Radial and trans-endocardial delivery catheter
A needle-injection catheter includes a catheter body having a distal end, a proximal end, a stiff proximal portion, a flexible distal portion, and a delivery lumen extending therethrough. In a first embodiment, a straight injection needle extends coaxially from a distal tip of the flexible portion of the catheter body, and a plurality of penetration limiting elements positioned circumferentially about a base of the straight injection needle and configured to fold radially inwardly against a shaft of the needle when constrained in a tubular lumen and to extend radially outwardly when unconstrained. In a second embodiment, a helical needle extends from the distal tip of the flexible portion of the catheter body. The helical needle has at least one helical delivery lumen connected to receive an injectable substance from the delivery lumen of the catheter body.
1. A method for introducing a needle injection catheter into a heart chamber from a radial artery, said method comprising:
advancing a guide catheter through the radial artery and into the heart chamber;
positioning the guide catheter to align a distal tip of the guide catheter with a target location on an endocardial wall of the heart chamber;
advancing the needle-injection catheter through a lumen of the guide catheter so that a straight needle projecting coaxially emerges from a distal tip of the needle injection catheter and penetrates the endocardial wall to position an injection port at the tip of the needle in the myocardium, wherein a plurality of penetration limiting elements remain constrained within the guide catheter until the needle emerges from the distal tip at which point the elements self-deploy radially outwardly from a base of the needle to limit the penetration of the needle into the myocardium in order to reduce the risk of perforation of the endocardial wall.
2. A method as in claim 1 , wherein positioning comprises rotating and/or axially translating a guide catheter having a pre-shaped deflection at its distal end.
3. A method as in claim 1 , wherein positioning comprises deflecting the distal tip of the guide catheter while the guide catheter is in the heart chamber.
4. A method as in claim 1 , wherein advancing the needle-injection catheter comprises constraining the penetration limiting elements in an introducer sleeve, engaging a distal end of the sleeve against a proximal hub of the guide catheter, and advancing a distal end of the needle-injection catheter into a proximal portion of the guide catheter while the penetration limiting elements remain constrained.
5. A method as in claim 1 , wherein the penetration limiting elements comprise resilient petals which have bases attached to the catheter body at the base of the straight needle.
6. A method as in claim 5 , wherein the petals are shaped to curve outwardly from the catheter body when unconstrained.
7. A method as in claim 6 ; wherein the petals are wire loops folded in a continuous length of a shape memory wire.
8. A method as in claim 7 , wherein a platinum wire is wound over the shape memory wire to provide radiopacity.
9. A method as in claim 6 , wherein the petals are solid leaves which overlap when folded inwardly against the needle shaft.
10. A method as in claim 5 , wherein the catheter includes from two to six petals.
11. A needle-injection catheter comprising:
a catheter body having a distal end, a proximal end, a stiff proximal portion, a flexible distal portion, and a delivery lumen extending therethrough;
a straight injection needle extending coaxially from a distal tip of the flexible portion of the catheter body; and
a plurality of penetration limiting elements positioned circumferentially about a base of the straight injection needle and configured to fold radially inwardly against a shaft of the needle when constrained in a tubular lumen and to extend radially outwardly when unconstrained.
12. A catheter as in claim 11 , wherein the penetration limiting elements comprise resilient petals which have bases attached to the catheter body at the base of the straight needle.
13. A catheter as in claim 12 , wherein the catheter includes from two to six petals.
14. A catheter as in claim 12 , wherein the petals are shaped to curve outwardly from the catheter body when unconstrained.
15. A catheter as in claim 14 , wherein the petals are wire loops folded in a continuous length of a shape memory wire.
16. A catheter as in claim 15 , wherein a platinum wire is wound over the shape memory wire to provide radiopacity.
17. A catheter as in claim 14 , wherein the petals are solid leaves which overlap when folded inwardly against the needle shaft.
18. A catheter as in claim 11 , wherein the stiff proximal portion of the catheter body comprises a braided polymeric tube and the flexible distal portion of the catheter body comprises a helical metal coil.
19. A catheter as in claim 11 , wherein the catheter body has a first lumen for delivering an injectable composition to the needle and a second lumen for delivery of a contrast agent to the base of the needle.
20. A catheter as in claim 11 , further comprising a handle on the proximal end of the catheter body.
21. A catheter as in claim 11 , wherein the catheter body is configured to be delivered through a 6.5 Fr guide catheter.