An intravascular device and associated system which utilizes pressurized fluid to extract occlusive material. The device and system includes several unique features which provide desirable advantages over prior art devices. For example, the device is particularly suitable for removing occlusive material which is diffuse, friable, grumous-like, paste-like, granular, and/or chunky. The device includes independently movable fluid input and fluid output tubes and may be advanced over a guide wire. The fluid port holes are located immediately adjacent the distal end of the fluid output tube so as to engage the occlusive material without the need to first traverse the occlusive material with the device. The system utilizes a unique constant volume pump and associated pressure sensors to maintain balanced flow and immediately detect and correct conditions which may cause clinical complications.