential when the procedure is performed in areas that cannot tolerate cessation of blood flow , for example in case of treating a carotid artery when contralateral circulation is insufficient . of course , in such a case , a distal protection device would be crucial . fig9 a shows catheter 30 surrounded by split balloons 34 , and fig9 b shows a balloon having conduits 35 through it . in a different embodiment of the edger tool , referring generally to fig1 aa , 10 bb and 10 cc , the tool may include an elongated member from which end at least one “ finger ” ( fig1 aa & amp ; 10 bb ) but preferably three “ fingers ” ( fig1 cc ) or more “ fingers ” project retrogradely . radial expansion of these fingers may be achieved by their being made of a shape memory alloy such as nitinol , or by other means or ways such as an inflatable balloon . limitation of the radial expansion of the fingers for example by a slideable external sheath enables control over the degree of contact with the arterial wall and force applied to it . in one embodiment , the edger tool complete with the sheath is deployed through the guiding catheter which is anchored by the balloon . the sheath may function to only open and close the tool . the fingers are designed so that radial force applied by the fingers decrease going from the proximal to the distal end ( relative to the plaque ). in one embodiment , the fingers are parallel so that they do not cut the artery and so the fingers extend substantially in the direction of the dissection plane . the fingers are also so configured that they arc more rigid towards the distal end and more flexible to the distal end . in another embodiment , the edges of the fingers may be sharp and the fingers configured to find the edge of the plaque without radially cutting the intima . this “ retrograde edger ” tool is inserted through the guiding catheter placed proximal to the lesion . this tool is intended to be pulled back . it is passed beyond the lesion , deployed , then pulled back . the guiding catheter is used as a “ base station ”. the guiding catheter is in place for passing any kind of tool and does not need to be part of the various devices . the edger is passed through the lesion until after its distal edge as seen on angiography . the sheath is withdrawn to allow radial expansion of fingers , which contact the arterial wall . the guiding catheter is away from the tool ( see fig1 ) more particularly , fig1 aa and 10 bb show an “ edger ” tool generally shown by reference number 70 . edger tool 70 includes an elongated member 71 with a distal end 72 terminating in a distal tip 73 . from elongated member 71 extends one finger 74 that extends retrogradely . for example , as shown , distal tip 73 may extend in one direction and a finger distal tip 78 may extend in another direction , preferably , retrogradely relative to a direction of distal tip 73 . the relative positioning and direction of distal tips 73 and 78 may vary depending upon the positioning of finger 74 radially and / or relative to shaft 71 . finger 74 may move relatively freely and independently of shaft 71 , in the embodiment shown , and may expand in a generally radial direction . in the illustrated embodiment , finger 74 is self - expanding . radial expansion of finger 74 may be controlled by the intrinsic capabilities of the materials from which it is made and / or by external factors . for example , a slideable external sheath 75 , enables control over the radial expansion of finger 74 and thereby the degree of contact with the arterial wall and force applied to it . fig1 aa , 10 bb and 10 cc show the edger together with the sheath , which may be part of the edger device . sheath 75 is a generally elongated hollow tube with a lumen passing through it . a distal end of guiding catheter 75 may include a side opening 76 and an open end 77 . when distal end 72 of edger tool 70 is positioned in the distal end of sheath 75 , edger tool 70 may be positioned as desired relative to sheath 75 to control positioning and radial expansion of finger 74 . for example , in fig1 aa , finger 74 is positioned substantially away from side opening 76 and thereby is confined by sheath 75 so that finger 74 extends substantially alongside shaft 71 . fig1 bb shows another position of edger tool 70 in sheath 75 where finger 74 is substantially disposed in side opening 76 as such finger 74 may be free to self - expand radially away from shaft 71 . typically , during delivery , sheath 75 is positioned relative to edger 70 , such that open end 77 is proximate to finger distal tip 78 , holding finger 74 essentially alongside shaft 71 —“ closed position .” edger 70 can then be passed through the lesion and