초록 ▼

A medical device which comprises a shape memory alloy (SMA) portion which is deformable from an undeformed first configuration assumed by it in an austenitic state of the SMA to a deformed second configuration, whereby the SMA is converted into a strain-induced martensite or partial martensite. This

A medical device which comprises a shape memory alloy (SMA) portion which is deformable from an undeformed first configuration assumed by it in an austenitic state of the SMA to a deformed second configuration, whereby the SMA is converted into a strain-induced martensite or partial martensite. This conversion increases the temperature of transformation (A.sub.s) from an initial transformation temperature A.sub.s .degree. to a temperature A.sub.s '. When the SMA, once in the second configuration, is heated to a temperature higher than A.sub.s ', it transforms to an at least partial austenite and it transforms towards the undeformed first configuration with a decrease of A.sub.s from A.sub.s ' to A.sub.s .degree.. A.sub.s .degree. is below body temperature such that when the device is deployed in the body, after placing it in its target location with the SMA portion in the second configuration and then heating it to assume its first configuration, the SMA is stable in the at least partial austenite at body temperature.

대표청구항 ▼

[ We claim:] [1.] A medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states, the SMA being transformable from a martensitic to an austenitic state by an austenitic transformation occurring in a t

[ We claim:] [1.] A medical device comprising a shape memory alloy (SMA) portion having an austenitic and a martensitic state with a different configuration in each of these states, the SMA being transformable from a martensitic to an austenitic state by an austenitic transformation occurring in a temperature range between A.sub.s, a start temperature of the austenitic transformation, to A.sub.f, a finish temperature of the austenitic transformation, and being transformable from an austenitic state to a martensitic state by a martensitic transformation occurring in a temperature range lower than body temperature between M.sub.s, a start temperature of a martensitic transformation and M.sub.f, a finish temperature of the martensitic transformation, A.sub.s being lower than body temperature in an undeformed state; the device being characterized in that:the SMA portion is deformable from an undeformed first configuration assumed by it in the austenitic state to a deformed second configuration, such that the deformation converts it into a strain-induced martensitic or partial martensite with an increase in A.sub.s from its original temperature A.sub.s .degree., to a temperature A.sub.s '; and in thatwhen the SMA portion, once in said second configuration, is heated to a temperature higher than A.sub.s ', it transforms to an at least partial austenitic state, which transformation results in a change in configuration from the deformed second configuration towards the undeformed first configuration and in a decrease of A.sub.s from A.sub.s ' to A.sub.s .degree., such that the SMA portion is stable in the at least partial austenitic state at the body temperature.