vasculature of a patient. Aspiration pump 6 is also configured to create a negative pressure (i.e., vacuum or suction) on inner catheter 14, e.g., to draw fluid through an inner lumen of inner catheter 14 into a reservoir of aspiration pump 6. For example, aspiration pump 6 may include one or more ports configured to couple to aspiration tubing 8, such that the positive or negative pressure created by aspiration pump 6 may be applied to the respective port and through aspiration tubing 8 and other portions of a fluid pathway between aspiration tubing 8 and a respective inner lumen of outer catheter 12 and/or inner lumen of inner catheter 14. A variety of pumps may be used for aspiration pump 6 including, but not limited to, positive displacement pumps, centrifugal pumps, and the like. While illustrated as a single pump, aspiration pump 6 may include a plurality of pump units, such as a first pump for creating the positive pressure and a second pump for creating the negative pressure. [0058] FIG. IB is a schematic diagram illustrating example aspiration catheter system 10 of FIG. 1A. Outer catheter 12 defines an outer catheter lumen 16 and an outer catheter distal opening 18. Outer catheter 12 may include various structural components, such as an inner liner, an outer jacket, and a structural support member, such as a coil and/or or a braid, positioned between at least a portion of the inner liner and at least a portion of the outer jacket. [0059] Outer catheter lumen 16 is configured to transport fluid, such as aspiration fluid, blood, and particulates in the fluid, from a proximal end of outer catheter 12, such as from aspiration pump 6 of FIG. 1A, to a distal end of outer catheter 12, such as outer catheter distal opening 18. Outer catheter lumen 16 may be sized to receive at least a portion of inner catheter 14 while allowing aspiration fluid under a positive pressure provided by an aspiration pump to be delivered to outer catheter opening 18. In some examples, outer catheter 12 may have an inner diameter Di between or equal to about 0.075 inches (about 1.9 millimeters (mm)) and/or about 0.087 inches (about 2.2 mm), which corresponds to the circumference of outer catheter lumen 16. In some examples, the inner diameter and/or inner circumference of outer catheter lumen 16 may be relatively constant (e.g., constant or nearly constant) from a proximal end of outer catheter 12 to outer catheter opening 18. [0060] Outer catheter distal opening 18 is an opening of outer catheter lumen 16 at a distal end of outer catheter 12. Outer catheter distal opening 18 is configured to receive inner catheter 14, such that at least a portion of inner catheter 14 may be positioned within outer catheter lumen 16. Outer catheter 12 also includes an outer catheter