deployed distal to it by sliding sheath 75 distally , bringing open end 77 over distal end 72 —“ open position ”. sliding open end 77 back over finger 74 will gradually bring it adjacent to shaft 71 , thus controlling its angle of opening . as discussed above , edger tool may include one or more fingers . fig1 c shows an exemplary embodiment of an edger tool 79 with 3 fingers 74 a , 74 b , and 74 c . this embodiment operates similarly to that described with respect to fig1 aa and 10 bb . with three fingers or more , edger tool 79 is kept centered in the arterial lumen by force of the fingers pressing against the arterial wall all around edger 79 . this is in contrast to one finger , which may cause edger 70 to be pushed against the arterial wall opposite finger 75 . two fingers might cause the lumen &# 39 ; s cross - sectional area to decrease as the artery is expanded radially at only two points on its circumference . the fingers in accordance with the principles of the invention may include different configurations . for example , the fingers may have an overall shape and cross - section with specific profiles that enhance their ability to dissect the plaque from the arterial wall as shown in fig1 a - 10f and fig1 g - 10k . with references to fig1 a - k , the fingers are flexible elongated fingers as shown . the fingers are configured to scrape and peel , but preferably are not sufficiently sharp to cut the plaque and / or intima . furthermore , the distal tips of the fingers point towards the proximal end of the apparatus . thus , these fingers are used for removing the plaque in a backwards motion . the shape , configuration and / or radius at the finger is not sharp as for cutting , rather it is blunt or sufficient to find the edge of the plaque through scraping without cutting the intima . the fingers are designed so that radial force applied by the fingers decrease going from the proximal to the distal end of the tip ( relative to the plaque ). thus , in one embodiment , the fingers deliver more force on the proximal end of the finger and less force on the distal end . alternatively , the force may change along the fingers in a non - linear manner , for example such that it is maximal at a certain distance along the fingers . in one embodiment , the tips of fingers are parallel to the shaft , thereby approximately parallel to how it engages the artery , so that the fingers do not cut the artery . the fingers preferably extend substantially along or in the direction of the dissection plane . the fingers are also so configured that they are more rigid towards the distal end and more flexible to the proximal end . furthermore , the edges of the fingers may be relatively blunt , rounded , and / or curved so at to scrape along the plaque to find the edge and / or the separation of the plaque / layer . in one embodiment , the fingers are generally parallel to each other along their longitudinal sections . preferably , the distal end results in a device that provides for a more gentle removal of the plaque . the embodiments shown are exemplary . as discussed above , the force differences can be achieved through structure ( via e . g . use of structural features such as struts and guidewires or changing cross - section ) or function ( via e . g . use of a different materials ). the device can be used in the methods described herein , including , being scraped along the plaque to find the edge and / or the natural separation of the plaque . fig1 a - b illustrate a configuration of fingers 80 a , where each finger 80 a is generally straight upon radial expansion . this shape will easily “ dig ” under plaques on the arterial wall , as its straight edge is pointed towards them . however , it is more prone to puncture the arterial wall than are shapes described in fig1 c - f . fig1 a shows an end view of a distal end of an embodiment of an edger tool having three ( 3 ) fingers and fig1 b shows a side view of the edger tool in fig1 a . fingers 80 a are spaced radially equal distances apart on a main shaft as shown in fig1 a . fingers 80 a , when fully deployed , are at an acute angle relative to a longitudinal axis of the shaft . referring now to fig1 c and 10d , three fingers are positioned on the elongated shaft similar to fingers 74 in fig1 a - 10b , however , fingers 80 b have a different shape , they are configured in a curved shape . thus , the part applying the most force on the arterial wall is not the tip but the curvature of finger 80 b . this reduces the risk of arterial injury . referring now to fig1 e - 10f , three fingers 80 c , are positioned on the elongated shaft similar to fingers 80 a , 80 b , in fig1 a - 10d , however , fingers 80 c , are