vibrations may indicate to the clinician holding fluid flow sensor 16 that fluid is or is not, respectively, flowing from catheter 12 to fluid pump 18. In examples in which a flow rate of fluid flow corresponds to a magnitude or frequency of vibrations, a change in magnitude or frequency of vibrations may indicate to the clinician holding fluid flow sensor 16 that a fluid flow rate is changing. 

[0085] Catheter 12 may be removed from the vasculature once the procedure is complete. 

[0086] As the thrombus is suctioned from the blood vessel through an inner lumen of catheter 12, fluid flow sensor 16 may provide the clinician operating aspiration system 10 with a haptic indication of fluid flow that indicates a condition related to engagement of the thrombus. FIG. 5 is an illustrative example graph of fluid flow versus time for an example aspiration procedure using aspiration system 10, such fluid flow being used to generate vibrations in fluid flow sensor 16. 

[0087] In the example of FIG. 5, the clinician may position the at least one opening 36 of catheter 12 near the thrombus, such that the thrombus partially blocks the at least one opening 36 (Ti). As a result of this partial blockage, the flow of fluid from catheter 12 to fluid pump 18, and thereby through fluid flow sensor 16, may be reduced. In examples in which a frequency or magnitude of vibrations generated by fluid flow sensor 16 corresponds to a flow rate of fluid through fluid flow sensor 6, this reduction in flow rate may cause a corresponding change in magnitude or frequency of vibrations, thereby providing an indication to the clinician that the thrombus has been at least partially engaged. 

[0088] In the example of FIG. 5, as the thrombus becomes further engaged, the thrombus may fully or substantially fully block the at least one opening 36 of catheter 12 (T2). For example, a flow of fluid may continue to decrease as a thrombus is drawn into catheter 12 and begins to more fully block the at least one opening 36 of catheter 12. In examples in which fluid flow sensor 16 is configured to produce vibrations above a particular fluid flow threshold (“Threshold”), at a certain reduction in fluid flow, fluid flow sensor 16 may produce vibrations that are below a haptic level of the clinician, or may produce no vibrations at all. This lack of haptic feedback may indicate to the clinician that flow of fluid has stopped or substantially stopped, thus indicated that the thrombus is fully engaged by catheter 12. In some examples, not shown in FIG. 5, the thrombus may be removed by removing catheter 12 while the thrombus is fully engaged with catheter 12. 

