title: Catheter-delivered ultrasound potentiates in vitro thrombolysis.
abstract: OBJECTIVE
  To develop a catheter-directed method to enhance urokinase- mediated thrombolysis with use of ultrasound.
  
  
  METHODS
  A prototype catheter was constructed by using a 9-F piezoelectric crystal capable of producing 640-kHz pulsed ultrasound energy. Clots formed in vitro from whole blood were trace-labeled with iodine-125 fibrinogen, and the release of radiolabeled fibrin degradation products was measured in the presence of urokinase, ultrasound, or a combination of urokinase and ultrasound.
  
  
  RESULTS
  By 30 minutes, clot lysis was more complete with urokinase plus ultrasound (78.7% +/- 5.3 [mean +/- SD]) than with ultrasound alone (19.3% +/- 10.0) or urokinase alone (47.9% +/- 10.0) (P < .001 for ultrasound and urokinase vs either alone). The time to 50% clot lysis was shortened by 46% on average with the application of urokinase and ultrasound compared with urokinase alone (P < .03).
  
  
  CONCLUSIONS
  Catheter-based ultrasound enhances enzymatic thrombolysis in vitro and may be a practical means to reduce the dose of enzyme and the time needed to achieve clot lysis in vivo.
authors: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors: R D
authors: RD
authors: Shlansky-Goldberg
authors: D B
authors: DB
authors: Cines
authors: C M
authors: CM
authors: Sehgal
mesh_terms: D000328:Adult; D000800:Angioplasty, Balloon / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D013923:Thromboembolism / Q000628:therapy*; D015912:Thrombolytic Therapy / Q000295:instrumentation*; D013997:Time Factors; D014464:Ultrasonic Therapy / Q000295:instrumentation*; D014568:Urokinase-Type Plasminogen Activator / Q000008:administration & dosage*
chemical_list: D014568:Urokinase-Type Plasminogen Activator