Temporary interatrial shunts
Described embodiments include apparatus ( 28 ) that includes a shunt ( 26 ). The shunt includes a flared distal portion ( 40 ), a flared proximal portion ( 44 ), and an intermediate portion ( 42 ), disposed between the distal portion and the proximal portion. The apparatus further includes a constricting flexible longitudinal element ( 38 ) passing circumferentially along the intermediate portion of the shunt, configured to constrict the intermediate portion of the shunt, and one or more proximal-portion-collapsing flexible longitudinal elements ( 36 ) configured to collapse the proximal portion of the shunt. Other embodiments are also described.
1. An apparatus configured to be positioned across an aperture in an atrial septum of a subject, the apparatus comprising:
a catheter;
a shunt, comprising:
a flared distal portion;
a flared proximal portion, the flared distal and proximal portions each configured to transition between a collapsed delivery state and an expanded deployed state; and
an intermediate portion disposed between the flared distal portion and the flared proximal portion, the intermediate portion configured to be positioned in the aperture in the atrial septum, the shunt defining a passageway for blood to flow across the atrial septum through the shunt; and
one or more retrieval elements extending from the shunt to the catheter for collapsing the flared proximal portion of the shunt from the expanded deployed state to the collapsed delivery state, the one or more retrieval elements configured to remain coupled to the shunt throughout the time the shunt is placed inside the subject.
2. The apparatus according to claim 1 , wherein the one or more retrieval elements comprise a constricting flexible longitudinal element passing circumferentially along the intermediate portion of the shunt, configured to constrict the intermediate portion of the shunt.
3. The apparatus according to claim 2 , wherein the constricting flexible longitudinal element comprises a wire and the intermediate portion of the shunt is shaped to define a plurality of orifices, and wherein the wire passes circumferentially along the intermediate portion by passing through the orifices.
4. The apparatus according to claim 1 , wherein the flared proximal portion of the shunt is shaped to define a plurality of orifices, and wherein the one or more retrieval elements comprise one or more proximal-portion-collapsing flexible longitudinal elements comprising one or more wires, each of which passes through at least two of the orifices.
5. The apparatus according to claim 1 , further comprising:
a sheath having a distal end, the shunt being configured to open from the collapsed delivery state to the expanded deployed state upon deployment from the sheath.
6. The apparatus according to claim 5 , wherein the shunt and the one or more retrieval elements comprise a plurality of wires, distal ends of which are joined together, and proximal ends of which are coupled to the sheath.
7. The apparatus according to claim 6 , wherein the shunt is configured to open by the wires expanding radially outward from each other.
8. The apparatus according to claim 5 , further comprising:
a guidewire; and
a stopper coupled to a distal portion of the guidewire, the stopper configured to apply a longitudinally compressive force to the shunt by pressing against the flared distal portion of the shunt when the sheath and the shunt are over the guidewire.
9. The apparatus according to claim 8 , wherein the shunt is shaped to define a distal aperture configured to fittingly receive the stopper.
10. The apparatus according to claim 8 , wherein the stopper comprises a bead.
11. The apparatus according to claim 1 , wherein, in the expanded deployed state, the flared proximal portion of the shunt and the flared distal portion of the shunt are wider than the intermediate portion of the shunt.
12. The apparatus according to claim 1 , further comprising a guide comprising a bead coupled to a distal portion of the guide for collapsing the shunt.