A helical stent having a central helically wound portion, and cylindrical ends
is provided. A transition zone having struts of different lengths is provided between
the helical portion and each cylindrical portion. A junction defining a strut trident
is provided between the transition zone and the helical portion. This construction
provides a highly flexible stent, permits connecting bridges that are in the same
basic orientation, and enables the hoops of the helical, cylindrical, and transitions
zones to remain "in phase" such that the stent can easily expand and collapse.
According to another aspect of the invention, the kerf between adjacent struts
does not go all the way to the end of those struts. The longer struts can have
substantially the same flexibility and expansion force as the shorter struts of
the transition by making all the kerfs approximately the same length.