A tissue-removing catheter comprising: an elongate catheter body having opposite distal and proximal portions and being sized and shaped for introduction into a body lumen of a subject, the catheter body having a window at the distal portion thereof; a drive shaft extending longitudinally within the catheter body, wherein the drive shaft is rotatable relative to the catheter body about a longitudinal axis of the drive shaft; a cutting element at the distal portion of the elongate catheter body adjacent the window, the cutting element having opposite proximal and distal ends and a longitudinal axis extending therebetween, the cutting element being operatively connected to the drive shaft for rotation about the longitudinal axis of the cutting element, the cutting element including an annular cutting edge at the distal end of the cutting element surrounding the longitudinal axis of the cutting element, the annular cutting edge having a radius as taken from the longitudinal axis of the cutting element, an inner surface extending proximally from the cutting edge and defining an internal cavity, at least one raised element in the internal cavity having a leading radial wall extending generally radially inward toward the longitudinal axis of the cutting element, the leading radial wall having a radially outermost portion relative to the longitudinal axis of the cutting element, wherein the cutting element is extendable through the window during operation such that as the cutting element is being rotated about its longitudinal axis, less than an entire radial portion of the leading radial wall passes through the window, wherein the radially outermost portion is spaced apart radially from the inner surface of the cutting element, and wherein the cutting element includes an undercut extending generally radially into the raised element such that the radially outermost portion is spaced apart radially from the inner surface of the cutting element. an elongate catheter body having opposite distal and proximal portions and being sized and shaped for introduction into a body lumen of a subject, the catheter body having a window at the distal portion thereof; a drive shaft extending longitudinally within the catheter body, wherein the drive shaft is rotatable relative to the catheter body about a longitudinal axis of the drive shaft; a cutting element at the distal portion of the elongate catheter body adjacent the window, the cutting element having opposite proximal and distal ends and a longitudinal axis extending therebetween, the cutting element being operatively connected to the drive shaft for rotation about the longitudinal axis of the cutting element, the cutting element including an annular cutting edge at the distal end of the cutting element surrounding the longitudinal axis of the cutting element, the annular cutting edge having a radius as taken from the longitudinal axis of the cutting element, an inner surface extending proximally from the cutting edge and defining an internal cavity, at least one raised element in the internal cavity having a leading radial wall extending generally radially inward toward the longitudinal axis of the cutting element, the leading radial wall having a radially outermost portion relative to the longitudinal axis of the cutting element, an annular cutting edge at the distal end of the cutting element surrounding the longitudinal axis of the cutting element, the annular cutting edge having a radius as taken from the longitudinal axis of the cutting element, an inner surface extending proximally from the cutting edge and defining an internal cavity, at least one raised element in the internal cavity having a leading radial wall extending generally radially inward toward the longitudinal axis of the cutting element, the leading radial wall having a radially outermost portion relative to the longitudinal axis of the cutting element, wherein the cutting element is extendable through the window during operation such that as the cutting element is being rotated about its longitudinal axis, less than an entire radial portion of the leading radial wall passes through the window, wherein the radially outermost portion is spaced apart radially from the inner surface of the cutting element, and wherein the cutting element includes an undercut extending generally radially into the raised element such that the radially outermost portion is spaced apart radially from the inner surface of the cutting element.