A system for removal of blood or thrombus includes an aspiration catheter having an elongate shaft including an aspiration lumen having proximal end configured to couple to a vacuum source, and a distal end having an orifice, an elongate member configured for placement through the aspiration lumen and having a distal portion including a disruption element configured to disrupt thrombus within the aspiration lumen, and a monitoring device configured for removable connection in between the aspiration catheter and the vacuum source, and including a housing, a pressure sensor in fluid communication with an interior of the housing, a measurement device coupled to the pressure sensor and configured for measuring deviations in fluid pressure, and a communication device coupled to the measurement device and configured to generate an alert signal when a deviation in fluid pressure measured by the measurement device exceeds a pre-set threshold.