A system is provided for crossing an occlusion within a blood vessel or cylindrical body cavity. The system includes a guide catheter and a catheter device. The guide catheter comprises a proximal portion to be disposed outside a patient and a distal portion to be disposed inside the patient adjacent to an occlusion. The system has an expandable member disposed adjacent to a distal end thereof. The expandable member can be coupled with the guide catheter or the catheter device, or an expandable member can be coupled with each of the guide catheter and the catheter device. The catheter device, which can be configured for treating an occlusion, includes a proximal portion, a distal portion, or an elongate body extending between the proximal and distal portions.
