Randomized, controlled trial of ultrasound-assisted catheter-directed thrombolysis for acute intermediate-risk pulmonary embolism

Circulation. 2014 Jan 28;129(4):479-86. doi: 10.1161/CIRCULATIONAHA.113.005544. Epub 2013 Nov 13.


Background: In patients with acute pulmonary embolism, systemic thrombolysis improves right ventricular (RV) dilatation, is associated with major bleeding, and is withheld in many patients at risk. This multicenter randomized, controlled trial investigated whether ultrasound-assisted catheter-directed thrombolysis (USAT) is superior to anticoagulation alone in the reversal of RV dilatation in intermediate-risk patients.

Methods and results: Fifty-nine patients (63±14 years) with acute main or lower lobe pulmonary embolism and echocardiographic RV to left ventricular dimension (RV/LV) ratio ≥1.0 were randomized to receive unfractionated heparin and an USAT regimen of 10 to 20 mg recombinant tissue plasminogen activator over 15 hours (n=30; USAT group) or unfractionated heparin alone (n=29; heparin group). Primary outcome was the difference in the RV/LV ratio from baseline to 24 hours. Safety outcomes included death, major and minor bleeding, and recurrent venous thromboembolism at 90 days. In the USAT group, the mean RV/LV ratio was reduced from 1.28±0.19 at baseline to 0.99±0.17 at 24 hours (P<0.001); in the heparin group, mean RV/LV ratios were 1.20±0.14 and 1.17±0.20, respectively (P=0.31). The mean decrease in RV/LV ratio from baseline to 24 hours was 0.30±0.20 versus 0.03±0.16 (P<0.001), respectively. At 90 days, there was 1 death (in the heparin group), no major bleeding, 4 minor bleeding episodes (3 in the USAT group and 1 in the heparin group; P=0.61), and no recurrent venous thromboembolism.

Conclusions: In patients with pulmonary embolism at intermediate risk, a standardized USAT regimen was superior to anticoagulation with heparin alone in reversing RV dilatation at 24 hours, without an increase in bleeding complications.

Clinical trial registration url: http://www.clinicaltrials.gov. Unique identifier: NCT01166997.

Keywords: pulmonary embolism.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Aged
  • Dose-Response Relationship, Drug
  • Drug Therapy, Combination
  • Female
  • Hemorrhage / epidemiology
  • Heparin / administration & dosage
  • Heparin / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care
  • Pulmonary Embolism / diagnostic imaging*
  • Pulmonary Embolism / drug therapy*
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / therapeutic use
  • Risk Factors
  • Thrombolytic Therapy / methods*
  • Tissue Plasminogen Activator / administration & dosage
  • Tissue Plasminogen Activator / therapeutic use*
  • Treatment Outcome
  • Ultrasonography, Interventional*
  • Vascular Access Devices*


  • Recombinant Proteins
  • Heparin
  • Tissue Plasminogen Activator

Associated data

  • ClinicalTrials.gov/NCT01166997