configured in a bent shape . this combines the benefits of both fingers 80 a and 80 b : the bend provides for a slightly sharper tool touching the arterial wall compared with the curved 80 b , thus improving its edging capability , while at the same time preventing penetration of the tip into the arterial wall . as discussed above , one or more fingers may be used , and the placement and configuration of each finger may vary . moreover , the placement and configuration of fingers may differ from each other on the same edger tool . fig1 g - 10k illustrate alternative embodiments for cross - sections of a hypothetical finger , embodiments of which are described herein . the cross - section is taken transversely across a distal end of a finger on an edger tool , with the direction of advancement to the left . the cross - section of the finger may vary along its length . fig1 g , 10 h , 10 j are symmetrical . they differ in their profiles . the edging action includes dissecting and wedging actions . “ dissecting ” refers to the initial penetration between the layers , and “ wedging ” refers to their separation . the wedging action is mainly dependent upon the tool &# 39 ; s wedge angle 82 . increasing this angle for a given length will increase the forces separating the plaque from the media . this will also increase the torque required to rotate the tool , therefore selection of specific tool wedge angle may be done by the physician during the procedure . fig1 g shows a cross - section of fingers having a small wedge angle , which will allow for low torque dissecting , but will be limited in the wedging action . fig1 h shows a cross - section of fingers having a larger wedge angle , which will require higher torque for the dissecting action , but will apply larger wedging forces . fig1 j depicts a finger cross - sectional shaping that is designed to reduce the required torque for the edging action . it does so by changing the wedge angle along the tool , so that a deeper penetration is achieved before the larger angled part of the finger induces the separating forces . fig1 i and 10k , both having an asymmetrical cross - sectional shaping , are examples of possible design solutions that utilize finger shaping to exert forces on the fingers , directing them towards the separation plane . the retrograde edger tool is rotated around its axis and simultaneously retracted so that the finger edges perform a spiral movement on the arterial wall . this movement gradually separates the plaque edge from the arterial wall ( fig1 ). more particularly , fig1 shows retrograde edger tool 70 in action . artery with media 10 is seen in longitudinal section , plaque 12 is shown in 3d for demonstration purposes . edger 70 has been deployed by pushing sheath 75 distally , after being passed through guiding catheter 30 and plaque 12 . edger 70 is in the fully open position , and is being rotated and pulled back thereby scraping , pealing and lifting the edge of the plaque . this is done , preferably , without cutting or damaging the artery . as an adjunct to the above , a jet of saline or other biocompatible fluid may be used to assist in the dissection , shown , for example , in fig1 - 14 . fig1 shows guiding catheter 30 in artery with media 10 seen in longitudinal section , plaque 12 in three - dimensional . jet edger tool 100 deployed with sheath 110 positioned such that fingers 101 are at fully open position . open end 111 has nozzle 112 emitting jet 115 . fingers 101 have nozzles 102 emitting jet 105 . suction tube 120 removes excess fluids . jets 115 and 105 aid in edging the plaque while edger 100 is rotated and pulled proximally . suction of excess fluid out of the blood vessel to prevent an undesirable increase in pressure may be performed through suction tube 120 as shown in fig1 . suction may be used in combination with any of the embodiments described herein . suction may be controlled either by keeping the net volume of injected fluid below a certain threshold , or by keeping the pressure in the vessel below a certain threshold . such a jet may be directed towards the arterial wall through the above - mentioned fingers as shown in fig1 a . the jet may be constant or intermittent , fixed or pulsatile . the jet may form a cross - sectional shape that is circular , elliptical or any other shape as shown for example in fig1 a - c . fig1 a shows cross - section through artery and finger , depicting media 10 and plaque 12 being separated by finger 101 , while nozzle 102 emits jet 105 . fig1 b shows circular nozzle 116 a emitting jet 105 having circular cross - section 117 a . fig1 c shows elliptical nozzle 116 b emitting jet 105 having elliptical cross - section 117 b . a