A stent-graft delivery system comprising: an elongate shaft (212, 612); a plurality of elongate cables (226, 626), wherein each cable (226, 626) extends over the elongate shaft (212, 612) and includes a first end, an intermediate portion (270, 670) configured to engage endmost crowns of a self-expanding stent of a stent-graft prosthesis (230, 630), and a second end (268, 668) that extends distally beyond the stent-graft prosthesis (230, 630); a guiding assembly (224, 624) disposed over the shaft (212, 612); a distal tip assembly (228, 628) coupled to a distal end of the shaft (212, 612), the distal tip assembly (228, 628) and the guiding assembly (224, 624) being moveable relative to each other, wherein a portion of the distal tip assembly (228, 628) extends proximally over an outer surface of a distal portion of the guiding assembly (224, 624) and constrains the second ends (268, 668) of the cables (226, 626) between the outer surface of the distal portion of the guiding assembly (224, 624) and an inner surface of the portion of the distal tip assembly (228, 628) in a first relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624) and wherein the distal tip assembly (228, 628) does not constrain the second ends (268, 668) of the cables (226, 626) in a second relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624), wherein, in the first relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624), tension on the cables (226, 626) may be selectively reduced for gradual continuous expansion of the endmost crowns of the stent or may be selectively increased for gradual continuous radial contraction of the endmost crowns of the stent. an elongate shaft (212, 612); a plurality of elongate cables (226, 626), wherein each cable (226, 626) extends over the elongate shaft (212, 612) and includes a first end, an intermediate portion (270, 670) configured to engage endmost crowns of a self-expanding stent of a stent-graft prosthesis (230, 630), and a second end (268, 668) that extends distally beyond the stent-graft prosthesis (230, 630); a guiding assembly (224, 624) disposed over the shaft (212, 612); a distal tip assembly (228, 628) coupled to a distal end of the shaft (212, 612), the distal tip assembly (228, 628) and the guiding assembly (224, 624) being moveable relative to each other, wherein a portion of the distal tip assembly (228, 628) extends proximally over an outer surface of a distal portion of the guiding assembly (224, 624) and constrains the second ends (268, 668) of the cables (226, 626) between the outer surface of the distal portion of the guiding assembly (224, 624) and an inner surface of the portion of the distal tip assembly (228, 628) in a first relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624) and wherein the distal tip assembly (228, 628) does not constrain the second ends (268, 668) of the cables (226, 626) in a second relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624), wherein, in the first relative position of the distal tip assembly (228, 628) and the guiding assembly (224, 624), tension on the cables (226, 626) may be selectively reduced for gradual continuous expansion of the endmost crowns of the stent or may be selectively increased for gradual continuous radial contraction of the endmost crowns of the stent.