An elongate medical device includes an elongate core and a substantially flat sheet formed into a tubular body defining a longitudinal axis and disposed around at least a portion of the elongate core, where the flat sheet has a length, and where a cross-sectional thickness of the sheet varies along the length of the sheet. The tubular body has proximal and distal portions, and a cross-sectional thickness of the sheet forming the distal portion of the tubular body may be less than a cross-sectional thickness of the sheet forming the proximal portion of the tubular body. A cross-sectional thickness of the sheet forming the tubular body preferably tapers from the proximal portion to the distal portion.