jet with an elliptical cross - section may be more effective in dissection than a jet with a circular cross - section when directed at the arterial wall with its longitudinal axis parallel to the arterial longitudinal axis . such a saline jet can be used instead of the fingers as shown in fig1 . fig1 shows artery with media 10 seen in longitudinal section , plaque 12 in three dimensions . guiding catheter 30 has balloon 31 inflated . balloon 140 is placed and inflated distally . jet edger tool 131 has nozzle 132 emitting jet 135 . suction tube 120 removes excess fluids . jet 135 edges and dissects the plaque while edger 100 is rotated . in this embodiment , both edging and dissection may be performed by jet only , while the treated area is isolated between the two balloons . alternatively , a similar jet edger tool may be used in anterograde fashion , when passage through the lesion is not possible , for example on a lower limb . distal isolation may be achieved by external compression of the limb . mixing contrast material with the jet fluid can enable angiographic visualization of the progression of subintimal dissection . the tools described herein may be used under direct vision by endoscopy or other visualization method , as can optionally be done with all the edger and dissection tools described herein . an alternative embodiment of the edger tool pertains to the structure of the fingers . as shown in fig1 , the fingers can be made of looped metal wires , or a laser cut metal tube or sheet . fig1 shows wire 150 bent at point 151 , with both ends returning to the base 152 . alternatively , the edger fingers can be made of metal tubes through which are passed metal wires . fig1 a shows such metal tube 160 , compressed at its distal tip 161 , and metal wire 162 extending therethrough . 16 b is the same finger with wire loop slightly more distally extended . this structure can enable combining both edger and dissector into one tool , such that after edging is performed , the wire loops 162 can be extended into the sis from the edges 161 of the fingers 160 . an alternative approach to entering the sis is based on an intentional cut of the intima , proximal to the lesion . this can be done using a specialized tool with a blade of predetermined depth . this is shown in fig1 : catheter 30 with balloon 31 in artery with media 10 and normal intima 11 proximal to lesion 12 . proximal intima cutting tool 170 includes a metal strip having elongated shaft 171 , which curves into a radial part 172 oriented circumferentially from which a distally inclined blade 173 of height 174 protrudes radially . sheath 175 , which covers the tool before deployment , is retracted to enable its expansion and contact with intima 11 . rotation of proximal intimal cutter 170 several times cuts a thin incision through the intima . the tool 170 is covered by sheath 175 and removed . this can later be followed by deployment of radially expansive dissector tool , which when expanded radially and advanced distally , find its way into the incision , and enters the sis or an adjacent dissection plane within the media . another aspect of the invention is a dissector tool . dissection and advancement of the dissector may be aided by vibration that may be applied to the tool , and / or saline jet dissection as previously described . an example of a tool intended for separating the rest of the plaque from the arterial wall is shown in fig1 a and 18b . this embodiment includes a cylindrical bag , which is rolled up or folded into a ring . the ring is mounted on an elongated member . the bag has longitudinal inflatable strips in it that can be inflated through the external edge of the elongated member . the tool is placed in the artery via the guiding catheter . the ring is inserted between the plaque and media of the artery , preferably over the edger tool . inflation of the longitudinal strips causes the bag to open and lengthen while dissecting between the plaque and media . this and additional similar embodiments are depicted in fig1 c in side view . more particularly , in fig1 a - b , dissection tool is shown generally at 180 . fig1 a is a three - dimensional view of the device while fig1 b is a longitudinal section through the artery and device . fig1 a shows inflatable dissection tool 180 which has longitudinal inflatable strips 183 configured in a funnel shape when inflated . the ends of the strips face inwards . the inflatable dissection tool further includes longitudinal bag 181 which is surrounded by the longitudinal inflatable strips 183 and folded bag 182 which is towards the distal end of the tool 189 . the folded bag 182 may be integral with longitudinal bag 181 . fig1 b shows