Mechanical versus chemical thrombolysis: an in vitro differentiation of thrombolytic mechanisms

J Vasc Interv Radiol. 2000 Feb;11(2 Pt 1):199-205. doi: 10.1016/s1051-0443(07)61465-1.


Purpose: To assess differing mechanisms of thrombolysis determining time to reperfusion, completeness of thrombus dissolution, and embolic potential.

Materials and methods: An in vitro perfusion model designed to mimic arterial flow conditions was created. Bifurcated limbs allowed continuous flow through one channel and the placement of radiolabeled (iodine-125) thrombus housed in a 5-cm segment of polytetrafluoroethylene graft in the other. The three experimental groups consisted of a standard continuous urokinase infusion, a pulsed pressurized injection of saline, and a similar injection with urokinase. A continuous infusion of 5% dextrose served as a control group. Time to reflow (as assessed with ultrasonic flow monitoring), completeness of thrombus dissolution (I-125 liberated into solution), and the number and size of embolic particles produced (detected by a series of graduated filter sizes) were analyzed.

Results: Time to reflow was significantly faster for both groups when pressurized injections were used (P < .001). There was no reflow in the control arm at 90 minutes. Completeness of thrombus dissolution was higher when a continuous infusion of urokinase was used in comparison to either of the power injection groups or the control (P < .05). The amount of embolic debris produced was significantly lower with a continuous infusion of urokinase compared with either of the power lysis groups (P < .05), but significantly greater than the control arm (P < .001). The size of the embolic particles in the power pulsed lysis groups was significantly decreased by the addition of urokinase (P < .05).

Conclusions: Reflow is more rapidly established by the use of mechanical means. However, a less complete dissolution of thrombus in conjunction with a greater amount of embolic debris is achieved with this approach. The size of the embolic particles produced is reduced by the addition of a thrombolytic agent.

Publication types

  • Comparative Study

MeSH terms

  • Blood Vessel Prosthesis
  • Graft Occlusion, Vascular / therapy
  • Humans
  • Models, Cardiovascular
  • Plasminogen Activators / administration & dosage
  • Plasminogen Activators / therapeutic use*
  • Polytetrafluoroethylene
  • Thrombectomy
  • Thrombolytic Therapy / methods*
  • Thrombosis / therapy*
  • Urokinase-Type Plasminogen Activator / administration & dosage
  • Urokinase-Type Plasminogen Activator / therapeutic use*


  • Polytetrafluoroethylene
  • Plasminogen Activators
  • Urokinase-Type Plasminogen Activator