A method for placing a stent into a main vessel such that the stent side hole aligns with a branch vessel ostium comprises inserting a main vessel guidewire into the main vessel and a branch vessel guidewire into the main vessel until a distal end of the branch vessel guidewire passes into the branch vessel. A catheter system is positioned over the main vessel guidewire and the branch vessel guidewire. The catheter system is advanced over the guidewires until the catheter body passes beyond the ostium of the branch vessel and the side member extends into the branch vessel. Marker separation is observed to indicate the catheter body passed beyond the ostium and the side member extends into the branch vessel. The balloon is inflated to deploy the stent with the side hole being aligned with the ostium. The balloon is deflated, and the catheter system is withdrawn.