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.