as shown in the exemplary drawings and for purposes of illustration , the invention is embodied in a device and method for introducing medical devices within vasculature . in one aspect , the introducer includes a hub , a peel - away sheath , and an inner member or dilator , and has associated therewith a method of introducing the same into vasculature . the present invention involves facilitating the introduction of a plurality of wires ( for example , two guidewires or a guidewire and a medical device manipulation wire ) within vasculature and the expedient removal of the dilator of the invention from within vasculature . it is contemplated that the present invention includes a hub with multiple lumens which operates to separate wires or other therapeutic or diagnostic devices to thereby avoid entanglement and a dilator configured with longitudinally extending grooves which facilitate its easy removal from vasculature . referring to fig1 the introducer 20 includes a hub 21 with dual lumens 25 , 26 , a dilator or inner member 23 , and a generally tubular sheath 22 with sheath handle 24 . the proximal end of the dilator 23 is joined ( not shown ) to the hub 21 . the sheath 22 is slid over the dilator 23 and the sheath handle 24 is locked to the hub 21 . in a preferred embodiment , the sheath 22 extends distally along the dilator 23 to a point 41 just proximal of the terminal end 31 of dilator 23 . additionally , the sheath 22 includes a pair of weakened areas consisting of longitudinally extending perforations or recesses 42 that are spaced 180 ° degrees circumferentially apart on the sheath . alternatively , a single weakened area could be used . the perforations or recesses 42 on the sheath extend longitudinally through a circular knob 28 ( see fig2 a and 2b ) at the proximal end of the sheath where it is bonded to the sheath handle 24 and also along a midline 43 of the sheath handle 24 . as will be described below , it is intended that the sheath handle 24 can be fractured about a midline 43 and oppositely directed forces applied so that the sheath splits along the perforation or recess 42 . referring now to fig2 a and 2b , the introducer 20 further includes a locking post 40 . additionally , the sheath 22 further includes the circular knob 28 at its proximal end . when the sheath is slid over the dilator 23 , the sheath handle 24 is held generally perpendicular to a longitudinal axis of the dilator 23 and locked to the hub 21 by turning the sheath handle 24 and placing it proximal to the locking post 40 . the circular knob 28 operates to facilitate securing the sheath handle 24 against the locking post 40 . with the sheath 22 locked to the hub 21 , the device can be introduced into the vasculature as a single assembly . when the sheath 22 is unlocked from the hub 21 , for example by turning the sheath handle 24 in a counter - clockwise direction , the hub 21 and dilator 23 can be maneuvered as a separate unit from the sheath 22 , thereby allowing the dilator 23 to be removed from the vasculature independent of the sheath 22 . the sheath 22 can be peeled - away , as stated , by snapping the ends of the sheath handle 24 ( see fig1 ). in one aspect of the invention , the dual lumens 25 , 26 of the hub 21 each have a slit 27 extending in a distal direction . the slits 27 allow the wires ( not shown ) to be expediently disengaged from the hub 21 by pulling them in a direction that is transverse to the hub 21 . referring now to fig3 to 4 b , the dual lumens 25 , 26 are separated at a proximal end 44 of the hub 21 by a center wall 29 and converge to a single lumen 30 at a distal end 45 of the hub 21 where dilator ( not shown ) is joined to the hub 21 . the dilator maintains separation of the wires at the distal end of the hub . in a preferred embodiment of the invention , each of the dual lumens 25 , 26 can accommodate a wire up to approximately 0 . 035 ″ ( 0 . 89 mm ) in diameter . moreover , the sheath length is contemplated to be about 45 cm with a diameter of about 10f ( 3 . 3 mm ). the dilator itself can be from 16 to 45 cm long . the hub , sheath and dilator are made of medical grade polymers , such as a polycarbonate or polyurethane material . it is anticipated that alternate embodiments of the invention could have more than two lumens , with adjustments in allowable wire or other therapeutic or diagnostic device diameter . as shown in fig5 to 13 , the dilator or inner member 23 contains two grooves 32 , 33 that run nearly the entire length of the dilator 23 . when the sheath 22 is placed over the dilator 23 , its inner wall forms a lumen with each of the grooves 32 , 33 for receiving a wire ( not shown ). when the sheath 22 is removed or the dilator 23 retracted from the sheath 22 , the grooves 32 , 33 permit the dilator 23 to be slipped off the wires without having to retract the dilator 23 the entire length of a particular wire . the groove 32 narrows and is much smaller in the tapered terminal end 31 of the dilator 23 such that the tapered terminal end 31 does not easily slip off a wire as with other portions of the groove , but must be peeled off . in a preferred embodiment ( fig6 and 7 ), one of the grooves 32 extends to a point 35 at the tapered terminal end 31 of dilator 23 , while the other groove terminates at a point 34 proximal to the tapered terminal end 31 of the dilator 23 . in this instance , the dilator tip forms a lumen for the primary guidewire . the dilator tip forming the lumen is scored to allow removal from the guidewire . in an alternate embodiment of the invention ( fig6 - 9 ), the terminal end 31 of the dilator 23 can be made more flexible than the shaft so that the tip is atraumatic . additionally , in alternative