An expandable stent and delivery system are provided for treating body vessel defects, such as partially occluded blood vessels and aneurysms. The delivery system includes a core member having a threaded core member portion configured to interlock with a threaded strut member portion of the expandable stent. The expandable stent is mounted thusly onto the core member for movement within a delivery catheter and deployment to a body vessel defect. The deployment catheter is used to compress the interlocked threaded strut member portion into engagement with the threaded core member portion.