Two-piece transseptal cannula, delivery system, and method of delivery

Abstract

A cannula assembly for directing blood from the heart of a patient and a minimally invasive method of implanting the same. The cannula assembly includes a flexible cannula body having a proximal end and a distal end with a receiving portion, and a transseptal tip having a distal end and a proximal end with an engaging portion. First and second anchors are coupled to the transseptal tip and configured to be deployed from a contracted state to an expanded state. The engaging portion of the transseptal tip is operable to removably engage the receiving portion of the flexible cannula body in vivo.

1 . A cannula assembly, comprising:
 a flexible cannula body having distal and proximal ends with a lumen extending therebetween, the distal end including a receiving portion;   a transseptal tip having distal and proximal ends, the proximal end including an engaging portion operable to connect to the receiving portion of the flexible cannula body in vivo; and   first and second anchors coupled to the transseptal tip and configured to be deployed from a contracted state to an expanded state, the first and second anchors configured to engage opposite sides of a heart tissue in the expanded state.   
     
     
         2 . The cannula assembly of  claim 1 , wherein the engaging portion of the transseptal tip has a threaded surface for threadably engaging the receiving portion of the flexible cannula body. 
     
     
         3 . The cannula assembly of  claim 1 , wherein each of the first and second anchors further comprises a plurality of struts extending generally transverse to a lengthwise central axis of the flexible cannula body. 
     
     
         4 . The cannula assembly of  claim 3 , wherein the plurality of struts are formed from a superelastic material and are folded to a position generally parallel with the lengthwise central axis when in the contracted state and extend to a position transverse to the lengthwise central axis when in the expanded state. 
     
     
         5 . The cannula assembly of  claim 4 , wherein the superelastic material is a tubular structure, a wire, or a flat sheet stock. 
     
     
         6 . The cannula assembly of  claim 3 , wherein the plurality of struts of the second anchor further includes a porous polymeric structure. 
     
     
         7 . The cannula assembly of  claim 3 , wherein the plurality of struts of the first anchor further includes a porous polymeric structure. 
     
     
         8 . The cannula assembly of  claim 1 , wherein the receiving portion of the flexible cannula body further includes a seal ring that engages the proximal end of the transseptal tip and forms a fluid-tight seal within the receiving portion. 
     
     
         9 . The cannula assembly of  claim 1 , wherein at least a portion of the flexible cannula body is reinforced with a coil or a braid to increase a torque response of the flexible cannula body. 
     
     
         10 . The cannula assembly of  claim 9 , wherein the distal and proximal ends of the flexible cannula body are not reinforced. 
     
     
         11 . A transseptal tip delivery system in combination with the cannula assembly of  claim 1 , further comprising:
 a delivery catheter having distal and proximal ends and a lumen extending therebetween, the distal end including a receiving portion operable to removably disengage the engaging portion of the transseptal tip in vivo; and   a delivery sheath configured to receive the delivery catheter and the transseptal tip and move relative thereto for deploying the first and second anchors into the expanded state.   
     
     
         12 . The transseptal tip delivery system of  claim 11 , wherein the delivery catheter is configured to move the transseptal tip relative to the delivery sheath. 
     
     
         13 . The transseptal tip delivery system of  claim 11  further comprising:
 a balloon catheter configured to engage an inner surface of the transseptal tip and to resist movement of the transseptal tip from the heart tissue while the receiving portion of the delivery sheath is disengaged from the engaging portion of the transseptal tip.   
     
     
         14 . The transseptal tip delivery system of  claim 11 , wherein the delivery catheter is reinforced with a coil or a braid along at least a portion of its length to increase a torque response of the delivery catheter. 
     
     
         15 . A cannula guide in combination with the cannula assembly of  claim 1 , comprising:
 an expandable member having distal and proximal tapers and an alignment section therebetween; and   a body extending proximally from the expandable member, the expandable member configured to engage an inner surface of the transseptal tip and to resist movement of the transseptal tip from the heart tissue while the receiving portion of the flexible cannula body is connected to the engaging portion of the transseptal tip.   
     
     
         16 . The cannula guide of  claim 15 , wherein the proximal taper is configured to direct the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip. 
     
     
         17 . The cannula guide of  claim 15 , wherein the expandable member includes a distal portion for engaging the inner surface of the transseptal tip and a proximal portion having a diameter that is less than a diameter of the distal portion. 
     
     
         18 . A method of implanting a cannula assembly within a heart tissue, the cannula assembly including a flexible cannula body having distal and proximal ends with a lumen extending therebetween, the distal end including a receiving portion, a transseptal tip having distal and proximal ends, the proximal end including an engaging portion operable to connect to the receiving portion of the flexible cannula body in vivo, and first and second anchors coupled to the transseptal tip, the first and second anchors configured to be deployed from a contracted state to an expanded state and to engage opposite sides of the heart tissue, the method comprising:
 (a) introducing the transseptal tip into the heart tissue;   (b) directing the flexible cannula body to the transseptal tip; and   (c) in vivo connecting the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip.   
     