media 10 , plaque 12 , already slightly separated at edge by edger tool . with reference fig1 b , inflatable dissection tool 180 is depicted with its longitudinal bag 181 in the lumen and the folded bag part 182 in the sis . once the longitudinal strips are inflated , the device unfolds while dissecting further between the layers . fig1 c - f show alternate embodiments of a distal end of dissection tools as described above with reference to fig1 a - b . fig1 c shows dissection tool 180 described above . fig1 d shows another aspect of a dissection tool 180 a . this device is identical to 180 except the direction of folds is inwards instead of outwards . compared to 180 a , tool 180 has the advantage of pushing the media outwards , whereas tool 180 a pushes the intima inwards towards the plaque , which causes more resistance . fig1 e shows another aspect of a dissection tool 180 b . this tool is folded as a harmonica fashion instead of being rolled . fig1 f shows another aspect of a dissection tool 180 c . both 180 b and 180 c encounter less resistance to unfolding than do 180 and 180 a , however , the method of making the folds is simpler in the rolled up devices 180 and 180 a . importantly , devices 180 and 180 a can be made of braided stents instead of a polymer bag . instead of using inflation , they can be unfolded for example by pushing the folded ring forward at several points with wires extending proximally through the guiding catheter . with regard to the distal intimal cutting tool , there are several additional embodiments . the distal intimal cutting tool 60 previously described may be inserted through a specialized groove located in the wall of the guiding catheter ( fig1 a - b ). 19 a shows cross - section of multi - lumen guiding catheter 190 with catheter main lumen 191 and cutting tool groove 192 . fig1 b shows a longitudinal section of the artery with cutting tool 60 extending from groove , inserted between media 10 and dissector tool 50 , and cutting intima 11 at plaque edge . alternatively , the cutting tool may be inserted through lumen 191 over or instead of dissector . another approach to cutting the intima at the edge of the lesion is based on the shape memory properties of the nitinol wires including dissector 200 , shown in fig2 a - d . fig2 a shows dissector 200 having one or more dissector tip 201 at the distal end and loopwires 202 , which is identical to dissector 50 , apart from having been thermally treated to assume a thermally dependent conformation change . at normal body temperature , the dissector has a slight outward angulation of tip 201 . fig2 b shows dissector after being heated / cooled — the angulation changes towards the interior of the lumen . fig2 c - d show same in arterial longitudinal section . this change in angulation inwards can cause re - entry of the loops into the lumen . alternatively , a needle may be extended from the edge of one of the loops , and after its entry into the lumen , a guide wire can be passed through it . in some embodiments of the cutting tool , there are multiple tools on the dissector , each slideably attached to a loop &# 39 ; s centerline . this allows for cutting around the whole intima with partial rotation of the dissector . after cutting and blade retraction , the cutting tools can be pushed forward such that they bend towards the center of the lumen and form a wall that assists in holding the plaque as it is pulled back and removed . this approach is based on threading a guidewire through the subintimal space from one end of the plaque to the other , then using a tool , which expands along this space , thus peeling the plaque from the arterial wall . this is intended to peel the plaque , which includes the intima , while leaving the media and adventitia intact . sometimes , especially if the plaque involves the media , some medial layers might be peeled as well . however , this should not pose a major problem , as it often occurs during surgical endarterectomy , and does not cause any complications . an embodiment of this approach is shown in fig2 - 23 . a guidewire is introduced into the subintimal space and advanced along the lesion and beyond its far end , then back into the lumen . a separator device such as that shown in fig2 ( in its deployed state ) is introduced over the wire ( in its folded , non - deployed state ). this tool includes a hollow cylinder with a longitudinal slit , folded onto an elongated member . when deployed , it assumes its cylindrical shape with an overlap of both ends over the slit . this can be achieved for example by an inflatable balloon constructed of multiple longitudinal chambers having a trapezoid cross - section and connected to each other