It is claimed:
1. An endovascular stent for placement at a vascular injury site, for inhibiting restenosis at the site, comprising
a body formed of one or more filaments,
carried on the one or more filaments, a bioerodable drug-release coating having a thickness of between 3-20 microns, and composed of (i) 20-60 weight percent of a biodegradable polymer substrate and (ii) 40-80 weight percent of an anti-restenosis compound, and
a polymer undercoat disposed between the stent-body filaments and said coating,
said stent being expandable from a contracted condition in which the stent can be delivered to a vascular injury site via a catheter, and an expanded condition in which the stent coating can be placed in contact with the vessel at the injury site,
said coating being effective to release an amount of the compound to inhibit restenosis at the site.
2. The stent of claim 1, wherein said biodegradable polymer substrate is comprised of a polymer selected from the group consisting of poly-l-lactic acid, poly-d-lactic acid, poly-dl-lactic acid, and copolymers thereof.
3. The stent of claim 1, wherein the filaments in the body are formed of metal.
4. The stent of claim 1, wherein the filaments in the body are formed of a biodegradable polymer.
5. The stent of claim 1, wherein the underlayer has a thickness of between 1-5 microns.
6. The stent of claim 1, wherein said anti-restenosis compound is a macrocyclic triene compound.
7. The stent of claim 6, wherein the stent body is a metal-filament structure, the undercoat is formed of a parylene polymer and has a thickness between 1 and 5 microns, and the coating has a thickness between 2 and 15 microns.
8. The stent of claim 7, wherein said compound is present in the coating in an amount between 50% and 75% by weight.
9. The stent of claim 6, wherein said compound has the form
6
where (i) R is H or CH2XOH, and X is a linear or branched alkyl group containing 1 to 5 carbon atoms, when R is H (R is at the 28 position O) or (ii) at least one of R and R have the form
7
where m is an integer from 1 to 3 and R1 and R2 are each a hydrogen, or an alkyl radical having from one to three carbon atoms, or, alternatively, wherein R1 and R2 together with a nitrogen atom to which they are attached form a saturated heterocyclic ring having four carbon atoms. 10.
10. The stent of claim 9, where R is H and X is CH2.
11. The stent of claim 1, wherein said coating further includes a bioactive agent selected from the group consisting of antiplatelet agents, fibrinolytic agents, and thrombolytic agents.
12. An endovascular stent for placement at a vascular injury site, for inhibiting restenosis at the site, comprising
a body having an open-lattice structure formed of linked filaments, and
carried on the stent-body filaments, a drug-release coating having a thickness of between 3-30 microns, said coating containing a mixture of polymer and a macrocyclic triene anti-restenosis agent, wherein said agent is present in a agent-to-polymer ratio of greater than 50% by weight and wherein said coating is attached to said filament using a polymer underlayer.
13. The stent of claim 12, wherein said underlayer has a thickness of between 1-5 microns.
14. The stent of claim 12, wherein said polymer substrate is comprised of a polymer selected from the group consisting of poly-l-lactic acid, poly-d-lactic acid, poly-dl-lactic acid, and copolymers thereof.
15. The stent of claim 12, wherein the filaments in the body are formed of metal.
16. The stent of claim 12, wherein the filaments in the body are formed of a biodegradable polymer.
17. The stent of claim 12, wherein the underlayer is formed of parylene.
18. A method for inhibiting restenosis at a vascular injury site, comprising
delivering to the vascular injury site, an endovascular stent comprising
(a) a body formed of one or more filaments,
(b) carried on the one or more filament(s), a bioerodable drug-release coating having a thickness of between 3-20 microns, and composed of (i) 20 and 60 weight percent of a biodegradable polymer substrate and (ii) 40-80 weight percent of an anti-restenosis compound, and
(c) a polymer undercoat disposed between the stent-body filaments and said coating, and
expanding the stent at the vascular injury site, to bring the stent coating in contact with the vessel at the injury site,
wherein said coating is effective to release an amount of the compound to inhibit restenosis at the site.
19. The method of claim 18, wherein said biodegradable polymer substrate is comprised of a polymer selected from the group consisting of poly-l-lactic acid, poly-d-lactic acid, poly-dl-lactic acid, and copolymers thereof.
