Schematic representation of the rabbit thrombolysis model. A thrombus, formed from rabbit whole blood, is depicted superimposed on a stenosis in a denuded and damaged segment of the aorta. The external constrictor, by itself, restricts blood flow by at least 66%, reducing the flow from 15 mL/min to 3 to 5 mL/min, thereby producing a critical stenosis. Blood flow is not observed after production of the thrombus. The spatial relationship of both the blood pressure and flow probes with respect to the thrombus is indicated. To the right of the schematic representation of the rabbit are tracings from both blood pressure and flow probes, which indicate a representative recording of cyclic flow observed during treatment with tPA and PTI.