Systems and apparatuses for use with a guidewire are provided. The systems/apparatuses can include a first housing, shaped to define a first channel through which the guidewire is slidable and a second housing, shaped to define a second channel through which the guidewire is slidable in at least a first direction toward the first housing. The systems/apparatuses can also include a guidewire-engaging element, disposed within the second housing, and configured to inhibit the guidewire from sliding through the second channel in a second direction away from the first housing. A tubular member having a lumen through which the guidewire is slidable and being slidably coupled to the first housing can also be included. Other embodiments are also described.
