Methods of advancing a laser catheter across an occlusion are described. They may include the steps of advancing a guidewire through a first proximal lumen and a distal lumen of the catheter into a first region of the occlusion, retracting the guidewire from the distal lumen, and advancing a diagnostic device from a second proximal lumen of the catheter to examine the occlusion. The methods may also include retracting the diagnostic device from the distal lumen and advancing the guidewire through the distal lumen. The laser catheter may be activated to create a lumen through the occlusion.
