Systems and methods for delivering stent grafts
A delivery catheter comprises an inner shaft and an outer sheath. A stent-graft is held on a region of the inner shaft. An enlarged diameter distal region of the outer sheath constrains the stent-graft. Its retraction allows the stent-graft to deploy. A finger wheel on a handle is used to retract the outer sheath and is coupled to a sliding block with cable(s). The sliding block is coupled to the outer sheath and is held within a sliding track. The wheel can be actuated to tension the cable(s) and deform latch(es) coupled to sliding block, freeing them from slot(s) in the sliding track and allowing retraction of the sliding block and the outer sheath. A reinforcement sleeve is coupled to a smaller diameter proximal region of the outer sheath. A gap between the outer sheath distal region and the reinforcement sleeve allows the distal outer shaft region to be retracted.
1 . A catheter apparatus for delivering an implant, the catheter apparatus comprising: an inner shaft having a proximal portion, a distal portion, and an implant holding region at the distal portion;
an outer sheath disposed at least over the implant holding region of the inner shaft, the outer sheath being configured to be proximally retracted to expose an implant placed in the implant holding region to allow the implant to be deployed, and the retractable outer sheath having a proximal end and a distal end;
at least one retractable latch coupled to the proximal end of the outer sheath and configured to resist retraction of the outer sheath; and
at least one cable coupled to the at least one retractable latch,
wherein the at least one retractable latch is biased against at least one slot and is configured to be released upon tensioning of the at least one cable over a threshold force so that the proximal retraction of the at least one cable over the threshold force proximally retracts the at least one retractable latch and the outer sheath.
2 . The catheter apparatus of claim 1 , further comprising a handle body enclosing the proximal portion of the inner shaft and the proximal end of the outer sheath.
3 . The catheter apparatus of claim 2 , wherein the handle body comprises an inner track, wherein the at least one retractable latch is configured to releasably couple to the inner track of the handle body to resist proximal retraction, and wherein the tensioning of the at least one cable over the threshold force releases the at least one retractable latch from the inner track of the handle body.
4 . The catheter apparatus of claim 3 , wherein the at least one retractable latch is biased to push outwardly against the inner track of the handle body to provide friction to resist proximal retraction, and wherein the tensioning of the at least one cable over the threshold force changes a configuration of the at least one retractable latch to release from the inner track of the handle body.
5 . The catheter apparatus of claim 3 , wherein the at least one retractable latch is biased to push outwardly into the at least one slot to resist proximal retraction, and wherein the tensioning of the at least one cable over the threshold force retracts the at least one retractable latch from the at least one slot thereby allowing proximal retraction of the outer sheath.
6 . The catheter apparatus of claim 5 , wherein the at least one slot comprises a plurality of slots.
7 . The catheter apparatus of claim 3 , further comprising a sliding block coupling the proximal end of the outer sheath to the at least one retractable latch, wherein the sliding block is configured to slide along the inner track of the handle body.
8 . The catheter apparatus of claim 2 , further comprising a pulley operatively coupled to the at least one cable, wherein the pulley is configured to be actuated to proximally retract the at least one cable, and wherein a spool is housed within the handle body.
9 . The catheter apparatus of claim 8 , wherein the pulley comprises a rotatable spool.
10 . The catheter apparatus of claim 9 , further comprising a finger wheel coupled to handle body and the rotatable spool, wherein the finger wheel is configured to be spun to actuate the pulley.