side by side . as the balloon is inflated , it dissects around the plaque , separating it from the arterial wall and encompassing the dissected plaque . more particularly , with reference to fig2 a , a three - dimensional view of artery with deployed device 210 is depicted . guidewire 211 inside device catheter 212 is seen intraluminally , then passes via intima 11 into subintimal space (“ sis ”) 214 , and is again seen intraluminally 213 distal to lesion . fig2 b is a cross - section of device 210 , folded balloon 215 , catheter 212 , and bilateral longitudinal radiopaque markers . the device may optionally have one or more longitudinal markers 216 . with reference to fig2 a - f , the stages of this procedure are depicted . fig2 a and 22b are longitudinal and transverse views of non - deployed device 210 passed over guidewire 211 in sis , traversing lesion 12 . fig2 c and 22d are longitudinal and transverse views of device 210 partially deployed . fig2 e and 22f are longitudinal and transverse views of device 210 at full deployment , encompassing lesion 12 . fig2 is a three - dimensional view of the deployed device 210 with catheter 212 . prior to deployment , angiography can be used to ascertain the device is at the optimal orientation for deployment . radiopaque markers 216 must be demonstrated parallel to each other at the medial border of the plaque . during deployment , the markers may be seen moving across the lumen to encompass the lesion . after the device is fully deployed , a distal intimal cutting tool 60 can be used to free the connecting intima . such tool 60 may either be integral with the dissector 210 , or a separate tool used in combination with 210 . alternatively , a similar device 220 may be formed of transverse longitudinal strips , each having a slight curvature , such that when inflated the device assumes a flat shape , with only slight radius of curvature . this increases the tendency of the dissector to inflate within the sis without encroaching on the arterial lumen . fig2 is a 3d view of the flat device 220 with catheter 222 . a different embodiment shown in fig2 a - c is based on a nitinol device composed of multiple arched wires stemming off both sides of a central longitudinal spine . a sheath covers those “ ribs ” holding them flatly adjacent to the spine . when the sheath is removed , the ribs dissect around the plaque and form a cage encircling it . more particularly , fig2 a shows device 230 at 3 d . fig2 b shows a side view of device 230 shown in fig2 a . fig2 c shows and end view of device 230 in fig2 a . ribs 232 extend laterally from spine 231 the above described devices 210 , 220 and 230 , which dissect and contain the plaque , may have a predetermined shape such that their distal end is closed . this allows for containment of the dissected plaque inside such structure , which prevents debris from embolizing . alternatively , the distal end only or both ends may be closed for example by a wire traversing that end in a “ purse - string ,” which wire can be tightened by pulling on such wire . inflating a balloon or deploying a nitinol web at the open end are additional ways for closing the aperture . removal of the freed plaque from the body can be achieved in several ways . if the volume of plaque is not very large , it may be possible to remove the plaque as is within the containment structure through the introducing sheath and outside of the artery . however , in some cases the plaque will be too large for such removal , and will need to be ground into small pieces . grinding the plaque can be done by a grinder mounted on a catheter , with a suction catheter as part of the same tool or used in conjunction with it . if the proximal end of the containment structure holding the plaque has been closed , it will need to be penetrated by such catheter to contact the plaque . a useful addition to the above is a modification for preventing clogging of the grinder device . in cases where the freed plaque was not contained in a bag or chamber , balloons should have been inflated on both sides of the work area to isolate it . grinding and aspiration of the plaque can take place in this isolated area , followed by rinsing of the space with saline to ensure removal of all debris . in some embodiments , after plaque removal , the treatment area is isolated between balloons and flushed with isotonic fluid in rapidly changing directions and pressure , in order to wash away any residual loosely adherent plaque , intima , or medial tissue . alternatively or in addition , a fogarty catheter may be passed over the treated in a gentle manner . other methods of ensuring removal of residuals include angiography , ivus , or visual