Abstract: Systems for less invasive medical procedures comprise a filter device mounted on an integrated guiding structure and an aspiration catheter. These components can be used together or separately, and the system can be used with other medical devices that are designed for less invasive procedures, such as procedures in a patient's vasculature. The catheter can have a radiopaque band that is held in place under metal wire embedded within the polymer forming the tube of the catheter. In some embodiments, the aspiration catheter has a small diameter distal portion that can access into small diameter vessels in which the distal portion has a smaller average diameter than the remaining tube of the catheter.