the following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same . the drawings , which are not necessarily to scale , depict illustrative embodiments and are not intended to limit the scope of the invention . referring to fig1 , a diseased heart 100 includes a chronic total occlusion 101 of a coronary artery 102 . fig2 shows coronary artery 102 with intimal layer 200 ( for sake of clarity , the multi layer intima is shown as a single homogenous layer ). concentrically outward of the intima is the medial layer 201 ( which also is comprised of more than one layer but is shown as a single layer ). the transition between the external most portion of the intima and the internal most portion of the media is referred to as the subintimal space . the outermost layer of the artery is the adventitia 202 . in an aspect of the disclosure , a subintimal device may be used to guide conventional devices ( for example guide wires , stents , lasers , ultrasonic energy , mechanical dissection , or atherectomy ) within the vessel lumen . additionally , a subintimal device may be used to delaminate vessel wall layers and also may be used to remove tissue from the occlusive lesion or surrounding vessel wall . in one embodiment , fig3 shows a subintimal device directing catheter is 300 with its distal balloon 301 that has been advanced over a conventional guide wire 302 and inflated proximal to chronic total occlusion 101 . for the sake of clarity , fig3 shows a subintimal device path that is substantially parallel to the vessel lumen , but other orientations ( i . e . helical ) may also be considered . subintimal device lumen 303 is positioned adjacent to the intimal layer 200 and subintimal device 304 has been advanced as to perforate the subintimal layer . a fluid source ( i . e . syringe ) 305 is in fluid communication with subintimal device lumen 303 through infusion lumen 306 . fluid may flow from the fluid source 305 through the subintimal device lumen 303 under a controlled pressure or a controlled volume . the infused fluid may enter the subintimal space 307 directly from the subintimal device lumen 303 or from the volume 308 defined by the distal end of the balloon 301 and the proximal edge of the lesion 101 . fig4 shows an alternative fluid infusion path where fluid source 305 is in fluid communication with a lumen within the subintimal device 304 . fig5 shows an alternative subintimal device directing guide catheter 500 where the distal end 501 has a predefined shape or the distal end has an actuating element that allows manipulation by the physician intra - operatively . another aspect of the disclosure may place a subintimal device within the subintimal space in a first collapsed configuration and releases or actuates the subintimal device to a second expanded configuration . the device may then be withdrawn or manipulated to propagate the subintimal dissection . in one embodiment , fig6 a shows a subintimal device with internal expandable element 600 that contains one or more expanding elements 601 contained in exterior sheath 602 . fig6 b shows exterior sheath 602 in a retracted position allowing expanding elements 601 to elastically expand . the subintimal device is intended to be delivered through the aforementioned subintimal device delivery catheters . an additional aspect of the disclosure may allow the physician to remove tissues from the lesion or vessel wall . fig7 a shows an embodiment where subintimal device directing balloon catheter is inflated within coronary artery 102 just proximal to chronic total occlusion 101 . subintimal device 304 is partially delivered around chronic total occlusion 102 coaxially outside the intimal layer 200 and coaxially inside medial layer 201 in a helical pattern . fig7 b shows a subintimal device capture catheter 702 positioned across the chronic total occlusion 101 over conventional guide wire 703 and within subintimal device 304 . the distal 704 and proximal 705 ends of the subintimal device 304 have been captured and rotated as to reduce the subintimal device outside diameter and contain the lesion 101 and intima 200 within the coils &# 39 ; internal diameter . the device may be withdrawn through the use of a cutting element . for example , fig7 c and d show the advancement of a cutting element 706 in two stages of advancement showing the cutting of intima 200 proximal of the occlusion 707 and intimal distal of the occlusion 708 . an additional aspect of the subintimal device is the construction of the device body . the flexibility and torquability of the device body can affect the physician &# 39 ; s ability to achieve a subintimal path . the subintimal device body may be constructed in part or in to total of a single layer coil with geometric features along the coil length that allow adjacent coils to engage ( for example mechanical engagement similar to the teeth of a gear ). fig8 a shows coil 801 closely wound such that the multitude of teeth 802 along the coil edges are in contact such that the peaks of one coil falls within the valleys of the adjacent coil . a conventional coil reacts to an applied torsional load by diametrically expanding or contracting , thus forcing the wire surfaces within a turn of the coil to translate with respect to its neighboring turn . the construction of coil 801 resists the translation of wire surfaces within the coil thus resisting the diametric expansion or contraction ( coil deformation ). an increased resistance to coil deformation increases the torsional resistance of the device body while the coiled construction provides axial flexibility . an exemplary construction may include a metallic tube where the coil pattern 801 and teeth 802 are cut from the tube diameter using a laser beam . fig8 b shows subintimal device body 804 that is for example a continuous metallic tube with distal laser cut coil segment 801 and proximal solid tube 803 . tube materials include but are not limited to stainless steel and nickel titanium . alternatively , the coil may be wound from a continuous wire . the wire has a cross section that for example has been mechanically deformed ( stamped ) to form the teeth and allow coil engagement . fig8 c shows an example of a laser cut tooth pattern from the circumference of a tube that has been shown in a flat configuration for purposes of illustration . in another embodiment , a tissue removal device may be passed through the lesion within the native vessel lumen . fig9 a shows corkscrew device 900 with exterior sheath 902 engaging occlusion after delamination of the intimal layer 901 has been performed by the aforementioned methods and devices . fig9 b shows removal of the occlusion and a portion of the intimal layer through axial withdrawal of the corkscrew device . from the foregoing , it will be apparent to those skilled in the art that the present invention provides , in exemplary non - limiting embodiments , devices and methods for the treatment of chronic total occlusions . further , those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein . accordingly , departures in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims .
devices and methods for the treatment of chronic total occlusions are provided . one disclosed embodiment comprises a method of facilitating treatment via a vascular wall defining a vascular lumen containing an occlusion therein . the method includes providing an intravascular device having a distal portion , inserting the device into the vascular lumen , positioning the distal portion in the vascular wall to at least partially surround the occlusion , and removing at least a portion of the surrounded occlusion from the lumen .