inspection . following completion of the percutaneous atherectomy using the methods and devices described above , the next stage of treatment begins . fig2 shows device 400 situated across area 500 where lesion was removed . device 400 is a multilumen catheter intended for isolation of the treated area and delivery of medial layer therapy . catheter 400 has lumen 401 for blood flow across isolated area 501 . lumen 402 inflates proximal balloon 412 , lumen 403 inflates distal balloon 413 . lumen 404 serves for inflow of therapy and lumen 405 for outflow . in use , proximal balloon 412 and distal balloon 413 are inflated . blood passes freely through the blood flow lumen . treatment may be delivered according to the specific protocol — e . g . perfusion with saline or blood , and instillation of the treating agent — usually endothelial progenitor cells . the treatment continues for the required duration . the area is flushed with saline and refilled with the patient &# 39 ; s blood , the balloons are deflated , and catheter 400 removed . another aspect of the current invention includes devices for insertion of guidewires into the sis . such a device intended for non - cto lesions is shown in fig2 a - b and includes a multilumen catheter , proximal and distal balloons , a suction lumen , and a catheter for passing a guidewire extending across the periphery of the proximal balloon . fig2 a is a longitudinal section through artery and device 250 showing device catheter 251 , proximal balloon lumen 252 , distal balloon lumen 253 , suction lumen 254 , guidewire catheter 255 , guidewire 256 , proximal balloon 257 , distal balloon 258 . fig2 b is a front view of same device . in use , device 250 is brought proximate to the plaque edge such that distal balloon 253 is within lesion . proximal balloon 257 is inflated , followed by distal balloon inflation . inflation of the balloons produces a force pushing the plaque distally and normal artery proximally , as well as an outward force on the arterial wall proximal to the lesion . these forces apply tension on transition zone 259 between “ normal ” intima 10 proximal to the lesion and plaque 12 . the pushing force between the plaque and proximal artery may be increased by making distal balloon 253 moveable forward relative to guidewire catheter 255 . the guidewire catheter is compressed against the arterial wall by the proximal balloon , and assumes an angle up to approximately 5 degrees outwards of the longitudinal arterial axis , leading the guidewire towards transition zone 259 . optionally , suction may be applied to the suction lumen , reducing the pressure in the area between the balloons and pulling the plaque away from the arterial wall towards the center of the lumen . the combination of increased tension in transition zone 259 , exact direction of the guidewire towards transition zone 259 , and pulling of plaque 12 away from arterial wall 10 , facilitates entry of guidewire 256 through transition zone 259 into sis . in another embodiment , a similar device 270 is provided for insertion of multiple guidewire around the lesion . fig2 c shows device 270 having device catheter 271 in front view with four guidewire catheters 275 a - d leading four guidewires 276 a - d into the sis in the same manner described for device 250 . for cto lesion or other lesions where a balloon cannot be inflated to within the lesion , a similar device is provided which uses an umbrella - like contraption instead of the distal balloon . fig2 a illustrates this device in an artery &# 39 ; s longitudinal section . with reference to fig2 a , device catheter 291 is shown having proximal balloon lumen 292 and umbrella and suction lumen 293 . the umbrella 294 is shown passing through the lumen of the device catheter 291 . guidewire catheter 295 containing guidewire 296 also passes the lumen of the device catheter 291 . umbrella 294 has umbrella distal end 298 fig2 b shows a front view of the catheter device and 27 c a front view of the umbrella device . in use , device 290 is brought proximate to the plaque edge . proximal balloon 297 is inflated , followed by deployment of umbrella 294 . inflation of the proximal balloon and pushing umbrella 294 forward produces a force pushing the plaque distally and normal artery proximally , as well as an outward force on the arterial wall proximal to the lesion . these forces apply tension on transition zone 299 between “ normal ” intima 10 proximal to the lesion and plaque 12 . the guidewire catheter is compressed against the arterial wall by the proximal balloon , and assumes an angle up to approximately 5 degrees outwards of the longitudinal arterial axis , leading the guidewire towards transition