embodiments , the dilator 23 may have as many grooves as necessary for the intended application . moreover , as shown in fig8 and 9 , both grooves 132 , 133 can be configured to extend to points 134 , 135 , respectively , near the terminal end of the dilator 23 . fig1 to 13 show alternate embodiments in which the terminal end 131 of the dilator 23 is rounded rather than tapered . turning now to fig1 to 19 , steps in one anticipated use of the invention is shown . using a standard percutaneous technique , a guidewire 51 is placed within vasculature and advanced to a target site using fluoroscopy . with the guidewire 51 extending from the body as shown in fig1 , the dual lumen peel - away introducer 20 , with the sheath 22 locked to the hub 21 , is then fed over the guidewire 51 . to accomplish this , the guidewire 51 is placed within the dilator groove 32 and through the lumen created by the inner wall of the sheath 22 and dilator groove 32 until the guidewire emerges proximally from one of the dual lumens 25 of the hub 21 as shown in fig1 . the second guidewire 52 is then inserted into the other of the dual lumens 26 of the hub 21 and advanced distally through the lumen created by the inner wall of the sheath 22 and dilator groove 33 until it reaches the distal end of the dilator 31 as shown in fig1 . the dual lumen peel - away introducer 20 and second guidewire 52 are then advanced simultaneously along the first guidewire 51 to a desired position in the vasculature as shown in fig1 . alternatively , the introducer can be advanced to the desired position before the second guidewire 52 is advanced through the second lumen 26 . significantly , the introducer 20 is designed to have a length that is sufficient to extend from an entry point of a patient &# 39 ; s vasculature to the aortic bifurcation , for example . once the desired position in the vasculature is reached , the hub 21 and dilator 23 can be removed , leaving the sheath 22 in place in the vasculature . it is to be recognized , however , that depending on the application , the sheath 22 can be removed first leaving the dilator 23 in place in the vasculature . to withdraw the sheath 22 , the sheath handle 24 can be moved in a counterclockwise direction to unlock it from the hub lock 40 . then , holding the sheath handle 24 and guidewires 51 , 52 steady , the hub 21 is pulled proximally to retract the dilator 23 as shown in fig1 . alternatively , the entire device may be retracted from the vasculature and removed from the wires outside the body . when the terminal end 31 of the dilator 23 exits the proximal end 55 of the sheath handle 24 , the dilator 23 is removed by sliding it off the first guidewire 51 via groove 32 and off the second guidewire 52 via groove 33 . the guidewires 51 , 52 can be removed from the hub 21 by pulling them transversely through the slits 27 . the first guidewire 51 is separated from the dilator tip through the score at the tip . the two guidewires 51 , 52 are now free to be utilized for subsequent medical steps . the sheath 22 can be removed as desired by snapping down on the tabs 56 that form the sheath handle 24 and circular knob 28 while the sheath is pulled from the vasculature , thereby causing it to fracture into two pieces . by continuing to apply oppositely directed forces to the fractured pieces of the handle 24 , the sheath 22 will split along the pair of perforations or recesses 42 to thereby peel - away from the guidewires 51 , 52 as shown in fig1 . as will be readily apparent to one of skill in the design of medical device introduction systems , the medical device introduction system of the present invention may be incorporated in various forms of dilators and peel - away sheaths . in addition , while the foregoing discussion of the embodiment of the device introduction system illustratively employed two wires , a greater or lesser number of wires may be accommodated . furthermore , the steps in the anticipated procedure illustrated in fig1 to 19 may be altered if it is desired to remove the sheath before the dilator is retracted from the vasculature . while several particular forms of the invention have been illustrated and described , it will be apparent that various modifications can be made without departing from the spirit and scope of the invention . for example , references to materials of construction and specific dimensions are also not intended to be limiting in any manner and other materials and dimensions could be substituted and remain within the spirit and scope of the invention . moreover , the introducer of the present invention can be adapted to facilitate the insertion of a myriad of medical devices into vasculature for numerous different uses such as inserting leads in a cardiology application . accordingly , it is not intended that the invention be limited , except as by the appended claims .
a system and method for introducing medical devices within vasculature that incorporates a dual lumen introducer allowing a plurality of guidewires to be introduced without entanglement . the introducer further includes slits formed in the dual lumen introducer and a dilator or an inner member with grooves that facilitate easy removal of the introducer and dilator from vasculature . the dual lumen introducer maintains separation between guidewires . the slits in the dual lumen introducer and the dilator grooves allow removal from the guidewires by slipping the device off the guidewires without retracting them the entire guidewire length . a peel - away sheath protects the vasculature from the guidewires , prevents the dilator from slipping off the guidewires , and maintains access to an expanded vessel for the introduction of medical devices .