     
         19 . The method according to  claim 18 , wherein connecting includes threadably engaging the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip. 
     
     
         20 . The method according to  claim 19 , wherein the engaging portion of the transseptal tip includes a threaded surface for threadably engaging the receiving portion of the flexible cannula body. 
     
     
         21 . The method according to  claim 18 , wherein introducing the transseptal tip further comprises:
 directing the transseptal tip to the heart tissue; and   deploying the first and second anchors to engage the opposite sides of the heart tissue in the expanded state.   
     
     
         22 . The method according to  claim 21 , wherein the deploying of the first and second anchors further includes deploying a plurality of struts of the first and second anchors from a position generally parallel with a lengthwise central axis of the flexible cannula body to a position generally transverse to the lengthwise central axis. 
     
     
         23 . The method according to  claim 22 , wherein the plurality of struts are formed from a superelastic material. 
     
     
         24 . The method according to  claim 22 , wherein deploying the plurality of struts further includes deploying a porous polymeric structure to engage at least one side of the heart tissue. 
     
     
         25 . The method according to  claim 18 , wherein directing the transseptal tip further comprises:
 threadably engaging a receiving portion of a delivery catheter to the engaging portion of the transseptal tip; and   advancing the delivery catheter with the transseptal tip to the heart tissue.   
     
     
         26 . The method according to  claim 25  further comprising:
 advancing a delivery sheath through the heart tissue, the delivery sheath including proximal and distal ends and a lumen therebetween;   back-loading the delivery catheter with the transseptal tip through the lumen of the delivery sheath to the heart tissue;   deploying the first anchor by advancing the delivery catheter with the transseptal tip beyond the distal end of the delivery sheath; and   deploying the second anchor by retracting the delivery sheath.   
     
     
         27 . The method according to  claim 26  further comprising:
 disengaging the delivery catheter from the transseptal tip; and   retracting the delivery catheter from the heart tissue.   
     
     
         28 . The method according to  claim 26  further comprising:
 advancing an anchoring guide-element through the delivery catheter and the transseptal tip before deploying the first anchor, the anchoring guide-element including a body portion having a distal end and a proximal end, and an anchoring portion at the distal end of the body portion, wherein the anchoring portion is configured to be deployed from a contracted state generally parallel to a lengthwise central axis of the body portion to an expanded state generally transverse to the lengthwise central axis and is operable to resist retraction through the heart tissue; and   deploying the anchoring portion after deploying the first anchor and before deploying the second anchor.   
     
     
         29 . The method according to  claim 28 , wherein the introducing, directing, and deploying are performed from a primary incision site located substantially near a superficial vein of the lower thorax. 
     
     
         30 . The method according to  claim 29  further comprising:
 creating a secondary incision site substantially near a superficial vein of the upper thorax;   directing a capture device through the secondary incision site to the primary incision site, the capture device operable to redirect the body portion of the anchoring guide-element from the primary incision site to the secondary incision site; and   transferring a proximal end of the body portion of the anchoring guide-element from the primary incision site to the secondary incision site and before directing the flexible cannula body.   
     
     
         31 . The method according to  claim 30 , wherein the superficial vein of the upper thorax is a subclavian vein, a jugular vein, or a junction between a subclavian vein and an adjoining jugular vein and the superficial vein of the lower thorax is a femoral vein. 
     
     
         32 . The method according to  claim 18 , wherein steps (a), (b), and (c) are performed percutaneously with at least one catheter. 
     
     
         33 . The method according to  claim 18 , further comprising:
 directing the transseptal tip to the heart tissue without puncturing a pericardium or a myocardial wall.   
     
     
         34 . The method according to  claim 18 , wherein the introducing, directing, and deploying are performed from a primary incision site located substantially near a superficial vein of the lower thorax. 
     
     
         35 . The method according to  claim 18  further comprising:
 directing a cannula guide to the transseptal tip before directing the flexible cannula body, the cannula guide comprising an expandable member having distal and proximal tapers and an alignment section therebetween and a body extending proximally from the expandable member.   
     
     
         36 . The method according to  claim 35 , wherein the distal taper and at least a portion of the alignment section traverse the lumen of the transseptal tip. 
     
     
         37 . The method according to  claim 35 , wherein the alignment section contacts an inner surface of the transseptal tip. 
     
     
         38 . The method according to  claim 35 , wherein the proximal taper guides the flexible cannula body onto the transseptal tip. 
     
     
         39 . The method according to  claim 35 , wherein the expandable member includes a distal portion and a proximal portion having a diameter that is less than a diameter of the distal portion, wherein the method further comprises:
 inflating the expandable member such that the distal portion engages an inner surface of the transseptal tip.   
     