zone 299 . optionally , suction may be applied to the suction lumen , reducing the pressure in the area between the proximal balloon 297 and plaque and pulling the plaque away from the arterial wall towards the center of the lumen . the combination of increased tension in transition zone 299 , exact direction of the guidewire towards transition zone 299 , and pulling of plaque 12 away from arterial wall 10 , facilitates entry of guidewire 296 through transition zone 299 into sis . in yet another embodiment , a device based on the edger tool 20 can be used to deliver guidewires to the sis . one or more guidewire catheters are attached to fingers 21 of edger , such that when edger fingers enter sis or are proximate to it , pushing forward the guidewires will result in their entry to the sis . multiple such guidewires in the sis can be used as a dissection means for short plaques or as a lead for insertion of a dissector too . another embodiment of the invention is described in fig2 . this embodiment involves use of an anvil - like tool , which is placed distal to the lesion in order to assist with the distal intimal cutting stage . more particularly , fig2 shows a longitudinal section of artery with media 10 , plaque 12 , guiding catheter 30 anchored by balloon 31 . anvil 600 is a cylindrical tool including body 601 continuous with elongated shaft 602 , and several wings 603 each with distal tip 604 and distal edge 605 . wings 603 are formed such that when deployed , wings 603 flare outwards and distal edges 605 form an essentially continuous circumferential line around the inside of the lumen of the artery . wings 605 may optionally be covered by web 606 . also provided is cap 610 including body 611 and elongated shaft 612 . body 611 is cylindrical and continuous with elongated shaft 612 . cap 610 can be pulled to cover anvil 600 , which folding wings 603 towards the elongated shaft 602 . elongated shaft 612 is threaded through elongated shaft 602 , and both parts are passed through the guiding catheter 30 , optionally over guidewire 620 . in use , anvil 600 is passed through guiding catheter 30 and inside lesion 12 , and deployed distal to it by pushing cap 610 distally , such that anvil distal edges 605 press against the arterial wall and cause it to bulge outwards slightly . web 606 of anvil 600 may then act as an emboli protection device . edging or proximal intimal cutting is then performed in a manner similar to that described for previous embodiments , and dissection tool 50 is passed in guiding catheter 30 over elongated shaft 602 and through sis until it reaches the distal plaque edge . at this point , pushing dissection tool 50 forward will cut intima between anvil distal edges 605 and loop centerlines 53 . cap 610 can then be pulled back to slightly close anvil 600 and dissector 50 to enable removal of all instruments together . using the anvil tool enables anchoring of the intima to the media during distal cutting , thus preventing or reducing the risk of creation of an intimal flap . it is clear to anyone familiar with the art that the above described devices and methods can be used in any other organ in the body that has an elongated lumen such as the gastrointestinal tract , pulmonary system , urinary system etc . potential alternative applications of the above include but are not limited to biopsies , removal of tumors or pathological tissues . although the foregoing description is directed to the preferred embodiments of the invention , it is noted that other variations and modifications will be apparent to those skilled in the art , and may be made departing from the spirit or scope of the invention . moreover , features described in connection with one embodiment of the invention may be used in conjunction with other embodiments , even if not explicitly stated above . the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics . the described embodiments are to be considered in all respects only as illustrative and not restrictive .
devices and methods are provided for percutaneously treating atherosclerotic plaques within blood vessels . atherosclerotic plaques cause significant morbidity and mortality by narrowing the arteries , which adversely affects blood flow , and by acting as a source for thrombi and emboli thus causing acute organ ischemia . current treatments include open surgery with its inherent drawbacks , and stenting , which is less invasive but leaves the plaque material in the artery , which promotes restenosis . the present invention combines the advantages of both approaches . in general , the invention provides tools that enable percutaneously dissecting the plaque from the arterial wall and removing it from the body .