An example multi-lumen member forming dual inflation portions of a catheter assembly for treating bifurcated vessels includes a main tube defining a main lumen and a main inflation portion. The member includes a side tube defining a side lumen and a side inflation portion, the side tube extending along at least a first length of the main tube. The member also includes a portion extending along the first length of the main tube and coupling the main tube to the side tube to form a dual lumen configuration.
