The present invention advantageously provides improved systems and methods for intraluminal delivery of implantable occlusive elements, particularly hydratable polymeric filaments. In particular, the systems and methods of the present invention minimize or avoid clumping or clogging a delivery catheter. This is accomplished by utilization of a reinforcing member or sheath that provides an advancing axial force along or over a length of the occlusive element. When the reinforcing member or sheath is pulled in a proximal direction, the occlusive element is advanced to a target site, which may comprise an aneurysm, vasculature of a tumor, arterio-venous malformations, fistulas, or burst blood vessels.