High Intermediate Risk Pulmonary Embolism: The Use of Very Low Dose Catheter-Directed Ultrasound- Accelerated Thrombolysis

Objective: To determine the hemodynamic benefit, clot burden reduction and safety utilizing an ultra-low dose of Tissue Plasminogen Activator (TPA) with Catheter directed Ultrasound accelerated thrombolysis (USAT) in the management of high Intermediate Risk Pulmonary Embolism.
Design: Retrospective, observational case series.
Setting: Single Center Academic Community Hospital.
Patients: Fifty-two consecutive patients (27 males) with high Intermediate Risk PE treated with USAT were analyzed.
Measurements and Main Results: Forty-nine patients underwent bilateral USAT with 0.5 mg/hr/catheter of TPA (unilateral: 1.0 mg/hr). Mean duration of therapy was 22.08 + 4.90 hours. Changes in pulmonary artery pressure (PAP), Clot obstruction index by Miller score and procedure related bleeding complications were assessed. Paired t-testing was used to determine significance Mean RV/LV ratio was 1.52 + 0.36. Miller score decreased 55.0% (mean 19.7 + 3.8 to 8.9 + 4.7; p value < 0.0001). The systolic PAP decreased 7.3% from 63.6 + 15.1 mmHg to 59.0 + 17.5 mmHg (p value = 0.0045). The mean PAP decreased 5.4% from 37.5 + 8.0 mmHg to 35.5 + 9.1 mmHg (p value = 0.0097). No procedural or bleeding related complications occurred.
Conclusion: Low dose USAT with 0.5mg/hr/catheter with TPA for 24 hours is highly effective in reducing clot burden and PAP without bleeding or procedural related complications in high Intermediate Risk PE.