Catheter systems of the invention are directed to the removal of occlusions, such as thrombi and plaque, within blood vessels. In certain aspects, catheter systems of the invention include an elongate body defining a first lumen and comprising a distal portion, an inner member configured for insertion into the first lumen, the inner member comprising an energy source configured to deliver therapeutic energy to a treatment site； and a dissolution element coupled to the distal portion of the elongate body. The dissolution element may include a heating element, steam, and a balloon.
