the following detailed description should be read with reference to the drawings , in which like elements in different drawings are identically numbered . the drawings , which are not necessarily to scale , depict selected preferred embodiments and are not intended to limit the scope of the invention . the detailed description illustrates by way of example , not by way of limitation , the principles of the invention . this description will clearly enable one skilled in the art to make and use the invention , and describes several embodiments , adaptations , variations , alternatives and uses of the invention , including what is presently believed to be the best mode of carrying out the invention . according to one embodiment of the present invention , a first phase in creating a native fistula is the transection of a desired vein using an appropriate cutting device . in one variation , the vein transecting device employs a cylindrical cutter to slice through the vein wall from within the vein , allowing for minimal surgical invention . as illustrated in fig1 - 3 , a catheter 10 is inserted through a small incision 18 into a patient &# 39 ; s vein 12 in the forearm or wrist 16 thereof in a direction 14 towards the patient &# 39 ; s fingers . in this example , an occlusion device 20 is inserted through catheter 10 to occlude the vein as shown in fig2 , and a cutter 22 is inserted through the catheter 10 to perform the transection , as shown in fig3 . the forward end 24 of the catheter is closed to protect the cutter 22 , and opened as shown in fig3 when the cutting is to commence to expose the cutter . suction or vacuum may be applied through the catheter to pull the vein wall towards the cutter , and the cutter rotated in either direction , such as in the direction of arrow 26 , to sever the vein in the desired location . the suction or vacuum which may be applied , may be applied through an inner lumen of the catheter shaft and serves to pull the vein into the path of the rotating , cylindrical cutter . the procedure for transecting a vein is further illustrated in fig7 and 8 , which show a detailed view of a representative cutter 100 , vein 102 , catheter shaft 104 , cutting means 106 and anvil 108 . in the cutter open position shown in fig7 , vacuum or suction is applied through the catheter shaft 104 via vacuum or suction means 114 , shown schematically , to pull the vein 102 inward . the cutting means 106 is rotated , such as in the direction of arrow 110 shown in fig8 , to cut the vein against the anvil 108 and to retract the cutter against the anvil . the vacuum or suction means is then shut off and the cutting device removed from within the vein in the direction of arrow 112 , possibly with the cutting device including a cut segment of the vein . the resultant cut vein has two cut portions , first cut end portion 102 a and second cut end portion 102 b , as can be seen in fig8 . a second phase in creating a native fistula is to make a connection between the cut vein and an artery , which is illustrated in fig4 - 6 . a cut end of the vein , such as cut end portion 102 a , is brought into contact with a selected artery , such as artery 30 shown in fig4 . as mentioned , it is advantageous that the vein and artery be adjacent each other ; however , it should be understood that a connection can be made between a separated vein and artery not adjacent to one another by stripping away connective tissue from the vein and relocating the position of the vein . fig4 illustrates a side - to - side connection , although certainly an end - to - side connection is also possible and contemplated by the present invention . the first cut end 102 a of vein 102 is mobilized with catheter 32 , and the artery 30 is accessed with catheter 34 . if desired , a light 33 can be provided at the end of catheter 34 that is visible through the skin , and also at the end of catheter 32 , if desired , in order to assist in locating or aligning the vein with respect to the artery . naturally , other alignment means or visualization techniques know to one of skill in the art can be used , including fluoroscopy , radiopaque markers , ultra - sound , etc . in one variation of the present invention , radiofrequency ( rf ) energy is utilized to heat and fuse the vessels together . tissue welding can be accomplished with heat and pressure between two collagen structures . the vein and artery outer layers or adventitia are composed primarily of collagen . when heated to between about 50 ° c . and 100 ° c . the collagen protein is denatured which allows it to be reformed or fused together . in addition , the strong fascia between the vein and artery is collagen , which is quite pronounced in the wrist area , and provides a welding medium to assist in achieving a better bond . thus , as shown in fig5 , a vein electrode catheter 36 may be introduced into the first cut end 102 a and an artery electrode catheter 38 may be introduced into artery 30 to perform an anastomosis between the first cut end 102 a and artery 30 . in one variation , this procedure includes the occlusion of the free end of first cut end 102 a at first end portion 40 , followed by the creation of a lumen 42 by connecting first cut end 102 a of vein 102 with artery 30 along the sides thereof . the final structure can be seen in fig6 . rf energy may also be used to occlude the second end portion 44 of second cut end 102 b ( fig8 ). fig9 and 10 show vein electrode 32 and artery electrode 34 , with fig9 showing the electrodes in position in vein 102 first cut end 102 a and in artery 30 , and fig1 showing the electrodes removed from the vessels with insulation 46 thereover . alignment means may be provided on the rf electrodes to aid in alignment for the anastomosis , as for example post 48 on electrode 32 and opening 50 on electrode 34 . naturally other alignment means can be provided and are within the scope of this invention . rf energy at a frequency of from approximately 400 to 600 khz , and generally at a frequency of about 500 khz , is used in one embodiment of the present invention . in one variation , bi - polar rf energy is utilized and the desired tissue is simply positioned between the two electrodes as shown . the current flows from one electrode , through the tissue which has a resistance , to the other electrode . the resistance of the tissue produces the heat which fuses the tissues together and also forms the desired lumen . pressure may be applied between the electrodes . following the procedure , pressure is released after a cooling period and the electrode catheters are withdrawn , leaving the vein attached to the artery . thus , the present invention advantageously transects the vein in a simple , convenient manner , and bonds the vein to the artery and forms a lumen therebetween , also in a simple and convenient manner . this invention has been described and specific examples of the invention have been portrayed . while the invention has been described in terms of particular variations and illustrative figures , those of ordinary skill in the art will recognize that the invention is not limited to the variations or figures described . in addition , where methods and steps described above indicate certain events occurring in certain order , those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the invention . additionally , certain of the steps may be performed concurrently in a parallel process when possible , as well as performed sequentially as described above . therefore , to the extent there are variations of the invention , which are within the spirit of the disclosure or equivalent to the inventions found in the claims , it is the intent that this patent will cover those variations as well .
method and device for cutting a blood vessel using a cutting tool from within the blood vessel . a first cut portion of the blood vessel is fused to a second blood vessel to provide a flow channel therebetween .