Stent with expandable foam
A stent for treating a physical anomaly. The stent includes a skeletal support structure for expanding in the physical anomaly and a shape memory material coupled to the skeletal support structure.
1. A system comprising:
a first shape memory polymer (SMP), the first SMP including a first SMP foam;
a second SMP, the second SMP including a second SMP foam;
a third SMP;
wherein the first SMP foam: (a)(i) is an open cell foam, (a)(ii) is biodegradable, (a)(iii) includes a first channel, and (a)(iv) includes a reaction product of at least two of Hexamethylene diisocyanate (HDI), triethanolamine (TEA), hydroxypropyl ethylenediamine (HPED), or combinations thereof;
wherein the second SMP foam: (b)(i) is cylindrical, (b)(ii) includes a second channel, and (b)(iii) is included in the first channel; and
wherein: (c)(i) the first SMP foam is in a first state; and (c)(ii) the first SMP foam is configured to expand to a second state, radially outward from the second SMP foam, in response to thermal stimulus;
wherein: (d)(i) the third SMP is between the first and second SMP foams; (d)(ii) the third SMP includes a stent having a first strut that includes the third SMP and a second strut that includes the third SMP;
wherein the first SMP is coupled to a wire, the second SMP is coupled to the wire, and the third SMP is coupled to the wire.
2. The system of claim 1 wherein:
the first SMP foam has a glass transition temperature (Tg) between 30° C. and 86° C.; and
the first SMP foam is cross-linked.
3. The system of claim 1 wherein the first SMP foam is a first thermoset SMP foam and the second SMP foam is a second thermoset SMP foam.
4. A system comprising:
a first shape memory polymer (SMP), the first SMP including a SMP foam;
a second SMP;
wherein the SMP foam: (a)(i) is an open cell foam, (a)(ii) is biodegradable, (a)(iii) includes a first channel, and (a)(iv) includes a reaction product of at least two of a diisocyanate, triethanolamine (TEA), hydroxypropyl ethylenediamine (HPED), or combinations thereof;
wherein the second SMP: (b)(i) is a cylindrical stent having a first strut that includes the second SMP and a second strut that includes the second SMP, (b)(ii) includes a second channel, and (b)(iii) is included in the first channel;
wherein: (c)(i) the SMP foam is in a first state; and (c)(ii) the SMP foam is configured to expand to a second state, radially outward from the second SMP, in response to thermal stimulus;
wherein the SMP foam adheres to the second SMP via a polyurethane-based adhesive;
wherein the first SMP is crimped and the second SMP is crimped;
wherein the SMP foam is cross-linked;
wherein the SMP foam has a glass transition temperature (Tg) between 30° C. and 86° C.;
wherein the first SMP is coupled to a wire and the second SMP is coupled to the wire;
wherein the SMP foam is a thermoset polyurethane polymer;
wherein the SMP foam is configured to have hysteresis corresponding to the Tg.
5. The system of claim 4 wherein:
the SMP foam is a reaction product of the diisocyanate;
the diisocyanate includes Hexamethylene diisocyanate (HDI).
6. The system of claim 5 wherein the SMP foam is a reaction product of the TEA and the HPED.
7. The system of claim 5 wherein the wire is configured to guide the first and second SMPs within a vascular system and to a physiological void.
8. The system of claim 7 wherein the polyurethane-based adhesive is a thermoset polymer.
9. The system of claim 8 wherein the SMP foam is configured to have, in the second state, a volumetric void fraction greater than 98% and less than 100%.
10. The system of claim 8 wherein the SMP foam is configured to have the hysteresis corresponding to the Tg in response to absorption of physiological compounds that act as plasticizers.
11. The system of claim 4 wherein the SMP foam is a reaction product of the diisocyanate, the TEA, and the HPED.
12. A system comprising:
a first shape memory polymer (SMP), the first SMP including a SMP foam;
a second SMP;
wherein the SMP foam: (a)(i) is an open cell foam, (a)(ii) is biodegradable, (a)(iii) includes a first channel, and (a)(iv) includes a reaction product of a diisocyanate, triethanolamine (TEA), and hydroxypropyl ethylenediamine (HPED);
wherein the second SMP: (b)(i) is a cylindrical stent having a first strut that includes the second SMP and a second strut that includes the second SMP, (b)(ii) includes a second channel, and (b)(iii) is included in the first channel;
wherein: (c)(i) the SMP foam is in a first state; and (c)(ii) the SMP foam is configured to expand to a second state, radially outward from the second SMP, in response to thermal stimulus;
wherein the first SMP is crimped and the second SMP is crimped;
wherein the SMP foam has a glass transition temperature (Tg) between 30° C. and 86° C.;
wherein the SMP foam is a thermoset polyurethane polymer;
wherein the first SMP is coupled to a wire and the second SMP is coupled to the wire.
13. The system of claim 12 wherein the SMP foam:
adheres to the second SMP via a polyurethane-based adhesive;
is configured to have hysteresis corresponding to the Tg.