초록 ▼

A medical device (10) includes a catheter shaft (11) including inner and outer catheter shafts (12 and 14), and an expandable balloon (18) carried by the catheter shaft (11). The balloon (18) is made from an irradiation cross-linked mixture of a polyamide elastomer and at least one additional cross-

A medical device (10) includes a catheter shaft (11) including inner and outer catheter shafts (12 and 14), and an expandable balloon (18) carried by the catheter shaft (11). The balloon (18) is made from an irradiation cross-linked mixture of a polyamide elastomer and at least one additional cross-linking reactant. The polyamide elastomer can be a polyester amide, a polyether ester amide or a polyether amide, and is preferably a nylon block copolymer. The cross-linking reactant can be: (a) a difunctional material, (b) a trifunctional material, (c) a tetrafunctional material, or (d) an aromatic molecule containing at least two ring substituents, each of the ring substituents having labile hydrogens at a benzylic site therein. The cross-linking reactant can also be diallyl phthalate or meta-phenylene dimaleimide. Irradiation is carried out by exposure to an electron beam or to ultraviolet, X- or gamma radiation, preferably at a total fluence of about 0.5 to about 20 megarads. The amount of the cross-linking reactant is selected to avoid the formation of gelling during the process by which the balloon (18) is made, and the amount of the cross-linking agent and the irradiation fluence are selected to give the balloon a strength generally about equal to that which would be obtained by mere irradiation.

대표청구항 ▼

A medical device (10) includes a catheter shaft (11) including inner and outer catheter shafts (12 and 14), and an expandable balloon (18) carried by the catheter shaft (11). The balloon (18) is made from an irradiation cross-linked mixture of a polyamide elastomer and at least one additional cross-

A medical device (10) includes a catheter shaft (11) including inner and outer catheter shafts (12 and 14), and an expandable balloon (18) carried by the catheter shaft (11). The balloon (18) is made from an irradiation cross-linked mixture of a polyamide elastomer and at least one additional cross-linking reactant. The polyamide elastomer can be a polyester amide, a polyether ester amide or a polyether amide, and is preferably a nylon block copolymer. The cross-linking reactant can be: (a) a difunctional material, (b) a trifunctional material, (c) a tetrafunctional material, or (d) an aromatic molecule containing at least two ring substituents, each of the ring substituents having labile hydrogens at a benzylic site therein. The cross-linking reactant can also be diallyl phthalate or meta-phenylene dimaleimide. Irradiation is carried out by exposure to an electron beam or to ultraviolet, X- or gamma radiation, preferably at a total fluence of about 0.5 to about 20 megarads. The amount of the cross-linking reactant is selected to avoid the formation of gelling during the process by which the balloon (18) is made, and the amount of the cross-linking agent and the irradiation fluence are selected to give the balloon a strength generally about equal to that which would be obtained by mere irradiation. controller which determines positions of the plurality of transponders in response to the reply signals and from those positions produces a value indicating cardiac performance. 11. The apparatus as recited in claim 10 wherein each transponder is formed on a stent adapted to be implanted in a blood vessel of the heart. 12. The apparatus as recited in claim 10 wherein the controller determines movement of the heart from changes in positions of the plurality of transponders. 13. The apparatus as recited in claim 10 wherein the controller derives a value for the volume of the heart from the positions of the plurality of transponders. 14. The apparatus as recited in claim 13 wherein the controller determines cardiac output from changes in the volume of the heart. 15. The apparatus as recited in claim 10 wherein at least one of the plurality of transponders has a sensor that detects a physical characteristic of the animal and transmits information regarding the physical characteristic via the reply signal. 16. The apparatus as recited in claim 15 wherein the at least one of the plurality of transponders is formed on a stent adapted to be implanted in a blood vessel and the sensor provides information regarding a pressure drop across the stent. 17. The apparatus as recited in claim 15 wherein the sensor provides information regarding electrical activity of the heart. 18. A method for monitoring activity of an organ in an animal, that method comprising: attaching at least one transponder to the organ; interrogating the transponder with a wirelessly transmitted interrogation signal; the transponder reacting to the interrogation signal by wirelessly transmitting a reply signal; receiving the reply signal from the transponder; and processing the reply signal to derive information regarding the activity of the organ. 19. The apparatus as recited in claim 18 wherein processing the reply signal derives information regarding movement of the organ. 20. The apparatus as recited in claim 18 wherein processing the reply signal derives information regarding changes in volume of the organ. 21. The apparatus as recited in claim 18 further comprising sensing a physical characteristic of the organ; transmitting information about that physical characteristic with the reply signal; and wherein processing the reply signal obtain the information about that physical characteristic.