20. The method of claim 18, wherein said underlayer has a thickness of between 1-5 microns.
21. The method of claim 18, wherein the filaments in the body are formed of metal.
22. The method of claim 18, wherein the filaments in the body are formed of a biodegradable polymer.
23. The method of claim 18, wherein the underlayer is formed of parylene.
24. The method of claim 18, wherein the stent body is a metal-filament structure, the undercoat is formed of a parylene polymer having a thickness between 1 and 5 microns, and the coating has a thickness between 2 and 15 microns.
25. The method of claim 24, wherein said compound is present in the coating in an amount between 50% and 75% by weight.
26. The method of claim 18, wherein the anti-restenosis compound is macrocyclic triene immunosuppressive compound.
27. The method of claim 26, wherein said compound has the form
8
where (i) R is H or CH2XOH, and X is a linear or branched alkyl group containing 1 to 5 carbon atoms, when R is H (R is at the 28 position O) or (ii) at least one of R and R have the form
9
where m is an integer from 1 to 3 and R1 and R2 are each a hydrogen, or an alkyl radical having from one to three carbon atoms, or, alternatively, wherein R1 and R2 together with a nitrogen atom to which they are attached form a saturated heterocyclic ring having four carbon atoms.
28. The method of claim 27, where R is H and X is CH2.
29. The method of claim 26, for use where the vascular injury is produced during an angiographic procedure in which a vessel region is overstretched at least 30% in diameter.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A high-frequency power supply device including an oscillator to output a high-frequency signal, an amplifier to amplify the output of the oscillator for supplying a high-frequency output to a load, and a direct-current power supply to supply a direct-current power voltage to the amplifier, the high-frequency power supply device comprising:
a direct-current output detector connected between the direct-current power supply and the amplifier to detect at least the direct-current power voltage supplied from the direct-current power supply to the amplifier;
a high-frequency output detector connected between the amplifier and the load to detect the high-frequency output supplied from the amplifier to the load;
a loss calculator that calculates a loss generated in the amplifier;
a first controller which, when the calculated loss by the loss calculator exceeds a loss set value determined beforehand, causes the direct-current power supply to lower the direct-current power voltage supplied to the amplifier from the direct-current power supply until the calculated loss becomes equal to the loss set value, the first controller further causing, when the calculated loss is no greater than the loss set value, the direct-current power supply to maintain the direct-current power voltage supplied to the amplifier from the direct-current power supply at an appropriate direct-current voltage set value; and
a second controller which controls the output of the oscillator or the amplifier so that the high-frequency output supplied to the load from the amplifier approaches a high-frequency output set value.
2. The high-frequency power supply device according to claim 1, wherein the loss set value is set to be no greater than a permissible maximum loss generated in the amplifier when heat generated in the amplifier reaches an upper limit of a permissible range.
3. The high-frequency power supply device according to claim 1, wherein the loss calculator calculates loss that is generated in a semiconductor element constituting the amplifier.
4. The high-frequency power supply device according to claim 3, wherein the loss set value is set to be no greater than a permissible maximum loss generated in the semiconductor element constituting the amplifier when heat generated in the semiconductor element reaches an upper limit of a permissible range.
5. The high-frequency power supply device according to claim 1, wherein the first controller causes, when the calculated loss by the loss calculator exceeds a first loss set value determined beforehand, the output voltage of the direct-current power supply to be lowered within a range that does not fall below a predetermined lower limit value in order to make the calculated loss equal to the first loss set value, the first controller further causing, when the calculated loss is no greater than the first loss set value, the direct-current power voltage supplied to the amplifier from the direct-current power supply to be maintained at an appropriate direct-current voltage set value,
wherein the second controller controls, when the direct-current power voltage is greater than the lower limit value, the output of the oscillator or the amplifier so that the high-frequency output supplied to the load from the amplifier approaches a high-frequency output set value, the second controller further controlling, when the direct-current power voltage is no greater than the lower limit value, the output of the oscillator or the amplifier in order to make the calculated loss equal to the first loss set value or to a second loss set value which is slightly greater than the first loss set value.
6. The high-frequency power supply device according to claim 5, wherein the first loss set value and the second loss set value are no greater than a permissible maximum loss generated in the amplifier when heat generated in the amplifier reaches an upper limit of a permissible range.
7. The high-frequency power supply device according to claim 5, wherein the loss calculator calculates loss generated in a semiconductor element constituting the amplifier.