     
         40 . An introducer assembly for introducing surgical devices into the vascular system, the introducer assembly comprising:
 a removable dilator having an attachment mechanism; and   an introducer including a hub and a sheath extending distally from the hub, the introducer operable to receive the dilator in a movable manner and to maintain a puncture through a vascular wall.   
     
     
         41 . The introducer assembly of  claim 40 , wherein the hub of the introducer further includes a hemostatic seal, a grommet, or an O-ring. 
     
     
         42 . The introducer assembly of  claim 40 , wherein the removable dilator and the introducer are attached together with a frictional fit operable to prevent leakage of blood from the vascular system. 
     
     
         43 . The introducer assembly of  claim 40 , wherein the introducer set includes a sheath introducer, a vascular dilator, and a guide-wire. 
     
     
         44 . A method of introducing a surgical device into the vascular network of a patient with an introducer assembly, the introducer assembly including a removable dilator having an attachment mechanism for removably attaching an introducer set and an introducer including a hub and a sheath extending distally from the hub, the method comprising:
 attaching the introducer set to the attachment mechanism of the removable dilator, the introducer set including a sheath introducer, a vascular dilator, and a guide-wire;   receiving the removable dilator and the introducer set into the introducer;   creating a puncture in a vessel wall of a blood vessel with the guide-wire;   advancing the introducer assembly over the guide-wire and into the blood vessel, thereby dilating the vessel wall until the hub of the introducer contacts an external surface of the blood vessel;   removing the removable dilator and the introducer set; and   directing the surgical device through the introducer and into the blood vessel.   
     
     
         45 . The method according to  claim 44 , wherein the directing of the surgical device further includes opening a hemostatic seal within the hub of the introducer. 
     
     
         46 . The method according to  claim 44  further comprising:
 sealing a proximal end of the hub of the introducer after removing the removable dilator.   
     
     
         47 . A method of in vivo coupling a flexible cannula body to a transseptal tip, the flexible cannula body having distal and proximal ends with a lumen extending therebetweeen, the distal end including a receiving portion having a first marker, and the transseptal tip having distal and proximal ends, the proximal end including an engaging portion having a second marker, the method comprising:
 directing the flexible cannula body to the transseptal tip;   in vivo localizing the first and second markers;   coupling the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip; and   continuing the coupling until the first marker overlays the second marker.   
     
     
         48 . The method of in vivo coupling according to  claim 47 , wherein the coupling includes threadably engaging the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip. 
     
     
         49 . The method of in vivo coupling according to  claim 47 , wherein the coupling includes magnetically attaching the receiving portion of the flexible cannula body to the engaging portion of the transseptal tip. 
     
     
         50 . A method of aligning a flexible cannula body to a transseptal tip, in vivo, the flexible cannula body having distal and proximal ends with a lumen extending therebetween, the distal end including a receiving portion, and the transseptal tip having distal and proximal ends, the proximal end including an engaging portion, the method comprising:
 directing a cannula guide to the transseptal tip, the cannula guide comprising an expandable member having distal and proximal tapers and an alignment section therebetween and a body extending proximally from the expandable member, the alignment section configured to engage an inner surface of the transseptal tip and to resist movement of the transseptal tip;   inflating the expandable member such that the expandable member engages the inner surface of the transseptal tip; and   advancing the flexible cannula body over the proximal taper to the engaging portion of the transseptal tip.   
     
     
         51 . The method according to  claim 50 , wherein the inflating includes inflating distal and proximal portions of the expandable member such that the distal portion engages the inner surface of the transseptal tip and the proximal portion is inflated to a diameter that is less than a diameter of the distal portion. 
     
     
         52 . A stepped balloon for in vivo alignment of a cannula to a trans-tissue device, the stepped balloon comprising:
 an expandable member having distal and proximal tapers and an alignment section therebetween, the alignment section having a distal portion and a proximal portion that is expandable to a diameter that is less than a diameter of the distal portion, the alignment section configured to engage an inner surface of the trans-tissue device; and   a body extending proximally from the expandable member.   
     
     
         53 . A method of removing a circulatory assist device, the circulatory assist device including a transseptal tip, a pump, and a flexible cannula body extending proximally from the transseptal tip to the pump, the method comprising:
 disengaging the flexible cannula body from the pump;   uncoupling the flexible cannula body from the transseptal tip;   retracting the flexible cannula body; and   sealing the transseptal tip.   
     
     
         54 . The method according to  claim 53  further comprising:
 advancing a cannula guide to the transseptal tip before uncoupling the flexible cannula body from the transseptal tip, the cannula guide comprising an expandable member having distal and proximal tapers and an alignment section therebetween and a body extending proximally from the expandable member, the alignment section configured to engage an inner surface of the transseptal tip.   
     
     
         55 . The method according to  claim 53 , wherein the sealing further includes directing a closure device to the transseptal tip and deploying the closure device to seal a lumen of the transseptal tip. 
     
     
         56 . The method according to  claim 55 , wherein the closure device is an atrial septal defect closure device.