Implantable medical leads and methods of forming such leads are disclosed. An implantable medical lead includes a lead body, a swage base coupled to the lead body, and a polymeric member interposed at least in part between the swage base and at least one rigid component of the lead such as an electrode or annular ring. The swage base includes an annular-shaped body including a flange having a number of protrusions that extend radially outward from the flange. During a swaging process, the protrusions on the flange are compressed against the polymeric member, forming a number of channels in the member that mechanically bond the member to the swage base.