8. The high-frequency power supply device according to claim 7, wherein the first loss set value and the second loss set value are no greater than a permissible maximum loss generated in the semiconductor element constituting the amplifier when heat generated in the semiconductor element reaches an upper limit of a permissible range.
9. A high-frequency power supply device including an oscillator to output a high-frequency signal, an amplifier to amplify an output of the oscillator for supplying a high-frequency output to a load, and a direct-current power supply to supply a direct-current power voltage to the amplifier, the high-frequency power supply device comprising:
a junction temperature calculator that calculates junction temperature of a semiconductor amplifier element provided in the amplifier;
a first controller which causes, when the calculated junction temperature by the junction temperature calculator exceeds a junction temperature set value determined beforehand, the direct-current power supply to lower the direct-current power voltage supplied to the amplifier from the direct-current power supply until the calculated junction temperature becomes equal to the junction temperature set value, the first controller further causing, when the calculated junction temperature is no greater than the junction temperature set value, the direct-current power supply to maintain the direct-current power voltage supplied to the amplifier from the direct-current power supply at an appropriate direct-current voltage set value; and
a second controller which controls the output of the oscillator or the amplifier so that the high-frequency output supplied to the load from the amplifier approaches a high-frequency output set value.
10. The high-frequency power supply device according to claim 9, wherein the junction temperature set value is set to be no greater than a permissible maximum value of the junction temperature of the semiconductor amplifier element.
11. The high-frequency power supply device according to claim 9, wherein the first controller causes, when the calculated junction temperature by the junction temperature calculator exceeds a first junction temperature set value determined beforehand, the output voltage of the direct-current power supply to be lowered within a range that does not fall below a predetermined lower limit value in order to make the calculated junction temperature equal to the first junction temperature set value, the first controller further causing, when the calculated junction temperature is no greater than the first junction temperature set value, the direct-current power voltage supplied to the amplifier from the direct-current power supply to be maintained at an appropriate direct-current voltage set value,
wherein the second controller controls, when the direct-current power voltage is greater than the lower limit value, the output of the oscillator or the amplifier so that the high-frequency output supplied to the load from the amplifier approaches a high-frequency output set value, the second controller further controlling, when the direct-current power voltage is no greater than the lower limit value, the output of the oscillator or the amplifier in order to make the calculated junction temperature equal to the first junction temperature set value or to a second junction temperature set value which is slightly higher than the first junction temperature set value.
12. The high-frequency power supply device according to claim 11, wherein the first junction temperature set value and the second junction temperature set value are set to be no greater than the permissible maximum value of the junction temperature of the semiconductor amplifier element.
13. The high-frequency power supply device according to claim 1, wherein the direct-current voltage set value is set at a value that maximizes efficiency of the amplifier within a range that causes no distortion of a waveform of the high-frequency output.
14. The high-frequency power supply device according to claim 9, wherein the direct-current voltage set value is set at a value that maximizes efficiency of the amplifier within a range that causes no distortion of a waveform of the high-frequency output.
15. A high-frequency power supply device including an oscillator to output a high-frequency signal, an amplifier to amplify an output of the oscillator for supplying a high-frequency output to a load, and a direct-current power supply to supply a direct-current power voltage to the amplifier, the high-frequency power supply device comprising:
a direct-current output detector connected between the direct-current power supply and the amplifier to detect at least the direct-current power voltage supplied from the direct-current power supply to the amplifier;
a high-frequency output detector connected between the amplifier and the load to detect the high-frequency output supplied from the amplifier to the load;
a junction temperature calculator that calculates junction temperature of a semiconductor amplifier element provided in the amplifier;
a first controller which causes, when the calculated junction temperature by the junction temperature calculator exceeds a junction temperature set value determined beforehand, the direct-current power supply to lower the direct-current power voltage supplied to the amplifier from the direct-current power supply until the calculated junction temperature becomes equal to the junction temperature set value, the first controller further causing, when the calculated junction temperature is no greater than the junction temperature set value, the direct-current power supply to maintain the direct-current power voltage supplied to the amplifier from the direct-current power supply at an appropriate direct-current voltage set value; and
a second controller connected to the high-frequency output detector and the amplifier to control the output of the oscillator or the amplifier so that the high-frequency output supplied to the load from the amplifier approaches a high-frequency output supplied to the load from the amplifier approaches a high-frequency output set value.