Methods, devices and systems are described for treating venous insufficiency in which the vein is compressed at least partially along a treatment zone. A system can be provided including an injection device, such as a glue gun, that is operably connected to a delivery catheter that can be advanced across a treatment zone in the vein. The delivery catheter can be used to deliver one, two, or more boluses of media (e.g., cyanoacrylate) to occlude the vein along different spaced-apart sections of the treatment zone. External compression can also be applied to the vein by a compression element, such as a hand or multifunctional ultrasound transducer, to occlude portions of the vein along the treatment zone prior to or during the introduction of the boluses of media.