A catheter is disclosed that allows selective direction of a surgical tool into multiple blood vessels of a patient. The catheter includes a catheter body that has a main exit port and a side exit port. An internal balloon is provided within the catheter body. The internal balloon is inflatable, and can be located at or near a distal portion of the side exit port. When deflated, the internal balloon allows the surgical tool to advance past the side exit port and out the main exit port. When inflated, the internal balloon directs the surgical tool to advance out the side exit port instead of the main exit port.