This patent document discloses perfusion catheters and related methods for treating complications related to CTO interventions or dilating a vessel occlusion while maintaining a passage through the treated vessel segment. A perfusion catheter can include an inflatable balloon coiled in a helical manner around a central axis into a series of windings. An inner surface of the series of windings, when inflated, can define a passage through the inflatable balloon. A catheter can also include an elongate shaft extending from a proximal portion to a distal portion, having an inner surface that defines a lumen for providing inflation fluid to, or withdrawing inflation fluid from, a distal end of the inflatable balloon. A catheter can further include a guidewire support tube including a lumen, separate from the lumen from the elongate shaft and the passage through the inflatable balloon, for receiving a guidewire.
