MECHANISM FOR THE DEPLOYMENT OF ENDOVASCULAR IMPLANTS

摘要

A mechanism for the deployment of a filamentous endovascular device includes an elongate, flexible, hollow deployment tube having an open proximal end, and a coupling element attached to the proximal end of the endovascular device. The deployment tube includes a distal section terminating in an open distal end, with a lumen defined between the proximal and distal ends. A retention sleeve is fixed around the distal section and includes a distal extension extending a short distance past the distal end of the deployment tube. The endovascular device is attached to the distal end of the deployment tube during the manufacturing process by fixing the retention sleeve around the coupling element, so that the coupling element is releasably held within the distal extension of the deployment tube. In use, the deployment tube, with the implant attached to its distal end, is passed through a microcatheter to a target vascular site until the endovascular device is deployed within the site. To detach the endovascular device from the deployment tube, a biocompatible liquid is injected through the lumen of the deployment tube so as to apply pressure to the upstream side of the coupling element, which is thus pushed out of the retention sleeve by the fluid pressure, thereby detaching the endovascular device from the deployment tube. The coupling element may be a solid "plug" of polymeric material or metal, or it may be formed of a hydrophilic polymer that softens and becomes somewhat lubricious when contacted by the injected liquid. With the latter type of material, the hydration of the hydrophilic material results in physical changes that reduce the adhesion between the coupling element and the sleeve. Alternatively, the coupling element can be made principally of a non-hydrophilic material, with a hydrophilic coating.