Preventing dislodgement of a constricting cord that has been affixed to a cardiac valve annulus
Dislodgment of a constricting cord from an annulus can be prevented by delivering the distal loop portion of the constricting cord to the annulus using a percutaneous delivery tool, and launching anchors into the annulus so as to affix the distal loop portion of the constricting cord to the annulus. The percutaneous delivery tool is withdrawn in a proximal direction after the anchors have been launched. A pushing member is pressed in a distal direction so that the pushing member holds a portion of the constricting cord against the annulus with enough pressure to prevent dislodgment of any of the anchors during the withdrawal of the percutaneous delivery tool.
1. An apparatus for installing a cinching cord onto an annulus or onto tissue adjacent to the annulus, the apparatus comprising:
a housing;
an elongated core mounted with respect to the housing, the core having (a) a distal end, (b) a second channel that runs through the core in a proximal-to-distal direction, and (c) at least one fourth channel that runs through the core in a proximal-to-distal direction;
a cinching cord having a distal loop portion and a proximal portion, wherein the proximal portion of the cinching cord is slidably disposed within the second channel and extends distally beyond the distal end of the core;
at least four support arms mounted to the core that extend distally beyond the distal end of the core;
at least four anchors configured to anchor the distal loop portion of the cinching cord into the annulus or into the tissue adjacent to the annulus;
at least four anchor launchers, wherein each of the anchor launchers is supported by a respective one of the support arms, and wherein each of the anchor launchers is configured to launch a respective one of the anchors into the annulus or into the tissue adjacent to the annulus;
at least one wire that (i) is slidably disposed within the at least one fourth channel, (ii) has a distal end that extends distally beyond the distal end of the core, and (iii) has a proximal end that extends proximally beyond the fourth channel; and
a pushing member affixed to the distal end of the at least one wire such that pushing the proximal end of the at least one wire in a distal direction will push the pushing member in a distal direction,
wherein the cinching cord and the second channel are configured so that after the distal loop portion of the cinching cord is anchored to the annulus or into the tissue adjacent to the annulus by the at least four anchors, progressive movement of the housing in a proximal direction will cause the core to progressively move in a proximal direction with respect to the proximal portion of the cinching cord, and
wherein the pushing member is configured so that after the distal loop portion of the cinching cord is anchored to the annulus or into the tissue adjacent to the annulus by the at least four anchors, pushing the pushing member in a distal direction will hinder dislodgement of the anchors during the movement of the housing in the proximal direction.
2. The apparatus of claim 1 , wherein the distal loop portion of the cinching cord is covered by a sleeve that promotes tissue ingrowth.
3. The apparatus of claim 1 , wherein the pushing member has at least one passage, and wherein the first proximal portion and the second proximal portion of the cinching cord are slidably disposed in the at least one passage.
4. The apparatus of claim 1 , wherein the pushing member has a distal end and a proximal end, and at least one passage that passes through the pushing member in a proximal to distal direction, and wherein the first proximal portion and the second proximal portion of the cinching cord are slidably disposed in the at least one passage.
5. The apparatus of claim 1 , wherein the pushing member comprises a hollow cylinder aligned so that an axial axis of the hollow cylinder is parallel to the at least one wire, and wherein the first proximal portion and the second proximal portion of the cinching cord are slidably disposed within the hollow cylinder.
6. The apparatus of claim 1 , wherein the pushing member is configured so that after the distal loop portion of the cinching cord is anchored to the annulus or into the tissue adjacent to the annulus by the at least four anchors, pushing the pushing member in a distal direction will press the cinching cord against the annulus or the tissue adjacent to the annulus.
7. The apparatus of claim 1 , further comprising at least one crush-resistant channel disposed distally beyond the distal end of the core, wherein the first and second proximal portions of the cinching cord are slidably disposed within the at least one crush-resistant channel.
8. The apparatus of claim 7 , wherein before the distal loop portion of the cinching cord is anchored to the annulus or into the tissue adjacent to the annulus by the at least four anchors, the at least one crush-resistant channel extends to the pushing member.
9. The apparatus of claim 7 , wherein the at least one crush-resistant channel is supported by at least one support arm that is affixed to the core.